include/linux/string.h

   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 extern ssize_t memory_read_from_io_buffer(void *to, size_t count, loff_t *ppos,
 219                                           const void *from, size_t available);
 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
 275 #ifdef CONFIG_KASAN
 276 extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
 277 extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
 278 extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
 279 extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
 280 extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
 281 extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat);
 282 extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy);
 283 extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
 284 extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
 285 extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
 286 #else
 287 #define __underlying_memchr     __builtin_memchr
 288 #define __underlying_memcmp     __builtin_memcmp
 289 #define __underlying_memcpy     __builtin_memcpy
 290 #define __underlying_memmove    __builtin_memmove
 291 #define __underlying_memset     __builtin_memset
 292 #define __underlying_strcat     __builtin_strcat
 293 #define __underlying_strcpy     __builtin_strcpy
 294 #define __underlying_strlen     __builtin_strlen
 295 #define __underlying_strncat    __builtin_strncat
 296 #define __underlying_strncpy    __builtin_strncpy
 297 #endif
 298
 299 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
 300 {
 301         size_t p_size = __builtin_object_size(p, 0);
 302         if (__builtin_constant_p(size) && p_size < size)
 303                 __write_overflow();
 304         if (p_size < size)
 305                 fortify_panic(__func__);
 306         return __underlying_strncpy(p, q, size);
 307 }
 308
 309 __FORTIFY_INLINE char *strcat(char *p, const char *q)
 310 {
 311         size_t p_size = __builtin_object_size(p, 0);
 312         if (p_size == (size_t)-1)
 313                 return __underlying_strcat(p, q);
 314         if (strlcat(p, q, p_size) >= p_size)
 315                 fortify_panic(__func__);
 316         return p;
 317 }
 318
 319 __FORTIFY_INLINE __kernel_size_t strlen(const char *p)
 320 {
 321         __kernel_size_t ret;
 322         size_t p_size = __builtin_object_size(p, 0);
 323
 324         /* Work around gcc excess stack consumption issue */
 325         if (p_size == (size_t)-1 ||
 326             (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
 327                 return __underlying_strlen(p);
 328         ret = strnlen(p, p_size);
 329         if (p_size <= ret)
 330                 fortify_panic(__func__);
 331         return ret;
 332 }
 333
 334 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
 335 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
 336 {
 337         size_t p_size = __builtin_object_size(p, 0);
 338         __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
 339         if (p_size <= ret && maxlen != ret)
 340                 fortify_panic(__func__);
 341         return ret;
 342 }
 343
 344 /* defined after fortified strlen to reuse it */
 345 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
 346 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
 347 {
 348         size_t ret;
 349         size_t p_size = __builtin_object_size(p, 0);
 350         size_t q_size = __builtin_object_size(q, 0);
 351         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 352                 return __real_strlcpy(p, q, size);
 353         ret = strlen(q);
 354         if (size) {
 355                 size_t len = (ret >= size) ? size - 1 : ret;
 356                 if (__builtin_constant_p(len) && len >= p_size)
 357                         __write_overflow();
 358                 if (len >= p_size)
 359                         fortify_panic(__func__);
 360                 __underlying_memcpy(p, q, len);
 361                 p[len] = '\0';
 362         }
 363         return ret;
 364 }
 365
 366 /* defined after fortified strlen and strnlen to reuse them */
 367 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
 368 {
 369         size_t p_len, copy_len;
 370         size_t p_size = __builtin_object_size(p, 0);
 371         size_t q_size = __builtin_object_size(q, 0);
 372         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 373                 return __underlying_strncat(p, q, count);
 374         p_len = strlen(p);
 375         copy_len = strnlen(q, count);
 376         if (p_size < p_len + copy_len + 1)
 377                 fortify_panic(__func__);
 378         __underlying_memcpy(p + p_len, q, copy_len);
 379         p[p_len + copy_len] = '\0';
 380         return p;
 381 }
 382
 383 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
 384 {
 385         size_t p_size = __builtin_object_size(p, 0);
 386         if (__builtin_constant_p(size) && p_size < size)
 387                 __write_overflow();
 388         if (p_size < size)
 389                 fortify_panic(__func__);
 390         return __underlying_memset(p, c, size);
 391 }
 392
 393 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
 394 {
 395         size_t p_size = __builtin_object_size(p, 0);
 396         size_t q_size = __builtin_object_size(q, 0);
