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 struct module_attribute *modinfo_attrs[]; 51 extern 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 s32 __start___kcrctab[]; 59 extern const s32 __start___kcrctab_gpl[]; 60 61 struct load_info { 62 const char *name; 63 /* pointer to module in temporary copy, freed at end of load_module() */ 64 struct module *mod; 65 Elf_Ehdr *hdr; 66 unsigned long len; 67 Elf_Shdr *sechdrs; 68 char *secstrings, *strtab; 69 unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs; 70 bool sig_ok; 71 #ifdef CONFIG_KALLSYMS 72 unsigned long mod_kallsyms_init_off; 73 #endif 74 #ifdef CONFIG_MODULE_DECOMPRESS 75 #ifdef CONFIG_MODULE_STATS 76 unsigned long compressed_len; 77 #endif 78 struct page **pages; 79 unsigned int max_pages; 80 unsigned int used_pages; 81 #endif 82 struct { 83 unsigned int sym, str, mod, vers, info, pcpu; 84 } index; 85 }; 86 87 enum mod_license { 88 NOT_GPL_ONLY, 89 GPL_ONLY, 90 }; 91 92 struct find_symbol_arg { 93 /* Input */ 94 const char *name; 95 bool gplok; 96 bool warn; 97 98 /* Output */ 99 struct module *owner; 100 const s32 *crc; 101 const struct kernel_symbol *sym; 102 enum mod_license license; 103 }; 104 105 int mod_verify_sig(const void *mod, struct load_info *info); 106 int try_to_force_load(struct module *mod, const char *reason); 107 bool find_symbol(struct find_symbol_arg *fsa); 108 struct module *find_module_all(const char *name, size_t len, bool even_unformed); 109 int cmp_name(const void *name, const void *sym); 110 long module_get_offset_and_type(struct module *mod, enum mod_mem_type type, 111 Elf_Shdr *sechdr, unsigned int section); 112 char *module_flags(struct module *mod, char *buf, bool show_state); 113 size_t module_flags_taint(unsigned long taints, char *buf); 114 115 char *module_next_tag_pair(char *string, unsigned long *secsize); 116 117 #define for_each_modinfo_entry(entry, info, name) \ 118 for (entry = get_modinfo(info, name); entry; entry = get_next_modinfo(info, name, entry)) 119 120 static inline void module_assert_mutex_or_preempt(void) 121 { 122 #ifdef CONFIG_LOCKDEP 123 if (unlikely(!debug_locks)) 124 return; 125 126 WARN_ON_ONCE(!rcu_read_lock_sched_held() && 127 !lockdep_is_held(&module_mutex)); 128 #endif 129 } 130 131 static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym) 132 { 133 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS 134 return (unsigned long)offset_to_ptr(&sym->value_offset); 135 #else 136 return sym->value; 137 #endif 138 } 139 140 #ifdef CONFIG_LIVEPATCH 141 int copy_module_elf(struct module *mod, struct load_info *info); 142 void free_module_elf(struct module *mod); 143 #else /* !CONFIG_LIVEPATCH */ 144 static inline int copy_module_elf(struct module *mod, struct load_info *info) 145 { 146 return 0; 147 } 148 149 static inline void free_module_elf(struct module *mod) { } 150 #endif /* CONFIG_LIVEPATCH */ 151 152 static inline bool set_livepatch_module(struct module *mod) 153 { 154 #ifdef CONFIG_LIVEPATCH 155 mod->klp = true; 156 return true; 157 #else 158 return false; 159 #endif 160 } 161 162 /** 163 * enum fail_dup_mod_reason - state at which a duplicate module was detected 164 * 165 * @FAIL_DUP_MOD_BECOMING: the module is read properly, passes all checks but 166 * we've determined that another module with the same name is already loaded 167 * or being processed on our &modules list. This happens on early_mod_check() 168 * right before layout_and_allocate(). The kernel would have already 169 * vmalloc()'d space for the entire module through finit_module(). If 170 * decompression was used two vmap() spaces were used. These failures can 171 * happen when userspace has not seen the module present on the kernel and 172 * tries to load the module multiple times at same time. 173 * @FAIL_DUP_MOD_LOAD: the module has been read properly, passes all validation 174 * checks and the kernel determines that the module was unique and because 175 * of this allocated yet another private kernel copy of the module space in 176 * layout_and_allocate() but after this determined in add_unformed_module() 177 * that another module with the same name is already loaded or being processed. 