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Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/fs/open.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | */ | |
7 | ||
8 | #include <linux/string.h> | |
9 | #include <linux/mm.h> | |
1da177e4 | 10 | #include <linux/file.h> |
9f3acc31 | 11 | #include <linux/fdtable.h> |
0eeca283 | 12 | #include <linux/fsnotify.h> |
1da177e4 | 13 | #include <linux/module.h> |
1da177e4 LT |
14 | #include <linux/tty.h> |
15 | #include <linux/namei.h> | |
16 | #include <linux/backing-dev.h> | |
16f7e0fe | 17 | #include <linux/capability.h> |
086f7316 | 18 | #include <linux/securebits.h> |
1da177e4 LT |
19 | #include <linux/security.h> |
20 | #include <linux/mount.h> | |
5590ff0d | 21 | #include <linux/fcntl.h> |
5a0e3ad6 | 22 | #include <linux/slab.h> |
7c0f6ba6 | 23 | #include <linux/uaccess.h> |
1da177e4 | 24 | #include <linux/fs.h> |
ef3daeda | 25 | #include <linux/personality.h> |
1da177e4 LT |
26 | #include <linux/pagemap.h> |
27 | #include <linux/syscalls.h> | |
ab2af1f5 | 28 | #include <linux/rcupdate.h> |
73241ccc | 29 | #include <linux/audit.h> |
97ac7350 | 30 | #include <linux/falloc.h> |
5ad4e53b | 31 | #include <linux/fs_struct.h> |
b65a9cfc | 32 | #include <linux/ima.h> |
2dfc1cae | 33 | #include <linux/dnotify.h> |
3f6d078d | 34 | #include <linux/compat.h> |
1da177e4 | 35 | |
e81e3f4d EP |
36 | #include "internal.h" |
37 | ||
4a30131e N |
38 | int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs, |
39 | struct file *filp) | |
1da177e4 | 40 | { |
939a9421 | 41 | int ret; |
1da177e4 LT |
42 | struct iattr newattrs; |
43 | ||
44 | /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ | |
45 | if (length < 0) | |
46 | return -EINVAL; | |
47 | ||
48 | newattrs.ia_size = length; | |
4a30131e | 49 | newattrs.ia_valid = ATTR_SIZE | time_attrs; |
cc4e69de MS |
50 | if (filp) { |
51 | newattrs.ia_file = filp; | |
52 | newattrs.ia_valid |= ATTR_FILE; | |
53 | } | |
1da177e4 | 54 | |
45f147a1 JK |
55 | /* Remove suid, sgid, and file capabilities on truncate too */ |
56 | ret = dentry_needs_remove_privs(dentry); | |
57 | if (ret < 0) | |
58 | return ret; | |
939a9421 AW |
59 | if (ret) |
60 | newattrs.ia_valid |= ret | ATTR_FORCE; | |
7b82dc0e | 61 | |
5955102c | 62 | inode_lock(dentry->d_inode); |
27ac0ffe BF |
63 | /* Note any delegations or leases have already been broken: */ |
64 | ret = notify_change(dentry, &newattrs, NULL); | |
5955102c | 65 | inode_unlock(dentry->d_inode); |
939a9421 | 66 | return ret; |
1da177e4 LT |
67 | } |
68 | ||
7df818b2 | 69 | long vfs_truncate(const struct path *path, loff_t length) |
1da177e4 | 70 | { |
2d8f3038 | 71 | struct inode *inode; |
a02de960 | 72 | long error; |
1da177e4 | 73 | |
a02de960 | 74 | inode = path->dentry->d_inode; |
1da177e4 LT |
75 | |
76 | /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ | |
1da177e4 | 77 | if (S_ISDIR(inode->i_mode)) |
a02de960 | 78 | return -EISDIR; |
1da177e4 | 79 | if (!S_ISREG(inode->i_mode)) |
a02de960 | 80 | return -EINVAL; |
1da177e4 | 81 | |
a02de960 | 82 | error = mnt_want_write(path->mnt); |
1da177e4 | 83 | if (error) |
a02de960 | 84 | goto out; |
1da177e4 | 85 | |
256984a8 | 86 | error = inode_permission(inode, MAY_WRITE); |
9ac9b847 DH |
87 | if (error) |
88 | goto mnt_drop_write_and_out; | |
1da177e4 LT |
89 | |
90 | error = -EPERM; | |
c82e42da | 91 | if (IS_APPEND(inode)) |
9ac9b847 | 92 | goto mnt_drop_write_and_out; |
1da177e4 | 93 | |
8cf9ee50 | 94 | error = get_write_access(inode); |
1da177e4 | 95 | if (error) |
9ac9b847 | 96 | goto mnt_drop_write_and_out; |
1da177e4 | 97 | |
9700382c | 98 | /* |
99 | * Make sure that there are no leases. get_write_access() protects | |
100 | * against the truncate racing with a lease-granting setlease(). | |
101 | */ | |
8737c930 | 102 | error = break_lease(inode, O_WRONLY); |
1da177e4 | 103 | if (error) |
9700382c | 104 | goto put_write_and_out; |
1da177e4 LT |
105 | |
106 | error = locks_verify_truncate(inode, NULL, length); | |
be6d3e56 | 107 | if (!error) |
a02de960 | 108 | error = security_path_truncate(path); |
907f4554 | 109 | if (!error) |
a02de960 | 110 | error = do_truncate(path->dentry, length, 0, NULL); |
1da177e4 | 111 | |
9700382c | 112 | put_write_and_out: |
8cf9ee50 | 113 | put_write_access(inode); |
9ac9b847 | 114 | mnt_drop_write_and_out: |
a02de960 | 115 | mnt_drop_write(path->mnt); |
1da177e4 LT |
116 | out: |
117 | return error; | |
118 | } | |
a02de960 DH |
119 | EXPORT_SYMBOL_GPL(vfs_truncate); |
120 | ||
df260e21 | 121 | long do_sys_truncate(const char __user *pathname, loff_t length) |
a02de960 | 122 | { |
48f7530d | 123 | unsigned int lookup_flags = LOOKUP_FOLLOW; |
a02de960 DH |
124 | struct path path; |
125 | int error; | |
126 | ||
127 | if (length < 0) /* sorry, but loff_t says... */ | |
128 | return -EINVAL; | |
129 | ||
48f7530d JL |
130 | retry: |
131 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
a02de960 DH |
132 | if (!error) { |
133 | error = vfs_truncate(&path, length); | |
134 | path_put(&path); | |
135 | } | |
48f7530d JL |
136 | if (retry_estale(error, lookup_flags)) { |
137 | lookup_flags |= LOOKUP_REVAL; | |
138 | goto retry; | |
139 | } | |
a02de960 DH |
140 | return error; |
141 | } | |
1da177e4 | 142 | |
4fd8da8d | 143 | SYSCALL_DEFINE2(truncate, const char __user *, path, long, length) |
1da177e4 | 144 | { |
4fd8da8d | 145 | return do_sys_truncate(path, length); |
1da177e4 LT |
146 | } |
147 | ||
3f6d078d AV |
148 | #ifdef CONFIG_COMPAT |
149 | COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length) | |
150 | { | |
151 | return do_sys_truncate(path, length); | |
152 | } | |
153 | #endif | |
154 | ||
411d9475 | 155 | long do_sys_ftruncate(unsigned int fd, loff_t length, int small) |
1da177e4 | 156 | { |
bf2965d5 | 157 | struct inode *inode; |
1da177e4 | 158 | struct dentry *dentry; |
2903ff01 | 159 | struct fd f; |
1da177e4 LT |
160 | int error; |
161 | ||
162 | error = -EINVAL; | |
163 | if (length < 0) | |
164 | goto out; | |
165 | error = -EBADF; | |
2903ff01 AV |
166 | f = fdget(fd); |
167 | if (!f.file) | |
1da177e4 LT |
168 | goto out; |
169 | ||
170 | /* explicitly opened as large or we are on 64-bit box */ | |
2903ff01 | 171 | if (f.file->f_flags & O_LARGEFILE) |
1da177e4 LT |
172 | small = 0; |
173 | ||
2903ff01 | 174 | dentry = f.file->f_path.dentry; |
1da177e4 LT |
175 | inode = dentry->d_inode; |
176 | error = -EINVAL; | |
