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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/fsnotify.h>
17#include <linux/dirent.h>
18#include <linux/security.h>
19#include <linux/syscalls.h>
20#include <linux/unistd.h>
21
22#include <linux/uaccess.h>
23
24int iterate_dir(struct file *file, struct dir_context *ctx)
25{
26 struct inode *inode = file_inode(file);
27 bool shared = false;
28 int res = -ENOTDIR;
29 if (file->f_op->iterate_shared)
30 shared = true;
31 else if (!file->f_op->iterate)
32 goto out;
33
34 res = security_file_permission(file, MAY_READ);
35 if (res)
36 goto out;
37
38 if (shared) {
39 inode_lock_shared(inode);
40 } else {
41 res = down_write_killable(&inode->i_rwsem);
42 if (res)
43 goto out;
44 }
45
46 res = -ENOENT;
47 if (!IS_DEADDIR(inode)) {
48 ctx->pos = file->f_pos;
49 if (shared)
50 res = file->f_op->iterate_shared(file, ctx);
51 else
52 res = file->f_op->iterate(file, ctx);
53 file->f_pos = ctx->pos;
54 fsnotify_access(file);
55 file_accessed(file);
56 }
57 if (shared)
58 inode_unlock_shared(inode);
59 else
60 inode_unlock(inode);
61out:
62 return res;
63}
64EXPORT_SYMBOL(iterate_dir);
65
66/*
67 * Traditional linux readdir() handling..
68 *
69 * "count=1" is a special case, meaning that the buffer is one
70 * dirent-structure in size and that the code can't handle more
71 * anyway. Thus the special "fillonedir()" function for that
72 * case (the low-level handlers don't need to care about this).
73 */
74
75#ifdef __ARCH_WANT_OLD_READDIR
76
77struct old_linux_dirent {
78 unsigned long d_ino;
79 unsigned long d_offset;
80 unsigned short d_namlen;
81 char d_name[1];
82};
83
84struct readdir_callback {
85 struct dir_context ctx;
86 struct old_linux_dirent __user * dirent;
87 int result;
88};
89
90static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
91 loff_t offset, u64 ino, unsigned int d_type)
92{
93 struct readdir_callback *buf =
94 container_of(ctx, struct readdir_callback, ctx);
95 struct old_linux_dirent __user * dirent;
96 unsigned long d_ino;
97
98 if (buf->result)
99 return -EINVAL;
100 d_ino = ino;
101 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
102 buf->result = -EOVERFLOW;
103 return -EOVERFLOW;
104 }
105 buf->result++;
106 dirent = buf->dirent;
107 if (!access_ok(VERIFY_WRITE, dirent,
108 (unsigned long)(dirent->d_name + namlen + 1) -
109 (unsigned long)dirent))
110 goto efault;
111 if ( __put_user(d_ino, &dirent->d_ino) ||
112 __put_user(offset, &dirent->d_offset) ||
113 __put_user(namlen, &dirent->d_namlen) ||
114 __copy_to_user(dirent->d_name, name, namlen) ||
115 __put_user(0, dirent->d_name + namlen))
116 goto efault;
117 return 0;
118efault:
119 buf->result = -EFAULT;
120 return -EFAULT;
121}
122
123SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
124 struct old_linux_dirent __user *, dirent, unsigned int, count)
125{
126 int error;
127 struct fd f = fdget_pos(fd);
128 struct readdir_callback buf = {
129 .ctx.actor = fillonedir,
130 .dirent = dirent
131 };
132
133 if (!f.file)
134 return -EBADF;
135
136 error = iterate_dir(f.file, &buf.ctx);
137 if (buf.result)
138 error = buf.result;
139
140 fdput_pos(f);
141 return error;
142}
143
144#endif /* __ARCH_WANT_OLD_READDIR */
145
146/*
147 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
148 * interface.
