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 unsigned long kernel_symbol_value(const struct kernel_symbol *sym) 128 { 129 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS 130 return (unsigned long)offset_to_ptr(&sym->value_offset); 131 #else 132 return sym->value; 133 #endif 134 } 135 136 #ifdef CONFIG_LIVEPATCH 137 int copy_module_elf(struct module *mod, struct load_info *info); 138 void free_module_elf(struct module *mod); 139 #else /* !CONFIG_LIVEPATCH */ 140 static inline int copy_module_elf(struct module *mod, struct load_info *info) 141 { 142 return 0; 143 } 144 145 static inline void free_module_elf(struct module *mod) { } 146 #endif /* CONFIG_LIVEPATCH */ 147 148 static inline bool set_livepatch_module(struct module *mod) 149 { 150 #ifdef CONFIG_LIVEPATCH 151 mod->klp = true; 152 return true; 153 #else 154 return false; 155 #endif 156 } 157 158 /** 159 * enum fail_dup_mod_reason - state at which a duplicate module was detected 160 * 161 * @FAIL_DUP_MOD_BECOMING: the module is read properly, passes all checks but 162 * we've determined that another module with the same name is already loaded 163 * or being processed on our &modules list. This happens on early_mod_check() 164 * right before layout_and_allocate(). The kernel would have already 165 * vmalloc()'d space for the entire module through finit_module(). If 166 * decompression was used two vmap() spaces were used. These failures can 167 * happen when userspace has not seen the module present on the kernel and 168 * tries to load the module multiple times at same time. 169 * @FAIL_DUP_MOD_LOAD: the module has been read properly, passes all validation 170 * checks and the kernel determines that the module was unique and because 171 * of this allocated yet another private kernel copy of the module space in 172 * layout_and_allocate() but after this determined in add_unformed_module() 173 * that another module with the same name is already loaded or being processed. 174 * These failures should be mitigated as much as possible and are indicative 175 * of really fast races in loading modules. Without module decompression 176 * they waste twice as much vmap space. With module decompression three 177 * times the module's size vmap space is wasted. 178 */ 179 enum fail_dup_mod_reason { 180 FAIL_DUP_MOD_BECOMING = 0, 181 FAIL_DUP_MOD_LOAD, 182 }; 183 184 #ifdef CONFIG_MODULE_DEBUGFS 185 extern struct dentry *mod_debugfs_root; 186 #endif 187 188 #ifdef CONFIG_MODULE_STATS 189 190 #define mod_stat_add_long(count, var) atomic_long_add(count, var) 191 #define mod_stat_inc(name) atomic_inc(name) 192 193 extern atomic_long_t total_mod_size; 194 extern atomic_long_t total_text_size; 195 extern atomic_long_t invalid_kread_bytes; 196 extern atomic_long_t invalid_decompress_bytes; 197 198 extern atomic_t modcount; 199 extern atomic_t failed_kreads; 200 extern atomic_t failed_decompress; 201 struct mod_fail_load { 202 struct list_head list; 203 char name[MODULE_NAME_LEN]; 204 atomic_long_t count; 205 unsigned long dup_fail_mask; 206 }; 207 208 int try_add_failed_module(const char *name, enum fail_dup_mod_reason reason); 209 void mod_stat_bump_invalid(struct load_info *info, int flags); 210 void mod_stat_bump_becoming(struct load_info *info, int flags); 211 212 #else 213 214 #define mod_stat_add_long(name, var) 215 #define mod_stat_inc(name) 216 217 static inline int try_add_failed_module(const char *name, 218 enum fail_dup_mod_reason reason) 219 { 220 return 0; 221 } 222 223 static inline void mod_stat_bump_invalid(struct load_info *info, int flags) 224 { 225 } 226 227 static inline void mod_stat_bump_becoming(struct load_info *info, int flags) 228 { 229 } 230 231 #endif /* CONFIG_MODULE_STATS */ 232 233 #ifdef CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS 234 bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret); 235 void kmod_dup_request_announce(char *module_name, int