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.
40 *
41 * Checks if a pointer to a block of memory in user space is valid.
42 *
43 * Returns true (nonzero) if the memory block may be valid, false (zero)
44 * if it is definitely invalid.
45 *
46 * Note that, depending on architecture, this function probably just
47 * checks that the pointer is in the user space range - after calling
48 * this function, memory access functions may still return -EFAULT.
49 */
50
51 #define __access_ok(addr, size) \
52 (((long)((get_fs().seg) & \
53 ((addr) | ((addr) + (size)) | \
54 __ua_size(size)))) == 0)
55
56 #define access_ok(type, addr, size) \
57 likely(__access_ok((unsigned long)(addr), (size)))
58
59 /*
60 * put_user: - Write a simple value into user space.
61 * @x: Value to copy to user space.
62 * @ptr: Destination address, in user space.
63 *
64 * Context: User context only. This function may sleep.
65 *
66 * This macro copies a single simple value from kernel space to user
67 * space. It supports simple types like char and int, but not larger
68 * data types like structures or arrays.
69 *
70 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
71 * to the result of dereferencing @ptr.
72 *
73 * Returns zero on success, or -EFAULT on error.
74 */
75 #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
76
77 /*
78 * get_user: - Get a simple variable from user space.
79 * @x: Variable to store result.
80 * @ptr: Source address, in user space.
81 *
82 * Context: User context only. This function may sleep.
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 *
101 * Context: User context only. This function may sleep.
102 *
103 * This macro copies a single simple value from kernel space to user
104 * space. It supports simple types like char and int, but not larger
105 * data types like structures or arrays.
106 *
107 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
108 * to the result of dereferencing @ptr.
109 *
110 * Caller must check the pointer with access_ok() before calling this
111 * function.
112 *
113 * Returns zero on success, or -EFAULT on error.
114 */
115 #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
116
117 /*
118 * __get_user: - Get a simple variable from user space, with less checking.
119 * @x: Variable to store result.
120 * @ptr: Source address, in user space.
121 *
122 * Context: User context only. This function may sleep.
123 *
124 * This macro copies a single simple variable from user space to kernel
125 * space. It supports simple types like char and int, but not larger
126 * data types like structures or arrays.
127 *
128 * @ptr must have pointer-to-simple-variable type, and the result of
129 * dereferencing @ptr must be assignable to @x without a cast.
130 *
131 * Caller must check the pointer with access_ok() before calling this
132 * function.
133 *
134 * Returns zero on success, or -EFAULT on error.
135 * On error, the variable @x is set to zero.
136 */
137 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
138
139 struct __large_struct { unsigned long buf[100]; };
140 #define __m(x) (*(struct __large_struct __user *)(x))
141
142 /*
143 * Yuck. We need two variants, one for 64bit operation and one
144 * for 32 bit mode and old iron.
145 */
146 extern void __get_user_unknown(void);
147
148 #define __get_user_common(val, size, ptr) \
149 do { \
150 switch (size) { \
151 case 1: \
152 __get_user_asm(val, "lb", ptr); \
153 break; \
154 case 2: \
155 __get_user_asm(val, "lh", ptr); \
156 break; \
157 case 4: \
158 __get_user_asm(val, "lw", ptr); \
159 break; \
160 case 8: \
161 if (__copy_from_user((void *)&val, ptr, 8) == 0) \
162 __gu_err = 0; \
163 else \
164 __gu_err = -EFAULT; \
165 break; \
166 default: \
167 __get_user_unknown(); \
168 break; \
169 } \
170 } while (0)
171
172 #define __get_user_nocheck(x, ptr, size) \
173 ({ \
174 long __gu_err = 0; \
175 __get_user_common((x), size, ptr); \
176 __gu_err; \
177 })
178
179 #define __get_user_check(x, ptr, size) \
180 ({ \
181 long __gu_err = -EFAULT; \
182 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
183 \
184 if (likely(access_ok(VERIFY_READ, __gu_ptr, size))) \
185 __get_user_common((x), size, __gu_ptr); \
186 else \
187 (x) = 0; \
188 \
189 __gu_err; \
190 })
191
192 #define __get_user_asm(val, insn, addr) \
193 { \
194 long __gu_tmp; \
195 \
196 __asm__ __volatile__( \
197 "1:" insn " %1, %3\n" \
198 "2:\n" \
199 ".section .fixup,\"ax\"\n" \
200 "3:li %0, %4\n" \
201 "li %1, 0\n" \
202 "j 2b\n" \
203 ".previous\n" \
204 ".section __ex_table,\"a\"\n" \
205 ".word 1b, 3b\n" \
206 ".previous\n" \
207 : "=r" (__gu_err), "=r" (__gu_tmp) \
208 : "0" (0), "o" (__m(addr)), "i" (-EFAULT)); \
209 \
210 (val) = (__typeof__(*(addr))) __gu_tmp; \
211 }
212
213 /*
214 * Yuck. We need two variants, one for 64bit operation and one
215 * for 32 bit mode and old iron.
