Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * linux/fs/readdir.c | |
4 | * | |
5 | * Copyright (C) 1995 Linus Torvalds | |
6 | */ | |
7 | ||
85c9fe8f | 8 | #include <linux/stddef.h> |
022a1692 | 9 | #include <linux/kernel.h> |
630d9c47 | 10 | #include <linux/export.h> |
1da177e4 LT |
11 | #include <linux/time.h> |
12 | #include <linux/mm.h> | |
13 | #include <linux/errno.h> | |
14 | #include <linux/stat.h> | |
15 | #include <linux/file.h> | |
1da177e4 | 16 | #include <linux/fs.h> |
d4c7cf6c | 17 | #include <linux/fsnotify.h> |
1da177e4 LT |
18 | #include <linux/dirent.h> |
19 | #include <linux/security.h> | |
20 | #include <linux/syscalls.h> | |
21 | #include <linux/unistd.h> | |
0460b2a2 | 22 | #include <linux/compat.h> |
7c0f6ba6 | 23 | #include <linux/uaccess.h> |
1da177e4 | 24 | |
9f79b78e LT |
25 | #include <asm/unaligned.h> |
26 | ||
3e327154 LT |
27 | /* |
28 | * Some filesystems were never converted to '->iterate_shared()' | |
29 | * and their directory iterators want the inode lock held for | |
30 | * writing. This wrapper allows for converting from the shared | |
31 | * semantics to the exclusive inode use. | |
32 | */ | |
33 | int wrap_directory_iterator(struct file *file, | |
34 | struct dir_context *ctx, | |
35 | int (*iter)(struct file *, struct dir_context *)) | |
36 | { | |
37 | struct inode *inode = file_inode(file); | |
38 | int ret; | |
39 | ||
40 | /* | |
41 | * We'd love to have an 'inode_upgrade_trylock()' operation, | |
42 | * see the comment in mmap_upgrade_trylock() in mm/memory.c. | |
43 | * | |
44 | * But considering this is for "filesystems that never got | |
45 | * converted", it really doesn't matter. | |
46 | * | |
47 | * Also note that since we have to return with the lock held | |
48 | * for reading, we can't use the "killable()" locking here, | |
49 | * since we do need to get the lock even if we're dying. | |
50 | * | |
51 | * We could do the write part killably and then get the read | |
52 | * lock unconditionally if it mattered, but see above on why | |
53 | * this does the very simplistic conversion. | |
54 | */ | |
55 | up_read(&inode->i_rwsem); | |
56 | down_write(&inode->i_rwsem); | |
57 | ||
58 | /* | |
59 | * Since we dropped the inode lock, we should do the | |
60 | * DEADDIR test again. See 'iterate_dir()' below. | |
61 | * | |
62 | * Note that we don't need to re-do the f_pos games, | |
63 | * since the file must be locked wrt f_pos anyway. | |
64 | */ | |
65 | ret = -ENOENT; | |
66 | if (!IS_DEADDIR(inode)) | |
67 | ret = iter(file, ctx); | |
68 | ||
69 | downgrade_write(&inode->i_rwsem); | |
70 | return ret; | |
71 | } | |
72 | EXPORT_SYMBOL(wrap_directory_iterator); | |
73 | ||
9f79b78e LT |
74 | /* |
75 | * Note the "unsafe_put_user() semantics: we goto a | |
76 | * label for errors. | |
9f79b78e LT |
77 | */ |
78 | #define unsafe_copy_dirent_name(_dst, _src, _len, label) do { \ | |
79 | char __user *dst = (_dst); \ | |
80 | const char *src = (_src); \ | |
81 | size_t len = (_len); \ | |
c512c691 LT |
82 | unsafe_put_user(0, dst+len, label); \ |
83 | unsafe_copy_to_user(dst, src, len, label); \ | |
9f79b78e LT |
84 | } while (0) |
85 | ||
86 | ||
5c0ba4e0 | 87 | int iterate_dir(struct file *file, struct dir_context *ctx) |
1da177e4 | 88 | { |
