[linux-block.git] / include / linux / fortify-string.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FORTIFY_STRING_H_
#define _LINUX_FORTIFY_STRING_H_

#define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
#define __RENAME(x) __asm__(#x)

void fortify_panic(const char *name) __noreturn __cold;
void __read_overflow(void) __compiletime_error("detected read beyond size of object (1st parameter)");
void __read_overflow2(void) __compiletime_error("detected read beyond size of object (2nd parameter)");
void __write_overflow(void) __compiletime_error("detected write beyond size of object (1st parameter)");

#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat);
extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy);
extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
#else
#define __underlying_memchr	__builtin_memchr
#define __underlying_memcmp	__builtin_memcmp
#define __underlying_memcpy	__builtin_memcpy
#define __underlying_memmove	__builtin_memmove
#define __underlying_memset	__builtin_memset
#define __underlying_strcat	__builtin_strcat
#define __underlying_strcpy	__builtin_strcpy
#define __underlying_strlen	__builtin_strlen
#define __underlying_strncat	__builtin_strncat
#define __underlying_strncpy	__builtin_strncpy
#endif

__FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
{
	size_t p_size = __builtin_object_size(p, 1);

	if (__builtin_constant_p(size) && p_size < size)
		__write_overflow();
	if (p_size < size)
		fortify_panic(__func__);
	return __underlying_strncpy(p, q, size);
}

__FORTIFY_INLINE char *strcat(char *p, const char *q)
{
	size_t p_size = __builtin_object_size(p, 1);

	if (p_size == (size_t)-1)
		return __underlying_strcat(p, q);
	if (strlcat(p, q, p_size) >= p_size)
		fortify_panic(__func__);
	return p;
}

extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
__FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
{
	size_t p_size = __builtin_object_size(p, 1);
	__kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);

	if (p_size <= ret && maxlen != ret)
		fortify_panic(__func__);
	return ret;
}

__FORTIFY_INLINE __kernel_size_t strlen(const char *p)
{
	__kernel_size_t ret;
	size_t p_size = __builtin_object_size(p, 1);

	/* Work around gcc excess stack consumption issue */
	if (p_size == (size_t)-1 ||
		(__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
		return __underlying_strlen(p);
	ret = strnlen(p, p_size);
	if (p_size <= ret)
		fortify_panic(__func__);
	return ret;
}

/* defined after fortified strlen to reuse it */
extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
__FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
{
	size_t ret;
	size_t p_size = __builtin_object_size(p, 1);
	size_t q_size = __builtin_object_size(q, 1);

	if (p_size == (size_t)-1 && q_size == (size_t)-1)
		return __real_strlcpy(p, q, size);
	ret = strlen(q);
	if (size) {
		size_t len = (ret >= size) ? size - 1 : ret;

		if (__builtin_constant_p(len) && len >= p_size)
			__write_overflow();
		if (len >= p_size)
			fortify_panic(__func__);
		__underlying_memcpy(p, q, len);
		p[len] = '\0';
	}
	return ret;
}

/* defined after fortified strnlen to reuse it */
extern ssize_t __real_strscpy(char *, const char *, size_t) __RENAME(strscpy);
__FORTIFY_INLINE ssize_t strscpy(char *p, const char *q, size_t size)
{
	size_t len;
	/* Use string size rather than possible enclosing struct size. */
	size_t p_size = __builtin_object_size(p, 1);
	size_t q_size = __builtin_object_size(q, 1);

	/* If we cannot get size of p and q default to call strscpy. */
	if (p_size == (size_t) -1 && q_size == (size_t) -1)
		return __real_strscpy(p, q, size);

	/*
	 * If size can be known at compile time and is greater than
	 * p_size, generate a compile time write overflow error.
	 */
	if (__builtin_constant_p(size) && size > p_size)
		__write_overflow();

	/*
	 * This call protects from read overflow, because len will default to q
	 * length if it smaller than size.
	 */
	len = strnlen(q, size);
	/*
	 * If len equals size, we will copy only size bytes which leads to
	 * -E2BIG being returned.
	 * Otherwise we will copy len + 1 because of the final '\O'.
	 */
	len = len == size ? size : len + 1;

	/*
	 * Generate a runtime write overflow error if len is greater than
	 * p_size.
	 */
	if (len > p_size)
		fortify_panic(__func__);