149 */
150struct linux_dirent {
151 unsigned long d_ino;
152 unsigned long d_off;
153 unsigned short d_reclen;
154 char d_name[1];
155};
156
157struct getdents_callback {
158 struct dir_context ctx;
159 struct linux_dirent __user * current_dir;
160 struct linux_dirent __user * previous;
161 int count;
162 int error;
163};
164
165static int filldir(struct dir_context *ctx, const char *name, int namlen,
166 loff_t offset, u64 ino, unsigned int d_type)
167{
168 struct linux_dirent __user * dirent;
169 struct getdents_callback *buf =
170 container_of(ctx, struct getdents_callback, ctx);
171 unsigned long d_ino;
172 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
173 sizeof(long));
174
175 buf->error = -EINVAL; /* only used if we fail.. */
176 if (reclen > buf->count)
177 return -EINVAL;
178 d_ino = ino;
179 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
180 buf->error = -EOVERFLOW;
181 return -EOVERFLOW;
182 }
183 dirent = buf->previous;
184 if (dirent) {
185 if (signal_pending(current))
186 return -EINTR;
187 if (__put_user(offset, &dirent->d_off))
188 goto efault;
189 }
190 dirent = buf->current_dir;
191 if (__put_user(d_ino, &dirent->d_ino))
192 goto efault;
193 if (__put_user(reclen, &dirent->d_reclen))
194 goto efault;
195 if (copy_to_user(dirent->d_name, name, namlen))
196 goto efault;
197 if (__put_user(0, dirent->d_name + namlen))
198 goto efault;
199 if (__put_user(d_type, (char __user *) dirent + reclen - 1))
200 goto efault;
201 buf->previous = dirent;
202 dirent = (void __user *)dirent + reclen;
203 buf->current_dir = dirent;
204 buf->count -= reclen;
205 return 0;
206efault:
207 buf->error = -EFAULT;
208 return -EFAULT;
209}
210
211SYSCALL_DEFINE3(getdents, unsigned int, fd,
212 struct linux_dirent __user *, dirent, unsigned int, count)
213{
214 struct fd f;
215 struct linux_dirent __user * lastdirent;
216 struct getdents_callback buf = {
217 .ctx.actor = filldir,
218 .count = count,
219 .current_dir = dirent
220 };
221 int error;
222
223 if (!access_ok(VERIFY_WRITE, dirent, count))
224 return -EFAULT;
225
226 f = fdget_pos(fd);
227 if (!f.file)
228 return -EBADF;
229
230 error = iterate_dir(f.file, &buf.ctx);
231 if (error >= 0)
232 error = buf.error;
233 lastdirent = buf.previous;
234 if (lastdirent) {
235 if (put_user(buf.ctx.pos, &lastdirent->d_off))
236 error = -EFAULT;
237 else
238 error = count - buf.count;
239 }
240 fdput_pos(f);
241 return error;
242}
243
244struct getdents_callback64 {
245 struct dir_context ctx;
246 struct linux_dirent64 __user * current_dir;
247 struct linux_dirent64 __user * previous;
248 int count;
249 int error;
250};
251
252static int filldir64(struct dir_context *ctx, const char *name, int namlen,
253 loff_t offset, u64 ino, unsigned int d_type)
254{
255 struct linux_dirent64 __user *dirent;
256 struct getdents_callback64 *buf =
257 container_of(ctx, struct getdents_callback64, ctx);
258 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
259 sizeof(u64));
260
261 buf->error = -EINVAL; /* only used if we fail.. */
262 if (reclen > buf->count)
263 return -EINVAL;
264 dirent = buf->previous;
265 if (dirent) {
266 if (signal_pending(current))
267 return -EINTR;
268 if (__put_user(offset, &dirent->d_off))
269 goto efault;
270 }
271 dirent = buf->current_dir;
272 if (__put_user(ino, &dirent->d_ino))
273 goto efault;
274 if (__put_user(0, &dirent->d_off))
275 goto efault;
276 if (__put_user(reclen, &dirent->d_reclen))
277 goto efault;
278 if (__put_user(d_type, &dirent->d_type))
279 goto efault;
280 if (copy_to_user(dirent->d_name, name, namlen))
281 goto efault;
282 if (__put_user(0, dirent->d_name + namlen))
283 goto efault;
284 buf->previous = dirent;
285 dirent = (void __user *)dirent + reclen;
286 buf->current_dir = dirent;
287 buf->count -= reclen;
288 return 0;
289efault:
290 buf->error = -EFAULT;
291 return -EFAULT;
292}
293
294SYSCALL_DEFINE3(getdents64, unsigned int, fd,
295 struct linux_dirent64 __user *, dirent, unsigned int, count)
296{
297 struct fd f;
298 struct linux_dirent64 __user * lastdirent;
299 struct getdents_callback64 buf = {
300 .ctx.actor = filldir64,
301 .count = count,
302 .current_dir = dirent
303 };
304 int error;
305
306 if (!access_ok(VERIFY_WRITE, dirent, count))
307 return -EFAULT;
308
309 f = fdget_pos(fd);
310 if (!f.file)
311 return -EBADF;
312
313 error = iterate_dir(f.file, &buf.ctx);
314 if (error >= 0)
315 error = buf.error;
316 lastdirent = buf.previous;
317 if (lastdirent) {
318 typeof(lastdirent->d_off) d_off = buf.ctx.pos;
319 if (__put_user(d_off, &lastdirent->d_off))
320 error = -EFAULT;
321 else
322 error = count - buf.count;
323 }
324 fdput_pos(f);
325 return error;
326}
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 * Note the "unsafe_put_user() semantics: we goto a
29 * label for errors.
