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 extern char * strnchrnul(const char *, size_t, int); 66 #ifndef __HAVE_ARCH_STRNCHR 67 extern char * strnchr(const char *, size_t, int); 68 #endif 69 #ifndef __HAVE_ARCH_STRRCHR 70 extern char * strrchr(const char *,int); 71 #endif 72 extern char * __must_check skip_spaces(const char *); 73 74 extern char *strim(char *); 75 76 static inline __must_check char *strstrip(char *str) 77 { 78 return strim(str); 79 } 80 81 #ifndef __HAVE_ARCH_STRSTR 82 extern char * strstr(const char *, const char *); 83 #endif 84 #ifndef __HAVE_ARCH_STRNSTR 85 extern char * strnstr(const char *, const char *, size_t); 86 #endif 87 #ifndef __HAVE_ARCH_STRLEN 88 extern __kernel_size_t strlen(const char *); 89 #endif 90 #ifndef __HAVE_ARCH_STRNLEN 91 extern __kernel_size_t strnlen(const char *,__kernel_size_t); 92 #endif 93 #ifndef __HAVE_ARCH_STRPBRK 94 extern char * strpbrk(const char *,const char *); 95 #endif 96 #ifndef __HAVE_ARCH_STRSEP 97 extern char * strsep(char **,const char *); 98 #endif 99 #ifndef __HAVE_ARCH_STRSPN 100 extern __kernel_size_t strspn(const char *,const char *); 101 #endif 102 #ifndef __HAVE_ARCH_STRCSPN 103 extern __kernel_size_t strcspn(const char *,const char *); 104 #endif 105 106 #ifndef __HAVE_ARCH_MEMSET 107 extern void * memset(void *,int,__kernel_size_t); 108 #endif 109 110 #ifndef __HAVE_ARCH_MEMSET16 111 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); 112 #endif 113 114 #ifndef __HAVE_ARCH_MEMSET32 115 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t); 116 #endif 117 118 #ifndef __HAVE_ARCH_MEMSET64 119 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t); 120 #endif 121 122 static inline void *memset_l(unsigned long *p, unsigned long v, 123 __kernel_size_t n) 124 { 125 if (BITS_PER_LONG == 32) 126 return memset32((uint32_t *)p, v, n); 127 else 128 return memset64((uint64_t *)p, v, n); 129 } 130 131 static inline void *memset_p(void **p, void *v, __kernel_size_t n) 132 { 133 if (BITS_PER_LONG == 32) 134 return memset32((uint32_t *)p, (uintptr_t)v, n); 135 else 136 return memset64((uint64_t *)p, (uintptr_t)v, n); 137 } 138 139 extern void **__memcat_p(void **a, void **b); 140 #define memcat_p(a, b) ({ \ 141 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \ 142 "type mismatch in memcat_p()"); \ 143 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \ 144 }) 145 146 #ifndef __HAVE_ARCH_MEMCPY 147 extern void * memcpy(void *,const void *,__kernel_size_t); 148 #endif 149 #ifndef __HAVE_ARCH_MEMMOVE 150 extern void * memmove(void *,const void *,__kernel_size_t); 151 #endif 152 #ifndef __HAVE_ARCH_MEMSCAN 153 extern void * memscan(void *,int,__kernel_size_t); 154 #endif 155 #ifndef __HAVE_ARCH_MEMCMP 156 extern int memcmp(const void *,const void *,__kernel_size_t); 157 #endif 158 #ifndef __HAVE_ARCH_BCMP 159 extern int bcmp(const void *,const void *,__kernel_size_t); 160 #endif 161 #ifndef __HAVE_ARCH_MEMCHR 162 extern void * memchr(const void *,int,__kernel_size_t); 163 #endif 164 #ifndef __HAVE_ARCH_MEMCPY_MCSAFE 165 static inline __must_check unsigned long memcpy_mcsafe(void *dst, 166 const void *src, size_t cnt) 167 { 168 memcpy(dst, src, cnt); 169 return 0; 170 } 171 #endif 172 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE 173 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) 174 { 175 memcpy(dst, src, cnt); 176 } 177 #endif 178 void *memchr_inv(const void *s, int c, size_t n); 179 char *strreplace(char *s, char old, char new); 180 181 extern void kfree_const(const void *x); 182 183 extern char *kstrdup(const char *s, gfp_t gfp) __malloc; 184 extern const char *kstrdup_const(const char *s, gfp_t gfp); 185 extern char *kstrndup(const char *s, size_t len, gfp_t gfp); 186 extern void *kmemdup(const void *src, size_t len, gfp_t gfp); 187 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); 188 189 extern char **argv_split(gfp_t gfp, const char *str, int *argcp); 190 extern void argv_free(char **argv); 191 192 extern bool sysfs_streq(const char *s1, const char *s2); 193 extern int kstrtobool(const char *s, bool *res); 194 static inline int strtobool(const char *s, bool *res) 195 { 196 return kstrtobool(s, res); 197 } 198 199 int match_string(const char * const *array, size_t n, const char *string); 200 int __sysfs_match_string(const char * const *array, size_t n, const char *s); 201 202 /** 203 * sysfs_match_string - matches given string in an array 204 * @_a: array of strings 205 * @_s: string to match with 206 * 207 * Helper for __sysfs_match_string(). Calculates the size of @a automatically. 