	/*
	 * We can now safely call vanilla strscpy because we are protected from:
	 * 1. Read overflow thanks to call to strnlen().
	 * 2. Write overflow thanks to above ifs.
	 */
	return __real_strscpy(p, q, len);
}

/* defined after fortified strlen and strnlen to reuse them */
__FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
{
	size_t p_len, copy_len;
	size_t p_size = __builtin_object_size(p, 1);
	size_t q_size = __builtin_object_size(q, 1);

	if (p_size == (size_t)-1 && q_size == (size_t)-1)
		return __underlying_strncat(p, q, count);
	p_len = strlen(p);
	copy_len = strnlen(q, count);
	if (p_size < p_len + copy_len + 1)
		fortify_panic(__func__);
	__underlying_memcpy(p + p_len, q, copy_len);
	p[p_len + copy_len] = '\0';
	return p;
}

__FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
{
	size_t p_size = __builtin_object_size(p, 0);

	if (__builtin_constant_p(size) && p_size < size)
		__write_overflow();
	if (p_size < size)
		fortify_panic(__func__);
	return __underlying_memset(p, c, size);
}

__FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
{
	size_t p_size = __builtin_object_size(p, 0);
	size_t q_size = __builtin_object_size(q, 0);

	if (__builtin_constant_p(size)) {
		if (p_size < size)
			__write_overflow();
		if (q_size < size)
			__read_overflow2();
	}
	if (p_size < size || q_size < size)
		fortify_panic(__func__);
	return __underlying_memcpy(p, q, size);
}

__FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
{
	size_t p_size = __builtin_object_size(p, 0);
	size_t q_size = __builtin_object_size(q, 0);

	if (__builtin_constant_p(size)) {
		if (p_size < size)
			__write_overflow();
		if (q_size < size)
			__read_overflow2();
	}
	if (p_size < size || q_size < size)
		fortify_panic(__func__);
	return __underlying_memmove(p, q, size);
}

extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
__FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
{
	size_t p_size = __builtin_object_size(p, 0);

	if (__builtin_constant_p(size) && p_size < size)
		__read_overflow();
	if (p_size < size)
		fortify_panic(__func__);
	return __real_memscan(p, c, size);
}

__FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
{
	size_t p_size = __builtin_object_size(p, 0);
	size_t q_size = __builtin_object_size(q, 0);

	if (__builtin_constant_p(size)) {
		if (p_size < size)
			__read_overflow();
		if (q_size < size)
			__read_overflow2();
	}
	if (p_size < size || q_size < size)
		fortify_panic(__func__);
	return __underlying_memcmp(p, q, size);
}

__FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
{
	size_t p_size = __builtin_object_size(p, 0);

	if (__builtin_constant_p(size) && p_size < size)
		__read_overflow();
	if (p_size < size)
		fortify_panic(__func__);
	return __underlying_memchr(p, c, size);
}

void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
__FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
{
	size_t p_size = __builtin_object_size(p, 0);

	if (__builtin_constant_p(size) && p_size < size)
		__read_overflow();
	if (p_size < size)
		fortify_panic(__func__);
	return __real_memchr_inv(p, c, size);
}

extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
__FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
{
	size_t p_size = __builtin_object_size(p, 0);

	if (__builtin_constant_p(size) && p_size < size)
		__read_overflow();
	if (p_size < size)
		fortify_panic(__func__);
	return __real_kmemdup(p, size, gfp);
}

/* defined after fortified strlen and memcpy to reuse them */
__FORTIFY_INLINE char *strcpy(char *p, const char *q)
{
	size_t p_size = __builtin_object_size(p, 1);
	size_t q_size = __builtin_object_size(q, 1);
	size_t size;

	if (p_size == (size_t)-1 && q_size == (size_t)-1)
		return __underlying_strcpy(p, q);
	size = strlen(q) + 1;
	/* Compile-time check for const size overflow. */
	if (__builtin_constant_p(size) && p_size < size)
		__write_overflow();
	/* Run-time check for dynamic size overflow. */
	if (p_size < size)
		fortify_panic(__func__);
	memcpy(p, q, size);
	return p;
}

/* Don't use these outside the FORITFY_SOURCE implementation */
#undef __underlying_memchr
#undef __underlying_memcmp
#undef __underlying_memcpy
#undef __underlying_memmove
#undef __underlying_memset
#undef __underlying_strcat
#undef __underlying_strcpy
#undef __underlying_strlen
#undef __underlying_strncat
#undef __underlying_strncpy

