1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/fs.h>
3 #include <linux/security.h>
4 #include <linux/fscrypt.h>
5 #include <linux/fileattr.h>
6 #include <linux/export.h>
7 #include <linux/syscalls.h>
8 #include <linux/namei.h>
9
10 #include "internal.h"
11
12 /**
13 * fileattr_fill_xflags - initialize fileattr with xflags
14 * @fa: fileattr pointer
15 * @xflags: FS_XFLAG_* flags
16 *
17 * Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags). All
18 * other fields are zeroed.
19 */
fileattr_fill_xflags(struct file_kattr * fa,u32 xflags)20 void fileattr_fill_xflags(struct file_kattr *fa, u32 xflags)
21 {
22 memset(fa, 0, sizeof(*fa));
23 fa->fsx_valid = true;
24 fa->fsx_xflags = xflags;
25 if (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)
26 fa->flags |= FS_IMMUTABLE_FL;
27 if (fa->fsx_xflags & FS_XFLAG_APPEND)
28 fa->flags |= FS_APPEND_FL;
29 if (fa->fsx_xflags & FS_XFLAG_SYNC)
30 fa->flags |= FS_SYNC_FL;
31 if (fa->fsx_xflags & FS_XFLAG_NOATIME)
32 fa->flags |= FS_NOATIME_FL;
33 if (fa->fsx_xflags & FS_XFLAG_NODUMP)
34 fa->flags |= FS_NODUMP_FL;
35 if (fa->fsx_xflags & FS_XFLAG_DAX)
36 fa->flags |= FS_DAX_FL;
37 if (fa->fsx_xflags & FS_XFLAG_PROJINHERIT)
38 fa->flags |= FS_PROJINHERIT_FL;
39 }
40 EXPORT_SYMBOL(fileattr_fill_xflags);
41
42 /**
43 * fileattr_fill_flags - initialize fileattr with flags
44 * @fa: fileattr pointer
45 * @flags: FS_*_FL flags
46 *
47 * Set ->flags, ->flags_valid and ->fsx_xflags (translated flags).
48 * All other fields are zeroed.
49 */
fileattr_fill_flags(struct file_kattr * fa,u32 flags)50 void fileattr_fill_flags(struct file_kattr *fa, u32 flags)
51 {
52 memset(fa, 0, sizeof(*fa));
53 fa->flags_valid = true;
54 fa->flags = flags;
55 if (fa->flags & FS_SYNC_FL)
56 fa->fsx_xflags |= FS_XFLAG_SYNC;
57 if (fa->flags & FS_IMMUTABLE_FL)
58 fa->fsx_xflags |= FS_XFLAG_IMMUTABLE;
59 if (fa->flags & FS_APPEND_FL)
60 fa->fsx_xflags |= FS_XFLAG_APPEND;
61 if (fa->flags & FS_NODUMP_FL)
62 fa->fsx_xflags |= FS_XFLAG_NODUMP;
63 if (fa->flags & FS_NOATIME_FL)
64 fa->fsx_xflags |= FS_XFLAG_NOATIME;
65 if (fa->flags & FS_DAX_FL)
66 fa->fsx_xflags |= FS_XFLAG_DAX;
67 if (fa->flags & FS_PROJINHERIT_FL)
68 fa->fsx_xflags |= FS_XFLAG_PROJINHERIT;
69 }
70 EXPORT_SYMBOL(fileattr_fill_flags);
71
72 /**
73 * vfs_fileattr_get - retrieve miscellaneous file attributes
74 * @dentry: the object to retrieve from
75 * @fa: fileattr pointer
76 *
77 * Call i_op->fileattr_get() callback, if exists.
78 *
79 * Return: 0 on success, or a negative error on failure.
