1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/fs/binfmt_elf.c
4 *
5 * These are the functions used to load ELF format executables as used
6 * on SVr4 machines. Information on the format may be found in the book
7 * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
8 * Tools".
9 *
10 * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
11 */
12
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/fs.h>
16 #include <linux/log2.h>
17 #include <linux/mm.h>
18 #include <linux/mman.h>
19 #include <linux/errno.h>
20 #include <linux/signal.h>
21 #include <linux/binfmts.h>
22 #include <linux/string.h>
23 #include <linux/file.h>
24 #include <linux/slab.h>
25 #include <linux/personality.h>
26 #include <linux/elfcore.h>
27 #include <linux/init.h>
28 #include <linux/highuid.h>
29 #include <linux/compiler.h>
30 #include <linux/highmem.h>
31 #include <linux/hugetlb.h>
32 #include <linux/pagemap.h>
33 #include <linux/vmalloc.h>
34 #include <linux/security.h>
35 #include <linux/random.h>
36 #include <linux/elf.h>
37 #include <linux/elf-randomize.h>
38 #include <linux/utsname.h>
39 #include <linux/coredump.h>
40 #include <linux/sched.h>
41 #include <linux/sched/coredump.h>
42 #include <linux/sched/task_stack.h>
43 #include <linux/sched/cputime.h>
44 #include <linux/sizes.h>
45 #include <linux/types.h>
46 #include <linux/cred.h>
47 #include <linux/dax.h>
48 #include <linux/uaccess.h>
49 #include <linux/rseq.h>
50 #include <asm/param.h>
51 #include <asm/page.h>
52
53 #ifndef ELF_COMPAT
54 #define ELF_COMPAT 0
55 #endif
56
57 #ifndef user_long_t
58 #define user_long_t long
59 #endif
60 #ifndef user_siginfo_t
61 #define user_siginfo_t siginfo_t
62 #endif
63
64 /* That's for binfmt_elf_fdpic to deal with */
65 #ifndef elf_check_fdpic
66 #define elf_check_fdpic(ex) false
67 #endif
68
69 static int load_elf_binary(struct linux_binprm *bprm);
70
71 #ifdef CONFIG_USELIB
72 static int load_elf_library(struct file *);
73 #else
74 #define load_elf_library NULL
75 #endif
76
77 /*
78 * If we don't support core dumping, then supply a NULL so we
79 * don't even try.
80 */
81 #ifdef CONFIG_ELF_CORE
82 static int elf_core_dump(struct coredump_params *cprm);
83 #else
84 #define elf_core_dump NULL
85 #endif
86
87 #if ELF_EXEC_PAGESIZE > PAGE_SIZE
88 #define ELF_MIN_ALIGN ELF_EXEC_PAGESIZE
89 #else
90 #define ELF_MIN_ALIGN PAGE_SIZE
91 #endif
92
93 #ifndef ELF_CORE_EFLAGS
94 #define ELF_CORE_EFLAGS 0
95 #endif
96
97 #define ELF_PAGESTART(_v) ((_v) & ~(int)(ELF_MIN_ALIGN-1))
98 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
99 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
100
101 static struct linux_binfmt elf_format = {
102 .module = THIS_MODULE,
103 .load_binary = load_elf_binary,
104 .load_shlib = load_elf_library,
105 #ifdef CONFIG_COREDUMP
106 .core_dump = elf_core_dump,
107 .min_coredump = ELF_EXEC_PAGESIZE,
108 #endif
109 };
110
111 #define BAD_ADDR(x) (unlikely((unsigned long)(x) >= TASK_SIZE))
112
113 /*
114 * We need to explicitly zero any trailing portion of the page that follows
115 * p_filesz when it ends before the page ends (e.g. bss), otherwise this
116 * memory will contain the junk from the file that should not be present.
117 */
padzero(unsigned long address)118 static int padzero(unsigned long address)
119 {
120 unsigned long nbyte;
121
122 nbyte = ELF_PAGEOFFSET(address);
123 if (nbyte) {
124 nbyte = ELF_MIN_ALIGN - nbyte;
125 if (clear_user((void __user *)address, nbyte))
126 return -EFAULT;
127 }
128 return 0;
129 }
130
131 /* Let's use some macros to make this stack manipulation a little clearer */
132 #ifdef CONFIG_STACK_GROWSUP
133 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
134 #define STACK_ROUND(sp, items) \
135 ((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
136 #define STACK_ALLOC(sp, len) ({ \
137 elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
138 old_sp; })
139 #else
140 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
141 #define STACK_ROUND(sp, items) \
142 (((unsigned long) (sp - items)) &~ 15UL)
143 #define STACK_ALLOC(sp, len) (sp -= len)
144 #endif
145
146 #ifndef ELF_BASE_PLATFORM
147 /*
148 * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
149 * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
150 * will be copied to the user stack in the same manner as AT_PLATFORM.
151 */
152 #define ELF_BASE_PLATFORM NULL
153 #endif
154
155 static int
create_elf_tables(struct linux_binprm * bprm,const struct elfhdr * exec,unsigned long interp_load_addr,unsigned long e_entry,unsigned long phdr_addr)156 create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec,
157 unsigned long interp_load_addr,
158 unsigned long e_entry, unsigned long phdr_addr)
159 {
160 struct mm_struct *mm = current->mm;
161 unsigned long p = bprm->p;
162 int argc = bprm->argc;
163 int envc = bprm->envc;
164 elf_addr_t __user *sp;
165 elf_addr_t __user *u_platform;
166 elf_addr_t __user *u_base_platform;
167 elf_addr_t __user *u_rand_bytes;
168 const char *k_platform = ELF_PLATFORM;
169 const char *k_base_platform = ELF_BASE_PLATFORM;
170 unsigned char k_rand_bytes[16];
171 int items;
172 elf_addr_t *elf_info;
173 elf_addr_t flags = 0;
174 int ei_index;
175 const struct cred *cred = current_cred();
176 struct vm_area_struct *vma;
177
178 /*
179 * In some cases (e.g. Hyper-Threading), we want to avoid L1
180 * evictions by the processes running on the same package. One
181 * thing we can do is to shuffle the initial stack for them.
182 */
183
184 p = arch_align_stack(p);
185
186 /*
187 * If this architecture has a platform capability string, copy it
188 * to userspace. In some cases (Sparc), this info is impossible
189 * for userspace to get any other way, in others (i386) it is
190 * merely difficult.
191 */
192 u_platform = NULL;
193 if (k_platform) {
194 size_t len = strlen(k_platform) + 1;
195
196 u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
197 if (copy_to_user(u_platform, k_platform, len))
198 return -EFAULT;
199 }
200
201 /*
202 * If this architecture has a "base" platform capability
203 * string, copy it to userspace.
204 */
205 u_base_platform = NULL;
206 if (k_base_platform) {
207 size_t len = strlen(k_base_platform) + 1;
208
209 u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
210 if (copy_to_user(u_base_platform, k_base_platform, len))
211 return -EFAULT;
212 }
213
214 /*
215 * Generate 16 random bytes for userspace PRNG seeding.
216 */
217 get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
218 u_rand_bytes = (elf_addr_t __user *)
219 STACK_ALLOC(p, sizeof(k_rand_bytes));
220 if (copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
221 return -EFAULT;
222
223 /* Create the ELF interpreter info */
224 elf_info = (elf_addr_t *)mm->saved_auxv;
225 /* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
226 #define NEW_AUX_ENT(id, val) \
227 do { \
228 *elf_info++ = id; \
229 *elf_info++ = val; \
230 } while (0)
231
232 #ifdef ARCH_DLINFO
233 /*
234 * ARCH_DLINFO must come first so PPC can do its special alignment of
235 * AUXV.
236 * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
237 * ARCH_DLINFO changes
238 */
239 ARCH_DLINFO;
240 #endif
241 NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
242 NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
243 NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
244 NEW_AUX_ENT(AT_PHDR, phdr_addr);
245 NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
246 NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
247 NEW_AUX_ENT(AT_BASE, interp_load_addr);
248 if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0)
249 flags |= AT_FLAGS_PRESERVE_ARGV0;
250 NEW_AUX_ENT(AT_FLAGS, flags);
251 NEW_AUX_ENT(AT_ENTRY, e_entry);
252 NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid));
253 NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid));
254 NEW_AUX_ENT(AT_GID, from_kgid_munged(cred->user_ns, cred->gid));
255 NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid));
256 NEW_AUX_ENT(AT_SECURE, bprm->secureexec);
257 NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
258 #ifdef ELF_HWCAP2
259 NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
260 #endif
261 #ifdef ELF_HWCAP3
262 NEW_AUX_ENT(AT_HWCAP3, ELF_HWCAP3);
263 #endif
264 #ifdef ELF_HWCAP4
265 NEW_AUX_ENT(AT_HWCAP4, ELF_HWCAP4);
266 #endif
267 NEW_AUX_ENT(AT_EXECFN, bprm->exec);
268 if (k_platform) {
269 NEW_AUX_ENT(AT_PLATFORM,
270 (elf_addr_t)(unsigned long)u_platform);
271 }
272 if (k_base_platform) {
273 NEW_AUX_ENT(AT_BASE_PLATFORM,
274 (elf_addr_t)(unsigned long)u_base_platform);
275 }
276 if (bprm->have_execfd) {
277 NEW_AUX_ENT(AT_EXECFD, bprm->execfd);
278 }
279 #ifdef CONFIG_RSEQ
280 NEW_AUX_ENT(AT_RSEQ_FEATURE_SIZE, offsetof(struct rseq, end));
281 NEW_AUX_ENT(AT_RSEQ_ALIGN, __alignof__(struct rseq));
282 #endif
283 #undef NEW_AUX_ENT
284 /* AT_NULL is zero; clear the rest too */
285 memset(elf_info, 0, (char *)mm->saved_auxv +
286 sizeof(mm->saved_auxv) - (char *)elf_info);
287
288 /* And advance past the AT_NULL entry. */
289 elf_info += 2;
290
291 ei_index = elf_info - (elf_addr_t *)mm->saved_auxv;
292 sp = STACK_ADD(p, ei_index);
293
294 items = (argc + 1) + (envc + 1) + 1;
295 bprm->p = STACK_ROUND(sp, items);
296
297 /* Point sp at the lowest address on the stack */
298 #ifdef CONFIG_STACK_GROWSUP
299 sp = (elf_addr_t __user *)bprm->p - items - ei_index;
300 bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
301 #else
302 sp = (elf_addr_t __user *)bprm->p;
303 #endif
304
305
306 /*
307 * Grow the stack manually; some architectures have a limit on how
308 * far ahead a user-space access may be in order to grow the stack.