216 */
217 #define __put_user_nocheck(val, ptr, size) \
218 ({ \
219 __typeof__(*(ptr)) __pu_val; \
220 long __pu_err = 0; \
221 \
222 __pu_val = (val); \
223 switch (size) { \
224 case 1: \
225 __put_user_asm("sb", ptr); \
226 break; \
227 case 2: \
228 __put_user_asm("sh", ptr); \
229 break; \
230 case 4: \
231 __put_user_asm("sw", ptr); \
232 break; \
233 case 8: \
234 if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0) \
235 __pu_err = 0; \
236 else \
237 __pu_err = -EFAULT; \
238 break; \
239 default: \
240 __put_user_unknown(); \
241 break; \
242 } \
243 __pu_err; \
244 })
245
246
247 #define __put_user_check(val, ptr, size) \
248 ({ \
249 __typeof__(*(ptr)) __user *__pu_addr = (ptr); \
250 __typeof__(*(ptr)) __pu_val = (val); \
251 long __pu_err = -EFAULT; \
252 \
253 if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) { \
254 switch (size) { \
255 case 1: \
256 __put_user_asm("sb", __pu_addr); \
257 break; \
258 case 2: \
259 __put_user_asm("sh", __pu_addr); \
260 break; \
261 case 4: \
262 __put_user_asm("sw", __pu_addr); \
263 break; \
264 case 8: \
265 if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\
266 __pu_err = 0; \
267 else \
268 __pu_err = -EFAULT; \
269 break; \
270 default: \
271 __put_user_unknown(); \
272 break; \
273 } \
274 } \
275 __pu_err; \
276 })
277
278 #define __put_user_asm(insn, ptr) \
279 __asm__ __volatile__( \
280 "1:" insn " %2, %3\n" \
281 "2:\n" \
282 ".section .fixup,\"ax\"\n" \
283 "3:li %0, %4\n" \
284 "j 2b\n" \
285 ".previous\n" \
286 ".section __ex_table,\"a\"\n" \
287 ".word 1b, 3b\n" \
288 ".previous\n" \
289 : "=r" (__pu_err) \
290 : "0" (0), "r" (__pu_val), "o" (__m(ptr)), \
291 "i" (-EFAULT));
292
293 extern void __put_user_unknown(void);
294 extern int __copy_tofrom_user(void *to, const void *from, unsigned long len);
295
296 static inline unsigned long
copy_from_user(void * to,const void * from,unsigned long len)297 copy_from_user(void *to, const void *from, unsigned long len)
298 {
299 unsigned long res = len;
300
301 if (likely(access_ok(VERIFY_READ, from, len)))
302 res = __copy_tofrom_user(to, from, len);
303
304 if (unlikely(res))
305 memset(to + (len - res), 0, res);
306
307 return res;
308 }
309
310 static inline unsigned long
copy_to_user(void * to,const void * from,unsigned long len)311 copy_to_user(void *to, const void *from, unsigned long len)
312 {
313 if (likely(access_ok(VERIFY_WRITE, to, len)))
314 len = __copy_tofrom_user(to, from, len);
315
316 return len;
317 }
318
319 static inline unsigned long
__copy_from_user(void * to,const void * from,unsigned long len)320 __copy_from_user(void *to, const void *from, unsigned long len)
321 {
322 unsigned long left = __copy_tofrom_user(to, from, len);
323 if (unlikely(left))
324 memset(to + (len - left), 0, left);
325 return left;
326 }
327
328 #define __copy_to_user(to, from, len) \
329 __copy_tofrom_user((to), (from), (len))
330
331 static inline unsigned long
__copy_to_user_inatomic(void * to,const void * from,unsigned long len)332 __copy_to_user_inatomic(void *to, const void *from, unsigned long len)
333 {
334 return __copy_to_user(to, from, len);
335 }
