[mirror_ubuntu-jammy-kernel.git] / include / linux / fortify-string.h

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


#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;
}

__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;
}

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;
}

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