1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
9 * All rights reserved.
10 *
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34
35 /*
36 * Dynamic linker for ELF.
37 *
38 * John Polstra <jdp@polstra.com>.
39 */
40
41 #include <sys/param.h>
42 #include <sys/ktrace.h>
43 #include <sys/mman.h>
44 #include <sys/mount.h>
45 #include <sys/stat.h>
46 #include <sys/sysctl.h>
47 #include <sys/uio.h>
48 #include <sys/utsname.h>
49
50 #include <dlfcn.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <stdarg.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59
60 #include "debug.h"
61 #include "libmap.h"
62 #include "notes.h"
63 #include "rtld.h"
64 #include "rtld_libc.h"
65 #include "rtld_malloc.h"
66 #include "rtld_paths.h"
67 #include "rtld_printf.h"
68 #include "rtld_tls.h"
69 #include "rtld_utrace.h"
70
71 /* Types. */
72 typedef void (*func_ptr_type)(void);
73 typedef void *(*path_enum_proc)(const char *path, size_t len, void *arg);
74
75 /* Variables that cannot be static: */
76 extern struct r_debug r_debug; /* For GDB */
77 extern int _thread_autoinit_dummy_decl;
78 extern void (*__cleanup)(void);
79
80 struct dlerror_save {
81 int seen;
82 char *msg;
83 };
84
85 struct tcb_list_entry {
86 TAILQ_ENTRY(tcb_list_entry) next;
87 };
88
89 /*
90 * Function declarations.
91 */
92 static bool allocate_tls_offset_common(size_t *offp, size_t tlssize,
93 size_t tlsalign, size_t tlspoffset);
94 static const char *basename(const char *);
95 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
96 const Elf_Dyn **, const Elf_Dyn **);
97 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
98 const Elf_Dyn *);
99 static bool digest_dynamic(Obj_Entry *, int);
100 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
101 static void distribute_static_tls(Objlist *);
102 static Obj_Entry *dlcheck(void *);
103 static int dlclose_locked(void *, RtldLockState *);
104 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
105 int lo_flags, int mode, RtldLockState *lockstate);
106 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
107 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
108 static bool donelist_check(DoneList *, const Obj_Entry *);
109 static void dump_auxv(Elf_Auxinfo **aux_info);
110 static void errmsg_restore(struct dlerror_save *);
111 static struct dlerror_save *errmsg_save(void);
112 static void *fill_search_info(const char *, size_t, void *);
113 static char *find_library(const char *, const Obj_Entry *, int *);
114 static const char *gethints(bool);
115 static void hold_object(Obj_Entry *);
116 static void unhold_object(Obj_Entry *);
117 static void init_dag(Obj_Entry *);
118 static void init_marker(Obj_Entry *);
119 static void init_pagesizes(Elf_Auxinfo **aux_info);
120 static void init_rtld(caddr_t, Elf_Auxinfo **);
121 static void initlist_add_neededs(Needed_Entry *, Objlist *, Objlist *);
122 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *,
123 Objlist *);
124 static void initlist_for_loaded_obj(Obj_Entry *obj, Obj_Entry *tail,
125 Objlist *list);
126 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
127 static void linkmap_add(Obj_Entry *);
128 static void linkmap_delete(Obj_Entry *);
129 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
130 static void unload_filtees(Obj_Entry *, RtldLockState *);
131 static int load_needed_objects(Obj_Entry *, int);
132 static int load_preload_objects(const char *, bool);
133 static int load_kpreload(const void *addr);
134 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
135 static void map_stacks_exec(RtldLockState *);
136 static int obj_disable_relro(Obj_Entry *);
137 static int obj_enforce_relro(Obj_Entry *);
138 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
139 static void objlist_call_init(Objlist *, RtldLockState *);
140 static void objlist_clear(Objlist *);
141 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
142 static void objlist_init(Objlist *);
143 static void objlist_push_head(Objlist *, Obj_Entry *);
144 static void objlist_push_tail(Objlist *, Obj_Entry *);
145 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
146 static void objlist_remove(Objlist *, Obj_Entry *);
147 static int open_binary_fd(const char *argv0, bool search_in_path,
148 const char **binpath_res);
149 static int parse_args(char *argv[], int argc, bool *use_pathp, int *fdp,
150 const char **argv0, bool *dir_ignore);
151 static int parse_integer(const char *);
152 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
153 static void print_usage(const char *argv0);
154 static void release_object(Obj_Entry *);
155 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
156 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
157 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
158 int flags, RtldLockState *lockstate);
159 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
160 RtldLockState *);
161 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
162 static int rtld_dirname(const char *, char *);
163 static int rtld_dirname_abs(const char *, char *);
164 static void *rtld_dlopen(const char *name, int fd, int mode);
165 static void rtld_exit(void);
166 static void rtld_nop_exit(void);
167 static char *search_library_path(const char *, const char *, const char *,
168 int *);
169 static char *search_library_pathfds(const char *, const char *, int *);
170 static const void **get_program_var_addr(const char *, RtldLockState *);
171 static void set_program_var(const char *, const void *);
172 static int symlook_default(SymLook *, const Obj_Entry *refobj);
173 static int symlook_global(SymLook *, DoneList *);
174 static void symlook_init_from_req(SymLook *, const SymLook *);
175 static int symlook_list(SymLook *, const Objlist *, DoneList *);
176 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
177 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
178 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
179 static void *tls_get_addr_slow(struct tcb *, int, size_t, bool) __noinline;
180 static void trace_loaded_objects(Obj_Entry *, bool);
181 static void unlink_object(Obj_Entry *);
182 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
183 static void unref_dag(Obj_Entry *);
184 static void ref_dag(Obj_Entry *);
185 static char *origin_subst_one(Obj_Entry *, char *, const char *, const char *,
186 bool);
187 static char *origin_subst(Obj_Entry *, const char *);
188 static bool obj_resolve_origin(Obj_Entry *obj);
189 static void preinit_main(void);
190 static void rtld_recalc_bind_not(const char *);
191 static void rtld_recalc_dangerous_ld_env(void);
192 static void rtld_recalc_debug(const char *);
193 static void rtld_recalc_path_rpath(const char *);
194 static int rtld_verify_versions(const Objlist *);
195 static int rtld_verify_object_versions(Obj_Entry *);
196 static void object_add_name(Obj_Entry *, const char *);
197 static int object_match_name(const Obj_Entry *, const char *);
198 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
199 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
200 struct dl_phdr_info *phdr_info);
201 static uint32_t gnu_hash(const char *);
202 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
203 const unsigned long);
204
205 struct ld_env_var_desc;
206 static void rtld_set_var_bind_not(struct ld_env_var_desc *lvd);
207 static void rtld_set_var_bind_now(struct ld_env_var_desc *lvd);
208 static void rtld_set_var_debug(struct ld_env_var_desc *lvd);
209 static void rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd);
210 static void rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd);
211 static void rtld_set_var_library_path(struct ld_env_var_desc *lvd);
212 static void rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd);
213 static void rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd);
214 static void rtld_set_var_loadfltr(struct ld_env_var_desc *lvd);
215
216 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
217 void _r_debug_postinit(struct link_map *) __noinline __exported;
218
219 int __sys_openat(int, const char *, int, ...);
220
221 /*
222 * Data declarations.
223 */
224 struct r_debug r_debug __exported; /* for GDB; */
225 static bool libmap_disable; /* Disable libmap */
226 static bool ld_loadfltr; /* Immediate filters processing */
227 static const char *libmap_override; /* Maps to use in addition to libmap.conf */
228 static bool trust; /* False for setuid and setgid programs */
229 static bool dangerous_ld_env; /* True if environment variables have been
230 used to affect the libraries loaded */
231 bool ld_bind_not; /* Disable PLT update */
232 static const char *ld_bind_now; /* Environment variable for immediate binding */
233 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides
234 weak definition */
235 static const char *ld_library_path; /* Environment variable for search path */
236 static const char
237 *ld_library_dirs; /* Environment variable for library descriptors */
238 static const char *ld_preload; /* Environment variable for libraries to
239 load first */
240 static const char *ld_preload_fds; /* Environment variable for libraries
241 represented by descriptors */
242 static const char
243 *ld_elf_hints_path; /* Environment variable for alternative hints path */
244 static const char *ld_tracing; /* Called from ldd to print libs */
245 static const char *ld_utrace; /* Use utrace() to log events. */
246 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
247 static Obj_Entry *obj_main; /* The main program shared object */
248 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
249 static unsigned int obj_count; /* Number of objects in obj_list */
250 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
251 size_t ld_static_tls_extra = /* Static TLS extra space (bytes) */
252 RTLD_STATIC_TLS_EXTRA;
253
254 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
255 STAILQ_HEAD_INITIALIZER(list_global);
256 static Objlist list_main = /* Objects loaded at program startup */
257 STAILQ_HEAD_INITIALIZER(list_main);
258 static Objlist list_fini = /* Objects needing fini() calls */
259 STAILQ_HEAD_INITIALIZER(list_fini);
260
261 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
262
263 #define GDB_STATE(s, m) \
264 r_debug.r_state = s; \
265 r_debug_state(&r_debug, m);
266
267 extern Elf_Dyn _DYNAMIC;
268 #pragma weak _DYNAMIC
269
270 int dlclose(void *) __exported;
271 char *dlerror(void) __exported;
272 void *dlopen(const char *, int) __exported;
273 void *fdlopen(int, int) __exported;
274 void *dlsym(void *, const char *) __exported;
275 dlfunc_t dlfunc(void *, const char *) __exported;
276 void *dlvsym(void *, const char *, const char *) __exported;
277 int dladdr(const void *, Dl_info *) __exported;
278 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
279 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
280 int dlinfo(void *, int, void *) __exported;
281 int _dl_iterate_phdr_locked(__dl_iterate_hdr_callback, void *) __exported;
282 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
283 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
284 int _rtld_get_stack_prot(void) __exported;
285 int _rtld_is_dlopened(void *) __exported;
286 void _rtld_error(const char *, ...) __exported;
287 const char *rtld_get_var(const char *name) __exported;
288 int rtld_set_var(const char *name, const char *val) __exported;
289
290 /* Only here to fix -Wmissing-prototypes warnings */
291 int __getosreldate(void);
292 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
293 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
294
295 int npagesizes;
296 static int osreldate;
297 size_t *pagesizes;
298 size_t page_size;
299
300 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC;
301 static int max_stack_flags;
302
303 /*
304 * Global declarations normally provided by crt1. The dynamic linker is
305 * not built with crt1, so we have to provide them ourselves.
306 */
307 char *__progname;
308 char **environ;
309
310 /*
311 * Used to pass argc, argv to init functions.
312 */
313 int main_argc;
314 char **main_argv;
315
316 /*
317 * Globals to control TLS allocation.
318 */
319 size_t tls_last_offset; /* Static TLS offset of last module */
320 size_t tls_last_size; /* Static TLS size of last module */
321 size_t tls_static_space; /* Static TLS space allocated */
322 static size_t tls_static_max_align;
323 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
324 int tls_max_index = 1; /* Largest module index allocated */
325
326 static TAILQ_HEAD(, tcb_list_entry) tcb_list =
327 TAILQ_HEAD_INITIALIZER(tcb_list);
328 static size_t tcb_list_entry_offset;
329
330 static bool ld_library_path_rpath = false;
331 bool ld_fast_sigblock = false;
332
333 /*
334 * Globals for path names, and such
335 */
336 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
337 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
338 const char *ld_path_rtld = _PATH_RTLD;
339 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
340 const char *ld_env_prefix = LD_;
341
342 static void (*rtld_exit_ptr)(void);
343
344 /*
345 * Fill in a DoneList with an allocation large enough to hold all of
346 * the currently-loaded objects. Keep this as a macro since it calls
347 * alloca and we want that to occur within the scope of the caller.
348 */
349 #define donelist_init(dlp) \
350 ((dlp)->objs = alloca(obj_count * sizeof(dlp)->objs[0]), \
351 assert((dlp)->objs != NULL), (dlp)->num_alloc = obj_count, \
352 (dlp)->num_used = 0)
353
354 #define LD_UTRACE(e, h, mb, ms, r, n) \
355 do { \
356 if (ld_utrace != NULL) \
357 ld_utrace_log(e, h, mb, ms, r, n); \
358 } while (0)
359
360 static void
ld_utrace_log(int event,void * handle,void * mapbase,size_t mapsize,int refcnt,const char * name)361 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
362 int refcnt, const char *name)
363 {
364 struct utrace_rtld ut;
365 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] __nonstring =
366 RTLD_UTRACE_SIG;
367
368 memset(&ut, 0, sizeof(ut)); /* clear holes */
369 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
370 ut.event = event;
371 ut.handle = handle;
372 ut.mapbase = mapbase;
373 ut.mapsize = mapsize;
374 ut.refcnt = refcnt;
375 if (name != NULL)
376 strlcpy(ut.name, name, sizeof(ut.name));
377 utrace(&ut, sizeof(ut));
378 }
379
380 struct ld_env_var_desc {
381 const char *const n;
382 const char *val;
383 const bool unsecure : 1;
384 const bool can_update : 1;
385 bool owned : 1;
386 void (*const on_update)(struct ld_env_var_desc *);
387 };
388 #define LD_ENV_DESC(var, unsec, ...) \
389 [LD_##var] = { .n = #var, .unsecure = unsec, __VA_ARGS__ }
390
391 static struct ld_env_var_desc ld_env_vars[] = {
392 LD_ENV_DESC(BIND_NOW, false, .can_update = true,
393 .on_update = rtld_set_var_bind_now),
394 LD_ENV_DESC(PRELOAD, true),
395 LD_ENV_DESC(LIBMAP, true),
396 LD_ENV_DESC(LIBRARY_PATH, true, .can_update = true,
397 .on_update = rtld_set_var_library_path),
398 LD_ENV_DESC(LIBRARY_PATH_FDS, true, .can_update = true,
399 .on_update = rtld_set_var_library_path_fds),
400 LD_ENV_DESC(LIBMAP_DISABLE, true, .can_update = true,
401 .on_update = rtld_set_var_libmap_disable),
402 LD_ENV_DESC(BIND_NOT, true, .can_update = true,
403 .on_update = rtld_set_var_bind_not),
404 LD_ENV_DESC(DEBUG, true, .can_update = true,
405 .on_update = rtld_set_var_debug),
406 LD_ENV_DESC(ELF_HINTS_PATH, true),
407 LD_ENV_DESC(LOADFLTR, true, .can_update = true,
408 .on_update = rtld_set_var_loadfltr),
409 LD_ENV_DESC(LIBRARY_PATH_RPATH, true, .can_update = true,
410 .on_update = rtld_set_var_library_path_rpath),
411 LD_ENV_DESC(PRELOAD_FDS, true),
412 LD_ENV_DESC(DYNAMIC_WEAK, true, .can_update = true,
413 .on_update = rtld_set_var_dynamic_weak),
414 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false),
415 LD_ENV_DESC(UTRACE, false, .can_update = true),
416 LD_ENV_DESC(DUMP_REL_PRE, false, .can_update = true),
417 LD_ENV_DESC(DUMP_REL_POST, false, .can_update = true),
418 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false),
419 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false),
420 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false),
421 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false),
422 LD_ENV_DESC(SHOW_AUXV, true),
423 LD_ENV_DESC(STATIC_TLS_EXTRA, false),
424 LD_ENV_DESC(NO_DL_ITERATE_PHDR_AFTER_FORK, false),
425 };
426
427 const char *
ld_get_env_var(int idx)428 ld_get_env_var(int idx)
429 {
430 return (ld_env_vars[idx].val);
431 }
432
433 static const char *
rtld_get_env_val(char ** env,const char * name,size_t name_len)434 rtld_get_env_val(char **env, const char *name, size_t name_len)
435 {
436 char **m, *n, *v;
437
438 for (m = env; *m != NULL; m++) {
439 n = *m;
440 v = strchr(n, '=');
441 if (v == NULL) {
442 /* corrupt environment? */
443 continue;
444 }
445 if (v - n == (ptrdiff_t)name_len &&
446 strncmp(name, n, name_len) == 0)
447 return (v + 1);
448 }
449 return (NULL);
450 }
451
452 static void
rtld_init_env_vars_for_prefix(char ** env,const char * env_prefix)453 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix)
454 {
455 struct ld_env_var_desc *lvd;
456 size_t prefix_len, nlen;
457 char **m, *n, *v;
458 int i;
459
460 prefix_len = strlen(env_prefix);
461 for (m = env; *m != NULL; m++) {
462 n = *m;
463 if (strncmp(env_prefix, n, prefix_len) != 0) {
464 /* Not a rtld environment variable. */
465 continue;
466 }
467 n += prefix_len;
468 v = strchr(n, '=');
469 if (v == NULL) {
470 /* corrupt environment? */
471 continue;
472 }
473 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
474 lvd = &ld_env_vars[i];
475 if (lvd->val != NULL) {
476 /* Saw higher-priority variable name already. */
477 continue;
478 }
479 nlen = strlen(lvd->n);
480 if (v - n == (ptrdiff_t)nlen &&
481 strncmp(lvd->n, n, nlen) == 0) {
482 lvd->val = v + 1;
483 break;
484 }
485 }
486 }
487 }
488
489 static void
rtld_init_env_vars(char ** env)490 rtld_init_env_vars(char **env)
491 {
492 rtld_init_env_vars_for_prefix(env, ld_env_prefix);
493 }
494
495 static void
set_ld_elf_hints_path(void)496 set_ld_elf_hints_path(void)
497 {
498 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0)
499 ld_elf_hints_path = ld_elf_hints_default;
500 }
501
502 uintptr_t
rtld_round_page(uintptr_t x)503 rtld_round_page(uintptr_t x)
504 {
505 return (roundup2(x, page_size));
506 }
507
508 uintptr_t
rtld_trunc_page(uintptr_t x)509 rtld_trunc_page(uintptr_t x)
510 {
511 return (rounddown2(x, page_size));
512 }
513
514 /*
515 * Main entry point for dynamic linking. The first argument is the
516 * stack pointer. The stack is expected to be laid out as described
517 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
518 * Specifically, the stack pointer points to a word containing
519 * ARGC. Following that in the stack is a null-terminated sequence
520 * of pointers to argument strings. Then comes a null-terminated
521 * sequence of pointers to environment strings. Finally, there is a
522 * sequence of "auxiliary vector" entries.
523 *
524 * The second argument points to a place to store the dynamic linker's
525 * exit procedure pointer and the third to a place to store the main
526 * program's object.
527 *
528 * The return value is the main program's entry point.
529 */
530 func_ptr_type
_rtld(Elf_Addr * sp,func_ptr_type * exit_proc,Obj_Entry ** objp)531 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
532 {
533 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT], auxtmp;
534 Objlist_Entry *entry;
535 Obj_Entry *last_interposer, *obj, *preload_tail;
536 const Elf_Phdr *phdr;
537 Objlist initlist;
538 RtldLockState lockstate;
539 struct stat st;
540 Elf_Addr *argcp;
541 char **argv, **env, **envp, *kexecpath;
542 const char *argv0, *binpath, *static_tls_extra;
543 struct ld_env_var_desc *lvd;
544 caddr_t imgentry;
545 char buf[MAXPATHLEN];
546 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc;
547 size_t sz;
548 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path;
549
550 /*
551 * On entry, the dynamic linker itself has not been relocated yet.
552 * Be very careful not to reference any global data until after
553 * init_rtld has returned. It is OK to reference file-scope statics
554 * and string constants, and to call static and global functions.
555 */
556
557 /* Find the auxiliary vector on the stack. */
558 argcp = sp;
559 argc = *sp++;
560 argv = (char **)sp;
561 sp += argc + 1; /* Skip over arguments and NULL terminator */
562 env = (char **)sp;
563 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
564 ;
565 aux = (Elf_Auxinfo *)sp;
566
567 /* Digest the auxiliary vector. */
568 for (i = 0; i < AT_COUNT; i++)
569 aux_info[i] = NULL;
570 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
571 if (auxp->a_type < AT_COUNT)
572 aux_info[auxp->a_type] = auxp;
573 }
574 arch_fix_auxv(aux, aux_info);
575
576 /* Initialize and relocate ourselves. */
577 assert(aux_info[AT_BASE] != NULL);
578 init_rtld((caddr_t)aux_info[AT_BASE]->a_un.a_ptr, aux_info);
579
580 dlerror_dflt_init();
581
582 __progname = obj_rtld.path;
583 argv0 = argv[0] != NULL ? argv[0] : "(null)";
584 environ = env;
585 main_argc = argc;
586 main_argv = argv;
587
588 if (aux_info[AT_BSDFLAGS] != NULL &&
589 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0)
590 ld_fast_sigblock = true;
591
592 trust = !issetugid();
593 direct_exec = false;
594
595 md_abi_variant_hook(aux_info);
596 rtld_init_env_vars(env);
597
598 fd = -1;
599 if (aux_info[AT_EXECFD] != NULL) {
600 fd = aux_info[AT_EXECFD]->a_un.a_val;
601 } else {
602 assert(aux_info[AT_PHDR] != NULL);
603 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
604 if (phdr == obj_rtld.phdr) {
605 if (!trust) {
606 _rtld_error(
607 "Tainted process refusing to run binary %s",
608 argv0);
609 rtld_die();
610 }
611 direct_exec = true;
612
613 dbg("opening main program in direct exec mode");
614 if (argc >= 2) {
615 rtld_argc = parse_args(argv, argc,
616 &search_in_path, &fd, &argv0, &dir_ignore);
617 explicit_fd = (fd != -1);
618 binpath = NULL;
619 if (!explicit_fd)
620 fd = open_binary_fd(argv0,
621 search_in_path, &binpath);
622 if (fstat(fd, &st) == -1) {
623 _rtld_error(
624 "Failed to fstat FD %d (%s): %s",
625 fd,
626 explicit_fd ?
627 "user-provided descriptor" :
628 argv0,
629 rtld_strerror(errno));
630 rtld_die();
631 }
632
633 /*
634 * Rough emulation of the permission checks done
635 * by execve(2), only Unix DACs are checked,
636 * ACLs are ignored. Preserve the semantic of
637 * disabling owner to execute if owner x bit is
638 * cleared, even if others x bit is enabled.
639 * mmap(2) does not allow to mmap with PROT_EXEC
640 * if binary' file comes from noexec mount. We
641 * cannot set a text reference on the binary.
642 */
643 dir_enable = false;
644 if (st.st_uid == geteuid()) {
645 if ((st.st_mode & S_IXUSR) != 0)
646 dir_enable = true;
647 } else if (st.st_gid == getegid()) {
648 if ((st.st_mode & S_IXGRP) != 0)
649 dir_enable = true;
650 } else if ((st.st_mode & S_IXOTH) != 0) {
651 dir_enable = true;
652 }
653 if (!dir_enable && !dir_ignore) {
654 _rtld_error(
655 "No execute permission for binary %s",
656 argv0);
657 rtld_die();
658 }
659
660 /*
661 * For direct exec mode, argv[0] is the
662 * interpreter name, we must remove it and shift
663 * arguments left before invoking binary main.
664 * Since stack layout places environment
665 * pointers and aux vectors right after the
666 * terminating NULL, we must shift environment
667 * and aux as well.
668 */
669 main_argc = argc - rtld_argc;
670 for (i = 0; i <= main_argc; i++)
671 argv[i] = argv[i + rtld_argc];
672 *argcp -= rtld_argc;
673 environ = env = envp = argv + main_argc + 1;
674 dbg("move env from %p to %p", envp + rtld_argc,
675 envp);
676 do {
677 *envp = *(envp + rtld_argc);
678 } while (*envp++ != NULL);
679 aux = auxp = (Elf_Auxinfo *)envp;
680 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
681 dbg("move aux from %p to %p", auxpf, aux);
682 /*
683 * XXXKIB insert place for AT_EXECPATH if not
684 * present
685 */
686 for (;; auxp++, auxpf++) {
687 /*
688 * NB: Use a temporary since *auxpf and
689 * *auxp overlap if rtld_argc is 1
690 */
691 auxtmp = *auxpf;
692 *auxp = auxtmp;
693 if (auxp->a_type == AT_NULL)
694 break;
695 }
696 /*
697 * Since the auxiliary vector has moved,
698 * redigest it.
699 */
700 for (i = 0; i < AT_COUNT; i++)
701 aux_info[i] = NULL;
702 for (auxp = aux; auxp->a_type != AT_NULL;
703 auxp++) {
704 if (auxp->a_type < AT_COUNT)
705 aux_info[auxp->a_type] = auxp;
706 }
707
708 /*
709 * Point AT_EXECPATH auxv and aux_info to the
710 * binary path.
711 */
712 if (binpath == NULL) {
713 aux_info[AT_EXECPATH] = NULL;
714 } else {
715 if (aux_info[AT_EXECPATH] == NULL) {
716 aux_info[AT_EXECPATH] = xmalloc(
717 sizeof(Elf_Auxinfo));
718 aux_info[AT_EXECPATH]->a_type =
719 AT_EXECPATH;
720 }
721 aux_info[AT_EXECPATH]->a_un.a_ptr =
722 __DECONST(void *, binpath);
723 }
724 } else {
725 _rtld_error("No binary");
726 rtld_die();
727 }
728 }
729 }
730
731 ld_bind_now = ld_get_env_var(LD_BIND_NOW);
732
733 /*
734 * If the process is tainted, then we un-set the dangerous environment
735 * variables. The process will be marked as tainted until setuid(2)
736 * is called. If any child process calls setuid(2) we do not want any
737 * future processes to honor the potentially un-safe variables.
738 */
739 if (!trust) {
740 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
741 lvd = &ld_env_vars[i];
742 if (lvd->unsecure)
743 lvd->val = NULL;
744 }
745 }
746
747 rtld_recalc_debug(ld_get_env_var(LD_DEBUG));
748 rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT));
749 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL;
750 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL;
751 libmap_override = ld_get_env_var(LD_LIBMAP);
752 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH);
753 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS);
754 ld_preload = ld_get_env_var(LD_PRELOAD);
755 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS);
756 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH);
757 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL;
758 rtld_recalc_path_rpath(ld_get_env_var(LD_LIBRARY_PATH_RPATH));
759 static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA);
760 if (static_tls_extra != NULL && static_tls_extra[0] != '\0') {
761 sz = parse_integer(static_tls_extra);
762 if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX)
763 ld_static_tls_extra = sz;
764 }
765 rtld_recalc_dangerous_ld_env();
766 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS);
767 ld_utrace = ld_get_env_var(LD_UTRACE);
768
769 set_ld_elf_hints_path();
770 dbg("%s is initialized, base address = %p", __progname,
771 (caddr_t)aux_info[AT_BASE]->a_un.a_ptr);
772 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
773 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
774
775 dbg("initializing thread locks");
776 lockdflt_init();
777
778 /*
779 * Load the main program, or process its program header if it is
780 * already loaded.
781 */
782 if (fd != -1) { /* Load the main program. */
783 dbg("loading main program");
784 obj_main = map_object(fd, argv0, NULL, true);
785 close(fd);
786 if (obj_main == NULL)
787 rtld_die();
788 max_stack_flags = obj_main->stack_flags;
789 } else { /* Main program already loaded. */
790 dbg("processing main program's program header");
791 assert(aux_info[AT_PHDR] != NULL);
792 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
793 assert(aux_info[AT_PHNUM] != NULL);
794 phnum = aux_info[AT_PHNUM]->a_un.a_val;
795 assert(aux_info[AT_PHENT] != NULL);
796 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
797 assert(aux_info[AT_ENTRY] != NULL);
798 imgentry = (caddr_t)aux_info[AT_ENTRY]->a_un.a_ptr;
799 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) ==
800 NULL)
801 rtld_die();
802 }
803
804 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
805 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
806 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
807 if (kexecpath[0] == '/')
808 obj_main->path = kexecpath;
809 else if (getcwd(buf, sizeof(buf)) == NULL ||
810 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
811 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
812 obj_main->path = xstrdup(argv0);
813 else
814 obj_main->path = xstrdup(buf);
815 } else {
816 dbg("No AT_EXECPATH or direct exec");
817 obj_main->path = xstrdup(argv0);
818 }
819 dbg("obj_main path %s", obj_main->path);
820 obj_main->mainprog = true;
821
822 if (aux_info[AT_STACKPROT] != NULL &&
823 aux_info[AT_STACKPROT]->a_un.a_val != 0)
824 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
825
826 #ifndef COMPAT_libcompat
827 /*
828 * Get the actual dynamic linker pathname from the executable if
829 * possible. (It should always be possible.) That ensures that
830 * gdb will find the right dynamic linker even if a non-standard
831 * one is being used.