80 */
vfs_fileattr_get(struct dentry * dentry,struct file_kattr * fa)81 int vfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
82 {
83 struct inode *inode = d_inode(dentry);
84 int error;
85
86 if (!inode->i_op->fileattr_get)
87 return -ENOIOCTLCMD;
88
89 error = security_inode_file_getattr(dentry, fa);
90 if (error)
91 return error;
92
93 return inode->i_op->fileattr_get(dentry, fa);
94 }
95 EXPORT_SYMBOL(vfs_fileattr_get);
96
fileattr_to_file_attr(const struct file_kattr * fa,struct file_attr * fattr)97 static void fileattr_to_file_attr(const struct file_kattr *fa,
98 struct file_attr *fattr)
99 {
100 __u32 mask = FS_XFLAGS_MASK;
101
102 memset(fattr, 0, sizeof(struct file_attr));
103 fattr->fa_xflags = fa->fsx_xflags & mask;
104 fattr->fa_extsize = fa->fsx_extsize;
105 fattr->fa_nextents = fa->fsx_nextents;
106 fattr->fa_projid = fa->fsx_projid;
107 fattr->fa_cowextsize = fa->fsx_cowextsize;
108 }
109
110 /**
111 * copy_fsxattr_to_user - copy fsxattr to userspace.
112 * @fa: fileattr pointer
113 * @ufa: fsxattr user pointer
114 *
115 * Return: 0 on success, or -EFAULT on failure.
116 */
copy_fsxattr_to_user(const struct file_kattr * fa,struct fsxattr __user * ufa)117 int copy_fsxattr_to_user(const struct file_kattr *fa, struct fsxattr __user *ufa)
118 {
119 struct fsxattr xfa;
120 __u32 mask = FS_XFLAGS_MASK;
121
122 memset(&xfa, 0, sizeof(xfa));
123 xfa.fsx_xflags = fa->fsx_xflags & mask;
124 xfa.fsx_extsize = fa->fsx_extsize;
125 xfa.fsx_nextents = fa->fsx_nextents;
126 xfa.fsx_projid = fa->fsx_projid;
127 xfa.fsx_cowextsize = fa->fsx_cowextsize;
128
129 if (copy_to_user(ufa, &xfa, sizeof(xfa)))
130 return -EFAULT;
131
132 return 0;
133 }
134 EXPORT_SYMBOL(copy_fsxattr_to_user);
135
file_attr_to_fileattr(const struct file_attr * fattr,struct file_kattr * fa)136 static int file_attr_to_fileattr(const struct file_attr *fattr,
137 struct file_kattr *fa)
138 {
139 __u64 mask = FS_XFLAGS_MASK;
140
141 if (fattr->fa_xflags & ~mask)
142 return -EINVAL;
143
144 fileattr_fill_xflags(fa, fattr->fa_xflags);
145 fa->fsx_xflags &= ~FS_XFLAG_RDONLY_MASK;
146 fa->fsx_extsize = fattr->fa_extsize;
147 fa->fsx_projid = fattr->fa_projid;
148 fa->fsx_cowextsize = fattr->fa_cowextsize;
149
150 return 0;
151 }
152
copy_fsxattr_from_user(struct file_kattr * fa,struct fsxattr __user * ufa)153 static int copy_fsxattr_from_user(struct file_kattr *fa,
154 struct fsxattr __user *ufa)
155 {
156 struct fsxattr xfa;
157 __u32 mask = FS_XFLAGS_MASK;
158
159 if (copy_from_user(&xfa, ufa, sizeof(xfa)))
160 return -EFAULT;
161
162 if (xfa.fsx_xflags & ~mask)
163 return -EOPNOTSUPP;
164
165 fileattr_fill_xflags(fa, xfa.fsx_xflags);
166 fa->fsx_xflags &= ~FS_XFLAG_RDONLY_MASK;
167 fa->fsx_extsize = xfa.fsx_extsize;
168 fa->fsx_nextents = xfa.fsx_nextents;
169 fa->fsx_projid = xfa.fsx_projid;
170 fa->fsx_cowextsize = xfa.fsx_cowextsize;
171
172 return 0;
173 }
174
175 /*
176 * Generic function to check FS_IOC_FSSETXATTR/FS_IOC_SETFLAGS values and reject
177 * any invalid configurations.
178 *
179 * Note: must be called with inode lock held.
180 */
fileattr_set_prepare(struct inode * inode,const struct file_kattr * old_ma,struct file_kattr * fa)181 static int fileattr_set_prepare(struct inode *inode,
182 const struct file_kattr *old_ma,
183 struct file_kattr *fa)
184 {
185 int err;
186
187 /*
188 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
189 * the relevant capability.
