1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* Module internals
3 *
4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 * Copyright (C) 2023 Luis Chamberlain <mcgrof@kernel.org>
7 */
8
9 #include <linux/elf.h>
10 #include <linux/compiler.h>
11 #include <linux/module.h>
12 #include <linux/mutex.h>
13 #include <linux/rculist.h>
14 #include <linux/rcupdate.h>
15 #include <linux/mm.h>
16
17 #ifndef ARCH_SHF_SMALL
18 #define ARCH_SHF_SMALL 0
19 #endif
20
21 /*
22 * Use highest 4 bits of sh_entsize to store the mod_mem_type of this
23 * section. This leaves 28 bits for offset on 32-bit systems, which is
24 * about 256 MiB (WARN_ON_ONCE if we exceed that).
25 */
26
27 #define SH_ENTSIZE_TYPE_BITS 4
28 #define SH_ENTSIZE_TYPE_SHIFT (BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS)
29 #define SH_ENTSIZE_TYPE_MASK ((1UL << SH_ENTSIZE_TYPE_BITS) - 1)
30 #define SH_ENTSIZE_OFFSET_MASK ((1UL << (BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS)) - 1)
31
32 /* Maximum number of characters written by module_flags() */
33 #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
34
35 struct kernel_symbol {
36 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
37 int value_offset;
38 int name_offset;
39 int namespace_offset;
40 #else
41 unsigned long value;
42 const char *name;
43 const char *namespace;
44 #endif
45 };
46
47 extern struct mutex module_mutex;
48 extern struct list_head modules;
49
50 extern const struct module_attribute *const modinfo_attrs[];
51 extern const size_t modinfo_attrs_count;
52
53 /* Provided by the linker */
54 extern const struct kernel_symbol __start___ksymtab[];
55 extern const struct kernel_symbol __stop___ksymtab[];
56 extern const u32 __start___kcrctab[];
57 extern const u8 __start___kflagstab[];
58
59 #define KMOD_PATH_LEN 256
60 extern char modprobe_path[];
61
62 struct load_info {
63 const char *name;
64 /* pointer to module in temporary copy, freed at end of load_module() */
65 struct module *mod;
66 Elf_Ehdr *hdr;
67 unsigned long len;
68 Elf_Shdr *sechdrs;
69 char *secstrings, *strtab;
70 unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs;
71 bool sig_ok;
72 #ifdef CONFIG_KALLSYMS
73 unsigned long mod_kallsyms_init_off;
74 #endif
75 #ifdef CONFIG_MODULE_DECOMPRESS
76 #ifdef CONFIG_MODULE_STATS
77 unsigned long compressed_len;
78 #endif
79 struct page **pages;
80 unsigned int max_pages;
81 unsigned int used_pages;
82 #endif
83 struct {
84 unsigned int sym;
85 unsigned int str;
86 unsigned int mod;
87 unsigned int vers;
88 unsigned int info;
89 unsigned int pcpu;
90 unsigned int vers_ext_crc;
91 unsigned int vers_ext_name;
92 } index;
93 };
94
95 enum mod_license {
96 NOT_GPL_ONLY,
97 GPL_ONLY,
98 };
99
100 struct find_symbol_arg {
101 /* Input */
102 const char *name;
103 bool gplok;
104 bool warn;
105
106 /* Output */
107 struct module *owner;
108 const u32 *crc;
109 const struct kernel_symbol *sym;
110 enum mod_license license;
111 };
112
113 /* modules using other modules */
114 struct module_use {
115 struct list_head source_list;
116 struct list_head target_list;
117 struct module *source, *target;
118 };
119
120 int mod_verify_sig(const void *mod, struct load_info *info);
121 int try_to_force_load(struct module *mod, const char *reason);
122 bool find_symbol(struct find_symbol_arg *fsa);
123 struct module *find_module_all(const char *name, size_t len, bool even_unformed);
124 int cmp_name(const void *name, const void *sym);
125 long module_get_offset_and_type(struct module *mod, enum mod_mem_type type,
126 Elf_Shdr *sechdr, unsigned int section);
127 char *module_flags(struct module *mod, char *buf, bool show_state);
128 size_t module_flags_taint(unsigned long taints, char *buf);
129
130 char *module_next_tag_pair(char *string, unsigned long *secsize);
131
132 #define for_each_modinfo_entry(entry, info, name) \
133 for (entry = get_modinfo(info, name); entry; entry = get_next_modinfo(info, name, entry))
