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
strstrip(char * str)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
memset_l(unsigned long * p,unsigned long v,__kernel_size_t n)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
memset_p(void ** p,void * v,__kernel_size_t n)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_FLUSHCACHE
memcpy_flushcache(void * dst,const void * src,size_t cnt)165 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
166 {
167 memcpy(dst, src, cnt);
168 }
169 #endif
170
171 void *memchr_inv(const void *s, int c, size_t n);
172 char *strreplace(char *s, char old, char new);
173
174 extern void kfree_const(const void *x);
175
176 extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
177 extern const char *kstrdup_const(const char *s, gfp_t gfp);
178 extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
179 extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
180 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
181
182 extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
183 extern void argv_free(char **argv);
184
185 extern bool sysfs_streq(const char *s1, const char *s2);
186 extern int kstrtobool(const char *s, bool *res);
strtobool(const char * s,bool * res)187 static inline int strtobool(const char *s, bool *res)
188 {
189 return kstrtobool(s, res);
190 }
191
192 int match_string(const char * const *array, size_t n, const char *string);
193 int __sysfs_match_string(const char * const *array, size_t n, const char *s);
194
195 /**
196 * sysfs_match_string - matches given string in an array
197 * @_a: array of strings
198 * @_s: string to match with
199 *
200 * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
201 */
202 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
203
204 #ifdef CONFIG_BINARY_PRINTF
205 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
206 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
207 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
208 #endif
209
210 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
211 const void *from, size_t available);
212
213 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
214
215 /**
216 * strstarts - does @str start with @prefix?
217 * @str: string to examine
218 * @prefix: prefix to look for.
219 */
strstarts(const char * str,const char * prefix)220 static inline bool strstarts(const char *str, const char *prefix)
221 {
222 return strncmp(str, prefix, strlen(prefix)) == 0;
223 }
224
225 size_t memweight(const void *ptr, size_t bytes);
226
227 /**
228 * memzero_explicit - Fill a region of memory (e.g. sensitive
229 * keying data) with 0s.
230 * @s: Pointer to the start of the area.
231 * @count: The size of the area.
232 *
233 * Note: usually using memset() is just fine (!), but in cases
234 * where clearing out _local_ data at the end of a scope is
235 * necessary, memzero_explicit() should be used instead in
236 * order to prevent the compiler from optimising away zeroing.
237 *
238 * memzero_explicit() doesn't need an arch-specific version as
239 * it just invokes the one of memset() implicitly.
240 */
memzero_explicit(void * s,size_t count)241 static inline void memzero_explicit(void *s, size_t count)
242 {
243 memset(s, 0, count);
244 barrier_data(s);
245 }
246
247 /**
248 * kbasename - return the last part of a pathname.
249 *
250 * @path: path to extract the filename from.
251 */
kbasename(const char * path)252 static inline const char *kbasename(const char *path)
253 {
254 const char *tail = strrchr(path, '/');
255 return tail ? tail + 1 : path;
256 }
257
258 #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
259 #define __RENAME(x) __asm__(#x)
260
261 void fortify_panic(const char *name) __noreturn __cold;
262 void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
263 void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
264 void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter");
265 void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
266
267 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
268
269 #ifdef CONFIG_KASAN
270 extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
271 extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
272 extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
273 extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
274 extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
275 extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat);
276 extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy);