30 */
31#define unsafe_copy_dirent_name(_dst, _src, _len, label) do { \
32 char __user *dst = (_dst); \
33 const char *src = (_src); \
34 size_t len = (_len); \
35 unsafe_put_user(0, dst+len, label); \
36 unsafe_copy_to_user(dst, src, len, label); \
37} while (0)
38
39
40int iterate_dir(struct file *file, struct dir_context *ctx)
41{
42 struct inode *inode = file_inode(file);
43 bool shared = false;
44 int res = -ENOTDIR;
45 if (file->f_op->iterate_shared)
46 shared = true;
47 else if (!file->f_op->iterate)
48 goto out;
49
50 res = security_file_permission(file, MAY_READ);
51 if (res)
52 goto out;
53
54 if (shared)
55 res = down_read_killable(&inode->i_rwsem);
56 else
57 res = down_write_killable(&inode->i_rwsem);
58 if (res)
59 goto out;
60
61 res = -ENOENT;
62 if (!IS_DEADDIR(inode)) {
63 ctx->pos = file->f_pos;
64 if (shared)
65 res = file->f_op->iterate_shared(file, ctx);
66 else
67 res = file->f_op->iterate(file, ctx);
68 file->f_pos = ctx->pos;
69 fsnotify_access(file);
70 file_accessed(file);
71 }
72 if (shared)
73 inode_unlock_shared(inode);
74 else
75 inode_unlock(inode);
76out:
77 return res;
78}
79EXPORT_SYMBOL(iterate_dir);
80
81/*
82 * POSIX says that a dirent name cannot contain NULL or a '/'.
83 *
84 * It's not 100% clear what we should really do in this case.
85 * The filesystem is clearly corrupted, but returning a hard
86 * error means that you now don't see any of the other names
87 * either, so that isn't a perfect alternative.
88 *
89 * And if you return an error, what error do you use? Several
90 * filesystems seem to have decided on EUCLEAN being the error
91 * code for EFSCORRUPTED, and that may be the error to use. Or
92 * just EIO, which is perhaps more obvious to users.
93 *
94 * In order to see the other file names in the directory, the
95 * caller might want to make this a "soft" error: skip the
96 * entry, and return the error at the end instead.
97 *
98 * Note that this should likely do a "memchr(name, 0, len)"
99 * check too, since that would be filesystem corruption as
100 * well. However, that case can't actually confuse user space,
101 * which has to do a strlen() on the name anyway to find the
102 * filename length, and the above "soft error" worry means
103 * that it's probably better left alone until we have that
104 * issue clarified.
105 */
106static int verify_dirent_name(const char *name, int len)
107{
108 if (!len)
109 return -EIO;
110 if (memchr(name, '/', len))
111 return -EIO;
112 return 0;
113}
114
115/*
116 * Traditional linux readdir() handling..
117 *
118 * "count=1" is a special case, meaning that the buffer is one
119 * dirent-structure in size and that the code can't handle more
120 * anyway. Thus the special "fillonedir()" function for that
121 * case (the low-level handlers don't need to care about this).