309 */
310 if (mmap_write_lock_killable(mm))
311 return -EINTR;
312 vma = find_extend_vma_locked(mm, bprm->p);
313 mmap_write_unlock(mm);
314 if (!vma)
315 return -EFAULT;
316
317 /* Now, let's put argc (and argv, envp if appropriate) on the stack */
318 if (put_user(argc, sp++))
319 return -EFAULT;
320
321 /* Populate list of argv pointers back to argv strings. */
322 p = mm->arg_end = mm->arg_start;
323 while (argc-- > 0) {
324 size_t len;
325 if (put_user((elf_addr_t)p, sp++))
326 return -EFAULT;
327 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
328 if (!len || len > MAX_ARG_STRLEN)
329 return -EINVAL;
330 p += len;
331 }
332 if (put_user(0, sp++))
333 return -EFAULT;
334 mm->arg_end = p;
335
336 /* Populate list of envp pointers back to envp strings. */
337 mm->env_end = mm->env_start = p;
338 while (envc-- > 0) {
339 size_t len;
340 if (put_user((elf_addr_t)p, sp++))
341 return -EFAULT;
342 len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
343 if (!len || len > MAX_ARG_STRLEN)
344 return -EINVAL;
345 p += len;
346 }
347 if (put_user(0, sp++))
348 return -EFAULT;
349 mm->env_end = p;
350
351 /* Put the elf_info on the stack in the right place. */
352 if (copy_to_user(sp, mm->saved_auxv, ei_index * sizeof(elf_addr_t)))
353 return -EFAULT;
354 return 0;
355 }
356
357 /*
358 * Map "eppnt->p_filesz" bytes from "filep" offset "eppnt->p_offset"
359 * into memory at "addr". (Note that p_filesz is rounded up to the
360 * next page, so any extra bytes from the file must be wiped.)
361 */
elf_map(struct file * filep,unsigned long addr,const struct elf_phdr * eppnt,int prot,int type,unsigned long total_size)362 static unsigned long elf_map(struct file *filep, unsigned long addr,
363 const struct elf_phdr *eppnt, int prot, int type,
364 unsigned long total_size)
365 {
366 unsigned long map_addr;
367 unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
368 unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
369 addr = ELF_PAGESTART(addr);
370 size = ELF_PAGEALIGN(size);
371
372 /* mmap() will return -EINVAL if given a zero size, but a
373 * segment with zero filesize is perfectly valid */
374 if (!size)
375 return addr;
376
377 /*
378 * total_size is the size of the ELF (interpreter) image.
379 * The _first_ mmap needs to know the full size, otherwise
380 * randomization might put this image into an overlapping
381 * position with the ELF binary image. (since size < total_size)
382 * So we first map the 'big' image - and unmap the remainder at
383 * the end. (which unmap is needed for ELF images with holes.)
384 */
385 if (total_size) {
386 total_size = ELF_PAGEALIGN(total_size);
387 map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
388 if (!BAD_ADDR(map_addr))
389 vm_munmap(map_addr+size, total_size-size);
390 } else
391 map_addr = vm_mmap(filep, addr, size, prot, type, off);
392
393 if ((type & MAP_FIXED_NOREPLACE) &&
394 PTR_ERR((void *)map_addr) == -EEXIST)
395 pr_info("%d (%s): Uhuuh, elf segment at %px requested but the memory is mapped already\n",
396 task_pid_nr(current), current->comm, (void *)addr);
397
398 return(map_addr);
399 }
400
401 /*
402 * Map "eppnt->p_filesz" bytes from "filep" offset "eppnt->p_offset"
403 * into memory at "addr". Memory from "p_filesz" through "p_memsz"
404 * rounded up to the next page is zeroed.
405 */
elf_load(struct file * filep,unsigned long addr,const struct elf_phdr * eppnt,int prot,int type,unsigned long total_size)406 static unsigned long elf_load(struct file *filep, unsigned long addr,
407 const struct elf_phdr *eppnt, int prot, int type,
408 unsigned long total_size)
409 {
410 unsigned long zero_start, zero_end;
411 unsigned long map_addr;
412
413 if (eppnt->p_filesz) {
414 map_addr = elf_map(filep, addr, eppnt, prot, type, total_size);
415 if (BAD_ADDR(map_addr))
416 return map_addr;
417 if (eppnt->p_memsz > eppnt->p_filesz) {
418 zero_start = map_addr + ELF_PAGEOFFSET(eppnt->p_vaddr) +
419 eppnt->p_filesz;
420 zero_end = map_addr + ELF_PAGEOFFSET(eppnt->p_vaddr) +
421 eppnt->p_memsz;
422
423 /*
424 * Zero the end of the last mapped page but ignore
425 * any errors if the segment isn't writable.
426 */
427 if (padzero(zero_start) && (prot & PROT_WRITE))
428 return -EFAULT;
429 }
430 } else {
431 map_addr = zero_start = ELF_PAGESTART(addr);
432 zero_end = zero_start + ELF_PAGEOFFSET(eppnt->p_vaddr) +
433 eppnt->p_memsz;
434 }
435 if (eppnt->p_memsz > eppnt->p_filesz) {
436 /*
437 * Map the last of the segment.
438 * If the header is requesting these pages to be
439 * executable, honour that (ppc32 needs this).
440 */
441 int error;
442
443 zero_start = ELF_PAGEALIGN(zero_start);
444 zero_end = ELF_PAGEALIGN(zero_end);
445
446 error = vm_brk_flags(zero_start, zero_end - zero_start,
447 prot & PROT_EXEC ? VM_EXEC : 0);
448 if (error)
449 map_addr = error;
450 }
451 return map_addr;
452 }
453
454
total_mapping_size(const struct elf_phdr * phdr,int nr)455 static unsigned long total_mapping_size(const struct elf_phdr *phdr, int nr)
456 {
457 elf_addr_t min_addr = -1;
458 elf_addr_t max_addr = 0;
459 bool pt_load = false;
460 int i;
461
462 for (i = 0; i < nr; i++) {
463 if (phdr[i].p_type == PT_LOAD) {
464 min_addr = min(min_addr, ELF_PAGESTART(phdr[i].p_vaddr));
465 max_addr = max(max_addr, phdr[i].p_vaddr + phdr[i].p_memsz);
466 pt_load = true;
467 }
468 }
469 return pt_load ? (max_addr - min_addr) : 0;
470 }
471
elf_read(struct file * file,void * buf,size_t len,loff_t pos)472 static int elf_read(struct file *file, void *buf, size_t len, loff_t pos)
473 {
474 ssize_t rv;
475
476 rv = kernel_read(file, buf, len, &pos);
477 if (unlikely(rv != len)) {
478 return (rv < 0) ? rv : -EIO;
479 }
480 return 0;
481 }
482
maximum_alignment(struct elf_phdr * cmds,int nr)483 static unsigned long maximum_alignment(struct elf_phdr *cmds, int nr)
484 {
485 unsigned long alignment = 0;
486 int i;
487
488 for (i = 0; i < nr; i++) {
489 if (cmds[i].p_type == PT_LOAD) {
490 unsigned long p_align = cmds[i].p_align;
491
492 /* skip non-power of two alignments as invalid */
493 if (!is_power_of_2(p_align))
494 continue;
495 alignment = max(alignment, p_align);
496 }
497 }
498
499 /* ensure we align to at least one page */
500 return ELF_PAGEALIGN(alignment);
501 }
502
503 /**
504 * load_elf_phdrs() - load ELF program headers
505 * @elf_ex: ELF header of the binary whose program headers should be loaded
506 * @elf_file: the opened ELF binary file
507 *
508 * Loads ELF program headers from the binary file elf_file, which has the ELF
509 * header pointed to by elf_ex, into a newly allocated array. The caller is
510 * responsible for freeing the allocated data. Returns NULL upon failure.
511 */
load_elf_phdrs(const struct elfhdr * elf_ex,struct file * elf_file)512 static struct elf_phdr *load_elf_phdrs(const struct elfhdr *elf_ex,
513 struct file *elf_file)
514 {
515 struct elf_phdr *elf_phdata = NULL;
516 int retval = -1;
517 unsigned int size;
518
519 /*
520 * If the size of this structure has changed, then punt, since
521 * we will be doing the wrong thing.
522 */
523 if (elf_ex->e_phentsize != sizeof(struct elf_phdr))
524 goto out;
525
526 /* Sanity check the number of program headers... */
527 /* ...and their total size. */
528 size = sizeof(struct elf_phdr) * elf_ex->e_phnum;
529 if (size == 0 || size > 65536 || size > ELF_MIN_ALIGN)
530 goto out;
531
532 elf_phdata = kmalloc(size, GFP_KERNEL);
533 if (!elf_phdata)
534 goto out;
535
536 /* Read in the program headers */
537 retval = elf_read(elf_file, elf_phdata, size, elf_ex->e_phoff);
538
539 out:
540 if (retval) {
541 kfree(elf_phdata);
542 elf_phdata = NULL;
543 }
544 return elf_phdata;
545 }
546
547 #ifndef CONFIG_ARCH_BINFMT_ELF_STATE
548
549 /**
550 * struct arch_elf_state - arch-specific ELF loading state
551 *
552 * This structure is used to preserve architecture specific data during
553 * the loading of an ELF file, throughout the checking of architecture
554 * specific ELF headers & through to the point where the ELF load is
555 * known to be proceeding (ie. SET_PERSONALITY).
