blob: 1b83b0ad183b656b06597dc65ab7d42883cc116e [file] [log] [blame]
Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * linux/fs/readdir.c
4 *
5 * Copyright (C) 1995 Linus Torvalds
6 */
7
Kevin Winchester85c9fe82010-08-09 17:20:22 -07008#include <linux/stddef.h>
Milind Arun Choudhary022a1692007-05-08 00:29:02 -07009#include <linux/kernel.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -050010#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/time.h>
12#include <linux/mm.h>
13#include <linux/errno.h>
14#include <linux/stat.h>
15#include <linux/file.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/fs.h>
Heinrich Schuchardtd4c7cf62014-06-04 16:05:41 -070017#include <linux/fsnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/dirent.h>
19#include <linux/security.h>
20#include <linux/syscalls.h>
21#include <linux/unistd.h>
Al Viro0460b2a2017-04-08 18:10:08 -040022#include <linux/compat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080024#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
Al Viro5c0ba4e2013-05-15 13:52:59 -040026int iterate_dir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -070027{
Al Viro496ad9a2013-01-23 17:07:38 -050028 struct inode *inode = file_inode(file);
Al Viro61922692016-04-20 23:08:32 -040029 bool shared = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 int res = -ENOTDIR;
Al Viro61922692016-04-20 23:08:32 -040031 if (file->f_op->iterate_shared)
32 shared = true;
33 else if (!file->f_op->iterate)
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 goto out;
35
36 res = security_file_permission(file, MAY_READ);
37 if (res)
38 goto out;
39
Kirill Tkhai0dc208b2017-09-29 19:06:48 +030040 if (shared)
41 res = down_read_killable(&inode->i_rwsem);
42 else
Al Viro00235412016-05-26 00:05:12 -040043 res = down_write_killable(&inode->i_rwsem);
Kirill Tkhai0dc208b2017-09-29 19:06:48 +030044 if (res)
45 goto out;
Liam R. Howlettda784512007-12-06 17:39:54 -050046
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 res = -ENOENT;
48 if (!IS_DEADDIR(inode)) {
Al Viro2233f312013-05-22 21:44:23 -040049 ctx->pos = file->f_pos;
Al Viro61922692016-04-20 23:08:32 -040050 if (shared)
51 res = file->f_op->iterate_shared(file, ctx);
52 else
53 res = file->f_op->iterate(file, ctx);
Al Viro2233f312013-05-22 21:44:23 -040054 file->f_pos = ctx->pos;
Heinrich Schuchardtd4c7cf62014-06-04 16:05:41 -070055 fsnotify_access(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 file_accessed(file);
57 }
Al Viro61922692016-04-20 23:08:32 -040058 if (shared)
59 inode_unlock_shared(inode);
60 else
61 inode_unlock(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062out:
63 return res;
64}
Al Viro5c0ba4e2013-05-15 13:52:59 -040065EXPORT_SYMBOL(iterate_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67/*
68 * Traditional linux readdir() handling..
69 *
70 * "count=1" is a special case, meaning that the buffer is one
71 * dirent-structure in size and that the code can't handle more
72 * anyway. Thus the special "fillonedir()" function for that
73 * case (the low-level handlers don't need to care about this).