277 extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
278 extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
279 extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
280 #else
281 #define __underlying_memchr __builtin_memchr
282 #define __underlying_memcmp __builtin_memcmp
283 #define __underlying_memcpy __builtin_memcpy
284 #define __underlying_memmove __builtin_memmove
285 #define __underlying_memset __builtin_memset
286 #define __underlying_strcat __builtin_strcat
287 #define __underlying_strcpy __builtin_strcpy
288 #define __underlying_strlen __builtin_strlen
289 #define __underlying_strncat __builtin_strncat
290 #define __underlying_strncpy __builtin_strncpy
291 #endif
292
strncpy(char * p,const char * q,__kernel_size_t size)293 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
294 {
295 size_t p_size = __builtin_object_size(p, 0);
296 if (__builtin_constant_p(size) && p_size < size)
297 __write_overflow();
298 if (p_size < size)
299 fortify_panic(__func__);
300 return __underlying_strncpy(p, q, size);
301 }
302
strcat(char * p,const char * q)303 __FORTIFY_INLINE char *strcat(char *p, const char *q)
304 {
305 size_t p_size = __builtin_object_size(p, 0);
306 if (p_size == (size_t)-1)
307 return __underlying_strcat(p, q);
308 if (strlcat(p, q, p_size) >= p_size)
309 fortify_panic(__func__);
310 return p;
311 }
312
strlen(const char * p)313 __FORTIFY_INLINE __kernel_size_t strlen(const char *p)
314 {
315 __kernel_size_t ret;
316 size_t p_size = __builtin_object_size(p, 0);
317
318 /* Work around gcc excess stack consumption issue */
319 if (p_size == (size_t)-1 ||
320 (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
321 return __underlying_strlen(p);
322 ret = strnlen(p, p_size);
323 if (p_size <= ret)
324 fortify_panic(__func__);
325 return ret;
326 }
327
328 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
strnlen(const char * p,__kernel_size_t maxlen)329 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
330 {
331 size_t p_size = __builtin_object_size(p, 0);
332 __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
333 if (p_size <= ret && maxlen != ret)
334 fortify_panic(__func__);
335 return ret;
336 }
337
338 /* defined after fortified strlen to reuse it */
339 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
strlcpy(char * p,const char * q,size_t size)340 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
341 {
342 size_t ret;
343 size_t p_size = __builtin_object_size(p, 0);
344 size_t q_size = __builtin_object_size(q, 0);
345 if (p_size == (size_t)-1 && q_size == (size_t)-1)
346 return __real_strlcpy(p, q, size);
347 ret = strlen(q);
348 if (size) {
349 size_t len = (ret >= size) ? size - 1 : ret;
350 if (__builtin_constant_p(len) && len >= p_size)
351 __write_overflow();
352 if (len >= p_size)
353 fortify_panic(__func__);
354 __underlying_memcpy(p, q, len);
355 p[len] = '\0';
356 }
357 return ret;
358 }
359
360 /* defined after fortified strlen and strnlen to reuse them */
strncat(char * p,const char * q,__kernel_size_t count)361 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
362 {
363 size_t p_len, copy_len;
364 size_t p_size = __builtin_object_size(p, 0);
365 size_t q_size = __builtin_object_size(q, 0);
366 if (p_size == (size_t)-1 && q_size == (size_t)-1)
367 return __underlying_strncat(p, q, count);
368 p_len = strlen(p);
369 copy_len = strnlen(q, count);
370 if (p_size < p_len + copy_len + 1)
371 fortify_panic(__func__);
372 __underlying_memcpy(p + p_len, q, copy_len);
373 p[p_len + copy_len] = '\0';
374 return p;
375 }
376
memset(void * p,int c,__kernel_size_t size)377 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
378 {
379 size_t p_size = __builtin_object_size(p, 0);
380 if (__builtin_constant_p(size) && p_size < size)
381 __write_overflow();
382 if (p_size < size)
383 fortify_panic(__func__);
384 return __underlying_memset(p, c, size);
385 }
386
memcpy(void * p,const void * q,__kernel_size_t size)387 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
388 {
389 size_t p_size = __builtin_object_size(p, 0);
390 size_t q_size = __builtin_object_size(q, 0);
391 if (__builtin_constant_p(size)) {
392 if (p_size < size)
393 __write_overflow();
394 if (q_size < size)
395 __read_overflow2();
396 }
397 if (p_size < size || q_size < size)
398 fortify_panic(__func__);
399 return __underlying_memcpy(p, q, size);
400 }
401
memmove(void * p,const void * q,__kernel_size_t size)402 __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
403 {