556 *
557 * This implementation is a dummy for architectures which require no
558 * specific state.
559 */
560 struct arch_elf_state {
561 };
562
563 #define INIT_ARCH_ELF_STATE {}
564
565 /**
566 * arch_elf_pt_proc() - check a PT_LOPROC..PT_HIPROC ELF program header
567 * @ehdr: The main ELF header
568 * @phdr: The program header to check
569 * @elf: The open ELF file
570 * @is_interp: True if the phdr is from the interpreter of the ELF being
571 * loaded, else false.
572 * @state: Architecture-specific state preserved throughout the process
573 * of loading the ELF.
574 *
575 * Inspects the program header phdr to validate its correctness and/or
576 * suitability for the system. Called once per ELF program header in the
577 * range PT_LOPROC to PT_HIPROC, for both the ELF being loaded and its
578 * interpreter.
579 *
580 * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
581 * with that return code.
582 */
arch_elf_pt_proc(struct elfhdr * ehdr,struct elf_phdr * phdr,struct file * elf,bool is_interp,struct arch_elf_state * state)583 static inline int arch_elf_pt_proc(struct elfhdr *ehdr,
584 struct elf_phdr *phdr,
585 struct file *elf, bool is_interp,
586 struct arch_elf_state *state)
587 {
588 /* Dummy implementation, always proceed */
589 return 0;
590 }
591
592 /**
593 * arch_check_elf() - check an ELF executable
594 * @ehdr: The main ELF header
595 * @has_interp: True if the ELF has an interpreter, else false.
596 * @interp_ehdr: The interpreter's ELF header
597 * @state: Architecture-specific state preserved throughout the process
598 * of loading the ELF.
599 *
600 * Provides a final opportunity for architecture code to reject the loading
601 * of the ELF & cause an exec syscall to return an error. This is called after
602 * all program headers to be checked by arch_elf_pt_proc have been.
603 *
604 * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
605 * with that return code.
606 */
arch_check_elf(struct elfhdr * ehdr,bool has_interp,struct elfhdr * interp_ehdr,struct arch_elf_state * state)607 static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp,
608 struct elfhdr *interp_ehdr,
609 struct arch_elf_state *state)
610 {
611 /* Dummy implementation, always proceed */
612 return 0;
613 }
614
615 #endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */
616
make_prot(u32 p_flags,struct arch_elf_state * arch_state,bool has_interp,bool is_interp)617 static inline int make_prot(u32 p_flags, struct arch_elf_state *arch_state,
618 bool has_interp, bool is_interp)
619 {
620 int prot = 0;
621
622 if (p_flags & PF_R)
623 prot |= PROT_READ;
624 if (p_flags & PF_W)
625 prot |= PROT_WRITE;
626 if (p_flags & PF_X)
627 prot |= PROT_EXEC;
628
629 return arch_elf_adjust_prot(prot, arch_state, has_interp, is_interp);
630 }
631
632 /* This is much more generalized than the library routine read function,
633 so we keep this separate. Technically the library read function
634 is only provided so that we can read a.out libraries that have
635 an ELF header */
636
load_elf_interp(struct elfhdr * interp_elf_ex,struct file * interpreter,unsigned long no_base,struct elf_phdr * interp_elf_phdata,struct arch_elf_state * arch_state)637 static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
638 struct file *interpreter,
639 unsigned long no_base, struct elf_phdr *interp_elf_phdata,
640 struct arch_elf_state *arch_state)
641 {
642 struct elf_phdr *eppnt;
643 unsigned long load_addr = 0;
644 int load_addr_set = 0;
645 unsigned long error = ~0UL;
646 unsigned long total_size;
647 int i;
648
649 /* First of all, some simple consistency checks */
650 if (interp_elf_ex->e_type != ET_EXEC &&
651 interp_elf_ex->e_type != ET_DYN)
652 goto out;
653 if (!elf_check_arch(interp_elf_ex) ||
654 elf_check_fdpic(interp_elf_ex))
655 goto out;
656 if (!interpreter->f_op->mmap)
657 goto out;
658
659 total_size = total_mapping_size(interp_elf_phdata,
660 interp_elf_ex->e_phnum);
661 if (!total_size) {
662 error = -EINVAL;
663 goto out;
664 }
665
666 eppnt = interp_elf_phdata;
667 for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
668 if (eppnt->p_type == PT_LOAD) {
669 int elf_type = MAP_PRIVATE;
670 int elf_prot = make_prot(eppnt->p_flags, arch_state,
671 true, true);
672 unsigned long vaddr = 0;
673 unsigned long k, map_addr;
674
675 vaddr = eppnt->p_vaddr;
676 if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
677 elf_type |= MAP_FIXED;
678 else if (no_base && interp_elf_ex->e_type == ET_DYN)
679 load_addr = -vaddr;
680
681 map_addr = elf_load(interpreter, load_addr + vaddr,
682 eppnt, elf_prot, elf_type, total_size);
683 total_size = 0;
684 error = map_addr;
685 if (BAD_ADDR(map_addr))
686 goto out;
687
688 if (!load_addr_set &&
689 interp_elf_ex->e_type == ET_DYN) {
690 load_addr = map_addr - ELF_PAGESTART(vaddr);
691 load_addr_set = 1;
692 }
693
694 /*
695 * Check to see if the section's size will overflow the
696 * allowed task size. Note that p_filesz must always be
697 * <= p_memsize so it's only necessary to check p_memsz.
698 */
699 k = load_addr + eppnt->p_vaddr;
700 if (BAD_ADDR(k) ||
701 eppnt->p_filesz > eppnt->p_memsz ||
702 eppnt->p_memsz > TASK_SIZE ||
703 TASK_SIZE - eppnt->p_memsz < k) {
704 error = -ENOMEM;
705 goto out;
706 }
707 }
708 }
709
710 error = load_addr;
711 out:
712 return error;
713 }
714
715 /*
716 * These are the functions used to load ELF style executables and shared
717 * libraries. There is no binary dependent code anywhere else.
718 */
719
parse_elf_property(const char * data,size_t * off,size_t datasz,struct arch_elf_state * arch,bool have_prev_type,u32 * prev_type)720 static int parse_elf_property(const char *data, size_t *off, size_t datasz,
721 struct arch_elf_state *arch,
722 bool have_prev_type, u32 *prev_type)
723 {
724 size_t o, step;
725 const struct gnu_property *pr;
726 int ret;
727
728 if (*off == datasz)
729 return -ENOENT;
730
731 if (WARN_ON_ONCE(*off > datasz || *off % ELF_GNU_PROPERTY_ALIGN))
732 return -EIO;
733 o = *off;
734 datasz -= *off;
735
736 if (datasz < sizeof(*pr))
737 return -ENOEXEC;
738 pr = (const struct gnu_property *)(data + o);
739 o += sizeof(*pr);
740 datasz -= sizeof(*pr);
741
742 if (pr->pr_datasz > datasz)
743 return -ENOEXEC;
744
745 WARN_ON_ONCE(o % ELF_GNU_PROPERTY_ALIGN);
746 step = round_up(pr->pr_datasz, ELF_GNU_PROPERTY_ALIGN);
747 if (step > datasz)
748 return -ENOEXEC;
749
750 /* Properties are supposed to be unique and sorted on pr_type: */
751 if (have_prev_type && pr->pr_type <= *prev_type)
752 return -ENOEXEC;
753 *prev_type = pr->pr_type;
754
755 ret = arch_parse_elf_property(pr->pr_type, data + o,
756 pr->pr_datasz, ELF_COMPAT, arch);
757 if (ret)
758 return ret;
759
760 *off = o + step;
761 return 0;
762 }
763
764 #define NOTE_DATA_SZ SZ_1K
765 #define NOTE_NAME_SZ (sizeof(NN_GNU_PROPERTY_TYPE_0))
766
parse_elf_properties(struct file * f,const struct elf_phdr * phdr,struct arch_elf_state * arch)767 static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
768 struct arch_elf_state *arch)
769 {
770 union {
771 struct elf_note nhdr;
772 char data[NOTE_DATA_SZ];
773 } note;
774 loff_t pos;
775 ssize_t n;
776 size_t off, datasz;
777 int ret;
778 bool have_prev_type;
779 u32 prev_type;
780
781 if (!IS_ENABLED(CONFIG_ARCH_USE_GNU_PROPERTY) || !phdr)
782 return 0;
783
784 /* load_elf_binary() shouldn't call us unless this is true... */
785 if (WARN_ON_ONCE(phdr->p_type != PT_GNU_PROPERTY))
786 return -ENOEXEC;
787
788 /* If the properties are crazy large, that's too bad (for now): */
789 if (phdr->p_filesz > sizeof(note))
790 return -ENOEXEC;
791
792 pos = phdr->p_offset;
793 n = kernel_read(f, ¬e, phdr->p_filesz, &pos);
794
795 BUILD_BUG_ON(sizeof(note) < sizeof(note.nhdr) + NOTE_NAME_SZ);
796 if (n < 0 || n < sizeof(note.nhdr) + NOTE_NAME_SZ)
797 return -EIO;
798
799 if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 ||
800 note.nhdr.n_namesz != NOTE_NAME_SZ ||
801 strncmp(note.data + sizeof(note.nhdr),
802 NN_GNU_PROPERTY_TYPE_0, n - sizeof(note.nhdr)))
803 return -ENOEXEC;
804
805 off = round_up(sizeof(note.nhdr) + NOTE_NAME_SZ,
806 ELF_GNU_PROPERTY_ALIGN);
807 if (off > n)
808 return -ENOEXEC;
809
810 if (note.nhdr.n_descsz > n - off)
811 return -ENOEXEC;
812 datasz = off + note.nhdr.n_descsz;
813
814 have_prev_type = false;
815 do {
816 ret = parse_elf_property(note.data, &off, datasz, arch,
817 have_prev_type, &prev_type);
818 have_prev_type = true;
819 } while (!ret);
820
821 return ret == -ENOENT ? 0 : ret;
822 }
823
load_elf_binary(struct linux_binprm * bprm)824 static int load_elf_binary(struct linux_binprm *bprm)
825 {
826 struct file *interpreter = NULL; /* to shut gcc up */
827 unsigned long load_bias = 0, phdr_addr = 0;
828 int first_pt_load = 1;
829 unsigned long error;
830 struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
831 struct elf_phdr *elf_property_phdata = NULL;
832 unsigned long elf_brk;
833 bool brk_moved = false;
834 int retval, i;
835 unsigned long elf_entry;
836 unsigned long e_entry;
837 unsigned long interp_load_addr = 0;
838 unsigned long start_code, end_code, start_data, end_data;
839 unsigned long reloc_func_desc __maybe_unused = 0;
840 int executable_stack = EXSTACK_DEFAULT;
841 struct elfhdr *elf_ex = (struct elfhdr *)bprm->buf;
842 struct elfhdr *interp_elf_ex = NULL;
843 struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE;
844 struct mm_struct *mm;
845 struct pt_regs *regs;
846
847 retval = -ENOEXEC;
848 /* First of all, some simple consistency checks */
849 if (memcmp(elf_ex->e_ident, ELFMAG, SELFMAG) != 0)
850 goto out;
851
852 if (elf_ex->e_type != ET_EXEC && elf_ex->e_type != ET_DYN)
853 goto out;
854 if (!elf_check_arch(elf_ex))
855 goto out;
856 if (elf_check_fdpic(elf_ex))
857 goto out;
858 if (!bprm->file->f_op->mmap)
859 goto out;
860
861 elf_phdata = load_elf_phdrs(elf_ex, bprm->file);
862 if (!elf_phdata)
863 goto out;
864
865 elf_ppnt = elf_phdata;
866 for (i = 0; i < elf_ex->e_phnum; i++, elf_ppnt++) {
867 char *elf_interpreter;
868
869 if (elf_ppnt->p_type == PT_GNU_PROPERTY) {
870 elf_property_phdata = elf_ppnt;
871 continue;
872 }
873
874 if (elf_ppnt->p_type != PT_INTERP)
875 continue;
876
877 /*
878 * This is the program interpreter used for shared libraries -
879 * for now assume that this is an a.out format binary.