496ad9aa | 89 | struct inode *inode = file_inode(file); |
1da177e4 | 90 | int res = -ENOTDIR; |
3e327154 LT |
91 | |
92 | if (!file->f_op->iterate_shared) | |
1da177e4 LT |
93 | goto out; |
94 | ||
95 | res = security_file_permission(file, MAY_READ); | |
96 | if (res) | |
97 | goto out; | |
98 | ||
d9e5d310 AG |
99 | res = fsnotify_file_perm(file, MAY_READ); |
100 | if (res) | |
101 | goto out; | |
102 | ||
3e327154 | 103 | res = down_read_killable(&inode->i_rwsem); |
0dc208b5 KT |
104 | if (res) |
105 | goto out; | |
da784511 | 106 | |
1da177e4 LT |
107 | res = -ENOENT; |
108 | if (!IS_DEADDIR(inode)) { | |
2233f31a | 109 | ctx->pos = file->f_pos; |
3e327154 | 110 | res = file->f_op->iterate_shared(file, ctx); |
2233f31a | 111 | file->f_pos = ctx->pos; |
d4c7cf6c | 112 | fsnotify_access(file); |
1da177e4 LT |
113 | file_accessed(file); |
114 | } | |
3e327154 | 115 | inode_unlock_shared(inode); |
1da177e4 LT |
116 | out: |
117 | return res; | |
118 | } | |
5c0ba4e0 | 119 | EXPORT_SYMBOL(iterate_dir); |
1da177e4 | 120 | |
8a23eb80 LT |
121 | /* |
122 | * POSIX says that a dirent name cannot contain NULL or a '/'. | |
123 | * | |
124 | * It's not 100% clear what we should really do in this case. | |
125 | * The filesystem is clearly corrupted, but returning a hard | |
126 | * error means that you now don't see any of the other names | |
127 | * either, so that isn't a perfect alternative. | |
128 | * | |
129 | * And if you return an error, what error do you use? Several | |
130 | * filesystems seem to have decided on EUCLEAN being the error | |
131 | * code for EFSCORRUPTED, and that may be the error to use. Or | |
132 | * just EIO, which is perhaps more obvious to users. | |
133 | * | |
134 | * In order to see the other file names in the directory, the | |
135 | * caller might want to make this a "soft" error: skip the | |
136 | * entry, and return the error at the end instead. | |
137 | * | |
138 | * Note that this should likely do a "memchr(name, 0, len)" | |
139 | * check too, since that would be filesystem corruption as | |
140 | * well. However, that case can't actually confuse user space, | |
141 | * which has to do a strlen() on the name anyway to find the | |
142 | * filename length, and the above "soft error" worry means | |
143 | * that it's probably better left alone until we have that | |
144 | * issue clarified. | |
2c6b7bcd LT |
145 | * |
146 | * Note the PATH_MAX check - it's arbitrary but the real | |
147 | * kernel limit on a possible path component, not NAME_MAX, | |
148 | * which is the technical standard limit. | |
8a23eb80 LT |
149 | */ |
150 | static int verify_dirent_name(const char *name, int len) | |
151 | { | |
2c6b7bcd | 152 | if (len <= 0 || len >= PATH_MAX) |
8a23eb80 | 153 | return -EIO; |
b9959c7a | 154 | if (memchr(name, '/', len)) |
8a23eb80 LT |
155 | return -EIO; |
156 | return 0; | |
157 | } | |
158 | ||
1da177e4 LT |
159 | /* |
160 | * Traditional linux readdir() handling.. | |
161 | * | |
162 | * "count=1" is a special case, meaning that the buffer is one | |
163 | * dirent-structure in size and that the code can't handle more | |
164 | * anyway. Thus the special "fillonedir()" function for that | |
165 | * case (the low-level handlers don't need to care about this). | |
166 | */ | |
1da177e4 LT |
167 | |