134
kernel_symbol_value(const struct kernel_symbol * sym)135 static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym)
136 {
137 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
138 return (unsigned long)offset_to_ptr(&sym->value_offset);
139 #else
140 return sym->value;
141 #endif
142 }
143
144 #ifdef CONFIG_LIVEPATCH
145 int copy_module_elf(struct module *mod, struct load_info *info);
146 void free_module_elf(struct module *mod);
147 #else /* !CONFIG_LIVEPATCH */
copy_module_elf(struct module * mod,struct load_info * info)148 static inline int copy_module_elf(struct module *mod, struct load_info *info)
149 {
150 return 0;
151 }
152
free_module_elf(struct module * mod)153 static inline void free_module_elf(struct module *mod) { }
154 #endif /* CONFIG_LIVEPATCH */
155
set_livepatch_module(struct module * mod)156 static inline bool set_livepatch_module(struct module *mod)
157 {
158 #ifdef CONFIG_LIVEPATCH
159 mod->klp = true;
160 return true;
161 #else
162 return false;
163 #endif
164 }
165
166 /**
167 * enum fail_dup_mod_reason - state at which a duplicate module was detected
168 *
169 * @FAIL_DUP_MOD_BECOMING: the module is read properly, passes all checks but
170 * we've determined that another module with the same name is already loaded
171 * or being processed on our &modules list. This happens on early_mod_check()
172 * right before layout_and_allocate(). The kernel would have already
173 * vmalloc()'d space for the entire module through finit_module(). If
174 * decompression was used two vmap() spaces were used. These failures can
175 * happen when userspace has not seen the module present on the kernel and
176 * tries to load the module multiple times at same time.
177 * @FAIL_DUP_MOD_LOAD: the module has been read properly, passes all validation
178 * checks and the kernel determines that the module was unique and because
179 * of this allocated yet another private kernel copy of the module space in
180 * layout_and_allocate() but after this determined in add_unformed_module()
181 * that another module with the same name is already loaded or being processed.
182 * These failures should be mitigated as much as possible and are indicative
183 * of really fast races in loading modules. Without module decompression
184 * they waste twice as much vmap space. With module decompression three
185 * times the module's size vmap space is wasted.
186 */
187 enum fail_dup_mod_reason {
188 FAIL_DUP_MOD_BECOMING = 0,
189 FAIL_DUP_MOD_LOAD,
190 };
191
192 #ifdef CONFIG_MODULE_DEBUGFS
193 extern struct dentry *mod_debugfs_root;
194 #endif
195
196 #ifdef CONFIG_MODULE_STATS
197
198 #define mod_stat_add_long(count, var) atomic_long_add(count, var)
199 #define mod_stat_inc(name) atomic_inc(name)
200
201 extern atomic_long_t total_mod_size;
202 extern atomic_long_t total_text_size;
203 extern atomic_long_t invalid_kread_bytes;
204 extern atomic_long_t invalid_decompress_bytes;
205
206 extern atomic_t modcount;
207 extern atomic_t failed_kreads;
208 extern atomic_t failed_decompress;
209 struct mod_fail_load {
210 struct list_head list;
211 char name[MODULE_NAME_LEN];
212 atomic_long_t count;
213 unsigned long dup_fail_mask;
214 };
215
216 int try_add_failed_module(const char *name, enum fail_dup_mod_reason reason);
217 void mod_stat_bump_invalid(struct load_info *info, int flags);
218 void mod_stat_bump_becoming(struct load_info *info, int flags);
219
220 #else
221
222 #define mod_stat_add_long(name, var)
223 #define mod_stat_inc(name)
224
try_add_failed_module(const char * name,enum fail_dup_mod_reason reason)225 static inline int try_add_failed_module(const char *name,
226 enum fail_dup_mod_reason reason)
227 {
228 return 0;
229 }
230
mod_stat_bump_invalid(struct load_info * info,int flags)231 static inline void mod_stat_bump_invalid(struct load_info *info, int flags)
232 {
233 }
234