208 */ 209 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s) 210 211 #ifdef CONFIG_BINARY_PRINTF 212 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); 213 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf); 214 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4); 215 #endif 216 217 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 218 const void *from, size_t available); 219 220 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); 221 222 /** 223 * strstarts - does @str start with @prefix? 224 * @str: string to examine 225 * @prefix: prefix to look for. 226 */ 227 static inline bool strstarts(const char *str, const char *prefix) 228 { 229 return strncmp(str, prefix, strlen(prefix)) == 0; 230 } 231 232 size_t memweight(const void *ptr, size_t bytes); 233 234 /** 235 * memzero_explicit - Fill a region of memory (e.g. sensitive 236 * keying data) with 0s. 237 * @s: Pointer to the start of the area. 238 * @count: The size of the area. 239 * 240 * Note: usually using memset() is just fine (!), but in cases 241 * where clearing out _local_ data at the end of a scope is 242 * necessary, memzero_explicit() should be used instead in 243 * order to prevent the compiler from optimising away zeroing. 244 * 245 * memzero_explicit() doesn't need an arch-specific version as 246 * it just invokes the one of memset() implicitly. 247 */ 248 static inline void memzero_explicit(void *s, size_t count) 249 { 250 memset(s, 0, count); 251 barrier_data(s); 252 } 253 254 /** 255 * kbasename - return the last part of a pathname. 256 * 257 * @path: path to extract the filename from. 258 */ 259 static inline const char *kbasename(const char *path) 260 { 261 const char *tail = strrchr(path, '/'); 262 return tail ? tail + 1 : path; 263 } 264 265 #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline)) 266 #define __RENAME(x) __asm__(#x) 267 268 void fortify_panic(const char *name) __noreturn __cold; 269 void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter"); 270 void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter"); 271 void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter"); 272 void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter"); 273 274 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE) 275 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size) 276 { 277 size_t p_size = __builtin_object_size(p, 0); 278 if (__builtin_constant_p(size) && p_size < size) 279 __write_overflow(); 280 if (p_size < size) 281 fortify_panic(__func__); 282 return __builtin_strncpy(p, q, size); 283 } 284 285 __FORTIFY_INLINE char *strcat(char *p, const char *q) 286 { 287 size_t p_size = __builtin_object_size(p, 0); 288 if (p_size == (size_t)-1) 289 return __builtin_strcat(p, q); 290 if (strlcat(p, q, p_size) >= p_size) 291 fortify_panic(__func__); 292 return p; 293 } 294 295 __FORTIFY_INLINE __kernel_size_t strlen(const char *p) 296 { 297 __kernel_size_t ret; 298 size_t p_size = __builtin_object_size(p, 0); 299 300 /* Work around gcc excess stack consumption issue */ 301 if (p_size == (size_t)-1 || 302 (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0')) 303 return __builtin_strlen(p); 304 ret = strnlen(p, p_size); 305 if (p_size <= ret) 306 fortify_panic(__func__); 307 return ret; 308 } 309 310 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen); 311 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen) 312 { 313 size_t p_size = __builtin_object_size(p, 0); 314 __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size); 315 if (p_size <= ret && maxlen != ret) 316 fortify_panic(__func__); 317 return ret; 318 } 319 320 /* defined after fortified strlen to reuse it */ 321 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy); 322 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size) 323 { 324 size_t ret; 325 size_t p_size = __builtin_object_size(p, 0); 326 size_t q_size = __builtin_object_size(q, 0); 327 if (p_size == (size_t)-1 && q_size == (size_t)-1) 328 return __real_strlcpy(p, q, size); 329 ret = strlen(q); 330 if (size) { 331 size_t len = (ret >= size) ? size - 1 : ret; 332 if (__builtin_constant_p(len) && len >= p_size) 333 __write_overflow(); 334 if (len >= p_size) 335 fortify_panic(__func__); 336 __builtin_memcpy(p, q, len); 337 p[len] = '\0'; 338 } 339 return ret; 340 } 341 342 /* defined after fortified strlen and strnlen to reuse them */ 343 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count) 344 { 345 size_t p_len, copy_len; 346 size_t p_size = __builtin_object_size(p, 0); 347 size_t q_size = __builtin_object_size(q, 0); 348 if (p_size == (size_t)-1 && q_size == (size_t)-1) 349 return __builtin_strncat(p, q, count); 350 p_len = strlen(p); 351 copy_len = strnlen(q, count); 352 if (p_size < p_len + copy_len + 1) 353 fortify_panic(__func__); 354 __builtin_memcpy(p + p_len, q, copy_len); 355 