336
337 static inline unsigned long
__copy_from_user_inatomic(void * to,const void * from,unsigned long len)338 __copy_from_user_inatomic(void *to, const void *from, unsigned long len)
339 {
340 return __copy_tofrom_user(to, from, len);
341 }
342
343 #define __copy_in_user(to, from, len) __copy_tofrom_user(to, from, len)
344
345 static inline unsigned long
copy_in_user(void * to,const void * from,unsigned long len)346 copy_in_user(void *to, const void *from, unsigned long len)
347 {
348 if (access_ok(VERIFY_READ, from, len) &&
349 access_ok(VERFITY_WRITE, to, len))
350 return __copy_tofrom_user(to, from, len);
351 }
352
353 /*
354 * __clear_user: - Zero a block of memory in user space, with less checking.
355 * @to: Destination address, in user space.
356 * @n: Number of bytes to zero.
357 *
358 * Zero a block of memory in user space. Caller must check
359 * the specified block with access_ok() before calling this function.
360 *
361 * Returns number of bytes that could not be cleared.
362 * On success, this will be zero.
363 */
364 extern unsigned long __clear_user(void __user *src, unsigned long size);
365
clear_user(char * src,unsigned long size)366 static inline unsigned long clear_user(char *src, unsigned long size)
367 {
368 if (access_ok(VERIFY_WRITE, src, size))
369 return __clear_user(src, size);
370
371 return -EFAULT;
372 }
373 /*
374 * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
375 * @dst: Destination address, in kernel space. This buffer must be at
376 * least @count bytes long.
377 * @src: Source address, in user space.
378 * @count: Maximum number of bytes to copy, including the trailing NUL.
379 *
380 * Copies a NUL-terminated string from userspace to kernel space.
381 * Caller must check the specified block with access_ok() before calling
382 * this function.
383 *
384 * On success, returns the length of the string (not including the trailing
385 * NUL).
386 *
387 * If access to userspace fails, returns -EFAULT (some data may have been
388 * copied).
389 *
390 * If @count is smaller than the length of the string, copies @count bytes
391 * and returns @count.
392 */
393 extern int __strncpy_from_user(char *dst, const char *src, long len);
394
strncpy_from_user(char * dst,const char * src,long len)395 static inline int strncpy_from_user(char *dst, const char *src, long len)
396 {
397 if (access_ok(VERIFY_READ, src, 1))
398 return __strncpy_from_user(dst, src, len);
399
400 return -EFAULT;
401 }
402
403 extern int __strlen_user(const char *src);
strlen_user(const char __user * src)404 static inline long strlen_user(const char __user *src)
405 {
406 return __strlen_user(src);
407 }
408
409 extern int __strnlen_user(const char *str, long len);
strnlen_user(const char __user * str,long len)410 static inline long strnlen_user(const char __user *str, long len)
411 {
412 if (!access_ok(VERIFY_READ, str, 0))
413 return 0;
414 else
415 return __strnlen_user(str, len);
416 }
417
418 struct exception_table_entry {
419 unsigned long insn;
420 unsigned long fixup;
421 };
422
423 extern int fixup_exception(struct pt_regs *regs);
424
425 #endif /* __SCORE_UACCESS_H */
426
427