168 | #ifdef __ARCH_WANT_OLD_READDIR | |
169 | ||
170 | struct old_linux_dirent { | |
171 | unsigned long d_ino; | |
172 | unsigned long d_offset; | |
173 | unsigned short d_namlen; | |
2507135e | 174 | char d_name[]; |
1da177e4 LT |
175 | }; |
176 | ||
177 | struct readdir_callback { | |
5c0ba4e0 | 178 | struct dir_context ctx; |
1da177e4 LT |
179 | struct old_linux_dirent __user * dirent; |
180 | int result; | |
181 | }; | |
182 | ||
25885a35 | 183 | static bool fillonedir(struct dir_context *ctx, const char *name, int namlen, |
ac7576f4 | 184 | loff_t offset, u64 ino, unsigned int d_type) |
1da177e4 | 185 | { |
ac7576f4 MS |
186 | struct readdir_callback *buf = |
187 | container_of(ctx, struct readdir_callback, ctx); | |
1da177e4 | 188 | struct old_linux_dirent __user * dirent; |
afefdbb2 | 189 | unsigned long d_ino; |
1da177e4 LT |
190 | |
191 | if (buf->result) | |
25885a35 | 192 | return false; |
0c93ac69 | 193 | buf->result = verify_dirent_name(name, namlen); |
25885a35 AV |
194 | if (buf->result) |
195 | return false; | |
afefdbb2 | 196 | d_ino = ino; |
8f3f655d AV |
197 | if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { |
198 | buf->result = -EOVERFLOW; | |
25885a35 | 199 | return false; |
8f3f655d | 200 | } |
1da177e4 LT |
201 | buf->result++; |
202 | dirent = buf->dirent; | |
391b7461 | 203 | if (!user_write_access_begin(dirent, |
1da177e4 LT |
204 | (unsigned long)(dirent->d_name + namlen + 1) - |
205 | (unsigned long)dirent)) | |
206 | goto efault; | |
391b7461 AV |
207 | unsafe_put_user(d_ino, &dirent->d_ino, efault_end); |
208 | unsafe_put_user(offset, &dirent->d_offset, efault_end); | |
209 | unsafe_put_user(namlen, &dirent->d_namlen, efault_end); | |
210 | unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); | |
211 | user_write_access_end(); | |
25885a35 | 212 | return true; |
391b7461 AV |
213 | efault_end: |
214 | user_write_access_end(); | |
1da177e4 LT |
215 | efault: |
216 | buf->result = -EFAULT; | |
25885a35 | 217 | return false; |
1da177e4 LT |
218 | } |
219 | ||
d4e82042 HC |
220 | SYSCALL_DEFINE3(old_readdir, unsigned int, fd, |
221 | struct old_linux_dirent __user *, dirent, unsigned int, count) | |
1da177e4 LT |
222 | { |
223 | int error; | |
63b6df14 | 224 | struct fd f = fdget_pos(fd); |
ac6614b7 AV |
225 | struct readdir_callback buf = { |
226 | .ctx.actor = fillonedir, | |
227 | .dirent = dirent | |
228 | }; | |
1da177e4 | 229 | |
2903ff01 | 230 | if (!f.file) |
863ced7f | 231 | return -EBADF; |
1da177e4 | 232 | |
5c0ba4e0 | 233 | error = iterate_dir(f.file, &buf.ctx); |
53c9c5c0 | 234 | if (buf.result) |
1da177e4 LT |
235 | error = buf.result; |
236 | ||
63b6df14 | 237 | fdput_pos(f); |
1da177e4 LT |
238 | return error; |
239 | } | |
240 | ||
241 | #endif /* __ARCH_WANT_OLD_READDIR */ | |
242 | ||
243 | /* | |
244 | * New, all-improved, singing, dancing, iBCS2-compliant getdents() | |
245 | * interface. | |
246 | */ | |
247 | struct linux_dirent { | |
248 | unsigned long d_ino; | |
249 | unsigned long d_off; | |
250 | unsigned short d_reclen; | |
2507135e | 251 | char d_name[]; |
1da177e4 LT |
252 | }; |
253 | ||
254 | struct getdents_callback { | |
5c0ba4e0 | 255 | struct dir_context ctx; |
1da177e4 | 256 | struct linux_dirent __user * current_dir; |
3c2659bd | 257 | int prev_reclen; |
