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 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; 84 unsigned int str; 85 unsigned int mod; 86 unsigned int vers; 87 unsigned int info; 88 unsigned int pcpu; 89 unsigned int vers_ext_crc; 90 unsigned int vers_ext_name; 91 } index; 92 }; 93 94 enum mod_license { 95 NOT_GPL_ONLY, 96 GPL_ONLY, 97 }; 98 99 struct find_symbol_arg { 100 /* Input */ 101 const char *name; 102 bool gplok; 103 bool warn; 104 105 /* Output */ 106 struct module *owner; 107 const u32 *crc; 108 const struct kernel_symbol *sym; 109 enum mod_license license; 110 }; 111 112 int mod_verify_sig(const void *mod, struct load_info *info); 113 int try_to_force_load(struct module *mod, const char *reason); 114 bool find_symbol(struct find_symbol_arg *fsa); 115 struct module *find_module_all(const char *name, size_t len, bool even_unformed); 116 int cmp_name(const void *name, const void *sym); 117 long module_get_offset_and_type(struct module *mod, enum mod_mem_type type, 118 Elf_Shdr *sechdr, unsigned int section); 119 char *module_flags(struct module *mod, char *buf, bool show_state); 120 size_t module_flags_taint(unsigned long taints, char *buf); 121 122 char *module_next_tag_pair(char *string, unsigned long *secsize); 123 124 #define for_each_modinfo_entry(entry, info, name) \ 125 for (entry = get_modinfo(info, name); entry; entry = get_next_modinfo(info, name, entry)) 126 127 static inline void module_assert_mutex_or_preempt(void) 128 { 129 #ifdef CONFIG_LOCKDEP 130 if (unlikely(!debug_locks)) 131 return; 132 133 WARN_ON_ONCE(!rcu_read_lock_sched_held() && 134 !lockdep_is_held(&module_mutex)); 135 #endif 136 } 137 138 static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym) 139 { 140 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS 141 return (unsigned long)offset_to_ptr(&sym->value_offset); 142 #else 143 return sym->value; 144 #endif 145 } 146 147 #ifdef CONFIG_LIVEPATCH 148 int copy_module_elf(struct module *mod, struct load_info *info); 149 void free_module_elf(struct module *mod); 150 #else /* !CONFIG_LIVEPATCH */ 151 static inline int copy_module_elf(struct module *mod, struct load_info *info) 152 { 153 return 0; 154 } 155 156 static inline void free_module_elf(struct module *mod) { } 157 #endif /* CONFIG_LIVEPATCH */ 158 159 static inline bool set_livepatch_module(struct module *mod) 160 { 161 #ifdef CONFIG_LIVEPATCH 162 mod->klp = true; 163 return true; 164 #else 165 return false; 166 #endif 167 } 168 169 /** 170 * enum fail_dup_mod_reason - state at which a duplicate module was detected 171 * 172 * @FAIL_DUP_MOD_BECOMING: the module is read properly, passes all checks but 173 * we've determined that another module with the same name is already loaded 174 * or being processed on our &modules list. This happens on early_mod_check() 175 * right before layout_and_allocate(). The kernel would have already 176 * vmalloc()'d space for the entire module through finit_module(). If 177 * decompression was used two vmap() spaces were used. These failures can 178 * happen when userspace has not seen the module present on the kernel and 179 * tries to load the module multiple times at same time. 180 * @FAIL_DUP_MOD_LOAD: the module has been read properly, passes all validation 181 * checks and the kernel determines that the module was unique and because 182 * of this allocated yet another private kernel copy of the module space in 183 * layout_and_allocate() but after this determined in add_unformed_module() 184 * that another module with the same name is already loaded or being processed. 185 * These failures should be mitigated as much as possible and are indicative 186 * of really fast races in loading modules. Without module decompression 187 * they waste twice as much vmap space. With module decompression three 188 * times the module's size vmap space is wasted. 189 */ 190 enum fail_dup_mod_reason { 191 FAIL_DUP_MOD_BECOMING = 0, 192 FAIL_DUP_MOD_LOAD, 193 }; 194 195 #ifdef CONFIG_MODULE_DEBUGFS 196 extern struct dentry *mod_debugfs_root; 197 #endif 198 199 #ifdef CONFIG_MODULE_STATS 200 201 #define mod_stat_add_long(count, var) atomic_long_add(count, var) 202 #define mod_stat_inc(name) atomic_inc(name) 203 204 extern atomic_long_t total_mod_size; 205 extern atomic_long_t total_text_size; 206 extern atomic_long_t invalid_kread_bytes; 207 extern atomic_long_t invalid_decompress_bytes; 208 209 extern atomic_t modcount; 210 extern atomic_t failed_kreads; 211 extern atomic_t failed_decompress; 212 struct mod_fail_load { 213 struct list_head list; 214 char name[MODULE_NAME_LEN]; 215 atomic_long_t