1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_STRING_H_
3 #define _LINUX_STRING_H_
6 #include <linux/compiler.h> /* for inline */
7 #include <linux/types.h> /* for size_t */
8 #include <linux/stddef.h> /* for NULL */
9 #include <linux/errno.h> /* for E2BIG */
11 #include <uapi/linux/string.h>
13 extern char *strndup_user(const char __user *, long);
14 extern void *memdup_user(const void __user *, size_t);
15 extern void *vmemdup_user(const void __user *, size_t);
16 extern void *memdup_user_nul(const void __user *, size_t);
19 * Include machine specific inline routines
21 #include <asm/string.h>
23 #ifndef __HAVE_ARCH_STRCPY
24 extern char * strcpy(char *,const char *);
26 #ifndef __HAVE_ARCH_STRNCPY
27 extern char * strncpy(char *,const char *, __kernel_size_t);
29 #ifndef __HAVE_ARCH_STRLCPY
30 size_t strlcpy(char *, const char *, size_t);
32 #ifndef __HAVE_ARCH_STRSCPY
33 ssize_t strscpy(char *, const char *, size_t);
36 /* Wraps calls to strscpy()/memset(), no arch specific code required */
37 ssize_t strscpy_pad(char *dest, const char *src, size_t count);
39 #ifndef __HAVE_ARCH_STRCAT
40 extern char * strcat(char *, const char *);
42 #ifndef __HAVE_ARCH_STRNCAT
43 extern char * strncat(char *, const char *, __kernel_size_t);
45 #ifndef __HAVE_ARCH_STRLCAT
46 extern size_t strlcat(char *, const char *, __kernel_size_t);
48 #ifndef __HAVE_ARCH_STRCMP
49 extern int strcmp(const char *,const char *);
51 #ifndef __HAVE_ARCH_STRNCMP
52 extern int strncmp(const char *,const char *,__kernel_size_t);
54 #ifndef __HAVE_ARCH_STRCASECMP
55 extern int strcasecmp(const char *s1, const char *s2);
57 #ifndef __HAVE_ARCH_STRNCASECMP
58 extern int strncasecmp(const char *s1, const char *s2, size_t n);
60 #ifndef __HAVE_ARCH_STRCHR
61 extern char * strchr(const char *,int);
63 #ifndef __HAVE_ARCH_STRCHRNUL
64 extern char * strchrnul(const char *,int);
66 extern char * strnchrnul(const char *, size_t, int);
67 #ifndef __HAVE_ARCH_STRNCHR
68 extern char * strnchr(const char *, size_t, int);
70 #ifndef __HAVE_ARCH_STRRCHR
71 extern char * strrchr(const char *,int);
73 extern char * __must_check skip_spaces(const char *);
75 extern char *strim(char *);
77 static inline __must_check char *strstrip(char *str)
82 #ifndef __HAVE_ARCH_STRSTR
83 extern char * strstr(const char *, const char *);
85 #ifndef __HAVE_ARCH_STRNSTR
86 extern char * strnstr(const char *, const char *, size_t);
88 #ifndef __HAVE_ARCH_STRLEN
89 extern __kernel_size_t strlen(const char *);
91 #ifndef __HAVE_ARCH_STRNLEN
92 extern __kernel_size_t strnlen(const char *,__kernel_size_t);
94 #ifndef __HAVE_ARCH_STRPBRK
95 extern char * strpbrk(const char *,const char *);
97 #ifndef __HAVE_ARCH_STRSEP
98 extern char * strsep(char **,const char *);
100 #ifndef __HAVE_ARCH_STRSPN
101 extern __kernel_size_t strspn(const char *,const char *);
103 #ifndef __HAVE_ARCH_STRCSPN
104 extern __kernel_size_t strcspn(const char *,const char *);
107 #ifndef __HAVE_ARCH_MEMSET
108 extern void * memset(void *,int,__kernel_size_t);
111 #ifndef __HAVE_ARCH_MEMSET16
112 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
115 #ifndef __HAVE_ARCH_MEMSET32
116 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
119 #ifndef __HAVE_ARCH_MEMSET64
120 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
123 static inline void *memset_l(unsigned long *p, unsigned long v,
126 if (BITS_PER_LONG == 32)
127 return memset32((uint32_t *)p, v, n);
129 return memset64((uint64_t *)p, v, n);
132 static inline void *memset_p(void **p, void *v, __kernel_size_t n)
134 if (BITS_PER_LONG == 32)
