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