count; 216 unsigned long dup_fail_mask; 217 }; 218 219 int try_add_failed_module(const char *name, enum fail_dup_mod_reason reason); 220 void mod_stat_bump_invalid(struct load_info *info, int flags); 221 void mod_stat_bump_becoming(struct load_info *info, int flags); 222 223 #else 224 225 #define mod_stat_add_long(name, var) 226 #define mod_stat_inc(name) 227 228 static inline int try_add_failed_module(const char *name, 229 enum fail_dup_mod_reason reason) 230 { 231 return 0; 232 } 233 234 static inline void mod_stat_bump_invalid(struct load_info *info, int flags) 235 { 236 } 237 238 static inline void mod_stat_bump_becoming(struct load_info *info, int flags) 239 { 240 } 241 242 #endif /* CONFIG_MODULE_STATS */ 243 244 #ifdef CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS 245 bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret); 246 void kmod_dup_request_announce(char *module_name, int ret); 247 #else 248 static inline bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret) 249 { 250 return false; 251 } 252 253 static inline void kmod_dup_request_announce(char *module_name, int ret) 254 { 255 } 256 #endif 257 258 #ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING 259 struct mod_unload_taint { 260 struct list_head list; 261 char name[MODULE_NAME_LEN]; 262 unsigned long taints; 263 u64 count; 264 }; 265 266 int try_add_tainted_module(struct module *mod); 267 void print_unloaded_tainted_modules(void); 268 #else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 269 static inline int try_add_tainted_module(struct module *mod) 270 { 271 return 0; 272 } 273 274 static inline void print_unloaded_tainted_modules(void) 275 { 276 } 277 #endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 278 279 #ifdef CONFIG_MODULE_DECOMPRESS 280 int module_decompress(struct load_info *info, const void *buf, size_t size); 281 void module_decompress_cleanup(struct load_info *info); 282 #else 283 static inline int module_decompress(struct load_info *info, 284 const void *buf, size_t size) 285 { 286 return -EOPNOTSUPP; 287 } 288 289 static inline void module_decompress_cleanup(struct load_info *info) 290 { 291 } 292 #endif 293 294 struct mod_tree_root { 295 #ifdef CONFIG_MODULES_TREE_LOOKUP 296 struct latch_tree_root root; 297 #endif 298 unsigned long addr_min; 299 unsigned long addr_max; 300 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC 301 unsigned long data_addr_min; 302 unsigned long data_addr_max; 303 #endif 304 }; 305 306 extern struct mod_tree_root mod_tree; 307 308 #ifdef CONFIG_MODULES_TREE_LOOKUP 309 void mod_tree_insert(struct module *mod); 310 void mod_tree_remove_init(struct module *mod); 311 void mod_tree_remove(struct module *mod); 312 struct module *mod_find(unsigned long addr, struct mod_tree_root *tree); 313 #else /* !CONFIG_MODULES_TREE_LOOKUP */ 314 315 static inline void mod_tree_insert(struct module *mod) { } 316 static inline void mod_tree_remove_init(struct module *mod) { } 317 static inline void mod_tree_remove(struct module *mod) { } 318 static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree) 319 { 320 struct module *mod; 321 322 list_for_each_entry_rcu(mod, &modules, list, 323 lockdep_is_held(&module_mutex)) { 324 if (within_module(addr, mod)) 325 return mod; 326 } 327 328 return NULL; 329 } 330 #endif /* CONFIG_MODULES_TREE_LOOKUP */ 331 332 int module_enable_rodata_ro(const struct module *mod); 333 int module_enable_rodata_ro_after_init(const struct module *mod); 334 int module_enable_data_nx(const struct module *mod); 335 int module_enable_text_rox(const struct module *mod); 336 int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 337 char *secstrings, struct module *mod); 338 339 #ifdef CONFIG_MODULE_SIG 340 int module_sig_check(struct load_info *info, int flags); 341 #else /* !CONFIG_MODULE_SIG */ 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 */ 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); 359 360 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 */ 365 static inline void init_build_id(struct module *mod, const struct load_info *info) { } 366 static inline void layout_symtab(struct module *mod, 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 */ 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 } 383 384 static inline void mod_sysfs_teardown(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 */ 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 } 412 413 static inline int check_modstruct_version(const struct load_info *info, 414 struct module *mod) 415 { 416 return 1; 417 } 418 419 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