880 */
881 retval = -ENOEXEC;
882 if (elf_ppnt->p_filesz > PATH_MAX || elf_ppnt->p_filesz < 2)
883 goto out_free_ph;
884
885 retval = -ENOMEM;
886 elf_interpreter = kmalloc(elf_ppnt->p_filesz, GFP_KERNEL);
887 if (!elf_interpreter)
888 goto out_free_ph;
889
890 retval = elf_read(bprm->file, elf_interpreter, elf_ppnt->p_filesz,
891 elf_ppnt->p_offset);
892 if (retval < 0)
893 goto out_free_interp;
894 /* make sure path is NULL terminated */
895 retval = -ENOEXEC;
896 if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
897 goto out_free_interp;
898
899 interpreter = open_exec(elf_interpreter);
900 kfree(elf_interpreter);
901 retval = PTR_ERR(interpreter);
902 if (IS_ERR(interpreter))
903 goto out_free_ph;
904
905 /*
906 * If the binary is not readable then enforce mm->dumpable = 0
907 * regardless of the interpreter's permissions.
908 */
909 would_dump(bprm, interpreter);
910
911 interp_elf_ex = kmalloc(sizeof(*interp_elf_ex), GFP_KERNEL);
912 if (!interp_elf_ex) {
913 retval = -ENOMEM;
914 goto out_free_file;
915 }
916
917 /* Get the exec headers */
918 retval = elf_read(interpreter, interp_elf_ex,
919 sizeof(*interp_elf_ex), 0);
920 if (retval < 0)
921 goto out_free_dentry;
922
923 break;
924
925 out_free_interp:
926 kfree(elf_interpreter);
927 goto out_free_ph;
928 }
929
930 elf_ppnt = elf_phdata;
931 for (i = 0; i < elf_ex->e_phnum; i++, elf_ppnt++)
932 switch (elf_ppnt->p_type) {
933 case PT_GNU_STACK:
934 if (elf_ppnt->p_flags & PF_X)
935 executable_stack = EXSTACK_ENABLE_X;
936 else
937 executable_stack = EXSTACK_DISABLE_X;
938 break;
939
940 case PT_LOPROC ... PT_HIPROC:
941 retval = arch_elf_pt_proc(elf_ex, elf_ppnt,
942 bprm->file, false,
943 &arch_state);
944 if (retval)
945 goto out_free_dentry;
946 break;
947 }
948
949 /* Some simple consistency checks for the interpreter */
950 if (interpreter) {
951 retval = -ELIBBAD;
952 /* Not an ELF interpreter */
953 if (memcmp(interp_elf_ex->e_ident, ELFMAG, SELFMAG) != 0)
954 goto out_free_dentry;
955 /* Verify the interpreter has a valid arch */
956 if (!elf_check_arch(interp_elf_ex) ||
957 elf_check_fdpic(interp_elf_ex))
958 goto out_free_dentry;
959
960 /* Load the interpreter program headers */
961 interp_elf_phdata = load_elf_phdrs(interp_elf_ex,
962 interpreter);
963 if (!interp_elf_phdata)
964 goto out_free_dentry;
965
966 /* Pass PT_LOPROC..PT_HIPROC headers to arch code */
967 elf_property_phdata = NULL;
968 elf_ppnt = interp_elf_phdata;
969 for (i = 0; i < interp_elf_ex->e_phnum; i++, elf_ppnt++)
970 switch (elf_ppnt->p_type) {
971 case PT_GNU_PROPERTY:
972 elf_property_phdata = elf_ppnt;
973 break;
974
975 case PT_LOPROC ... PT_HIPROC:
976 retval = arch_elf_pt_proc(interp_elf_ex,
977 elf_ppnt, interpreter,
978 true, &arch_state);
979 if (retval)
980 goto out_free_dentry;
981 break;
982 }
983 }
984
985 retval = parse_elf_properties(interpreter ?: bprm->file,
986 elf_property_phdata, &arch_state);
987 if (retval)
988 goto out_free_dentry;
989
990 /*
991 * Allow arch code to reject the ELF at this point, whilst it's
992 * still possible to return an error to the code that invoked
993 * the exec syscall.
994 */
995 retval = arch_check_elf(elf_ex,
996 !!interpreter, interp_elf_ex,
997 &arch_state);
998 if (retval)
999 goto out_free_dentry;
1000
1001 /* Flush all traces of the currently running executable */
1002 retval = begin_new_exec(bprm);
1003 if (retval)
1004 goto out_free_dentry;
1005
1006 /* Do this immediately, since STACK_TOP as used in setup_arg_pages
1007 may depend on the personality. */
1008 SET_PERSONALITY2(*elf_ex, &arch_state);
1009 if (elf_read_implies_exec(*elf_ex, executable_stack))
1010 current->personality |= READ_IMPLIES_EXEC;
1011
1012 const int snapshot_randomize_va_space = READ_ONCE(randomize_va_space);
1013 if (!(current->personality & ADDR_NO_RANDOMIZE) && snapshot_randomize_va_space)
1014 current->flags |= PF_RANDOMIZE;
1015
1016 setup_new_exec(bprm);
1017
1018 /* Do this so that we can load the interpreter, if need be. We will
1019 change some of these later */
1020 retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
1021 executable_stack);
1022 if (retval < 0)
1023 goto out_free_dentry;
1024
1025 elf_brk = 0;
1026
1027 start_code = ~0UL;
1028 end_code = 0;
1029 start_data = 0;
1030 end_data = 0;
1031
1032 /* Now we do a little grungy work by mmapping the ELF image into
1033 the correct location in memory. */
1034 for(i = 0, elf_ppnt = elf_phdata;
1035 i < elf_ex->e_phnum; i++, elf_ppnt++) {
1036 int elf_prot, elf_flags;
1037 unsigned long k, vaddr;
1038 unsigned long total_size = 0;
1039 unsigned long alignment;
1040
1041 if (elf_ppnt->p_type != PT_LOAD)
1042 continue;
1043
1044 elf_prot = make_prot(elf_ppnt->p_flags, &arch_state,
1045 !!interpreter, false);
1046
1047 elf_flags = MAP_PRIVATE;
1048
1049 vaddr = elf_ppnt->p_vaddr;
1050 /*
1051 * The first time through the loop, first_pt_load is true:
1052 * layout will be calculated. Once set, use MAP_FIXED since
1053 * we know we've already safely mapped the entire region with
1054 * MAP_FIXED_NOREPLACE in the once-per-binary logic following.
1055 */
1056 if (!first_pt_load) {
1057 elf_flags |= MAP_FIXED;
1058 } else if (elf_ex->e_type == ET_EXEC) {
1059 /*
1060 * This logic is run once for the first LOAD Program
1061 * Header for ET_EXEC binaries. No special handling
1062 * is needed.
1063 */
1064 elf_flags |= MAP_FIXED_NOREPLACE;
1065 } else if (elf_ex->e_type == ET_DYN) {
1066 /*
1067 * This logic is run once for the first LOAD Program
1068 * Header for ET_DYN binaries to calculate the
1069 * randomization (load_bias) for all the LOAD
1070 * Program Headers.
1071 */
1072
1073 /*
1074 * Calculate the entire size of the ELF mapping
1075 * (total_size), used for the initial mapping,
1076 * due to load_addr_set which is set to true later
1077 * once the initial mapping is performed.
1078 *
1079 * Note that this is only sensible when the LOAD
1080 * segments are contiguous (or overlapping). If
1081 * used for LOADs that are far apart, this would
1082 * cause the holes between LOADs to be mapped,
1083 * running the risk of having the mapping fail,
1084 * as it would be larger than the ELF file itself.
1085 *
1086 * As a result, only ET_DYN does this, since
1087 * some ET_EXEC (e.g. ia64) may have large virtual
1088 * memory holes between LOADs.