p[p_len + copy_len] = '\0'; 356 return p; 357 } 358 359 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size) 360 { 361 size_t p_size = __builtin_object_size(p, 0); 362 if (__builtin_constant_p(size) && p_size < size) 363 __write_overflow(); 364 if (p_size < size) 365 fortify_panic(__func__); 366 return __builtin_memset(p, c, size); 367 } 368 369 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size) 370 { 371 size_t p_size = __builtin_object_size(p, 0); 372 size_t q_size = __builtin_object_size(q, 0); 373 if (__builtin_constant_p(size)) { 374 if (p_size < size) 375 __write_overflow(); 376 if (q_size < size) 377 __read_overflow2(); 378 } 379 if (p_size < size || q_size < size) 380 fortify_panic(__func__); 381 return __builtin_memcpy(p, q, size); 382 } 383 384 __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size) 385 { 386 size_t p_size = __builtin_object_size(p, 0); 387 size_t q_size = __builtin_object_size(q, 0); 388 if (__builtin_constant_p(size)) { 389 if (p_size < size) 390 __write_overflow(); 391 if (q_size < size) 392 __read_overflow2(); 393 } 394 if (p_size < size || q_size < size) 395 fortify_panic(__func__); 396 return __builtin_memmove(p, q, size); 397 } 398 399 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan); 400 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size) 401 { 402 size_t p_size = __builtin_object_size(p, 0); 403 if (__builtin_constant_p(size) && p_size < size) 404 __read_overflow(); 405 if (p_size < size) 406 fortify_panic(__func__); 407 return __real_memscan(p, c, size); 408 } 409 410 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size) 411 { 412 size_t p_size = __builtin_object_size(p, 0); 413 size_t q_size = __builtin_object_size(q, 0); 414 if (__builtin_constant_p(size)) { 415 if (p_size < size) 416 __read_overflow(); 417 if (q_size < size) 418 __read_overflow2(); 419 } 420 if (p_size < size || q_size < size) 421 fortify_panic(__func__); 422 return __builtin_memcmp(p, q, size); 423 } 424 425 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size) 426 { 427 size_t p_size = __builtin_object_size(p, 0); 428 if (__builtin_constant_p(size) && p_size < size) 429 __read_overflow(); 430 if (p_size < size) 431 fortify_panic(__func__); 432 return __builtin_memchr(p, c, size); 433 } 434 435 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv); 436 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size) 437 { 438 size_t p_size = __builtin_object_size(p, 0); 439 if (__builtin_constant_p(size) && p_size < size) 440 __read_overflow(); 441 if (p_size < size) 442 fortify_panic(__func__); 443 return __real_memchr_inv(p, c, size); 444 } 445 446 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup); 447 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp) 448 { 449 size_t p_size = __builtin_object_size(p, 0); 450 if (__builtin_constant_p(size) && p_size < size) 451 __read_overflow(); 452 if (p_size < size) 453 fortify_panic(__func__); 454 return __real_kmemdup(p, size, gfp); 455 } 456 457 /* defined after fortified strlen and memcpy to reuse them */ 458 __FORTIFY_INLINE char *strcpy(char *p, const char *q) 459 { 460 size_t p_size = __builtin_object_size(p, 0); 461 size_t q_size = __builtin_object_size(q, 0); 462 if (p_size == (size_t)-1 && q_size == (size_t)-1) 463 return __builtin_strcpy(p, q); 464 memcpy(p, q, strlen(q) + 1); 465 return p; 466 } 467 468 #endif 469 470 /** 471 * memcpy_and_pad - Copy one buffer to another with padding 472 * @dest: Where to copy to 473 * @dest_len: The destination buffer size 474 * @src: Where to copy from 475 * @count: The number of bytes to copy 476 * @pad: Character to use for padding if space is left in destination. 477 */ 478 static inline void memcpy_and_pad(void *dest, size_t dest_len, 479 const void *src, size_t count, int pad) 480 { 481 if (dest_len > count) { 482 memcpy(dest, src, count); 483 memset(dest + count, pad, dest_len - count); 484 } else 485 memcpy(dest, src, dest_len); 486 } 487 488 /** 489 * str_has_prefix - Test if a string has a given prefix 490 * @str: The string to test 491 * @prefix: The string to see if @str starts with 492 * 493 * A common way to test a prefix of a string is to do: 494 * strncmp(str, prefix, sizeof(prefix) - 1) 495 * 496 * But this can lead to bugs due to typos, or if prefix is a pointer 497 * and not a constant. Instead use str_has_prefix(). 498 * 499 * Returns: 500 * * strlen(@prefix) if @str starts with @prefix 501 * * 0 if @str does not start with @prefix 502 */ 503 static __always_inline size_t str_has_prefix(const char *str, const char *prefix) 504 { 505 size_t len = strlen(prefix); 506 return strncmp(str, prefix, len) == 0 ? len : 0; 507 } 508 509 #endif /* _LINUX_STRING_H_ */ 510