832 */
833 if (obj_main->interp != NULL &&
834 strcmp(obj_main->interp, obj_rtld.path) != 0) {
835 free(obj_rtld.path);
836 obj_rtld.path = xstrdup(obj_main->interp);
837 __progname = obj_rtld.path;
838 }
839 #endif
840
841 if (!digest_dynamic(obj_main, 0))
842 rtld_die();
843 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
844 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
845 obj_main->dynsymcount);
846
847 linkmap_add(obj_main);
848 linkmap_add(&obj_rtld);
849 LD_UTRACE(UTRACE_LOAD_OBJECT, obj_main, obj_main->mapbase,
850 obj_main->mapsize, 0, obj_main->path);
851 LD_UTRACE(UTRACE_LOAD_OBJECT, &obj_rtld, obj_rtld.mapbase,
852 obj_rtld.mapsize, 0, obj_rtld.path);
853
854 /* Link the main program into the list of objects. */
855 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
856 obj_count++;
857 obj_loads++;
858
859 /* Initialize a fake symbol for resolving undefined weak references. */
860 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
861 sym_zero.st_shndx = SHN_UNDEF;
862 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
863
864 if (!libmap_disable)
865 libmap_disable = (bool)lm_init(libmap_override);
866
867 if (aux_info[AT_KPRELOAD] != NULL &&
868 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) {
869 dbg("loading kernel vdso");
870 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1)
871 rtld_die();
872 }
873
874 dbg("loading LD_PRELOAD_FDS libraries");
875 if (load_preload_objects(ld_preload_fds, true) == -1)
876 rtld_die();
877
878 dbg("loading LD_PRELOAD libraries");
879 if (load_preload_objects(ld_preload, false) == -1)
880 rtld_die();
881 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
882
883 dbg("loading needed objects");
884 if (load_needed_objects(obj_main,
885 ld_tracing != NULL ? RTLD_LO_TRACE : 0) == -1)
886 rtld_die();
887
888 /* Make a list of all objects loaded at startup. */
889 last_interposer = obj_main;
890 TAILQ_FOREACH(obj, &obj_list, next) {
891 if (obj->marker)
892 continue;
893 if (obj->z_interpose && obj != obj_main) {
894 objlist_put_after(&list_main, last_interposer, obj);
895 last_interposer = obj;
896 } else {
897 objlist_push_tail(&list_main, obj);
898 }
899 obj->refcount++;
900 }
901
902 dbg("checking for required versions");
903 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
904 rtld_die();
905
906 if (ld_get_env_var(LD_SHOW_AUXV) != NULL)
907 dump_auxv(aux_info);
908
909 if (ld_tracing) { /* We're done */
910 trace_loaded_objects(obj_main, true);
911 exit(0);
912 }
913
914 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) {
915 dump_relocations(obj_main);
916 exit(0);
917 }
918
919 /*
920 * Processing tls relocations requires having the tls offsets
921 * initialized. Prepare offsets before starting initial
922 * relocation processing.
923 */
924 dbg("initializing initial thread local storage offsets");
925 STAILQ_FOREACH(entry, &list_main, link) {
926 /*
927 * Allocate all the initial objects out of the static TLS
928 * block even if they didn't ask for it.
929 */
930 allocate_tls_offset(entry->obj);
931 }
932
933 if (!allocate_tls_offset_common(&tcb_list_entry_offset,
934 sizeof(struct tcb_list_entry), _Alignof(struct tcb_list_entry),
935 0)) {
936 /*
937 * This should be impossible as the static block size is not
938 * yet fixed, but catch and diagnose it failing if that ever
939 * changes or somehow turns out to be false.
940 */
941 _rtld_error("Could not allocate offset for tcb_list_entry");
942 rtld_die();
943 }
944 dbg("tcb_list_entry_offset %zu", tcb_list_entry_offset);
945
946 if (relocate_objects(obj_main,
947 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld,
948 SYMLOOK_EARLY, NULL) == -1)
949 rtld_die();
950
951 dbg("doing copy relocations");
952 if (do_copy_relocations(obj_main) == -1)
953 rtld_die();
954
955 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) {
956 dump_relocations(obj_main);
957 exit(0);
958 }
959
960 ifunc_init(aux_info);
961
962 /*
963 * Setup TLS for main thread. This must be done after the
964 * relocations are processed, since tls initialization section
965 * might be the subject for relocations.
966 */
967 dbg("initializing initial thread local storage");
968 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
969
970 dbg("initializing key program variables");
971 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
972 set_program_var("environ", env);
973 set_program_var("__elf_aux_vector", aux);
974
975 /* Make a list of init functions to call. */
976 objlist_init(&initlist);
977 initlist_for_loaded_obj(globallist_curr(TAILQ_FIRST(&obj_list)),
978 preload_tail, &initlist);
979
980 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
981
982 map_stacks_exec(NULL);
983
984 if (!obj_main->crt_no_init) {
985 /*
986 * Make sure we don't call the main program's init and fini
987 * functions for binaries linked with old crt1 which calls
988 * _init itself.
989 */
990 obj_main->init = obj_main->fini = 0;
991 obj_main->preinit_array = obj_main->init_array =
992 obj_main->fini_array = NULL;
993 }
994
995 if (direct_exec) {
996 /* Set osrel for direct-execed binary */
997 mib[0] = CTL_KERN;
998 mib[1] = KERN_PROC;
999 mib[2] = KERN_PROC_OSREL;
1000 mib[3] = getpid();
1001 osrel = obj_main->osrel;
1002 sz = sizeof(old_osrel);
1003 dbg("setting osrel to %d", osrel);
1004 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
1005 }
1006
1007 wlock_acquire(rtld_bind_lock, &lockstate);
1008
1009 dbg("resolving ifuncs");
1010 if (initlist_objects_ifunc(&initlist,
1011 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
1012 &lockstate) == -1)
1013 rtld_die();
1014
1015 rtld_exit_ptr = rtld_exit;
1016 if (obj_main->crt_no_init)
1017 preinit_main();
1018 objlist_call_init(&initlist, &lockstate);
1019 _r_debug_postinit(&obj_main->linkmap);
1020 objlist_clear(&initlist);
1021 dbg("loading filtees");
1022 TAILQ_FOREACH(obj, &obj_list, next) {
1023 if (obj->marker)
1024 continue;
1025 if (ld_loadfltr || obj->z_loadfltr)
1026 load_filtees(obj, 0, &lockstate);
1027 }
1028
1029 dbg("enforcing main obj relro");
1030 if (obj_enforce_relro(obj_main) == -1)
1031 rtld_die();
1032
1033 lock_release(rtld_bind_lock, &lockstate);
1034
1035 dbg("transferring control to program entry point = %p",
1036 obj_main->entry);
1037
1038 /* Return the exit procedure and the program entry point. */
1039 *exit_proc = rtld_exit_ptr;
1040 *objp = obj_main;
1041 return ((func_ptr_type)obj_main->entry);
1042 }
1043
1044 void *
rtld_resolve_ifunc(const Obj_Entry * obj,const Elf_Sym * def)1045 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
1046 {
1047 void *ptr;
1048 Elf_Addr target;
1049
1050 ptr = (void *)make_function_pointer(def, obj);
1051 target = call_ifunc_resolver(ptr);
1052 return ((void *)target);
1053 }
1054
1055 Elf_Addr
_rtld_bind(Obj_Entry * obj,Elf_Size reloff)1056 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
1057 {
1058 const Elf_Rel *rel;
1059 const Elf_Sym *def;
1060 const Obj_Entry *defobj;
1061 Elf_Addr *where;
1062 Elf_Addr target;
1063 RtldLockState lockstate;
1064
1065 relock:
1066 rlock_acquire(rtld_bind_lock, &lockstate);
1067 if (sigsetjmp(lockstate.env, 0) != 0)
1068 lock_upgrade(rtld_bind_lock, &lockstate);
1069 if (obj->pltrel)
1070 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
1071 else
1072 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
1073
1074 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
1075 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
1076 NULL, &lockstate);
1077 if (def == NULL)
1078 rtld_die();
1079 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) {
1080 if (lockstate_wlocked(&lockstate)) {
1081 lock_release(rtld_bind_lock, &lockstate);
1082 goto relock;
1083 }
1084 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
1085 } else {
1086 target = (Elf_Addr)(defobj->relocbase + def->st_value);
1087 }
1088
1089 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", defobj->strtab + def->st_name,
1090 obj->path == NULL ? NULL : basename(obj->path), (void *)target,
1091 defobj->path == NULL ? NULL : basename(defobj->path));
1092
1093 /*
1094 * Write the new contents for the jmpslot. Note that depending on
1095 * architecture, the value which we need to return back to the
1096 * lazy binding trampoline may or may not be the target
1097 * address. The value returned from reloc_jmpslot() is the value
1098 * that the trampoline needs.
1099 */
1100 target = reloc_jmpslot(where, target, defobj, obj, rel);
1101 lock_release(rtld_bind_lock, &lockstate);
1102 return (target);
1103 }
1104
1105 /*
1106 * Error reporting function. Use it like printf. If formats the message
1107 * into a buffer, and sets things up so that the next call to dlerror()
1108 * will return the message.
1109 */
1110 void
_rtld_error(const char * fmt,...)1111 _rtld_error(const char *fmt, ...)
1112 {
1113 va_list ap;
1114
1115 va_start(ap, fmt);
1116 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, fmt,
1117 ap);
1118 va_end(ap);
1119 *lockinfo.dlerror_seen() = 0;
1120 dbg("rtld_error: %s", lockinfo.dlerror_loc());
1121 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc());
1122 }
1123
1124 /*
1125 * Return a dynamically-allocated copy of the current error message, if any.
1126 */
1127 static struct dlerror_save *
errmsg_save(void)1128 errmsg_save(void)
1129 {
1130 struct dlerror_save *res;
1131
1132 res = xmalloc(sizeof(*res));
1133 res->seen = *lockinfo.dlerror_seen();
1134 if (res->seen == 0)
1135 res->msg = xstrdup(lockinfo.dlerror_loc());
1136 return (res);
1137 }
1138
1139 /*
1140 * Restore the current error message from a copy which was previously saved
1141 * by errmsg_save(). The copy is freed.
1142 */
1143 static void
errmsg_restore(struct dlerror_save * saved_msg)1144 errmsg_restore(struct dlerror_save *saved_msg)
1145 {
1146 if (saved_msg == NULL || saved_msg->seen == 1) {
1147 *lockinfo.dlerror_seen() = 1;
1148 } else {
1149 *lockinfo.dlerror_seen() = 0;
1150 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg,
1151 lockinfo.dlerror_loc_sz);
1152 free(saved_msg->msg);
1153 }
1154 free(saved_msg);
1155 }
1156
1157 static const char *
basename(const char * name)1158 basename(const char *name)
1159 {
1160 const char *p;
1161
1162 p = strrchr(name, '/');
1163 return (p != NULL ? p + 1 : name);
1164 }
1165
1166 static struct utsname uts;
1167
1168 static char *
origin_subst_one(Obj_Entry * obj,char * real,const char * kw,const char * subst,bool may_free)1169 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, const char *subst,
1170 bool may_free)
1171 {
1172 char *p, *p1, *res, *resp;
1173 int subst_len, kw_len, subst_count, old_len, new_len;
1174
1175 kw_len = strlen(kw);
1176
1177 /*
1178 * First, count the number of the keyword occurrences, to
1179 * preallocate the final string.
1180 */
1181 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
1182 p1 = strstr(p, kw);
1183 if (p1 == NULL)
1184 break;
1185 }
1186
1187 /*
1188 * If the keyword is not found, just return.
1189 *
1190 * Return non-substituted string if resolution failed. We
1191 * cannot do anything more reasonable, the failure mode of the
1192 * caller is unresolved library anyway.
1193 */
1194 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
1195 return (may_free ? real : xstrdup(real));
1196 if (obj != NULL)
1197 subst = obj->origin_path;
1198
1199 /*
1200 * There is indeed something to substitute. Calculate the
1201 * length of the resulting string, and allocate it.
1202 */
1203 subst_len = strlen(subst);
1204 old_len = strlen(real);
1205 new_len = old_len + (subst_len - kw_len) * subst_count;
1206 res = xmalloc(new_len + 1);
1207
1208 /*
1209 * Now, execute the substitution loop.
1210 */
1211 for (p = real, resp = res, *resp = '\0';;) {
1212 p1 = strstr(p, kw);
1213 if (p1 != NULL) {
1214 /* Copy the prefix before keyword. */
1215 memcpy(resp, p, p1 - p);
1216 resp += p1 - p;
1217 /* Keyword replacement. */
1218 memcpy(resp, subst, subst_len);
1219 resp += subst_len;
1220 *resp = '\0';
1221 p = p1 + kw_len;
1222 } else
1223 break;
1224 }
1225
1226 /* Copy to the end of string and finish. */
1227 strcat(resp, p);
1228 if (may_free)
1229 free(real);
1230 return (res);
1231 }
1232
1233 static const struct {
1234 const char *kw;
1235 bool pass_obj;
1236 const char *subst;
1237 } tokens[] = {
1238 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL },
1239 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL },
1240 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname },
1241 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname },
1242 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release },
1243 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release },
1244 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine },
1245 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine },
1246 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB },
1247 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB },
1248 };
1249
1250 static char *
origin_subst(Obj_Entry * obj,const char * real)1251 origin_subst(Obj_Entry *obj, const char *real)
1252 {
1253 char *res;
1254 int i;
1255
1256 if (obj == NULL || !trust)
1257 return (xstrdup(real));
1258 if (uts.sysname[0] == '\0') {
1259 if (uname(&uts) != 0) {
1260 _rtld_error("utsname failed: %d", errno);
1261 return (NULL);
1262 }
1263 }
1264
1265 /* __DECONST is safe here since without may_free real is unchanged */
1266 res = __DECONST(char *, real);
1267 for (i = 0; i < (int)nitems(tokens); i++) {
1268 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, res,
1269 tokens[i].kw, tokens[i].subst, i != 0);
1270 }
1271 return (res);
1272 }
1273
1274 void
rtld_die(void)1275 rtld_die(void)
1276 {
1277 const char *msg = dlerror();
1278
1279 if (msg == NULL)
1280 msg = "Fatal error";
1281 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1282 rtld_fdputstr(STDERR_FILENO, msg);
1283 rtld_fdputchar(STDERR_FILENO, '\n');
1284 _exit(1);
1285 }
1286
1287 /*
1288 * Process a shared object's DYNAMIC section, and save the important
1289 * information in its Obj_Entry structure.
1290 */
1291 static void
digest_dynamic1(Obj_Entry * obj,int early,const Elf_Dyn ** dyn_rpath,const Elf_Dyn ** dyn_soname,const Elf_Dyn ** dyn_runpath)1292 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1293 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1294 {
1295 const Elf_Dyn *dynp;
1296 Needed_Entry **needed_tail = &obj->needed;
1297 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1298 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1299 const Elf_Hashelt *hashtab;
1300 const Elf32_Word *hashval;
1301 Elf32_Word bkt, nmaskwords;
1302 int bloom_size32;
1303 int plttype = DT_REL;
1304
1305 *dyn_rpath = NULL;
1306 *dyn_soname = NULL;
1307 *dyn_runpath = NULL;
1308
1309 obj->bind_now = false;
1310 dynp = obj->dynamic;
1311 if (dynp == NULL)
1312 return;
1313 for (; dynp->d_tag != DT_NULL; dynp++) {
1314 switch (dynp->d_tag) {
1315 case DT_REL:
1316 obj->rel = (const Elf_Rel *)(obj->relocbase +
1317 dynp->d_un.d_ptr);
1318 break;
1319
1320 case DT_RELSZ:
1321 obj->relsize = dynp->d_un.d_val;
1322 break;
1323
1324 case DT_RELENT:
1325 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1326 break;
1327
1328 case DT_JMPREL:
1329 obj->pltrel = (const Elf_Rel *)(obj->relocbase +
1330 dynp->d_un.d_ptr);
1331 break;
1332
1333 case DT_PLTRELSZ:
1334 obj->pltrelsize = dynp->d_un.d_val;
1335 break;
1336
1337 case DT_RELA:
1338 obj->rela = (const Elf_Rela *)(obj->relocbase +
1339 dynp->d_un.d_ptr);
1340 break;
1341
1342 case DT_RELASZ:
1343 obj->relasize = dynp->d_un.d_val;
1344 break;
1345
1346 case DT_RELAENT:
1347 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1348 break;
1349
1350 case DT_RELR:
1351 obj->relr = (const Elf_Relr *)(obj->relocbase +
1352 dynp->d_un.d_ptr);
1353 break;
1354
1355 case DT_RELRSZ:
1356 obj->relrsize = dynp->d_un.d_val;
1357 break;
1358
1359 case DT_RELRENT:
1360 assert(dynp->d_un.d_val == sizeof(Elf_Relr));
1361 break;
1362
1363 case DT_PLTREL:
1364 plttype = dynp->d_un.d_val;
1365 assert(
1366 dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1367 break;
1368
1369 case DT_SYMTAB:
1370 obj->symtab = (const Elf_Sym *)(obj->relocbase +
1371 dynp->d_un.d_ptr);
1372 break;
1373
1374 case DT_SYMENT:
1375 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1376 break;
1377
1378 case DT_STRTAB:
1379 obj->strtab = (const char *)(obj->relocbase +
1380 dynp->d_un.d_ptr);
1381 break;
1382
1383 case DT_STRSZ:
1384 obj->strsize = dynp->d_un.d_val;
1385 break;
1386
1387 case DT_VERNEED:
1388 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1389 dynp->d_un.d_val);
1390 break;
1391
1392 case DT_VERNEEDNUM:
1393 obj->verneednum = dynp->d_un.d_val;
1394 break;
1395
1396 case DT_VERDEF:
1397 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1398 dynp->d_un.d_val);
1399 break;
1400
1401 case DT_VERDEFNUM:
1402 obj->verdefnum = dynp->d_un.d_val;
1403 break;
1404
1405 case DT_VERSYM:
1406 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1407 dynp->d_un.d_val);
1408 break;
1409
1410 case DT_HASH: {
1411 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1412 dynp->d_un.d_ptr);
1413 obj->nbuckets = hashtab[0];
1414 obj->nchains = hashtab[1];
1415 obj->buckets = hashtab + 2;
1416 obj->chains = obj->buckets + obj->nbuckets;
1417 obj->valid_hash_sysv = obj->nbuckets > 0 &&
1418 obj->nchains > 0 && obj->buckets != NULL;
1419 } break;
1420
1421 case DT_GNU_HASH: {
1422 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1423 dynp->d_un.d_ptr);
1424 obj->nbuckets_gnu = hashtab[0];
1425 obj->symndx_gnu = hashtab[1];
1426 nmaskwords = hashtab[2];
1427 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1428 obj->maskwords_bm_gnu = nmaskwords - 1;
1429 obj->shift2_gnu = hashtab[3];
1430 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1431 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1432 obj->chain_zero_gnu = obj->buckets_gnu +
1433 obj->nbuckets_gnu - obj->symndx_gnu;
1434 /* Number of bitmask words is required to be power of 2
1435 */
1436 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1437 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1438 } break;
1439
1440 case DT_NEEDED:
1441 if (!obj->rtld) {
1442 Needed_Entry *nep = NEW(Needed_Entry);
1443 nep->name = dynp->d_un.d_val;
1444 nep->obj = NULL;
1445 nep->next = NULL;
1446
1447 *needed_tail = nep;
1448 needed_tail = &nep->next;
1449 }
1450 break;
1451
1452 case DT_FILTER:
1453 if (!obj->rtld) {
1454 Needed_Entry *nep = NEW(Needed_Entry);
1455 nep->name = dynp->d_un.d_val;
1456 nep->obj = NULL;
1457 nep->next = NULL;
1458
1459 *needed_filtees_tail = nep;
1460 needed_filtees_tail = &nep->next;
1461
1462 if (obj->linkmap.l_refname == NULL)
1463 obj->linkmap.l_refname =
1464 (char *)dynp->d_un.d_val;
1465 }
1466 break;
1467
1468 case DT_AUXILIARY:
1469 if (!obj->rtld) {
1470 Needed_Entry *nep = NEW(Needed_Entry);
1471 nep->name = dynp->d_un.d_val;
1472 nep->obj = NULL;
1473 nep->next = NULL;
1474
1475 *needed_aux_filtees_tail = nep;
1476 needed_aux_filtees_tail = &nep->next;
1477 }
1478 break;
1479
1480 case DT_PLTGOT:
1481 obj->pltgot = (Elf_Addr *)(obj->relocbase +
1482 dynp->d_un.d_ptr);
1483 break;
1484
1485 case DT_TEXTREL:
1486 obj->textrel = true;
1487 break;
1488
1489 case DT_SYMBOLIC:
1490 obj->symbolic = true;
1491 break;
1492
1493 case DT_RPATH:
1494 /*
1495 * We have to wait until later to process this, because
1496 * we might not have gotten the address of the string
1497 * table yet.
1498 */
1499 *dyn_rpath = dynp;
1500 break;
1501
1502 case DT_SONAME:
1503 *dyn_soname = dynp;
1504 break;
1505
1506 case DT_RUNPATH:
1507 *dyn_runpath = dynp;
1508 break;
1509
1510 case DT_INIT:
1511 obj->init = (uintptr_t)(obj->relocbase +
1512 dynp->d_un.d_ptr);
1513 break;
1514
1515 case DT_PREINIT_ARRAY:
1516 obj->preinit_array = (uintptr_t *)(obj->relocbase +
1517 dynp->d_un.d_ptr);
1518 break;
1519
1520 case DT_PREINIT_ARRAYSZ:
1521 obj->preinit_array_num = dynp->d_un.d_val /
1522 sizeof(uintptr_t);
1523 break;
1524
1525 case DT_INIT_ARRAY:
1526 obj->init_array = (uintptr_t *)(obj->relocbase +
1527 dynp->d_un.d_ptr);
1528 break;
1529
1530 case DT_INIT_ARRAYSZ:
1531 obj->init_array_num = dynp->d_un.d_val /
1532 sizeof(uintptr_t);
1533 break;
1534
1535 case DT_FINI:
1536 obj->fini = (uintptr_t)(obj->relocbase +
1537 dynp->d_un.d_ptr);
1538 break;
1539
1540 case DT_FINI_ARRAY:
1541 obj->fini_array = (uintptr_t *)(obj->relocbase +
1542 dynp->d_un.d_ptr);
1543 break;
1544
1545 case DT_FINI_ARRAYSZ:
1546 obj->fini_array_num = dynp->d_un.d_val /
1547 sizeof(uintptr_t);
1548 break;
1549
1550 case DT_DEBUG:
1551 if (!early)
1552 dbg("Filling in DT_DEBUG entry");
1553 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr =
1554 (Elf_Addr)&r_debug;
1555 break;
1556
1557 case DT_FLAGS:
1558 if (dynp->d_un.d_val & DF_ORIGIN)
1559 obj->z_origin = true;
1560 if (dynp->d_un.d_val & DF_SYMBOLIC)
1561 obj->symbolic = true;
1562 if (dynp->d_un.d_val & DF_TEXTREL)
1563 obj->textrel = true;
1564 if (dynp->d_un.d_val & DF_BIND_NOW)
1565 obj->bind_now = true;
1566 if (dynp->d_un.d_val & DF_STATIC_TLS)
1567 obj->static_tls = true;
1568 break;
1569
1570 case DT_FLAGS_1:
1571 if (dynp->d_un.d_val & DF_1_NOOPEN)
1572 obj->z_noopen = true;
1573 if (dynp->d_un.d_val & DF_1_ORIGIN)
1574 obj->z_origin = true;
1575 if (dynp->d_un.d_val & DF_1_GLOBAL)
1576 obj->z_global = true;
1577 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1578 obj->bind_now = true;
1579 if (dynp->d_un.d_val & DF_1_NODELETE)
1580 obj->z_nodelete = true;
1581 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1582 obj->z_loadfltr = true;
1583 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1584 obj->z_interpose = true;
1585 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1586 obj->z_nodeflib = true;
1587 if (dynp->d_un.d_val & DF_1_PIE)
1588 obj->z_pie = true;
1589 if (dynp->d_un.d_val & DF_1_INITFIRST)
1590 obj->z_initfirst = true;
1591 break;
1592
1593 default:
1594 if (arch_digest_dynamic(obj, dynp))
1595 break;
1596
1597 if (!early) {
1598 dbg("Ignoring d_tag %ld = %#lx",
1599 (long)dynp->d_tag, (long)dynp->d_tag);
1600 }
1601 break;
1602 }
1603 }
1604
1605 obj->traced = false;
1606
1607 if (plttype == DT_RELA) {
1608 obj->pltrela = (const Elf_Rela *)obj->pltrel;
1609 obj->pltrel = NULL;
1610 obj->pltrelasize = obj->pltrelsize;
1611 obj->pltrelsize = 0;
1612 }
1613
1614 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1615 if (obj->valid_hash_sysv)
1616 obj->dynsymcount = obj->nchains;
1617 else if (obj->valid_hash_gnu) {
1618 obj->dynsymcount = 0;
1619 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1620 if (obj->buckets_gnu[bkt] == 0)
1621 continue;
1622 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1623 do
1624 obj->dynsymcount++;
1625 while ((*hashval++ & 1u) == 0);
1626 }
1627 obj->dynsymcount += obj->symndx_gnu;
1628 }
1629
1630 if (obj->linkmap.l_refname != NULL)
1631 obj->linkmap.l_refname = obj->strtab +
1632 (unsigned long)obj->linkmap.l_refname;
1633 }
1634
1635 static bool
obj_resolve_origin(Obj_Entry * obj)1636 obj_resolve_origin(Obj_Entry *obj)
1637 {
1638 if (obj->origin_path != NULL)
1639 return (true);
1640 obj->origin_path = xmalloc(PATH_MAX);
1641 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1642 }
1643
1644 static bool
digest_dynamic2(Obj_Entry * obj,const Elf_Dyn * dyn_rpath,const Elf_Dyn * dyn_soname,const Elf_Dyn * dyn_runpath)1645 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1646 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1647 {
1648 if (obj->z_origin && !obj_resolve_origin(obj))
1649 return (false);
1650
1651 if (dyn_runpath != NULL) {
1652 obj->runpath = (const char *)obj->strtab +
1653 dyn_runpath->d_un.d_val;
1654 obj->runpath = origin_subst(obj, obj->runpath);
1655 } else if (dyn_rpath != NULL) {
1656 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1657 obj->rpath = origin_subst(obj, obj->rpath);
1658 }
1659 if (dyn_soname != NULL)
1660 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1661 return (true);
1662 }
1663
1664 static bool
digest_dynamic(Obj_Entry * obj,int early)1665 digest_dynamic(Obj_Entry *obj, int early)
1666 {
1667 const Elf_Dyn *dyn_rpath;
1668 const Elf_Dyn *dyn_soname;
1669 const Elf_Dyn *dyn_runpath;
1670
1671 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1672 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1673 }
1674
1675 /*
1676 * Process a shared object's program header. This is used only for the
1677 * main program, when the kernel has already loaded the main program
1678 * into memory before calling the dynamic linker. It creates and
1679 * returns an Obj_Entry structure.