1089 *
1090 */
1091 total_size = total_mapping_size(elf_phdata,
1092 elf_ex->e_phnum);
1093 if (!total_size) {
1094 retval = -EINVAL;
1095 goto out_free_dentry;
1096 }
1097
1098 /* Calculate any requested alignment. */
1099 alignment = maximum_alignment(elf_phdata, elf_ex->e_phnum);
1100
1101 /**
1102 * DOC: PIE handling
1103 *
1104 * There are effectively two types of ET_DYN ELF
1105 * binaries: programs (i.e. PIE: ET_DYN with
1106 * PT_INTERP) and loaders (i.e. static PIE: ET_DYN
1107 * without PT_INTERP, usually the ELF interpreter
1108 * itself). Loaders must be loaded away from programs
1109 * since the program may otherwise collide with the
1110 * loader (especially for ET_EXEC which does not have
1111 * a randomized position).
1112 *
1113 * For example, to handle invocations of
1114 * "./ld.so someprog" to test out a new version of
1115 * the loader, the subsequent program that the
1116 * loader loads must avoid the loader itself, so
1117 * they cannot share the same load range. Sufficient
1118 * room for the brk must be allocated with the
1119 * loader as well, since brk must be available with
1120 * the loader.
1121 *
1122 * Therefore, programs are loaded offset from
1123 * ELF_ET_DYN_BASE and loaders are loaded into the
1124 * independently randomized mmap region (0 load_bias
1125 * without MAP_FIXED nor MAP_FIXED_NOREPLACE).
1126 *
1127 * See below for "brk" handling details, which is
1128 * also affected by program vs loader and ASLR.
1129 */
1130 if (interpreter) {
1131 /* On ET_DYN with PT_INTERP, we do the ASLR. */
1132 load_bias = ELF_ET_DYN_BASE;
1133 if (current->flags & PF_RANDOMIZE)
1134 load_bias += arch_mmap_rnd();
1135 /* Adjust alignment as requested. */
1136 if (alignment)
1137 load_bias &= ~(alignment - 1);
1138 elf_flags |= MAP_FIXED_NOREPLACE;
1139 } else {
1140 /*
1141 * For ET_DYN without PT_INTERP, we rely on
1142 * the architectures's (potentially ASLR) mmap
1143 * base address (via a load_bias of 0).
1144 *
1145 * When a large alignment is requested, we
1146 * must do the allocation at address "0" right
1147 * now to discover where things will load so
1148 * that we can adjust the resulting alignment.
1149 * In this case (load_bias != 0), we can use
1150 * MAP_FIXED_NOREPLACE to make sure the mapping
1151 * doesn't collide with anything.
1152 */
1153 if (alignment > ELF_MIN_ALIGN) {
1154 load_bias = elf_load(bprm->file, 0, elf_ppnt,
1155 elf_prot, elf_flags, total_size);
1156 if (BAD_ADDR(load_bias)) {
1157 retval = IS_ERR_VALUE(load_bias) ?
1158 PTR_ERR((void*)load_bias) : -EINVAL;
1159 goto out_free_dentry;
1160 }
1161 vm_munmap(load_bias, total_size);
1162 /* Adjust alignment as requested. */
1163 if (alignment)
1164 load_bias &= ~(alignment - 1);
1165 elf_flags |= MAP_FIXED_NOREPLACE;
1166 } else
1167 load_bias = 0;
1168 }
1169
1170 /*
1171 * Since load_bias is used for all subsequent loading
1172 * calculations, we must lower it by the first vaddr
1173 * so that the remaining calculations based on the
1174 * ELF vaddrs will be correctly offset. The result
1175 * is then page aligned.
1176 */
1177 load_bias = ELF_PAGESTART(load_bias - vaddr);
1178 }
1179
1180 error = elf_load(bprm->file, load_bias + vaddr, elf_ppnt,
1181 elf_prot, elf_flags, total_size);
1182 if (BAD_ADDR(error)) {
1183 retval = IS_ERR_VALUE(error) ?
1184 PTR_ERR((void*)error) : -EINVAL;
1185 goto out_free_dentry;
1186 }
1187
1188 if (first_pt_load) {
1189 first_pt_load = 0;
1190 if (elf_ex->e_type == ET_DYN) {
1191 load_bias += error -
1192 ELF_PAGESTART(load_bias + vaddr);
1193 reloc_func_desc = load_bias;
1194 }
1195 }
1196
1197 /*
1198 * Figure out which segment in the file contains the Program
1199 * Header table, and map to the associated memory address.
1200 */
1201 if (elf_ppnt->p_offset <= elf_ex->e_phoff &&
1202 elf_ex->e_phoff < elf_ppnt->p_offset + elf_ppnt->p_filesz) {
1203 phdr_addr = elf_ex->e_phoff - elf_ppnt->p_offset +
1204 elf_ppnt->p_vaddr;
1205 }
1206
1207 k = elf_ppnt->p_vaddr;
1208 if ((elf_ppnt->p_flags & PF_X) && k < start_code)
1209 start_code = k;
1210 if (start_data < k)
1211 start_data = k;
1212
1213 /*
1214 * Check to see if the section's size will overflow the
1215 * allowed task size. Note that p_filesz must always be
1216 * <= p_memsz so it is only necessary to check p_memsz.
1217 */
1218 if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
1219 elf_ppnt->p_memsz > TASK_SIZE ||
1220 TASK_SIZE - elf_ppnt->p_memsz < k) {
1221 /* set_brk can never work. Avoid overflows. */
1222 retval = -EINVAL;
1223 goto out_free_dentry;
1224 }
1225
1226 k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
1227
1228 if ((elf_ppnt->p_flags & PF_X) && end_code < k)
1229 end_code = k;
1230 if (end_data < k)
1231 end_data = k;
1232 k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
1233 if (k > elf_brk)
1234 elf_brk = k;
1235 }
1236
1237 e_entry = elf_ex->e_entry + load_bias;
1238 phdr_addr += load_bias;
1239 elf_brk += load_bias;
1240 start_code += load_bias;
1241 end_code += load_bias;
1242 start_data += load_bias;
1243 end_data += load_bias;
1244
1245 if (interpreter) {
1246 elf_entry = load_elf_interp(interp_elf_ex,
1247 interpreter,
1248 load_bias, interp_elf_phdata,
1249 &arch_state);
1250 if (!IS_ERR_VALUE(elf_entry)) {
1251 /*
1252 * load_elf_interp() returns relocation
1253 * adjustment
1254 */
1255 interp_load_addr = elf_entry;
1256 elf_entry += interp_elf_ex->e_entry;
1257 }
1258 if (BAD_ADDR(elf_entry)) {
1259 retval = IS_ERR_VALUE(elf_entry) ?
1260 (int)elf_entry : -EINVAL;
1261 goto out_free_dentry;
1262 }
1263 reloc_func_desc = interp_load_addr;
1264
1265 exe_file_allow_write_access(interpreter);
1266 fput(interpreter);
1267
1268 kfree(interp_elf_ex);
1269 kfree(interp_elf_phdata);
1270 } else {
1271 elf_entry = e_entry;
1272 if (BAD_ADDR(elf_entry)) {
1273 retval = -EINVAL;
1274 goto out_free_dentry;
1275 }
1276 }
1277
1278 kfree(elf_phdata);
1279
1280 set_binfmt(&elf_format);
1281
1282 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
1283 retval = ARCH_SETUP_ADDITIONAL_PAGES(bprm, elf_ex, !!interpreter);
1284 if (retval < 0)
1285 goto out;
1286 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
1287
1288 retval = create_elf_tables(bprm, elf_ex, interp_load_addr,
1289 e_entry, phdr_addr);
1290 if (retval < 0)
1291 goto out;
1292
1293 mm = current->mm;
1294 mm->end_code = end_code;
1295 mm->start_code = start_code;
1296 mm->start_data = start_data;
1297 mm->end_data = end_data;
1298 mm->start_stack = bprm->p;
1299
1300 /**
1301 * DOC: "brk" handling
1302 *
1303 * For architectures with ELF randomization, when executing a
1304 * loader directly (i.e. static PIE: ET_DYN without PT_INTERP),
1305 * move the brk area out of the mmap region and into the unused
1306 * ELF_ET_DYN_BASE region. Since "brk" grows up it may collide
1307 * early with the stack growing down or other regions being put
1308 * into the mmap region by the kernel (e.g. vdso).
1309 *
1310 * In the CONFIG_COMPAT_BRK case, though, everything is turned
1311 * off because we're not allowed to move the brk at all.
1312 */
1313 if (!IS_ENABLED(CONFIG_COMPAT_BRK) &&
1314 IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) &&
1315 elf_ex->e_type == ET_DYN && !interpreter) {
1316 elf_brk = ELF_ET_DYN_BASE;
1317 /* This counts as moving the brk, so let brk(2) know. */
1318 brk_moved = true;
1319 }
1320 mm->start_brk = mm->brk = ELF_PAGEALIGN(elf_brk);
1321
1322 if ((current->flags & PF_RANDOMIZE) && snapshot_randomize_va_space > 1) {
1323 /*
1324 * If we didn't move the brk to ELF_ET_DYN_BASE (above),
1325 * leave a gap between .bss and brk.
1326 */
1327 if (!brk_moved)
1328 mm->brk = mm->start_brk = mm->brk + PAGE_SIZE;
1329
1330 mm->brk = mm->start_brk = arch_randomize_brk(mm);
1331 brk_moved = true;
1332 }
1333
1334 #ifdef compat_brk_randomized
1335 if (brk_moved)
1336 current->brk_randomized = 1;
1337 #endif
1338
1339 if (current->personality & MMAP_PAGE_ZERO) {
1340 /* Why this, you ask??? Well SVr4 maps page 0 as read-only,
1341 and some applications "depend" upon this behavior.
