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