74 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
76#ifdef __ARCH_WANT_OLD_READDIR
77
78struct old_linux_dirent {
79 unsigned long d_ino;
80 unsigned long d_offset;
81 unsigned short d_namlen;
82 char d_name[1];
83};
84
85struct readdir_callback {
Al Viro5c0ba4e2013-05-15 13:52:59 -040086 struct dir_context ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 struct old_linux_dirent __user * dirent;
88 int result;
89};
90
Miklos Szerediac7576f2014-10-30 17:37:34 +010091static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
92 loff_t offset, u64 ino, unsigned int d_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -070093{
Miklos Szerediac7576f2014-10-30 17:37:34 +010094 struct readdir_callback *buf =
95 container_of(ctx, struct readdir_callback, ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 struct old_linux_dirent __user * dirent;
David Howellsafefdbb2006-10-03 01:13:46 -070097 unsigned long d_ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
99 if (buf->result)
100 return -EINVAL;
David Howellsafefdbb2006-10-03 01:13:46 -0700101 d_ino = ino;
Al Viro8f3f6552008-08-12 00:28:24 -0400102 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
103 buf->result = -EOVERFLOW;
David Howellsafefdbb2006-10-03 01:13:46 -0700104 return -EOVERFLOW;
Al Viro8f3f6552008-08-12 00:28:24 -0400105 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 buf->result++;
107 dirent = buf->dirent;
108 if (!access_ok(VERIFY_WRITE, dirent,
109 (unsigned long)(dirent->d_name + namlen + 1) -
110 (unsigned long)dirent))
111 goto efault;
David Howellsafefdbb2006-10-03 01:13:46 -0700112 if ( __put_user(d_ino, &dirent->d_ino) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 __put_user(offset, &dirent->d_offset) ||
114 __put_user(namlen, &dirent->d_namlen) ||
115 __copy_to_user(dirent->d_name, name, namlen) ||
116 __put_user(0, dirent->d_name + namlen))
117 goto efault;
118 return 0;
119efault:
120 buf->result = -EFAULT;
121 return -EFAULT;
122}
123
Heiko Carstensd4e82042009-01-14 14:14:34 +0100124SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
125 struct old_linux_dirent __user *, dirent, unsigned int, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126{
127 int error;
Al Viro63b6df12016-04-20 17:08:21 -0400128 struct fd f = fdget_pos(fd);
Al Viroac6614b2013-05-22 22:22:04 -0400129 struct readdir_callback buf = {
130 .ctx.actor = fillonedir,
131 .dirent = dirent
132 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
Al Viro2903ff02012-08-28 12:52:22 -0400134 if (!f.file)
Al Viro863ced72012-04-21 18:40:32 -0400135 return -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
Al Viro5c0ba4e2013-05-15 13:52:59 -0400137 error = iterate_dir(f.file, &buf.ctx);
Al Viro53c9c5c2008-08-24 07:29:52 -0400138 if (buf.result)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 error = buf.result;
140
Al Viro63b6df12016-04-20 17:08:21 -0400141 fdput_pos(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 return error;
143}
144
145#endif /* __ARCH_WANT_OLD_READDIR */
146
147/*
148 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
149 * interface.
150 */
151struct linux_dirent {
152 unsigned long d_ino;
153 unsigned long d_off;
154 unsigned short d_reclen;
155 char d_name[1];
156};
157
158struct getdents_callback {
Al Viro5c0ba4e2013-05-15 13:52:59 -0400159 struct dir_context ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 struct linux_dirent __user * current_dir;
161 struct linux_dirent __user * previous;
162 int count;
163 int error;
164};
165
Miklos Szerediac7576f2014-10-30 17:37:34 +0100166static int filldir(struct dir_context *ctx, const char *name, int namlen,
167 loff_t offset, u64 ino, unsigned int d_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168{
169 struct linux_dirent __user * dirent;