 397         if (__builtin_constant_p(size)) {
 398                 if (p_size < size)
 399                         __write_overflow();
 400                 if (q_size < size)
 401                         __read_overflow2();
 402         }
 403         if (p_size < size || q_size < size)
 404                 fortify_panic(__func__);
 405         return __underlying_memcpy(p, q, size);
 406 }
 407
 408 __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
 409 {
 410         size_t p_size = __builtin_object_size(p, 0);
 411         size_t q_size = __builtin_object_size(q, 0);
 412         if (__builtin_constant_p(size)) {
 413                 if (p_size < size)
 414                         __write_overflow();
 415                 if (q_size < size)
 416                         __read_overflow2();
 417         }
 418         if (p_size < size || q_size < size)
 419                 fortify_panic(__func__);
 420         return __underlying_memmove(p, q, size);
 421 }
 422
 423 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
 424 __FORTIFY_INLINE void *memscan(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 __real_memscan(p, c, size);
 432 }
 433
 434 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
 435 {
 436         size_t p_size = __builtin_object_size(p, 0);
 437         size_t q_size = __builtin_object_size(q, 0);
 438         if (__builtin_constant_p(size)) {
 439                 if (p_size < size)
 440                         __read_overflow();
 441                 if (q_size < size)
 442                         __read_overflow2();
 443         }
 444         if (p_size < size || q_size < size)
 445                 fortify_panic(__func__);
 446         return __underlying_memcmp(p, q, size);
 447 }
 448
 449 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
 450 {
 451         size_t p_size = __builtin_object_size(p, 0);
 452         if (__builtin_constant_p(size) && p_size < size)
 453                 __read_overflow();
 454         if (p_size < size)
 455                 fortify_panic(__func__);
 456         return __underlying_memchr(p, c, size);
 457 }
 458
 459 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
 460 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
 461 {
 462         size_t p_size = __builtin_object_size(p, 0);
 463         if (__builtin_constant_p(size) && p_size < size)
 464                 __read_overflow();
 465         if (p_size < size)
 466                 fortify_panic(__func__);
 467         return __real_memchr_inv(p, c, size);
 468 }
 469
 470 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
 471 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
 472 {
 473         size_t p_size = __builtin_object_size(p, 0);
 474         if (__builtin_constant_p(size) && p_size < size)
 475                 __read_overflow();
 476         if (p_size < size)
 477                 fortify_panic(__func__);
 478         return __real_kmemdup(p, size, gfp);
 479 }
 480
 481 /* defined after fortified strlen and memcpy to reuse them */
 482 __FORTIFY_INLINE char *strcpy(char *p, const char *q)
 483 {
 484         size_t p_size = __builtin_object_size(p, 0);
 485         size_t q_size = __builtin_object_size(q, 0);
 486         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 487                 return __underlying_strcpy(p, q);
 488         memcpy(p, q, strlen(q) + 1);
 489         return p;
 490 }
 491
 492 /* Don't use these outside the FORITFY_SOURCE implementation */
 493 #undef __underlying_memchr
 494 #undef __underlying_memcmp
 495 #undef __underlying_memcpy
 496 #undef __underlying_memmove
 497 #undef __underlying_memset
 498 #undef __underlying_strcat
 499 #undef __underlying_strcpy
 500 #undef __underlying_strlen
 501 #undef __underlying_strncat
 502 #undef __underlying_strncpy
 503 #endif
 504
 505 /**
 506  * memcpy_and_pad - Copy one buffer to another with padding
 507  * @dest: Where to copy to
 508  * @dest_len: The destination buffer size
 509  * @src: Where to copy from
 510  * @count: The number of bytes to copy
 511  * @pad: Character to use for padding if space is left in destination.
 512  */
 513 static inline void memcpy_and_pad(void *dest, size_t dest_len,
 514                                   const void *src, size_t count, int pad)
 515 {
 516         if (dest_len > count) {
 517                 memcpy(dest, src, count);
 518                 memset(dest + count, pad,  dest_len - count);
 519         } else
 520                 memcpy(dest, src, dest_len);
 521 }
 522
 523 /**
 524  * str_has_prefix - Test if a string has a given prefix
 525  * @str: The string to test
 526  * @prefix: The string to see if @str starts with
 527  *
 528  * A common way to test a prefix of a string is to do:
 529  *  strncmp(str, prefix, sizeof(prefix) - 1)
 530  *
 531  * But this can lead to bugs due to typos, or if prefix is a pointer
 532  * and not a constant. Instead use str_has_prefix().
 533  *
 534  * Returns:
 535  * * strlen(@prefix) if @str starts with @prefix
 536  * * 0 if @str does not start with @prefix
 537  */
 538 static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
 539 {
 540         size_t len = strlen(prefix);
 541         return strncmp(str, prefix, len) == 0 ? len : 0;
 542 }
 543
 544 #endif /* _LINUX_STRING_H_ */