1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_STRING_H_ 3 #define _LINUX_STRING_H_ 4 5 6 #include <linux/compiler.h> /* for inline */ 7 #include <linux/types.h> /* for size_t */ 8 #include <linux/stddef.h> /* for NULL */ 9 #include <stdarg.h> 10 #include <uapi/linux/string.h> 11 12 extern char *strndup_user(const char __user *, long); 13 extern void *memdup_user(const void __user *, size_t); 14 extern void *vmemdup_user(const void __user *, size_t); 15 extern void *memdup_user_nul(const void __user *, size_t); 16 17 /* 18 * Include machine specific inline routines 19 */ 20 #include <asm/string.h> 21 22 #ifndef __HAVE_ARCH_STRCPY 23 extern char * strcpy(char *,const char *); 24 #endif 25 #ifndef __HAVE_ARCH_STRNCPY 26 extern char * strncpy(char *,const char *, __kernel_size_t); 27 #endif 28 #ifndef __HAVE_ARCH_STRLCPY 29 size_t strlcpy(char *, const char *, size_t); 30 #endif 31 #ifndef __HAVE_ARCH_STRSCPY 32 ssize_t strscpy(char *, const char *, size_t); 33 #endif 34 35 /* Wraps calls to strscpy()/memset(), no arch specific code required */ 36 ssize_t strscpy_pad(char *dest, const char *src, size_t count); 37 38 #ifndef __HAVE_ARCH_STRCAT 39 extern char * strcat(char *, const char *); 40 #endif 41 #ifndef __HAVE_ARCH_STRNCAT 42 extern char * strncat(char *, const char *, __kernel_size_t); 43 #endif 44 #ifndef __HAVE_ARCH_STRLCAT 45 extern size_t strlcat(char *, const char *, __kernel_size_t); 46 #endif 47 #ifndef __HAVE_ARCH_STRCMP 48 extern int strcmp(const char *,const char *); 49 #endif 50 #ifndef __HAVE_ARCH_STRNCMP 51 extern int strncmp(const char *,const char *,__kernel_size_t); 52 #endif 53 #ifndef __HAVE_ARCH_STRCASECMP 54 extern int strcasecmp(const char *s1, const char *s2); 55 #endif 56 #ifndef __HAVE_ARCH_STRNCASECMP 57 extern int strncasecmp(const char *s1, const char *s2, size_t n); 58 #endif 59 #ifndef __HAVE_ARCH_STRCHR 60 extern char * strchr(const char *,int); 61 #endif 62 #ifndef __HAVE_ARCH_STRCHRNUL 63 extern char * strchrnul(const char *,int); 64 #endif 65 #ifndef __HAVE_ARCH_STRNCHR 66 extern char * strnchr(const char *, size_t, int); 67 #endif 68 #ifndef __HAVE_ARCH_STRRCHR 69 extern char * strrchr(const char *,int); 70 #endif 71 extern char * __must_check skip_spaces(const char *); 72 73 extern char *strim(char *); 74 75 static inline __must_check char *strstrip(char *str) 76 { 77 return strim(str); 78 } 79 80 #ifndef __HAVE_ARCH_STRSTR 81 extern char * strstr(const char *, const char *); 82 #endif 83 #ifndef __HAVE_ARCH_STRNSTR 84 extern char * strnstr(const char *, const char *, size_t); 85 #endif 86 #ifndef __HAVE_ARCH_STRLEN 87 extern __kernel_size_t strlen(const char *); 88 #endif 89 #ifndef __HAVE_ARCH_STRNLEN 90 extern __kernel_size_t strnlen(const char *,__kernel_size_t); 91 #endif 92 #ifndef __HAVE_ARCH_STRPBRK 93 extern char * strpbrk(const char *,const char *); 94 #endif 95 #ifndef __HAVE_ARCH_STRSEP 96 extern char * strsep(char **,const char *); 97 #endif 98 #ifndef __HAVE_ARCH_STRSPN 99 extern __kernel_size_t strspn(const char *,const char *); 100 #endif 101 #ifndef __HAVE_ARCH_STRCSPN 102 extern __kernel_size_t strcspn(const char *,const char *); 103 #endif 104 105 #ifndef __HAVE_ARCH_MEMSET 106 extern void * memset(void *,int,__kernel_size_t); 107 #endif 108 109 #ifndef __HAVE_ARCH_MEMSET16 110 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); 111 #endif 112 113 #ifndef __HAVE_ARCH_MEMSET32 114 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t); 115 #endif 116 117 #ifndef __HAVE_ARCH_MEMSET64 118 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t); 119 #endif 120 121 static inline void *memset_l(unsigned long *p, unsigned long v, 122 __kernel_size_t n) 123 { 124 if (BITS_PER_LONG == 32) 125 return memset32((uint32_t *)p, v, n); 126 else 127 return memset64((uint64_t *)p, v, n); 128 } 129 130 static inline void *memset_p(void **p, void *v, __kernel_size_t n) 131 { 132 if (BITS_PER_LONG == 32) 133 return memset32((uint32_t *)p, (uintptr_t)v, n); 134 else 135 return