2903ff01 | 177 | if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE)) |
1da177e4 LT |
178 | goto out_putf; |
179 | ||
180 | error = -EINVAL; | |
181 | /* Cannot ftruncate over 2^31 bytes without large file support */ | |
182 | if (small && length > MAX_NON_LFS) | |
183 | goto out_putf; | |
184 | ||
185 | error = -EPERM; | |
78757af6 AG |
186 | /* Check IS_APPEND on real upper inode */ |
187 | if (IS_APPEND(file_inode(f.file))) | |
1da177e4 LT |
188 | goto out_putf; |
189 | ||
14da9200 | 190 | sb_start_write(inode->i_sb); |
2903ff01 | 191 | error = locks_verify_truncate(inode, f.file, length); |
be6d3e56 | 192 | if (!error) |
2903ff01 | 193 | error = security_path_truncate(&f.file->f_path); |
1da177e4 | 194 | if (!error) |
2903ff01 | 195 | error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file); |
14da9200 | 196 | sb_end_write(inode->i_sb); |
1da177e4 | 197 | out_putf: |
2903ff01 | 198 | fdput(f); |
1da177e4 LT |
199 | out: |
200 | return error; | |
201 | } | |
202 | ||
bdc480e3 | 203 | SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length) |
1da177e4 | 204 | { |
2cf09666 | 205 | return do_sys_ftruncate(fd, length, 1); |
1da177e4 LT |
206 | } |
207 | ||
3f6d078d AV |
208 | #ifdef CONFIG_COMPAT |
209 | COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length) | |
210 | { | |
211 | return do_sys_ftruncate(fd, length, 1); | |
212 | } | |
213 | #endif | |
214 | ||
1da177e4 LT |
215 | /* LFS versions of truncate are only needed on 32 bit machines */ |
216 | #if BITS_PER_LONG == 32 | |
4a0fd5bf | 217 | SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length) |
1da177e4 LT |
218 | { |
219 | return do_sys_truncate(path, length); | |
220 | } | |
221 | ||
4a0fd5bf | 222 | SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length) |
1da177e4 | 223 | { |
2cf09666 | 224 | return do_sys_ftruncate(fd, length, 0); |
1da177e4 | 225 | } |
6673e0c3 | 226 | #endif /* BITS_PER_LONG == 32 */ |
1da177e4 | 227 | |
3e63cbb1 | 228 | |
72c72bdf | 229 | int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) |
97ac7350 | 230 | { |
496ad9aa | 231 | struct inode *inode = file_inode(file); |
3e63cbb1 | 232 | long ret; |
97ac7350 AA |
233 | |
234 | if (offset < 0 || len <= 0) | |
3e63cbb1 | 235 | return -EINVAL; |
97ac7350 AA |
236 | |
237 | /* Return error if mode is not supported */ | |
dd46c787 | 238 | if (mode & ~FALLOC_FL_SUPPORTED_MASK) |
409332b6 LC |
239 | return -EOPNOTSUPP; |
240 | ||
241 | /* Punch hole and zero range are mutually exclusive */ | |
242 | if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) == | |
243 | (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) | |
79124f18 JB |
244 | return -EOPNOTSUPP; |
245 | ||
246 | /* Punch hole must have keep size set */ | |
247 | if ((mode & FALLOC_FL_PUNCH_HOLE) && | |
248 | !(mode & FALLOC_FL_KEEP_SIZE)) | |
3e63cbb1 | 249 | return -EOPNOTSUPP; |
97ac7350 | 250 | |
00f5e619 NJ |
251 | /* Collapse range should only be used exclusively. */ |
252 | if ((mode & FALLOC_FL_COLLAPSE_RANGE) && | |
253 | (mode & ~FALLOC_FL_COLLAPSE_RANGE)) | |
254 | return -EINVAL; | |
255 | ||
dd46c787 NJ |
256 | /* Insert range should only be used exclusively. */ |
257 | if ((mode & FALLOC_FL_INSERT_RANGE) && | |
258 | (mode & ~FALLOC_FL_INSERT_RANGE)) | |
259 | return -EINVAL; | |
260 | ||
71be6b49 DW |
261 | /* Unshare range should only be used with allocate mode. */ |
262 | if ((mode & FALLOC_FL_UNSHARE_RANGE) && | |
263 | (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE))) | |
264 | return -EINVAL; | |
265 | ||
97ac7350 | 266 | if (!(file->f_mode & FMODE_WRITE)) |
3e63cbb1 | 267 | return -EBADF; |
1ca551c6 | 268 | |
00f5e619 | 269 | /* |
8fc61d92 | 270 | * We can only allow pure fallocate on append only files |
00f5e619 | 271 | */ |
8fc61d92 | 272 | if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode)) |
1ca551c6 MS |
273 | return -EPERM; |
274 | ||
275 | if (IS_IMMUTABLE(inode)) | |
276 | return -EPERM; | |
277 | ||
0790b31b | 278 | /* |
6d2b6170 | 279 | * We cannot allow any fallocate operation on an active swapfile |
0790b31b LC |
280 | */ |
281 | if (IS_SWAPFILE(inode)) | |
6d2b6170 | 282 | return -ETXTBSY; |
0790b31b | 283 | |
97ac7350 AA |
284 | /* |
285 | * Revalidate the write permissions, in case security policy has | |
286 | * changed since the files were opened. | |
287 | */ | |
288 | ret = security_file_permission(file, MAY_WRITE); | |
289 | if (ret) | |
3e63cbb1 | 290 | return ret; |
97ac7350 | 291 | |
97ac7350 | 292 | if (S_ISFIFO(inode->i_mode)) |
3e63cbb1 | 293 | return -ESPIPE; |
97ac7350 | 294 | |
9e79b132 AG |
295 | if (S_ISDIR(inode->i_mode)) |
296 | return -EISDIR; | |
297 | ||
298 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) | |
3e63cbb1 | 299 | return -ENODEV; |
97ac7350 | 300 | |
97ac7350 AA |
301 | /* Check for wrap through zero too */ |
302 | if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0)) | |
3e63cbb1 | 303 | return -EFBIG; |
97ac7350 | 304 | |
2fe17c10 | 305 | if (!file->f_op->fallocate) |
3e63cbb1 | 306 | return -EOPNOTSUPP; |
97ac7350 | 307 | |
bfe219d3 | 308 | file_start_write(file); |
14da9200 | 309 | ret = file->f_op->fallocate(file, mode, offset, len); |
820c12d5 HS |
310 | |
311 | /* | |
312 | * Create inotify and fanotify events. | |
313 | * | |
314 | * To keep the logic simple always create events if fallocate succeeds. | |
315 | * This implies that events are even created if the file size remains | |
316 | * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE. | |
317 | */ | |
318 | if (ret == 0) | |
319 | fsnotify_modify(file); | |
320 | ||
bfe219d3 | 321 | file_end_write(file); |
14da9200 | 322 | return ret; |
3e63cbb1 | 323 | } |
72c72bdf | 324 | EXPORT_SYMBOL_GPL(vfs_fallocate); |
3e63cbb1 | 325 | |
edf292c7 | 326 | int ksys_fallocate(int fd, int mode, loff_t offset, loff_t len) |
3e63cbb1 | 327 | { |
2903ff01 | 328 | struct fd f = fdget(fd); |
3e63cbb1 AJ |
329 | int error = -EBADF; |
330 | ||
2903ff01 | 331 | if (f.file) { |
72c72bdf | 332 | error = vfs_fallocate(f.file, mode, offset, len); |
2903ff01 | 333 | fdput(f); |
3e63cbb1 | 334 | } |
3e63cbb1 | 335 | return error; |
97ac7350 | 336 | } |
3e63cbb1 | 337 | |
edf292c7 DB |
338 | SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len) |
339 | { | |
340 | return ksys_fallocate(fd, mode, offset, len); | |
341 | } | |
342 | ||
1da177e4 LT |
343 | /* |
344 | * access() needs to use the real uid/gid, not the effective uid/gid. | |
