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1/*
2 * linux/fs/readdir.c
3 *
4 * Copyright (C) 1995 Linus Torvalds
5 */
6
7#include <linux/stddef.h>
8#include <linux/kernel.h>
9#include <linux/export.h>
10#include <linux/time.h>
11#include <linux/mm.h>
12#include <linux/errno.h>
13#include <linux/stat.h>
14#include <linux/file.h>
15#include <linux/fs.h>
16#include <linux/dirent.h>
17#include <linux/security.h>
18#include <linux/syscalls.h>
19#include <linux/unistd.h>
20
21#include <asm/uaccess.h>
22
23int iterate_dir(struct file *file, struct dir_context *ctx)
24{
25 struct inode *inode = file_inode(file);
26 int res = -ENOTDIR;
27 if (!file->f_op->iterate)
28 goto out;
29
30 res = security_file_permission(file, MAY_READ);
31 if (res)
32 goto out;
33
34 res = mutex_lock_killable(&inode->i_mutex);
35 if (res)
36 goto out;
37
38 res = -ENOENT;
39 if (!IS_DEADDIR(inode)) {
40 ctx->pos = file->f_pos;
41 res = file->f_op->iterate(file, ctx);
42 file->f_pos = ctx->pos;
43 file_accessed(file);
44 }
45 mutex_unlock(&inode->i_mutex);
46out:
47 return res;
48}
49EXPORT_SYMBOL(iterate_dir);
50
51/*
52 * Traditional linux readdir() handling..
53 *
54 * "count=1" is a special case, meaning that the buffer is one
55 * dirent-structure in size and that the code can't handle more
56 * anyway. Thus the special "fillonedir()" function for that
57 * case (the low-level handlers don't need to care about this).
58 */
59
60#ifdef __ARCH_WANT_OLD_READDIR
61
62struct old_linux_dirent {
63 unsigned long d_ino;
64 unsigned long d_offset;
65 unsigned short d_namlen;
66 char d_name[1];
67};
68
69struct readdir_callback {
70 struct dir_context ctx;
71 struct old_linux_dirent __user * dirent;
72 int result;
73};
74
75static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,
76 u64 ino, unsigned int d_type)
77{
78 struct readdir_callback *buf = (struct readdir_callback *) __buf;
79 struct old_linux_dirent __user * dirent;
80 unsigned long d_ino;
81
82 if (buf->result)
83 return -EINVAL;
84 d_ino = ino;
85 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
86 buf->result = -EOVERFLOW;
87 return -EOVERFLOW;
88 }
89 buf->result++;
90 dirent = buf->dirent;
91 if (!access_ok(VERIFY_WRITE, dirent,
92 (unsigned long)(dirent->d_name + namlen + 1) -
93 (unsigned long)dirent))
94 goto efault;
95 if ( __put_user(d_ino, &dirent->d_ino) ||
96 __put_user(offset, &dirent->d_offset) ||
97 __put_user(namlen, &dirent->d_namlen) ||
98 __copy_to_user(dirent->d_name, name, namlen) ||
99 __put_user(0, dirent->d_name + namlen))
100 goto efault;
101 return 0;
102efault:
103 buf->result = -EFAULT;
104 return -EFAULT;
105}
106
107SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
108 struct old_linux_dirent __user *, dirent, unsigned int, count)
109{
110 int error;
111 struct fd f = fdget(fd);
112 struct readdir_callback buf = {
113 .ctx.actor = fillonedir,
114 .dirent = dirent
115 };
116
117 if (!f.file)
118 return -EBADF;
119
120 error = iterate_dir(f.file, &buf.ctx);
121 if (buf.result)
122 error = buf.result;
123
124 fdput(f);
125 return error;
126}
127
128#endif /* __ARCH_WANT_OLD_READDIR */
129
130/*
131 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
132 * interface.