1680 */
1681 static Obj_Entry *
digest_phdr(const Elf_Phdr * phdr,int phnum,caddr_t entry,const char * path)1682 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1683 {
1684 Obj_Entry *obj;
1685 const Elf_Phdr *phlimit = phdr + phnum;
1686 const Elf_Phdr *ph;
1687 Elf_Addr note_start, note_end;
1688 int nsegs = 0;
1689
1690 obj = obj_new();
1691 for (ph = phdr; ph < phlimit; ph++) {
1692 if (ph->p_type != PT_PHDR)
1693 continue;
1694
1695 obj->phdr = phdr;
1696 obj->phnum = ph->p_memsz / sizeof(*ph);
1697 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1698 break;
1699 }
1700
1701 obj->stack_flags = PF_X | PF_R | PF_W;
1702
1703 for (ph = phdr; ph < phlimit; ph++) {
1704 switch (ph->p_type) {
1705 case PT_INTERP:
1706 obj->interp = (const char *)(ph->p_vaddr +
1707 obj->relocbase);
1708 break;
1709
1710 case PT_LOAD:
1711 if (nsegs == 0) { /* First load segment */
1712 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr);
1713 obj->mapbase = obj->vaddrbase + obj->relocbase;
1714 } else { /* Last load segment */
1715 obj->mapsize = rtld_round_page(
1716 ph->p_vaddr + ph->p_memsz) -
1717 obj->vaddrbase;
1718 }
1719 nsegs++;
1720 break;
1721
1722 case PT_DYNAMIC:
1723 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr +
1724 obj->relocbase);
1725 break;
1726
1727 case PT_TLS:
1728 obj->tlsindex = 1;
1729 obj->tlssize = ph->p_memsz;
1730 obj->tlsalign = ph->p_align;
1731 obj->tlsinitsize = ph->p_filesz;
1732 obj->tlsinit = (void *)(ph->p_vaddr + obj->relocbase);
1733 obj->tlspoffset = ph->p_offset;
1734 break;
1735
1736 case PT_GNU_STACK:
1737 obj->stack_flags = ph->p_flags;
1738 break;
1739
1740 case PT_NOTE:
1741 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1742 note_end = note_start + ph->p_filesz;
1743 digest_notes(obj, note_start, note_end);
1744 break;
1745 }
1746 }
1747 if (nsegs < 1) {
1748 _rtld_error("%s: too few PT_LOAD segments", path);
1749 return (NULL);
1750 }
1751
1752 obj->entry = entry;
1753 return (obj);
1754 }
1755
1756 void
digest_notes(Obj_Entry * obj,Elf_Addr note_start,Elf_Addr note_end)1757 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1758 {
1759 const Elf_Note *note;
1760 const char *note_name;
1761 uintptr_t p;
1762
1763 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1764 note = (const Elf_Note *)((const char *)(note + 1) +
1765 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1766 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1767 if (arch_digest_note(obj, note))
1768 continue;
1769
1770 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1771 note->n_descsz != sizeof(int32_t))
1772 continue;
1773 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1774 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1775 note->n_type != NT_FREEBSD_NOINIT_TAG)
1776 continue;
1777 note_name = (const char *)(note + 1);
1778 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1779 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1780 continue;
1781 switch (note->n_type) {
1782 case NT_FREEBSD_ABI_TAG:
1783 /* FreeBSD osrel note */
1784 p = (uintptr_t)(note + 1);
1785 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1786 obj->osrel = *(const int32_t *)(p);
1787 dbg("note osrel %d", obj->osrel);
1788 break;
1789 case NT_FREEBSD_FEATURE_CTL:
1790 /* FreeBSD ABI feature control note */
1791 p = (uintptr_t)(note + 1);
1792 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1793 obj->fctl0 = *(const uint32_t *)(p);
1794 dbg("note fctl0 %#x", obj->fctl0);
1795 break;
1796 case NT_FREEBSD_NOINIT_TAG:
1797 /* FreeBSD 'crt does not call init' note */
1798 obj->crt_no_init = true;
1799 dbg("note crt_no_init");
1800 break;
1801 }
1802 }
1803 }
1804
1805 static Obj_Entry *
dlcheck(void * handle)1806 dlcheck(void *handle)
1807 {
1808 Obj_Entry *obj;
1809
1810 TAILQ_FOREACH(obj, &obj_list, next) {
1811 if (obj == (Obj_Entry *)handle)
1812 break;
1813 }
1814
1815 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1816 _rtld_error("Invalid shared object handle %p", handle);
1817 return (NULL);
1818 }
1819 return (obj);
1820 }
1821
1822 /*
1823 * If the given object is already in the donelist, return true. Otherwise
1824 * add the object to the list and return false.
1825 */
1826 static bool
donelist_check(DoneList * dlp,const Obj_Entry * obj)1827 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1828 {
1829 unsigned int i;
1830
1831 for (i = 0; i < dlp->num_used; i++)
1832 if (dlp->objs[i] == obj)
1833 return (true);
1834 /*
1835 * Our donelist allocation should always be sufficient. But if
1836 * our threads locking isn't working properly, more shared objects
1837 * could have been loaded since we allocated the list. That should
1838 * never happen, but we'll handle it properly just in case it does.
1839 */
1840 if (dlp->num_used < dlp->num_alloc)
1841 dlp->objs[dlp->num_used++] = obj;
1842 return (false);
1843 }
1844
1845 /*
1846 * SysV hash function for symbol table lookup. It is a slightly optimized
1847 * version of the hash specified by the System V ABI.
1848 */
1849 Elf32_Word
elf_hash(const char * name)1850 elf_hash(const char *name)
1851 {
1852 const unsigned char *p = (const unsigned char *)name;
1853 Elf32_Word h = 0;
1854
1855 while (*p != '\0') {
1856 h = (h << 4) + *p++;
1857 h ^= (h >> 24) & 0xf0;
1858 }
1859 return (h & 0x0fffffff);
1860 }
1861
1862 /*
1863 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1864 * unsigned in case it's implemented with a wider type.
1865 */
1866 static uint32_t
gnu_hash(const char * s)1867 gnu_hash(const char *s)
1868 {
1869 uint32_t h;
1870 unsigned char c;
1871
1872 h = 5381;
1873 for (c = *s; c != '\0'; c = *++s)
1874 h = h * 33 + c;
1875 return (h & 0xffffffff);
1876 }
1877
1878 /*
1879 * Find the library with the given name, and return its full pathname.
1880 * The returned string is dynamically allocated. Generates an error
1881 * message and returns NULL if the library cannot be found.
1882 *
1883 * If the second argument is non-NULL, then it refers to an already-
1884 * loaded shared object, whose library search path will be searched.
1885 *
1886 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1887 * descriptor (which is close-on-exec) will be passed out via the third
1888 * argument.
1889 *
1890 * The search order is:
1891 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1892 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1893 * LD_LIBRARY_PATH
1894 * DT_RUNPATH in the referencing file
1895 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1896 * from list)
1897 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1898 *
1899 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1900 */
1901 static char *
find_library(const char * xname,const Obj_Entry * refobj,int * fdp)1902 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1903 {
1904 char *pathname, *refobj_path;
1905 const char *name;
1906 bool nodeflib, objgiven;
1907
1908 objgiven = refobj != NULL;
1909
1910 if (libmap_disable || !objgiven ||
1911 (name = lm_find(refobj->path, xname)) == NULL)
1912 name = xname;
1913
1914 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1915 if (name[0] != '/' && !trust) {
1916 _rtld_error(
1917 "Absolute pathname required for shared object \"%s\"",
1918 name);
1919 return (NULL);
1920 }
1921 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1922 __DECONST(char *, name)));
1923 }
1924
1925 dbg(" Searching for \"%s\"", name);
1926 refobj_path = objgiven ? refobj->path : NULL;
1927
1928 /*
1929 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1930 * back to pre-conforming behaviour if user requested so with
1931 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1932 * nodeflib.
1933 */
1934 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1935 pathname = search_library_path(name, ld_library_path,
1936 refobj_path, fdp);
1937 if (pathname != NULL)
1938 return (pathname);
1939 if (refobj != NULL) {
1940 pathname = search_library_path(name, refobj->rpath,
1941 refobj_path, fdp);
1942 if (pathname != NULL)
1943 return (pathname);
1944 }
1945 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1946 if (pathname != NULL)
1947 return (pathname);
1948 pathname = search_library_path(name, gethints(false),
1949 refobj_path, fdp);
1950 if (pathname != NULL)
1951 return (pathname);
1952 pathname = search_library_path(name, ld_standard_library_path,
1953 refobj_path, fdp);
1954 if (pathname != NULL)
1955 return (pathname);
1956 } else {
1957 nodeflib = objgiven ? refobj->z_nodeflib : false;
1958 if (objgiven) {
1959 pathname = search_library_path(name, refobj->rpath,
1960 refobj->path, fdp);
1961 if (pathname != NULL)
1962 return (pathname);
1963 }
1964 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1965 pathname = search_library_path(name, obj_main->rpath,
1966 refobj_path, fdp);
1967 if (pathname != NULL)
1968 return (pathname);
1969 }
1970 pathname = search_library_path(name, ld_library_path,
1971 refobj_path, fdp);
1972 if (pathname != NULL)
1973 return (pathname);
1974 if (objgiven) {
1975 pathname = search_library_path(name, refobj->runpath,
1976 refobj_path, fdp);
1977 if (pathname != NULL)
1978 return (pathname);
1979 }
1980 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1981 if (pathname != NULL)
1982 return (pathname);
1983 pathname = search_library_path(name, gethints(nodeflib),
1984 refobj_path, fdp);
1985 if (pathname != NULL)
1986 return (pathname);
1987 if (objgiven && !nodeflib) {
1988 pathname = search_library_path(name,
1989 ld_standard_library_path, refobj_path, fdp);
1990 if (pathname != NULL)
1991 return (pathname);
1992 }
1993 }
1994
1995 if (objgiven && refobj->path != NULL) {
1996 _rtld_error(
1997 "Shared object \"%s\" not found, required by \"%s\"",
1998 name, basename(refobj->path));
1999 } else {
2000 _rtld_error("Shared object \"%s\" not found", name);
2001 }
2002 return (NULL);
2003 }
2004
2005 /*
2006 * Given a symbol number in a referencing object, find the corresponding
2007 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2008 * no definition was found. Returns a pointer to the Obj_Entry of the
2009 * defining object via the reference parameter DEFOBJ_OUT.
2010 */
2011 const Elf_Sym *
find_symdef(unsigned long symnum,const Obj_Entry * refobj,const Obj_Entry ** defobj_out,int flags,SymCache * cache,RtldLockState * lockstate)2012 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
2013 const Obj_Entry **defobj_out, int flags, SymCache *cache,
2014 RtldLockState *lockstate)
2015 {
2016 const Elf_Sym *ref;
2017 const Elf_Sym *def;
2018 const Obj_Entry *defobj;
2019 const Ver_Entry *ve;
2020 SymLook req;
2021 const char *name;
2022 int res;
2023
2024 /*
2025 * If we have already found this symbol, get the information from
2026 * the cache.
2027 */
2028 if (symnum >= refobj->dynsymcount)
2029 return (NULL); /* Bad object */
2030 if (cache != NULL && cache[symnum].sym != NULL) {
2031 *defobj_out = cache[symnum].obj;
2032 return (cache[symnum].sym);
2033 }
2034
2035 ref = refobj->symtab + symnum;
2036 name = refobj->strtab + ref->st_name;
2037 def = NULL;
2038 defobj = NULL;
2039 ve = NULL;
2040
2041 /*
2042 * We don't have to do a full scale lookup if the symbol is local.
2043 * We know it will bind to the instance in this load module; to
2044 * which we already have a pointer (ie ref). By not doing a lookup,
2045 * we not only improve performance, but it also avoids unresolvable
2046 * symbols when local symbols are not in the hash table. This has
2047 * been seen with the ia64 toolchain.
2048 */
2049 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
2050 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
2051 _rtld_error("%s: Bogus symbol table entry %lu",
2052 refobj->path, symnum);
2053 }
2054 symlook_init(&req, name);
2055 req.flags = flags;
2056 ve = req.ventry = fetch_ventry(refobj, symnum);
2057 req.lockstate = lockstate;
2058 res = symlook_default(&req, refobj);
2059 if (res == 0) {
2060 def = req.sym_out;
2061 defobj = req.defobj_out;
2062 }
2063 } else {
2064 def = ref;
2065 defobj = refobj;
2066 }
2067
2068 /*
2069 * If we found no definition and the reference is weak, treat the
2070 * symbol as having the value zero.
2071 */
2072 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
2073 def = &sym_zero;
2074 defobj = obj_main;
2075 }
2076
2077 if (def != NULL) {
2078 *defobj_out = defobj;
2079 /*
2080 * Record the information in the cache to avoid subsequent
2081 * lookups.
2082 */
2083 if (cache != NULL) {
2084 cache[symnum].sym = def;
2085 cache[symnum].obj = defobj;
2086 }
2087 } else {
2088 if (refobj != &obj_rtld)
2089 _rtld_error("%s: Undefined symbol \"%s%s%s\"",
2090 refobj->path, name, ve != NULL ? "@" : "",
2091 ve != NULL ? ve->name : "");
2092 }
2093 return (def);
2094 }
2095
2096 /* Convert between native byte order and forced little resp. big endian. */
2097 #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n))
2098
2099 /*
2100 * Return the search path from the ldconfig hints file, reading it if
2101 * necessary. If nostdlib is true, then the default search paths are
2102 * not added to result.
2103 *
2104 * Returns NULL if there are problems with the hints file,
2105 * or if the search path there is empty.
2106 */
2107 static const char *
gethints(bool nostdlib)2108 gethints(bool nostdlib)
2109 {
2110 static char *filtered_path;
2111 static const char *hints;
2112 static struct elfhints_hdr hdr;
2113 struct fill_search_info_args sargs, hargs;
2114 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
2115 struct dl_serpath *SLPpath, *hintpath;
2116 char *p;
2117 struct stat hint_stat;
2118 unsigned int SLPndx, hintndx, fndx, fcount;
2119 int fd;
2120 size_t flen;
2121 uint32_t dl;
2122 uint32_t magic; /* Magic number */
2123 uint32_t version; /* File version (1) */
2124 uint32_t strtab; /* Offset of string table in file */
2125 uint32_t dirlist; /* Offset of directory list in string table */
2126 uint32_t dirlistlen; /* strlen(dirlist) */
2127 bool is_le; /* Does the hints file use little endian */
2128 bool skip;
2129
2130 /* First call, read the hints file */
2131 if (hints == NULL) {
2132 /* Keep from trying again in case the hints file is bad. */
2133 hints = "";
2134
2135 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) ==
2136 -1) {
2137 dbg("failed to open hints file \"%s\"",
2138 ld_elf_hints_path);
2139 return (NULL);
2140 }
2141
2142 /*
2143 * Check of hdr.dirlistlen value against type limit
2144 * intends to pacify static analyzers. Further
2145 * paranoia leads to checks that dirlist is fully
2146 * contained in the file range.
2147 */
2148 if (read(fd, &hdr, sizeof hdr) != sizeof hdr) {
2149 dbg("failed to read %lu bytes from hints file \"%s\"",
2150 (u_long)sizeof hdr, ld_elf_hints_path);
2151 cleanup1:
2152 close(fd);
2153 hdr.dirlistlen = 0;
2154 return (NULL);
2155 }
2156 dbg("host byte-order: %s-endian",
2157 le32toh(1) == 1 ? "little" : "big");
2158 dbg("hints file byte-order: %s-endian",
2159 hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big");
2160 is_le = /*htole32(1) == 1 || */ hdr.magic ==
2161 htole32(ELFHINTS_MAGIC);
2162 magic = COND_SWAP(hdr.magic);
2163 version = COND_SWAP(hdr.version);
2164 strtab = COND_SWAP(hdr.strtab);
2165 dirlist = COND_SWAP(hdr.dirlist);
2166 dirlistlen = COND_SWAP(hdr.dirlistlen);
2167 if (magic != ELFHINTS_MAGIC) {
2168 dbg("invalid magic number %#08x (expected: %#08x)",
2169 magic, ELFHINTS_MAGIC);
2170 goto cleanup1;
2171 }
2172 if (version != 1) {
2173 dbg("hints file version %d (expected: 1)", version);
2174 goto cleanup1;
2175 }
2176 if (dirlistlen > UINT_MAX / 2) {
2177 dbg("directory list is to long: %d > %d", dirlistlen,
2178 UINT_MAX / 2);
2179 goto cleanup1;
2180 }
2181 if (fstat(fd, &hint_stat) == -1) {
2182 dbg("failed to find length of hints file \"%s\"",
2183 ld_elf_hints_path);
2184 goto cleanup1;
2185 }
2186 dl = strtab;
2187 if (dl + dirlist < dl) {
2188 dbg("invalid string table position %d", dl);
2189 goto cleanup1;
2190 }
2191 dl += dirlist;
2192 if (dl + dirlistlen < dl) {
2193 dbg("invalid directory list offset %d", dirlist);
2194 goto cleanup1;
2195 }
2196 dl += dirlistlen;
2197 if (dl > hint_stat.st_size) {
2198 dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)",
2199 ld_elf_hints_path, dl,
2200 (uintmax_t)hint_stat.st_size);
2201 goto cleanup1;
2202 }
2203 p = xmalloc(dirlistlen + 1);
2204 if (pread(fd, p, dirlistlen + 1, strtab + dirlist) !=
2205 (ssize_t)dirlistlen + 1 || p[dirlistlen] != '\0') {
2206 free(p);
2207 dbg(
2208 "failed to read %d bytes starting at %d from hints file \"%s\"",
2209 dirlistlen + 1, strtab + dirlist,
2210 ld_elf_hints_path);
2211 goto cleanup1;
2212 }
2213 hints = p;
2214 close(fd);
2215 }
2216
2217 /*
2218 * If caller agreed to receive list which includes the default
2219 * paths, we are done. Otherwise, if we still did not
2220 * calculated filtered result, do it now.
2221 */
2222 if (!nostdlib)
2223 return (hints[0] != '\0' ? hints : NULL);
2224 if (filtered_path != NULL)
2225 goto filt_ret;
2226
2227 /*
2228 * Obtain the list of all configured search paths, and the
2229 * list of the default paths.
2230 *
2231 * First estimate the size of the results.
2232 */
2233 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2234 smeta.dls_cnt = 0;
2235 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2236 hmeta.dls_cnt = 0;
2237
2238 sargs.request = RTLD_DI_SERINFOSIZE;
2239 sargs.serinfo = &smeta;
2240 hargs.request = RTLD_DI_SERINFOSIZE;
2241 hargs.serinfo = &hmeta;
2242
2243 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2244 &sargs);
2245 path_enumerate(hints, fill_search_info, NULL, &hargs);
2246
2247 SLPinfo = xmalloc(smeta.dls_size);
2248 hintinfo = xmalloc(hmeta.dls_size);
2249
2250 /*
2251 * Next fetch both sets of paths.
2252 */
2253 sargs.request = RTLD_DI_SERINFO;
2254 sargs.serinfo = SLPinfo;
2255 sargs.serpath = &SLPinfo->dls_serpath[0];
2256 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2257
2258 hargs.request = RTLD_DI_SERINFO;
2259 hargs.serinfo = hintinfo;
2260 hargs.serpath = &hintinfo->dls_serpath[0];
2261 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2262
2263 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2264 &sargs);
2265 path_enumerate(hints, fill_search_info, NULL, &hargs);
2266
2267 /*
2268 * Now calculate the difference between two sets, by excluding
2269 * standard paths from the full set.
2270 */
2271 fndx = 0;
2272 fcount = 0;
2273 filtered_path = xmalloc(dirlistlen + 1);
2274 hintpath = &hintinfo->dls_serpath[0];
2275 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2276 skip = false;
2277 SLPpath = &SLPinfo->dls_serpath[0];
2278 /*
2279 * Check each standard path against current.
2280 */
2281 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2282 /* matched, skip the path */
2283 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2284 skip = true;
2285 break;
2286 }
2287 }
2288 if (skip)
2289 continue;
2290 /*
2291 * Not matched against any standard path, add the path
2292 * to result. Separate consequtive paths with ':'.
2293 */
2294 if (fcount > 0) {
2295 filtered_path[fndx] = ':';
2296 fndx++;
2297 }
2298 fcount++;
2299 flen = strlen(hintpath->dls_name);
2300 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2301 fndx += flen;
2302 }
2303 filtered_path[fndx] = '\0';
2304
2305 free(SLPinfo);
2306 free(hintinfo);
2307
2308 filt_ret:
2309 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2310 }
2311
2312 static void
init_dag(Obj_Entry * root)2313 init_dag(Obj_Entry *root)
2314 {
2315 const Needed_Entry *needed;
2316 const Objlist_Entry *elm;
2317 DoneList donelist;
2318
2319 if (root->dag_inited)
2320 return;
2321 donelist_init(&donelist);
2322
2323 /* Root object belongs to own DAG. */
2324 objlist_push_tail(&root->dldags, root);
2325 objlist_push_tail(&root->dagmembers, root);
2326 donelist_check(&donelist, root);
2327
2328 /*
2329 * Add dependencies of root object to DAG in breadth order
2330 * by exploiting the fact that each new object get added
2331 * to the tail of the dagmembers list.
2332 */
2333 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2334 for (needed = elm->obj->needed; needed != NULL;
2335 needed = needed->next) {
2336 if (needed->obj == NULL ||
2337 donelist_check(&donelist, needed->obj))
2338 continue;
2339 objlist_push_tail(&needed->obj->dldags, root);
2340 objlist_push_tail(&root->dagmembers, needed->obj);
2341 }
2342 }
2343 root->dag_inited = true;
2344 }
2345
2346 static void
init_marker(Obj_Entry * marker)2347 init_marker(Obj_Entry *marker)
2348 {
2349 bzero(marker, sizeof(*marker));
2350 marker->marker = true;
2351 }
2352
2353 Obj_Entry *
globallist_curr(const Obj_Entry * obj)2354 globallist_curr(const Obj_Entry *obj)
2355 {
2356 for (;;) {
2357 if (obj == NULL)
2358 return (NULL);
2359 if (!obj->marker)
2360 return (__DECONST(Obj_Entry *, obj));
2361 obj = TAILQ_PREV(obj, obj_entry_q, next);
2362 }
2363 }
2364
2365 Obj_Entry *
globallist_next(const Obj_Entry * obj)2366 globallist_next(const Obj_Entry *obj)
2367 {
2368 for (;;) {
2369 obj = TAILQ_NEXT(obj, next);
2370 if (obj == NULL)
2371 return (NULL);
2372 if (!obj->marker)
2373 return (__DECONST(Obj_Entry *, obj));
2374 }
2375 }
2376
2377 /* Prevent the object from being unmapped while the bind lock is dropped. */
2378 static void
hold_object(Obj_Entry * obj)2379 hold_object(Obj_Entry *obj)
2380 {
2381 obj->holdcount++;
2382 }
2383
2384 static void
unhold_object(Obj_Entry * obj)2385 unhold_object(Obj_Entry *obj)
2386 {
2387 assert(obj->holdcount > 0);
2388 if (--obj->holdcount == 0 && obj->unholdfree)
2389 release_object(obj);
2390 }
2391
2392 static void
process_z(Obj_Entry * root)2393 process_z(Obj_Entry *root)
2394 {
2395 const Objlist_Entry *elm;
2396 Obj_Entry *obj;
2397
2398 /*
2399 * Walk over object DAG and process every dependent object
2400 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2401 * to grow their own DAG.
2402 *
2403 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2404 * symlook_global() to work.
2405 *
2406 * For DF_1_NODELETE, the DAG should have its reference upped.
2407 */
2408 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2409 obj = elm->obj;
2410 if (obj == NULL)
2411 continue;
2412 if (obj->z_nodelete && !obj->ref_nodel) {
2413 dbg("obj %s -z nodelete", obj->path);
2414 init_dag(obj);
2415 ref_dag(obj);
2416 obj->ref_nodel = true;
2417 }
2418 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2419 dbg("obj %s -z global", obj->path);
2420 objlist_push_tail(&list_global, obj);
2421 init_dag(obj);
2422 }
2423 }
2424 }
2425
2426 static void
parse_rtld_phdr(Obj_Entry * obj)2427 parse_rtld_phdr(Obj_Entry *obj)
2428 {
2429 const Elf_Phdr *ph;
2430 Elf_Addr note_start, note_end;
2431 bool first_seg;
2432
2433 first_seg = true;
2434 obj->stack_flags = PF_X | PF_R | PF_W;
2435 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
2436 switch (ph->p_type) {
2437 case PT_LOAD:
2438 if (first_seg) {
2439 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr);
2440 first_seg = false;
2441 }
2442 obj->mapsize = rtld_round_page(ph->p_vaddr +
2443 ph->p_memsz) - obj->vaddrbase;
2444 break;
2445 case PT_GNU_STACK:
2446 obj->stack_flags = ph->p_flags;
2447 break;
2448 case PT_NOTE:
2449 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2450 note_end = note_start + ph->p_filesz;
2451 digest_notes(obj, note_start, note_end);
2452 break;
2453 }
2454 }
2455 }
2456
2457 /*
2458 * Initialize the dynamic linker. The argument is the address at which
2459 * the dynamic linker has been mapped into memory. The primary task of
2460 * this function is to relocate the dynamic linker.
2461 */
2462 static void
init_rtld(caddr_t mapbase,Elf_Auxinfo ** aux_info)2463 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2464 {
2465 Obj_Entry objtmp; /* Temporary rtld object */
2466 const Elf_Ehdr *ehdr;
2467 const Elf_Dyn *dyn_rpath;
2468 const Elf_Dyn *dyn_soname;
2469 const Elf_Dyn *dyn_runpath;
2470
2471 /*
2472 * Conjure up an Obj_Entry structure for the dynamic linker.
2473 *
2474 * The "path" member can't be initialized yet because string constants
2475 * cannot yet be accessed. Below we will set it correctly.
2476 */
2477 memset(&objtmp, 0, sizeof(objtmp));
2478 objtmp.path = NULL;
2479 objtmp.rtld = true;
2480 objtmp.mapbase = mapbase;
2481 #ifdef PIC
2482 objtmp.relocbase = mapbase;
2483 #endif
2484
2485 objtmp.dynamic = rtld_dynamic(&objtmp);
2486 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2487 assert(objtmp.needed == NULL);
2488 assert(!objtmp.textrel);
2489 /*
2490 * Temporarily put the dynamic linker entry into the object list, so
2491 * that symbols can be found.
2492 */
2493 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2494
2495 ehdr = (Elf_Ehdr *)mapbase;
2496 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2497 objtmp.phnum = ehdr->e_phnum;
2498
2499 /* Initialize the object list. */
2500 TAILQ_INIT(&obj_list);
2501
2502 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2503 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2504
2505 /* The page size is required by the dynamic memory allocator. */
2506 init_pagesizes(aux_info);
2507
2508 if (aux_info[AT_OSRELDATE] != NULL)
2509 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2510
2511 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2512
2513 /* Replace the path with a dynamically allocated copy. */
2514 obj_rtld.path = xstrdup(ld_path_rtld);
2515
2516 parse_rtld_phdr(&obj_rtld);
2517 if (obj_enforce_relro(&obj_rtld) == -1)
2518 rtld_die();
2519
2520 r_debug.r_version = R_DEBUG_VERSION;
2521 r_debug.r_brk = r_debug_state;
2522 r_debug.r_state = RT_CONSISTENT;
2523 r_debug.r_ldbase = obj_rtld.relocbase;
2524 }
2525
2526 /*
2527 * Retrieve the array of supported page sizes. The kernel provides the page
2528 * sizes in increasing order.
2529 */
2530 static void
init_pagesizes(Elf_Auxinfo ** aux_info)2531 init_pagesizes(Elf_Auxinfo **aux_info)
2532 {
2533 static size_t psa[MAXPAGESIZES];
2534 int mib[2];
2535 size_t len, size;
2536
2537 if (aux_info[AT_PAGESIZES] != NULL &&
2538 aux_info[AT_PAGESIZESLEN] != NULL) {
2539 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2540 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2541 } else {
2542 len = 2;
2543 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2544 size = sizeof(psa);
2545 else {
2546 /* As a fallback, retrieve the base page size. */
2547 size = sizeof(psa[0]);
2548 if (aux_info[AT_PAGESZ] != NULL) {
2549 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2550 goto psa_filled;
2551 } else {
2552 mib[0] = CTL_HW;
2553 mib[1] = HW_PAGESIZE;
2554 len = 2;
2555 }
2556 }
2557 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2558 _rtld_error("sysctl for hw.pagesize(s) failed");
2559 rtld_die();
2560 }
2561 psa_filled:
2562 pagesizes = psa;
2563 }
2564 npagesizes = size / sizeof(pagesizes[0]);
2565 /* Discard any invalid entries at the end of the array. */
2566 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2567 npagesizes--;
2568
2569 page_size = pagesizes[0];
2570 }
2571
2572 /*
2573 * Add the init functions from a needed object list (and its recursive
2574 * needed objects) to "list". This is not used directly; it is a helper
2575 * function for initlist_add_objects(). The write lock must be held
2576 * when this function is called.