404 size_t p_size = __builtin_object_size(p, 0);
405 size_t q_size = __builtin_object_size(q, 0);
406 if (__builtin_constant_p(size)) {
407 if (p_size < size)
408 __write_overflow();
409 if (q_size < size)
410 __read_overflow2();
411 }
412 if (p_size < size || q_size < size)
413 fortify_panic(__func__);
414 return __underlying_memmove(p, q, size);
415 }
416
417 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
memscan(void * p,int c,__kernel_size_t size)418 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
419 {
420 size_t p_size = __builtin_object_size(p, 0);
421 if (__builtin_constant_p(size) && p_size < size)
422 __read_overflow();
423 if (p_size < size)
424 fortify_panic(__func__);
425 return __real_memscan(p, c, size);
426 }
427
memcmp(const void * p,const void * q,__kernel_size_t size)428 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
429 {
430 size_t p_size = __builtin_object_size(p, 0);
431 size_t q_size = __builtin_object_size(q, 0);
432 if (__builtin_constant_p(size)) {
433 if (p_size < size)
434 __read_overflow();
435 if (q_size < size)
436 __read_overflow2();
437 }
438 if (p_size < size || q_size < size)
439 fortify_panic(__func__);
440 return __underlying_memcmp(p, q, size);
441 }
442
memchr(const void * p,int c,__kernel_size_t size)443 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
444 {
445 size_t p_size = __builtin_object_size(p, 0);
446 if (__builtin_constant_p(size) && p_size < size)
447 __read_overflow();
448 if (p_size < size)
449 fortify_panic(__func__);
450 return __underlying_memchr(p, c, size);
451 }
452
453 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)454 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
455 {
456 size_t p_size = __builtin_object_size(p, 0);
457 if (__builtin_constant_p(size) && p_size < size)
458 __read_overflow();
459 if (p_size < size)
460 fortify_panic(__func__);
461 return __real_memchr_inv(p, c, size);
462 }
463
464 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)465 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
466 {
467 size_t p_size = __builtin_object_size(p, 0);
468 if (__builtin_constant_p(size) && p_size < size)
469 __read_overflow();
470 if (p_size < size)
471 fortify_panic(__func__);
472 return __real_kmemdup(p, size, gfp);
473 }
474
475 /* defined after fortified strlen and memcpy to reuse them */
strcpy(char * p,const char * q)476 __FORTIFY_INLINE char *strcpy(char *p, const char *q)
477 {
478 size_t p_size = __builtin_object_size(p, 0);
479 size_t q_size = __builtin_object_size(q, 0);
480 if (p_size == (size_t)-1 && q_size == (size_t)-1)
481 return __underlying_strcpy(p, q);
482 memcpy(p, q, strlen(q) + 1);
483 return p;
484 }
485
486 /* Don't use these outside the FORITFY_SOURCE implementation */
487 #undef __underlying_memchr
488 #undef __underlying_memcmp
489 #undef __underlying_memcpy
490 #undef __underlying_memmove
491 #undef __underlying_memset
492 #undef __underlying_strcat
493 #undef __underlying_strcpy
494 #undef __underlying_strlen
495 #undef __underlying_strncat
496 #undef __underlying_strncpy
497 #endif
498
499 /**
500 * memcpy_and_pad - Copy one buffer to another with padding
501 * @dest: Where to copy to
502 * @dest_len: The destination buffer size
503 * @src: Where to copy from
504 * @count: The number of bytes to copy
505 * @pad: Character to use for padding if space is left in destination.
506 */
memcpy_and_pad(void * dest,size_t dest_len,const void * src,size_t count,int pad)507 static inline void memcpy_and_pad(void *dest, size_t dest_len,
508 const void *src, size_t count, int pad)
509 {
510 if (dest_len > count) {
511 memcpy(dest, src, count);
512 memset(dest + count, pad, dest_len - count);
513 } else
514 memcpy(dest, src, dest_len);
515 }
516
517 /**
518 * str_has_prefix - Test if a string has a given prefix
519 * @str: The string to test
520 * @prefix: The string to see if @str starts with
521 *
522 * A common way to test a prefix of a string is to do:
523 * strncmp(str, prefix, sizeof(prefix) - 1)
524 *
525 * But this can lead to bugs due to typos, or if prefix is a pointer
526 * and not a constant. Instead use str_has_prefix().
527 *
528 * Returns:
529 * * strlen(@prefix) if @str starts with @prefix
530 * * 0 if @str does not start with @prefix
531 */
str_has_prefix(const char * str,const char * prefix)532 static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
533 {
534 size_t len = strlen(prefix);
535 return strncmp(str, prefix, len) == 0 ? len : 0;
536 }
537
538 #endif /* _LINUX_STRING_H_ */
539