memset64((uint64_t *)p, (uintptr_t)v, n); 136 } 137 138 extern void **__memcat_p(void **a, void **b); 139 #define memcat_p(a, b) ({ \ 140 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \ 141 "type mismatch in memcat_p()"); \ 142 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \ 143 }) 144 145 #ifndef __HAVE_ARCH_MEMCPY 146 extern void * memcpy(void *,const void *,__kernel_size_t); 147 #endif 148 #ifndef __HAVE_ARCH_MEMMOVE 149 extern void * memmove(void *,const void *,__kernel_size_t); 150 #endif 151 #ifndef __HAVE_ARCH_MEMSCAN 152 extern void * memscan(void *,int,__kernel_size_t); 153 #endif 154 #ifndef __HAVE_ARCH_MEMCMP 155 extern int memcmp(const void *,const void *,__kernel_size_t); 156 #endif 157 #ifndef __HAVE_ARCH_BCMP 158 extern int bcmp(const void *,const void *,__kernel_size_t); 159 #endif 160 #ifndef __HAVE_ARCH_MEMCHR 161 extern void * memchr(const void *,int,__kernel_size_t); 162 #endif 163 #ifndef __HAVE_ARCH_MEMCPY_MCSAFE 164 static inline __must_check unsigned long memcpy_mcsafe(void *dst, 165 const void *src, size_t cnt) 166 { 167 memcpy(dst, src, cnt); 168 return 0; 169 } 170 #endif 171 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE 172 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) 173 { 174 memcpy(dst, src, cnt); 175 } 176 #endif 177 void *memchr_inv(const void *s, int c, size_t n); 178 char *strreplace(char *s, char old, char new); 179 180 extern void kfree_const(const void *x); 181 182 extern char *kstrdup(const char *s, gfp_t gfp) __malloc; 183 extern const char *kstrdup_const(const char *s, gfp_t gfp); 184 extern char *kstrndup(const char *s, size_t len, gfp_t gfp); 185 extern void *kmemdup(const void *src, size_t len, gfp_t gfp); 186 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); 187 188 extern char **argv_split(gfp_t gfp, const char *str, int *argcp); 189 extern void argv_free(char **argv); 190 191 extern bool sysfs_streq(const char *s1, const char *s2); 192 extern int kstrtobool(const char *s, bool *res); 193 static inline int strtobool(const char *s, bool *res) 194 { 195 return kstrtobool(s, res); 196 } 197 198 int match_string(const char * const *array, size_t n, const char *string); 199 int __sysfs_match_string(const char * const *array, size_t n, const char *s); 200 201 /** 202 * sysfs_match_string - matches given string in an array 203 * @_a: array of strings 204 * @_s: string to match with 205 * 206 * Helper for __sysfs_match_string(). Calculates the size of @a automatically. 207 */ 208 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s) 209 210 #ifdef CONFIG_BINARY_PRINTF 211 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); 212 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf); 213 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4); 214 #endif 215 216 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 217 const void *from, size_t available); 218 219 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); 220 221 /** 222 * strstarts - does @str start with @prefix? 223 * @str: string to examine 224 * @prefix: prefix to look for. 225 */ 226 static inline bool strstarts(const char *str, const char *prefix) 227 { 228 return strncmp(str, prefix, strlen(prefix)) == 0; 229 } 230 231 size_t memweight(const void *ptr, size_t bytes); 232 233 /** 234 * memzero_explicit - Fill a region of memory (e.g. sensitive 235 * keying data) with 0s. 236 * @s: Pointer to the start of the area. 237 * @count: The size of the area. 238 * 239 * Note: usually using memset() is just fine (!), but in cases 240 * where clearing out _local_ data at the end of a scope is 241 * necessary, memzero_explicit() should be used instead in 242 * order to prevent the compiler from optimising away zeroing. 243 * 244 * memzero_explicit() doesn't need an arch-specific version as 245 * it just invokes the one of memset() implicitly. 246 */ 247 static inline void memzero_explicit(void *s, size_t count) 248 { 249 memset(s, 0, count); 250 barrier_data(s); 251 } 252 253 /** 254 * kbasename - return the last part of a pathname. 