1 #ifndef __SCORE_UACCESS_H
2 #define __SCORE_UACCESS_H
3
4 #include <linux/kernel.h>
5 #include <linux/errno.h>
6 #include <linux/thread_info.h>
7
8 #define VERIFY_READ 0
9 #define VERIFY_WRITE 1
10
11 #define get_ds() (KERNEL_DS)
12 #define get_fs() (current_thread_info()->addr_limit)
13 #define segment_eq(a, b) ((a).seg == (b).seg)
14
15 /*
16 * Is a address valid? This does a straighforward calculation rather
17 * than tests.
18 *
19 * Address valid if:
20 * - "addr" doesn't have any high-bits set
21 * - AND "size" doesn't have any high-bits set
22 * - AND "addr+size" doesn't have any high-bits set
23 * - OR we are in kernel mode.
24 *
25 * __ua_size() is a trick to avoid runtime checking of positive constant
26 * sizes; for those we already know at compile time that the size is ok.
27 */
28 #define __ua_size(size) \
29 ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
30
31 /*
32 * access_ok: - Checks if a user space pointer is valid
33 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
34 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
35 * to write to a block, it is always safe to read from it.
36 * @addr: User space pointer to start of block to check
37 * @size: Size of block to check
38 *
39 * Context: User context only. This function may sleep if pagefaults are
40 * enabled.
41 *
42 * Checks if a pointer to a block of memory in user space is valid.
43 *
44 * Returns true (nonzero) if the memory block may be valid, false (zero)
45 * if it is definitely invalid.
46 *
47 * Note that, depending on architecture, this function probably just
48 * checks that the pointer is in the user space range - after calling
49 * this function, memory access functions may still return -EFAULT.
50 */
51
52 #define __access_ok(addr, size) \
53 (((long)((get_fs().seg) & \
54 ((addr) | ((addr) + (size)) | \
55 __ua_size(size)))) == 0)
56
57 #define access_ok(type, addr, size) \
58 likely(__access_ok((unsigned long)(addr), (size)))
59
60 /*
61 * put_user: - Write a simple value into user space.
62 * @x: Value to copy to user space.
63 * @ptr: Destination address, in user space.
64 *
65 * Context: User context only. This function may sleep if pagefaults are
66 * enabled.
67 *
68 * This macro copies a single simple value from kernel space to user
69 * space. It supports simple types like char and int, but not larger
70 * data types like structures or arrays.
71 *
72 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
73 * to the result of dereferencing @ptr.
74 *
75 * Returns zero on success, or -EFAULT on error.
76 */
77 #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
78
79 /*
80 * get_user: - Get a simple variable from user space.
81 * @x: Variable to store result.
82 * @ptr: Source address, in user space.
83 *
84 * Context: User context only. This function may sleep if pagefaults are
85 * enabled.
86 *
87 * This macro copies a single simple variable from user space to kernel
88 * space. It supports simple types like char and int, but not larger
89 * data types like structures or arrays.
90 *
91 * @ptr must have pointer-to-simple-variable type, and the result of
92 * dereferencing @ptr must be assignable to @x without a cast.
93 *
94 * Returns zero on success, or -EFAULT on error.
95 * On error, the variable @x is set to zero.
96 */
97 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
98
99 /*
100 * __put_user: - Write a simple value into user space, with less checking.
101 * @x: Value to copy to user space.
102 * @ptr: Destination address, in user space.
103 *
104 * Context: User context only. This function may sleep if pagefaults are
105 * enabled.
106 *
107 * This macro copies a single simple value from kernel space to user
108 * space. It supports simple types like char and int, but not larger
109 * data types like structures or arrays.
110 *
111 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
112 * to the result of dereferencing @ptr.
113 *
114 * Caller must check the pointer with access_ok() before calling this
115 * function.
116 *
117 * Returns zero on success, or -EFAULT on error.
118 */
119 #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
120
121 /*
122 * __get_user: - Get a simple variable from user space, with less checking.
123 * @x: Variable to store result.
124 * @ptr: Source address, in user space.
125 *
126 * Context: User context only. This function may sleep if pagefaults are
127 * enabled.
128 *
129 * This macro copies a single simple variable from user space to kernel
130 * space. It supports simple types like char and int, but not larger
131 * data types like structures or arrays.
132 *
133 * @ptr must have pointer-to-simple-variable type, and the result of
134 * dereferencing @ptr must be assignable to @x without a cast.
135 *
136 * Caller must check the pointer with access_ok() before calling this
137 * function.
138 *
139 * Returns zero on success, or -EFAULT on error.
140 * On error, the variable @x is set to zero.
141 */
142 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
143
144 struct __large_struct { unsigned long buf[100]; };
145 #define __m(x) (*(struct __large_struct __user *)(x))
146
147 /*
148 * Yuck. We need two variants, one for 64bit operation and one
149 * for 32 bit mode and old iron.