Miklos Szerediac7576f2014-10-30 17:37:34 +0100170 struct getdents_callback *buf =
171 container_of(ctx, struct getdents_callback, ctx);
David Howellsafefdbb2006-10-03 01:13:46 -0700172 unsigned long d_ino;
Kevin Winchester85c9fe82010-08-09 17:20:22 -0700173 int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
174 sizeof(long));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
176 buf->error = -EINVAL; /* only used if we fail.. */
177 if (reclen > buf->count)
178 return -EINVAL;
David Howellsafefdbb2006-10-03 01:13:46 -0700179 d_ino = ino;
Al Viro8f3f6552008-08-12 00:28:24 -0400180 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
181 buf->error = -EOVERFLOW;
David Howellsafefdbb2006-10-03 01:13:46 -0700182 return -EOVERFLOW;
Al Viro8f3f6552008-08-12 00:28:24 -0400183 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 dirent = buf->previous;
185 if (dirent) {
Theodore Ts'o1f60fbe2016-04-23 22:50:07 -0400186 if (signal_pending(current))
187 return -EINTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 if (__put_user(offset, &dirent->d_off))
189 goto efault;
190 }
191 dirent = buf->current_dir;
David Howellsafefdbb2006-10-03 01:13:46 -0700192 if (__put_user(d_ino, &dirent->d_ino))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 goto efault;
194 if (__put_user(reclen, &dirent->d_reclen))
195 goto efault;
196 if (copy_to_user(dirent->d_name, name, namlen))
197 goto efault;
198 if (__put_user(0, dirent->d_name + namlen))
199 goto efault;
200 if (__put_user(d_type, (char __user *) dirent + reclen - 1))
201 goto efault;
202 buf->previous = dirent;
203 dirent = (void __user *)dirent + reclen;
204 buf->current_dir = dirent;
205 buf->count -= reclen;
206 return 0;
207efault:
208 buf->error = -EFAULT;
209 return -EFAULT;
210}
211
Heiko Carstens20f37032009-01-14 14:14:23 +0100212SYSCALL_DEFINE3(getdents, unsigned int, fd,
213 struct linux_dirent __user *, dirent, unsigned int, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214{
Al Viro2903ff02012-08-28 12:52:22 -0400215 struct fd f;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 struct linux_dirent __user * lastdirent;
Al Viroac6614b2013-05-22 22:22:04 -0400217 struct getdents_callback buf = {
218 .ctx.actor = filldir,
219 .count = count,
220 .current_dir = dirent
221 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 int error;
223
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 if (!access_ok(VERIFY_WRITE, dirent, count))
Al Viro863ced72012-04-21 18:40:32 -0400225 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
Al Viro63b6df12016-04-20 17:08:21 -0400227 f = fdget_pos(fd);
Al Viro2903ff02012-08-28 12:52:22 -0400228 if (!f.file)
Al Viro863ced72012-04-21 18:40:32 -0400229 return -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
Al Viro5c0ba4e2013-05-15 13:52:59 -0400231 error = iterate_dir(f.file, &buf.ctx);
Al Viro53c9c5c2008-08-24 07:29:52 -0400232 if (error >= 0)
233 error = buf.error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 lastdirent = buf.previous;
235 if (lastdirent) {
Al Virobb6f6192013-05-15 18:49:12 -0400236 if (put_user(buf.ctx.pos, &lastdirent->d_off))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 error = -EFAULT;
238 else
239 error = count - buf.count;
240 }
Al Viro63b6df12016-04-20 17:08:21 -0400241 fdput_pos(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 return error;
243}
244
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245struct getdents_callback64 {
Al Viro5c0ba4e2013-05-15 13:52:59 -0400246 struct dir_context ctx;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 struct linux_dirent64 __user * current_dir;
248 struct linux_dirent64 __user * previous;
249 int count;
250 int error;
251};
252
Miklos Szerediac7576f2014-10-30 17:37:34 +0100253static int filldir64(struct dir_context *ctx, const char *name, int namlen,