1da177e4 LT |
258 | int count; |
259 | int error; | |
260 | }; | |
261 | ||
25885a35 | 262 | static bool filldir(struct dir_context *ctx, const char *name, int namlen, |
ac7576f4 | 263 | loff_t offset, u64 ino, unsigned int d_type) |
1da177e4 | 264 | { |
3c2659bd | 265 | struct linux_dirent __user *dirent, *prev; |
ac7576f4 MS |
266 | struct getdents_callback *buf = |
267 | container_of(ctx, struct getdents_callback, ctx); | |
afefdbb2 | 268 | unsigned long d_ino; |
85c9fe8f KW |
269 | int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2, |
270 | sizeof(long)); | |
3c2659bd | 271 | int prev_reclen; |
1da177e4 | 272 | |
8a23eb80 LT |
273 | buf->error = verify_dirent_name(name, namlen); |
274 | if (unlikely(buf->error)) | |
25885a35 | 275 | return false; |
1da177e4 LT |
276 | buf->error = -EINVAL; /* only used if we fail.. */ |
277 | if (reclen > buf->count) | |
25885a35 | 278 | return false; |
afefdbb2 | 279 | d_ino = ino; |
8f3f655d AV |
280 | if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { |
281 | buf->error = -EOVERFLOW; | |
25885a35 | 282 | return false; |
8f3f655d | 283 | } |
3c2659bd LT |
284 | prev_reclen = buf->prev_reclen; |
285 | if (prev_reclen && signal_pending(current)) | |
25885a35 | 286 | return false; |
9f79b78e | 287 | dirent = buf->current_dir; |
3c2659bd | 288 | prev = (void __user *) dirent - prev_reclen; |
41cd7805 | 289 | if (!user_write_access_begin(prev, reclen + prev_reclen)) |
3c2659bd LT |
290 | goto efault; |
291 | ||
292 | /* This might be 'dirent->d_off', but if so it will get overwritten */ | |
293 | unsafe_put_user(offset, &prev->d_off, efault_end); | |
9f79b78e LT |
294 | unsafe_put_user(d_ino, &dirent->d_ino, efault_end); |
295 | unsafe_put_user(reclen, &dirent->d_reclen, efault_end); | |
296 | unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end); | |
297 | unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); | |
41cd7805 | 298 | user_write_access_end(); |
9f79b78e | 299 | |
3c2659bd LT |
300 | buf->current_dir = (void __user *)dirent + reclen; |
301 | buf->prev_reclen = reclen; | |
1da177e4 | 302 | buf->count -= reclen; |
25885a35 | 303 | return true; |
9f79b78e | 304 | efault_end: |
41cd7805 | 305 | user_write_access_end(); |
1da177e4 LT |
306 | efault: |
307 | buf->error = -EFAULT; | |
25885a35 | 308 | return false; |
1da177e4 LT |
309 | } |
310 | ||
20f37034 HC |
311 | SYSCALL_DEFINE3(getdents, unsigned int, fd, |
312 | struct linux_dirent __user *, dirent, unsigned int, count) | |
1da177e4 | 313 | { |
2903ff01 | 314 | struct fd f; |
ac6614b7 AV |
315 | struct getdents_callback buf = { |
316 | .ctx.actor = filldir, | |
317 | .count = count, | |
318 | .current_dir = dirent | |
319 | }; | |
1da177e4 LT |
320 | int error; |
321 | ||
63b6df14 | 322 | f = fdget_pos(fd); |
2903ff01 | 323 | if (!f.file) |
863ced7f | 324 | return -EBADF; |
1da177e4 | 325 | |
5c0ba4e0 | 326 | error = iterate_dir(f.file, &buf.ctx); |
53c9c5c0 AV |
327 | if (error >= 0) |
328 | error = buf.error; | |
3c2659bd LT |
329 | if (buf.prev_reclen) { |
330 | struct linux_dirent __user * lastdirent; | |
331 | lastdirent = (void __user *)buf.current_dir - buf.prev_reclen; | |
332 | ||
bb6f619b | 333 | if (put_user(buf.ctx.pos, &lastdirent->d_off)) |
1da177e4 LT |
334 | error = -EFAULT; |