150 */
151 extern void __get_user_unknown(void);
152
153 #define __get_user_common(val, size, ptr) \
154 do { \
155 switch (size) { \
156 case 1: \
157 __get_user_asm(val, "lb", ptr); \
158 break; \
159 case 2: \
160 __get_user_asm(val, "lh", ptr); \
161 break; \
162 case 4: \
163 __get_user_asm(val, "lw", ptr); \
164 break; \
165 case 8: \
166 if ((copy_from_user((void *)&val, ptr, 8)) == 0) \
167 __gu_err = 0; \
168 else \
169 __gu_err = -EFAULT; \
170 break; \
171 default: \
172 __get_user_unknown(); \
173 break; \
174 } \
175 } while (0)
176
177 #define __get_user_nocheck(x, ptr, size) \
178 ({ \
179 long __gu_err = 0; \
180 __get_user_common((x), size, ptr); \
181 __gu_err; \
182 })
183
184 #define __get_user_check(x, ptr, size) \
185 ({ \
186 long __gu_err = -EFAULT; \
187 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
188 \
189 if (likely(access_ok(VERIFY_READ, __gu_ptr, size))) \
190 __get_user_common((x), size, __gu_ptr); \
191 \
192 __gu_err; \
193 })
194
195 #define __get_user_asm(val, insn, addr) \
196 { \
197 long __gu_tmp; \
198 \
199 __asm__ __volatile__( \
200 "1:" insn " %1, %3\n" \
201 "2:\n" \
202 ".section .fixup,\"ax\"\n" \
203 "3:li %0, %4\n" \
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
copy_from_user(void * to,const void * from,unsigned long len)299 copy_from_user(void *to, const void *from, unsigned long len)
300 {
301 unsigned long over;
302
303 if (access_ok(VERIFY_READ, from, len))
304 return __copy_tofrom_user(to, from, len);
305
306 if ((unsigned long)from < TASK_SIZE) {
307 over = (unsigned long)from + len - TASK_SIZE;
308 return __copy_tofrom_user(to, from, len - over) + over;
309 }
310 return len;
311 }
312
313 static inline unsigned long
copy_to_user(void * to,const void * from,unsigned long len)314 copy_to_user(void *to, const void *from, unsigned long len)
315 {
316 unsigned long over;
317
318 if (access_ok(VERIFY_WRITE, to, len))
319 return __copy_tofrom_user(to, from, len);
320
321 if ((unsigned long)to < TASK_SIZE) {
322 over = (unsigned long)to + len - TASK_SIZE;
323 return __copy_tofrom_user(to, from, len - over) + over;
324 }
325 return len;
326 }
327
328 #define __copy_from_user(to, from, len) \
329 __copy_tofrom_user((to), (from), (len))
330
331 #define __copy_to_user(to, from, len) \
332 __copy_tofrom_user((to), (from), (len))
333
334 static inline unsigned long
__copy_to_user_inatomic(void * to,const void * from,unsigned long len)335 __copy_to_user_inatomic(void *to, const void *from, unsigned long len)
336 {
337 return __copy_to_user(to, from, len);
338 }
339
340 static inline unsigned long
__copy_from_user_inatomic(void * to,const void * from,unsigned long len)341 __copy_from_user_inatomic(void *to, const void *from, unsigned long len)
342 {
343 return __copy_from_user(to, from, len);
344 }
345
346 #define __copy_in_user(to, from, len) __copy_from_user(to, from, len)
347
348 static inline unsigned long
copy_in_user(void * to,const void * from,unsigned long len)349 copy_in_user(void *to, const void *from, unsigned long len)
350 {
351 if (access_ok(VERIFY_READ, from, len) &&
352 access_ok(VERFITY_WRITE, to, len))
353 return copy_from_user(to, from, len);
354 }
355
356 /*
357 * __clear_user: - Zero a block of memory in user space, with less checking.
358 * @to: Destination address, in user space.
359 * @n: Number of bytes to zero.
360 *
361 * Zero a block of memory in user space. Caller must check
362 * the specified block with access_ok() before calling this function.
363 *
364 * Returns number of bytes that could not be cleared.
365 * On success, this will be zero.
366 */
367 extern unsigned long __clear_user(void __user *src, unsigned long size);
368
clear_user(char * src,unsigned long size)369 static inline unsigned long clear_user(char *src, unsigned long size)
370 {
371 if (access_ok(VERIFY_WRITE, src, size))
372 return __clear_user(src, size);
373
374 return -EFAULT;
375 }
376 /*
377 * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
378 * @dst: Destination address, in kernel space. This buffer must be at
379 * least @count bytes long.
380 * @src: Source address, in user space.
381 * @count: Maximum number of bytes to copy, including the trailing NUL.
382 *
383 * Copies a NUL-terminated string from userspace to kernel space.
384 * Caller must check the specified block with access_ok() before calling
385 * this function.
386 *
387 * On success, returns the length of the string (not including the trailing
388 * NUL).
389 *
390 * If access to userspace fails, returns -EFAULT (some data may have been
391 * copied).
392 *
393 * If @count is smaller than the length of the string, copies @count bytes
394 * and returns @count.
395 */
396 extern int __strncpy_from_user(char *dst, const char *src, long len);
397
strncpy_from_user(char * dst,const char * src,long len)398 static inline int strncpy_from_user(char *dst, const char *src, long len)
399 {
400 if (access_ok(VERIFY_READ, src, 1))
401 return __strncpy_from_user(dst, src, len);
402
403 return -EFAULT;
404 }
405
406 extern int __strlen_user(const char *src);
strlen_user(const char __user * src)407 static inline long strlen_user(const char __user *src)
408 {
409 return __strlen_user(src);
410 }
411
412 extern int __strnlen_user(const char *str, long len);
strnlen_user(const char __user * str,long len)413 static inline long strnlen_user(const char __user *str, long len)
414 {
415 if (!access_ok(VERIFY_READ, str, 0))
416 return 0;
417 else
418 return __strnlen_user(str, len);
419 }
420
421 struct exception_table_entry {
422 unsigned long insn;
423 unsigned long fixup;
424 };
425
426 extern int fixup_exception(struct pt_regs *regs);
427
428 #endif /* __SCORE_UACCESS_H */
429
430