178 * These failures should be mitigated as much as possible and are indicative 179 * of really fast races in loading modules. Without module decompression 180 * they waste twice as much vmap space. With module decompression three 181 * times the module's size vmap space is wasted. 182 */ 183 enum fail_dup_mod_reason { 184 FAIL_DUP_MOD_BECOMING = 0, 185 FAIL_DUP_MOD_LOAD, 186 }; 187 188 #ifdef CONFIG_MODULE_DEBUGFS 189 extern struct dentry *mod_debugfs_root; 190 #endif 191 192 #ifdef CONFIG_MODULE_STATS 193 194 #define mod_stat_add_long(count, var) atomic_long_add(count, var) 195 #define mod_stat_inc(name) atomic_inc(name) 196 197 extern atomic_long_t total_mod_size; 198 extern atomic_long_t total_text_size; 199 extern atomic_long_t invalid_kread_bytes; 200 extern atomic_long_t invalid_decompress_bytes; 201 202 extern atomic_t modcount; 203 extern atomic_t failed_kreads; 204 extern atomic_t failed_decompress; 205 struct mod_fail_load { 206 struct list_head list; 207 char name[MODULE_NAME_LEN]; 208 atomic_long_t count; 209 unsigned long dup_fail_mask; 210 }; 211 212 int try_add_failed_module(const char *name, enum fail_dup_mod_reason reason); 213 void mod_stat_bump_invalid(struct load_info *info, int flags); 214 void mod_stat_bump_becoming(struct load_info *info, int flags); 215 216 #else 217 218 #define mod_stat_add_long(name, var) 219 #define mod_stat_inc(name) 220 221 static inline int try_add_failed_module(const char *name, 222 enum fail_dup_mod_reason reason) 223 { 224 return 0; 225 } 226 227 static inline void mod_stat_bump_invalid(struct load_info *info, int flags) 228 { 229 } 230 231 static inline void mod_stat_bump_becoming(struct load_info *info, int flags) 232 { 233 } 234 235 #endif /* CONFIG_MODULE_STATS */ 236 237 #ifdef CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS 238 bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret); 239 void kmod_dup_request_announce(char *module_name, int ret); 240 #else 241 static inline bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret) 242 { 243 return false; 244 } 245 246 static inline void kmod_dup_request_announce(char *module_name, int ret) 247 { 248 } 249 #endif 250 251 #ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING 252 struct mod_unload_taint { 253 struct list_head list; 254 char name[MODULE_NAME_LEN]; 255 unsigned long taints; 256 u64 count; 257 }; 258 259 int try_add_tainted_module(struct module *mod); 260 void print_unloaded_tainted_modules(void); 261 #else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 262 static inline int try_add_tainted_module(struct module *mod) 263 { 264 return 0; 265 } 266 267 static inline void print_unloaded_tainted_modules(void) 268 { 269 } 270 #endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 271 272 #ifdef CONFIG_MODULE_DECOMPRESS 273 int module_decompress(struct load_info *info, const void *buf, size_t size); 274 void module_decompress_cleanup(struct load_info *info); 275 #else 276 static inline int module_decompress(struct load_info *info, 277 const void *buf, size_t size) 278 { 279 return -EOPNOTSUPP; 280 } 281 282 static inline void module_decompress_cleanup(struct load_info *info) 283 { 284 } 285 #endif 286 287 struct mod_tree_root { 288 #ifdef CONFIG_MODULES_TREE_LOOKUP 289 struct latch_tree_root root; 290 #endif 291 unsigned long addr_min; 292 unsigned long addr_max; 293 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC 294 unsigned long data_addr_min; 295 unsigned long data_addr_max; 296 #endif 297 }; 298 299 extern struct mod_tree_root mod_tree; 300 301 #ifdef CONFIG_MODULES_TREE_LOOKUP 302 void mod_tree_insert(struct module *mod); 