2577 */
2578 static void
initlist_add_neededs(Needed_Entry * needed,Objlist * list,Objlist * iflist)2579 initlist_add_neededs(Needed_Entry *needed, Objlist *list, Objlist *iflist)
2580 {
2581 /* Recursively process the successor needed objects. */
2582 if (needed->next != NULL)
2583 initlist_add_neededs(needed->next, list, iflist);
2584
2585 /* Process the current needed object. */
2586 if (needed->obj != NULL)
2587 initlist_add_objects(needed->obj, needed->obj, list, iflist);
2588 }
2589
2590 /*
2591 * Scan all of the DAGs rooted in the range of objects from "obj" to
2592 * "tail" and add their init functions to "list". This recurses over
2593 * the DAGs and ensure the proper init ordering such that each object's
2594 * needed libraries are initialized before the object itself. At the
2595 * same time, this function adds the objects to the global finalization
2596 * list "list_fini" in the opposite order. The write lock must be
2597 * held when this function is called.
2598 */
2599 static void
initlist_for_loaded_obj(Obj_Entry * obj,Obj_Entry * tail,Objlist * list)2600 initlist_for_loaded_obj(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2601 {
2602 Objlist iflist; /* initfirst objs and their needed */
2603 Objlist_Entry *tmp;
2604
2605 objlist_init(&iflist);
2606 initlist_add_objects(obj, tail, list, &iflist);
2607
2608 STAILQ_FOREACH(tmp, &iflist, link) {
2609 Obj_Entry *tobj = tmp->obj;
2610
2611 if ((tobj->fini != 0 || tobj->fini_array != NULL) &&
2612 !tobj->on_fini_list) {
2613 objlist_push_tail(&list_fini, tobj);
2614 tobj->on_fini_list = true;
2615 }
2616 }
2617
2618 /*
2619 * This might result in the same object appearing more
2620 * than once on the init list. objlist_call_init()
2621 * uses obj->init_scanned to avoid dup calls.
2622 */
2623 STAILQ_REVERSE(&iflist, Struct_Objlist_Entry, link);
2624 STAILQ_FOREACH(tmp, &iflist, link)
2625 objlist_push_head(list, tmp->obj);
2626
2627 objlist_clear(&iflist);
2628 }
2629
2630 static void
initlist_add_objects(Obj_Entry * obj,Obj_Entry * tail,Objlist * list,Objlist * iflist)2631 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list,
2632 Objlist *iflist)
2633 {
2634 Obj_Entry *nobj;
2635
2636 if (obj->init_done)
2637 return;
2638
2639 if (obj->z_initfirst || list == NULL) {
2640 /*
2641 * Ignore obj->init_scanned. The object might indeed
2642 * already be on the init list, but due to being
2643 * needed by an initfirst object, we must put it at
2644 * the head of the init list. obj->init_done protects
2645 * against double-initialization.
2646 */
2647 if (obj->needed != NULL)
2648 initlist_add_neededs(obj->needed, NULL, iflist);
2649 if (obj->needed_filtees != NULL)
2650 initlist_add_neededs(obj->needed_filtees, NULL,
2651 iflist);
2652 if (obj->needed_aux_filtees != NULL)
2653 initlist_add_neededs(obj->needed_aux_filtees,
2654 NULL, iflist);
2655 objlist_push_tail(iflist, obj);
2656 } else {
2657 if (obj->init_scanned)
2658 return;
2659 obj->init_scanned = true;
2660
2661 /* Recursively process the successor objects. */
2662 nobj = globallist_next(obj);
2663 if (nobj != NULL && obj != tail)
2664 initlist_add_objects(nobj, tail, list, iflist);
2665
2666 /* Recursively process the needed objects. */
2667 if (obj->needed != NULL)
2668 initlist_add_neededs(obj->needed, list, iflist);
2669 if (obj->needed_filtees != NULL)
2670 initlist_add_neededs(obj->needed_filtees, list,
2671 iflist);
2672 if (obj->needed_aux_filtees != NULL)
2673 initlist_add_neededs(obj->needed_aux_filtees, list,
2674 iflist);
2675
2676 /* Add the object to the init list. */
2677 objlist_push_tail(list, obj);
2678
2679 /*
2680 * Add the object to the global fini list in the
2681 * reverse order.
2682 */
2683 if ((obj->fini != 0 || obj->fini_array != NULL) &&
2684 !obj->on_fini_list) {
2685 objlist_push_head(&list_fini, obj);
2686 obj->on_fini_list = true;
2687 }
2688 }
2689 }
2690
2691 static void
free_needed_filtees(Needed_Entry * n,RtldLockState * lockstate)2692 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2693 {
2694 Needed_Entry *needed, *needed1;
2695
2696 for (needed = n; needed != NULL; needed = needed->next) {
2697 if (needed->obj != NULL) {
2698 dlclose_locked(needed->obj, lockstate);
2699 needed->obj = NULL;
2700 }
2701 }
2702 for (needed = n; needed != NULL; needed = needed1) {
2703 needed1 = needed->next;
2704 free(needed);
2705 }
2706 }
2707
2708 static void
unload_filtees(Obj_Entry * obj,RtldLockState * lockstate)2709 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2710 {
2711 free_needed_filtees(obj->needed_filtees, lockstate);
2712 obj->needed_filtees = NULL;
2713 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2714 obj->needed_aux_filtees = NULL;
2715 obj->filtees_loaded = false;
2716 }
2717
2718 static void
load_filtee1(Obj_Entry * obj,Needed_Entry * needed,int flags,RtldLockState * lockstate)2719 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2720 RtldLockState *lockstate)
2721 {
2722 for (; needed != NULL; needed = needed->next) {
2723 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2724 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW :
2725 RTLD_LAZY) | RTLD_LOCAL, lockstate);
2726 }
2727 }
2728
2729 static void
load_filtees(Obj_Entry * obj,int flags,RtldLockState * lockstate)2730 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2731 {
2732 if (obj->filtees_loaded || obj->filtees_loading)
2733 return;
2734 lock_restart_for_upgrade(lockstate);
2735 obj->filtees_loading = true;
2736 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2737 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2738 obj->filtees_loaded = true;
2739 obj->filtees_loading = false;
2740 }
2741
2742 static int
process_needed(Obj_Entry * obj,Needed_Entry * needed,int flags)2743 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2744 {
2745 Obj_Entry *obj1;
2746
2747 for (; needed != NULL; needed = needed->next) {
2748 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1,
2749 obj, flags & ~RTLD_LO_NOLOAD);
2750 if (obj1 == NULL && !ld_tracing &&
2751 (flags & RTLD_LO_FILTEES) == 0)
2752 return (-1);
2753 }
2754 return (0);
2755 }
2756
2757 /*
2758 * Given a shared object, traverse its list of needed objects, and load
2759 * each of them. Returns 0 on success. Generates an error message and
2760 * returns -1 on failure.
2761 */
2762 static int
load_needed_objects(Obj_Entry * first,int flags)2763 load_needed_objects(Obj_Entry *first, int flags)
2764 {
2765 Obj_Entry *obj;
2766
2767 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2768 if (obj->marker)
2769 continue;
2770 if (process_needed(obj, obj->needed, flags) == -1)
2771 return (-1);
2772 }
2773 return (0);
2774 }
2775
2776 static int
load_preload_objects(const char * penv,bool isfd)2777 load_preload_objects(const char *penv, bool isfd)
2778 {
2779 Obj_Entry *obj;
2780 const char *name;
2781 size_t len;
2782 char savech, *p, *psave;
2783 int fd;
2784 static const char delim[] = " \t:;";
2785
2786 if (penv == NULL)
2787 return (0);
2788
2789 p = psave = xstrdup(penv);
2790 p += strspn(p, delim);
2791 while (*p != '\0') {
2792 len = strcspn(p, delim);
2793
2794 savech = p[len];
2795 p[len] = '\0';
2796 if (isfd) {
2797 name = NULL;
2798 fd = parse_integer(p);
2799 if (fd == -1) {
2800 free(psave);
2801 return (-1);
2802 }
2803 } else {
2804 name = p;
2805 fd = -1;
2806 }
2807
2808 obj = load_object(name, fd, NULL, 0);
2809 if (obj == NULL) {
2810 free(psave);
2811 return (-1); /* XXX - cleanup */
2812 }
2813 obj->z_interpose = true;
2814 p[len] = savech;
2815 p += len;
2816 p += strspn(p, delim);
2817 }
2818 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2819
2820 free(psave);
2821 return (0);
2822 }
2823
2824 static const char *
printable_path(const char * path)2825 printable_path(const char *path)
2826 {
2827 return (path == NULL ? "<unknown>" : path);
2828 }
2829
2830 /*
2831 * Load a shared object into memory, if it is not already loaded. The
2832 * object may be specified by name or by user-supplied file descriptor
2833 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2834 * duplicate is.
2835 *
2836 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2837 * on failure.
2838 */
2839 static Obj_Entry *
load_object(const char * name,int fd_u,const Obj_Entry * refobj,int flags)2840 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2841 {
2842 Obj_Entry *obj;
2843 int fd;
2844 struct stat sb;
2845 char *path;
2846
2847 fd = -1;
2848 if (name != NULL) {
2849 TAILQ_FOREACH(obj, &obj_list, next) {
2850 if (obj->marker || obj->doomed)
2851 continue;
2852 if (object_match_name(obj, name))
2853 return (obj);
2854 }
2855
2856 path = find_library(name, refobj, &fd);
2857 if (path == NULL)
2858 return (NULL);
2859 } else
2860 path = NULL;
2861
2862 if (fd >= 0) {
2863 /*
2864 * search_library_pathfds() opens a fresh file descriptor for
2865 * the library, so there is no need to dup().
2866 */
2867 } else if (fd_u == -1) {
2868 /*
2869 * If we didn't find a match by pathname, or the name is not
2870 * supplied, open the file and check again by device and inode.
2871 * This avoids false mismatches caused by multiple links or ".."
2872 * in pathnames.
2873 *
2874 * To avoid a race, we open the file and use fstat() rather than
2875 * using stat().
2876 */
2877 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2878 _rtld_error("Cannot open \"%s\"", path);
2879 free(path);
2880 return (NULL);
2881 }
2882 } else {
2883 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2884 if (fd == -1) {
2885 _rtld_error("Cannot dup fd");
2886 free(path);
2887 return (NULL);
2888 }
2889 }
2890 if (fstat(fd, &sb) == -1) {
2891 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2892 close(fd);
2893 free(path);
2894 return (NULL);
2895 }
2896 TAILQ_FOREACH(obj, &obj_list, next) {
2897 if (obj->marker || obj->doomed)
2898 continue;
2899 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2900 break;
2901 }
2902 if (obj != NULL) {
2903 if (name != NULL)
2904 object_add_name(obj, name);
2905 free(path);
2906 close(fd);
2907 return (obj);
2908 }
2909 if (flags & RTLD_LO_NOLOAD) {
2910 free(path);
2911 close(fd);
2912 return (NULL);
2913 }
2914
2915 /* First use of this object, so we must map it in */
2916 obj = do_load_object(fd, name, path, &sb, flags);
2917 if (obj == NULL)
2918 free(path);
2919 close(fd);
2920
2921 return (obj);
2922 }
2923
2924 static Obj_Entry *
do_load_object(int fd,const char * name,char * path,struct stat * sbp,int flags)2925 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2926 int flags)
2927 {
2928 Obj_Entry *obj;
2929 struct statfs fs;
2930
2931 /*
2932 * First, make sure that environment variables haven't been
2933 * used to circumvent the noexec flag on a filesystem.
2934 * We ignore fstatfs(2) failures, since fd might reference
2935 * not a file, e.g. shmfd.
2936 */
2937 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 &&
2938 (fs.f_flags & MNT_NOEXEC) != 0) {
2939 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2940 return (NULL);
2941 }
2942
2943 dbg("loading \"%s\"", printable_path(path));
2944 obj = map_object(fd, printable_path(path), sbp, false);
2945 if (obj == NULL)
2946 return (NULL);
2947
2948 /*
2949 * If DT_SONAME is present in the object, digest_dynamic2 already
2950 * added it to the object names.
2951 */
2952 if (name != NULL)
2953 object_add_name(obj, name);
2954 obj->path = path;
2955 if (!digest_dynamic(obj, 0))
2956 goto errp;
2957 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2958 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2959 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
2960 dbg("refusing to load PIE executable \"%s\"", obj->path);
2961 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2962 goto errp;
2963 }
2964 if (obj->z_noopen &&
2965 (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == RTLD_LO_DLOPEN) {
2966 dbg("refusing to load non-loadable \"%s\"", obj->path);
2967 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2968 goto errp;
2969 }
2970
2971 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2972 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2973 obj_count++;
2974 obj_loads++;
2975 linkmap_add(obj); /* for GDB & dlinfo() */
2976 max_stack_flags |= obj->stack_flags;
2977
2978 dbg(" %p .. %p: %s", obj->mapbase, obj->mapbase + obj->mapsize - 1,
2979 obj->path);
2980 if (obj->textrel)
2981 dbg(" WARNING: %s has impure text", obj->path);
2982 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2983 obj->path);
2984
2985 return (obj);
2986
2987 errp:
2988 munmap(obj->mapbase, obj->mapsize);
2989 obj_free(obj);
2990 return (NULL);
2991 }
2992
2993 static int
load_kpreload(const void * addr)2994 load_kpreload(const void *addr)
2995 {
2996 Obj_Entry *obj;
2997 const Elf_Ehdr *ehdr;
2998 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn;
2999 static const char kname[] = "[vdso]";
3000
3001 ehdr = addr;
3002 if (!check_elf_headers(ehdr, "kpreload"))
3003 return (-1);
3004 obj = obj_new();
3005 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff);
3006 obj->phdr = phdr;
3007 obj->phnum = ehdr->e_phnum;
3008 phlimit = phdr + ehdr->e_phnum;
3009 seg0 = segn = NULL;
3010
3011 for (; phdr < phlimit; phdr++) {
3012 switch (phdr->p_type) {
3013 case PT_DYNAMIC:
3014 phdyn = phdr;
3015 break;
3016 case PT_GNU_STACK:
3017 /* Absense of PT_GNU_STACK implies stack_flags == 0. */
3018 obj->stack_flags = phdr->p_flags;
3019 break;
3020 case PT_LOAD:
3021 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr)
3022 seg0 = phdr;
3023 if (segn == NULL ||
3024 segn->p_vaddr + segn->p_memsz <
3025 phdr->p_vaddr + phdr->p_memsz)
3026 segn = phdr;
3027 break;
3028 }
3029 }
3030
3031 obj->mapbase = __DECONST(caddr_t, addr);
3032 obj->mapsize = segn->p_vaddr + segn->p_memsz;
3033 obj->vaddrbase = 0;
3034 obj->relocbase = obj->mapbase;
3035
3036 object_add_name(obj, kname);
3037 obj->path = xstrdup(kname);
3038 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr);
3039
3040 if (!digest_dynamic(obj, 0)) {
3041 obj_free(obj);
3042 return (-1);
3043 }
3044
3045 /*
3046 * We assume that kernel-preloaded object does not need
3047 * relocation. It is currently written into read-only page,
3048 * handling relocations would mean we need to allocate at
3049 * least one additional page per AS.
3050 */
3051 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p",
3052 obj->path, obj->mapbase, obj->phdr, seg0,
3053 obj->relocbase + seg0->p_vaddr, obj->dynamic);
3054
3055 TAILQ_INSERT_TAIL(&obj_list, obj, next);
3056 obj_count++;
3057 obj_loads++;
3058 linkmap_add(obj); /* for GDB & dlinfo() */
3059 max_stack_flags |= obj->stack_flags;
3060
3061 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3062 obj->path);
3063 return (0);
3064 }
3065
3066 Obj_Entry *
obj_from_addr(const void * addr)3067 obj_from_addr(const void *addr)
3068 {
3069 Obj_Entry *obj;
3070
3071 TAILQ_FOREACH(obj, &obj_list, next) {
3072 if (obj->marker)
3073 continue;
3074 if (addr < (void *)obj->mapbase)
3075 continue;
3076 if (addr < (void *)(obj->mapbase + obj->mapsize))
3077 return obj;
3078 }
3079 return (NULL);
3080 }
3081
3082 static void
preinit_main(void)3083 preinit_main(void)
3084 {
3085 uintptr_t *preinit_addr;
3086 int index;
3087
3088 preinit_addr = obj_main->preinit_array;
3089 if (preinit_addr == NULL)
3090 return;
3091
3092 for (index = 0; index < obj_main->preinit_array_num; index++) {
3093 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
3094 dbg("calling preinit function for %s at %p",
3095 obj_main->path, (void *)preinit_addr[index]);
3096 LD_UTRACE(UTRACE_INIT_CALL, obj_main,
3097 (void *)preinit_addr[index], 0, 0, obj_main->path);
3098 call_init_pointer(obj_main, preinit_addr[index]);
3099 }
3100 }
3101 }
3102
3103 /*
3104 * Call the finalization functions for each of the objects in "list"
3105 * belonging to the DAG of "root" and referenced once. If NULL "root"
3106 * is specified, every finalization function will be called regardless
3107 * of the reference count and the list elements won't be freed. All of
3108 * the objects are expected to have non-NULL fini functions.
3109 */
3110 static void
objlist_call_fini(Objlist * list,Obj_Entry * root,RtldLockState * lockstate)3111 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
3112 {
3113 Objlist_Entry *elm;
3114 struct dlerror_save *saved_msg;
3115 uintptr_t *fini_addr;
3116 int index;
3117
3118 assert(root == NULL || root->refcount == 1);
3119
3120 if (root != NULL)
3121 root->doomed = true;
3122
3123 /*
3124 * Preserve the current error message since a fini function might
3125 * call into the dynamic linker and overwrite it.
3126 */
3127 saved_msg = errmsg_save();
3128 do {
3129 STAILQ_FOREACH(elm, list, link) {
3130 if (root != NULL &&
3131 (elm->obj->refcount != 1 ||
3132 objlist_find(&root->dagmembers, elm->obj) ==
3133 NULL))
3134 continue;
3135 /* Remove object from fini list to prevent recursive
3136 * invocation. */
3137 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3138 /* Ensure that new references cannot be acquired. */
3139 elm->obj->doomed = true;
3140
3141 hold_object(elm->obj);
3142 lock_release(rtld_bind_lock, lockstate);
3143 /*
3144 * It is legal to have both DT_FINI and DT_FINI_ARRAY
3145 * defined. When this happens, DT_FINI_ARRAY is
3146 * processed first.
3147 */
3148 fini_addr = elm->obj->fini_array;
3149 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
3150 for (index = elm->obj->fini_array_num - 1;
3151 index >= 0; index--) {
3152 if (fini_addr[index] != 0 &&
3153 fini_addr[index] != 1) {
3154 dbg("calling fini function for %s at %p",
3155 elm->obj->path,
3156 (void *)fini_addr[index]);
3157 LD_UTRACE(UTRACE_FINI_CALL,
3158 elm->obj,
3159 (void *)fini_addr[index], 0,
3160 0, elm->obj->path);
3161 call_initfini_pointer(elm->obj,
3162 fini_addr[index]);
3163 }
3164 }
3165 }
3166 if (elm->obj->fini != 0) {
3167 dbg("calling fini function for %s at %p",
3168 elm->obj->path, (void *)elm->obj->fini);
3169 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
3170 (void *)elm->obj->fini, 0, 0,
3171 elm->obj->path);
3172 call_initfini_pointer(elm->obj, elm->obj->fini);
3173 }
3174 wlock_acquire(rtld_bind_lock, lockstate);
3175 unhold_object(elm->obj);
3176 /* No need to free anything if process is going down. */
3177 if (root != NULL)
3178 free(elm);
3179 /*
3180 * We must restart the list traversal after every fini
3181 * call because a dlclose() call from the fini function
3182 * or from another thread might have modified the
3183 * reference counts.
3184 */
3185 break;
3186 }
3187 } while (elm != NULL);
3188 errmsg_restore(saved_msg);
3189 }
3190
3191 /*
3192 * Call the initialization functions for each of the objects in
3193 * "list". All of the objects are expected to have non-NULL init
3194 * functions.
3195 */
3196 static void
objlist_call_init(Objlist * list,RtldLockState * lockstate)3197 objlist_call_init(Objlist *list, RtldLockState *lockstate)
3198 {
3199 Objlist_Entry *elm;
3200 Obj_Entry *obj;
3201 struct dlerror_save *saved_msg;
3202 uintptr_t *init_addr;
3203 void (*reg)(void (*)(void));
3204 int index;
3205
3206 /*
3207 * Clean init_scanned flag so that objects can be rechecked and
3208 * possibly initialized earlier if any of vectors called below
3209 * cause the change by using dlopen.
3210 */
3211 TAILQ_FOREACH(obj, &obj_list, next) {
3212 if (obj->marker)
3213 continue;
3214 obj->init_scanned = false;
3215 }
3216
3217 /*
3218 * Preserve the current error message since an init function might
3219 * call into the dynamic linker and overwrite it.
3220 */
3221 saved_msg = errmsg_save();
3222 STAILQ_FOREACH(elm, list, link) {
3223 if (elm->obj->init_done) /* Initialized early. */
3224 continue;
3225 /*
3226 * Race: other thread might try to use this object before
3227 * current one completes the initialization. Not much can be
3228 * done here without better locking.
3229 */
3230 elm->obj->init_done = true;
3231 hold_object(elm->obj);
3232 reg = NULL;
3233 if (elm->obj == obj_main && obj_main->crt_no_init) {
3234 reg = (void (*)(void (*)(void)))
3235 get_program_var_addr("__libc_atexit", lockstate);
3236 }
3237 lock_release(rtld_bind_lock, lockstate);
3238 if (reg != NULL) {
3239 reg(rtld_exit);
3240 rtld_exit_ptr = rtld_nop_exit;
3241 }
3242
3243 /*
3244 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
3245 * When this happens, DT_INIT is processed first.
3246 */
3247 if (elm->obj->init != 0) {
3248 dbg("calling init function for %s at %p",
3249 elm->obj->path, (void *)elm->obj->init);
3250 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3251 (void *)elm->obj->init, 0, 0, elm->obj->path);
3252 call_init_pointer(elm->obj, elm->obj->init);
3253 }
3254 init_addr = elm->obj->init_array;
3255 if (init_addr != NULL) {
3256 for (index = 0; index < elm->obj->init_array_num;
3257 index++) {
3258 if (init_addr[index] != 0 &&
3259 init_addr[index] != 1) {
3260 dbg("calling init function for %s at %p",
3261 elm->obj->path,
3262 (void *)init_addr[index]);
3263 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3264 (void *)init_addr[index], 0, 0,
3265 elm->obj->path);
3266 call_init_pointer(elm->obj,
3267 init_addr[index]);
3268 }
3269 }
3270 }
3271 wlock_acquire(rtld_bind_lock, lockstate);
3272 unhold_object(elm->obj);
3273 }
3274 errmsg_restore(saved_msg);
3275 }
3276
3277 static void
objlist_clear(Objlist * list)3278 objlist_clear(Objlist *list)
3279 {
3280 Objlist_Entry *elm;
3281
3282 while (!STAILQ_EMPTY(list)) {
3283 elm = STAILQ_FIRST(list);
3284 STAILQ_REMOVE_HEAD(list, link);
3285 free(elm);
3286 }
3287 }
3288
3289 static Objlist_Entry *
objlist_find(Objlist * list,const Obj_Entry * obj)3290 objlist_find(Objlist *list, const Obj_Entry *obj)
3291 {
3292 Objlist_Entry *elm;
3293
3294 STAILQ_FOREACH(elm, list, link)
3295 if (elm->obj == obj)
3296 return elm;
3297 return (NULL);
3298 }
3299
3300 static void
objlist_init(Objlist * list)3301 objlist_init(Objlist *list)
3302 {
3303 STAILQ_INIT(list);
3304 }
3305
3306 static void
objlist_push_head(Objlist * list,Obj_Entry * obj)3307 objlist_push_head(Objlist *list, Obj_Entry *obj)
3308 {
3309 Objlist_Entry *elm;
3310
3311 elm = NEW(Objlist_Entry);
3312 elm->obj = obj;
3313 STAILQ_INSERT_HEAD(list, elm, link);
3314 }
3315
3316 static void
objlist_push_tail(Objlist * list,Obj_Entry * obj)3317 objlist_push_tail(Objlist *list, Obj_Entry *obj)
3318 {
3319 Objlist_Entry *elm;
3320
3321 elm = NEW(Objlist_Entry);
3322 elm->obj = obj;
3323 STAILQ_INSERT_TAIL(list, elm, link);
3324 }
3325
3326 static void
objlist_put_after(Objlist * list,Obj_Entry * listobj,Obj_Entry * obj)3327 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
3328 {
3329 Objlist_Entry *elm, *listelm;
3330
3331 STAILQ_FOREACH(listelm, list, link) {
3332 if (listelm->obj == listobj)
3333 break;
3334 }
3335 elm = NEW(Objlist_Entry);
3336 elm->obj = obj;
3337 if (listelm != NULL)
3338 STAILQ_INSERT_AFTER(list, listelm, elm, link);
3339 else
3340 STAILQ_INSERT_TAIL(list, elm, link);
3341 }
3342
3343 static void
objlist_remove(Objlist * list,Obj_Entry * obj)3344 objlist_remove(Objlist *list, Obj_Entry *obj)
3345 {
3346 Objlist_Entry *elm;
3347
3348 if ((elm = objlist_find(list, obj)) != NULL) {
3349 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3350 free(elm);
3351 }
3352 }
3353
3354 /*
3355 * Relocate dag rooted in the specified object.
3356 * Returns 0 on success, or -1 on failure.
3357 */
3358
3359 static int
relocate_object_dag(Obj_Entry * root,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3360 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
3361 int flags, RtldLockState *lockstate)
3362 {
3363 Objlist_Entry *elm;
3364 int error;
3365
3366 error = 0;
3367 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3368 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
3369 lockstate);
3370 if (error == -1)
3371 break;
3372 }
3373 return (error);
3374 }
3375
3376 /*
3377 * Prepare for, or clean after, relocating an object marked with
3378 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
3379 * segments are remapped read-write. After relocations are done, the
3380 * segment's permissions are returned back to the modes specified in
3381 * the phdrs. If any relocation happened, or always for wired
3382 * program, COW is triggered.
3383 */
3384 static int
reloc_textrel_prot(Obj_Entry * obj,bool before)3385 reloc_textrel_prot(Obj_Entry *obj, bool before)
3386 {
3387 const Elf_Phdr *ph;
3388 void *base;
3389 size_t sz;
3390 int prot;
3391
3392 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
3393 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
3394 continue;
3395 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
3396 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) -
3397 rtld_trunc_page(ph->p_vaddr);
3398 prot = before ? (PROT_READ | PROT_WRITE) :
3399 convert_prot(ph->p_flags);
3400 if (mprotect(base, sz, prot) == -1) {
3401 _rtld_error("%s: Cannot write-%sable text segment: %s",
3402 obj->path, before ? "en" : "dis",
3403 rtld_strerror(errno));
3404 return (-1);
3405 }
3406 }
3407 return (0);
3408 }
3409
3410 /* Process RELR relative relocations. */
3411 static void
reloc_relr(Obj_Entry * obj)3412 reloc_relr(Obj_Entry *obj)
3413 {
3414 const Elf_Relr *relr, *relrlim;
3415 Elf_Addr *where;
3416
3417 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize);
3418 for (relr = obj->relr; relr < relrlim; relr++) {
3419 Elf_Relr entry = *relr;
3420
3421 if ((entry & 1) == 0) {
3422 where = (Elf_Addr *)(obj->relocbase + entry);
3423 *where++ += (Elf_Addr)obj->relocbase;
3424 } else {
3425 for (long i = 0; (entry >>= 1) != 0; i++)
3426 if ((entry & 1) != 0)
3427 where[i] += (Elf_Addr)obj->relocbase;
3428 where += CHAR_BIT * sizeof(Elf_Relr) - 1;
3429 }
3430 }
3431 }
3432
3433 /*
3434 * Relocate single object.
3435 * Returns 0 on success, or -1 on failure.
