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 */ 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 char *module_next_tag_pair(char *string, unsigned long *secsize); 100 101 #define for_each_modinfo_entry(entry, info, name) \ 102 for (entry = get_modinfo(info, name); entry; entry = get_next_modinfo(info, name, entry)) 103 104 static inline void module_assert_mutex_or_preempt(void) 105 { 106 #ifdef CONFIG_LOCKDEP 107 if (unlikely(!debug_locks)) 108 return; 109 110 WARN_ON_ONCE(!rcu_read_lock_sched_held() && 111 !lockdep_is_held(&module_mutex)); 112 #endif 113 } 114 115 static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym) 116 { 117 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS 118 return (unsigned long)offset_to_ptr(&sym->value_offset); 119 #else 120 return sym->value; 121 #endif 122 } 123 124 #ifdef CONFIG_LIVEPATCH 125 int copy_module_elf(struct module *mod, struct load_info *info); 126 void free_module_elf(struct module *mod); 127 #else /* !CONFIG_LIVEPATCH */ 128 static inline int copy_module_elf(struct module *mod, struct load_info *info) 129 { 130 return 0; 131 } 132 133 static inline void free_module_elf(struct module *mod) { } 134 #endif /* CONFIG_LIVEPATCH */ 135 136 static inline bool set_livepatch_module(struct module *mod) 137 { 138 #ifdef CONFIG_LIVEPATCH 139 mod->klp = true; 140 return true; 141 #else 142 return false; 143 #endif 144 } 145 146 #ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING 147 struct mod_unload_taint { 148 struct list_head list; 149 char name[MODULE_NAME_LEN]; 150 unsigned long taints; 151 u64 count; 152 }; 153 154 int try_add_tainted_module(struct module *mod); 155 void print_unloaded_tainted_modules(void); 156 #else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 157 static inline int try_add_tainted_module(struct module *mod) 158 { 159 return 0; 160 } 161 162 static inline void print_unloaded_tainted_modules(void) 163 { 164 } 165 #endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 166 167 #ifdef CONFIG_MODULE_DECOMPRESS 168 int module_decompress(struct load_info *info, const void *buf, size_t size); 169 void module_decompress_cleanup(struct load_info *info); 170 #else 171 static inline int module_decompress(struct load_info *info, 172 const void *buf, size_t size) 173 { 174 return -EOPNOTSUPP; 175 } 176 177 static inline void module_decompress_cleanup(struct load_info *info) 178 { 179 } 180 #endif 181 182 struct mod_tree_root { 183 #ifdef CONFIG_MODULES_TREE_LOOKUP 184 struct latch_tree_root root; 185 #endif 186 unsigned long addr_min; 187 unsigned long addr_max; 188 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC 189 unsigned long data_addr_min; 190 unsigned long data_addr_max; 191 #endif 192 }; 193 194 extern struct mod_tree_root mod_tree; 195 196 #ifdef CONFIG_MODULES_TREE_LOOKUP 197 void mod_tree_insert(struct module *mod); 198 void mod_tree_remove_init(struct module *mod); 199 void mod_tree_remove(struct module *mod); 200 struct module *mod_find(unsigned long addr, struct mod_tree_root *tree); 201 #else /* !CONFIG_MODULES_TREE_LOOKUP */ 202 203 static inline void mod_tree_insert(struct module *mod) { } 204 static inline void mod_tree_remove_init(struct module *mod) { } 205 static inline void mod_tree_remove(struct module *mod) { } 206 static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree) 207 { 208 struct module *mod; 209 210 list_for_each_entry_rcu(mod, &modules, list, 211 lockdep_is_held(&module_mutex)) { 212 if (within_module(addr, mod)) 213 return mod; 214 } 215 216 return NULL; 217 } 218 #endif /* CONFIG_MODULES_TREE_LOOKUP */ 219 220 void module_enable_ro(const struct module *mod, bool after_init); 221 void module_enable_nx(const struct module *mod); 222 void module_enable_x(const struct module *mod); 223 int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 224 char *secstrings, struct module *mod); 225 226 #ifdef CONFIG_MODULE_SIG 227 int module_sig_check(struct load_info *info, int flags); 228 #else /* !CONFIG_MODULE_SIG */ 229 static inline int module_sig_check(struct load_info *info, int flags) 230 { 231 return 0; 232 } 233 #endif /* !CONFIG_MODULE_SIG */ 234 235 #ifdef CONFIG_DEBUG_KMEMLEAK 236 void kmemleak_load_module(const struct module *mod, const struct load_info *info); 237 #else /* !CONFIG_DEBUG_KMEMLEAK */ 238 static inline void kmemleak_load_module(const struct module *mod, 239 const struct load_info *info) { } 240 #endif /* CONFIG_DEBUG_KMEMLEAK */ 241 242 #ifdef CONFIG_KALLSYMS 243 void init_build_id(struct module *mod, const struct load_info *info); 244 void layout_symtab(struct module *mod, struct load_info *info); 245 void add_kallsyms(struct module *mod, const struct load_info *info); 246 unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name); 247 248 static inline bool sect_empty(const Elf_Shdr *sect) 249 { 250 return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0; 251 } 252 #else /* !CONFIG_KALLSYMS */ 253 static inline void init_build_id(struct module *mod, const struct load_info *info) { } 254 static inline void layout_symtab(struct module *mod, struct load_info *info) { } 255 static inline void add_kallsyms(struct module *mod, const struct load_info *info) { } 256 #endif /* CONFIG_KALLSYMS */ 257 258 #ifdef CONFIG_SYSFS 259 int mod_sysfs_setup(struct module *mod, const struct load_info *info, 260 struct kernel_param *kparam, unsigned int num_params); 261 void mod_sysfs_teardown(struct module *mod); 262 void init_param_lock(struct module *mod); 263 #else /* !CONFIG_SYSFS */ 264 static inline int mod_sysfs_setup(struct module *mod, 265 const struct load_info *info, 266 struct kernel_param *kparam, 267 unsigned int num_params) 268 { 269 return 0; 270 } 271 272 static inline void mod_sysfs_teardown(struct module *mod) { } 273 static inline void init_param_lock(struct module *mod) { } 274 #endif /* CONFIG_SYSFS */ 275 276 #ifdef CONFIG_MODVERSIONS 277 int check_version(const struct load_info *info, 278 const char *symname, struct module *mod, const s32 *crc); 279 void module_layout(struct module *mod, struct modversion_info *ver, struct kernel_param *kp, 280 struct kernel_symbol *ks, struct tracepoint * const *tp); 281 int check_modstruct_version(const struct load_info *info, struct module *mod); 282 int same_magic(const char *amagic, const char *bmagic, bool has_crcs); 283 #else /* !CONFIG_MODVERSIONS */ 284 static inline int check_version(const struct load_info *info, 285 const char *symname, 286 struct module *mod, 287 const s32 *crc) 288 { 289 return 1; 290 } 291 292 static inline int check_modstruct_version(const struct load_info *info, 293 struct module *mod) 294 { 295 return 1; 296 } 297 298 static inline int same_magic(const char *amagic, const char *bmagic, bool has_crcs) 299 { 300 return strcmp(amagic, bmagic) == 0; 301 } 302 #endif /* CONFIG_MODVERSIONS */ 303