335 | else | |
336 | error = count - buf.count; | |
337 | } | |
63b6df14 | 338 | fdput_pos(f); |
1da177e4 LT |
339 | return error; |
340 | } | |
341 | ||
1da177e4 | 342 | struct getdents_callback64 { |
5c0ba4e0 | 343 | struct dir_context ctx; |
1da177e4 | 344 | struct linux_dirent64 __user * current_dir; |
3c2659bd | 345 | int prev_reclen; |
1da177e4 LT |
346 | int count; |
347 | int error; | |
348 | }; | |
349 | ||
25885a35 | 350 | static bool filldir64(struct dir_context *ctx, const char *name, int namlen, |
ac7576f4 | 351 | loff_t offset, u64 ino, unsigned int d_type) |
1da177e4 | 352 | { |
3c2659bd | 353 | struct linux_dirent64 __user *dirent, *prev; |
ac7576f4 MS |
354 | struct getdents_callback64 *buf = |
355 | container_of(ctx, struct getdents_callback64, ctx); | |
85c9fe8f KW |
356 | int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1, |
357 | sizeof(u64)); | |
3c2659bd | 358 | int prev_reclen; |
1da177e4 | 359 | |
8a23eb80 LT |
360 | buf->error = verify_dirent_name(name, namlen); |
361 | if (unlikely(buf->error)) | |
25885a35 | 362 | return false; |
1da177e4 LT |
363 | buf->error = -EINVAL; /* only used if we fail.. */ |
364 | if (reclen > buf->count) | |
25885a35 | 365 | return false; |
3c2659bd LT |
366 | prev_reclen = buf->prev_reclen; |
367 | if (prev_reclen && signal_pending(current)) | |
25885a35 | 368 | return false; |
9f79b78e | 369 | dirent = buf->current_dir; |
3c2659bd | 370 | prev = (void __user *)dirent - prev_reclen; |
41cd7805 | 371 | if (!user_write_access_begin(prev, reclen + prev_reclen)) |
3c2659bd LT |
372 | goto efault; |
373 | ||
374 | /* This might be 'dirent->d_off', but if so it will get overwritten */ | |
375 | unsafe_put_user(offset, &prev->d_off, efault_end); | |
9f79b78e LT |
376 | unsafe_put_user(ino, &dirent->d_ino, efault_end); |
377 | unsafe_put_user(reclen, &dirent->d_reclen, efault_end); | |
378 | unsafe_put_user(d_type, &dirent->d_type, efault_end); | |
379 | unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); | |
41cd7805 | 380 | user_write_access_end(); |
9f79b78e | 381 | |
3c2659bd LT |
382 | buf->prev_reclen = reclen; |
383 | buf->current_dir = (void __user *)dirent + reclen; | |
1da177e4 | 384 | buf->count -= reclen; |
25885a35 | 385 | return true; |
3c2659bd | 386 | |
9f79b78e | 387 | efault_end: |
41cd7805 | 388 | user_write_access_end(); |
1da177e4 LT |
389 | efault: |
390 | buf->error = -EFAULT; | |
25885a35 | 391 | return false; |
1da177e4 LT |
392 | } |
393 | ||
fb2da16c CH |
394 | SYSCALL_DEFINE3(getdents64, unsigned int, fd, |
395 | struct linux_dirent64 __user *, dirent, unsigned int, count) | |
1da177e4 | 396 | { |
2903ff01 | 397 | struct fd f; |
ac6614b7 AV |
398 | struct getdents_callback64 buf = { |
399 | .ctx.actor = filldir64, | |
400 | .count = count, | |
401 | .current_dir = dirent | |
402 | }; | |
1da177e4 LT |
403 | int error; |
404 | ||
63b6df14 | 405 | f = fdget_pos(fd); |
2903ff01 | 406 | if (!f.file) |
863ced7f | 407 | return -EBADF; |
1da177e4 | 408 | |
5c0ba4e0 | 409 | error = iterate_dir(f.file, &buf.ctx); |
53c9c5c0 AV |
410 | if (error >= 0) |
411 | error = buf.error; | |
3c2659bd LT |
412 | if (buf.prev_reclen) { |
413 | struct linux_dirent64 __user * lastdirent; | |
bb6f619b | 414 | typeof(lastdirent->d_off) d_off = buf.ctx.pos; |