135 return memset32((uint32_t *)p, (uintptr_t)v, n);
137 return memset64((uint64_t *)p, (uintptr_t)v, n);
140 extern void **__memcat_p(void **a, void **b);
141 #define memcat_p(a, b) ({ \
142 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \
143 "type mismatch in memcat_p()"); \
144 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \
147 #ifndef __HAVE_ARCH_MEMCPY
148 extern void * memcpy(void *,const void *,__kernel_size_t);
150 #ifndef __HAVE_ARCH_MEMMOVE
151 extern void * memmove(void *,const void *,__kernel_size_t);
153 #ifndef __HAVE_ARCH_MEMSCAN
154 extern void * memscan(void *,int,__kernel_size_t);
156 #ifndef __HAVE_ARCH_MEMCMP
157 extern int memcmp(const void *,const void *,__kernel_size_t);
159 #ifndef __HAVE_ARCH_BCMP
160 extern int bcmp(const void *,const void *,__kernel_size_t);
162 #ifndef __HAVE_ARCH_MEMCHR
163 extern void * memchr(const void *,int,__kernel_size_t);
165 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
166 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
168 memcpy(dst, src, cnt);
172 void *memchr_inv(const void *s, int c, size_t n);
173 char *strreplace(char *s, char old, char new);
175 extern void kfree_const(const void *x);
177 extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
178 extern const char *kstrdup_const(const char *s, gfp_t gfp);
179 extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
180 extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
181 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
183 extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
184 extern void argv_free(char **argv);
186 extern bool sysfs_streq(const char *s1, const char *s2);
187 extern int kstrtobool(const char *s, bool *res);
188 static inline int strtobool(const char *s, bool *res)
190 return kstrtobool(s, res);
193 int match_string(const char * const *array, size_t n, const char *string);
194 int __sysfs_match_string(const char * const *array, size_t n, const char *s);
197 * sysfs_match_string - matches given string in an array
198 * @_a: array of strings
199 * @_s: string to match with
201 * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
203 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
205 #ifdef CONFIG_BINARY_PRINTF
206 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
207 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
208 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
211 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
212 const void *from, size_t available);
214 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
217 * strstarts - does @str start with @prefix?
218 * @str: string to examine
219 * @prefix: prefix to look for.
221 static inline bool strstarts(const char *str, const char *prefix)
223 return strncmp(str, prefix, strlen(prefix)) == 0;
226 size_t memweight(const void *ptr, size_t bytes);
229 * memzero_explicit - Fill a region of memory (e.g. sensitive
230 * keying data) with 0s.
231 * @s: Pointer to the start of the area.
232 * @count: The size of the area.
234 * Note: usually using memset() is just fine (!), but in cases
235 * where clearing out _local_ data at the end of a scope is
236 * necessary, memzero_explicit() should be used instead in
237 * order to prevent the compiler from optimising away zeroing.
239 * memzero_explicit() doesn't need an arch-specific version as
240 * it just invokes the one of memset() implicitly.
242 static inline void memzero_explicit(void *s, size_t count)
249 * kbasename - return the last part of a pathname.
251 * @path: path to extract the filename from.