3436 */
3437 static int
relocate_object(Obj_Entry * obj,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3438 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, int flags,
3439 RtldLockState *lockstate)
3440 {
3441 if (obj->relocated)
3442 return (0);
3443 obj->relocated = true;
3444 if (obj != rtldobj)
3445 dbg("relocating \"%s\"", obj->path);
3446
3447 if (obj->symtab == NULL || obj->strtab == NULL ||
3448 !(obj->valid_hash_sysv || obj->valid_hash_gnu))
3449 dbg("object %s has no run-time symbol table", obj->path);
3450
3451 /* There are relocations to the write-protected text segment. */
3452 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3453 return (-1);
3454
3455 /* Process the non-PLT non-IFUNC relocations. */
3456 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3457 return (-1);
3458 reloc_relr(obj);
3459
3460 /* Re-protected the text segment. */
3461 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3462 return (-1);
3463
3464 /* Set the special PLT or GOT entries. */
3465 init_pltgot(obj);
3466
3467 /* Process the PLT relocations. */
3468 if (reloc_plt(obj, flags, lockstate) == -1)
3469 return (-1);
3470 /* Relocate the jump slots if we are doing immediate binding. */
3471 if ((obj->bind_now || bind_now) &&
3472 reloc_jmpslots(obj, flags, lockstate) == -1)
3473 return (-1);
3474
3475 if (obj != rtldobj && !obj->mainprog && obj_enforce_relro(obj) == -1)
3476 return (-1);
3477
3478 /*
3479 * Set up the magic number and version in the Obj_Entry. These
3480 * were checked in the crt1.o from the original ElfKit, so we
3481 * set them for backward compatibility.
3482 */
3483 obj->magic = RTLD_MAGIC;
3484 obj->version = RTLD_VERSION;
3485
3486 return (0);
3487 }
3488
3489 /*
3490 * Relocate newly-loaded shared objects. The argument is a pointer to
3491 * the Obj_Entry for the first such object. All objects from the first
3492 * to the end of the list of objects are relocated. Returns 0 on success,
3493 * or -1 on failure.
3494 */
3495 static int
relocate_objects(Obj_Entry * first,bool bind_now,Obj_Entry * rtldobj,int flags,RtldLockState * lockstate)3496 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, int flags,
3497 RtldLockState *lockstate)
3498 {
3499 Obj_Entry *obj;
3500 int error;
3501
3502 for (error = 0, obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3503 if (obj->marker)
3504 continue;
3505 error = relocate_object(obj, bind_now, rtldobj, flags,
3506 lockstate);
3507 if (error == -1)
3508 break;
3509 }
3510 return (error);
3511 }
3512
3513 /*
3514 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3515 * referencing STT_GNU_IFUNC symbols is postponed till the other
3516 * relocations are done. The indirect functions specified as
3517 * ifunc are allowed to call other symbols, so we need to have
3518 * objects relocated before asking for resolution from indirects.
3519 *
3520 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3521 * instead of the usual lazy handling of PLT slots. It is
3522 * consistent with how GNU does it.
3523 */
3524 static int
resolve_object_ifunc(Obj_Entry * obj,bool bind_now,int flags,RtldLockState * lockstate)3525 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3526 RtldLockState *lockstate)
3527 {
3528 if (obj->ifuncs_resolved)
3529 return (0);
3530 obj->ifuncs_resolved = true;
3531 if (!obj->irelative && !obj->irelative_nonplt &&
3532 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3533 !obj->non_plt_gnu_ifunc)
3534 return (0);
3535 if (obj_disable_relro(obj) == -1 ||
3536 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3537 (obj->irelative_nonplt &&
3538 reloc_iresolve_nonplt(obj, lockstate) == -1) ||
3539 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3540 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3541 (obj->non_plt_gnu_ifunc &&
3542 reloc_non_plt(obj, &obj_rtld, flags | SYMLOOK_IFUNC,
3543 lockstate) == -1) ||
3544 obj_enforce_relro(obj) == -1)
3545 return (-1);
3546 return (0);
3547 }
3548
3549 static int
initlist_objects_ifunc(Objlist * list,bool bind_now,int flags,RtldLockState * lockstate)3550 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3551 RtldLockState *lockstate)
3552 {
3553 Objlist_Entry *elm;
3554 Obj_Entry *obj;
3555
3556 STAILQ_FOREACH(elm, list, link) {
3557 obj = elm->obj;
3558 if (obj->marker)
3559 continue;
3560 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
3561 return (-1);
3562 }
3563 return (0);
3564 }
3565
3566 /*
3567 * Cleanup procedure. It will be called (by the atexit mechanism) just
3568 * before the process exits.
3569 */
3570 static void
rtld_exit(void)3571 rtld_exit(void)
3572 {
3573 RtldLockState lockstate;
3574
3575 wlock_acquire(rtld_bind_lock, &lockstate);
3576 dbg("rtld_exit()");
3577 objlist_call_fini(&list_fini, NULL, &lockstate);
3578 /* No need to remove the items from the list, since we are exiting. */
3579 if (!libmap_disable)
3580 lm_fini();
3581 lock_release(rtld_bind_lock, &lockstate);
3582 }
3583
3584 static void
rtld_nop_exit(void)3585 rtld_nop_exit(void)
3586 {
3587 }
3588
3589 /*
3590 * Iterate over a search path, translate each element, and invoke the
3591 * callback on the result.
3592 */
3593 static void *
path_enumerate(const char * path,path_enum_proc callback,const char * refobj_path,void * arg)3594 path_enumerate(const char *path, path_enum_proc callback,
3595 const char *refobj_path, void *arg)
3596 {
3597 const char *trans;
3598 if (path == NULL)
3599 return (NULL);
3600
3601 path += strspn(path, ":;");
3602 while (*path != '\0') {
3603 size_t len;
3604 char *res;
3605
3606 len = strcspn(path, ":;");
3607 trans = lm_findn(refobj_path, path, len);
3608 if (trans)
3609 res = callback(trans, strlen(trans), arg);
3610 else
3611 res = callback(path, len, arg);
3612
3613 if (res != NULL)
3614 return (res);
3615
3616 path += len;
3617 path += strspn(path, ":;");
3618 }
3619
3620 return (NULL);
3621 }
3622
3623 struct try_library_args {
3624 const char *name;
3625 size_t namelen;
3626 char *buffer;
3627 size_t buflen;
3628 int fd;
3629 };
3630
3631 static void *
try_library_path(const char * dir,size_t dirlen,void * param)3632 try_library_path(const char *dir, size_t dirlen, void *param)
3633 {
3634 struct try_library_args *arg;
3635 int fd;
3636
3637 arg = param;
3638 if (*dir == '/' || trust) {
3639 char *pathname;
3640
3641 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3642 return (NULL);
3643
3644 pathname = arg->buffer;
3645 strncpy(pathname, dir, dirlen);
3646 pathname[dirlen] = '/';
3647 strcpy(pathname + dirlen + 1, arg->name);
3648
3649 dbg(" Trying \"%s\"", pathname);
3650 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3651 if (fd >= 0) {
3652 dbg(" Opened \"%s\", fd %d", pathname, fd);
3653 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3654 strcpy(pathname, arg->buffer);
3655 arg->fd = fd;
3656 return (pathname);
3657 } else {
3658 dbg(" Failed to open \"%s\": %s", pathname,
3659 rtld_strerror(errno));
3660 }
3661 }
3662 return (NULL);
3663 }
3664
3665 static char *
search_library_path(const char * name,const char * path,const char * refobj_path,int * fdp)3666 search_library_path(const char *name, const char *path, const char *refobj_path,
3667 int *fdp)
3668 {
3669 char *p;
3670 struct try_library_args arg;
3671
3672 if (path == NULL)
3673 return (NULL);
3674
3675 arg.name = name;
3676 arg.namelen = strlen(name);
3677 arg.buffer = xmalloc(PATH_MAX);
3678 arg.buflen = PATH_MAX;
3679 arg.fd = -1;
3680
3681 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3682 *fdp = arg.fd;
3683
3684 free(arg.buffer);
3685
3686 return (p);
3687 }
3688
3689 /*
3690 * Finds the library with the given name using the directory descriptors
3691 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3692 *
3693 * Returns a freshly-opened close-on-exec file descriptor for the library,
3694 * or -1 if the library cannot be found.
3695 */
3696 static char *
search_library_pathfds(const char * name,const char * path,int * fdp)3697 search_library_pathfds(const char *name, const char *path, int *fdp)
3698 {
3699 char *envcopy, *fdstr, *found, *last_token;
3700 size_t len;
3701 int dirfd, fd;
3702
3703 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3704
3705 /* Don't load from user-specified libdirs into setuid binaries. */
3706 if (!trust)
3707 return (NULL);
3708
3709 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3710 if (path == NULL)
3711 return (NULL);
3712
3713 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3714 if (name[0] == '/') {
3715 dbg("Absolute path (%s) passed to %s", name, __func__);
3716 return (NULL);
3717 }
3718
3719 /*
3720 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3721 * copy of the path, as strtok_r rewrites separator tokens
3722 * with '\0'.
3723 */
3724 found = NULL;
3725 envcopy = xstrdup(path);
3726 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3727 fdstr = strtok_r(NULL, ":", &last_token)) {
3728 dirfd = parse_integer(fdstr);
3729 if (dirfd < 0) {
3730 _rtld_error("failed to parse directory FD: '%s'",
3731 fdstr);
3732 break;
3733 }
3734 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3735 if (fd >= 0) {
3736 *fdp = fd;
3737 len = strlen(fdstr) + strlen(name) + 3;
3738 found = xmalloc(len);
3739 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) <
3740 0) {
3741 _rtld_error("error generating '%d/%s'", dirfd,
3742 name);
3743 rtld_die();
3744 }
3745 dbg("open('%s') => %d", found, fd);
3746 break;
3747 }
3748 }
3749 free(envcopy);
3750
3751 return (found);
3752 }
3753
3754 int
dlclose(void * handle)3755 dlclose(void *handle)
3756 {
3757 RtldLockState lockstate;
3758 int error;
3759
3760 wlock_acquire(rtld_bind_lock, &lockstate);
3761 error = dlclose_locked(handle, &lockstate);
3762 lock_release(rtld_bind_lock, &lockstate);
3763 return (error);
3764 }
3765
3766 static int
dlclose_locked(void * handle,RtldLockState * lockstate)3767 dlclose_locked(void *handle, RtldLockState *lockstate)
3768 {
3769 Obj_Entry *root;
3770
3771 root = dlcheck(handle);
3772 if (root == NULL)
3773 return (-1);
3774 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3775 root->path);
3776
3777 /* Unreference the object and its dependencies. */
3778 root->dl_refcount--;
3779
3780 if (root->refcount == 1) {
3781 /*
3782 * The object will be no longer referenced, so we must unload
3783 * it. First, call the fini functions.
3784 */
3785 objlist_call_fini(&list_fini, root, lockstate);
3786
3787 unref_dag(root);
3788
3789 /* Finish cleaning up the newly-unreferenced objects. */
3790 GDB_STATE(RT_DELETE, &root->linkmap);
3791 unload_object(root, lockstate);
3792 GDB_STATE(RT_CONSISTENT, NULL);
3793 } else
3794 unref_dag(root);
3795
3796 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3797 return (0);
3798 }
3799
3800 char *
dlerror(void)3801 dlerror(void)
3802 {
3803 if (*(lockinfo.dlerror_seen()) != 0)
3804 return (NULL);
3805 *lockinfo.dlerror_seen() = 1;
3806 return (lockinfo.dlerror_loc());
3807 }
3808
3809 /*
3810 * This function is deprecated and has no effect.
3811 */
3812 void
dllockinit(void * context,void * (* _lock_create)(void * context)__unused,void (* _rlock_acquire)(void * lock)__unused,void (* _wlock_acquire)(void * lock)__unused,void (* _lock_release)(void * lock)__unused,void (* _lock_destroy)(void * lock)__unused,void (* context_destroy)(void * context))3813 dllockinit(void *context, void *(*_lock_create)(void *context)__unused,
3814 void (*_rlock_acquire)(void *lock) __unused,
3815 void (*_wlock_acquire)(void *lock) __unused,
3816 void (*_lock_release)(void *lock) __unused,
3817 void (*_lock_destroy)(void *lock) __unused,
3818 void (*context_destroy)(void *context))
3819 {
3820 static void *cur_context;
3821 static void (*cur_context_destroy)(void *);
3822
3823 /* Just destroy the context from the previous call, if necessary. */
3824 if (cur_context_destroy != NULL)
3825 cur_context_destroy(cur_context);
3826 cur_context = context;
3827 cur_context_destroy = context_destroy;
3828 }
3829
3830 void *
dlopen(const char * name,int mode)3831 dlopen(const char *name, int mode)
3832 {
3833 return (rtld_dlopen(name, -1, mode));
3834 }
3835
3836 void *
fdlopen(int fd,int mode)3837 fdlopen(int fd, int mode)
3838 {
3839 return (rtld_dlopen(NULL, fd, mode));
3840 }
3841
3842 static void *
rtld_dlopen(const char * name,int fd,int mode)3843 rtld_dlopen(const char *name, int fd, int mode)
3844 {
3845 RtldLockState lockstate;
3846 int lo_flags;
3847
3848 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3849 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3850 if (ld_tracing != NULL) {
3851 rlock_acquire(rtld_bind_lock, &lockstate);
3852 if (sigsetjmp(lockstate.env, 0) != 0)
3853 lock_upgrade(rtld_bind_lock, &lockstate);
3854 environ = __DECONST(char **,
3855 *get_program_var_addr("environ", &lockstate));
3856 lock_release(rtld_bind_lock, &lockstate);
3857 }
3858 lo_flags = RTLD_LO_DLOPEN;
3859 if (mode & RTLD_NODELETE)
3860 lo_flags |= RTLD_LO_NODELETE;
3861 if (mode & RTLD_NOLOAD)
3862 lo_flags |= RTLD_LO_NOLOAD;
3863 if (mode & RTLD_DEEPBIND)
3864 lo_flags |= RTLD_LO_DEEPBIND;
3865 if (ld_tracing != NULL)
3866 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3867
3868 return (dlopen_object(name, fd, obj_main, lo_flags,
3869 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3870 }
3871
3872 static void
dlopen_cleanup(Obj_Entry * obj,RtldLockState * lockstate)3873 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3874 {
3875 obj->dl_refcount--;
3876 unref_dag(obj);
3877 if (obj->refcount == 0)
3878 unload_object(obj, lockstate);
3879 }
3880
3881 static Obj_Entry *
dlopen_object(const char * name,int fd,Obj_Entry * refobj,int lo_flags,int mode,RtldLockState * lockstate)3882 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3883 int mode, RtldLockState *lockstate)
3884 {
3885 Obj_Entry *obj;
3886 Objlist initlist;
3887 RtldLockState mlockstate;
3888 int result;
3889
3890 dbg(
3891 "dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3892 name != NULL ? name : "<null>", fd,
3893 refobj == NULL ? "<null>" : refobj->path, lo_flags, mode);
3894 objlist_init(&initlist);
3895
3896 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3897 wlock_acquire(rtld_bind_lock, &mlockstate);
3898 lockstate = &mlockstate;
3899 }
3900 GDB_STATE(RT_ADD, NULL);
3901
3902 obj = NULL;
3903 if (name == NULL && fd == -1) {
3904 obj = obj_main;
3905 obj->refcount++;
3906 } else {
3907 obj = load_object(name, fd, refobj, lo_flags);
3908 }
3909
3910 if (obj != NULL) {
3911 obj->dl_refcount++;
3912 if ((mode & RTLD_GLOBAL) != 0 &&
3913 objlist_find(&list_global, obj) == NULL)
3914 objlist_push_tail(&list_global, obj);
3915
3916 if (!obj->init_done) {
3917 /* We loaded something new and have to init something.
3918 */
3919 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3920 obj->deepbind = true;
3921 result = 0;
3922 if ((lo_flags & (RTLD_LO_EARLY |
3923 RTLD_LO_IGNSTLS)) == 0 &&
3924 obj->static_tls && !allocate_tls_offset(obj)) {
3925 _rtld_error(
3926 "%s: No space available for static Thread Local Storage",
3927 obj->path);
3928 result = -1;
3929 }
3930 if (result != -1)
3931 result = load_needed_objects(obj,
3932 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY |
3933 RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
3934 init_dag(obj);
3935 ref_dag(obj);
3936 if (result != -1)
3937 result = rtld_verify_versions(&obj->dagmembers);
3938 if (result != -1 && ld_tracing)
3939 goto trace;
3940 if (result == -1 || relocate_object_dag(obj,
3941 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3942 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3943 lockstate) == -1) {
3944 dlopen_cleanup(obj, lockstate);
3945 obj = NULL;
3946 } else if ((lo_flags & RTLD_LO_EARLY) != 0) {
3947 /*
3948 * Do not call the init functions for early
3949 * loaded filtees. The image is still not
3950 * initialized enough for them to work.
3951 *
3952 * Our object is found by the global object list
3953 * and will be ordered among all init calls done
3954 * right before transferring control to main.
3955 */
3956 } else {
3957 /* Make list of init functions to call. */
3958 initlist_for_loaded_obj(obj, obj, &initlist);
3959 }
3960 /*
3961 * Process all no_delete or global objects here, given
3962 * them own DAGs to prevent their dependencies from
3963 * being unloaded. This has to be done after we have
3964 * loaded all of the dependencies, so that we do not
3965 * miss any.
3966 */
3967 if (obj != NULL)
3968 process_z(obj);
3969 } else {
3970 /*
3971 * Bump the reference counts for objects on this DAG. If
3972 * this is the first dlopen() call for the object that
3973 * was already loaded as a dependency, initialize the
3974 * dag starting at it.
3975 */
3976 init_dag(obj);
3977 ref_dag(obj);
3978
3979 if ((lo_flags & RTLD_LO_TRACE) != 0)
3980 goto trace;
3981 }
3982 if (obj != NULL &&
3983 ((lo_flags & RTLD_LO_NODELETE) != 0 || obj->z_nodelete) &&
3984 !obj->ref_nodel) {
3985 dbg("obj %s nodelete", obj->path);
3986 ref_dag(obj);
3987 obj->z_nodelete = obj->ref_nodel = true;
3988 }
3989 }
3990
3991 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3992 name);
3993 GDB_STATE(RT_CONSISTENT, obj ? &obj->linkmap : NULL);
3994
3995 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3996 map_stacks_exec(lockstate);
3997 if (obj != NULL)
3998 distribute_static_tls(&initlist);
3999 }
4000
4001 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) ==
4002 RTLD_NOW, (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
4003 lockstate) == -1) {
4004 objlist_clear(&initlist);
4005 dlopen_cleanup(obj, lockstate);
4006 if (lockstate == &mlockstate)
4007 lock_release(rtld_bind_lock, lockstate);
4008 return (NULL);
4009 }
4010
4011 if ((lo_flags & RTLD_LO_EARLY) == 0) {
4012 /* Call the init functions. */
4013 objlist_call_init(&initlist, lockstate);
4014 }
4015 objlist_clear(&initlist);
4016 if (lockstate == &mlockstate)
4017 lock_release(rtld_bind_lock, lockstate);
4018 return (obj);
4019 trace:
4020 trace_loaded_objects(obj, false);
4021 if (lockstate == &mlockstate)
4022 lock_release(rtld_bind_lock, lockstate);
4023 exit(0);
4024 }
4025
4026 static void *
do_dlsym(void * handle,const char * name,void * retaddr,const Ver_Entry * ve,int flags)4027 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
4028 int flags)
4029 {
4030 DoneList donelist;
4031 const Obj_Entry *obj, *defobj;
4032 const Elf_Sym *def;
4033 SymLook req;
4034 RtldLockState lockstate;
4035 tls_index ti;
4036 void *sym;
4037 int res;
4038
4039 def = NULL;
4040 defobj = NULL;
4041 symlook_init(&req, name);
4042 req.ventry = ve;
4043 req.flags = flags | SYMLOOK_IN_PLT;
4044 req.lockstate = &lockstate;
4045
4046 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
4047 rlock_acquire(rtld_bind_lock, &lockstate);
4048 if (sigsetjmp(lockstate.env, 0) != 0)
4049 lock_upgrade(rtld_bind_lock, &lockstate);
4050 if (handle == NULL || handle == RTLD_NEXT || handle == RTLD_DEFAULT ||
4051 handle == RTLD_SELF) {
4052 if ((obj = obj_from_addr(retaddr)) == NULL) {
4053 _rtld_error("Cannot determine caller's shared object");
4054 lock_release(rtld_bind_lock, &lockstate);
4055 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4056 return (NULL);
4057 }
4058 if (handle == NULL) { /* Just the caller's shared object. */
4059 res = symlook_obj(&req, obj);
4060 if (res == 0) {
4061 def = req.sym_out;
4062 defobj = req.defobj_out;
4063 }
4064 } else if (handle == RTLD_NEXT || /* Objects after caller's */
4065 handle == RTLD_SELF) { /* ... caller included */
4066 if (handle == RTLD_NEXT)
4067 obj = globallist_next(obj);
4068 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4069 if (obj->marker)
4070 continue;
4071 res = symlook_obj(&req, obj);
4072 if (res == 0) {
4073 if (def == NULL ||
4074 (ld_dynamic_weak &&
4075 ELF_ST_BIND(
4076 req.sym_out->st_info) !=
4077 STB_WEAK)) {
4078 def = req.sym_out;
4079 defobj = req.defobj_out;
4080 if (!ld_dynamic_weak ||
4081 ELF_ST_BIND(def->st_info) !=
4082 STB_WEAK)
4083 break;
4084 }
4085 }
4086 }
4087 /*
4088 * Search the dynamic linker itself, and possibly
4089 * resolve the symbol from there. This is how the
4090 * application links to dynamic linker services such as
4091 * dlopen. Note that we ignore ld_dynamic_weak == false
4092 * case, always overriding weak symbols by rtld
4093 * definitions.
4094 */
4095 if (def == NULL ||
4096 ELF_ST_BIND(def->st_info) == STB_WEAK) {
4097 res = symlook_obj(&req, &obj_rtld);
4098 if (res == 0) {
4099 def = req.sym_out;
4100 defobj = req.defobj_out;
4101 }
4102 }
4103 } else {
4104 assert(handle == RTLD_DEFAULT);
4105 res = symlook_default(&req, obj);
4106 if (res == 0) {
4107 defobj = req.defobj_out;
4108 def = req.sym_out;
4109 }
4110 }
4111 } else {
4112 if ((obj = dlcheck(handle)) == NULL) {
4113 lock_release(rtld_bind_lock, &lockstate);
4114 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4115 return (NULL);
4116 }
4117
4118 donelist_init(&donelist);
4119 if (obj->mainprog) {
4120 /* Handle obtained by dlopen(NULL, ...) implies global
4121 * scope. */
4122 res = symlook_global(&req, &donelist);
4123 if (res == 0) {
4124 def = req.sym_out;
4125 defobj = req.defobj_out;
4126 }
4127 /*
4128 * Search the dynamic linker itself, and possibly
4129 * resolve the symbol from there. This is how the
4130 * application links to dynamic linker services such as
4131 * dlopen.
4132 */
4133 if (def == NULL ||
4134 ELF_ST_BIND(def->st_info) == STB_WEAK) {
4135 res = symlook_obj(&req, &obj_rtld);
4136 if (res == 0) {
4137 def = req.sym_out;
4138 defobj = req.defobj_out;
4139 }
4140 }
4141 } else {
4142 /* Search the whole DAG rooted at the given object. */
4143 res = symlook_list(&req, &obj->dagmembers, &donelist);
4144 if (res == 0) {
4145 def = req.sym_out;
4146 defobj = req.defobj_out;
4147 }
4148 }
4149 }
4150
4151 if (def != NULL) {
4152 lock_release(rtld_bind_lock, &lockstate);
4153
4154 /*
4155 * The value required by the caller is derived from the value
4156 * of the symbol. this is simply the relocated value of the
4157 * symbol.
4158 */
4159 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
4160 sym = make_function_pointer(def, defobj);
4161 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
4162 sym = rtld_resolve_ifunc(defobj, def);
4163 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
4164 ti.ti_module = defobj->tlsindex;
4165 ti.ti_offset = def->st_value - TLS_DTV_OFFSET;
4166 sym = __tls_get_addr(&ti);
4167 } else
4168 sym = defobj->relocbase + def->st_value;
4169 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
4170 return (sym);
4171 }
4172
4173 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
4174 ve != NULL ? ve->name : "");
4175 lock_release(rtld_bind_lock, &lockstate);
4176 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4177 return (NULL);
4178 }
4179
4180 void *
dlsym(void * handle,const char * name)4181 dlsym(void *handle, const char *name)
4182 {
4183 return (do_dlsym(handle, name, __builtin_return_address(0), NULL,
4184 SYMLOOK_DLSYM));
4185 }
4186
4187 dlfunc_t
dlfunc(void * handle,const char * name)4188 dlfunc(void *handle, const char *name)
4189 {
4190 union {
4191 void *d;
4192 dlfunc_t f;
4193 } rv;
4194
4195 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
4196 SYMLOOK_DLSYM);
4197 return (rv.f);
4198 }
4199
4200 void *
dlvsym(void * handle,const char * name,const char * version)4201 dlvsym(void *handle, const char *name, const char *version)
4202 {
4203 Ver_Entry ventry;
4204
4205 ventry.name = version;
4206 ventry.file = NULL;
4207 ventry.hash = elf_hash(version);
4208 ventry.flags = 0;
4209 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry,
4210 SYMLOOK_DLSYM));
4211 }
4212
4213 int
_rtld_addr_phdr(const void * addr,struct dl_phdr_info * phdr_info)4214 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
4215 {
4216 const Obj_Entry *obj;
4217 RtldLockState lockstate;
4218
4219 rlock_acquire(rtld_bind_lock, &lockstate);
4220 obj = obj_from_addr(addr);
4221 if (obj == NULL) {
4222 _rtld_error("No shared object contains address");
4223 lock_release(rtld_bind_lock, &lockstate);
4224 return (0);
4225 }
4226 rtld_fill_dl_phdr_info(obj, phdr_info);
4227 lock_release(rtld_bind_lock, &lockstate);
4228 return (1);
4229 }
4230
4231 int
dladdr(const void * addr,Dl_info * info)4232 dladdr(const void *addr, Dl_info *info)
4233 {
4234 const Obj_Entry *obj;
4235 const Elf_Sym *def;
4236 void *symbol_addr;
4237 unsigned long symoffset;
4238 RtldLockState lockstate;
4239
4240 rlock_acquire(rtld_bind_lock, &lockstate);
4241 obj = obj_from_addr(addr);
4242 if (obj == NULL) {
4243 _rtld_error("No shared object contains address");
4244 lock_release(rtld_bind_lock, &lockstate);
4245 return (0);
4246 }
4247 info->dli_fname = obj->path;
4248 info->dli_fbase = obj->mapbase;
4249 info->dli_saddr = (void *)0;
4250 info->dli_sname = NULL;
4251
4252 /*
4253 * Walk the symbol list looking for the symbol whose address is
4254 * closest to the address sent in.
4255 */
4256 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
4257 def = obj->symtab + symoffset;
4258
4259 /*
4260 * For skip the symbol if st_shndx is either SHN_UNDEF or
4261 * SHN_COMMON.
4262 */
4263 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
4264 continue;
4265
4266 /*
4267 * If the symbol is greater than the specified address, or if it
4268 * is further away from addr than the current nearest symbol,
4269 * then reject it.
4270 */
4271 symbol_addr = obj->relocbase + def->st_value;
4272 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
4273 continue;
4274
4275 /* Update our idea of the nearest symbol. */
4276 info->dli_sname = obj->strtab + def->st_name;
4277 info->dli_saddr = symbol_addr;
4278
4279 /* Exact match? */
4280 if (info->dli_saddr == addr)
4281 break;
4282 }
4283 lock_release(rtld_bind_lock, &lockstate);
4284 return (1);
4285 }
4286
4287 int
dlinfo(void * handle,int request,void * p)4288 dlinfo(void *handle, int request, void *p)
4289 {
4290 const Obj_Entry *obj;
4291 RtldLockState lockstate;
4292 int error;
4293
4294 rlock_acquire(rtld_bind_lock, &lockstate);
4295
4296 if (handle == NULL || handle == RTLD_SELF) {
4297 void *retaddr;
4298
4299 retaddr = __builtin_return_address(0); /* __GNUC__ only */
4300 if ((obj = obj_from_addr(retaddr)) == NULL)
4301 _rtld_error("Cannot determine caller's shared object");
4302 } else
4303 obj = dlcheck(handle);
4304
4305 if (obj == NULL) {
4306 lock_release(rtld_bind_lock, &lockstate);
4307 return (-1);
4308 }
4309
4310 error = 0;
4311 switch (request) {
4312 case RTLD_DI_LINKMAP:
4313 *((struct link_map const **)p) = &obj->linkmap;
4314 break;
4315 case RTLD_DI_ORIGIN:
4316 error = rtld_dirname(obj->path, p);
4317 break;
4318
4319 case RTLD_DI_SERINFOSIZE:
4320 case RTLD_DI_SERINFO:
4321 error = do_search_info(obj, request, (struct dl_serinfo *)p);
4322 break;
4323
4324 default:
4325 _rtld_error("Invalid request %d passed to dlinfo()", request);
4326 error = -1;
4327 }
4328
4329 lock_release(rtld_bind_lock, &lockstate);
4330
4331 return (error);
4332 }
4333
4334 static void
rtld_fill_dl_phdr_info(const Obj_Entry * obj,struct dl_phdr_info * phdr_info)4335 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
4336 {
4337 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
4338 phdr_info->dlpi_name = obj->path;
4339 phdr_info->dlpi_phdr = obj->phdr;
4340 phdr_info->dlpi_phnum = obj->phnum;
4341 phdr_info->dlpi_tls_modid = obj->tlsindex;
4342 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(_tcb_get(),
4343 obj->tlsindex, 0, true);
4344 phdr_info->dlpi_adds = obj_loads;
4345 phdr_info->dlpi_subs = obj_loads - obj_count;
4346 }
4347
4348 /*
4349 * It's completely UB to actually use this, so extreme caution is advised. It's
4350 * probably not what you want.