345 | * We do this by temporarily clearing all FS-related capabilities and | |
346 | * switching the fsuid/fsgid around to the real ones. | |
347 | */ | |
94704515 | 348 | static const struct cred *access_override_creds(void) |
1da177e4 | 349 | { |
d84f4f99 DH |
350 | const struct cred *old_cred; |
351 | struct cred *override_cred; | |
1da177e4 | 352 | |
d84f4f99 DH |
353 | override_cred = prepare_creds(); |
354 | if (!override_cred) | |
94704515 | 355 | return NULL; |
1da177e4 | 356 | |
d84f4f99 DH |
357 | override_cred->fsuid = override_cred->uid; |
358 | override_cred->fsgid = override_cred->gid; | |
1da177e4 | 359 | |
086f7316 | 360 | if (!issecure(SECURE_NO_SETUID_FIXUP)) { |
1cdcbec1 | 361 | /* Clear the capabilities if we switch to a non-root user */ |
18815a18 EB |
362 | kuid_t root_uid = make_kuid(override_cred->user_ns, 0); |
363 | if (!uid_eq(override_cred->uid, root_uid)) | |
d84f4f99 | 364 | cap_clear(override_cred->cap_effective); |
086f7316 | 365 | else |
d84f4f99 DH |
366 | override_cred->cap_effective = |
367 | override_cred->cap_permitted; | |
086f7316 | 368 | } |
1da177e4 | 369 | |
d7852fbd LT |
370 | /* |
371 | * The new set of credentials can *only* be used in | |
372 | * task-synchronous circumstances, and does not need | |
373 | * RCU freeing, unless somebody then takes a separate | |
374 | * reference to it. | |
375 | * | |
376 | * NOTE! This is _only_ true because this credential | |
377 | * is used purely for override_creds() that installs | |
378 | * it as the subjective cred. Other threads will be | |
379 | * accessing ->real_cred, not the subjective cred. | |
380 | * | |
381 | * If somebody _does_ make a copy of this (using the | |
382 | * 'get_current_cred()' function), that will clear the | |
383 | * non_rcu field, because now that other user may be | |
384 | * expecting RCU freeing. But normal thread-synchronous | |
385 | * cred accesses will keep things non-RCY. | |
386 | */ | |
387 | override_cred->non_rcu = 1; | |
388 | ||
d84f4f99 | 389 | old_cred = override_creds(override_cred); |
94704515 MS |
390 | |
391 | /* override_cred() gets its own ref */ | |
392 | put_cred(override_cred); | |
393 | ||
394 | return old_cred; | |
395 | } | |
396 | ||
397 | long do_faccessat(int dfd, const char __user *filename, int mode) | |
398 | { | |
399 | struct path path; | |
400 | struct inode *inode; | |
401 | int res; | |
402 | unsigned int lookup_flags = LOOKUP_FOLLOW; | |
403 | const struct cred *old_cred; | |
404 | ||
405 | if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ | |
406 | return -EINVAL; | |
407 | ||
408 | old_cred = access_override_creds(); | |
409 | if (!old_cred) | |
410 | return -ENOMEM; | |
411 | ||
87fa5595 JL |
412 | retry: |
413 | res = user_path_at(dfd, filename, lookup_flags, &path); | |
6902d925 DH |
414 | if (res) |
415 | goto out; | |
416 | ||
63afdfc7 | 417 | inode = d_backing_inode(path.dentry); |
256984a8 AV |
418 | |
419 | if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) { | |
30524472 AV |
420 | /* |
421 | * MAY_EXEC on regular files is denied if the fs is mounted | |
422 | * with the "noexec" flag. | |
423 | */ | |
424 | res = -EACCES; | |
90f8572b | 425 | if (path_noexec(&path)) |
30524472 AV |
426 | goto out_path_release; |
427 | } | |
428 | ||
256984a8 | 429 | res = inode_permission(inode, mode | MAY_ACCESS); |
6902d925 | 430 | /* SuS v2 requires we report a read only fs too */ |
256984a8 | 431 | if (res || !(mode & S_IWOTH) || special_file(inode->i_mode)) |
6902d925 | 432 | goto out_path_release; |
2f676cbc DH |
433 | /* |
434 | * This is a rare case where using __mnt_is_readonly() | |
435 | * is OK without a mnt_want/drop_write() pair. Since | |
436 | * no actual write to the fs is performed here, we do | |
437 | * not need to telegraph to that to anyone. | |
438 | * | |
439 | * By doing this, we accept that this access is | |
440 | * inherently racy and know that the fs may change | |
441 | * state before we even see this result. | |
442 | */ | |
2d8f3038 | 443 | if (__mnt_is_readonly(path.mnt)) |
6902d925 | 444 | res = -EROFS; |
1da177e4 | 445 | |
6902d925 | 446 | out_path_release: |
2d8f3038 | 447 | path_put(&path); |
87fa5595 JL |
448 | if (retry_estale(res, lookup_flags)) { |
449 | lookup_flags |= LOOKUP_REVAL; | |
450 | goto retry; | |
451 | } | |
6902d925 | 452 | out: |
d84f4f99 | 453 | revert_creds(old_cred); |
1da177e4 LT |
454 | return res; |
455 | } | |
456 | ||
cbfe20f5 DB |
457 | SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode) |
458 | { | |
459 | return do_faccessat(dfd, filename, mode); | |
460 | } | |
461 | ||
ca013e94 | 462 | SYSCALL_DEFINE2(access, const char __user *, filename, int, mode) |
5590ff0d | 463 | { |
cbfe20f5 | 464 | return do_faccessat(AT_FDCWD, filename, mode); |
5590ff0d UD |
465 | } |
466 | ||
447016e9 | 467 | int ksys_chdir(const char __user *filename) |
1da177e4 | 468 | { |
2d8f3038 | 469 | struct path path; |
1da177e4 | 470 | int error; |
0291c0a5 JL |
471 | unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
472 | retry: | |
473 | error = user_path_at(AT_FDCWD, filename, lookup_flags, &path); | |
1da177e4 LT |
474 | if (error) |
475 | goto out; | |
476 | ||
9cfcac81 | 477 | error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); |
1da177e4 LT |
478 | if (error) |
479 | goto dput_and_out; | |
480 | ||
2d8f3038 | 481 | set_fs_pwd(current->fs, &path); |
1da177e4 LT |
482 | |
483 | dput_and_out: | |
2d8f3038 | 484 | path_put(&path); |
0291c0a5 JL |
485 | if (retry_estale(error, lookup_flags)) { |
486 | lookup_flags |= LOOKUP_REVAL; | |
487 | goto retry; | |
488 | } | |
1da177e4 LT |
489 | out: |
490 | return error; | |
491 | } | |
492 | ||
447016e9 DB |
493 | SYSCALL_DEFINE1(chdir, const char __user *, filename) |
494 | { | |
495 | return ksys_chdir(filename); | |
496 | } | |
497 | ||
3cdad428 | 498 | SYSCALL_DEFINE1(fchdir, unsigned int, fd) |
1da177e4 | 499 | { |
2903ff01 | 500 | struct fd f = fdget_raw(fd); |
159b0956 | 501 | int error; |
1da177e4 LT |
502 | |
503 | error = -EBADF; | |
2903ff01 | 504 | if (!f.file) |
1da177e4 LT |
505 | goto out; |
506 | ||
1da177e4 | 507 | error = -ENOTDIR; |
159b0956 | 508 | if (!d_can_lookup(f.file->f_path.dentry)) |
1da177e4 LT |
509 | goto out_putf; |
510 | ||
159b0956 | 511 | error = inode_permission(file_inode(f.file), MAY_EXEC | MAY_CHDIR); |
1da177e4 | 512 | if (!error) |
2903ff01 | 513 | set_fs_pwd(current->fs, &f.file->f_path); |
