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 ([email protected]) 6 */ 7 8 #include <linux/elf.h> 9 #include <linux/compiler.h> 10 #include <linux/module.h> 11 #include <linux/mutex.h> 12 #include <linux/rculist.h> 13 #include <linux/rcupdate.h> 14 #include <linux/mm.h> 15 16 #ifndef ARCH_SHF_SMALL 17 #define ARCH_SHF_SMALL 0 18 #endif 19 20 /* 21 * Use highest 4 bits of sh_entsize to store the mod_mem_type of this 22 * section. This leaves 28 bits for offset on 32-bit systems, which is 23 * about 256 MiB (WARN_ON_ONCE if we exceed that). 24 */ 25 26 #define SH_ENTSIZE_TYPE_BITS 4 27 #define SH_ENTSIZE_TYPE_SHIFT (BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS) 28 #define SH_ENTSIZE_TYPE_MASK ((1UL << SH_ENTSIZE_TYPE_BITS) - 1) 29 #define SH_ENTSIZE_OFFSET_MASK ((1UL << (BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS)) - 1) 30 31 /* Maximum number of characters written by module_flags() */ 32 #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4) 33 34 extern struct mutex module_mutex; 35 extern struct list_head modules; 36 37 extern struct module_attribute *modinfo_attrs[]; 38 extern size_t modinfo_attrs_count; 39 40 /* Provided by the linker */ 41 extern const struct kernel_symbol __start___ksymtab[]; 42 extern const struct kernel_symbol __stop___ksymtab[]; 43 extern const struct kernel_symbol __start___ksymtab_gpl[]; 44 extern const struct kernel_symbol __stop___ksymtab_gpl[]; 45 extern const s32 __start___kcrctab[]; 46 extern const s32 __start___kcrctab_gpl[]; 47 48 struct load_info { 49 const char *name; 50 /* pointer to module in temporary copy, freed at end of load_module() */ 51 struct module *mod; 52 Elf_Ehdr *hdr; 53 unsigned long len; 54 Elf_Shdr *sechdrs; 55 char *secstrings, *strtab; 56 unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs; 57 bool sig_ok; 58 #ifdef CONFIG_KALLSYMS 59 unsigned long mod_kallsyms_init_off; 60 #endif 61 #ifdef CONFIG_MODULE_DECOMPRESS 62 struct page **pages; 63 unsigned int max_pages; 64 unsigned int used_pages; 65 #endif 66 struct { 67 unsigned int sym, str, mod, vers, info, pcpu; 68 } index; 69 }; 70 71 enum mod_license { 72 NOT_GPL_ONLY, 73 GPL_ONLY, 74 }; 75 76 struct find_symbol_arg { 77 /* Input */ 78 const char *name; 79 bool gplok; 80 bool warn; 81 82 /* Output */ 83 struct module *owner; 84 const s32 *crc; 85 const struct kernel_symbol *sym; 86 enum mod_license license; 87 }; 88 89 int mod_verify_sig(const void *mod, struct load_info *info); 90 int try_to_force_load(struct module *mod, const char *reason); 91 bool find_symbol(struct find_symbol_arg *fsa); 92 struct module *find_module_all(const char *name, size_t len, bool even_unformed); 93 int cmp_name(const void *name, const void *sym); 94 long module_get_offset_and_type(struct module *mod, enum mod_mem_type type, 95 Elf_Shdr *sechdr, unsigned int section); 96 char *module_flags(struct module *mod, char *buf, bool show_state); 97 size_t module_flags_taint(unsigned long taints, char *buf); 98 99 static inline void module_assert_mutex_or_preempt(void) 100 { 101 #ifdef CONFIG_LOCKDEP 102 if (unlikely(!debug_locks)) 103 return; 104 105 WARN_ON_ONCE(!rcu_read_lock_sched_held() && 106 !lockdep_is_held(&module_mutex)); 107 #endif 108 } 109 110 static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym) 111 { 112 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS 113 return (unsigned long)offset_to_ptr(&sym->value_offset); 114 #else 115 return sym->value; 116 #endif 117 } 118 119 #ifdef CONFIG_LIVEPATCH 120 int copy_module_elf(struct module *mod, struct load_info *info); 121 void free_module_elf(struct module *mod); 122 #else /* !CONFIG_LIVEPATCH */ 123 static inline int copy_module_elf(struct module *mod, struct load_info *info) 124 { 125 return 0; 126 } 127 128 static inline void free_module_elf(struct module *mod) { } 129 #endif /* CONFIG_LIVEPATCH */ 130 131 static inline bool set_livepatch_module(struct module *mod) 132 { 133 #ifdef CONFIG_LIVEPATCH 134 mod->klp = true; 135 return true; 136 #else 137 return false; 138 #endif 139 } 140 141 #ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING 142 struct mod_unload_taint { 143 struct list_head list; 144 char name[MODULE_NAME_LEN]; 145 unsigned long taints; 146 u64 count; 147 }; 148 149 int try_add_tainted_module(struct module *mod); 150 void print_unloaded_tainted_modules(void); 151 #else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 152 static inline int try_add_tainted_module(struct module *mod) 153 { 154 return 0; 155 } 156 157 static inline void print_unloaded_tainted_modules(void) 158 { 159 } 160 #endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 161 162 #ifdef CONFIG_MODULE_DECOMPRESS 163 int module_decompress(struct load_info *info, const void *buf, size_t size); 164 void module_decompress_cleanup(struct load_info *info); 165 #else 166 static inline int module_decompress(struct load_info *info, 167 const void *buf, size_t size) 168 { 169 return -EOPNOTSUPP; 170 } 171 172 static inline void module_decompress_cleanup(struct load_info *info) 173 { 174 } 175 #endif 176 177 struct mod_tree_root { 178 #ifdef CONFIG_MODULES_TREE_LOOKUP 179 struct latch_tree_root root; 180 #endif 181 unsigned long addr_min; 182 unsigned long addr_max; 183 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC 184 unsigned long data_addr_min; 185 unsigned long data_addr_max; 186 #endif 187 }; 188 189 extern struct mod_tree_root mod_tree; 190 191 #ifdef CONFIG_MODULES_TREE_LOOKUP 192 void mod_tree_insert(struct module *mod); 193 void mod_tree_remove_init(struct module *mod); 194 void mod_tree_remove(struct module *mod); 195 struct module *mod_find(unsigned long addr, struct mod_tree_root *tree); 196 #else /* !CONFIG_MODULES_TREE_LOOKUP */ 197 198 static inline void mod_tree_insert(struct module *mod) { } 199 static inline void mod_tree_remove_init(struct module *mod) { } 200 static inline void mod_tree_remove(struct module *mod) { } 201 static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree) 202 { 203 struct module *mod; 204 205 list_for_each_entry_rcu(mod, &modules, list, 206 lockdep_is_held(&module_mutex)) { 207 if (within_module(addr, mod)) 208 return mod; 209 } 210 211 return NULL; 212 } 213 #endif /* CONFIG_MODULES_TREE_LOOKUP */ 214 215 void module_enable_ro(const struct module *mod, bool after_init); 216 void module_enable_nx(const struct module *mod); 217 void module_enable_x(const struct module *mod); 218 int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 219 char *secstrings, struct module *mod); 220 221 #ifdef CONFIG_MODULE_SIG 222 int module_sig_check(struct load_info *info, int flags); 223 #else /* !CONFIG_MODULE_SIG */ 224 static inline int module_sig_check(struct load_info *info, int flags) 225 { 226 return 0; 227 } 228 #endif /* !CONFIG_MODULE_SIG */ 229 230 #ifdef CONFIG_DEBUG_KMEMLEAK 231 void kmemleak_load_module(const struct module *mod, const struct load_info *info); 232 #else /* !CONFIG_DEBUG_KMEMLEAK */ 233 static inline void kmemleak_load_module(const struct module *mod, 234 const struct load_info *info) { } 235 #endif /* CONFIG_DEBUG_KMEMLEAK */ 236 237 #ifdef CONFIG_KALLSYMS 238 void init_build_id(struct module *mod, const struct load_info *info); 239 void layout_symtab(struct module *mod, struct load_info *info); 240 void add_kallsyms(struct module *mod, const struct load_info *info); 241 unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name); 242 243 static inline bool sect_empty(const Elf_Shdr *sect) 244 { 245 return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0; 246 } 247 #else /* !CONFIG_KALLSYMS */ 248 static inline void init_build_id(struct module *mod, const struct load_info *info) { } 249 static inline void layout_symtab(struct module *mod, struct load_info *info) { } 250 static inline void add_kallsyms(struct module *mod, const struct load_info *info) { } 251 #endif /* CONFIG_KALLSYMS */ 252 253 #ifdef CONFIG_SYSFS 254 int mod_sysfs_setup(struct module *mod, const struct load_info *info, 255 struct kernel_param *kparam, unsigned int num_params); 256 void mod_sysfs_teardown(struct module *mod); 257 void init_param_lock(struct module *mod); 258 #else /* !CONFIG_SYSFS */ 259 static inline int mod_sysfs_setup(struct module *mod, 260 const struct load_info *info, 261 struct kernel_param *kparam, 262 unsigned int num_params) 263 { 264 return 0; 265 } 266 267 static inline void mod_sysfs_teardown(struct module *mod) { } 268 static inline void init_param_lock(struct module *mod) { } 269 #endif /* CONFIG_SYSFS */ 270 271 #ifdef CONFIG_MODVERSIONS 272 int check_version(const struct load_info *info, 273 const char *symname, struct module *mod, const s32 *crc); 274 void module_layout(struct module *mod, struct modversion_info *ver, struct kernel_param *kp, 275 struct kernel_symbol *ks, struct tracepoint * const *tp); 276 int check_modstruct_version(const struct load_info *info, struct module *mod); 277 int same_magic(const char *amagic, const char *bmagic, bool has_crcs); 278 #else /* !CONFIG_MODVERSIONS */ 279 static inline int check_version(const struct load_info *info, 280 const char *symname, 281 struct module *mod, 282 const s32 *crc) 283 { 284 return 1; 285 } 286 287 static inline int check_modstruct_version(const struct load_info *info, 288 struct module *mod) 289 { 290 return 1; 291 } 292 293 static inline int same_magic(const char *amagic, const char *bmagic, bool has_crcs) 294 { 295 return strcmp(amagic, bmagic) == 0; 296 } 297 #endif /* CONFIG_MODVERSIONS */ 298