1342 Since we do not have the power to recompile these, we
1343 emulate the SVr4 behavior. Sigh. */
1344 error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
1345 MAP_FIXED | MAP_PRIVATE, 0);
1346
1347 retval = do_mseal(0, PAGE_SIZE, 0);
1348 if (retval)
1349 pr_warn_ratelimited("pid=%d, couldn't seal address 0, ret=%d.\n",
1350 task_pid_nr(current), retval);
1351 }
1352
1353 regs = current_pt_regs();
1354 #ifdef ELF_PLAT_INIT
1355 /*
1356 * The ABI may specify that certain registers be set up in special
1357 * ways (on i386 %edx is the address of a DT_FINI function, for
1358 * example. In addition, it may also specify (eg, PowerPC64 ELF)
1359 * that the e_entry field is the address of the function descriptor
1360 * for the startup routine, rather than the address of the startup
1361 * routine itself. This macro performs whatever initialization to
1362 * the regs structure is required as well as any relocations to the
1363 * function descriptor entries when executing dynamically links apps.
1364 */
1365 ELF_PLAT_INIT(regs, reloc_func_desc);
1366 #endif
1367
1368 finalize_exec(bprm);
1369 START_THREAD(elf_ex, regs, elf_entry, bprm->p);
1370 retval = 0;
1371 out:
1372 return retval;
1373
1374 /* error cleanup */
1375 out_free_dentry:
1376 kfree(interp_elf_ex);
1377 kfree(interp_elf_phdata);
1378 out_free_file:
1379 exe_file_allow_write_access(interpreter);
1380 if (interpreter)
1381 fput(interpreter);
1382 out_free_ph:
1383 kfree(elf_phdata);
1384 goto out;
1385 }
1386
1387 #ifdef CONFIG_USELIB
1388 /* This is really simpleminded and specialized - we are loading an
1389 a.out library that is given an ELF header. */
load_elf_library(struct file * file)1390 static int load_elf_library(struct file *file)
1391 {
1392 struct elf_phdr *elf_phdata;
1393 struct elf_phdr *eppnt;
1394 int retval, error, i, j;
1395 struct elfhdr elf_ex;
1396
1397 error = -ENOEXEC;
1398 retval = elf_read(file, &elf_ex, sizeof(elf_ex), 0);
1399 if (retval < 0)
1400 goto out;
1401
1402 if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
1403 goto out;
1404
1405 /* First of all, some simple consistency checks */
1406 if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
1407 !elf_check_arch(&elf_ex) || !file->f_op->mmap)
1408 goto out;
1409 if (elf_check_fdpic(&elf_ex))
1410 goto out;
1411
1412 /* Now read in all of the header information */
1413
1414 j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
1415 /* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */
1416
1417 error = -ENOMEM;
1418 elf_phdata = kmalloc(j, GFP_KERNEL);
1419 if (!elf_phdata)
1420 goto out;
1421
1422 eppnt = elf_phdata;
1423 error = -ENOEXEC;
1424 retval = elf_read(file, eppnt, j, elf_ex.e_phoff);
1425 if (retval < 0)
1426 goto out_free_ph;
1427
1428 for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
1429 if ((eppnt + i)->p_type == PT_LOAD)
1430 j++;
1431 if (j != 1)
1432 goto out_free_ph;
1433
1434 while (eppnt->p_type != PT_LOAD)
1435 eppnt++;
1436
1437 /* Now use mmap to map the library into memory. */
1438 error = elf_load(file, ELF_PAGESTART(eppnt->p_vaddr),
1439 eppnt,
1440 PROT_READ | PROT_WRITE | PROT_EXEC,
1441 MAP_FIXED_NOREPLACE | MAP_PRIVATE,
1442 0);
1443
1444 if (error != ELF_PAGESTART(eppnt->p_vaddr))
1445 goto out_free_ph;
1446
1447 error = 0;
1448
1449 out_free_ph:
1450 kfree(elf_phdata);
1451 out:
1452 return error;
1453 }
1454 #endif /* #ifdef CONFIG_USELIB */
1455
1456 #ifdef CONFIG_ELF_CORE
1457 /*
1458 * ELF core dumper
1459 *
1460 * Modelled on fs/exec.c:aout_core_dump()
1461 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1462 */
1463
1464 /* An ELF note in memory */
1465 struct memelfnote
1466 {
1467 const char *name;
1468 int type;
1469 unsigned int datasz;
1470 void *data;
1471 };
1472
notesize(struct memelfnote * en)1473 static int notesize(struct memelfnote *en)
1474 {
1475 int sz;
1476
1477 sz = sizeof(struct elf_note);
1478 sz += roundup(strlen(en->name) + 1, 4);
1479 sz += roundup(en->datasz, 4);
1480
1481 return sz;
1482 }
1483
writenote(struct memelfnote * men,struct coredump_params * cprm)1484 static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1485 {
1486 struct elf_note en;
1487 en.n_namesz = strlen(men->name) + 1;
1488 en.n_descsz = men->datasz;
1489 en.n_type = men->type;
1490
1491 return dump_emit(cprm, &en, sizeof(en)) &&
1492 dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
1493 dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
1494 }
1495
fill_elf_header(struct elfhdr * elf,int segs,u16 machine,u32 flags)1496 static void fill_elf_header(struct elfhdr *elf, int segs,
1497 u16 machine, u32 flags)
1498 {
1499 memset(elf, 0, sizeof(*elf));
1500
1501 memcpy(elf->e_ident, ELFMAG, SELFMAG);
1502 elf->e_ident[EI_CLASS] = ELF_CLASS;
1503 elf->e_ident[EI_DATA] = ELF_DATA;
1504 elf->e_ident[EI_VERSION] = EV_CURRENT;
1505 elf->e_ident[EI_OSABI] = ELF_OSABI;
1506
1507 elf->e_type = ET_CORE;
1508 elf->e_machine = machine;
1509 elf->e_version = EV_CURRENT;
1510 elf->e_phoff = sizeof(struct elfhdr);
1511 elf->e_flags = flags;
1512 elf->e_ehsize = sizeof(struct elfhdr);
1513 elf->e_phentsize = sizeof(struct elf_phdr);
1514 elf->e_phnum = segs;
1515 }
1516
fill_elf_note_phdr(struct elf_phdr * phdr,int sz,loff_t offset)1517 static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1518 {
1519 phdr->p_type = PT_NOTE;
1520 phdr->p_offset = offset;
1521 phdr->p_vaddr = 0;
1522 phdr->p_paddr = 0;
1523 phdr->p_filesz = sz;
1524 phdr->p_memsz = 0;
1525 phdr->p_flags = 0;
1526 phdr->p_align = 4;
1527 }
1528
fill_note(struct memelfnote * note,const char * name,int type,unsigned int sz,void * data)1529 static void fill_note(struct memelfnote *note, const char *name, int type,
1530 unsigned int sz, void *data)
1531 {
1532 note->name = name;
1533 note->type = type;
1534 note->datasz = sz;
1535 note->data = data;
1536 }
1537
1538 /*
1539 * fill up all the fields in prstatus from the given task struct, except
1540 * registers which need to be filled up separately.
1541 */
fill_prstatus(struct elf_prstatus_common * prstatus,struct task_struct * p,long signr)1542 static void fill_prstatus(struct elf_prstatus_common *prstatus,
1543 struct task_struct *p, long signr)
1544 {
1545 prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1546 prstatus->pr_sigpend = p->pending.signal.sig[0];
1547 prstatus->pr_sighold = p->blocked.sig[0];
1548 rcu_read_lock();
1549 prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1550 rcu_read_unlock();
1551 prstatus->pr_pid = task_pid_vnr(p);
1552 prstatus->pr_pgrp = task_pgrp_vnr(p);
1553 prstatus->pr_sid = task_session_vnr(p);
1554 if (thread_group_leader(p)) {
1555 struct task_cputime cputime;
1556
1557 /*
1558 * This is the record for the group leader. It shows the
1559 * group-wide total, not its individual thread total.
1560 */
1561 thread_group_cputime(p, &cputime);
1562 prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
1563 prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
1564 } else {
1565 u64 utime, stime;
1566
1567 task_cputime(p, &utime, &stime);
1568 prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
1569 prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
1570 }
1571
1572 prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
1573 prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
1574 }
1575
fill_psinfo(struct elf_prpsinfo * psinfo,struct task_struct * p,struct mm_struct * mm)1576 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1577 struct mm_struct *mm)
1578 {
1579 const struct cred *cred;
1580 unsigned int i, len;
1581 unsigned int state;
1582
1583 /* first copy the parameters from user space */
1584 memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1585
1586 len = mm->arg_end - mm->arg_start;
1587 if (len >= ELF_PRARGSZ)
1588 len = ELF_PRARGSZ-1;
1589 if (copy_from_user(&psinfo->pr_psargs,
1590 (const char __user *)mm->arg_start, len))
1591 return -EFAULT;
1592 for(i = 0; i < len; i++)
1593 if (psinfo->pr_psargs[i] == 0)
1594 psinfo->pr_psargs[i] = ' ';
1595 psinfo->pr_psargs[len] = 0;
1596
1597 rcu_read_lock();
1598 psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1599 rcu_read_unlock();
1600 psinfo->pr_pid = task_pid_vnr(p);
1601 psinfo->pr_pgrp = task_pgrp_vnr(p);
1602 psinfo->pr_sid = task_session_vnr(p);
1603
1604 state = READ_ONCE(p->__state);
1605 i = state ? ffz(~state) + 1 : 0;
1606 psinfo->pr_state = i;
1607 psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1608 psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1609 psinfo->pr_nice = task_nice(p);
1610 psinfo->pr_flag = p->flags;
1611 rcu_read_lock();
1612 cred = __task_cred(p);
1613 SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
1614 SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1615 rcu_read_unlock();
1616 get_task_comm(psinfo->pr_fname, p);
1617
1618 return 0;
1619 }
1620
fill_auxv_note(struct memelfnote * note,struct mm_struct * mm)1621 static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
1622 {
1623 elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
1624 int i = 0;
1625 do
1626 i += 2;
1627 while (auxv[i - 2] != AT_NULL);
1628 fill_note(note, NN_AUXV, NT_AUXV, i * sizeof(elf_addr_t), auxv);
1629 }
1630
fill_siginfo_note(struct memelfnote * note,user_siginfo_t * csigdata,const kernel_siginfo_t * siginfo)1631 static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
1632 const kernel_siginfo_t *siginfo)
1633 {
1634 copy_siginfo_to_external(csigdata, siginfo);
1635 fill_note(note, NN_SIGINFO, NT_SIGINFO, sizeof(*csigdata), csigdata);
1636 }
1637
1638 /*
1639 * Format of NT_FILE note:
1640 *
1641 * long count -- how many files are mapped
1642 * long page_size -- units for file_ofs
1643 * array of [COUNT] elements of
1644 * long start
1645 * long end
1646 * long file_ofs
1647 * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL...