#endif /* _LINUX_FORTIFY_STRING_H_ */
Commit	Line	Data
a28a6e86 FL	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#ifndef _LINUX_FORTIFY_STRING_H_
	3	#define _LINUX_FORTIFY_STRING_H_
	4
c430f600 KC	5	#define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
	6	#define __RENAME(x) __asm__(#x)
	7
	8	void fortify_panic(const char *name) __noreturn __cold;
	9	void __read_overflow(void) __compiletime_error("detected read beyond size of object (1st parameter)");
	10	void __read_overflow2(void) __compiletime_error("detected read beyond size of object (2nd parameter)");
	11	void __write_overflow(void) __compiletime_error("detected write beyond size of object (1st parameter)");
a28a6e86 FL	12
	13	#if defined(CONFIG_KASAN_GENERIC) \|\| defined(CONFIG_KASAN_SW_TAGS)
	14	extern void __underlying_memchr(const void p, int c, __kernel_size_t size) __RENAME(memchr);
	15	extern int __underlying_memcmp(const void p, const void q, __kernel_size_t size) __RENAME(memcmp);
	16	extern void __underlying_memcpy(void p, const void *q, __kernel_size_t size) __RENAME(memcpy);
	17	extern void __underlying_memmove(void p, const void *q, __kernel_size_t size) __RENAME(memmove);
	18	extern void __underlying_memset(void p, int c, __kernel_size_t size) __RENAME(memset);
	19	extern char __underlying_strcat(char p, const char *q) __RENAME(strcat);
	20	extern char __underlying_strcpy(char p, const char *q) __RENAME(strcpy);
	21	extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
	22	extern char __underlying_strncat(char p, const char *q, __kernel_size_t count) __RENAME(strncat);
	23	extern char __underlying_strncpy(char p, const char *q, __kernel_size_t size) __RENAME(strncpy);
	24	#else
	25	#define __underlying_memchr __builtin_memchr
	26	#define __underlying_memcmp __builtin_memcmp
	27	#define __underlying_memcpy __builtin_memcpy
	28	#define __underlying_memmove __builtin_memmove
	29	#define __underlying_memset __builtin_memset
	30	#define __underlying_strcat __builtin_strcat
	31	#define __underlying_strcpy __builtin_strcpy
	32	#define __underlying_strlen __builtin_strlen
	33	#define __underlying_strncat __builtin_strncat
	34	#define __underlying_strncpy __builtin_strncpy
	35	#endif
	36
	37	__FORTIFY_INLINE char strncpy(char p, const char *q, __kernel_size_t size)
	38	{
	39	size_t p_size = __builtin_object_size(p, 1);
	40
	41	if (__builtin_constant_p(size) && p_size < size)
	42	__write_overflow();
	43	if (p_size < size)
	44	fortify_panic(__func__);
	45	return __underlying_strncpy(p, q, size);
	46	}
	47
	48	__FORTIFY_INLINE char strcat(char p, const char *q)
	49	{
	50	size_t p_size = __builtin_object_size(p, 1);
	51
	52	if (p_size == (size_t)-1)
	53	return __underlying_strcat(p, q);
	54	if (strlcat(p, q, p_size) >= p_size)
	55	fortify_panic(__func__);
	56	return p;
	57	}
	58
369cd216 KC	59	extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
	60	__FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
	61	{
	62	size_t p_size = __builtin_object_size(p, 1);
	63	__kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
	64
	65	if (p_size <= ret && maxlen != ret)
	66	fortify_panic(__func__);
	67	return ret;
	68	}
	69
a28a6e86 FL	70	__FORTIFY_INLINE __kernel_size_t strlen(const char *p)
	71	{
	72	__kernel_size_t ret;
	73	size_t p_size = __builtin_object_size(p, 1);
	74
	75	/* Work around gcc excess stack consumption issue */
	76	if (p_size == (size_t)-1 \|\|
	77	(__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
	78	return __underlying_strlen(p);
	79	ret = strnlen(p, p_size);
	80	if (p_size <= ret)
	81	fortify_panic(__func__);
	82	return ret;
	83	}
	84
