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 15 #ifndef ARCH_SHF_SMALL 16 #define ARCH_SHF_SMALL 0 17 #endif 18 19 /* If this is set, the section belongs in the init part of the module */ 20 #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG - 1)) 21 /* Maximum number of characters written by module_flags() */ 22 #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4) 23 24 #ifndef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC 25 #define data_layout core_layout 26 #endif 27 28 /* 29 * Modules' sections will be aligned on page boundaries 30 * to ensure complete separation of code and data, but 31 * only when CONFIG_STRICT_MODULE_RWX=y 32 */ 33 #ifdef CONFIG_STRICT_MODULE_RWX 34 # define strict_align(X) PAGE_ALIGN(X) 35 #else 36 # define strict_align(X) (X) 37 #endif 38 39 extern struct mutex module_mutex; 40 extern struct list_head modules; 41 42 extern struct module_attribute *modinfo_attrs[]; 43 extern size_t modinfo_attrs_count; 44 45 /* Provided by the linker */ 46 extern const struct kernel_symbol __start___ksymtab[]; 47 extern const struct kernel_symbol __stop___ksymtab[]; 48 extern const struct kernel_symbol __start___ksymtab_gpl[]; 49 extern const struct kernel_symbol __stop___ksymtab_gpl[]; 50 extern const s32 __start___kcrctab[]; 51 extern const s32 __start___kcrctab_gpl[]; 52 53 struct load_info { 54 const char *name; 55 /* pointer to module in temporary copy, freed at end of load_module() */ 56 struct module *mod; 57 Elf_Ehdr *hdr; 58 unsigned long len; 59 Elf_Shdr *sechdrs; 60 char *secstrings, *strtab; 61 unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs; 62 struct _ddebug *debug; 63 unsigned int num_debug; 64 bool sig_ok; 65 #ifdef CONFIG_KALLSYMS 66 unsigned long mod_kallsyms_init_off; 67 #endif 68 #ifdef CONFIG_MODULE_DECOMPRESS 69 struct page **pages; 70 unsigned int max_pages; 71 unsigned int used_pages; 72 #endif 73 struct { 74 unsigned int sym, str, mod, vers, info, pcpu; 75 } index; 76 }; 77 78 enum mod_license { 79 NOT_GPL_ONLY, 80 GPL_ONLY, 81 }; 82 83 struct find_symbol_arg { 84 /* Input */ 85 const char *name; 86 bool gplok; 87 bool warn; 88 89 /* Output */ 90 struct module *owner; 91 const s32 *crc; 92 const struct kernel_symbol *sym; 93 enum mod_license license; 94 }; 95 96 int mod_verify_sig(const void *mod, struct load_info *info); 97 int try_to_force_load(struct module *mod, const char *reason); 98 bool find_symbol(struct find_symbol_arg *fsa); 99 struct module *find_module_all(const char *name, size_t len, bool even_unformed); 100 int cmp_name(const void *name, const void *sym); 101 long module_get_offset(struct module *mod, unsigned int *size, Elf_Shdr *sechdr, 102 unsigned int section); 103 char *module_flags(struct module *mod, char *buf); 104 size_t module_flags_taint(unsigned long taints, char *buf); 105 106 static inline void module_assert_mutex_or_preempt(void) 107 { 108 #ifdef CONFIG_LOCKDEP 109 if (unlikely(!debug_locks)) 110 return; 111 112 WARN_ON_ONCE(!rcu_read_lock_sched_held() && 113 !lockdep_is_held(&module_mutex)); 114 #endif 115 } 116 117 static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym) 118 { 119 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS 120 return (unsigned long)offset_to_ptr(&sym->value_offset); 121 #else 122 return sym->value; 123 #endif 124 } 125 126 #ifdef CONFIG_LIVEPATCH 127 int copy_module_elf(struct module *mod, struct load_info *info); 128 void free_module_elf(struct module *mod); 129 #else /* !CONFIG_LIVEPATCH */ 130 static inline int copy_module_elf(struct module *mod, struct load_info *info) 131 { 132 return 0; 133 } 134 135 static inline void free_module_elf(struct module *mod) { } 136 #endif /* CONFIG_LIVEPATCH */ 137 138 static inline bool set_livepatch_module(struct module *mod) 139 { 140 #ifdef CONFIG_LIVEPATCH 141 mod->klp = true; 142 return true; 143 #else 144 return false; 145 #endif 146 } 147 148 #ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING 149 struct mod_unload_taint { 150 struct list_head list; 151 char name[MODULE_NAME_LEN]; 152 unsigned long taints; 153 u64 count; 154 }; 155 156 int try_add_tainted_module(struct module *mod); 157 void print_unloaded_tainted_modules(void); 158 #else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 159 static inline int try_add_tainted_module(struct module *mod) 160 { 161 return 0; 162 } 163 164 static inline void print_unloaded_tainted_modules(void) 165 { 166 } 167 #endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */ 168 169 #ifdef CONFIG_MODULE_DECOMPRESS 170 int module_decompress(struct load_info *info, const void *buf, size_t size); 171 void module_decompress_cleanup(struct load_info *info); 172 #else 173 static inline int module_decompress(struct load_info *info, 174 const void *buf, size_t size) 175 { 176 return -EOPNOTSUPP; 177 } 178 179 static inline void module_decompress_cleanup(struct load_info *info) 180 { 181 } 182 #endif 183 184 struct mod_tree_root { 185 #ifdef CONFIG_MODULES_TREE_LOOKUP 186 struct latch_tree_root root; 187 #endif 188 unsigned long addr_min; 189 unsigned long addr_max; 190 }; 191 192 extern struct mod_tree_root mod_tree; 193 extern struct mod_tree_root mod_data_tree; 194 195 #ifdef CONFIG_MODULES_TREE_LOOKUP 196 void mod_tree_insert(struct module *mod); 197 void mod_tree_remove_init(struct module *mod); 198 void mod_tree_remove(struct module *mod); 199 struct module *mod_find(unsigned long addr, struct mod_tree_root *tree); 200 #else /* !CONFIG_MODULES_TREE_LOOKUP */ 201 202 static inline void mod_tree_insert(struct module *mod) { } 203 static inline void mod_tree_remove_init(struct module *mod) { } 204 static inline void mod_tree_remove(struct module *mod) { } 205 static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree) 206 { 207 struct module *mod; 208 209 list_for_each_entry_rcu(mod, &modules, list, 210 lockdep_is_held(&module_mutex)) { 211 if (within_module(addr, mod)) 212 return mod; 213 } 214 215 return NULL; 216 } 217 #endif /* CONFIG_MODULES_TREE_LOOKUP */ 218 219 void module_enable_ro(const struct module *mod, bool after_init); 220 void module_enable_nx(const struct module *mod); 221 void module_enable_x(const struct module *mod); 222 int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 223 char *secstrings, struct module *mod); 224 bool module_check_misalignment(const 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