1648 */
fill_files_note(struct memelfnote * note,struct coredump_params * cprm)1649 static int fill_files_note(struct memelfnote *note, struct coredump_params *cprm)
1650 {
1651 unsigned count, size, names_ofs, remaining, n;
1652 user_long_t *data;
1653 user_long_t *start_end_ofs;
1654 char *name_base, *name_curpos;
1655 int i;
1656
1657 /* *Estimated* file count and total data size needed */
1658 count = cprm->vma_count;
1659 if (count > UINT_MAX / 64)
1660 return -EINVAL;
1661 size = count * 64;
1662
1663 names_ofs = (2 + 3 * count) * sizeof(data[0]);
1664 alloc:
1665 /* paranoia check */
1666 if (size >= core_file_note_size_limit) {
1667 pr_warn_once("coredump Note size too large: %u (does kernel.core_file_note_size_limit sysctl need adjustment?\n",
1668 size);
1669 return -EINVAL;
1670 }
1671 size = round_up(size, PAGE_SIZE);
1672 /*
1673 * "size" can be 0 here legitimately.
1674 * Let it ENOMEM and omit NT_FILE section which will be empty anyway.
1675 */
1676 data = kvmalloc(size, GFP_KERNEL);
1677 if (ZERO_OR_NULL_PTR(data))
1678 return -ENOMEM;
1679
1680 start_end_ofs = data + 2;
1681 name_base = name_curpos = ((char *)data) + names_ofs;
1682 remaining = size - names_ofs;
1683 count = 0;
1684 for (i = 0; i < cprm->vma_count; i++) {
1685 struct core_vma_metadata *m = &cprm->vma_meta[i];
1686 struct file *file;
1687 const char *filename;
1688
1689 file = m->file;
1690 if (!file)
1691 continue;
1692 filename = file_path(file, name_curpos, remaining);
1693 if (IS_ERR(filename)) {
1694 if (PTR_ERR(filename) == -ENAMETOOLONG) {
1695 kvfree(data);
1696 size = size * 5 / 4;
1697 goto alloc;
1698 }
1699 continue;
1700 }
1701
1702 /* file_path() fills at the end, move name down */
1703 /* n = strlen(filename) + 1: */
1704 n = (name_curpos + remaining) - filename;
1705 remaining = filename - name_curpos;
1706 memmove(name_curpos, filename, n);
1707 name_curpos += n;
1708
1709 *start_end_ofs++ = m->start;
1710 *start_end_ofs++ = m->end;
1711 *start_end_ofs++ = m->pgoff;
1712 count++;
1713 }
1714
1715 /* Now we know exact count of files, can store it */
1716 data[0] = count;
1717 data[1] = PAGE_SIZE;
1718 /*
1719 * Count usually is less than mm->map_count,
1720 * we need to move filenames down.
1721 */
1722 n = cprm->vma_count - count;
1723 if (n != 0) {
1724 unsigned shift_bytes = n * 3 * sizeof(data[0]);
1725 memmove(name_base - shift_bytes, name_base,
1726 name_curpos - name_base);
1727 name_curpos -= shift_bytes;
1728 }
1729
1730 size = name_curpos - (char *)data;
1731 fill_note(note, NN_FILE, NT_FILE, size, data);
1732 return 0;
1733 }
1734
1735 #include <linux/regset.h>
1736
1737 struct elf_thread_core_info {
1738 struct elf_thread_core_info *next;
1739 struct task_struct *task;
1740 struct elf_prstatus prstatus;
1741 struct memelfnote notes[];
1742 };
1743
1744 struct elf_note_info {
1745 struct elf_thread_core_info *thread;
1746 struct memelfnote psinfo;
1747 struct memelfnote signote;
1748 struct memelfnote auxv;
1749 struct memelfnote files;
1750 user_siginfo_t csigdata;
1751 size_t size;
1752 int thread_notes;
1753 };
1754
1755 #ifdef CORE_DUMP_USE_REGSET
1756 /*
1757 * When a regset has a writeback hook, we call it on each thread before
1758 * dumping user memory. On register window machines, this makes sure the
1759 * user memory backing the register data is up to date before we read it.
1760 */
do_thread_regset_writeback(struct task_struct * task,const struct user_regset * regset)1761 static void do_thread_regset_writeback(struct task_struct *task,
1762 const struct user_regset *regset)
1763 {
1764 if (regset->writeback)
1765 regset->writeback(task, regset, 1);
1766 }
1767
1768 #ifndef PRSTATUS_SIZE
1769 #define PRSTATUS_SIZE sizeof(struct elf_prstatus)
1770 #endif
1771
1772 #ifndef SET_PR_FPVALID
1773 #define SET_PR_FPVALID(S) ((S)->pr_fpvalid = 1)
1774 #endif
1775
fill_thread_core_info(struct elf_thread_core_info * t,const struct user_regset_view * view,long signr,struct elf_note_info * info)1776 static int fill_thread_core_info(struct elf_thread_core_info *t,
1777 const struct user_regset_view *view,
1778 long signr, struct elf_note_info *info)
1779 {
1780 unsigned int note_iter, view_iter;
1781
1782 /*
1783 * NT_PRSTATUS is the one special case, because the regset data
1784 * goes into the pr_reg field inside the note contents, rather
1785 * than being the whole note contents. We fill the regset in here.
1786 * We assume that regset 0 is NT_PRSTATUS.
1787 */
1788 fill_prstatus(&t->prstatus.common, t->task, signr);
1789 regset_get(t->task, &view->regsets[0],
1790 sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
1791
1792 fill_note(&t->notes[0], NN_PRSTATUS, NT_PRSTATUS,
1793 PRSTATUS_SIZE, &t->prstatus);
1794 info->size += notesize(&t->notes[0]);
1795
1796 do_thread_regset_writeback(t->task, &view->regsets[0]);
1797
1798 /*
1799 * Each other regset might generate a note too. For each regset
1800 * that has no core_note_type or is inactive, skip it.
1801 */
1802 note_iter = 1;
1803 for (view_iter = 1; view_iter < view->n; ++view_iter) {
1804 const struct user_regset *regset = &view->regsets[view_iter];
1805 int note_type = regset->core_note_type;
1806 bool is_fpreg = note_type == NT_PRFPREG;
1807 void *data;
1808 int ret;
1809
1810 do_thread_regset_writeback(t->task, regset);
1811 if (!note_type) // not for coredumps
1812 continue;
1813 if (regset->active && regset->active(t->task, regset) <= 0)
1814 continue;
1815
1816 ret = regset_get_alloc(t->task, regset, ~0U, &data);
1817 if (ret < 0)
1818 continue;
1819
1820 if (WARN_ON_ONCE(note_iter >= info->thread_notes))
1821 break;
1822
1823 if (is_fpreg)
1824 SET_PR_FPVALID(&t->prstatus);
1825
1826 fill_note(&t->notes[note_iter], is_fpreg ? NN_PRFPREG : "LINUX",
1827 note_type, ret, data);
1828
1829 info->size += notesize(&t->notes[note_iter]);
1830 note_iter++;
1831 }
1832
1833 return 1;
1834 }
1835 #else
fill_thread_core_info(struct elf_thread_core_info * t,const struct user_regset_view * view,long signr,struct elf_note_info * info)1836 static int fill_thread_core_info(struct elf_thread_core_info *t,
1837 const struct user_regset_view *view,
1838 long signr, struct elf_note_info *info)
1839 {
1840 struct task_struct *p = t->task;
1841 elf_fpregset_t *fpu;
1842
1843 fill_prstatus(&t->prstatus.common, p, signr);
1844 elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1845
1846 fill_note(&t->notes[0], NN_PRSTATUS, NT_PRSTATUS, sizeof(t->prstatus),
1847 &(t->prstatus));
1848 info->size += notesize(&t->notes[0]);
1849
1850 fpu = kzalloc(sizeof(elf_fpregset_t), GFP_KERNEL);
1851 if (!fpu || !elf_core_copy_task_fpregs(p, fpu)) {
1852 kfree(fpu);
1853 return 1;
1854 }
1855
1856 t->prstatus.pr_fpvalid = 1;
1857 fill_note(&t->notes[1], NN_PRFPREG, NT_PRFPREG, sizeof(*fpu), fpu);
1858 info->size += notesize(&t->notes[1]);
1859
1860 return 1;
1861 }
1862 #endif
1863
fill_note_info(struct elfhdr * elf,int phdrs,struct elf_note_info * info,struct coredump_params * cprm)1864 static int fill_note_info(struct elfhdr *elf, int phdrs,
1865 struct elf_note_info *info,
1866 struct coredump_params *cprm)
1867 {
1868 struct task_struct *dump_task = current;
1869 const struct user_regset_view *view;
1870 struct elf_thread_core_info *t;
1871 struct elf_prpsinfo *psinfo;
1872 struct core_thread *ct;
1873
1874 psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1875 if (!psinfo)
1876 return 0;
1877 fill_note(&info->psinfo, NN_PRPSINFO, NT_PRPSINFO, sizeof(*psinfo), psinfo);
1878
1879 #ifdef CORE_DUMP_USE_REGSET
1880 view = task_user_regset_view(dump_task);
1881
1882 /*
1883 * Figure out how many notes we're going to need for each thread.
1884 */
1885 info->thread_notes = 0;
1886 for (int i = 0; i < view->n; ++i)
1887 if (view->regsets[i].core_note_type != 0)
1888 ++info->thread_notes;
1889
1890 /*
1891 * Sanity check. We rely on regset 0 being in NT_PRSTATUS,
1892 * since it is our one special case.
