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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
ffa818b4 CL |
2 | #ifndef __SCORE_UACCESS_H |
3 | #define __SCORE_UACCESS_H | |
4 | ||
5 | #include <linux/kernel.h> | |
88dd4a74 | 6 | #include <asm/extable.h> |
ffa818b4 | 7 | |
ffa818b4 CL |
8 | #define get_ds() (KERNEL_DS) |
9 | #define get_fs() (current_thread_info()->addr_limit) | |
10 | #define segment_eq(a, b) ((a).seg == (b).seg) | |
11 | ||
6bc9a396 | 12 | /* |
ffa818b4 CL |
13 | * Is a address valid? This does a straighforward calculation rather |
14 | * than tests. | |
15 | * | |
16 | * Address valid if: | |
17 | * - "addr" doesn't have any high-bits set | |
18 | * - AND "size" doesn't have any high-bits set | |
19 | * - AND "addr+size" doesn't have any high-bits set | |
20 | * - OR we are in kernel mode. | |
6bc9a396 | 21 | * |
ffa818b4 CL |
22 | * __ua_size() is a trick to avoid runtime checking of positive constant |
23 | * sizes; for those we already know at compile time that the size is ok. | |
6bc9a396 | 24 | */ |
ffa818b4 CL |
25 | #define __ua_size(size) \ |
26 | ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size)) | |
27 | ||
28 | /* | |
29 | * access_ok: - Checks if a user space pointer is valid | |
30 | * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that | |
31 | * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe | |
32 | * to write to a block, it is always safe to read from it. | |
33 | * @addr: User space pointer to start of block to check | |
34 | * @size: Size of block to check | |
35 | * | |
b3c395ef DH |
36 | * Context: User context only. This function may sleep if pagefaults are |
37 | * enabled. | |
ffa818b4 CL |
38 | * |
39 | * Checks if a pointer to a block of memory in user space is valid. | |
40 | * | |
41 | * Returns true (nonzero) if the memory block may be valid, false (zero) | |
42 | * if it is definitely invalid. | |
43 | * | |
44 | * Note that, depending on architecture, this function probably just | |
45 | * checks that the pointer is in the user space range - after calling | |
46 | * this function, memory access functions may still return -EFAULT. | |
47 | */ | |
48 | ||
49 | #define __access_ok(addr, size) \ | |
50 | (((long)((get_fs().seg) & \ | |
51 | ((addr) | ((addr) + (size)) | \ | |
52 | __ua_size(size)))) == 0) | |
53 | ||
54 | #define access_ok(type, addr, size) \ | |
55 | likely(__access_ok((unsigned long)(addr), (size))) | |
56 | ||
57 | /* | |
58 | * put_user: - Write a simple value into user space. | |
59 | * @x: Value to copy to user space. | |
60 | * @ptr: Destination address, in user space. | |
61 | * | |
b3c395ef DH |
62 | * Context: User context only. This function may sleep if pagefaults are |
63 | * enabled. | |
ffa818b4 CL |
64 | * |
65 | * This macro copies a single simple value from kernel space to user | |
66 | * space. It supports simple types like char and int, but not larger | |
67 | * data types like structures or arrays. | |
68 | * | |
69 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable | |
70 | * to the result of dereferencing @ptr. | |
71 | * | |
72 | * Returns zero on success, or -EFAULT on error. | |
73 | */ | |
74 | #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr))) | |
75 | ||
76 | /* | |
77 | * get_user: - Get a simple variable from user space. | |
78 | * @x: Variable to store result. | |
79 | * @ptr: Source address, in user space. | |
80 | * | |
b3c395ef DH |