122 */
123
124#ifdef __ARCH_WANT_OLD_READDIR
125
126struct old_linux_dirent {
127 unsigned long d_ino;
128 unsigned long d_offset;
129 unsigned short d_namlen;
130 char d_name[1];
131};
132
133struct readdir_callback {
134 struct dir_context ctx;
135 struct old_linux_dirent __user * dirent;
136 int result;
137};
138
139static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
140 loff_t offset, u64 ino, unsigned int d_type)
141{
142 struct readdir_callback *buf =
143 container_of(ctx, struct readdir_callback, ctx);
144 struct old_linux_dirent __user * dirent;
145 unsigned long d_ino;
146
147 if (buf->result)
148 return -EINVAL;
149 d_ino = ino;
150 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
151 buf->result = -EOVERFLOW;
152 return -EOVERFLOW;
153 }
154 buf->result++;
155 dirent = buf->dirent;
156 if (!access_ok(dirent,
157 (unsigned long)(dirent->d_name + namlen + 1) -
158 (unsigned long)dirent))
159 goto efault;
160 if ( __put_user(d_ino, &dirent->d_ino) ||
161 __put_user(offset, &dirent->d_offset) ||
162 __put_user(namlen, &dirent->d_namlen) ||
163 __copy_to_user(dirent->d_name, name, namlen) ||
164 __put_user(0, dirent->d_name + namlen))
165 goto efault;
166 return 0;
167efault:
168 buf->result = -EFAULT;
169 return -EFAULT;
170}
171
172SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
173 struct old_linux_dirent __user *, dirent, unsigned int, count)
174{
175 int error;
176 struct fd f = fdget_pos(fd);
177 struct readdir_callback buf = {
178 .ctx.actor = fillonedir,
179 .dirent = dirent
180 };
181
182 if (!f.file)
183 return -EBADF;
184
185 error = iterate_dir(f.file, &buf.ctx);
186 if (buf.result)
187 error = buf.result;
188
189 fdput_pos(f);
190 return error;
191}
192
193#endif /* __ARCH_WANT_OLD_READDIR */
194
195/*
196 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
197 * interface.
198 */
199struct linux_dirent {
200 unsigned long d_ino;
201 unsigned long d_off;
202 unsigned short d_reclen;
203 char d_name[1];
204};
205
206struct getdents_callback {
207 struct dir_context ctx;
208 struct linux_dirent __user * current_dir;
209 struct linux_dirent __user * previous;
210 int count;
211 int error;
212};
213
214static int filldir(struct dir_context *ctx, const char *name, int namlen,
215 loff_t offset, u64 ino, unsigned int d_type)
216{
217 struct linux_dirent __user * dirent;
218 struct getdents_callback *buf =
219 container_of(ctx, struct getdents_callback, ctx);
220 unsigned long d_ino;
221 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
222 sizeof(long));
223
224 buf->error = verify_dirent_name(name, namlen);
225 if (unlikely(buf->error))
226 return buf->error;
227 buf->error = -EINVAL; /* only used if we fail.. */
228 if (reclen > buf->count)
229 return -EINVAL;
230 d_ino = ino;
231 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
232 buf->error = -EOVERFLOW;
233 return -EOVERFLOW;
234 }
235 dirent = buf->previous;
236 if (dirent && signal_pending(current))
237 return -EINTR;
238
239 /*
240 * Note! This range-checks 'previous' (which may be NULL).