253 static inline const char *kbasename(const char *path)
255 const char *tail = strrchr(path, '/');
256 return tail ? tail + 1 : path;
259 #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
260 #define __RENAME(x) __asm__(#x)
262 void fortify_panic(const char *name) __noreturn __cold;
263 void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
264 void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
265 void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter");
266 void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
268 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
271 extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
272 extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
273 extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
274 extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
275 extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
276 extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat);
277 extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy);
278 extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
279 extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
280 extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
282 #define __underlying_memchr __builtin_memchr
283 #define __underlying_memcmp __builtin_memcmp
284 #define __underlying_memcpy __builtin_memcpy
285 #define __underlying_memmove __builtin_memmove
286 #define __underlying_memset __builtin_memset
287 #define __underlying_strcat __builtin_strcat
288 #define __underlying_strcpy __builtin_strcpy
289 #define __underlying_strlen __builtin_strlen
290 #define __underlying_strncat __builtin_strncat
291 #define __underlying_strncpy __builtin_strncpy
294 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
296 size_t p_size = __builtin_object_size(p, 1);
297 if (__builtin_constant_p(size) && p_size < size)
300 fortify_panic(__func__);
301 return __underlying_strncpy(p, q, size);
304 __FORTIFY_INLINE char *strcat(char *p, const char *q)
306 size_t p_size = __builtin_object_size(p, 1);
307 if (p_size == (size_t)-1)
308 return __underlying_strcat(p, q);
309 if (strlcat(p, q, p_size) >= p_size)
310 fortify_panic(__func__);
314 __FORTIFY_INLINE __kernel_size_t strlen(const char *p)
317 size_t p_size = __builtin_object_size(p, 1);
319 /* Work around gcc excess stack consumption issue */
320 if (p_size == (size_t)-1 ||
321 (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
322 return __underlying_strlen(p);
323 ret = strnlen(p, p_size);
325 fortify_panic(__func__);
329 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
330 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
332 size_t p_size = __builtin_object_size(p, 1);
333 __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
334 if (p_size <= ret && maxlen != ret)
335 fortify_panic(__func__);
339 /* defined after fortified strlen to reuse it */
340 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
341 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
344 size_t p_size = __builtin_object_size(p, 1);
345 size_t q_size = __builtin_object_size(q, 1);
346 if (p_size == (size_t)-1 && q_size == (size_t)-1)
347 return __real_strlcpy(p, q, size);
350 size_t len = (ret >= size) ? size - 1 : ret;
351 if (__builtin_constant_p(len) && len >= p_size)
354 fortify_panic(__func__);
355 __underlying_memcpy(p, q, len);
361 /* defined after fortified strnlen to reuse it */
362 extern ssize_t __real_strscpy(char *, const char *, size_t) __RENAME(strscpy);
363 __FORTIFY_INLINE ssize_t strscpy(char *p, const char *q, size_t size)
366 /* Use string size rather than possible enclosing struct size. */
367 size_t p_size = __builtin_object_size(p, 1);
368 size_t q_size = __builtin_object_size(q, 1);
370 /* If we cannot get size of p and q default to call strscpy. */
371 if (p_size == (size_t) -1 && q_size == (size_t) -1)
372 return __real_strscpy(p, q, size);
375 * If size can be known at compile time and is greater than
376 * p_size, generate a compile time write overflow error.
378 if (__builtin_constant_p(size) && size > p_size)
382 * This call protects from read overflow, because len will default to q
383 * length if it smaller than size.
385 len = strnlen(q, size);
387 * If len equals size, we will copy only size bytes which leads to
388 * -E2BIG being returned.
389 * Otherwise we will copy len + 1 because of the final '\O'.
391 len = len == size ? size : len + 1;
394 * Generate a runtime write overflow error if len is greater than
398 fortify_panic(__func__);
401 * We can now safely call vanilla strscpy because we are protected from:
402 * 1. Read overflow thanks to call to strnlen().
403 * 2. Write overflow thanks to above ifs.