254 loff_t offset, u64 ino, unsigned int d_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255{
256 struct linux_dirent64 __user *dirent;
Miklos Szerediac7576f2014-10-30 17:37:34 +0100257 struct getdents_callback64 *buf =
258 container_of(ctx, struct getdents_callback64, ctx);
Kevin Winchester85c9fe82010-08-09 17:20:22 -0700259 int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
260 sizeof(u64));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
262 buf->error = -EINVAL; /* only used if we fail.. */
263 if (reclen > buf->count)
264 return -EINVAL;
265 dirent = buf->previous;
266 if (dirent) {
Theodore Ts'o1f60fbe2016-04-23 22:50:07 -0400267 if (signal_pending(current))
268 return -EINTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 if (__put_user(offset, &dirent->d_off))
270 goto efault;
271 }
272 dirent = buf->current_dir;
273 if (__put_user(ino, &dirent->d_ino))
274 goto efault;
275 if (__put_user(0, &dirent->d_off))
276 goto efault;
277 if (__put_user(reclen, &dirent->d_reclen))
278 goto efault;
279 if (__put_user(d_type, &dirent->d_type))
280 goto efault;
281 if (copy_to_user(dirent->d_name, name, namlen))
282 goto efault;
283 if (__put_user(0, dirent->d_name + namlen))
284 goto efault;
285 buf->previous = dirent;
286 dirent = (void __user *)dirent + reclen;
287 buf->current_dir = dirent;
288 buf->count -= reclen;
289 return 0;
290efault:
291 buf->error = -EFAULT;
292 return -EFAULT;
293}
294
Heiko Carstens20f37032009-01-14 14:14:23 +0100295SYSCALL_DEFINE3(getdents64, unsigned int, fd,
296 struct linux_dirent64 __user *, dirent, unsigned int, count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297{
Al Viro2903ff02012-08-28 12:52:22 -0400298 struct fd f;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 struct linux_dirent64 __user * lastdirent;
Al Viroac6614b2013-05-22 22:22:04 -0400300 struct getdents_callback64 buf = {
301 .ctx.actor = filldir64,
302 .count = count,
303 .current_dir = dirent
304 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 int error;
306
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 if (!access_ok(VERIFY_WRITE, dirent, count))
Al Viro863ced72012-04-21 18:40:32 -0400308 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309
Al Viro63b6df12016-04-20 17:08:21 -0400310 f = fdget_pos(fd);
Al Viro2903ff02012-08-28 12:52:22 -0400311 if (!f.file)
Al Viro863ced72012-04-21 18:40:32 -0400312 return -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
Al Viro5c0ba4e2013-05-15 13:52:59 -0400314 error = iterate_dir(f.file, &buf.ctx);
Al Viro53c9c5c2008-08-24 07:29:52 -0400315 if (error >= 0)
316 error = buf.error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 lastdirent = buf.previous;
318 if (lastdirent) {
Al Virobb6f6192013-05-15 18:49:12 -0400319 typeof(lastdirent->d_off) d_off = buf.ctx.pos;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 if (__put_user(d_off, &lastdirent->d_off))
Al Viro53c9c5c2008-08-24 07:29:52 -0400321 error = -EFAULT;
322 else
323 error = count - buf.count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 }
Al Viro63b6df12016-04-20 17:08:21 -0400325 fdput_pos(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 return error;
327}
Al Viro0460b2a2017-04-08 18:10:08 -0400328
329#ifdef CONFIG_COMPAT
330struct compat_old_linux_dirent {
331 compat_ulong_t d_ino;
332 compat_ulong_t d_offset;
333 unsigned short d_namlen;
334 char d_name[1];
335};
336
337struct compat_readdir_callback {
338 struct dir_context ctx;
339 struct compat_old_linux_dirent __user *dirent;
340 int result;
341};
342
343static int compat_fillonedir(struct dir_context *ctx, const char *name,
344 int namlen, loff_t offset, u64 ino,
345 unsigned int d_type)
346{
347 struct compat_readdir_callback *buf =