4351 */
4352 int
_dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback,void * param)4353 _dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback, void *param)
4354 {
4355 struct dl_phdr_info phdr_info;
4356 Obj_Entry *obj;
4357 int error;
4358
4359 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;
4360 obj = globallist_next(obj)) {
4361 rtld_fill_dl_phdr_info(obj, &phdr_info);
4362 error = callback(&phdr_info, sizeof(phdr_info), param);
4363 if (error != 0)
4364 return (error);
4365 }
4366
4367 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4368 return (callback(&phdr_info, sizeof(phdr_info), param));
4369 }
4370
4371 int
dl_iterate_phdr(__dl_iterate_hdr_callback callback,void * param)4372 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
4373 {
4374 struct dl_phdr_info phdr_info;
4375 Obj_Entry *obj, marker;
4376 RtldLockState bind_lockstate, phdr_lockstate;
4377 int error;
4378
4379 init_marker(&marker);
4380 error = 0;
4381
4382 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
4383 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4384 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
4385 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
4386 rtld_fill_dl_phdr_info(obj, &phdr_info);
4387 hold_object(obj);
4388 lock_release(rtld_bind_lock, &bind_lockstate);
4389
4390 error = callback(&phdr_info, sizeof phdr_info, param);
4391
4392 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4393 unhold_object(obj);
4394 obj = globallist_next(&marker);
4395 TAILQ_REMOVE(&obj_list, &marker, next);
4396 if (error != 0) {
4397 lock_release(rtld_bind_lock, &bind_lockstate);
4398 lock_release(rtld_phdr_lock, &phdr_lockstate);
4399 return (error);
4400 }
4401 }
4402
4403 if (error == 0) {
4404 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4405 lock_release(rtld_bind_lock, &bind_lockstate);
4406 error = callback(&phdr_info, sizeof(phdr_info), param);
4407 }
4408 lock_release(rtld_phdr_lock, &phdr_lockstate);
4409 return (error);
4410 }
4411
4412 static void *
fill_search_info(const char * dir,size_t dirlen,void * param)4413 fill_search_info(const char *dir, size_t dirlen, void *param)
4414 {
4415 struct fill_search_info_args *arg;
4416
4417 arg = param;
4418
4419 if (arg->request == RTLD_DI_SERINFOSIZE) {
4420 arg->serinfo->dls_cnt++;
4421 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen +
4422 1;
4423 } else {
4424 struct dl_serpath *s_entry;
4425
4426 s_entry = arg->serpath;
4427 s_entry->dls_name = arg->strspace;
4428 s_entry->dls_flags = arg->flags;
4429
4430 strncpy(arg->strspace, dir, dirlen);
4431 arg->strspace[dirlen] = '\0';
4432
4433 arg->strspace += dirlen + 1;
4434 arg->serpath++;
4435 }
4436
4437 return (NULL);
4438 }
4439
4440 static int
do_search_info(const Obj_Entry * obj,int request,struct dl_serinfo * info)4441 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
4442 {
4443 struct dl_serinfo _info;
4444 struct fill_search_info_args args;
4445
4446 args.request = RTLD_DI_SERINFOSIZE;
4447 args.serinfo = &_info;
4448
4449 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
4450 _info.dls_cnt = 0;
4451
4452 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
4453 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
4454 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
4455 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL,
4456 &args);
4457 if (!obj->z_nodeflib)
4458 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
4459 &args);
4460
4461 if (request == RTLD_DI_SERINFOSIZE) {
4462 info->dls_size = _info.dls_size;
4463 info->dls_cnt = _info.dls_cnt;
4464 return (0);
4465 }
4466
4467 if (info->dls_cnt != _info.dls_cnt ||
4468 info->dls_size != _info.dls_size) {
4469 _rtld_error(
4470 "Uninitialized Dl_serinfo struct passed to dlinfo()");
4471 return (-1);
4472 }
4473
4474 args.request = RTLD_DI_SERINFO;
4475 args.serinfo = info;
4476 args.serpath = &info->dls_serpath[0];
4477 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4478
4479 args.flags = LA_SER_RUNPATH;
4480 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4481 return (-1);
4482
4483 args.flags = LA_SER_LIBPATH;
4484 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) !=
4485 NULL)
4486 return (-1);
4487
4488 args.flags = LA_SER_RUNPATH;
4489 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4490 return (-1);
4491
4492 args.flags = LA_SER_CONFIG;
4493 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL,
4494 &args) != NULL)
4495 return (-1);
4496
4497 args.flags = LA_SER_DEFAULT;
4498 if (!obj->z_nodeflib &&
4499 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
4500 &args) != NULL)
4501 return (-1);
4502 return (0);
4503 }
4504
4505 static int
rtld_dirname(const char * path,char * bname)4506 rtld_dirname(const char *path, char *bname)
4507 {
4508 const char *endp;
4509
4510 /* Empty or NULL string gets treated as "." */
4511 if (path == NULL || *path == '\0') {
4512 bname[0] = '.';
4513 bname[1] = '\0';
4514 return (0);
4515 }
4516
4517 /* Strip trailing slashes */
4518 endp = path + strlen(path) - 1;
4519 while (endp > path && *endp == '/')
4520 endp--;
4521
4522 /* Find the start of the dir */
4523 while (endp > path && *endp != '/')
4524 endp--;
4525
4526 /* Either the dir is "/" or there are no slashes */
4527 if (endp == path) {
4528 bname[0] = *endp == '/' ? '/' : '.';
4529 bname[1] = '\0';
4530 return (0);
4531 } else {
4532 do {
4533 endp--;
4534 } while (endp > path && *endp == '/');
4535 }
4536
4537 if (endp - path + 2 > PATH_MAX) {
4538 _rtld_error("Filename is too long: %s", path);
4539 return (-1);
4540 }
4541
4542 strncpy(bname, path, endp - path + 1);
4543 bname[endp - path + 1] = '\0';
4544 return (0);
4545 }
4546
4547 static int
rtld_dirname_abs(const char * path,char * base)4548 rtld_dirname_abs(const char *path, char *base)
4549 {
4550 char *last;
4551
4552 if (realpath(path, base) == NULL) {
4553 _rtld_error("realpath \"%s\" failed (%s)", path,
4554 rtld_strerror(errno));
4555 return (-1);
4556 }
4557 dbg("%s -> %s", path, base);
4558 last = strrchr(base, '/');
4559 if (last == NULL) {
4560 _rtld_error("non-abs result from realpath \"%s\"", path);
4561 return (-1);
4562 }
4563 if (last != base)
4564 *last = '\0';
4565 return (0);
4566 }
4567
4568 static void
linkmap_add(Obj_Entry * obj)4569 linkmap_add(Obj_Entry *obj)
4570 {
4571 struct link_map *l, *prev;
4572
4573 l = &obj->linkmap;
4574 l->l_name = obj->path;
4575 l->l_base = obj->mapbase;
4576 l->l_ld = obj->dynamic;
4577 l->l_addr = obj->relocbase;
4578
4579 if (r_debug.r_map == NULL) {
4580 r_debug.r_map = l;
4581 return;
4582 }
4583
4584 /*
4585 * Scan to the end of the list, but not past the entry for the
4586 * dynamic linker, which we want to keep at the very end.
4587 */
4588 for (prev = r_debug.r_map;
4589 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4590 prev = prev->l_next)
4591 ;
4592
4593 /* Link in the new entry. */
4594 l->l_prev = prev;
4595 l->l_next = prev->l_next;
4596 if (l->l_next != NULL)
4597 l->l_next->l_prev = l;
4598 prev->l_next = l;
4599 }
4600
4601 static void
linkmap_delete(Obj_Entry * obj)4602 linkmap_delete(Obj_Entry *obj)
4603 {
4604 struct link_map *l;
4605
4606 l = &obj->linkmap;
4607 if (l->l_prev == NULL) {
4608 if ((r_debug.r_map = l->l_next) != NULL)
4609 l->l_next->l_prev = NULL;
4610 return;
4611 }
4612
4613 if ((l->l_prev->l_next = l->l_next) != NULL)
4614 l->l_next->l_prev = l->l_prev;
4615 }
4616
4617 /*
4618 * Function for the debugger to set a breakpoint on to gain control.
4619 *
4620 * The two parameters allow the debugger to easily find and determine
4621 * what the runtime loader is doing and to whom it is doing it.
4622 *
4623 * When the loadhook trap is hit (r_debug_state, set at program
4624 * initialization), the arguments can be found on the stack:
4625 *
4626 * +8 struct link_map *m
4627 * +4 struct r_debug *rd
4628 * +0 RetAddr
4629 */
4630 void
r_debug_state(struct r_debug * rd __unused,struct link_map * m __unused)4631 r_debug_state(struct r_debug *rd __unused, struct link_map *m __unused)
4632 {
4633 /*
4634 * The following is a hack to force the compiler to emit calls to
4635 * this function, even when optimizing. If the function is empty,
4636 * the compiler is not obliged to emit any code for calls to it,
4637 * even when marked __noinline. However, gdb depends on those
4638 * calls being made.
4639 */
4640 __compiler_membar();
4641 }
4642
4643 /*
4644 * A function called after init routines have completed. This can be used to
4645 * break before a program's entry routine is called, and can be used when
4646 * main is not available in the symbol table.
4647 */
4648 void
_r_debug_postinit(struct link_map * m __unused)4649 _r_debug_postinit(struct link_map *m __unused)
4650 {
4651 /* See r_debug_state(). */
4652 __compiler_membar();
4653 }
4654
4655 static void
release_object(Obj_Entry * obj)4656 release_object(Obj_Entry *obj)
4657 {
4658 if (obj->holdcount > 0) {
4659 obj->unholdfree = true;
4660 return;
4661 }
4662 munmap(obj->mapbase, obj->mapsize);
4663 linkmap_delete(obj);
4664 obj_free(obj);
4665 }
4666
4667 /*
4668 * Get address of the pointer variable in the main program.
4669 * Prefer non-weak symbol over the weak one.
4670 */
4671 static const void **
get_program_var_addr(const char * name,RtldLockState * lockstate)4672 get_program_var_addr(const char *name, RtldLockState *lockstate)
4673 {
4674 SymLook req;
4675 DoneList donelist;
4676
4677 symlook_init(&req, name);
4678 req.lockstate = lockstate;
4679 donelist_init(&donelist);
4680 if (symlook_global(&req, &donelist) != 0)
4681 return (NULL);
4682 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4683 return ((const void **)make_function_pointer(req.sym_out,
4684 req.defobj_out));
4685 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4686 return ((const void **)rtld_resolve_ifunc(req.defobj_out,
4687 req.sym_out));
4688 else
4689 return ((const void **)(req.defobj_out->relocbase +
4690 req.sym_out->st_value));
4691 }
4692
4693 /*
4694 * Set a pointer variable in the main program to the given value. This
4695 * is used to set key variables such as "environ" before any of the
4696 * init functions are called.
4697 */
4698 static void
set_program_var(const char * name,const void * value)4699 set_program_var(const char *name, const void *value)
4700 {
4701 const void **addr;
4702
4703 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4704 dbg("\"%s\": *%p <-- %p", name, addr, value);
4705 *addr = value;
4706 }
4707 }
4708
4709 /*
4710 * Search the global objects, including dependencies and main object,
4711 * for the given symbol.
4712 */
4713 static int
symlook_global(SymLook * req,DoneList * donelist)4714 symlook_global(SymLook *req, DoneList *donelist)
4715 {
4716 SymLook req1;
4717 const Objlist_Entry *elm;
4718 int res;
4719
4720 symlook_init_from_req(&req1, req);
4721
4722 /* Search all objects loaded at program start up. */
4723 if (req->defobj_out == NULL || (ld_dynamic_weak &&
4724 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) {
4725 res = symlook_list(&req1, &list_main, donelist);
4726 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL ||
4727 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4728 req->sym_out = req1.sym_out;
4729 req->defobj_out = req1.defobj_out;
4730 assert(req->defobj_out != NULL);
4731 }
4732 }
4733
4734 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4735 STAILQ_FOREACH(elm, &list_global, link) {
4736 if (req->defobj_out != NULL && (!ld_dynamic_weak ||
4737 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4738 break;
4739 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4740 if (res == 0 && (req->defobj_out == NULL ||
4741 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4742 req->sym_out = req1.sym_out;
4743 req->defobj_out = req1.defobj_out;
4744 assert(req->defobj_out != NULL);
4745 }
4746 }
4747
4748 return (req->sym_out != NULL ? 0 : ESRCH);
4749 }
4750
4751 /*
4752 * Given a symbol name in a referencing object, find the corresponding
4753 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4754 * no definition was found. Returns a pointer to the Obj_Entry of the
4755 * defining object via the reference parameter DEFOBJ_OUT.
4756 */
4757 static int
symlook_default(SymLook * req,const Obj_Entry * refobj)4758 symlook_default(SymLook *req, const Obj_Entry *refobj)
4759 {
4760 DoneList donelist;
4761 const Objlist_Entry *elm;
4762 SymLook req1;
4763 int res;
4764
4765 donelist_init(&donelist);
4766 symlook_init_from_req(&req1, req);
4767
4768 /*
4769 * Look first in the referencing object if linked symbolically,
4770 * and similarly handle protected symbols.
4771 */
4772 res = symlook_obj(&req1, refobj);
4773 if (res == 0 && (refobj->symbolic ||
4774 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED ||
4775 refobj->deepbind)) {
4776 req->sym_out = req1.sym_out;
4777 req->defobj_out = req1.defobj_out;
4778 assert(req->defobj_out != NULL);
4779 }
4780 if (refobj->symbolic || req->defobj_out != NULL || refobj->deepbind)
4781 donelist_check(&donelist, refobj);
4782
4783 if (!refobj->deepbind)
4784 symlook_global(req, &donelist);
4785
4786 /* Search all dlopened DAGs containing the referencing object. */
4787 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4788 if (req->sym_out != NULL && (!ld_dynamic_weak ||
4789 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4790 break;
4791 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4792 if (res == 0 && (req->sym_out == NULL ||
4793 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4794 req->sym_out = req1.sym_out;
4795 req->defobj_out = req1.defobj_out;
4796 assert(req->defobj_out != NULL);
4797 }
4798 }
4799
4800 if (refobj->deepbind)
4801 symlook_global(req, &donelist);
4802
4803 /*
4804 * Search the dynamic linker itself, and possibly resolve the
4805 * symbol from there. This is how the application links to
4806 * dynamic linker services such as dlopen.
4807 */
4808 if (req->sym_out == NULL ||
4809 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4810 res = symlook_obj(&req1, &obj_rtld);
4811 if (res == 0) {
4812 req->sym_out = req1.sym_out;
4813 req->defobj_out = req1.defobj_out;
4814 assert(req->defobj_out != NULL);
4815 }
4816 }
4817
4818 return (req->sym_out != NULL ? 0 : ESRCH);
4819 }
4820
4821 static int
symlook_list(SymLook * req,const Objlist * objlist,DoneList * dlp)4822 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4823 {
4824 const Elf_Sym *def;
4825 const Obj_Entry *defobj;
4826 const Objlist_Entry *elm;
4827 SymLook req1;
4828 int res;
4829
4830 def = NULL;
4831 defobj = NULL;
4832 STAILQ_FOREACH(elm, objlist, link) {
4833 if (donelist_check(dlp, elm->obj))
4834 continue;
4835 symlook_init_from_req(&req1, req);
4836 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4837 if (def == NULL || (ld_dynamic_weak &&
4838 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4839 def = req1.sym_out;
4840 defobj = req1.defobj_out;
4841 if (!ld_dynamic_weak ||
4842 ELF_ST_BIND(def->st_info) != STB_WEAK)
4843 break;
4844 }
4845 }
4846 }
4847 if (def != NULL) {
4848 req->sym_out = def;
4849 req->defobj_out = defobj;
4850 return (0);
4851 }
4852 return (ESRCH);
4853 }
4854
4855 /*
4856 * Search the chain of DAGS cointed to by the given Needed_Entry
4857 * for a symbol of the given name. Each DAG is scanned completely
4858 * before advancing to the next one. Returns a pointer to the symbol,
4859 * or NULL if no definition was found.
4860 */
4861 static int
symlook_needed(SymLook * req,const Needed_Entry * needed,DoneList * dlp)4862 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4863 {
4864 const Elf_Sym *def;
4865 const Needed_Entry *n;
4866 const Obj_Entry *defobj;
4867 SymLook req1;
4868 int res;
4869
4870 def = NULL;
4871 defobj = NULL;
4872 symlook_init_from_req(&req1, req);
4873 for (n = needed; n != NULL; n = n->next) {
4874 if (n->obj == NULL || (res = symlook_list(&req1,
4875 &n->obj->dagmembers, dlp)) != 0)
4876 continue;
4877 if (def == NULL || (ld_dynamic_weak &&
4878 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4879 def = req1.sym_out;
4880 defobj = req1.defobj_out;
4881 if (!ld_dynamic_weak ||
4882 ELF_ST_BIND(def->st_info) != STB_WEAK)
4883 break;
4884 }
4885 }
4886 if (def != NULL) {
4887 req->sym_out = def;
4888 req->defobj_out = defobj;
4889 return (0);
4890 }
4891 return (ESRCH);
4892 }
4893
4894 static int
symlook_obj_load_filtees(SymLook * req,SymLook * req1,const Obj_Entry * obj,Needed_Entry * needed)4895 symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj,
4896 Needed_Entry *needed)
4897 {
4898 DoneList donelist;
4899 int flags;
4900
4901 flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0;
4902 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4903 donelist_init(&donelist);
4904 symlook_init_from_req(req1, req);
4905 return (symlook_needed(req1, needed, &donelist));
4906 }
4907
4908 /*
4909 * Search the symbol table of a single shared object for a symbol of
4910 * the given name and version, if requested. Returns a pointer to the
4911 * symbol, or NULL if no definition was found. If the object is
4912 * filter, return filtered symbol from filtee.
4913 *
4914 * The symbol's hash value is passed in for efficiency reasons; that
4915 * eliminates many recomputations of the hash value.
4916 */
4917 int
symlook_obj(SymLook * req,const Obj_Entry * obj)4918 symlook_obj(SymLook *req, const Obj_Entry *obj)
4919 {
4920 SymLook req1;
4921 int res, mres;
4922
4923 /*
4924 * If there is at least one valid hash at this point, we prefer to
4925 * use the faster GNU version if available.
4926 */
4927 if (obj->valid_hash_gnu)
4928 mres = symlook_obj1_gnu(req, obj);
4929 else if (obj->valid_hash_sysv)
4930 mres = symlook_obj1_sysv(req, obj);
4931 else
4932 return (EINVAL);
4933
4934 if (mres == 0) {
4935 if (obj->needed_filtees != NULL) {
4936 res = symlook_obj_load_filtees(req, &req1, obj,
4937 obj->needed_filtees);
4938 if (res == 0) {
4939 req->sym_out = req1.sym_out;
4940 req->defobj_out = req1.defobj_out;
4941 }
4942 return (res);
4943 }
4944 if (obj->needed_aux_filtees != NULL) {
4945 res = symlook_obj_load_filtees(req, &req1, obj,
4946 obj->needed_aux_filtees);
4947 if (res == 0) {
4948 req->sym_out = req1.sym_out;
4949 req->defobj_out = req1.defobj_out;
4950 return (res);
4951 }
4952 }
4953 }
4954 return (mres);
4955 }
4956
4957 /* Symbol match routine common to both hash functions */
4958 static bool
matched_symbol(SymLook * req,const Obj_Entry * obj,Sym_Match_Result * result,const unsigned long symnum)4959 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4960 const unsigned long symnum)
4961 {
4962 Elf_Versym verndx;
4963 const Elf_Sym *symp;
4964 const char *strp;
4965
4966 symp = obj->symtab + symnum;
4967 strp = obj->strtab + symp->st_name;
4968
4969 switch (ELF_ST_TYPE(symp->st_info)) {
4970 case STT_FUNC:
4971 case STT_NOTYPE:
4972 case STT_OBJECT:
4973 case STT_COMMON:
4974 case STT_GNU_IFUNC:
4975 if (symp->st_value == 0)
4976 return (false);
4977 /* fallthrough */
4978 case STT_TLS:
4979 if (symp->st_shndx != SHN_UNDEF)
4980 break;
4981 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4982 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4983 break;
4984 /* fallthrough */
4985 default:
4986 return (false);
4987 }
4988 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4989 return (false);
4990
4991 if (req->ventry == NULL) {
4992 if (obj->versyms != NULL) {
4993 verndx = VER_NDX(obj->versyms[symnum]);
4994 if (verndx > obj->vernum) {
4995 _rtld_error(
4996 "%s: symbol %s references wrong version %d",
4997 obj->path, obj->strtab + symnum, verndx);
4998 return (false);
4999 }
5000 /*
5001 * If we are not called from dlsym (i.e. this
5002 * is a normal relocation from unversioned
5003 * binary), accept the symbol immediately if
5004 * it happens to have first version after this
5005 * shared object became versioned. Otherwise,
5006 * if symbol is versioned and not hidden,
5007 * remember it. If it is the only symbol with
5008 * this name exported by the shared object, it
5009 * will be returned as a match by the calling
5010 * function. If symbol is global (verndx < 2)
5011 * accept it unconditionally.
5012 */
5013 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
5014 verndx == VER_NDX_GIVEN) {
5015 result->sym_out = symp;
5016 return (true);
5017 } else if (verndx >= VER_NDX_GIVEN) {
5018 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) ==
5019 0) {
5020 if (result->vsymp == NULL)
5021 result->vsymp = symp;
5022 result->vcount++;
5023 }
5024 return (false);
5025 }
5026 }
5027 result->sym_out = symp;
5028 return (true);
5029 }
5030 if (obj->versyms == NULL) {
5031 if (object_match_name(obj, req->ventry->name)) {
5032 _rtld_error(
5033 "%s: object %s should provide version %s for symbol %s",
5034 obj_rtld.path, obj->path, req->ventry->name,
5035 obj->strtab + symnum);
5036 return (false);
5037 }
5038 } else {
5039 verndx = VER_NDX(obj->versyms[symnum]);
5040 if (verndx > obj->vernum) {
5041 _rtld_error("%s: symbol %s references wrong version %d",
5042 obj->path, obj->strtab + symnum, verndx);
5043 return (false);
5044 }
5045 if (obj->vertab[verndx].hash != req->ventry->hash ||
5046 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
5047 /*
5048 * Version does not match. Look if this is a
5049 * global symbol and if it is not hidden. If
5050 * global symbol (verndx < 2) is available,
5051 * use it. Do not return symbol if we are
5052 * called by dlvsym, because dlvsym looks for
5053 * a specific version and default one is not
5054 * what dlvsym wants.
5055 */
5056 if ((req->flags & SYMLOOK_DLSYM) ||
5057 (verndx >= VER_NDX_GIVEN) ||
5058 (obj->versyms[symnum] & VER_NDX_HIDDEN))
5059 return (false);
5060 }
5061 }
5062 result->sym_out = symp;
5063 return (true);
5064 }
5065
5066 /*
5067 * Search for symbol using SysV hash function.
5068 * obj->buckets is known not to be NULL at this point; the test for this was
5069 * performed with the obj->valid_hash_sysv assignment.
5070 */
5071 static int
symlook_obj1_sysv(SymLook * req,const Obj_Entry * obj)5072 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
5073 {
5074 unsigned long symnum;
5075 Sym_Match_Result matchres;
5076
5077 matchres.sym_out = NULL;
5078 matchres.vsymp = NULL;
5079 matchres.vcount = 0;
5080
5081 for (symnum = obj->buckets[req->hash % obj->nbuckets];
5082 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
5083 if (symnum >= obj->nchains)
5084 return (ESRCH); /* Bad object */
5085
5086 if (matched_symbol(req, obj, &matchres, symnum)) {
5087 req->sym_out = matchres.sym_out;
5088 req->defobj_out = obj;
5089 return (0);
5090 }
5091 }
5092 if (matchres.vcount == 1) {
5093 req->sym_out = matchres.vsymp;
5094 req->defobj_out = obj;
5095 return (0);
5096 }
5097 return (ESRCH);
5098 }
5099
5100 /* Search for symbol using GNU hash function */
5101 static int
symlook_obj1_gnu(SymLook * req,const Obj_Entry * obj)5102 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
5103 {
5104 Elf_Addr bloom_word;
5105 const Elf32_Word *hashval;
5106 Elf32_Word bucket;
5107 Sym_Match_Result matchres;
5108 unsigned int h1, h2;
5109 unsigned long symnum;
5110
5111 matchres.sym_out = NULL;
5112 matchres.vsymp = NULL;
5113 matchres.vcount = 0;
5114
5115 /* Pick right bitmask word from Bloom filter array */
5116 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
5117 obj->maskwords_bm_gnu];
5118
5119 /* Calculate modulus word size of gnu hash and its derivative */
5120 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
5121 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
5122
5123 /* Filter out the "definitely not in set" queries */
5124 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
5125 return (ESRCH);
5126
5127 /* Locate hash chain and corresponding value element*/
5128 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
5129 if (bucket == 0)
5130 return (ESRCH);
5131 hashval = &obj->chain_zero_gnu[bucket];
5132 do {
5133 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
5134 symnum = hashval - obj->chain_zero_gnu;
5135 if (matched_symbol(req, obj, &matchres, symnum)) {
5136 req->sym_out = matchres.sym_out;
5137 req->defobj_out = obj;
5138 return (0);
5139 }
5140 }
5141 } while ((*hashval++ & 1) == 0);
5142 if (matchres.vcount == 1) {
5143 req->sym_out = matchres.vsymp;
5144 req->defobj_out = obj;
5145 return (0);
5146 }
5147 return (ESRCH);
5148 }
5149
5150 static void
trace_calc_fmts(const char ** main_local,const char ** fmt1,const char ** fmt2)5151 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2)
5152 {
5153 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME);
5154 if (*main_local == NULL)
5155 *main_local = "";
5156
5157 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1);
5158 if (*fmt1 == NULL)
5159 *fmt1 = "\t%o => %p (%x)\n";
5160
5161 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2);
5162 if (*fmt2 == NULL)
5163 *fmt2 = "\t%o (%x)\n";
5164 }
5165
5166 static void
trace_print_obj(Obj_Entry * obj,const char * name,const char * path,const char * main_local,const char * fmt1,const char * fmt2)5167 trace_print_obj(Obj_Entry *obj, const char *name, const char *path,
5168 const char *main_local, const char *fmt1, const char *fmt2)
5169 {
5170 const char *fmt;
5171 int c;
5172
5173 if (fmt1 == NULL)
5174 fmt = fmt2;
5175 else
5176 /* XXX bogus */
5177 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2;
5178
5179 while ((c = *fmt++) != '\0') {
5180 switch (c) {
5181 default:
5182 rtld_putchar(c);
5183 continue;
5184 case '\\':
5185 switch (c = *fmt) {
5186 case '\0':
5187 continue;
5188 case 'n':
5189 rtld_putchar('\n');
5190 break;
5191 case 't':
5192 rtld_putchar('\t');
5193 break;
5194 }
5195 break;
5196 case '%':
5197 switch (c = *fmt) {
5198 case '\0':
5199 continue;
5200 case '%':
5201 default:
5202 rtld_putchar(c);
5203 break;
5204 case 'A':
5205 rtld_putstr(main_local);
5206 break;
5207 case 'a':
5208 rtld_putstr(obj_main->path);
5209 break;
5210 case 'o':
5211 rtld_putstr(name);
5212 break;
5213 case 'p':
5214 rtld_putstr(path);
5215 break;
5216 case 'x':
5217 rtld_printf("%p",
5218 obj != NULL ? obj->mapbase : NULL);
5219 break;
5220 }
5221 break;
5222 }
5223 ++fmt;
5224 }
5225 }
5226
5227 static void
trace_loaded_objects(Obj_Entry * obj,bool show_preload)5228 trace_loaded_objects(Obj_Entry *obj, bool show_preload)
5229 {
5230 const char *fmt1, *fmt2, *main_local;
5231 const char *name, *path;
5232 bool first_spurious, list_containers;
5233
5234 trace_calc_fmts(&main_local, &fmt1, &fmt2);
5235 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL;
5236
5237 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5238 Needed_Entry *needed;
5239
5240 if (obj->marker)
5241 continue;
5242 if (list_containers && obj->needed != NULL)
5243 rtld_printf("%s:\n", obj->path);
5244 for (needed = obj->needed; needed; needed = needed->next) {
5245 if (needed->obj != NULL) {
5246 if (needed->obj->traced && !list_containers)
5247 continue;
5248 needed->obj->traced = true;
5249 path = needed->obj->path;
5250 } else
5251 path = "not found";
5252
5253 name = obj->strtab + needed->name;
5254 trace_print_obj(needed->obj, name, path, main_local,
5255 fmt1, fmt2);
5256 }
5257 }
5258
5259 if (show_preload) {
5260 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL)
5261 fmt2 = "\t%p (%x)\n";
5262 first_spurious = true;
5263
5264 TAILQ_FOREACH(obj, &obj_list, next) {
5265 if (obj->marker || obj == obj_main || obj->traced)
5266 continue;
5267
5268 if (list_containers && first_spurious) {
5269 rtld_printf("[preloaded]\n");
5270 first_spurious = false;
5271 }
5272
5273 Name_Entry *fname = STAILQ_FIRST(&obj->names);
5274 name = fname == NULL ? "<unknown>" : fname->name;
5275 trace_print_obj(obj, name, obj->path, main_local, NULL,
5276 fmt2);
5277 }
5278 }
5279 }
5280
5281 /*
5282 * Unload a dlopened object and its dependencies from memory and from
5283 * our data structures. It is assumed that the DAG rooted in the
5284 * object has already been unreferenced, and that the object has a
5285 * reference count of 0.