241 * The real range was checked in getdents
242 */
243 if (!user_access_begin(dirent, sizeof(*dirent)))
244 goto efault;
245 if (dirent)
246 unsafe_put_user(offset, &dirent->d_off, efault_end);
247 dirent = buf->current_dir;
248 unsafe_put_user(d_ino, &dirent->d_ino, efault_end);
249 unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
250 unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end);
251 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
252 user_access_end();
253
254 buf->previous = dirent;
255 dirent = (void __user *)dirent + reclen;
256 buf->current_dir = dirent;
257 buf->count -= reclen;
258 return 0;
259efault_end:
260 user_access_end();
261efault:
262 buf->error = -EFAULT;
263 return -EFAULT;
264}
265
266SYSCALL_DEFINE3(getdents, unsigned int, fd,
267 struct linux_dirent __user *, dirent, unsigned int, count)
268{
269 struct fd f;
270 struct linux_dirent __user * lastdirent;
271 struct getdents_callback buf = {
272 .ctx.actor = filldir,
273 .count = count,
274 .current_dir = dirent
275 };
276 int error;
277
278 if (!access_ok(dirent, count))
279 return -EFAULT;
280
281 f = fdget_pos(fd);
282 if (!f.file)
283 return -EBADF;
284
285 error = iterate_dir(f.file, &buf.ctx);
286 if (error >= 0)
287 error = buf.error;
288 lastdirent = buf.previous;
289 if (lastdirent) {
290 if (put_user(buf.ctx.pos, &lastdirent->d_off))
291 error = -EFAULT;
292 else
293 error = count - buf.count;
294 }
295 fdput_pos(f);
296 return error;
297}
298
299struct getdents_callback64 {
300 struct dir_context ctx;
301 struct linux_dirent64 __user * current_dir;
302 struct linux_dirent64 __user * previous;
303 int count;
304 int error;
305};
306
307static int filldir64(struct dir_context *ctx, const char *name, int namlen,
308 loff_t offset, u64 ino, unsigned int d_type)
309{
310 struct linux_dirent64 __user *dirent;
311 struct getdents_callback64 *buf =
312 container_of(ctx, struct getdents_callback64, ctx);
313 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
314 sizeof(u64));
315
316 buf->error = verify_dirent_name(name, namlen);
317 if (unlikely(buf->error))
318 return buf->error;
319 buf->error = -EINVAL; /* only used if we fail.. */
320 if (reclen > buf->count)
321 return -EINVAL;
322 dirent = buf->previous;
323 if (dirent && signal_pending(current))
324 return -EINTR;
325
326 /*
327 * Note! This range-checks 'previous' (which may be NULL).
328 * The real range was checked in getdents
329 */
330 if (!user_access_begin(dirent, sizeof(*dirent)))
331 goto efault;
332 if (dirent)
333 unsafe_put_user(offset, &dirent->d_off, efault_end);
334 dirent = buf->current_dir;
335 unsafe_put_user(ino, &dirent->d_ino, efault_end);
336 unsafe_put_user(reclen, &dirent->d_reclen, efault_end);
337 unsafe_put_user(d_type, &dirent->d_type, efault_end);
338 unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end);
339 user_access_end();
340
341 buf->previous = dirent;
342 dirent = (void __user *)dirent + reclen;
343 buf->current_dir = dirent;
344 buf->count -= reclen;
345 return 0;
346efault_end:
347 user_access_end();
348efault:
349 buf->error = -EFAULT;
350 return -EFAULT;
351}
352
353int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
354 unsigned int count)
355{
356 struct fd f;
357 struct linux_dirent64 __user * lastdirent;
358 struct getdents_callback64 buf = {
359 .ctx.actor = filldir64,
360 .count = count,
361 .current_dir = dirent
362 };
363 int error;
364
365 if (!access_ok(dirent, count))
366 return -EFAULT;
367
368 f = fdget_pos(fd);
369 if (!f.file)
370 return -EBADF;
371
372 error = iterate_dir(f.file, &buf.ctx);
373 if (error >= 0)
374 error = buf.error;
375 lastdirent = buf.previous;
376 if (lastdirent) {
377 typeof(lastdirent->d_off) d_off = buf.ctx.pos;
378 if (__put_user(d_off, &lastdirent->d_off))
379 error = -EFAULT;
380 else
381 error = count - buf.count;
382 }
383 fdput_pos(f);
384 return error;
385}
386
387
388SYSCALL_DEFINE3(getdents64, unsigned int, fd,
389 struct linux_dirent64 __user *, dirent, unsigned int, count)
390{
391 return ksys_getdents64(fd, dirent, count);
392}
393
394#ifdef CONFIG_COMPAT
395struct compat_old_linux_dirent {
396 compat_ulong_t d_ino;
397 compat_ulong_t d_offset;
