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
strstrip(char * str)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
memset_l(unsigned long * p,unsigned long v,__kernel_size_t n)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
memset_p(void ** p,void * v,__kernel_size_t n)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
memcpy_mcsafe(void * dst,const void * src,size_t cnt)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
memcpy_flushcache(void * dst,const void * src,size_t cnt)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);
strtobool(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 */
strstarts(const char * str,const char * prefix)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 */
memzero_explicit(void * s,size_t count)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 */
kbasename(const char * path)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
strncpy(char * p,const char * q,__kernel_size_t size)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
strcat(char * p,const char * q)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
strlen(const char * p)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);
strnlen(const char * p,__kernel_size_t maxlen)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);
strlcpy(char * p,const char * q,size_t size)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 */
strncat(char * p,const char * q,__kernel_size_t count)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
memset(void * p,int c,__kernel_size_t size)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
memcpy(void * p,const void * q,__kernel_size_t size)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
memmove(void * p,const void * q,__kernel_size_t size)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);
memscan(void * p,int c,__kernel_size_t size)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
memcmp(const void * p,const void * q,__kernel_size_t size)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
memchr(const void * p,int c,__kernel_size_t size)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);
memchr_inv(const void * p,int c,size_t size)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);
kmemdup(const void * p,size_t size,gfp_t gfp)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 */
strcpy(char * p,const char * q)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 */
memcpy_and_pad(void * dest,size_t dest_len,const void * src,size_t count,int pad)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 */
str_has_prefix(const char * str,const char * prefix)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_ */
545