mod_stat_bump_becoming(struct load_info * info,int flags)235 static inline void mod_stat_bump_becoming(struct load_info *info, int flags)
236 {
237 }
238
239 #endif /* CONFIG_MODULE_STATS */
240
241 #ifdef CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS
242 bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret);
243 void kmod_dup_request_announce(char *module_name, int ret);
244 #else
kmod_dup_request_exists_wait(char * module_name,bool wait,int * dup_ret)245 static inline bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret)
246 {
247 return false;
248 }
249
kmod_dup_request_announce(char * module_name,int ret)250 static inline void kmod_dup_request_announce(char *module_name, int ret)
251 {
252 }
253 #endif
254
255 #ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING
256 struct mod_unload_taint {
257 struct list_head list;
258 char name[MODULE_NAME_LEN];
259 unsigned long taints;
260 u64 count;
261 };
262
263 int try_add_tainted_module(struct module *mod);
264 void print_unloaded_tainted_modules(void);
265 #else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */
try_add_tainted_module(struct module * mod)266 static inline int try_add_tainted_module(struct module *mod)
267 {
268 return 0;
269 }
270
print_unloaded_tainted_modules(void)271 static inline void print_unloaded_tainted_modules(void)
272 {
273 }
274 #endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */
275
276 #ifdef CONFIG_MODULE_DECOMPRESS
277 int module_decompress(struct load_info *info, const void *buf, size_t size);
278 void module_decompress_cleanup(struct load_info *info);
279 #else
module_decompress(struct load_info * info,const void * buf,size_t size)280 static inline int module_decompress(struct load_info *info,
281 const void *buf, size_t size)
282 {
283 return -EOPNOTSUPP;
284 }
285
module_decompress_cleanup(struct load_info * info)286 static inline void module_decompress_cleanup(struct load_info *info)
287 {
288 }
289 #endif
290
291 struct mod_tree_root {
292 #ifdef CONFIG_MODULES_TREE_LOOKUP
293 struct latch_tree_root root;
294 #endif
295 unsigned long addr_min;
296 unsigned long addr_max;
297 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
298 unsigned long data_addr_min;
299 unsigned long data_addr_max;
300 #endif
301 };
302
303 extern struct mod_tree_root mod_tree;
304
305 #ifdef CONFIG_MODULES_TREE_LOOKUP
306 void mod_tree_insert(struct module *mod);
307 void mod_tree_remove_init(struct module *mod);
308 void mod_tree_remove(struct module *mod);
309 struct module *mod_find(unsigned long addr, struct mod_tree_root *tree);
310 #else /* !CONFIG_MODULES_TREE_LOOKUP */
311
mod_tree_insert(struct module * mod)312 static inline void mod_tree_insert(struct module *mod) { }
mod_tree_remove_init(struct module * mod)313 static inline void mod_tree_remove_init(struct module *mod) { }
mod_tree_remove(struct module * mod)314 static inline void mod_tree_remove(struct module *mod) { }
mod_find(unsigned long addr,struct mod_tree_root * tree)315 static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree)
316 {
317 struct module *mod;
318
319 list_for_each_entry_rcu(mod, &modules, list,
320 lockdep_is_held(&module_mutex)) {
321 if (within_module(addr, mod))
322 return mod;
323 }
324
325 return NULL;
326 }
327 #endif /* CONFIG_MODULES_TREE_LOOKUP */
328
329 int module_enable_rodata_ro(const struct module *mod);
330 int module_enable_rodata_ro_after_init(const struct module *mod);
331 int module_enable_data_nx(const struct module *mod);
332 int module_enable_text_rox(const struct module *mod);
333 int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
334 const char *secstrings,
335 const struct module *mod);
336 void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
337 const char *secstrings);
338
339 #ifdef CONFIG_MODULE_SIG
340 int module_sig_check(struct load_info *info, int flags);
341 #else /* !CONFIG_MODULE_SIG */