1da177e4 | 514 | out_putf: |
2903ff01 | 515 | fdput(f); |
1da177e4 LT |
516 | out: |
517 | return error; | |
518 | } | |
519 | ||
a16fe33a | 520 | int ksys_chroot(const char __user *filename) |
1da177e4 | 521 | { |
2d8f3038 | 522 | struct path path; |
1da177e4 | 523 | int error; |
2771261e JL |
524 | unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
525 | retry: | |
526 | error = user_path_at(AT_FDCWD, filename, lookup_flags, &path); | |
1da177e4 LT |
527 | if (error) |
528 | goto out; | |
529 | ||
9cfcac81 | 530 | error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); |
1da177e4 LT |
531 | if (error) |
532 | goto dput_and_out; | |
533 | ||
534 | error = -EPERM; | |
c7b96acf | 535 | if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT)) |
1da177e4 | 536 | goto dput_and_out; |
8b8efb44 TH |
537 | error = security_path_chroot(&path); |
538 | if (error) | |
539 | goto dput_and_out; | |
1da177e4 | 540 | |
2d8f3038 | 541 | set_fs_root(current->fs, &path); |
1da177e4 LT |
542 | error = 0; |
543 | dput_and_out: | |
2d8f3038 | 544 | path_put(&path); |
2771261e JL |
545 | if (retry_estale(error, lookup_flags)) { |
546 | lookup_flags |= LOOKUP_REVAL; | |
547 | goto retry; | |
548 | } | |
1da177e4 LT |
549 | out: |
550 | return error; | |
551 | } | |
552 | ||
a16fe33a DB |
553 | SYSCALL_DEFINE1(chroot, const char __user *, filename) |
554 | { | |
555 | return ksys_chroot(filename); | |
556 | } | |
557 | ||
be01f9f2 | 558 | static int chmod_common(const struct path *path, umode_t mode) |
1da177e4 | 559 | { |
e57712eb | 560 | struct inode *inode = path->dentry->d_inode; |
27ac0ffe | 561 | struct inode *delegated_inode = NULL; |
1da177e4 | 562 | struct iattr newattrs; |
e57712eb | 563 | int error; |
1da177e4 | 564 | |
e57712eb AV |
565 | error = mnt_want_write(path->mnt); |
566 | if (error) | |
567 | return error; | |
27ac0ffe | 568 | retry_deleg: |
5955102c | 569 | inode_lock(inode); |
cdcf116d | 570 | error = security_path_chmod(path, mode); |
e57712eb | 571 | if (error) |
fe542cf5 | 572 | goto out_unlock; |
1da177e4 LT |
573 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); |
574 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
27ac0ffe | 575 | error = notify_change(path->dentry, &newattrs, &delegated_inode); |
fe542cf5 | 576 | out_unlock: |
5955102c | 577 | inode_unlock(inode); |
27ac0ffe BF |
578 | if (delegated_inode) { |
579 | error = break_deleg_wait(&delegated_inode); | |
580 | if (!error) | |
581 | goto retry_deleg; | |
582 | } | |
e57712eb AV |
583 | mnt_drop_write(path->mnt); |
584 | return error; | |
585 | } | |
586 | ||
03450e27 | 587 | int ksys_fchmod(unsigned int fd, umode_t mode) |
e57712eb | 588 | { |
173c8401 | 589 | struct fd f = fdget(fd); |
e57712eb AV |
590 | int err = -EBADF; |
591 | ||
173c8401 | 592 | if (f.file) { |
9f45f5bf | 593 | audit_file(f.file); |
173c8401 AV |
594 | err = chmod_common(&f.file->f_path, mode); |
595 | fdput(f); | |
e57712eb | 596 | } |
1da177e4 LT |
597 | return err; |
598 | } | |
599 | ||
03450e27 DB |
600 | SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode) |
601 | { | |
602 | return ksys_fchmod(fd, mode); | |
603 | } | |
604 | ||
605 | int do_fchmodat(int dfd, const char __user *filename, umode_t mode) | |
1da177e4 | 606 | { |
2d8f3038 | 607 | struct path path; |
1da177e4 | 608 | int error; |
14ff690c JL |
609 | unsigned int lookup_flags = LOOKUP_FOLLOW; |
610 | retry: | |
611 | error = user_path_at(dfd, filename, lookup_flags, &path); | |
e57712eb AV |
612 | if (!error) { |
613 | error = chmod_common(&path, mode); | |
614 | path_put(&path); | |
14ff690c JL |
615 | if (retry_estale(error, lookup_flags)) { |
616 | lookup_flags |= LOOKUP_REVAL; | |
617 | goto retry; | |
618 | } | |
e57712eb | 619 | } |
1da177e4 LT |
620 | return error; |
621 | } | |
622 | ||
03450e27 DB |
623 | SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, |
624 | umode_t, mode) | |
625 | { | |
626 | return do_fchmodat(dfd, filename, mode); | |
627 | } | |
628 | ||
49f0a076 | 629 | SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode) |
5590ff0d | 630 | { |
03450e27 | 631 | return do_fchmodat(AT_FDCWD, filename, mode); |
5590ff0d UD |
632 | } |
633 | ||
7fd25dac | 634 | static int chown_common(const struct path *path, uid_t user, gid_t group) |
1da177e4 | 635 | { |
fe542cf5 | 636 | struct inode *inode = path->dentry->d_inode; |
27ac0ffe | 637 | struct inode *delegated_inode = NULL; |
1da177e4 LT |
638 | int error; |
639 | struct iattr newattrs; | |
52137abe EB |
640 | kuid_t uid; |
641 | kgid_t gid; | |
642 | ||
643 | uid = make_kuid(current_user_ns(), user); | |
644 | gid = make_kgid(current_user_ns(), group); | |
1da177e4 | 645 | |
c1b8940b | 646 | retry_deleg: |
1da177e4 LT |
647 | newattrs.ia_valid = ATTR_CTIME; |
648 | if (user != (uid_t) -1) { | |
52137abe EB |
649 | if (!uid_valid(uid)) |
650 | return -EINVAL; | |
1da177e4 | 651 | newattrs.ia_valid |= ATTR_UID; |
52137abe | 652 | newattrs.ia_uid = uid; |
1da177e4 LT |
653 | } |
654 | if (group != (gid_t) -1) { | |
52137abe EB |
655 | if (!gid_valid(gid)) |
656 | return -EINVAL; | |
1da177e4 | 657 | newattrs.ia_valid |= ATTR_GID; |
52137abe | 658 | newattrs.ia_gid = gid; |
1da177e4 LT |
659 | } |
660 | if (!S_ISDIR(inode->i_mode)) | |
b5376771 SH |
661 | newattrs.ia_valid |= |
662 | ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV; | |
5955102c | 663 | inode_lock(inode); |
d2b31ca6 | 664 | error = security_path_chown(path, uid, gid); |
fe542cf5 | 665 | if (!error) |
27ac0ffe | 666 | error = notify_change(path->dentry, &newattrs, &delegated_inode); |
5955102c | 667 | inode_unlock(inode); |
27ac0ffe BF |
668 | if (delegated_inode) { |
669 | error = break_deleg_wait(&delegated_inode); | |
670 | if (!error) | |
671 | goto retry_deleg; | |
672 | } | |
1da177e4 LT |
673 | return error; |
674 | } | |
675 | ||
55731b3c DB |
676 | int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group, |
677 | int flag) | |
5590ff0d | 678 | { |
2d8f3038 | 679 | struct path path; |
5590ff0d | 680 | int error = -EINVAL; |
65cfc672 | 681 | int lookup_flags; |
5590ff0d | 682 | |
65cfc672 | 683 | if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) |
5590ff0d UD |
684 | goto out; |
685 | ||
65cfc672 AV |
686 | lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; |
687 | if (flag & AT_EMPTY_PATH) | |
688 | lookup_flags |= LOOKUP_EMPTY; | |
99a5df37 | 689 | retry: |