1893 */
1894 if (unlikely(info->thread_notes == 0) ||
1895 unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
1896 WARN_ON(1);
1897 return 0;
1898 }
1899
1900 /*
1901 * Initialize the ELF file header.
1902 */
1903 fill_elf_header(elf, phdrs,
1904 view->e_machine, view->e_flags);
1905 #else
1906 view = NULL;
1907 info->thread_notes = 2;
1908 fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS);
1909 #endif
1910
1911 /*
1912 * Allocate a structure for each thread.
1913 */
1914 info->thread = kzalloc(offsetof(struct elf_thread_core_info,
1915 notes[info->thread_notes]),
1916 GFP_KERNEL);
1917 if (unlikely(!info->thread))
1918 return 0;
1919
1920 info->thread->task = dump_task;
1921 for (ct = dump_task->signal->core_state->dumper.next; ct; ct = ct->next) {
1922 t = kzalloc(offsetof(struct elf_thread_core_info,
1923 notes[info->thread_notes]),
1924 GFP_KERNEL);
1925 if (unlikely(!t))
1926 return 0;
1927
1928 t->task = ct->task;
1929 t->next = info->thread->next;
1930 info->thread->next = t;
1931 }
1932
1933 /*
1934 * Now fill in each thread's information.
1935 */
1936 for (t = info->thread; t != NULL; t = t->next)
1937 if (!fill_thread_core_info(t, view, cprm->siginfo->si_signo, info))
1938 return 0;
1939
1940 /*
1941 * Fill in the two process-wide notes.
1942 */
1943 fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
1944 info->size += notesize(&info->psinfo);
1945
1946 fill_siginfo_note(&info->signote, &info->csigdata, cprm->siginfo);
1947 info->size += notesize(&info->signote);
1948
1949 fill_auxv_note(&info->auxv, current->mm);
1950 info->size += notesize(&info->auxv);
1951
1952 if (fill_files_note(&info->files, cprm) == 0)
1953 info->size += notesize(&info->files);
1954
1955 return 1;
1956 }
1957
1958 /*
1959 * Write all the notes for each thread. When writing the first thread, the
1960 * process-wide notes are interleaved after the first thread-specific note.
1961 */
write_note_info(struct elf_note_info * info,struct coredump_params * cprm)1962 static int write_note_info(struct elf_note_info *info,
1963 struct coredump_params *cprm)
1964 {
1965 bool first = true;
1966 struct elf_thread_core_info *t = info->thread;
1967
1968 do {
1969 int i;
1970
1971 if (!writenote(&t->notes[0], cprm))
1972 return 0;
1973
1974 if (first && !writenote(&info->psinfo, cprm))
1975 return 0;
1976 if (first && !writenote(&info->signote, cprm))
1977 return 0;
1978 if (first && !writenote(&info->auxv, cprm))
1979 return 0;
1980 if (first && info->files.data &&
1981 !writenote(&info->files, cprm))
1982 return 0;
1983
1984 for (i = 1; i < info->thread_notes; ++i)
1985 if (t->notes[i].data &&
1986 !writenote(&t->notes[i], cprm))
1987 return 0;
1988
1989 first = false;
1990 t = t->next;
1991 } while (t);
1992
1993 return 1;
1994 }
1995
free_note_info(struct elf_note_info * info)1996 static void free_note_info(struct elf_note_info *info)
1997 {
1998 struct elf_thread_core_info *threads = info->thread;
1999 while (threads) {
2000 unsigned int i;
2001 struct elf_thread_core_info *t = threads;
2002 threads = t->next;
2003 WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
2004 for (i = 1; i < info->thread_notes; ++i)
2005 kvfree(t->notes[i].data);
2006 kfree(t);
2007 }
2008 kfree(info->psinfo.data);
2009 kvfree(info->files.data);
2010 }
2011
fill_extnum_info(struct elfhdr * elf,struct elf_shdr * shdr4extnum,elf_addr_t e_shoff,int segs)2012 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
2013 elf_addr_t e_shoff, int segs)
2014 {
2015 elf->e_shoff = e_shoff;
2016 elf->e_shentsize = sizeof(*shdr4extnum);
2017 elf->e_shnum = 1;
2018 elf->e_shstrndx = SHN_UNDEF;
2019
2020 memset(shdr4extnum, 0, sizeof(*shdr4extnum));
2021
2022 shdr4extnum->sh_type = SHT_NULL;
2023 shdr4extnum->sh_size = elf->e_shnum;
2024 shdr4extnum->sh_link = elf->e_shstrndx;
2025 shdr4extnum->sh_info = segs;
2026 }
2027
2028 /*
2029 * Actual dumper
2030 *
2031 * This is a two-pass process; first we find the offsets of the bits,
2032 * and then they are actually written out. If we run out of core limit
2033 * we just truncate.
2034 */
elf_core_dump(struct coredump_params * cprm)2035 static int elf_core_dump(struct coredump_params *cprm)
2036 {
2037 int has_dumped = 0;
2038 int segs, i;
2039 struct elfhdr elf;
2040 loff_t offset = 0, dataoff;
2041 struct elf_note_info info = { };
2042 struct elf_phdr *phdr4note = NULL;
2043 struct elf_shdr *shdr4extnum = NULL;
2044 Elf_Half e_phnum;
2045 elf_addr_t e_shoff;
2046
2047 /*
2048 * The number of segs are recored into ELF header as 16bit value.
2049 * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
2050 */
2051 segs = cprm->vma_count + elf_core_extra_phdrs(cprm);
2052
2053 /* for notes section */
2054 segs++;
2055
2056 /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
2057 * this, kernel supports extended numbering. Have a look at
2058 * include/linux/elf.h for further information. */
2059 e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
2060
2061 /*
2062 * Collect all the non-memory information about the process for the
2063 * notes. This also sets up the file header.
2064 */
2065 if (!fill_note_info(&elf, e_phnum, &info, cprm))
2066 goto end_coredump;
2067
2068 has_dumped = 1;
2069
2070 offset += sizeof(elf); /* ELF header */
2071 offset += segs * sizeof(struct elf_phdr); /* Program headers */
2072
2073 /* Write notes phdr entry */
2074 {
2075 size_t sz = info.size;
2076
2077 /* For cell spufs and x86 xstate */
2078 sz += elf_coredump_extra_notes_size();
2079
2080 phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
2081 if (!phdr4note)
2082 goto end_coredump;
2083
2084 fill_elf_note_phdr(phdr4note, sz, offset);
2085 offset += sz;
2086 }
2087
2088 dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
2089
2090 offset += cprm->vma_data_size;
2091 offset += elf_core_extra_data_size(cprm);
2092 e_shoff = offset;
2093
2094 if (e_phnum == PN_XNUM) {
2095 shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
2096 if (!shdr4extnum)
2097 goto end_coredump;
2098 fill_extnum_info(&elf, shdr4extnum, e_shoff, segs);
2099 }
2100
2101 offset = dataoff;
2102
2103 if (!dump_emit(cprm, &elf, sizeof(elf)))
2104 goto end_coredump;
2105
2106 if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
2107 goto end_coredump;
2108
2109 /* Write program headers for segments dump */
2110 for (i = 0; i < cprm->vma_count; i++) {
2111 struct core_vma_metadata *meta = cprm->vma_meta + i;
2112 struct elf_phdr phdr;
2113
2114 phdr.p_type = PT_LOAD;
2115 phdr.p_offset = offset;
2116 phdr.p_vaddr = meta->start;
2117 phdr.p_paddr = 0;
2118 phdr.p_filesz = meta->dump_size;
2119 phdr.p_memsz = meta->end - meta->start;
2120 offset += phdr.p_filesz;
2121 phdr.p_flags = 0;
2122 if (meta->flags & VM_READ)
2123 phdr.p_flags |= PF_R;
2124 if (meta->flags & VM_WRITE)
2125 phdr.p_flags |= PF_W;
2126 if (meta->flags & VM_EXEC)
2127 phdr.p_flags |= PF_X;
2128 phdr.p_align = ELF_EXEC_PAGESIZE;
2129
2130 if (!dump_emit(cprm, &phdr, sizeof(phdr)))
2131 goto end_coredump;
2132 }
2133
2134 if (!elf_core_write_extra_phdrs(cprm, offset))
2135 goto end_coredump;
2136
2137 /* write out the notes section */
2138 if (!write_note_info(&info, cprm))
2139 goto end_coredump;
2140
2141 /* For cell spufs and x86 xstate */
2142 if (elf_coredump_extra_notes_write(cprm))
2143 goto end_coredump;
2144
2145 /* Align to page */
2146 dump_skip_to(cprm, dataoff);
2147
2148 for (i = 0; i < cprm->vma_count; i++) {
2149 struct core_vma_metadata *meta = cprm->vma_meta + i;
2150
2151 if (!dump_user_range(cprm, meta->start, meta->dump_size))
2152 goto end_coredump;
2153 }
2154
2155 if (!elf_core_write_extra_data(cprm))
2156 goto end_coredump;
2157
2158 if (e_phnum == PN_XNUM) {
2159 if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
2160 goto end_coredump;
2161 }
2162
2163 end_coredump:
2164 free_note_info(&info);
2165 kfree(shdr4extnum);
2166 kfree(phdr4note);
2167 return has_dumped;
2168 }
2169
2170 #endif /* CONFIG_ELF_CORE */
2171
init_elf_binfmt(void)2172 static int __init init_elf_binfmt(void)
2173 {
2174 register_binfmt(&elf_format);
2175 return 0;
2176 }
2177
exit_elf_binfmt(void)2178 static void __exit exit_elf_binfmt(void)
2179 {
2180 /* Remove the COFF and ELF loaders. */
2181 unregister_binfmt(&elf_format);
2182 }
2183
2184 core_initcall(init_elf_binfmt);
2185 module_exit(exit_elf_binfmt);
2186
2187 #ifdef CONFIG_BINFMT_ELF_KUNIT_TEST
2188 #include "tests/binfmt_elf_kunit.c"
2189 #endif
2190