405 return __real_strscpy(p, q, len);
408 /* defined after fortified strlen and strnlen to reuse them */
409 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
411 size_t p_len, copy_len;
412 size_t p_size = __builtin_object_size(p, 1);
413 size_t q_size = __builtin_object_size(q, 1);
414 if (p_size == (size_t)-1 && q_size == (size_t)-1)
415 return __underlying_strncat(p, q, count);
417 copy_len = strnlen(q, count);
418 if (p_size < p_len + copy_len + 1)
419 fortify_panic(__func__);
420 __underlying_memcpy(p + p_len, q, copy_len);
421 p[p_len + copy_len] = '\0';
425 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
427 size_t p_size = __builtin_object_size(p, 0);
428 if (__builtin_constant_p(size) && p_size < size)
431 fortify_panic(__func__);
432 return __underlying_memset(p, c, size);
435 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
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)) {
445 if (p_size < size || q_size < size)
446 fortify_panic(__func__);
447 return __underlying_memcpy(p, q, size);
450 __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
452 size_t p_size = __builtin_object_size(p, 0);
453 size_t q_size = __builtin_object_size(q, 0);
454 if (__builtin_constant_p(size)) {
460 if (p_size < size || q_size < size)
461 fortify_panic(__func__);
462 return __underlying_memmove(p, q, size);
465 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
466 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
468 size_t p_size = __builtin_object_size(p, 0);
469 if (__builtin_constant_p(size) && p_size < size)
472 fortify_panic(__func__);
473 return __real_memscan(p, c, size);
476 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
478 size_t p_size = __builtin_object_size(p, 0);
479 size_t q_size = __builtin_object_size(q, 0);
480 if (__builtin_constant_p(size)) {
486 if (p_size < size || q_size < size)
487 fortify_panic(__func__);
488 return __underlying_memcmp(p, q, size);
491 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
493 size_t p_size = __builtin_object_size(p, 0);
494 if (__builtin_constant_p(size) && p_size < size)
497 fortify_panic(__func__);
498 return __underlying_memchr(p, c, size);
501 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
502 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
504 size_t p_size = __builtin_object_size(p, 0);
505 if (__builtin_constant_p(size) && p_size < size)
508 fortify_panic(__func__);
509 return __real_memchr_inv(p, c, size);
512 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
513 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
515 size_t p_size = __builtin_object_size(p, 0);
516 if (__builtin_constant_p(size) && p_size < size)
519 fortify_panic(__func__);
520 return __real_kmemdup(p, size, gfp);
523 /* defined after fortified strlen and memcpy to reuse them */
524 __FORTIFY_INLINE char *strcpy(char *p, const char *q)
526 size_t p_size = __builtin_object_size(p, 1);
527 size_t q_size = __builtin_object_size(q, 1);
529 if (p_size == (size_t)-1 && q_size == (size_t)-1)
530 return __underlying_strcpy(p, q);
531 size = strlen(q) + 1;
532 /* test here to use the more stringent object size */
534 fortify_panic(__func__);
539 /* Don't use these outside the FORITFY_SOURCE implementation */
540 #undef __underlying_memchr
541 #undef __underlying_memcmp
542 #undef __underlying_memcpy
543 #undef __underlying_memmove
544 #undef __underlying_memset
545 #undef __underlying_strcat
546 #undef __underlying_strcpy
547 #undef __underlying_strlen
548 #undef __underlying_strncat
549 #undef __underlying_strncpy
553 * memcpy_and_pad - Copy one buffer to another with padding
554 * @dest: Where to copy to
555 * @dest_len: The destination buffer size
556 * @src: Where to copy from
557 * @count: The number of bytes to copy
558 * @pad: Character to use for padding if space is left in destination.
560 static inline void memcpy_and_pad(void *dest, size_t dest_len,
561 const void *src, size_t count, int pad)
563 if (dest_len > count) {
564 memcpy(dest, src, count);
565 memset(dest + count, pad, dest_len - count);
567 memcpy(dest, src, dest_len);
571 * str_has_prefix - Test if a string has a given prefix
572 * @str: The string to test
573 * @prefix: The string to see if @str starts with
575 * A common way to test a prefix of a string is to do:
576 * strncmp(str, prefix, sizeof(prefix) - 1)
578 * But this can lead to bugs due to typos, or if prefix is a pointer
579 * and not a constant. Instead use str_has_prefix().
582 * * strlen(@prefix) if @str starts with @prefix
583 * * 0 if @str does not start with @prefix
585 static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
587 size_t len = strlen(prefix);
588 return strncmp(str, prefix, len) == 0 ? len : 0;
591 #endif /* _LINUX_STRING_H_ */