81 | * Context: User context only. This function may sleep if pagefaults are |
82 | * enabled. | |
ffa818b4 CL |
83 | * |
84 | * This macro copies a single simple variable from user space to kernel | |
85 | * space. It supports simple types like char and int, but not larger | |
86 | * data types like structures or arrays. | |
87 | * | |
88 | * @ptr must have pointer-to-simple-variable type, and the result of | |
89 | * dereferencing @ptr must be assignable to @x without a cast. | |
90 | * | |
91 | * Returns zero on success, or -EFAULT on error. | |
92 | * On error, the variable @x is set to zero. | |
93 | */ | |
94 | #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr))) | |
95 | ||
96 | /* | |
97 | * __put_user: - Write a simple value into user space, with less checking. | |
98 | * @x: Value to copy to user space. | |
99 | * @ptr: Destination address, in user space. | |
100 | * | |
b3c395ef DH |
101 | * Context: User context only. This function may sleep if pagefaults are |
102 | * enabled. | |
ffa818b4 CL |
103 | * |
104 | * This macro copies a single simple value from kernel space to user | |
105 | * space. It supports simple types like char and int, but not larger | |
106 | * data types like structures or arrays. | |
107 | * | |
108 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable | |
109 | * to the result of dereferencing @ptr. | |
110 | * | |
111 | * Caller must check the pointer with access_ok() before calling this | |
112 | * function. | |
113 | * | |
114 | * Returns zero on success, or -EFAULT on error. | |
115 | */ | |
116 | #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr))) | |
117 | ||
118 | /* | |
119 | * __get_user: - Get a simple variable from user space, with less checking. | |
120 | * @x: Variable to store result. | |
121 | * @ptr: Source address, in user space. | |
122 | * | |
b3c395ef DH |
123 | * Context: User context only. This function may sleep if pagefaults are |
124 | * enabled. | |
ffa818b4 CL |
125 | * |
126 | * This macro copies a single simple variable from user space to kernel | |
127 | * space. It supports simple types like char and int, but not larger | |
128 | * data types like structures or arrays. | |
129 | * | |
130 | * @ptr must have pointer-to-simple-variable type, and the result of | |
131 | * dereferencing @ptr must be assignable to @x without a cast. | |
132 | * | |
133 | * Caller must check the pointer with access_ok() before calling this | |
134 | * function. | |
135 | * | |
136 | * Returns zero on success, or -EFAULT on error. | |
137 | * On error, the variable @x is set to zero. | |
138 | */ | |
139 | #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr))) | |
140 | ||
141 | struct __large_struct { unsigned long buf[100]; }; | |
142 | #define __m(x) (*(struct __large_struct __user *)(x)) | |
143 | ||
144 | /* | |
145 | * Yuck. We need two variants, one for 64bit operation and one | |
146 | * for 32 bit mode and old iron. | |
147 | */ | |
148 | extern void __get_user_unknown(void); | |
149 | ||
150 | #define __get_user_common(val, size, ptr) \ | |
151 | do { \ | |
152 | switch (size) { \ | |
153 | case 1: \ | |
154 | __get_user_asm(val, "lb", ptr); \ | |
155 | break; \ | |
156 | case 2: \ | |
157 | __get_user_asm(val, "lh", ptr); \ | |
158 | break; \ | |
159 | case 4: \ | |
160 | __get_user_asm(val, "lw", ptr); \ | |
161 | break; \ | |
162 | case 8: \ | |
c2f18fa4 | 163 | if (__copy_from_user((void *)&val, ptr, 8) == 0) \ |
ffa818b4 CL |
164 | __gu_err = 0; \ |