5286 */
5287 static void
unload_object(Obj_Entry * root,RtldLockState * lockstate)5288 unload_object(Obj_Entry *root, RtldLockState *lockstate)
5289 {
5290 Obj_Entry marker, *obj, *next;
5291
5292 assert(root->refcount == 0);
5293
5294 /*
5295 * Pass over the DAG removing unreferenced objects from
5296 * appropriate lists.
5297 */
5298 unlink_object(root);
5299
5300 /* Unmap all objects that are no longer referenced. */
5301 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
5302 next = TAILQ_NEXT(obj, next);
5303 if (obj->marker || obj->refcount != 0)
5304 continue;
5305 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize,
5306 0, obj->path);
5307 dbg("unloading \"%s\"", obj->path);
5308 /*
5309 * Unlink the object now to prevent new references from
5310 * being acquired while the bind lock is dropped in
5311 * recursive dlclose() invocations.
5312 */
5313 TAILQ_REMOVE(&obj_list, obj, next);
5314 obj_count--;
5315
5316 if (obj->filtees_loaded) {
5317 if (next != NULL) {
5318 init_marker(&marker);
5319 TAILQ_INSERT_BEFORE(next, &marker, next);
5320 unload_filtees(obj, lockstate);
5321 next = TAILQ_NEXT(&marker, next);
5322 TAILQ_REMOVE(&obj_list, &marker, next);
5323 } else
5324 unload_filtees(obj, lockstate);
5325 }
5326 release_object(obj);
5327 }
5328 }
5329
5330 static void
unlink_object(Obj_Entry * root)5331 unlink_object(Obj_Entry *root)
5332 {
5333 Objlist_Entry *elm;
5334
5335 if (root->refcount == 0) {
5336 /* Remove the object from the RTLD_GLOBAL list. */
5337 objlist_remove(&list_global, root);
5338
5339 /* Remove the object from all objects' DAG lists. */
5340 STAILQ_FOREACH(elm, &root->dagmembers, link) {
5341 objlist_remove(&elm->obj->dldags, root);
5342 if (elm->obj != root)
5343 unlink_object(elm->obj);
5344 }
5345 }
5346 }
5347
5348 static void
ref_dag(Obj_Entry * root)5349 ref_dag(Obj_Entry *root)
5350 {
5351 Objlist_Entry *elm;
5352
5353 assert(root->dag_inited);
5354 STAILQ_FOREACH(elm, &root->dagmembers, link)
5355 elm->obj->refcount++;
5356 }
5357
5358 static void
unref_dag(Obj_Entry * root)5359 unref_dag(Obj_Entry *root)
5360 {
5361 Objlist_Entry *elm;
5362
5363 assert(root->dag_inited);
5364 STAILQ_FOREACH(elm, &root->dagmembers, link)
5365 elm->obj->refcount--;
5366 }
5367
5368 /*
5369 * Common code for MD __tls_get_addr().
5370 */
5371 static void *
tls_get_addr_slow(struct tcb * tcb,int index,size_t offset,bool locked)5372 tls_get_addr_slow(struct tcb *tcb, int index, size_t offset, bool locked)
5373 {
5374 struct dtv *newdtv, *dtv;
5375 RtldLockState lockstate;
5376 int to_copy;
5377
5378 dtv = tcb->tcb_dtv;
5379 /* Check dtv generation in case new modules have arrived */
5380 if (dtv->dtv_gen != tls_dtv_generation) {
5381 if (!locked)
5382 wlock_acquire(rtld_bind_lock, &lockstate);
5383 newdtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5384 sizeof(struct dtv_slot));
5385 to_copy = dtv->dtv_size;
5386 if (to_copy > tls_max_index)
5387 to_copy = tls_max_index;
5388 memcpy(newdtv->dtv_slots, dtv->dtv_slots, to_copy *
5389 sizeof(struct dtv_slot));
5390 newdtv->dtv_gen = tls_dtv_generation;
5391 newdtv->dtv_size = tls_max_index;
5392 free(dtv);
5393 if (!locked)
5394 lock_release(rtld_bind_lock, &lockstate);
5395 dtv = tcb->tcb_dtv = newdtv;
5396 }
5397
5398 /* Dynamically allocate module TLS if necessary */
5399 if (dtv->dtv_slots[index - 1].dtvs_tls == 0) {
5400 /* Signal safe, wlock will block out signals. */
5401 if (!locked)
5402 wlock_acquire(rtld_bind_lock, &lockstate);
5403 if (!dtv->dtv_slots[index - 1].dtvs_tls)
5404 dtv->dtv_slots[index - 1].dtvs_tls =
5405 allocate_module_tls(tcb, index);
5406 if (!locked)
5407 lock_release(rtld_bind_lock, &lockstate);
5408 }
5409 return (dtv->dtv_slots[index - 1].dtvs_tls + offset);
5410 }
5411
5412 void *
tls_get_addr_common(struct tcb * tcb,int index,size_t offset)5413 tls_get_addr_common(struct tcb *tcb, int index, size_t offset)
5414 {
5415 struct dtv *dtv;
5416
5417 dtv = tcb->tcb_dtv;
5418 /* Check dtv generation in case new modules have arrived */
5419 if (__predict_true(dtv->dtv_gen == tls_dtv_generation &&
5420 dtv->dtv_slots[index - 1].dtvs_tls != 0))
5421 return (dtv->dtv_slots[index - 1].dtvs_tls + offset);
5422 return (tls_get_addr_slow(tcb, index, offset, false));
5423 }
5424
5425 static struct tcb *
tcb_from_tcb_list_entry(struct tcb_list_entry * tcbelm)5426 tcb_from_tcb_list_entry(struct tcb_list_entry *tcbelm)
5427 {
5428 #ifdef TLS_VARIANT_I
5429 return ((struct tcb *)((char *)tcbelm - tcb_list_entry_offset));
5430 #else
5431 return ((struct tcb *)((char *)tcbelm + tcb_list_entry_offset));
5432 #endif
5433 }
5434
5435 static struct tcb_list_entry *
tcb_list_entry_from_tcb(struct tcb * tcb)5436 tcb_list_entry_from_tcb(struct tcb *tcb)
5437 {
5438 #ifdef TLS_VARIANT_I
5439 return ((struct tcb_list_entry *)((char *)tcb + tcb_list_entry_offset));
5440 #else
5441 return ((struct tcb_list_entry *)((char *)tcb - tcb_list_entry_offset));
5442 #endif
5443 }
5444
5445 static void
tcb_list_insert(struct tcb * tcb)5446 tcb_list_insert(struct tcb *tcb)
5447 {
5448 struct tcb_list_entry *tcbelm;
5449
5450 tcbelm = tcb_list_entry_from_tcb(tcb);
5451 TAILQ_INSERT_TAIL(&tcb_list, tcbelm, next);
5452 }
5453
5454 static void
tcb_list_remove(struct tcb * tcb)5455 tcb_list_remove(struct tcb *tcb)
5456 {
5457 struct tcb_list_entry *tcbelm;
5458
5459 tcbelm = tcb_list_entry_from_tcb(tcb);
5460 TAILQ_REMOVE(&tcb_list, tcbelm, next);
5461 }
5462
5463 #ifdef TLS_VARIANT_I
5464
5465 /*
5466 * Return pointer to allocated TLS block
5467 */
5468 static void *
get_tls_block_ptr(void * tcb,size_t tcbsize)5469 get_tls_block_ptr(void *tcb, size_t tcbsize)
5470 {
5471 size_t extra_size, post_size, pre_size, tls_block_size;
5472 size_t tls_init_align;
5473
5474 tls_init_align = MAX(obj_main->tlsalign, 1);
5475
5476 /* Compute fragments sizes. */
5477 extra_size = tcbsize - TLS_TCB_SIZE;
5478 post_size = calculate_tls_post_size(tls_init_align);
5479 tls_block_size = tcbsize + post_size;
5480 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5481
5482 return ((char *)tcb - pre_size - extra_size);
5483 }
5484
5485 /*
5486 * Allocate Static TLS using the Variant I method.
5487 *
5488 * For details on the layout, see lib/libc/gen/tls.c.
5489 *
5490 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
5491 * it is based on tls_last_offset, and TLS offsets here are really TCB
5492 * offsets, whereas libc's tls_static_space is just the executable's static
5493 * TLS segment.
5494 *
5495 * NB: This differs from NetBSD's ld.elf_so, where TLS offsets are relative to
5496 * the end of the TCB.
5497 */
5498 void *
allocate_tls(Obj_Entry * objs,void * oldtcb,size_t tcbsize,size_t tcbalign)5499 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5500 {
5501 Obj_Entry *obj;
5502 char *tls_block;
5503 struct dtv *dtv;
5504 struct tcb *tcb;
5505 char *addr;
5506 size_t i;
5507 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
5508 size_t tls_init_align, tls_init_offset, tls_bss_offset;
5509
5510 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
5511 return (oldtcb);
5512
5513 assert(tcbsize >= TLS_TCB_SIZE);
5514 maxalign = MAX(tcbalign, tls_static_max_align);
5515 tls_init_align = MAX(obj_main->tlsalign, 1);
5516
5517 /* Compute fragments sizes. */
5518 extra_size = tcbsize - TLS_TCB_SIZE;
5519 post_size = calculate_tls_post_size(tls_init_align);
5520 tls_block_size = tcbsize + post_size;
5521 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5522 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE -
5523 post_size;
5524
5525 /* Allocate whole TLS block */
5526 tls_block = xmalloc_aligned(tls_block_size, maxalign, 0);
5527 tcb = (struct tcb *)(tls_block + pre_size + extra_size);
5528
5529 if (oldtcb != NULL) {
5530 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
5531 tls_static_space);
5532 free(get_tls_block_ptr(oldtcb, tcbsize));
5533
5534 /* Adjust the DTV. */
5535 dtv = tcb->tcb_dtv;
5536 for (i = 0; i < dtv->dtv_size; i++) {
5537 if ((uintptr_t)dtv->dtv_slots[i].dtvs_tls >=
5538 (uintptr_t)oldtcb &&
5539 (uintptr_t)dtv->dtv_slots[i].dtvs_tls <
5540 (uintptr_t)oldtcb + tls_static_space) {
5541 dtv->dtv_slots[i].dtvs_tls = (char *)tcb +
5542 (dtv->dtv_slots[i].dtvs_tls -
5543 (char *)oldtcb);
5544 }
5545 }
5546 } else {
5547 dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5548 sizeof(struct dtv_slot));
5549 tcb->tcb_dtv = dtv;
5550 dtv->dtv_gen = tls_dtv_generation;
5551 dtv->dtv_size = tls_max_index;
5552
5553 for (obj = globallist_curr(objs); obj != NULL;
5554 obj = globallist_next(obj)) {
5555 if (obj->tlsoffset == 0)
5556 continue;
5557 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
5558 addr = (char *)tcb + obj->tlsoffset;
5559 if (tls_init_offset > 0)
5560 memset(addr, 0, tls_init_offset);
5561 if (obj->tlsinitsize > 0) {
5562 memcpy(addr + tls_init_offset, obj->tlsinit,
5563 obj->tlsinitsize);
5564 }
5565 if (obj->tlssize > obj->tlsinitsize) {
5566 tls_bss_offset = tls_init_offset +
5567 obj->tlsinitsize;
5568 memset(addr + tls_bss_offset, 0,
5569 obj->tlssize - tls_bss_offset);
5570 }
5571 dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr;
5572 }
5573 }
5574
5575 tcb_list_insert(tcb);
5576 return (tcb);
5577 }
5578
5579 void
free_tls(void * tcb,size_t tcbsize,size_t tcbalign __unused)5580 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5581 {
5582 struct dtv *dtv;
5583 uintptr_t tlsstart, tlsend;
5584 size_t post_size;
5585 size_t i, tls_init_align __unused;
5586
5587 tcb_list_remove(tcb);
5588
5589 assert(tcbsize >= TLS_TCB_SIZE);
5590 tls_init_align = MAX(obj_main->tlsalign, 1);
5591
5592 /* Compute fragments sizes. */
5593 post_size = calculate_tls_post_size(tls_init_align);
5594
5595 tlsstart = (uintptr_t)tcb + TLS_TCB_SIZE + post_size;
5596 tlsend = (uintptr_t)tcb + tls_static_space;
5597
5598 dtv = ((struct tcb *)tcb)->tcb_dtv;
5599 for (i = 0; i < dtv->dtv_size; i++) {
5600 if (dtv->dtv_slots[i].dtvs_tls != NULL &&
5601 ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart ||
5602 (uintptr_t)dtv->dtv_slots[i].dtvs_tls >= tlsend)) {
5603 free(dtv->dtv_slots[i].dtvs_tls);
5604 }
5605 }
5606 free(dtv);
5607 free(get_tls_block_ptr(tcb, tcbsize));
5608 }
5609
5610 #endif /* TLS_VARIANT_I */
5611
5612 #ifdef TLS_VARIANT_II
5613
5614 /*
5615 * Allocate Static TLS using the Variant II method.
5616 */
5617 void *
allocate_tls(Obj_Entry * objs,void * oldtcb,size_t tcbsize,size_t tcbalign)5618 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5619 {
5620 Obj_Entry *obj;
5621 size_t size, ralign;
5622 char *tls_block;
5623 struct dtv *dtv, *olddtv;
5624 struct tcb *tcb;
5625 char *addr;
5626 size_t i;
5627
5628 ralign = tcbalign;
5629 if (tls_static_max_align > ralign)
5630 ralign = tls_static_max_align;
5631 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5632
5633 assert(tcbsize >= 2 * sizeof(uintptr_t));
5634 tls_block = xmalloc_aligned(size, ralign, 0 /* XXX */);
5635 dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index *
5636 sizeof(struct dtv_slot));
5637
5638 tcb = (struct tcb *)(tls_block + roundup(tls_static_space, ralign));
5639 tcb->tcb_self = tcb;
5640 tcb->tcb_dtv = dtv;
5641
5642 dtv->dtv_gen = tls_dtv_generation;
5643 dtv->dtv_size = tls_max_index;
5644
5645 if (oldtcb != NULL) {
5646 /*
5647 * Copy the static TLS block over whole.
5648 */
5649 memcpy((char *)tcb - tls_static_space,
5650 (const char *)oldtcb - tls_static_space,
5651 tls_static_space);
5652
5653 /*
5654 * If any dynamic TLS blocks have been created tls_get_addr(),
5655 * move them over.
5656 */
5657 olddtv = ((struct tcb *)oldtcb)->tcb_dtv;
5658 for (i = 0; i < olddtv->dtv_size; i++) {
5659 if ((uintptr_t)olddtv->dtv_slots[i].dtvs_tls <
5660 (uintptr_t)oldtcb - size ||
5661 (uintptr_t)olddtv->dtv_slots[i].dtvs_tls >
5662 (uintptr_t)oldtcb) {
5663 dtv->dtv_slots[i].dtvs_tls =
5664 olddtv->dtv_slots[i].dtvs_tls;
5665 olddtv->dtv_slots[i].dtvs_tls = NULL;
5666 }
5667 }
5668
5669 /*
5670 * We assume that this block was the one we created with
5671 * allocate_initial_tls().
5672 */
5673 free_tls(oldtcb, 2 * sizeof(uintptr_t), sizeof(uintptr_t));
5674 } else {
5675 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5676 if (obj->marker || obj->tlsoffset == 0)
5677 continue;
5678 addr = (char *)tcb - obj->tlsoffset;
5679 memset(addr + obj->tlsinitsize, 0, obj->tlssize -
5680 obj->tlsinitsize);
5681 if (obj->tlsinit) {
5682 memcpy(addr, obj->tlsinit, obj->tlsinitsize);
5683 obj->static_tls_copied = true;
5684 }
5685 dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr;
5686 }
5687 }
5688
5689 tcb_list_insert(tcb);
5690 return (tcb);
5691 }
5692
5693 void
free_tls(void * tcb,size_t tcbsize __unused,size_t tcbalign)5694 free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign)
5695 {
5696 struct dtv *dtv;
5697 size_t size, ralign;
5698 size_t i;
5699 uintptr_t tlsstart, tlsend;
5700
5701 tcb_list_remove(tcb);
5702
5703 /*
5704 * Figure out the size of the initial TLS block so that we can
5705 * find stuff which ___tls_get_addr() allocated dynamically.
5706 */
5707 ralign = tcbalign;
5708 if (tls_static_max_align > ralign)
5709 ralign = tls_static_max_align;
5710 size = roundup(tls_static_space, ralign);
5711
5712 dtv = ((struct tcb *)tcb)->tcb_dtv;
5713 tlsend = (uintptr_t)tcb;
5714 tlsstart = tlsend - size;
5715 for (i = 0; i < dtv->dtv_size; i++) {
5716 if (dtv->dtv_slots[i].dtvs_tls != NULL &&
5717 ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart ||
5718 (uintptr_t)dtv->dtv_slots[i].dtvs_tls > tlsend)) {
5719 free(dtv->dtv_slots[i].dtvs_tls);
5720 }
5721 }
5722
5723 free((void *)tlsstart);
5724 free(dtv);
5725 }
5726
5727 #endif /* TLS_VARIANT_II */
5728
5729 /*
5730 * Allocate TLS block for module with given index.
5731 */
5732 void *
allocate_module_tls(struct tcb * tcb,int index)5733 allocate_module_tls(struct tcb *tcb, int index)
5734 {
5735 Obj_Entry *obj;
5736 char *p;
5737
5738 TAILQ_FOREACH(obj, &obj_list, next) {
5739 if (obj->marker)
5740 continue;
5741 if (obj->tlsindex == index)
5742 break;
5743 }
5744 if (obj == NULL) {
5745 _rtld_error("Can't find module with TLS index %d", index);
5746 rtld_die();
5747 }
5748
5749 if (obj->tls_static) {
5750 #ifdef TLS_VARIANT_I
5751 p = (char *)tcb + obj->tlsoffset;
5752 #else
5753 p = (char *)tcb - obj->tlsoffset;
5754 #endif
5755 return (p);
5756 }
5757
5758 obj->tls_dynamic = true;
5759
5760 p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5761 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5762 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5763 return (p);
5764 }
5765
5766 static bool
allocate_tls_offset_common(size_t * offp,size_t tlssize,size_t tlsalign,size_t tlspoffset __unused)5767 allocate_tls_offset_common(size_t *offp, size_t tlssize, size_t tlsalign,
5768 size_t tlspoffset __unused)
5769 {
5770 size_t off;
5771
5772 if (tls_last_offset == 0)
5773 off = calculate_first_tls_offset(tlssize, tlsalign,
5774 tlspoffset);
5775 else
5776 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5777 tlssize, tlsalign, tlspoffset);
5778
5779 *offp = off;
5780 #ifdef TLS_VARIANT_I
5781 off += tlssize;
5782 #endif
5783
5784 /*
5785 * If we have already fixed the size of the static TLS block, we
5786 * must stay within that size. When allocating the static TLS, we
5787 * leave a small amount of space spare to be used for dynamically
5788 * loading modules which use static TLS.
5789 */
5790 if (tls_static_space != 0) {
5791 if (off > tls_static_space)
5792 return (false);
5793 } else if (tlsalign > tls_static_max_align) {
5794 tls_static_max_align = tlsalign;
5795 }
5796
5797 tls_last_offset = off;
5798 tls_last_size = tlssize;
5799
5800 return (true);
5801 }
5802
5803 bool
allocate_tls_offset(Obj_Entry * obj)5804 allocate_tls_offset(Obj_Entry *obj)
5805 {
5806 if (obj->tls_dynamic)
5807 return (false);
5808
5809 if (obj->tls_static)
5810 return (true);
5811
5812 if (obj->tlssize == 0) {
5813 obj->tls_static = true;
5814 return (true);
5815 }
5816
5817 if (!allocate_tls_offset_common(&obj->tlsoffset, obj->tlssize,
5818 obj->tlsalign, obj->tlspoffset))
5819 return (false);
5820
5821 obj->tls_static = true;
5822
5823 return (true);
5824 }
5825
5826 void
free_tls_offset(Obj_Entry * obj)5827 free_tls_offset(Obj_Entry *obj)
5828 {
5829 /*
5830 * If we were the last thing to allocate out of the static TLS
5831 * block, we give our space back to the 'allocator'. This is a
5832 * simplistic workaround to allow libGL.so.1 to be loaded and
5833 * unloaded multiple times.
5834 */
5835 size_t off = obj->tlsoffset;
5836
5837 #ifdef TLS_VARIANT_I
5838 off += obj->tlssize;
5839 #endif
5840 if (off == tls_last_offset) {
5841 tls_last_offset -= obj->tlssize;
5842 tls_last_size = 0;
5843 }
5844 }
5845
5846 void *
_rtld_allocate_tls(void * oldtcb,size_t tcbsize,size_t tcbalign)5847 _rtld_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign)
5848 {
5849 void *ret;
5850 RtldLockState lockstate;
5851
5852 wlock_acquire(rtld_bind_lock, &lockstate);
5853 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtcb,
5854 tcbsize, tcbalign);
5855 lock_release(rtld_bind_lock, &lockstate);
5856 return (ret);
5857 }
5858
5859 void
_rtld_free_tls(void * tcb,size_t tcbsize,size_t tcbalign)5860 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5861 {
5862 RtldLockState lockstate;
5863
5864 wlock_acquire(rtld_bind_lock, &lockstate);
5865 free_tls(tcb, tcbsize, tcbalign);
5866 lock_release(rtld_bind_lock, &lockstate);
5867 }
5868
5869 static void
object_add_name(Obj_Entry * obj,const char * name)5870 object_add_name(Obj_Entry *obj, const char *name)
5871 {
5872 Name_Entry *entry;
5873 size_t len;
5874
5875 len = strlen(name);
5876 entry = malloc(sizeof(Name_Entry) + len);
5877
5878 if (entry != NULL) {
5879 strcpy(entry->name, name);
5880 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5881 }
5882 }
5883
5884 static int
object_match_name(const Obj_Entry * obj,const char * name)5885 object_match_name(const Obj_Entry *obj, const char *name)
5886 {
5887 Name_Entry *entry;
5888
5889 STAILQ_FOREACH(entry, &obj->names, link) {
5890 if (strcmp(name, entry->name) == 0)
5891 return (1);
5892 }
5893 return (0);
5894 }
5895
5896 static Obj_Entry *
locate_dependency(const Obj_Entry * obj,const char * name)5897 locate_dependency(const Obj_Entry *obj, const char *name)
5898 {
5899 const Objlist_Entry *entry;
5900 const Needed_Entry *needed;
5901
5902 STAILQ_FOREACH(entry, &list_main, link) {
5903 if (object_match_name(entry->obj, name))
5904 return (entry->obj);
5905 }
5906
5907 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5908 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5909 (needed->obj != NULL && object_match_name(needed->obj,
5910 name))) {
5911 /*
5912 * If there is DT_NEEDED for the name we are looking
5913 * for, we are all set. Note that object might not be
5914 * found if dependency was not loaded yet, so the
5915 * function can return NULL here. This is expected and
5916 * handled properly by the caller.
5917 */
5918 return (needed->obj);
5919 }
5920 }
5921 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5922 obj->path, name);
5923 rtld_die();
5924 }
5925
5926 static int
check_object_provided_version(Obj_Entry * refobj,const Obj_Entry * depobj,const Elf_Vernaux * vna)5927 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5928 const Elf_Vernaux *vna)
5929 {
5930 const Elf_Verdef *vd;
5931 const char *vername;
5932
5933 vername = refobj->strtab + vna->vna_name;
5934 vd = depobj->verdef;
5935 if (vd == NULL) {
5936 _rtld_error("%s: version %s required by %s not defined",
5937 depobj->path, vername, refobj->path);
5938 return (-1);
5939 }
5940 for (;;) {
5941 if (vd->vd_version != VER_DEF_CURRENT) {
5942 _rtld_error(
5943 "%s: Unsupported version %d of Elf_Verdef entry",
5944 depobj->path, vd->vd_version);
5945 return (-1);
5946 }
5947 if (vna->vna_hash == vd->vd_hash) {
5948 const Elf_Verdaux *aux =
5949 (const Elf_Verdaux *)((const char *)vd +
5950 vd->vd_aux);
5951 if (strcmp(vername, depobj->strtab + aux->vda_name) ==
5952 0)
5953 return (0);
5954 }
5955 if (vd->vd_next == 0)
5956 break;
5957 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5958 }
5959 if (vna->vna_flags & VER_FLG_WEAK)
5960 return (0);
5961 _rtld_error("%s: version %s required by %s not found", depobj->path,
5962 vername, refobj->path);
5963 return (-1);
5964 }
5965
5966 static int
rtld_verify_object_versions(Obj_Entry * obj)5967 rtld_verify_object_versions(Obj_Entry *obj)
5968 {
5969 const Elf_Verneed *vn;
5970 const Elf_Verdef *vd;
5971 const Elf_Verdaux *vda;
5972 const Elf_Vernaux *vna;
5973 const Obj_Entry *depobj;
5974 int maxvernum, vernum;
5975
5976 if (obj->ver_checked)
5977 return (0);
5978 obj->ver_checked = true;
5979
5980 maxvernum = 0;
5981 /*
5982 * Walk over defined and required version records and figure out
5983 * max index used by any of them. Do very basic sanity checking
5984 * while there.
