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