255 * 256 * @path: path to extract the filename from. 257 */ 258 static inline const char *kbasename(const char *path) 259 { 260 const char *tail = strrchr(path, '/'); 261 return tail ? tail + 1 : path; 262 } 263 264 #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline)) 265 #define __RENAME(x) __asm__(#x) 266 267 void fortify_panic(const char *name) __noreturn __cold; 268 void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter"); 269 void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter"); 270 void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter"); 271 void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter"); 272 273 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE) 274 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size) 275 { 276 size_t p_size = __builtin_object_size(p, 0); 277 if (__builtin_constant_p(size) && p_size < size) 278 __write_overflow(); 279 if (p_size < size) 280 fortify_panic(__func__); 281 return __builtin_strncpy(p, q, size); 282 } 283 284 __FORTIFY_INLINE char *strcat(char *p, const char *q) 285 { 286 size_t p_size = __builtin_object_size(p, 0); 287 if (p_size == (size_t)-1) 288 return __builtin_strcat(p, q); 289 if (strlcat(p, q, p_size) >= p_size) 290 fortify_panic(__func__); 291 return p; 292 } 293 294 __FORTIFY_INLINE __kernel_size_t strlen(const char *p) 295 { 296 __kernel_size_t ret; 297 size_t p_size = __builtin_object_size(p, 0); 298 299 /* Work around gcc excess stack consumption issue */ 300 if (p_size == (size_t)-1 || 301 (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0')) 302 return __builtin_strlen(p); 303 ret = strnlen(p, p_size); 304 if (p_size <= ret) 305 fortify_panic(__func__); 306 return ret; 307 } 308 309 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen); 310 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen) 311 { 312 size_t p_size = __builtin_object_size(p, 0); 313 __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size); 314 if (p_size <= ret && maxlen != ret) 315 fortify_panic(__func__); 316 return ret; 317 } 318 319 /* defined after fortified strlen to reuse it */ 320 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy); 321 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size) 322 { 323 size_t ret; 324 size_t p_size = __builtin_object_size(p, 0); 325 size_t q_size = __builtin_object_size(q, 0); 326 if (p_size == (size_t)-1 && q_size == (size_t)-1) 327 return __real_strlcpy(p, q, size); 328 ret = strlen(q); 329 if (size) { 330 size_t len = (ret >= size) ? size - 1 : ret; 331 if (__builtin_constant_p(len) && len >= p_size) 332 __write_overflow(); 333 if (len >= p_size) 334 fortify_panic(__func__); 335 __builtin_memcpy(p, q, len); 336 p[len] = '\0'; 337 } 338 return ret; 339 } 340 341 /* defined after fortified strlen and strnlen to reuse them */ 342 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count) 343 { 344 size_t p_len, copy_len; 345 size_t p_size = __builtin_object_size(p, 0); 346 size_t q_size = __builtin_object_size(q, 0); 347 if (p_size == (size_t)-1 && q_size == (size_t)-1) 348 return __builtin_strncat(p, q, count); 349 p_len = strlen(p); 350 copy_len = strnlen(q, count); 351 if (p_size < p_len + copy_len + 1) 352 fortify_panic(__func__); 353 __builtin_memcpy(p + p_len, q, copy_len); 354 p[p_len + copy_len] = '\0'; 355 return p; 356 } 357 358 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size) 359 { 360 size_t p_size = __builtin_object_size(p, 0); 361 if (__builtin_constant_p(size) && p_size < size) 362 __write_overflow(); 363 if (p_size < size) 364 fortify_panic(__func__); 365 return __builtin_memset(p, c, size); 366 } 367 368 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size) 369 { 370 size_t p_size = __builtin_object_size(p, 0); 371 size_t q_size = __builtin_object_size(q, 0); 372 if (__builtin_constant_p(size)) { 373 if (p_size < size) 374 __write_overflow(); 375 if (q_size < size) 376 __read_overflow2(); 377 } 378 if (p_size < size || q_size < size) 379 