165 | else \ | |
166 | __gu_err = -EFAULT; \ | |
167 | break; \ | |
168 | default: \ | |
169 | __get_user_unknown(); \ | |
170 | break; \ | |
171 | } \ | |
172 | } while (0) | |
173 | ||
174 | #define __get_user_nocheck(x, ptr, size) \ | |
175 | ({ \ | |
176 | long __gu_err = 0; \ | |
177 | __get_user_common((x), size, ptr); \ | |
178 | __gu_err; \ | |
179 | }) | |
180 | ||
181 | #define __get_user_check(x, ptr, size) \ | |
182 | ({ \ | |
183 | long __gu_err = -EFAULT; \ | |
184 | const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ | |
185 | \ | |
186 | if (likely(access_ok(VERIFY_READ, __gu_ptr, size))) \ | |
187 | __get_user_common((x), size, __gu_ptr); \ | |
c2f18fa4 AV |
188 | else \ |
189 | (x) = 0; \ | |
ffa818b4 CL |
190 | \ |
191 | __gu_err; \ | |
192 | }) | |
193 | ||
194 | #define __get_user_asm(val, insn, addr) \ | |
195 | { \ | |
196 | long __gu_tmp; \ | |
197 | \ | |
198 | __asm__ __volatile__( \ | |
199 | "1:" insn " %1, %3\n" \ | |
200 | "2:\n" \ | |
201 | ".section .fixup,\"ax\"\n" \ | |
202 | "3:li %0, %4\n" \ | |
c2f18fa4 | 203 | "li %1, 0\n" \ |
ffa818b4 CL |
204 | "j 2b\n" \ |
205 | ".previous\n" \ | |
206 | ".section __ex_table,\"a\"\n" \ | |
207 | ".word 1b, 3b\n" \ | |
208 | ".previous\n" \ | |
209 | : "=r" (__gu_err), "=r" (__gu_tmp) \ | |
210 | : "0" (0), "o" (__m(addr)), "i" (-EFAULT)); \ | |
211 | \ | |
212 | (val) = (__typeof__(*(addr))) __gu_tmp; \ | |
213 | } | |
214 | ||
215 | /* | |
216 | * Yuck. We need two variants, one for 64bit operation and one | |
217 | * for 32 bit mode and old iron. | |
218 | */ | |
219 | #define __put_user_nocheck(val, ptr, size) \ | |
220 | ({ \ | |
221 | __typeof__(*(ptr)) __pu_val; \ | |
222 | long __pu_err = 0; \ | |
223 | \ | |
224 | __pu_val = (val); \ | |
225 | switch (size) { \ | |
226 | case 1: \ | |
227 | __put_user_asm("sb", ptr); \ | |
228 | break; \ | |
229 | case 2: \ | |
230 | __put_user_asm("sh", ptr); \ | |
231 | break; \ | |
232 | case 4: \ | |
233 | __put_user_asm("sw", ptr); \ | |
234 | break; \ | |
235 | case 8: \ | |
236 | if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0) \ | |
237 | __pu_err = 0; \ | |
238 | else \ | |
239 | __pu_err = -EFAULT; \ | |
240 | break; \ | |
241 | default: \ | |
242 | __put_user_unknown(); \ | |
243 | break; \ | |
244 | } \ | |
245 | __pu_err; \ | |
246 | }) | |
247 | ||
248 | ||
249 | #define __put_user_check(val, ptr, size) \ | |
250 | ({ \ | |
251 | __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ | |
252 | __typeof__(*(ptr)) __pu_val = (val); \ | |
253 | long __pu_err = -EFAULT; \ | |
254 | \ | |
255 | if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) { \ | |
256 | switch (size) { \ | |
257 | case 1: \ | |
258 | __put_user_asm("sb", __pu_addr); \ | |
259 | break; \ | |
260 | case 2: \ | |
261 | __put_user_asm("sh", __pu_addr); \ | |
262 | break; \ | |
263 | case 4: \ | |
264 | __put_user_asm("sw", __pu_addr); \ | |
265 | break; \ | |
266 | case 8: \ | |
267 | if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\ | |
268 | __pu_err = 0; \ | |
269 | else \ | |
270 | __pu_err = -EFAULT; \ | |
271 | break; \ | |
272 | default: \ | |
273 | __put_user_unknown(); \ | |
274 | break; \ | |
275 | } \ | |
276 | } \ | |
277 | __pu_err; \ | |
278 | }) | |
279 | ||
280 | #define __put_user_asm(insn, ptr) \ | |
281 | __asm__ __volatile__( \ | |
282 | "1:" insn " %2, %3\n" \ | |
283 | "2:\n" \ | |
284 | ".section .fixup,\"ax\"\n" \ | |
285 | "3:li %0, %4\n" \ | |