133 */
134struct linux_dirent {
135 unsigned long d_ino;
136 unsigned long d_off;
137 unsigned short d_reclen;
138 char d_name[1];
139};
140
141struct getdents_callback {
142 struct dir_context ctx;
143 struct linux_dirent __user * current_dir;
144 struct linux_dirent __user * previous;
145 int count;
146 int error;
147};
148
149static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
150 u64 ino, unsigned int d_type)
151{
152 struct linux_dirent __user * dirent;
153 struct getdents_callback * buf = (struct getdents_callback *) __buf;
154 unsigned long d_ino;
155 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
156 sizeof(long));
157
158 buf->error = -EINVAL; /* only used if we fail.. */
159 if (reclen > buf->count)
160 return -EINVAL;
161 d_ino = ino;
162 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
163 buf->error = -EOVERFLOW;
164 return -EOVERFLOW;
165 }
166 dirent = buf->previous;
167 if (dirent) {
168 if (__put_user(offset, &dirent->d_off))
169 goto efault;
170 }
171 dirent = buf->current_dir;
172 if (__put_user(d_ino, &dirent->d_ino))
173 goto efault;
174 if (__put_user(reclen, &dirent->d_reclen))
175 goto efault;
176 if (copy_to_user(dirent->d_name, name, namlen))
177 goto efault;
178 if (__put_user(0, dirent->d_name + namlen))
179 goto efault;
180 if (__put_user(d_type, (char __user *) dirent + reclen - 1))
181 goto efault;
182 buf->previous = dirent;
183 dirent = (void __user *)dirent + reclen;
184 buf->current_dir = dirent;
185 buf->count -= reclen;
186 return 0;
187efault:
188 buf->error = -EFAULT;
189 return -EFAULT;
190}
191
192SYSCALL_DEFINE3(getdents, unsigned int, fd,
193 struct linux_dirent __user *, dirent, unsigned int, count)
194{
195 struct fd f;
196 struct linux_dirent __user * lastdirent;
197 struct getdents_callback buf = {
198 .ctx.actor = filldir,
199 .count = count,
200 .current_dir = dirent
201 };
202 int error;
203
204 if (!access_ok(VERIFY_WRITE, dirent, count))
205 return -EFAULT;
206
207 f = fdget(fd);
208 if (!f.file)
209 return -EBADF;
210
211 error = iterate_dir(f.file, &buf.ctx);
212 if (error >= 0)
213 error = buf.error;
214 lastdirent = buf.previous;
215 if (lastdirent) {
216 if (put_user(buf.ctx.pos, &lastdirent->d_off))
217 error = -EFAULT;
218 else
219 error = count - buf.count;
220 }
221 fdput(f);
222 return error;
223}
224
225struct getdents_callback64 {
226 struct dir_context ctx;
227 struct linux_dirent64 __user * current_dir;
228 struct linux_dirent64 __user * previous;
229 int count;
230 int error;
231};
232
233static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
234 u64 ino, unsigned int d_type)
235{
236 struct linux_dirent64 __user *dirent;
237 struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
238 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
239 sizeof(u64));
240
241 buf->error = -EINVAL; /* only used if we fail.. */
242 if (reclen > buf->count)
243 return -EINVAL;
244 dirent = buf->previous;
245 if (dirent) {
246 if (__put_user(offset, &dirent->d_off))
247 goto efault;
248 }
249 dirent = buf->current_dir;
250 if (__put_user(ino, &dirent->d_ino))
251 goto efault;
252 if (__put_user(0, &dirent->d_off))
253 goto efault;
254 if (__put_user(reclen, &dirent->d_reclen))
255 goto efault;
256 if (__put_user(d_type, &dirent->d_type))
257 goto efault;
258 if (copy_to_user(dirent->d_name, name, namlen))
259 goto efault;
260 if (__put_user(0, dirent->d_name + namlen))
261 goto efault;
262 buf->previous = dirent;
263 dirent = (void __user *)dirent + reclen;
264 buf->current_dir = dirent;
265 buf->count -= reclen;
266 return 0;
267efault:
268 buf->error = -EFAULT;
269 return -EFAULT;
270}
271
272SYSCALL_DEFINE3(getdents64, unsigned int, fd,
273 struct linux_dirent64 __user *, dirent, unsigned int, count)
274{
275 struct fd f;
276 struct linux_dirent64 __user * lastdirent;
277 struct getdents_callback64 buf = {
278 .ctx.actor = filldir64,
279 .count = count,
280 .current_dir = dirent
281 };
282 int error;
283
284 if (!access_ok(VERIFY_WRITE, dirent, count))
285 return -EFAULT;
286
287 f = fdget(fd);
288 if (!f.file)
289 return -EBADF;
290
291 error = iterate_dir(f.file, &buf.ctx);
292 if (error >= 0)
293 error = buf.error;
294 lastdirent = buf.previous;
295 if (lastdirent) {
296 typeof(lastdirent->d_off) d_off = buf.ctx.pos;
297 if (__put_user(d_off, &lastdirent->d_off))
298 error = -EFAULT;
299 else
300 error = count - buf.count;
301 }
302 fdput(f);
303 return error;
304}
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