3c2659bd LT |
415 | |
416 | lastdirent = (void __user *) buf.current_dir - buf.prev_reclen; | |
5fb15141 | 417 | if (put_user(d_off, &lastdirent->d_off)) |
53c9c5c0 AV |
418 | error = -EFAULT; |
419 | else | |
420 | error = count - buf.count; | |
1da177e4 | 421 | } |
63b6df14 | 422 | fdput_pos(f); |
1da177e4 LT |
423 | return error; |
424 | } | |
0460b2a2 AV |
425 | |
426 | #ifdef CONFIG_COMPAT | |
427 | struct compat_old_linux_dirent { | |
428 | compat_ulong_t d_ino; | |
429 | compat_ulong_t d_offset; | |
430 | unsigned short d_namlen; | |
2507135e | 431 | char d_name[]; |
0460b2a2 AV |
432 | }; |
433 | ||
434 | struct compat_readdir_callback { | |
435 | struct dir_context ctx; | |
436 | struct compat_old_linux_dirent __user *dirent; | |
437 | int result; | |
438 | }; | |
439 | ||
25885a35 | 440 | static bool compat_fillonedir(struct dir_context *ctx, const char *name, |
0460b2a2 AV |
441 | int namlen, loff_t offset, u64 ino, |
442 | unsigned int d_type) | |
443 | { | |
444 | struct compat_readdir_callback *buf = | |
445 | container_of(ctx, struct compat_readdir_callback, ctx); | |
446 | struct compat_old_linux_dirent __user *dirent; | |
447 | compat_ulong_t d_ino; | |
448 | ||
449 | if (buf->result) | |
25885a35 | 450 | return false; |
0c93ac69 | 451 | buf->result = verify_dirent_name(name, namlen); |
25885a35 AV |
452 | if (buf->result) |
453 | return false; | |
0460b2a2 AV |
454 | d_ino = ino; |
455 | if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { | |
456 | buf->result = -EOVERFLOW; | |
25885a35 | 457 | return false; |
0460b2a2 AV |
458 | } |
459 | buf->result++; | |
460 | dirent = buf->dirent; | |
391b7461 | 461 | if (!user_write_access_begin(dirent, |
0460b2a2 AV |
462 | (unsigned long)(dirent->d_name + namlen + 1) - |
463 | (unsigned long)dirent)) | |
464 | goto efault; | |
391b7461 AV |
465 | unsafe_put_user(d_ino, &dirent->d_ino, efault_end); |
466 | unsafe_put_user(offset, &dirent->d_offset, efault_end); | |
467 | unsafe_put_user(namlen, &dirent->d_namlen, efault_end); | |
468 | unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); | |
469 | user_write_access_end(); | |
25885a35 | 470 | return true; |
391b7461 AV |
471 | efault_end: |
472 | user_write_access_end(); | |
0460b2a2 AV |
473 | efault: |
474 | buf->result = -EFAULT; | |
25885a35 | 475 | return false; |
0460b2a2 AV |
476 | } |
477 | ||
478 | COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd, | |
479 | struct compat_old_linux_dirent __user *, dirent, unsigned int, count) | |
480 | { | |
481 | int error; | |
482 | struct fd f = fdget_pos(fd); | |
483 | struct compat_readdir_callback buf = { | |
484 | .ctx.actor = compat_fillonedir, | |
485 | .dirent = dirent | |
486 | }; | |
487 | ||
488 | if (!f.file) | |
489 | return -EBADF; | |
490 | ||
491 | error = iterate_dir(f.file, &buf.ctx); | |
492 | if (buf.result) | |
493 | error = buf.result; | |
494 | ||
495 | fdput_pos(f); | |
496 | return error; | |
497 | } | |
498 | ||
499 | struct compat_linux_dirent { | |
500 | compat_ulong_t d_ino; | |
501 | compat_ulong_t d_off; | |
502 | unsigned short d_reclen; | |
2507135e | 503 | char d_name[]; |
0460b2a2 AV |
504 | }; |
505 | ||
506 | struct compat_getdents_callback { | |
507 | struct dir_context ctx; | |
508 | struct compat_linux_dirent __user *current_dir; | |