fortify_panic(__func__); 380 return __builtin_memcpy(p, q, size); 381 } 382 383 __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size) 384 { 385 size_t p_size = __builtin_object_size(p, 0); 386 size_t q_size = __builtin_object_size(q, 0); 387 if (__builtin_constant_p(size)) { 388 if (p_size < size) 389 __write_overflow(); 390 if (q_size < size) 391 __read_overflow2(); 392 } 393 if (p_size < size || q_size < size) 394 fortify_panic(__func__); 395 return __builtin_memmove(p, q, size); 396 } 397 398 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan); 399 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size) 400 { 401 size_t p_size = __builtin_object_size(p, 0); 402 if (__builtin_constant_p(size) && p_size < size) 403 __read_overflow(); 404 if (p_size < size) 405 fortify_panic(__func__); 406 return __real_memscan(p, c, size); 407 } 408 409 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size) 410 { 411 size_t p_size = __builtin_object_size(p, 0); 412 size_t q_size = __builtin_object_size(q, 0); 413 if (__builtin_constant_p(size)) { 414 if (p_size < size) 415 __read_overflow(); 416 if (q_size < size) 417 __read_overflow2(); 418 } 419 if (p_size < size || q_size < size) 420 fortify_panic(__func__); 421 return __builtin_memcmp(p, q, size); 422 } 423 424 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size) 425 { 426 size_t p_size = __builtin_object_size(p, 0); 427 if (__builtin_constant_p(size) && p_size < size) 428 __read_overflow(); 429 if (p_size < size) 430 fortify_panic(__func__); 431 return __builtin_memchr(p, c, size); 432 } 433 434 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv); 435 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size) 436 { 437 size_t p_size = __builtin_object_size(p, 0); 438 if (__builtin_constant_p(size) && p_size < size) 439 __read_overflow(); 440 if (p_size < size) 441 fortify_panic(__func__); 442 return __real_memchr_inv(p, c, size); 443 } 444 445 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup); 446 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp) 447 { 448 size_t p_size = __builtin_object_size(p, 0); 449 if (__builtin_constant_p(size) && p_size < size) 450 __read_overflow(); 451 if (p_size < size) 452 fortify_panic(__func__); 453 return __real_kmemdup(p, size, gfp); 454 } 455 456 /* defined after fortified strlen and memcpy to reuse them */ 457 __FORTIFY_INLINE char *strcpy(char *p, const char *q) 458 { 459 size_t p_size = __builtin_object_size(p, 0); 460 size_t q_size = __builtin_object_size(q, 0); 461 if (p_size == (size_t)-1 && q_size == (size_t)-1) 462 return __builtin_strcpy(p, q); 463 memcpy(p, q, strlen(q) + 1); 464 return p; 465 } 466 467 #endif 468 469 /** 470 * memcpy_and_pad - Copy one buffer to another with padding 471 * @dest: Where to copy to 472 * @dest_len: The destination buffer size 473 * @src: Where to copy from 474 * @count: The number of bytes to copy 475 * @pad: Character to use for padding if space is left in destination. 476 */ 477 static inline void memcpy_and_pad(void *dest, size_t dest_len, 478 const void *src, size_t count, int pad) 479 { 480 if (dest_len > count) { 481 memcpy(dest, src, count); 482 memset(dest + count, pad, dest_len - count); 483 } else 484 memcpy(dest, src, dest_len); 485 } 486 487 /** 488 * str_has_prefix - Test if a string has a given prefix 489 * @str: The string to test 490 * @prefix: The string to see if @str starts with 491 * 492 * A common way to test a prefix of a string is to do: 493 * strncmp(str, prefix, sizeof(prefix) - 1) 494 * 495 * But this can lead to bugs due to typos, or if prefix is a pointer 496 * and not a constant. Instead use str_has_prefix(). 497 * 498 * Returns: 499 * * strlen(@prefix) if @str starts with @prefix 500 * * 0 if @str does not start with @prefix 501 */ 502 static __always_inline size_t str_has_prefix(const char *str, const char *prefix) 503 { 504 size_t len = strlen(prefix); 505 return strncmp(str, prefix, len) == 0 ? len : 0; 506 } 507 508 #endif /* _LINUX_STRING_H_ */ 509