65cfc672 | 690 | error = user_path_at(dfd, filename, lookup_flags, &path); |
6902d925 DH |
691 | if (error) |
692 | goto out; | |
2d8f3038 | 693 | error = mnt_want_write(path.mnt); |
2af482a7 DH |
694 | if (error) |
695 | goto out_release; | |
fe542cf5 | 696 | error = chown_common(&path, user, group); |
2d8f3038 | 697 | mnt_drop_write(path.mnt); |
2af482a7 | 698 | out_release: |
2d8f3038 | 699 | path_put(&path); |
99a5df37 JL |
700 | if (retry_estale(error, lookup_flags)) { |
701 | lookup_flags |= LOOKUP_REVAL; | |
702 | goto retry; | |
703 | } | |
5590ff0d UD |
704 | out: |
705 | return error; | |
706 | } | |
707 | ||
55731b3c DB |
708 | SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user, |
709 | gid_t, group, int, flag) | |
710 | { | |
711 | return do_fchownat(dfd, filename, user, group, flag); | |
712 | } | |
713 | ||
55e4def0 | 714 | SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group) |
1da177e4 | 715 | { |
55731b3c | 716 | return do_fchownat(AT_FDCWD, filename, user, group, 0); |
55e4def0 | 717 | } |
1da177e4 | 718 | |
55e4def0 DH |
719 | SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group) |
720 | { | |
55731b3c DB |
721 | return do_fchownat(AT_FDCWD, filename, user, group, |
722 | AT_SYMLINK_NOFOLLOW); | |
1da177e4 LT |
723 | } |
724 | ||
55731b3c | 725 | int ksys_fchown(unsigned int fd, uid_t user, gid_t group) |
1da177e4 | 726 | { |
2903ff01 | 727 | struct fd f = fdget(fd); |
1da177e4 LT |
728 | int error = -EBADF; |
729 | ||
2903ff01 | 730 | if (!f.file) |
6902d925 DH |
731 | goto out; |
732 | ||
6742cee0 | 733 | error = mnt_want_write_file(f.file); |
2af482a7 DH |
734 | if (error) |
735 | goto out_fput; | |
9f45f5bf | 736 | audit_file(f.file); |
2903ff01 | 737 | error = chown_common(&f.file->f_path, user, group); |
6742cee0 | 738 | mnt_drop_write_file(f.file); |
2af482a7 | 739 | out_fput: |
2903ff01 | 740 | fdput(f); |
6902d925 | 741 | out: |
1da177e4 LT |
742 | return error; |
743 | } | |
744 | ||
55731b3c DB |
745 | SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group) |
746 | { | |
747 | return ksys_fchown(fd, user, group); | |
748 | } | |
749 | ||
02e5180d | 750 | static int do_dentry_open(struct file *f, |
4bacc9c9 | 751 | struct inode *inode, |
ae2bb293 | 752 | int (*open)(struct inode *, struct file *)) |
1da177e4 | 753 | { |
1abf0c71 | 754 | static const struct file_operations empty_fops = {}; |
1da177e4 LT |
755 | int error; |
756 | ||
b5bcdda3 | 757 | path_get(&f->f_path); |
4bacc9c9 | 758 | f->f_inode = inode; |
1da177e4 | 759 | f->f_mapping = inode->i_mapping; |
1da177e4 | 760 | |
5660e13d JL |
761 | /* Ensure that we skip any errors that predate opening of the file */ |
762 | f->f_wb_err = filemap_sample_wb_err(f->f_mapping); | |
763 | ||
3f4d5a00 | 764 | if (unlikely(f->f_flags & O_PATH)) { |
f5d11409 | 765 | f->f_mode = FMODE_PATH | FMODE_OPENED; |
1abf0c71 | 766 | f->f_op = &empty_fops; |
af04fadc | 767 | return 0; |
1abf0c71 AV |
768 | } |
769 | ||
73601ea5 TH |
770 | /* Any file opened for execve()/uselib() has to be a regular file. */ |
771 | if (unlikely(f->f_flags & FMODE_EXEC && !S_ISREG(inode->i_mode))) { | |
772 | error = -EACCES; | |
773 | goto cleanup_file; | |
774 | } | |
775 | ||
dd20908a | 776 | if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) { |
0ccb2863 | 777 | error = get_write_access(inode); |
3f4d5a00 | 778 | if (unlikely(error)) |
1da177e4 | 779 | goto cleanup_file; |
0ccb2863 | 780 | error = __mnt_want_write(f->f_path.mnt); |
3f4d5a00 | 781 | if (unlikely(error)) { |
0ccb2863 AV |
782 | put_write_access(inode); |
783 | goto cleanup_file; | |
784 | } | |
83f936c7 | 785 | f->f_mode |= FMODE_WRITER; |
1da177e4 LT |
786 | } |
787 | ||
2be7d348 LT |
788 | /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */ |
789 | if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)) | |
790 | f->f_mode |= FMODE_ATOMIC_POS; | |
791 | ||
1abf0c71 | 792 | f->f_op = fops_get(inode->i_fop); |
7159d544 | 793 | if (WARN_ON(!f->f_op)) { |
72c2d531 AV |
794 | error = -ENODEV; |
795 | goto cleanup_all; | |
796 | } | |
1abf0c71 | 797 | |
e3f20ae2 | 798 | error = security_file_open(f); |
788e7dd4 YN |
799 | if (error) |
800 | goto cleanup_all; | |
801 | ||
c568d683 | 802 | error = break_lease(locks_inode(f), f->f_flags); |
f3c7691e BF |
803 | if (error) |
804 | goto cleanup_all; | |
805 | ||
ea73ea72 AV |
806 | /* normally all 3 are set; ->open() can clear them if needed */ |
807 | f->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; | |
72c2d531 | 808 | if (!open) |
834f2a4a TM |
809 | open = f->f_op->open; |
810 | if (open) { | |
811 | error = open(inode, f); | |
1da177e4 LT |
812 | if (error) |
813 | goto cleanup_all; | |
814 | } | |
f5d11409 | 815 | f->f_mode |= FMODE_OPENED; |
890275b5 MZ |
816 | if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) |
817 | i_readcount_inc(inode); | |
293bc982 | 818 | if ((f->f_mode & FMODE_READ) && |
84363182 | 819 | likely(f->f_op->read || f->f_op->read_iter)) |
7f7f25e8 | 820 | f->f_mode |= FMODE_CAN_READ; |
293bc982 | 821 | if ((f->f_mode & FMODE_WRITE) && |
84363182 | 822 | likely(f->f_op->write || f->f_op->write_iter)) |
7f7f25e8 | 823 | f->f_mode |= FMODE_CAN_WRITE; |
834f2a4a | 824 | |
c75b1d94 | 825 | f->f_write_hint = WRITE_LIFE_NOT_SET; |
1da177e4 LT |
826 | f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); |
827 | ||
828 | file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); | |
af04fadc | 829 | |
69527c55 AV |
830 | /* NB: we're sure to have correct a_ops only after f_op->open */ |
831 | if (f->f_flags & O_DIRECT) { | |
832 | if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) | |
833 | return -EINVAL; | |
834 | } | |
09d91cda SL |
835 | |
836 | /* | |
837 | * XXX: Huge page cache doesn't support writing yet. Drop all page | |
838 | * cache for this file before processing writes. | |
839 | */ | |
840 | if ((f->f_mode & FMODE_WRITE) && filemap_nr_thps(inode->i_mapping)) | |
841 | truncate_pagecache(inode, 0); | |
842 | ||
96b7e579 | 843 | return 0; |
1da177e4 LT |
844 | |
845 | cleanup_all: | |
6b4e8085 AV |
846 | if (WARN_ON_ONCE(error > 0)) |
847 | error = -EINVAL; | |
1da177e4 | 848 | fops_put(f->f_op); |
83f936c7 | 849 | if (f->f_mode & FMODE_WRITER) { |
1da177e4 | 850 | put_write_access(inode); |
83f936c7 | 851 | __mnt_drop_write(f->f_path.mnt); |
4a3fd211 | 852 | } |
1da177e4 | 853 | cleanup_file: |
02e5180d AV |
854 | path_put(&f->f_path); |