ret); 236 #else 237 static inline bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret) 238 { 239 return false; 240 } 241 242 static inline void kmod_dup_request_announce(char *module_name, int ret) 243 { 244 } 245 #endif 246 247 #ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING 248 struct mod_unload_taint { 249 struct list_head list; 250 char name[MODULE_NAME_LEN]; 251 unsigned long taints; 252 u64 count; 253 }; 254 255 int try_add_tainted_module(struct module *mod); 256 void print_unloaded_tainted_modules(void); 257 #else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 258 static inline int try_add_tainted_module(struct module *mod) 259 { 260 return 0; 261 } 262 263 static inline void print_unloaded_tainted_modules(void) 264 { 265 } 266 #endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 267 268 #ifdef CONFIG_MODULE_DECOMPRESS 269 int module_decompress(struct load_info *info, const void *buf, size_t size); 270 void module_decompress_cleanup(struct load_info *info); 271 #else 272 static inline int module_decompress(struct load_info *info, 273 const void *buf, size_t size) 274 { 275 return -EOPNOTSUPP; 276 } 277 278 static inline void module_decompress_cleanup(struct load_info *info) 279 { 280 } 281 #endif 282 283 struct mod_tree_root { 284 #ifdef CONFIG_MODULES_TREE_LOOKUP 285 struct latch_tree_root root; 286 #endif 287 unsigned long addr_min; 288 unsigned long addr_max; 289 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC 290 unsigned long data_addr_min; 291 unsigned long data_addr_max; 292 #endif 293 }; 294 295 extern struct mod_tree_root mod_tree; 296 297 #ifdef CONFIG_MODULES_TREE_LOOKUP 298 void mod_tree_insert(struct module *mod); 299 void mod_tree_remove_init(struct module *mod); 300 void mod_tree_remove(struct module *mod); 301 struct module *mod_find(unsigned long addr, struct mod_tree_root *tree); 302 #else /* !CONFIG_MODULES_TREE_LOOKUP */ 303 304 static inline void mod_tree_insert(struct module *mod) { } 305 static inline void mod_tree_remove_init(struct module *mod) { } 306 static inline void mod_tree_remove(struct module *mod) { } 307 static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree) 308 { 309 struct module *mod; 310 311 list_for_each_entry_rcu(mod, &modules, list, 312 lockdep_is_held(&module_mutex)) { 313 if (within_module(addr, mod)) 314 return mod; 315 } 316 317 return NULL; 318 } 319 #endif /* CONFIG_MODULES_TREE_LOOKUP */ 320 321 int module_enable_rodata_ro(const struct module *mod); 322 int module_enable_rodata_ro_after_init(const struct module *mod); 323 int module_enable_data_nx(const struct module *mod); 324 int module_enable_text_rox(const struct module *mod); 325 int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, 326 const char *secstrings, 327 const struct module *mod); 328 void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 329 const char *secstrings); 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 u32 *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 struct modversion_info_ext { 388 size_t remaining; 389 const u32 *crc; 390 const char *name; 391 }; 392 void modversion_ext_start(const struct load_info *info, struct modversion_info_ext *ver); 393 void modversion_ext_advance(struct modversion_info_ext *ver); 394 #define for_each_modversion_info_ext(ver, info) \ 395 for (modversion_ext_start(info, &ver); ver.remaining > 0; modversion_ext_advance(&ver)) 396 #else /* !CONFIG_MODVERSIONS */ 397 static inline int check_version(const struct load_info *info, 398 const char *symname, 399 struct module *mod, 400 const u32 *crc) 401 { 402 return 1; 403 } 404 405 static inline int check_modstruct_version(const struct load_info *info, 406 struct module *mod) 407 { 408 return 1; 409 } 410 411 static inline int same_magic(const char *amagic, const char *bmagic, bool has_crcs) 412 { 413 return strcmp(amagic, bmagic) == 0; 414 } 415 #endif /* CONFIG_MODVERSIONS */ 416