82af599b | 509 | int prev_reclen; |
0460b2a2 AV |
510 | int count; |
511 | int error; | |
512 | }; | |
513 | ||
25885a35 | 514 | static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen, |
0460b2a2 AV |
515 | loff_t offset, u64 ino, unsigned int d_type) |
516 | { | |
82af599b | 517 | struct compat_linux_dirent __user *dirent, *prev; |
0460b2a2 AV |
518 | struct compat_getdents_callback *buf = |
519 | container_of(ctx, struct compat_getdents_callback, ctx); | |
520 | compat_ulong_t d_ino; | |
521 | int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) + | |
522 | namlen + 2, sizeof(compat_long_t)); | |
82af599b | 523 | int prev_reclen; |
0460b2a2 | 524 | |
82af599b AV |
525 | buf->error = verify_dirent_name(name, namlen); |
526 | if (unlikely(buf->error)) | |
25885a35 | 527 | return false; |
0460b2a2 AV |
528 | buf->error = -EINVAL; /* only used if we fail.. */ |
529 | if (reclen > buf->count) | |
25885a35 | 530 | return false; |
0460b2a2 AV |
531 | d_ino = ino; |
532 | if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { | |
533 | buf->error = -EOVERFLOW; | |
25885a35 | 534 | return false; |
0460b2a2 | 535 | } |
82af599b AV |
536 | prev_reclen = buf->prev_reclen; |
537 | if (prev_reclen && signal_pending(current)) | |
25885a35 | 538 | return false; |
0460b2a2 | 539 | dirent = buf->current_dir; |
82af599b AV |
540 | prev = (void __user *) dirent - prev_reclen; |
541 | if (!user_write_access_begin(prev, reclen + prev_reclen)) | |
0460b2a2 | 542 | goto efault; |
82af599b AV |
543 | |
544 | unsafe_put_user(offset, &prev->d_off, efault_end); | |
545 | unsafe_put_user(d_ino, &dirent->d_ino, efault_end); | |
546 | unsafe_put_user(reclen, &dirent->d_reclen, efault_end); | |
547 | unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end); | |
548 | unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); | |
549 | user_write_access_end(); | |
550 | ||
551 | buf->prev_reclen = reclen; | |
552 | buf->current_dir = (void __user *)dirent + reclen; | |
0460b2a2 | 553 | buf->count -= reclen; |
25885a35 | 554 | return true; |
82af599b AV |
555 | efault_end: |
556 | user_write_access_end(); | |
0460b2a2 AV |
557 | efault: |
558 | buf->error = -EFAULT; | |
25885a35 | 559 | return false; |
0460b2a2 AV |
560 | } |
561 | ||
562 | COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd, | |
563 | struct compat_linux_dirent __user *, dirent, unsigned int, count) | |
564 | { | |
565 | struct fd f; | |
0460b2a2 AV |
566 | struct compat_getdents_callback buf = { |
567 | .ctx.actor = compat_filldir, | |
568 | .current_dir = dirent, | |
569 | .count = count | |
570 | }; | |
571 | int error; | |
572 | ||
0460b2a2 AV |
573 | f = fdget_pos(fd); |
574 | if (!f.file) | |
575 | return -EBADF; | |
576 | ||
577 | error = iterate_dir(f.file, &buf.ctx); | |
578 | if (error >= 0) | |
579 | error = buf.error; | |
82af599b AV |
580 | if (buf.prev_reclen) { |
581 | struct compat_linux_dirent __user * lastdirent; | |
582 | lastdirent = (void __user *)buf.current_dir - buf.prev_reclen; | |
583 | ||
0460b2a2 AV |
584 | if (put_user(buf.ctx.pos, &lastdirent->d_off)) |
585 | error = -EFAULT; | |
586 | else | |
587 | error = count - buf.count; | |
588 | } | |
589 | fdput_pos(f); | |
590 | return error; | |
591 | } | |
592 | #endif |