a28a6e86 FL	85	/* defined after fortified strlen to reuse it */
	86	extern size_t __real_strlcpy(char , const char , size_t) __RENAME(strlcpy);
	87	__FORTIFY_INLINE size_t strlcpy(char p, const char q, size_t size)
	88	{
	89	size_t ret;
	90	size_t p_size = __builtin_object_size(p, 1);
	91	size_t q_size = __builtin_object_size(q, 1);
	92
	93	if (p_size == (size_t)-1 && q_size == (size_t)-1)
	94	return __real_strlcpy(p, q, size);
	95	ret = strlen(q);
	96	if (size) {
	97	size_t len = (ret >= size) ? size - 1 : ret;
	98
	99	if (__builtin_constant_p(len) && len >= p_size)
	100	__write_overflow();
	101	if (len >= p_size)
	102	fortify_panic(__func__);
	103	__underlying_memcpy(p, q, len);
	104	p[len] = '\0';
	105	}
	106	return ret;
	107	}
	108
	109	/* defined after fortified strnlen to reuse it */
	110	extern ssize_t __real_strscpy(char , const char , size_t) __RENAME(strscpy);
	111	__FORTIFY_INLINE ssize_t strscpy(char p, const char q, size_t size)
	112	{
	113	size_t len;
	114	/* Use string size rather than possible enclosing struct size. */
	115	size_t p_size = __builtin_object_size(p, 1);
	116	size_t q_size = __builtin_object_size(q, 1);
	117
	118	/* If we cannot get size of p and q default to call strscpy. */
	119	if (p_size == (size_t) -1 && q_size == (size_t) -1)
	120	return __real_strscpy(p, q, size);
	121
	122	/*
	123	* If size can be known at compile time and is greater than
	124	* p_size, generate a compile time write overflow error.
	125	*/
	126	if (__builtin_constant_p(size) && size > p_size)
	127	__write_overflow();
	128
	129	/*
	130	* This call protects from read overflow, because len will default to q
	131	* length if it smaller than size.
	132	*/
	133	len = strnlen(q, size);
	134	/*
	135	* If len equals size, we will copy only size bytes which leads to
	136	* -E2BIG being returned.
	137	* Otherwise we will copy len + 1 because of the final '\O'.
	138	*/
	139	len = len == size ? size : len + 1;
	140
	141	/*
	142	* Generate a runtime write overflow error if len is greater than
	143	* p_size.
	144	*/
	145	if (len > p_size)
	146	fortify_panic(__func__);
	147
	148	/*
149	* We can now safely call vanilla strscpy because we are protected from:
150	* 1. Read overflow thanks to call to strnlen().
151	* 2. Write overflow thanks to above ifs.
152	*/
153	return __real_strscpy(p, q, len);
154	}
155
156	/* defined after fortified strlen and strnlen to reuse them */
157	__FORTIFY_INLINE char strncat(char p, const char *q, __kernel_size_t count)
158	{
159	size_t p_len, copy_len;
160	size_t p_size = __builtin_object_size(p, 1);
161	size_t q_size = __builtin_object_size(q, 1);
162
163	if (p_size == (size_t)-1 && q_size == (size_t)-1)
164	return __underlying_strncat(p, q, count);
165	p_len = strlen(p);
166	copy_len = strnlen(q, count);
167	if (p_size < p_len + copy_len + 1)
168	fortify_panic(__func__);
169	__underlying_memcpy(p + p_len, q, copy_len);
170	p[p_len + copy_len] = '\0';
171	return p;
172	}
173
174	__FORTIFY_INLINE void memset(void p, int c, __kernel_size_t size)
175	{
176	size_t p_size = __builtin_object_size(p, 0);
177
178	if (__builtin_constant_p(size) && p_size < size)
179	__write_overflow();
180	if (p_size < size)
181	fortify_panic(__func__);
182	return __underlying_memset(p, c, size);
183	}
184
185	__FORTIFY_INLINE void memcpy(void p, const void *q, __kernel_size_t size)
186	{
187	size_t p_size = __builtin_object_size(p, 0);
188	size_t q_size = __builtin_object_size(q, 0);
189
190	if (__builtin_constant_p(size)) {
191	if (p_size < size)
192	__write_overflow();
193	if (q_size < size)
194	__read_overflow2();
195	}
196	if (p_size < size \|\| q_size < size)