855 | f->f_path.mnt = NULL; | |
856 | f->f_path.dentry = NULL; | |
dd37978c | 857 | f->f_inode = NULL; |
96b7e579 | 858 | return error; |
1da177e4 LT |
859 | } |
860 | ||
d18e9008 MS |
861 | /** |
862 | * finish_open - finish opening a file | |
0854d450 | 863 | * @file: file pointer |
d18e9008 MS |
864 | * @dentry: pointer to dentry |
865 | * @open: open callback | |
0854d450 | 866 | * @opened: state of open |
d18e9008 MS |
867 | * |
868 | * This can be used to finish opening a file passed to i_op->atomic_open(). | |
869 | * | |
870 | * If the open callback is set to NULL, then the standard f_op->open() | |
871 | * filesystem callback is substituted. | |
0854d450 MS |
872 | * |
873 | * NB: the dentry reference is _not_ consumed. If, for example, the dentry is | |
874 | * the return value of d_splice_alias(), then the caller needs to perform dput() | |
875 | * on it after finish_open(). | |
876 | * | |
0854d450 | 877 | * Returns zero on success or -errno if the open failed. |
d18e9008 | 878 | */ |
30d90494 | 879 | int finish_open(struct file *file, struct dentry *dentry, |
be12af3e | 880 | int (*open)(struct inode *, struct file *)) |
d18e9008 | 881 | { |
aad888f8 | 882 | BUG_ON(file->f_mode & FMODE_OPENED); /* once it's opened, it's opened */ |
d18e9008 | 883 | |
b5bcdda3 | 884 | file->f_path.dentry = dentry; |
aad888f8 | 885 | return do_dentry_open(file, d_backing_inode(dentry), open); |
d18e9008 MS |
886 | } |
887 | EXPORT_SYMBOL(finish_open); | |
888 | ||
889 | /** | |
890 | * finish_no_open - finish ->atomic_open() without opening the file | |
891 | * | |
0854d450 | 892 | * @file: file pointer |
d18e9008 MS |
893 | * @dentry: dentry or NULL (as returned from ->lookup()) |
894 | * | |
895 | * This can be used to set the result of a successful lookup in ->atomic_open(). | |
0854d450 MS |
896 | * |
897 | * NB: unlike finish_open() this function does consume the dentry reference and | |
898 | * the caller need not dput() it. | |
899 | * | |
64e1ac4d | 900 | * Returns "0" which must be the return value of ->atomic_open() after having |
0854d450 | 901 | * called this function. |
d18e9008 | 902 | */ |
e45198a6 | 903 | int finish_no_open(struct file *file, struct dentry *dentry) |
d18e9008 | 904 | { |
30d90494 | 905 | file->f_path.dentry = dentry; |
64e1ac4d | 906 | return 0; |
d18e9008 MS |
907 | } |
908 | EXPORT_SYMBOL(finish_no_open); | |
909 | ||
9bf39ab2 MS |
910 | char *file_path(struct file *filp, char *buf, int buflen) |
911 | { | |
912 | return d_path(&filp->f_path, buf, buflen); | |
913 | } | |
914 | EXPORT_SYMBOL(file_path); | |
915 | ||
4bacc9c9 DH |
916 | /** |
917 | * vfs_open - open the file at the given path | |
918 | * @path: path to open | |
919 | * @file: newly allocated file with f_flag initialized | |
920 | * @cred: credentials to use | |
921 | */ | |
ae2bb293 | 922 | int vfs_open(const struct path *path, struct file *file) |
4bacc9c9 | 923 | { |
54d5ca87 | 924 | file->f_path = *path; |
a6518f73 | 925 | return do_dentry_open(file, d_backing_inode(path->dentry), NULL); |
4bacc9c9 DH |
926 | } |
927 | ||
765927b2 | 928 | struct file *dentry_open(const struct path *path, int flags, |
745ca247 | 929 | const struct cred *cred) |
a1a5b3d9 PS |
930 | { |
931 | int error; | |
932 | struct file *f; | |
933 | ||
e0e81739 DH |
934 | validate_creds(cred); |
935 | ||
c212f9aa | 936 | /* We must always pass in a valid mount pointer. */ |
765927b2 | 937 | BUG_ON(!path->mnt); |
322ee5b3 | 938 | |
ea73ea72 | 939 | f = alloc_empty_file(flags, cred); |
af04fadc | 940 | if (!IS_ERR(f)) { |
ae2bb293 | 941 | error = vfs_open(path, f); |
4d27f326 AV |
942 | if (error) { |
943 | fput(f); | |
af04fadc AV |
944 | f = ERR_PTR(error); |
945 | } | |
2a027e7a AV |
946 | } |
947 | return f; | |
a1a5b3d9 | 948 | } |
1da177e4 LT |
949 | EXPORT_SYMBOL(dentry_open); |
950 | ||
2abc77af AV |
951 | struct file *open_with_fake_path(const struct path *path, int flags, |
952 | struct inode *inode, const struct cred *cred) | |
953 | { | |
d3b1084d | 954 | struct file *f = alloc_empty_file_noaccount(flags, cred); |
2abc77af AV |
955 | if (!IS_ERR(f)) { |
956 | int error; | |
957 | ||
958 | f->f_path = *path; | |
959 | error = do_dentry_open(f, inode, NULL); | |
960 | if (error) { | |
961 | fput(f); | |
962 | f = ERR_PTR(error); | |
963 | } | |
964 | } | |
965 | return f; | |
966 | } | |
967 | EXPORT_SYMBOL(open_with_fake_path); | |
968 | ||
fddb5d43 AS |
969 | #define WILL_CREATE(flags) (flags & (O_CREAT | __O_TMPFILE)) |
970 | #define O_PATH_FLAGS (O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC) | |
971 | ||
35cb6d54 | 972 | inline struct open_how build_open_how(int flags, umode_t mode) |
fddb5d43 AS |
973 | { |
974 | struct open_how how = { | |
975 | .flags = flags & VALID_OPEN_FLAGS, | |
976 | .mode = mode & S_IALLUGO, | |
977 | }; | |
978 | ||
979 | /* O_PATH beats everything else. */ | |
980 | if (how.flags & O_PATH) | |
981 | how.flags &= O_PATH_FLAGS; | |
982 | /* Modes should only be set for create-like flags. */ | |
983 | if (!WILL_CREATE(how.flags)) | |
984 | how.mode = 0; | |
985 | return how; | |
986 | } | |
987 | ||
35cb6d54 | 988 | inline int build_open_flags(const struct open_how *how, struct open_flags *op) |
47c805dc | 989 | { |
fddb5d43 | 990 | int flags = how->flags; |
47c805dc | 991 | int lookup_flags = 0; |
62fb4a15 | 992 | int acc_mode = ACC_MODE(flags); |
47c805dc | 993 | |
fddb5d43 AS |
994 | /* Must never be set by userspace */ |
995 | flags &= ~(FMODE_NONOTIFY | O_CLOEXEC); | |
996 | ||
629e014b | 997 | /* |
fddb5d43 AS |
998 | * Older syscalls implicitly clear all of the invalid flags or argument |
999 | * values before calling build_open_flags(), but openat2(2) checks all | |
1000 | * of its arguments. | |
629e014b | 1001 | */ |
fddb5d43 AS |
1002 | if (flags & ~VALID_OPEN_FLAGS) |
1003 | return -EINVAL; | |
1004 | if (how->resolve & ~VALID_RESOLVE_FLAGS) | |
1005 | return -EINVAL; | |
629e014b | 1006 | |
fddb5d43 AS |
1007 | /* Deal with the mode. */ |
1008 | if (WILL_CREATE(flags)) { | |
1009 | if (how->mode & ~S_IALLUGO) | |
1010 | return -EINVAL; | |
1011 | op->mode = how->mode | S_IFREG; | |
1012 | } else { | |
1013 | if (how->mode != 0) | |
1014 | return -EINVAL; | |
e68726ff | 1015 | op->mode = 0; |
fddb5d43 | 1016 | } |
47c805dc AV |
1017 | |
1018 | /* | |
fddb5d43 AS |
1019 | * In order to ensure programs get explicit errors when trying to use |