398 unsigned short d_namlen;
399 char d_name[1];
400};
401
402struct compat_readdir_callback {
403 struct dir_context ctx;
404 struct compat_old_linux_dirent __user *dirent;
405 int result;
406};
407
408static int compat_fillonedir(struct dir_context *ctx, const char *name,
409 int namlen, loff_t offset, u64 ino,
410 unsigned int d_type)
411{
412 struct compat_readdir_callback *buf =
413 container_of(ctx, struct compat_readdir_callback, ctx);
414 struct compat_old_linux_dirent __user *dirent;
415 compat_ulong_t d_ino;
416
417 if (buf->result)
418 return -EINVAL;
419 d_ino = ino;
420 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
421 buf->result = -EOVERFLOW;
422 return -EOVERFLOW;
423 }
424 buf->result++;
425 dirent = buf->dirent;
426 if (!access_ok(dirent,
427 (unsigned long)(dirent->d_name + namlen + 1) -
428 (unsigned long)dirent))
429 goto efault;
430 if ( __put_user(d_ino, &dirent->d_ino) ||
431 __put_user(offset, &dirent->d_offset) ||
432 __put_user(namlen, &dirent->d_namlen) ||
433 __copy_to_user(dirent->d_name, name, namlen) ||
434 __put_user(0, dirent->d_name + namlen))
435 goto efault;
436 return 0;
437efault:
438 buf->result = -EFAULT;
439 return -EFAULT;
440}
441
442COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
443 struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
444{
445 int error;
446 struct fd f = fdget_pos(fd);
447 struct compat_readdir_callback buf = {
448 .ctx.actor = compat_fillonedir,
449 .dirent = dirent
450 };
451
452 if (!f.file)
453 return -EBADF;
454
455 error = iterate_dir(f.file, &buf.ctx);
456 if (buf.result)
457 error = buf.result;
458
459 fdput_pos(f);
460 return error;
461}
462
463struct compat_linux_dirent {
464 compat_ulong_t d_ino;
465 compat_ulong_t d_off;
466 unsigned short d_reclen;
467 char d_name[1];
468};
469
470struct compat_getdents_callback {
471 struct dir_context ctx;
472 struct compat_linux_dirent __user *current_dir;
473 struct compat_linux_dirent __user *previous;
474 int count;
475 int error;
476};
477
478static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
479 loff_t offset, u64 ino, unsigned int d_type)
480{
481 struct compat_linux_dirent __user * dirent;
482 struct compat_getdents_callback *buf =
483 container_of(ctx, struct compat_getdents_callback, ctx);
484 compat_ulong_t d_ino;
485 int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
486 namlen + 2, sizeof(compat_long_t));
487
488 buf->error = -EINVAL; /* only used if we fail.. */
489 if (reclen > buf->count)
490 return -EINVAL;
491 d_ino = ino;
492 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
493 buf->error = -EOVERFLOW;
494 return -EOVERFLOW;
495 }
496 dirent = buf->previous;
497 if (dirent) {
498 if (signal_pending(current))
499 return -EINTR;
500 if (__put_user(offset, &dirent->d_off))
501 goto efault;
502 }
503 dirent = buf->current_dir;
504 if (__put_user(d_ino, &dirent->d_ino))
505 goto efault;
506 if (__put_user(reclen, &dirent->d_reclen))
507 goto efault;
508 if (copy_to_user(dirent->d_name, name, namlen))
509 goto efault;
510 if (__put_user(0, dirent->d_name + namlen))
511 goto efault;
512 if (__put_user(d_type, (char __user *) dirent + reclen - 1))
513 goto efault;
514 buf->previous = dirent;
515 dirent = (void __user *)dirent + reclen;
516 buf->current_dir = dirent;
517 buf->count -= reclen;
518 return 0;
519efault:
520 buf->error = -EFAULT;
521 return -EFAULT;
522}
523
524COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
525 struct compat_linux_dirent __user *, dirent, unsigned int, count)
526{
527 struct fd f;
528 struct compat_linux_dirent __user * lastdirent;
529 struct compat_getdents_callback buf = {
530 .ctx.actor = compat_filldir,
531 .current_dir = dirent,
532 .count = count
533 };
534 int error;
535
536 if (!access_ok(dirent, count))
537 return -EFAULT;
538
539 f = fdget_pos(fd);
540 if (!f.file)
541 return -EBADF;
542
543 error = iterate_dir(f.file, &buf.ctx);
544 if (error >= 0)
545 error = buf.error;
546 lastdirent = buf.previous;
547 if (lastdirent) {
548 if (put_user(buf.ctx.pos, &lastdirent->d_off))
549 error = -EFAULT;
550 else
551 error = count - buf.count;
552 }
553 fdput_pos(f);
554 return error;
555}
556#endif