197	fortify_panic(__func__);
198	return __underlying_memcpy(p, q, size);
199	}
200
201	__FORTIFY_INLINE void memmove(void p, const void *q, __kernel_size_t size)
202	{
203	size_t p_size = __builtin_object_size(p, 0);
204	size_t q_size = __builtin_object_size(q, 0);
205
206	if (__builtin_constant_p(size)) {
207	if (p_size < size)
208	__write_overflow();
209	if (q_size < size)
210	__read_overflow2();
211	}
212	if (p_size < size \|\| q_size < size)
213	fortify_panic(__func__);
214	return __underlying_memmove(p, q, size);
215	}
216
217	extern void __real_memscan(void , int, __kernel_size_t) __RENAME(memscan);
218	__FORTIFY_INLINE void memscan(void p, int c, __kernel_size_t size)
219	{
220	size_t p_size = __builtin_object_size(p, 0);
221
222	if (__builtin_constant_p(size) && p_size < size)
223	__read_overflow();
224	if (p_size < size)
225	fortify_panic(__func__);
226	return __real_memscan(p, c, size);
227	}
228
229	__FORTIFY_INLINE int memcmp(const void p, const void q, __kernel_size_t size)
230	{
231	size_t p_size = __builtin_object_size(p, 0);
232	size_t q_size = __builtin_object_size(q, 0);
233
234	if (__builtin_constant_p(size)) {
235	if (p_size < size)
236	__read_overflow();
237	if (q_size < size)
238	__read_overflow2();
239	}
240	if (p_size < size \|\| q_size < size)
241	fortify_panic(__func__);
242	return __underlying_memcmp(p, q, size);
243	}
244
245	__FORTIFY_INLINE void memchr(const void p, int c, __kernel_size_t size)
246	{
247	size_t p_size = __builtin_object_size(p, 0);
248
249	if (__builtin_constant_p(size) && p_size < size)
250	__read_overflow();
251	if (p_size < size)
252	fortify_panic(__func__);
253	return __underlying_memchr(p, c, size);
254	}
255
256	void __real_memchr_inv(const void s, int c, size_t n) __RENAME(memchr_inv);
257	__FORTIFY_INLINE void memchr_inv(const void p, int c, size_t size)
258	{
259	size_t p_size = __builtin_object_size(p, 0);
260
261	if (__builtin_constant_p(size) && p_size < size)
262	__read_overflow();
263	if (p_size < size)
264	fortify_panic(__func__);
265	return __real_memchr_inv(p, c, size);
266	}
267
268	extern void __real_kmemdup(const void src, size_t len, gfp_t gfp) __RENAME(kmemdup);
269	__FORTIFY_INLINE void kmemdup(const void p, size_t size, gfp_t gfp)
270	{
271	size_t p_size = __builtin_object_size(p, 0);
272
273	if (__builtin_constant_p(size) && p_size < size)
274	__read_overflow();
275	if (p_size < size)
276	fortify_panic(__func__);
277	return __real_kmemdup(p, size, gfp);
278	}
279
280	/* defined after fortified strlen and memcpy to reuse them */
281	__FORTIFY_INLINE char strcpy(char p, const char *q)
282	{
283	size_t p_size = __builtin_object_size(p, 1);
284	size_t q_size = __builtin_object_size(q, 1);
285	size_t size;
286
287	if (p_size == (size_t)-1 && q_size == (size_t)-1)
288	return __underlying_strcpy(p, q);
289	size = strlen(q) + 1;
072af0c6 KC	290	/* Compile-time check for const size overflow. */
	291	if (__builtin_constant_p(size) && p_size < size)
	292	__write_overflow();
	293	/* Run-time check for dynamic size overflow. */
a28a6e86 FL	294	if (p_size < size)
	295	fortify_panic(__func__);
	296	memcpy(p, q, size);
	297	return p;
	298	}
	299
	300	/* Don't use these outside the FORITFY_SOURCE implementation */
	301	#undef __underlying_memchr
	302	#undef __underlying_memcmp
	303	#undef __underlying_memcpy
	304	#undef __underlying_memmove
	305	#undef __underlying_memset
	306	#undef __underlying_strcat
	307	#undef __underlying_strcpy
	308	#undef __underlying_strlen
	309	#undef __underlying_strncat
	310	#undef __underlying_strncpy
	311
	312	#endif /* _LINUX_FORTIFY_STRING_H_ */