1020 | * O_TMPFILE on old kernels, O_TMPFILE is implemented such that it | |
1021 | * looks like (O_DIRECTORY|O_RDWR & ~O_CREAT) to old kernels. But we | |
1022 | * have to require userspace to explicitly set it. | |
47c805dc | 1023 | */ |
bb458c64 AV |
1024 | if (flags & __O_TMPFILE) { |
1025 | if ((flags & O_TMPFILE_MASK) != O_TMPFILE) | |
60545d0d | 1026 | return -EINVAL; |
ba57ea64 AV |
1027 | if (!(acc_mode & MAY_WRITE)) |
1028 | return -EINVAL; | |
fddb5d43 AS |
1029 | } |
1030 | if (flags & O_PATH) { | |
1031 | /* O_PATH only permits certain other flags to be set. */ | |
1032 | if (flags & ~O_PATH_FLAGS) | |
1033 | return -EINVAL; | |
1abf0c71 | 1034 | acc_mode = 0; |
1abf0c71 | 1035 | } |
47c805dc | 1036 | |
fddb5d43 AS |
1037 | /* |
1038 | * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only | |
1039 | * check for O_DSYNC if the need any syncing at all we enforce it's | |
1040 | * always set instead of having to deal with possibly weird behaviour | |
1041 | * for malicious applications setting only __O_SYNC. | |
1042 | */ | |
1043 | if (flags & __O_SYNC) | |
1044 | flags |= O_DSYNC; | |
1045 | ||
1abf0c71 | 1046 | op->open_flag = flags; |
47c805dc AV |
1047 | |
1048 | /* O_TRUNC implies we need access checks for write permissions */ | |
1049 | if (flags & O_TRUNC) | |
1050 | acc_mode |= MAY_WRITE; | |
1051 | ||
1052 | /* Allow the LSM permission hook to distinguish append | |
1053 | access from general write access. */ | |
1054 | if (flags & O_APPEND) | |
1055 | acc_mode |= MAY_APPEND; | |
1056 | ||
1057 | op->acc_mode = acc_mode; | |
1058 | ||
1abf0c71 AV |
1059 | op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN; |
1060 | ||
47c805dc AV |
1061 | if (flags & O_CREAT) { |
1062 | op->intent |= LOOKUP_CREATE; | |
31d1726d | 1063 | if (flags & O_EXCL) { |
47c805dc | 1064 | op->intent |= LOOKUP_EXCL; |
31d1726d AV |
1065 | flags |= O_NOFOLLOW; |
1066 | } | |
47c805dc AV |
1067 | } |
1068 | ||
1069 | if (flags & O_DIRECTORY) | |
1070 | lookup_flags |= LOOKUP_DIRECTORY; | |
1071 | if (!(flags & O_NOFOLLOW)) | |
1072 | lookup_flags |= LOOKUP_FOLLOW; | |
fddb5d43 AS |
1073 | |
1074 | if (how->resolve & RESOLVE_NO_XDEV) | |
1075 | lookup_flags |= LOOKUP_NO_XDEV; | |
1076 | if (how->resolve & RESOLVE_NO_MAGICLINKS) | |
1077 | lookup_flags |= LOOKUP_NO_MAGICLINKS; | |
1078 | if (how->resolve & RESOLVE_NO_SYMLINKS) | |
1079 | lookup_flags |= LOOKUP_NO_SYMLINKS; | |
1080 | if (how->resolve & RESOLVE_BENEATH) | |
1081 | lookup_flags |= LOOKUP_BENEATH; | |
1082 | if (how->resolve & RESOLVE_IN_ROOT) | |
1083 | lookup_flags |= LOOKUP_IN_ROOT; | |
1084 | ||
f9652e10 AV |
1085 | op->lookup_flags = lookup_flags; |
1086 | return 0; | |
47c805dc AV |
1087 | } |
1088 | ||
669abf4e JL |
1089 | /** |
1090 | * file_open_name - open file and return file pointer | |
1091 | * | |
1092 | * @name: struct filename containing path to open | |
1093 | * @flags: open flags as per the open(2) second argument | |
1094 | * @mode: mode for the new file if O_CREAT is set, else ignored | |
1095 | * | |
1096 | * This is the helper to open a file from kernelspace if you really | |
1097 | * have to. But in generally you should not do this, so please move | |
1098 | * along, nothing to see here.. | |
1099 | */ | |
1100 | struct file *file_open_name(struct filename *name, int flags, umode_t mode) | |
1101 | { | |
1102 | struct open_flags op; | |
fddb5d43 AS |
1103 | struct open_how how = build_open_how(flags, mode); |
1104 | int err = build_open_flags(&how, &op); | |
1105 | if (err) | |
1106 | return ERR_PTR(err); | |
1107 | return do_filp_open(AT_FDCWD, name, &op); | |
669abf4e JL |
1108 | } |
1109 | ||
47c805dc AV |
1110 | /** |
1111 | * filp_open - open file and return file pointer | |
1112 | * | |
1113 | * @filename: path to open | |
1114 | * @flags: open flags as per the open(2) second argument | |
1115 | * @mode: mode for the new file if O_CREAT is set, else ignored | |
1116 | * | |
1117 | * This is the helper to open a file from kernelspace if you really | |
1118 | * have to. But in generally you should not do this, so please move | |
1119 | * along, nothing to see here.. | |
1120 | */ | |
a218d0fd | 1121 | struct file *filp_open(const char *filename, int flags, umode_t mode) |
47c805dc | 1122 | { |
51689104 PM |
1123 | struct filename *name = getname_kernel(filename); |
1124 | struct file *file = ERR_CAST(name); | |
1125 | ||
1126 | if (!IS_ERR(name)) { | |
1127 | file = file_open_name(name, flags, mode); | |
1128 | putname(name); | |
1129 | } | |
1130 | return file; | |
47c805dc AV |
1131 | } |
1132 | EXPORT_SYMBOL(filp_open); | |
1133 | ||
73d049a4 | 1134 | struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt, |
378c6520 | 1135 | const char *filename, int flags, umode_t mode) |
73d049a4 AV |
1136 | { |
1137 | struct open_flags op; | |
fddb5d43 AS |
1138 | struct open_how how = build_open_how(flags, mode); |
1139 | int err = build_open_flags(&how, &op); | |
f9652e10 AV |
1140 | if (err) |
1141 | return ERR_PTR(err); | |
f9652e10 | 1142 | return do_file_open_root(dentry, mnt, filename, &op); |
73d049a4 AV |
1143 | } |
1144 | EXPORT_SYMBOL(file_open_root); | |
1145 | ||
fddb5d43 AS |
1146 | static long do_sys_openat2(int dfd, const char __user *filename, |
1147 | struct open_how *how) | |
1da177e4 | 1148 | { |
47c805dc | 1149 | struct open_flags op; |
fddb5d43 | 1150 | int fd = build_open_flags(how, &op); |
f9652e10 AV |
1151 | struct filename *tmp; |
1152 | ||
1153 | if (fd) | |
1154 | return fd; | |
1155 | ||
1156 | tmp = getname(filename); | |
1157 | if (IS_ERR(tmp)) | |
1158 | return PTR_ERR(tmp); | |
1159 | ||
fddb5d43 | 1160 | fd = get_unused_fd_flags(how->flags); |
f9652e10 AV |
1161 | if (fd >= 0) { |
1162 | struct file *f = do_filp_open(dfd, tmp, &op); | |
1163 | if (IS_ERR(f)) { | |
1164 | put_unused_fd(fd); | |
1165 | fd = PTR_ERR(f); | |
1166 | } else { | |
1167 | fsnotify_open(f); | |
1168 | fd_install(fd, f); | |
1da177e4 | 1169 | } |
1da177e4 | 1170 | } |
f9652e10 | 1171 | putname(tmp); |
1da177e4 | 1172 | return fd; |
1da177e4 | 1173 | } |
e922efc3 | 1174 | |
fddb5d43 | 1175 | long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode) |
e922efc3 | 1176 | { |
fddb5d43 AS |
1177 | struct open_how how = build_open_how(flags, mode); |
1178 | return do_sys_openat2(dfd, filename, &how); | |
1179 | } | |
e922efc3 | 1180 | |
fddb5d43 AS |
1181 | |
1182 | SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode) | |