module_sig_check(struct load_info * info,int flags)342 static inline int module_sig_check(struct load_info *info, int flags)
343 {
344 return 0;
345 }
346 #endif /* !CONFIG_MODULE_SIG */
347
348 #ifdef CONFIG_DEBUG_KMEMLEAK
349 void kmemleak_load_module(const struct module *mod, const struct load_info *info);
350 #else /* !CONFIG_DEBUG_KMEMLEAK */
kmemleak_load_module(const struct module * mod,const struct load_info * info)351 static inline void kmemleak_load_module(const struct module *mod,
352 const struct load_info *info) { }
353 #endif /* CONFIG_DEBUG_KMEMLEAK */
354
355 #ifdef CONFIG_KALLSYMS
356 void init_build_id(struct module *mod, const struct load_info *info);
357 void layout_symtab(struct module *mod, struct load_info *info);
358 void add_kallsyms(struct module *mod, const struct load_info *info);
359
sect_empty(const Elf_Shdr * sect)360 static inline bool sect_empty(const Elf_Shdr *sect)
361 {
362 return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
363 }
364 #else /* !CONFIG_KALLSYMS */
init_build_id(struct module * mod,const struct load_info * info)365 static inline void init_build_id(struct module *mod, const struct load_info *info) { }
layout_symtab(struct module * mod,struct load_info * info)366 static inline void layout_symtab(struct module *mod, struct load_info *info) { }
add_kallsyms(struct module * mod,const struct load_info * info)367 static inline void add_kallsyms(struct module *mod, const struct load_info *info) { }
368 #endif /* CONFIG_KALLSYMS */
369
370 #ifdef CONFIG_SYSFS
371 int mod_sysfs_setup(struct module *mod, const struct load_info *info,
372 struct kernel_param *kparam, unsigned int num_params);
373 void mod_sysfs_teardown(struct module *mod);
374 void init_param_lock(struct module *mod);
375 #else /* !CONFIG_SYSFS */
mod_sysfs_setup(struct module * mod,const struct load_info * info,struct kernel_param * kparam,unsigned int num_params)376 static inline int mod_sysfs_setup(struct module *mod,
377 const struct load_info *info,
378 struct kernel_param *kparam,
379 unsigned int num_params)
380 {
381 return 0;
382 }
383
mod_sysfs_teardown(struct module * mod)384 static inline void mod_sysfs_teardown(struct module *mod) { }
init_param_lock(struct module * mod)385 static inline void init_param_lock(struct module *mod) { }
386 #endif /* CONFIG_SYSFS */
387
388 #ifdef CONFIG_MODVERSIONS
389 int check_version(const struct load_info *info,
390 const char *symname, struct module *mod, const u32 *crc);
391 void module_layout(struct module *mod, struct modversion_info *ver, struct kernel_param *kp,
392 struct kernel_symbol *ks, struct tracepoint * const *tp);
393 int check_modstruct_version(const struct load_info *info, struct module *mod);
394 int same_magic(const char *amagic, const char *bmagic, bool has_crcs);
395 struct modversion_info_ext {
396 size_t remaining;
397 const u32 *crc;
398 const char *name;
399 };
400 void modversion_ext_start(const struct load_info *info, struct modversion_info_ext *ver);
401 void modversion_ext_advance(struct modversion_info_ext *ver);
402 #define for_each_modversion_info_ext(ver, info) \
403 for (modversion_ext_start(info, &ver); ver.remaining > 0; modversion_ext_advance(&ver))
404 #else /* !CONFIG_MODVERSIONS */
check_version(const struct load_info * info,const char * symname,struct module * mod,const u32 * crc)405 static inline int check_version(const struct load_info *info,
406 const char *symname,
407 struct module *mod,
408 const u32 *crc)
409 {
410 return 1;
411 }
412
check_modstruct_version(const struct load_info * info,struct module * mod)413 static inline int check_modstruct_version(const struct load_info *info,
414 struct module *mod)
415 {
416 return 1;
417 }
418
same_magic(const char * amagic,const char * bmagic,bool has_crcs)419 static inline int same_magic(const char *amagic, const char *bmagic, bool has_crcs)
420 {
421 return strcmp(amagic, bmagic) == 0;
422 }
423 #endif /* CONFIG_MODVERSIONS */
424