5985 */
5986 vn = obj->verneed;
5987 while (vn != NULL) {
5988 if (vn->vn_version != VER_NEED_CURRENT) {
5989 _rtld_error(
5990 "%s: Unsupported version %d of Elf_Verneed entry",
5991 obj->path, vn->vn_version);
5992 return (-1);
5993 }
5994 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5995 for (;;) {
5996 vernum = VER_NEED_IDX(vna->vna_other);
5997 if (vernum > maxvernum)
5998 maxvernum = vernum;
5999 if (vna->vna_next == 0)
6000 break;
6001 vna = (const Elf_Vernaux *)((const char *)vna +
6002 vna->vna_next);
6003 }
6004 if (vn->vn_next == 0)
6005 break;
6006 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
6007 }
6008
6009 vd = obj->verdef;
6010 while (vd != NULL) {
6011 if (vd->vd_version != VER_DEF_CURRENT) {
6012 _rtld_error(
6013 "%s: Unsupported version %d of Elf_Verdef entry",
6014 obj->path, vd->vd_version);
6015 return (-1);
6016 }
6017 vernum = VER_DEF_IDX(vd->vd_ndx);
6018 if (vernum > maxvernum)
6019 maxvernum = vernum;
6020 if (vd->vd_next == 0)
6021 break;
6022 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6023 }
6024
6025 if (maxvernum == 0)
6026 return (0);
6027
6028 /*
6029 * Store version information in array indexable by version index.
6030 * Verify that object version requirements are satisfied along the
6031 * way.
6032 */
6033 obj->vernum = maxvernum + 1;
6034 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
6035
6036 vd = obj->verdef;
6037 while (vd != NULL) {
6038 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
6039 vernum = VER_DEF_IDX(vd->vd_ndx);
6040 assert(vernum <= maxvernum);
6041 vda = (const Elf_Verdaux *)((const char *)vd +
6042 vd->vd_aux);
6043 obj->vertab[vernum].hash = vd->vd_hash;
6044 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
6045 obj->vertab[vernum].file = NULL;
6046 obj->vertab[vernum].flags = 0;
6047 }
6048 if (vd->vd_next == 0)
6049 break;
6050 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
6051 }
6052
6053 vn = obj->verneed;
6054 while (vn != NULL) {
6055 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
6056 if (depobj == NULL)
6057 return (-1);
6058 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
6059 for (;;) {
6060 if (check_object_provided_version(obj, depobj, vna))
6061 return (-1);
6062 vernum = VER_NEED_IDX(vna->vna_other);
6063 assert(vernum <= maxvernum);
6064 obj->vertab[vernum].hash = vna->vna_hash;
6065 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
6066 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
6067 obj->vertab[vernum].flags = (vna->vna_other &
6068 VER_NEED_HIDDEN) != 0 ? VER_INFO_HIDDEN : 0;
6069 if (vna->vna_next == 0)
6070 break;
6071 vna = (const Elf_Vernaux *)((const char *)vna +
6072 vna->vna_next);
6073 }
6074 if (vn->vn_next == 0)
6075 break;
6076 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
6077 }
6078 return (0);
6079 }
6080
6081 static int
rtld_verify_versions(const Objlist * objlist)6082 rtld_verify_versions(const Objlist *objlist)
6083 {
6084 Objlist_Entry *entry;
6085 int rc;
6086
6087 rc = 0;
6088 STAILQ_FOREACH(entry, objlist, link) {
6089 /*
6090 * Skip dummy objects or objects that have their version
6091 * requirements already checked.
6092 */
6093 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
6094 continue;
6095 if (rtld_verify_object_versions(entry->obj) == -1) {
6096 rc = -1;
6097 if (ld_tracing == NULL)
6098 break;
6099 }
6100 }
6101 if (rc == 0 || ld_tracing != NULL)
6102 rc = rtld_verify_object_versions(&obj_rtld);
6103 return (rc);
6104 }
6105
6106 const Ver_Entry *
fetch_ventry(const Obj_Entry * obj,unsigned long symnum)6107 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
6108 {
6109 Elf_Versym vernum;
6110
6111 if (obj->vertab) {
6112 vernum = VER_NDX(obj->versyms[symnum]);
6113 if (vernum >= obj->vernum) {
6114 _rtld_error("%s: symbol %s has wrong verneed value %d",
6115 obj->path, obj->strtab + symnum, vernum);
6116 } else if (obj->vertab[vernum].hash != 0) {
6117 return (&obj->vertab[vernum]);
6118 }
6119 }
6120 return (NULL);
6121 }
6122
6123 int
_rtld_get_stack_prot(void)6124 _rtld_get_stack_prot(void)
6125 {
6126 return (stack_prot);
6127 }
6128
6129 int
_rtld_is_dlopened(void * arg)6130 _rtld_is_dlopened(void *arg)
6131 {
6132 Obj_Entry *obj;
6133 RtldLockState lockstate;
6134 int res;
6135
6136 rlock_acquire(rtld_bind_lock, &lockstate);
6137 obj = dlcheck(arg);
6138 if (obj == NULL)
6139 obj = obj_from_addr(arg);
6140 if (obj == NULL) {
6141 _rtld_error("No shared object contains address");
6142 lock_release(rtld_bind_lock, &lockstate);
6143 return (-1);
6144 }
6145 res = obj->dlopened ? 1 : 0;
6146 lock_release(rtld_bind_lock, &lockstate);
6147 return (res);
6148 }
6149
6150 static int
obj_remap_relro(Obj_Entry * obj,int prot)6151 obj_remap_relro(Obj_Entry *obj, int prot)
6152 {
6153 const Elf_Phdr *ph;
6154 caddr_t relro_page;
6155 size_t relro_size;
6156
6157 for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) {
6158 if (ph->p_type != PT_GNU_RELRO)
6159 continue;
6160 relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
6161 relro_size = rtld_round_page(ph->p_vaddr + ph->p_memsz) -
6162 rtld_trunc_page(ph->p_vaddr);
6163 if (mprotect(relro_page, relro_size, prot) == -1) {
6164 _rtld_error(
6165 "%s: Cannot set relro protection to %#x: %s",
6166 obj->path, prot, rtld_strerror(errno));
6167 return (-1);
6168 }
6169 break;
6170 }
6171 return (0);
6172 }
6173
6174 static int
obj_disable_relro(Obj_Entry * obj)6175 obj_disable_relro(Obj_Entry *obj)
6176 {
6177 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
6178 }
6179
6180 static int
obj_enforce_relro(Obj_Entry * obj)6181 obj_enforce_relro(Obj_Entry *obj)
6182 {
6183 return (obj_remap_relro(obj, PROT_READ));
6184 }
6185
6186 static void
map_stacks_exec(RtldLockState * lockstate)6187 map_stacks_exec(RtldLockState *lockstate)
6188 {
6189 void (*thr_map_stacks_exec)(void);
6190
6191 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
6192 return;
6193 thr_map_stacks_exec = (void (*)(void))(
6194 uintptr_t)get_program_var_addr("__pthread_map_stacks_exec",
6195 lockstate);
6196 if (thr_map_stacks_exec != NULL) {
6197 stack_prot |= PROT_EXEC;
6198 thr_map_stacks_exec();
6199 }
6200 }
6201
6202 static void
distribute_static_tls(Objlist * list)6203 distribute_static_tls(Objlist *list)
6204 {
6205 struct tcb_list_entry *tcbelm;
6206 Objlist_Entry *objelm;
6207 struct tcb *tcb;
6208 Obj_Entry *obj;
6209 char *tlsbase;
6210
6211 STAILQ_FOREACH(objelm, list, link) {
6212 obj = objelm->obj;
6213 if (obj->marker || !obj->tls_static || obj->static_tls_copied)
6214 continue;
6215 TAILQ_FOREACH(tcbelm, &tcb_list, next) {
6216 tcb = tcb_from_tcb_list_entry(tcbelm);
6217 #ifdef TLS_VARIANT_I
6218 tlsbase = (char *)tcb + obj->tlsoffset;
6219 #else
6220 tlsbase = (char *)tcb - obj->tlsoffset;
6221 #endif
6222 memcpy(tlsbase, obj->tlsinit, obj->tlsinitsize);
6223 memset(tlsbase + obj->tlsinitsize, 0,
6224 obj->tlssize - obj->tlsinitsize);
6225 }
6226 obj->static_tls_copied = true;
6227 }
6228 }
6229
6230 void
symlook_init(SymLook * dst,const char * name)6231 symlook_init(SymLook *dst, const char *name)
6232 {
6233 bzero(dst, sizeof(*dst));
6234 dst->name = name;
6235 dst->hash = elf_hash(name);
6236 dst->hash_gnu = gnu_hash(name);
6237 }
6238
6239 static void
symlook_init_from_req(SymLook * dst,const SymLook * src)6240 symlook_init_from_req(SymLook *dst, const SymLook *src)
6241 {
6242 dst->name = src->name;
6243 dst->hash = src->hash;
6244 dst->hash_gnu = src->hash_gnu;
6245 dst->ventry = src->ventry;
6246 dst->flags = src->flags;
6247 dst->defobj_out = NULL;
6248 dst->sym_out = NULL;
6249 dst->lockstate = src->lockstate;
6250 }
6251
6252 static int
open_binary_fd(const char * argv0,bool search_in_path,const char ** binpath_res)6253 open_binary_fd(const char *argv0, bool search_in_path, const char **binpath_res)
6254 {
6255 char *binpath, *pathenv, *pe, *res1;
6256 const char *res;
6257 int fd;
6258
6259 binpath = NULL;
6260 res = NULL;
6261 if (search_in_path && strchr(argv0, '/') == NULL) {
6262 binpath = xmalloc(PATH_MAX);
6263 pathenv = getenv("PATH");
6264 if (pathenv == NULL) {
6265 _rtld_error("-p and no PATH environment variable");
6266 rtld_die();
6267 }
6268 pathenv = strdup(pathenv);
6269 if (pathenv == NULL) {
6270 _rtld_error("Cannot allocate memory");
6271 rtld_die();
6272 }
6273 fd = -1;
6274 errno = ENOENT;
6275 while ((pe = strsep(&pathenv, ":")) != NULL) {
6276 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
6277 continue;
6278 if (binpath[0] != '\0' &&
6279 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
6280 continue;
6281 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
6282 continue;
6283 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
6284 if (fd != -1 || errno != ENOENT) {
6285 res = binpath;
6286 break;
6287 }
6288 }
6289 free(pathenv);
6290 } else {
6291 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
6292 res = argv0;
6293 }
6294
6295 if (fd == -1) {
6296 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
6297 rtld_die();
6298 }
6299 if (res != NULL && res[0] != '/') {
6300 res1 = xmalloc(PATH_MAX);
6301 if (realpath(res, res1) != NULL) {
6302 if (res != argv0)
6303 free(__DECONST(char *, res));
6304 res = res1;
6305 } else {
6306 free(res1);
6307 }
6308 }
6309 *binpath_res = res;
6310 return (fd);
6311 }
6312
6313 /*
6314 * Parse a set of command-line arguments.
6315 */
6316 static int
parse_args(char * argv[],int argc,bool * use_pathp,int * fdp,const char ** argv0,bool * dir_ignore)6317 parse_args(char *argv[], int argc, bool *use_pathp, int *fdp,
6318 const char **argv0, bool *dir_ignore)
6319 {
6320 const char *arg;
6321 char machine[64];
6322 size_t sz;
6323 int arglen, fd, i, j, mib[2];
6324 char opt;
6325 bool seen_b, seen_f;
6326
6327 dbg("Parsing command-line arguments");
6328 *use_pathp = false;
6329 *fdp = -1;
6330 *dir_ignore = false;
6331 seen_b = seen_f = false;
6332
6333 for (i = 1; i < argc; i++) {
6334 arg = argv[i];
6335 dbg("argv[%d]: '%s'", i, arg);
6336
6337 /*
6338 * rtld arguments end with an explicit "--" or with the first
6339 * non-prefixed argument.
6340 */
6341 if (strcmp(arg, "--") == 0) {
6342 i++;
6343 break;
6344 }
6345 if (arg[0] != '-')
6346 break;
6347
6348 /*
6349 * All other arguments are single-character options that can
6350 * be combined, so we need to search through `arg` for them.
6351 */
6352 arglen = strlen(arg);
6353 for (j = 1; j < arglen; j++) {
6354 opt = arg[j];
6355 if (opt == 'h') {
6356 print_usage(argv[0]);
6357 _exit(0);
6358 } else if (opt == 'b') {
6359 if (seen_f) {
6360 _rtld_error("Both -b and -f specified");
6361 rtld_die();
6362 }
6363 if (j != arglen - 1) {
6364 _rtld_error("Invalid options: %s", arg);
6365 rtld_die();
6366 }
6367 i++;
6368 *argv0 = argv[i];
6369 seen_b = true;
6370 break;
6371 } else if (opt == 'd') {
6372 *dir_ignore = true;
6373 } else if (opt == 'f') {
6374 if (seen_b) {
6375 _rtld_error("Both -b and -f specified");
6376 rtld_die();
6377 }
6378
6379 /*
6380 * -f XX can be used to specify a
6381 * descriptor for the binary named at
6382 * the command line (i.e., the later
6383 * argument will specify the process
6384 * name but the descriptor is what
6385 * will actually be executed).
6386 *
6387 * -f must be the last option in the
6388 * group, e.g., -abcf <fd>.
6389 */
6390 if (j != arglen - 1) {
6391 _rtld_error("Invalid options: %s", arg);
6392 rtld_die();
6393 }
6394 i++;
6395 fd = parse_integer(argv[i]);
6396 if (fd == -1) {
6397 _rtld_error(
6398 "Invalid file descriptor: '%s'",
6399 argv[i]);
6400 rtld_die();
6401 }
6402 *fdp = fd;
6403 seen_f = true;
6404 break;
6405 } else if (opt == 'o') {
6406 struct ld_env_var_desc *l;
6407 char *n, *v;
6408 u_int ll;
6409
6410 if (j != arglen - 1) {
6411 _rtld_error("Invalid options: %s", arg);
6412 rtld_die();
6413 }
6414 i++;
6415 n = argv[i];
6416 v = strchr(n, '=');
6417 if (v == NULL) {
6418 _rtld_error("No '=' in -o parameter");
6419 rtld_die();
6420 }
6421 for (ll = 0; ll < nitems(ld_env_vars); ll++) {
6422 l = &ld_env_vars[ll];
6423 if (v - n == (ptrdiff_t)strlen(l->n) &&
6424 strncmp(n, l->n, v - n) == 0) {
6425 l->val = v + 1;
6426 break;
6427 }
6428 }
6429 if (ll == nitems(ld_env_vars)) {
6430 _rtld_error("Unknown LD_ option %s", n);
6431 rtld_die();
6432 }
6433 } else if (opt == 'p') {
6434 *use_pathp = true;
6435 } else if (opt == 'u') {
6436 u_int ll;
6437
6438 for (ll = 0; ll < nitems(ld_env_vars); ll++)
6439 ld_env_vars[ll].val = NULL;
6440 } else if (opt == 'v') {
6441 machine[0] = '\0';
6442 mib[0] = CTL_HW;
6443 mib[1] = HW_MACHINE;
6444 sz = sizeof(machine);
6445 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
6446 ld_elf_hints_path = ld_get_env_var(
6447 LD_ELF_HINTS_PATH);
6448 set_ld_elf_hints_path();
6449 rtld_printf(
6450 "FreeBSD ld-elf.so.1 %s\n"
6451 "FreeBSD_version %d\n"
6452 "Default lib path %s\n"
6453 "Hints lib path %s\n"
6454 "Env prefix %s\n"
6455 "Default hint file %s\n"
6456 "Hint file %s\n"
6457 "libmap file %s\n"
6458 "Optional static TLS size %zd bytes\n",
6459 machine, __FreeBSD_version,
6460 ld_standard_library_path, gethints(false),
6461 ld_env_prefix, ld_elf_hints_default,
6462 ld_elf_hints_path, ld_path_libmap_conf,
6463 ld_static_tls_extra);
6464 _exit(0);
6465 } else {
6466 _rtld_error("Invalid argument: '%s'", arg);
6467 print_usage(argv[0]);
6468 rtld_die();
6469 }
6470 }
6471 }
6472
6473 if (!seen_b)
6474 *argv0 = argv[i];
6475 return (i);
6476 }
6477
6478 /*
6479 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
6480 */
6481 static int
parse_integer(const char * str)6482 parse_integer(const char *str)
6483 {
6484 static const int RADIX = 10; /* XXXJA: possibly support hex? */
6485 const char *orig;
6486 int n;
6487 char c;
6488
6489 orig = str;
6490 n = 0;
6491 for (c = *str; c != '\0'; c = *++str) {
6492 if (c < '0' || c > '9')
6493 return (-1);
6494
6495 n *= RADIX;
6496 n += c - '0';
6497 }
6498
6499 /* Make sure we actually parsed something. */
6500 if (str == orig)
6501 return (-1);
6502 return (n);
6503 }
6504
6505 static void
print_usage(const char * argv0)6506 print_usage(const char *argv0)
6507 {
6508 rtld_printf(
6509 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n"
6510 "\n"
6511 "Options:\n"
6512 " -h Display this help message\n"
6513 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
6514 " -d Ignore lack of exec permissions for the binary\n"
6515 " -f <FD> Execute <FD> instead of searching for <binary>\n"
6516 " -o <OPT>=<VAL> Set LD_<OPT> to <VAL>, without polluting env\n"
6517 " -p Search in PATH for named binary\n"
6518 " -u Ignore LD_ environment variables\n"
6519 " -v Display identification information\n"
6520 " -- End of RTLD options\n"
6521 " <binary> Name of process to execute\n"
6522 " <args> Arguments to the executed process\n",
6523 argv0);
6524 }
6525
6526 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt }
6527 static const struct auxfmt {
6528 const char *name;
6529 const char *fmt;
6530 } auxfmts[] = {
6531 AUXFMT(AT_NULL, NULL),
6532 AUXFMT(AT_IGNORE, NULL),
6533 AUXFMT(AT_EXECFD, "%ld"),
6534 AUXFMT(AT_PHDR, "%p"),
6535 AUXFMT(AT_PHENT, "%lu"),
6536 AUXFMT(AT_PHNUM, "%lu"),
6537 AUXFMT(AT_PAGESZ, "%lu"),
6538 AUXFMT(AT_BASE, "%#lx"),
6539 AUXFMT(AT_FLAGS, "%#lx"),
6540 AUXFMT(AT_ENTRY, "%p"),
6541 AUXFMT(AT_NOTELF, NULL),
6542 AUXFMT(AT_UID, "%ld"),
6543 AUXFMT(AT_EUID, "%ld"),
6544 AUXFMT(AT_GID, "%ld"),
6545 AUXFMT(AT_EGID, "%ld"),
6546 AUXFMT(AT_EXECPATH, "%s"),
6547 AUXFMT(AT_CANARY, "%p"),
6548 AUXFMT(AT_CANARYLEN, "%lu"),
6549 AUXFMT(AT_OSRELDATE, "%lu"),
6550 AUXFMT(AT_NCPUS, "%lu"),
6551 AUXFMT(AT_PAGESIZES, "%p"),
6552 AUXFMT(AT_PAGESIZESLEN, "%lu"),
6553 AUXFMT(AT_TIMEKEEP, "%p"),
6554 AUXFMT(AT_STACKPROT, "%#lx"),
6555 AUXFMT(AT_EHDRFLAGS, "%#lx"),
6556 AUXFMT(AT_HWCAP, "%#lx"),
6557 AUXFMT(AT_HWCAP2, "%#lx"),
6558 AUXFMT(AT_BSDFLAGS, "%#lx"),
6559 AUXFMT(AT_ARGC, "%lu"),
6560 AUXFMT(AT_ARGV, "%p"),
6561 AUXFMT(AT_ENVC, "%p"),
6562 AUXFMT(AT_ENVV, "%p"),
6563 AUXFMT(AT_PS_STRINGS, "%p"),
6564 AUXFMT(AT_FXRNG, "%p"),
6565 AUXFMT(AT_KPRELOAD, "%p"),
6566 AUXFMT(AT_USRSTACKBASE, "%#lx"),
6567 AUXFMT(AT_USRSTACKLIM, "%#lx"),
6568 /* AT_CHERI_STATS */
6569 AUXFMT(AT_HWCAP3, "%#lx"),
6570 AUXFMT(AT_HWCAP4, "%#lx"),
6571
6572 };
6573
6574 static bool
is_ptr_fmt(const char * fmt)6575 is_ptr_fmt(const char *fmt)
6576 {
6577 char last;
6578
6579 last = fmt[strlen(fmt) - 1];
6580 return (last == 'p' || last == 's');
6581 }
6582
6583 static void
dump_auxv(Elf_Auxinfo ** aux_info)6584 dump_auxv(Elf_Auxinfo **aux_info)
6585 {
6586 Elf_Auxinfo *auxp;
6587 const struct auxfmt *fmt;
6588 int i;
6589
6590 for (i = 0; i < AT_COUNT; i++) {
6591 auxp = aux_info[i];
6592 if (auxp == NULL)
6593 continue;
6594 fmt = &auxfmts[i];
6595 if (fmt->fmt == NULL)
6596 continue;
6597 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name);
6598 if (is_ptr_fmt(fmt->fmt)) {
6599 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6600 auxp->a_un.a_ptr);
6601 } else {
6602 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6603 auxp->a_un.a_val);
6604 }
6605 rtld_fdprintf(STDOUT_FILENO, "\n");
6606 }
6607 }
6608
6609 const char *
rtld_get_var(const char * name)6610 rtld_get_var(const char *name)
6611 {
6612 const struct ld_env_var_desc *lvd;
6613 u_int i;
6614
6615 for (i = 0; i < nitems(ld_env_vars); i++) {
6616 lvd = &ld_env_vars[i];
6617 if (strcmp(lvd->n, name) == 0)
6618 return (lvd->val);
6619 }
6620 return (NULL);
6621 }
6622
6623 static void
rtld_recalc_dangerous_ld_env(void)6624 rtld_recalc_dangerous_ld_env(void)
6625 {
6626 /*
6627 * Never reset dangerous_ld_env back to false if rtld was ever
6628 * contaminated with it set to true.
6629 */
6630 dangerous_ld_env |= libmap_disable || libmap_override != NULL ||
6631 ld_library_path != NULL || ld_preload != NULL ||
6632 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak ||
6633 ld_get_env_var(LD_STATIC_TLS_EXTRA) != NULL;
6634 }
6635
6636 static void
rtld_recalc_debug(const char * ld_debug)6637 rtld_recalc_debug(const char *ld_debug)
6638 {
6639 if (ld_debug != NULL && *ld_debug != '\0')
6640 debug = 1;
6641 }
6642
6643 static void
rtld_set_var_debug(struct ld_env_var_desc * lvd)6644 rtld_set_var_debug(struct ld_env_var_desc *lvd)
6645 {
6646 rtld_recalc_debug(lvd->val);
6647 }
6648
6649 static void
rtld_set_var_library_path(struct ld_env_var_desc * lvd)6650 rtld_set_var_library_path(struct ld_env_var_desc *lvd)
6651 {
6652 ld_library_path = lvd->val;
6653 }
6654
6655 static void
rtld_set_var_library_path_fds(struct ld_env_var_desc * lvd)6656 rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd)
6657 {
6658 ld_library_dirs = lvd->val;
6659 }
6660
6661 static void
rtld_recalc_path_rpath(const char * library_path_rpath)6662 rtld_recalc_path_rpath(const char *library_path_rpath)
6663 {
6664 if (library_path_rpath != NULL) {
6665 if (library_path_rpath[0] == 'y' ||
6666 library_path_rpath[0] == 'Y' ||
6667 library_path_rpath[0] == '1')
6668 ld_library_path_rpath = true;
6669 else
6670 ld_library_path_rpath = false;
6671 } else {
6672 ld_library_path_rpath = false;
6673 }
6674 }
6675
6676 static void
rtld_set_var_library_path_rpath(struct ld_env_var_desc * lvd)6677 rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd)
6678 {
6679 rtld_recalc_path_rpath(lvd->val);
6680 }
6681
6682 static void
rtld_recalc_bind_not(const char * bind_not_val)6683 rtld_recalc_bind_not(const char *bind_not_val)
6684 {
6685 if (ld_bind_now == NULL)
6686 ld_bind_not = bind_not_val != NULL;
6687 }
6688
6689 static void
rtld_set_var_bind_now(struct ld_env_var_desc * lvd)6690 rtld_set_var_bind_now(struct ld_env_var_desc *lvd)
6691 {
6692 ld_bind_now = lvd->val;
6693 rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT));
6694 }
6695
6696 static void
rtld_set_var_bind_not(struct ld_env_var_desc * lvd)6697 rtld_set_var_bind_not(struct ld_env_var_desc *lvd)
6698 {
6699 rtld_recalc_bind_not(lvd->val);
6700 }
6701
6702 static void
rtld_set_var_dynamic_weak(struct ld_env_var_desc * lvd)6703 rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd)
6704 {
6705 ld_dynamic_weak = lvd->val == NULL;
6706 }
6707
6708 static void
rtld_set_var_loadfltr(struct ld_env_var_desc * lvd)6709 rtld_set_var_loadfltr(struct ld_env_var_desc *lvd)
6710 {
6711 ld_loadfltr = lvd->val != NULL;
6712 }
6713
6714 static void
rtld_set_var_libmap_disable(struct ld_env_var_desc * lvd)6715 rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd)
6716 {
6717 libmap_disable = lvd->val != NULL;
6718 }
6719
6720 int
rtld_set_var(const char * name,const char * val)6721 rtld_set_var(const char *name, const char *val)
6722 {
6723 RtldLockState lockstate;
6724 struct ld_env_var_desc *lvd;
6725 u_int i;
6726 int error;
6727
6728 error = ENOENT;
6729 wlock_acquire(rtld_bind_lock, &lockstate);
6730 for (i = 0; i < nitems(ld_env_vars); i++) {
6731 lvd = &ld_env_vars[i];
6732 if (strcmp(lvd->n, name) != 0)
6733 continue;
6734 if (!lvd->can_update || (lvd->unsecure && !trust)) {
6735 error = EPERM;
6736 break;
6737 }
6738 if (lvd->owned)
6739 free(__DECONST(char *, lvd->val));
6740 if (val != NULL)
6741 lvd->val = xstrdup(val);
6742 else
6743 lvd->val = NULL;
6744 lvd->owned = true;
6745 if (lvd->on_update != NULL)
6746 lvd->on_update(lvd);
6747 error = 0;
6748 break;
6749 }
6750 if (error == 0)
6751 rtld_recalc_dangerous_ld_env();
6752 lock_release(rtld_bind_lock, &lockstate);
6753 return (error);
6754 }
6755
6756 /*
6757 * Overrides for libc_pic-provided functions.
6758 */
6759
6760 int
__getosreldate(void)6761 __getosreldate(void)
6762 {
6763 size_t len;
6764 int oid[2];
6765 int error, osrel;
6766
6767 if (osreldate != 0)
6768 return (osreldate);
6769
6770 oid[0] = CTL_KERN;
6771 oid[1] = KERN_OSRELDATE;
6772 osrel = 0;
6773 len = sizeof(osrel);
6774 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
6775 if (error == 0 && osrel > 0 && len == sizeof(osrel))
6776 osreldate = osrel;
6777 return (osreldate);
6778 }
6779 const char *
rtld_strerror(int errnum)6780 rtld_strerror(int errnum)
6781 {
6782 if (errnum < 0 || errnum >= sys_nerr)
6783 return ("Unknown error");
6784 return (sys_errlist[errnum]);
6785 }
6786
6787 char *
getenv(const char * name)6788 getenv(const char *name)
6789 {
6790 return (__DECONST(char *, rtld_get_env_val(environ, name,
6791 strlen(name))));
6792 }
6793
6794 /* malloc */
6795 void *
malloc(size_t nbytes)6796 malloc(size_t nbytes)
6797 {
6798 return (__crt_malloc(nbytes));
6799 }
6800
6801 void *
calloc(size_t num,size_t size)6802 calloc(size_t num, size_t size)
6803 {
6804 return (__crt_calloc(num, size));
6805 }
6806
6807 void
free(void * cp)6808 free(void *cp)
6809 {
6810 __crt_free(cp);
6811 }
6812
6813 void *
realloc(void * cp,size_t nbytes)6814 realloc(void *cp, size_t nbytes)
6815 {
6816 return (__crt_realloc(cp, nbytes));
6817 }
6818
6819 extern int _rtld_version__FreeBSD_version __exported;
6820 int _rtld_version__FreeBSD_version = __FreeBSD_version;
6821
6822 extern char _rtld_version_laddr_offset __exported;
6823 char _rtld_version_laddr_offset;
6824
6825 extern char _rtld_version_dlpi_tls_data __exported;
6826 char _rtld_version_dlpi_tls_data;
6827