348 container_of(ctx, struct compat_readdir_callback, ctx);
349 struct compat_old_linux_dirent __user *dirent;
350 compat_ulong_t d_ino;
351
352 if (buf->result)
353 return -EINVAL;
354 d_ino = ino;
355 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
356 buf->result = -EOVERFLOW;
357 return -EOVERFLOW;
358 }
359 buf->result++;
360 dirent = buf->dirent;
361 if (!access_ok(VERIFY_WRITE, dirent,
362 (unsigned long)(dirent->d_name + namlen + 1) -
363 (unsigned long)dirent))
364 goto efault;
365 if ( __put_user(d_ino, &dirent->d_ino) ||
366 __put_user(offset, &dirent->d_offset) ||
367 __put_user(namlen, &dirent->d_namlen) ||
368 __copy_to_user(dirent->d_name, name, namlen) ||
369 __put_user(0, dirent->d_name + namlen))
370 goto efault;
371 return 0;
372efault:
373 buf->result = -EFAULT;
374 return -EFAULT;
375}
376
377COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
378 struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
379{
380 int error;
381 struct fd f = fdget_pos(fd);
382 struct compat_readdir_callback buf = {
383 .ctx.actor = compat_fillonedir,
384 .dirent = dirent
385 };
386
387 if (!f.file)
388 return -EBADF;
389
390 error = iterate_dir(f.file, &buf.ctx);
391 if (buf.result)
392 error = buf.result;
393
394 fdput_pos(f);
395 return error;
396}
397
398struct compat_linux_dirent {
399 compat_ulong_t d_ino;
400 compat_ulong_t d_off;
401 unsigned short d_reclen;
402 char d_name[1];
403};
404
405struct compat_getdents_callback {
406 struct dir_context ctx;
407 struct compat_linux_dirent __user *current_dir;
408 struct compat_linux_dirent __user *previous;
409 int count;
410 int error;
411};
412
413static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
414 loff_t offset, u64 ino, unsigned int d_type)
415{
416 struct compat_linux_dirent __user * dirent;
417 struct compat_getdents_callback *buf =
418 container_of(ctx, struct compat_getdents_callback, ctx);
419 compat_ulong_t d_ino;
420 int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
421 namlen + 2, sizeof(compat_long_t));
422
423 buf->error = -EINVAL; /* only used if we fail.. */
424 if (reclen > buf->count)
425 return -EINVAL;
426 d_ino = ino;
427 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
428 buf->error = -EOVERFLOW;
429 return -EOVERFLOW;
430 }
431 dirent = buf->previous;
432 if (dirent) {
433 if (signal_pending(current))
434 return -EINTR;
435 if (__put_user(offset, &dirent->d_off))
436 goto efault;
437 }
438 dirent = buf->current_dir;
439 if (__put_user(d_ino, &dirent->d_ino))
440 goto efault;
441 if (__put_user(reclen, &dirent->d_reclen))
442 goto efault;
443 if (copy_to_user(dirent->d_name, name, namlen))
444 goto efault;
445 if (__put_user(0, dirent->d_name + namlen))
446 goto efault;
447 if (__put_user(d_type, (char __user *) dirent + reclen - 1))
448 goto efault;
449 buf->previous = dirent;
450 dirent = (void __user *)dirent + reclen;
451 buf->current_dir = dirent;
452 buf->count -= reclen;
453 return 0;
454efault:
455 buf->error = -EFAULT;
456 return -EFAULT;
457}
458
459COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
460 struct compat_linux_dirent __user *, dirent, unsigned int, count)
461{
462 struct fd f;
463 struct compat_linux_dirent __user * lastdirent;
464 struct compat_getdents_callback buf = {
465 .ctx.actor = compat_filldir,
466 .current_dir = dirent,
467 .count = count
468 };
469 int error;
470
471 if (!access_ok(VERIFY_WRITE, dirent, count))
472 return -EFAULT;
473
474 f = fdget_pos(fd);
475 if (!f.file)
476 return -EBADF;
477
478 error = iterate_dir(f.file, &buf.ctx);
479 if (error >= 0)
480 error = buf.error;
481 lastdirent = buf.previous;
482 if (lastdirent) {
483 if (put_user(buf.ctx.pos, &lastdirent->d_off))
484 error = -EFAULT;
485 else
486 error = count - buf.count;
487 }
488 fdput_pos(f);
489 return error;
490}
491#endif