303 void mod_tree_remove_init(struct module *mod); 304 void mod_tree_remove(struct module *mod); 305 struct module *mod_find(unsigned long addr, struct mod_tree_root *tree); 306 #else /* !CONFIG_MODULES_TREE_LOOKUP */ 307 308 static inline void mod_tree_insert(struct module *mod) { } 309 static inline void mod_tree_remove_init(struct module *mod) { } 310 static inline void mod_tree_remove(struct module *mod) { } 311 static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree) 312 { 313 struct module *mod; 314 315 list_for_each_entry_rcu(mod, &modules, list, 316 lockdep_is_held(&module_mutex)) { 317 if (within_module(addr, mod)) 318 return mod; 319 } 320 321 return NULL; 322 } 323 #endif /* CONFIG_MODULES_TREE_LOOKUP */ 324 325 void module_enable_ro(const struct module *mod, bool after_init); 326 void module_enable_nx(const struct module *mod); 327 void module_enable_x(const struct module *mod); 328 int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 329 char *secstrings, struct module *mod); 330 331 #ifdef CONFIG_MODULE_SIG 332 int module_sig_check(struct load_info *info, int flags); 333 #else /* !CONFIG_MODULE_SIG */ 334 static inline int module_sig_check(struct load_info *info, int flags) 335 { 336 return 0; 337 } 338 #endif /* !CONFIG_MODULE_SIG */ 339 340 #ifdef CONFIG_DEBUG_KMEMLEAK 341 void kmemleak_load_module(const struct module *mod, const struct load_info *info); 342 #else /* !CONFIG_DEBUG_KMEMLEAK */ 343 static inline void kmemleak_load_module(const struct module *mod, 344 const struct load_info *info) { } 345 #endif /* CONFIG_DEBUG_KMEMLEAK */ 346 347 #ifdef CONFIG_KALLSYMS 348 void init_build_id(struct module *mod, const struct load_info *info); 349 void layout_symtab(struct module *mod, struct load_info *info); 350 void add_kallsyms(struct module *mod, const struct load_info *info); 351 352 static inline bool sect_empty(const Elf_Shdr *sect) 353 { 354 return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0; 355 } 356 #else /* !CONFIG_KALLSYMS */ 357 static inline void init_build_id(struct module *mod, const struct load_info *info) { } 358 static inline void layout_symtab(struct module *mod, struct load_info *info) { } 359 static inline void add_kallsyms(struct module *mod, const struct load_info *info) { } 360 #endif /* CONFIG_KALLSYMS */ 361 362 #ifdef CONFIG_SYSFS 363 int mod_sysfs_setup(struct module *mod, const struct load_info *info, 364 struct kernel_param *kparam, unsigned int num_params); 365 void mod_sysfs_teardown(struct module *mod); 366 void init_param_lock(struct module *mod); 367 #else /* !CONFIG_SYSFS */ 368 static inline int mod_sysfs_setup(struct module *mod, 369 const struct load_info *info, 370 struct kernel_param *kparam, 371 unsigned int num_params) 372 { 373 return 0; 374 } 375 376 static inline void mod_sysfs_teardown(struct module *mod) { } 377 static inline void init_param_lock(struct module *mod) { } 378 #endif /* CONFIG_SYSFS */ 379 380 #ifdef CONFIG_MODVERSIONS 381 int check_version(const struct load_info *info, 382 const char *symname, struct module *mod, const s32 *crc); 383 void module_layout(struct module *mod, struct modversion_info *ver, struct kernel_param *kp, 384 struct kernel_symbol *ks, struct tracepoint * const *tp); 385 int check_modstruct_version(const struct load_info *info, struct module *mod); 386 int same_magic(const char *amagic, const char *bmagic, bool has_crcs); 387 #else /* !CONFIG_MODVERSIONS */ 388 static inline int check_version(const struct load_info *info, 389 const char *symname, 390 struct module *mod, 391 const s32 *crc) 392 { 393 return 1; 394 } 395 396 static inline int check_modstruct_version(const struct load_info *info, 397 struct module *mod) 398 { 399 return 1; 400 } 401 402 static inline int same_magic(const char *amagic, const char *bmagic, bool has_crcs) 403 { 404 return strcmp(amagic, bmagic) == 0; 405 } 406 #endif /* CONFIG_MODVERSIONS */ 407