1183 | { | |
1184 | return ksys_open(filename, flags, mode); | |
e922efc3 | 1185 | } |
1da177e4 | 1186 | |
6559eed8 | 1187 | SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, |
a218d0fd | 1188 | umode_t, mode) |
5590ff0d UD |
1189 | { |
1190 | if (force_o_largefile()) | |
1191 | flags |= O_LARGEFILE; | |
2cf09666 | 1192 | return do_sys_open(dfd, filename, flags, mode); |
5590ff0d | 1193 | } |
5590ff0d | 1194 | |
fddb5d43 AS |
1195 | SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename, |
1196 | struct open_how __user *, how, size_t, usize) | |
1197 | { | |
1198 | int err; | |
1199 | struct open_how tmp; | |
1200 | ||
1201 | BUILD_BUG_ON(sizeof(struct open_how) < OPEN_HOW_SIZE_VER0); | |
1202 | BUILD_BUG_ON(sizeof(struct open_how) != OPEN_HOW_SIZE_LATEST); | |
1203 | ||
1204 | if (unlikely(usize < OPEN_HOW_SIZE_VER0)) | |
1205 | return -EINVAL; | |
1206 | ||
1207 | err = copy_struct_from_user(&tmp, sizeof(tmp), how, usize); | |
1208 | if (err) | |
1209 | return err; | |
1210 | ||
1211 | /* O_LARGEFILE is only allowed for non-O_PATH. */ | |
1212 | if (!(tmp.flags & O_PATH) && force_o_largefile()) | |
1213 | tmp.flags |= O_LARGEFILE; | |
1214 | ||
1215 | return do_sys_openat2(dfd, filename, &tmp); | |
1216 | } | |
1217 | ||
e35d49f6 AV |
1218 | #ifdef CONFIG_COMPAT |
1219 | /* | |
1220 | * Exactly like sys_open(), except that it doesn't set the | |
1221 | * O_LARGEFILE flag. | |
1222 | */ | |
1223 | COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode) | |
1224 | { | |
1225 | return do_sys_open(AT_FDCWD, filename, flags, mode); | |
1226 | } | |
1227 | ||
1228 | /* | |
1229 | * Exactly like sys_openat(), except that it doesn't set the | |
1230 | * O_LARGEFILE flag. | |
1231 | */ | |
1232 | COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode) | |
1233 | { | |
1234 | return do_sys_open(dfd, filename, flags, mode); | |
1235 | } | |
1236 | #endif | |
1237 | ||
1da177e4 LT |
1238 | #ifndef __alpha__ |
1239 | ||
1240 | /* | |
1241 | * For backward compatibility? Maybe this should be moved | |
1242 | * into arch/i386 instead? | |
1243 | */ | |
a218d0fd | 1244 | SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode) |
1da177e4 | 1245 | { |
bae217ea | 1246 | return ksys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); |
1da177e4 LT |
1247 | } |
1248 | ||
1249 | #endif | |
1250 | ||
1251 | /* | |
1252 | * "id" is the POSIX thread ID. We use the | |
1253 | * files pointer for this.. | |
1254 | */ | |
1255 | int filp_close(struct file *filp, fl_owner_t id) | |
1256 | { | |
45778ca8 | 1257 | int retval = 0; |
1da177e4 LT |
1258 | |
1259 | if (!file_count(filp)) { | |
1260 | printk(KERN_ERR "VFS: Close: file count is 0\n"); | |
45778ca8 | 1261 | return 0; |
1da177e4 LT |
1262 | } |
1263 | ||
72c2d531 | 1264 | if (filp->f_op->flush) |
75e1fcc0 | 1265 | retval = filp->f_op->flush(filp, id); |
1da177e4 | 1266 | |
1abf0c71 AV |
1267 | if (likely(!(filp->f_mode & FMODE_PATH))) { |
1268 | dnotify_flush(filp, id); | |
1269 | locks_remove_posix(filp, id); | |
1270 | } | |
1da177e4 LT |
1271 | fput(filp); |
1272 | return retval; | |
1273 | } | |
1274 | ||
1275 | EXPORT_SYMBOL(filp_close); | |
1276 | ||
1277 | /* | |
1278 | * Careful here! We test whether the file pointer is NULL before | |
1279 | * releasing the fd. This ensures that one clone task can't release | |
1280 | * an fd while another clone is opening it. | |
1281 | */ | |
ca013e94 | 1282 | SYSCALL_DEFINE1(close, unsigned int, fd) |
1da177e4 | 1283 | { |
483ce1d4 | 1284 | int retval = __close_fd(current->files, fd); |
ee731f4f EP |
1285 | |
1286 | /* can't restart close syscall because file table entry was cleared */ | |
1287 | if (unlikely(retval == -ERESTARTSYS || | |
1288 | retval == -ERESTARTNOINTR || | |
1289 | retval == -ERESTARTNOHAND || | |
1290 | retval == -ERESTART_RESTARTBLOCK)) | |
1291 | retval = -EINTR; | |
1292 | ||
1293 | return retval; | |
1da177e4 | 1294 | } |
1da177e4 LT |
1295 | |
1296 | /* | |
1297 | * This routine simulates a hangup on the tty, to arrange that users | |
1298 | * are given clean terminals at login time. | |
1299 | */ | |
ca013e94 | 1300 | SYSCALL_DEFINE0(vhangup) |
1da177e4 LT |
1301 | { |
1302 | if (capable(CAP_SYS_TTY_CONFIG)) { | |
2cb5998b | 1303 | tty_vhangup_self(); |
1da177e4 LT |
1304 | return 0; |
1305 | } | |
1306 | return -EPERM; | |
1307 | } | |
1308 | ||
1309 | /* | |
1310 | * Called when an inode is about to be open. | |
1311 | * We use this to disallow opening large files on 32bit systems if | |
1312 | * the caller didn't specify O_LARGEFILE. On 64bit systems we force | |
1313 | * on this flag in sys_open. | |
1314 | */ | |
1315 | int generic_file_open(struct inode * inode, struct file * filp) | |
1316 | { | |
1317 | if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) | |
a9c62a18 | 1318 | return -EOVERFLOW; |
1da177e4 LT |
1319 | return 0; |
1320 | } | |
1321 | ||
1322 | EXPORT_SYMBOL(generic_file_open); | |
1323 | ||
1324 | /* | |
1325 | * This is used by subsystems that don't want seekable | |
06b1e104 DT |
1326 | * file descriptors. The function is not supposed to ever fail, the only |
1327 | * reason it returns an 'int' and not 'void' is so that it can be plugged | |
1328 | * directly into file_operations structure. | |
1da177e4 LT |
1329 | */ |
1330 | int nonseekable_open(struct inode *inode, struct file *filp) | |
1331 | { | |
1332 | filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); | |
1333 | return 0; | |
1334 | } | |
1335 | ||
1336 | EXPORT_SYMBOL(nonseekable_open); | |
10dce8af KS |
1337 | |
1338 | /* | |
1339 | * stream_open is used by subsystems that want stream-like file descriptors. | |
1340 | * Such file descriptors are not seekable and don't have notion of position | |
438ab720 KS |
1341 | * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL). |
1342 | * Contrary to file descriptors of other regular files, .read() and .write() | |
1343 | * can run simultaneously. | |
10dce8af KS |
1344 | * |
1345 | * stream_open never fails and is marked to return int so that it could be | |
1346 | * directly used as file_operations.open . | |
1347 | */ | |
1348 | int stream_open(struct inode *inode, struct file *filp) | |
1349 | { | |
2be7d348 | 1350 | filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS); |
10dce8af KS |
1351 | filp->f_mode |= FMODE_STREAM; |
1352 | return 0; | |
1353 | } | |
1354 | ||
1355 | EXPORT_SYMBOL(stream_open); |