286 | "j 2b\n" \ | |
287 | ".previous\n" \ | |
288 | ".section __ex_table,\"a\"\n" \ | |
289 | ".word 1b, 3b\n" \ | |
290 | ".previous\n" \ | |
291 | : "=r" (__pu_err) \ | |
292 | : "0" (0), "r" (__pu_val), "o" (__m(ptr)), \ | |
293 | "i" (-EFAULT)); | |
294 | ||
295 | extern void __put_user_unknown(void); | |
296 | extern int __copy_tofrom_user(void *to, const void *from, unsigned long len); | |
297 | ||
298 | static inline unsigned long | |
dc142535 | 299 | raw_copy_from_user(void *to, const void __user *from, unsigned long len) |
ffa818b4 | 300 | { |
dc142535 | 301 | return __copy_tofrom_user(to, (__force const void *)from, len); |
ffa818b4 CL |
302 | } |
303 | ||
304 | static inline unsigned long | |
dc142535 | 305 | raw_copy_to_user(void __user *to, const void *from, unsigned long len) |
ffa818b4 | 306 | { |
dc142535 | 307 | return __copy_tofrom_user((__force void *)to, from, len); |
ffa818b4 | 308 | } |
6bc9a396 | 309 | |
dc142535 AV |
310 | #define INLINE_COPY_FROM_USER |
311 | #define INLINE_COPY_TO_USER | |
ffa818b4 CL |
312 | |
313 | /* | |
314 | * __clear_user: - Zero a block of memory in user space, with less checking. | |
315 | * @to: Destination address, in user space. | |
316 | * @n: Number of bytes to zero. | |
317 | * | |
318 | * Zero a block of memory in user space. Caller must check | |
319 | * the specified block with access_ok() before calling this function. | |
320 | * | |
321 | * Returns number of bytes that could not be cleared. | |
322 | * On success, this will be zero. | |
323 | */ | |
324 | extern unsigned long __clear_user(void __user *src, unsigned long size); | |
325 | ||
326 | static inline unsigned long clear_user(char *src, unsigned long size) | |
327 | { | |
328 | if (access_ok(VERIFY_WRITE, src, size)) | |
329 | return __clear_user(src, size); | |
330 | ||
331 | return -EFAULT; | |
332 | } | |
333 | /* | |
334 | * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking. | |
335 | * @dst: Destination address, in kernel space. This buffer must be at | |
336 | * least @count bytes long. | |
337 | * @src: Source address, in user space. | |
338 | * @count: Maximum number of bytes to copy, including the trailing NUL. | |
339 | * | |
340 | * Copies a NUL-terminated string from userspace to kernel space. | |
341 | * Caller must check the specified block with access_ok() before calling | |
342 | * this function. | |
343 | * | |
344 | * On success, returns the length of the string (not including the trailing | |
345 | * NUL). | |
346 | * | |
347 | * If access to userspace fails, returns -EFAULT (some data may have been | |
348 | * copied). | |
349 | * | |
350 | * If @count is smaller than the length of the string, copies @count bytes | |
351 | * and returns @count. | |
352 | */ | |
353 | extern int __strncpy_from_user(char *dst, const char *src, long len); | |
354 | ||
355 | static inline int strncpy_from_user(char *dst, const char *src, long len) | |
356 | { | |
357 | if (access_ok(VERIFY_READ, src, 1)) | |
358 | return __strncpy_from_user(dst, src, len); | |
359 | ||
360 | return -EFAULT; | |
361 | } | |
362 | ||
ffa818b4 CL |
363 | extern int __strnlen_user(const char *str, long len); |
364 | static inline long strnlen_user(const char __user *str, long len) | |
365 | { | |
366 | if (!access_ok(VERIFY_READ, str, 0)) | |
367 | return 0; | |
368 | else | |
369 | return __strnlen_user(str, len); | |
370 | } | |
371 | ||
ffa818b4 | 372 | #endif /* __SCORE_UACCESS_H */ |
6bc9a396 | 373 |