190 */
191 if ((fa->flags ^ old_ma->flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
192 !capable(CAP_LINUX_IMMUTABLE))
193 return -EPERM;
194
195 err = fscrypt_prepare_setflags(inode, old_ma->flags, fa->flags);
196 if (err)
197 return err;
198
199 /*
200 * Project Quota ID state is only allowed to change from within the init
201 * namespace. Enforce that restriction only if we are trying to change
202 * the quota ID state. Everything else is allowed in user namespaces.
203 */
204 if (current_user_ns() != &init_user_ns) {
205 if (old_ma->fsx_projid != fa->fsx_projid)
206 return -EINVAL;
207 if ((old_ma->fsx_xflags ^ fa->fsx_xflags) &
208 FS_XFLAG_PROJINHERIT)
209 return -EINVAL;
210 } else {
211 /*
212 * Caller is allowed to change the project ID. If it is being
213 * changed, make sure that the new value is valid.
214 */
215 if (old_ma->fsx_projid != fa->fsx_projid &&
216 !projid_valid(make_kprojid(&init_user_ns, fa->fsx_projid)))
217 return -EINVAL;
218 }
219
220 /* Check extent size hints. */
221 if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode))
222 return -EINVAL;
223
224 if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) &&
225 !S_ISDIR(inode->i_mode))
226 return -EINVAL;
227
228 if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) &&
229 !S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
230 return -EINVAL;
231
232 /*
233 * It is only valid to set the DAX flag on regular files and
234 * directories on filesystems.
235 */
236 if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
237 !(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
238 return -EINVAL;
239
240 /* Extent size hints of zero turn off the flags. */
241 if (fa->fsx_extsize == 0)
242 fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT);
243 if (fa->fsx_cowextsize == 0)
244 fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
245
246 return 0;
247 }
248
249 /**
250 * vfs_fileattr_set - change miscellaneous file attributes
251 * @idmap: idmap of the mount
252 * @dentry: the object to change
253 * @fa: fileattr pointer
254 *
255 * After verifying permissions, call i_op->fileattr_set() callback, if
256 * exists.
257 *
258 * Verifying attributes involves retrieving current attributes with
259 * i_op->fileattr_get(), this also allows initializing attributes that have
260 * not been set by the caller to current values. Inode lock is held
261 * thoughout to prevent racing with another instance.
262 *
263 * Return: 0 on success, or a negative error on failure.
264 */
vfs_fileattr_set(struct mnt_idmap * idmap,struct dentry * dentry,struct file_kattr * fa)265 int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry,
266 struct file_kattr *fa)
267 {
268 struct inode *inode = d_inode(dentry);
269 struct file_kattr old_ma = {};
270 int err;
271
272 if (!inode->i_op->fileattr_set)
273 return -ENOIOCTLCMD;
274
275 if (!inode_owner_or_capable(idmap, inode))
276 return -EPERM;
277
278 inode_lock(inode);
279 err = vfs_fileattr_get(dentry, &old_ma);
280 if (!err) {
281 /* initialize missing bits from old_ma */
282 if (fa->flags_valid) {
283 fa->fsx_xflags |= old_ma.fsx_xflags & ~FS_XFLAG_COMMON;
284 fa->fsx_extsize = old_ma.fsx_extsize;
285 fa->fsx_nextents = old_ma.fsx_nextents;
286 fa->fsx_projid = old_ma.fsx_projid;
287 fa->fsx_cowextsize = old_ma.fsx_cowextsize;
288 } else {
289 fa->flags |= old_ma.flags & ~FS_COMMON_FL;
290 }
291
292 err = fileattr_set_prepare(inode, &old_ma, fa);
293 if (err)
294 goto out;
295 err = security_inode_file_setattr(dentry, fa);
296 if (err)
297 goto out;
298 err = inode->i_op->fileattr_set(idmap, dentry, fa);
299 if (err)
300 goto out;
301 }
302
303 out:
304 inode_unlock(inode);
305 return err;
306 }
307 EXPORT_SYMBOL(vfs_fileattr_set);
308
ioctl_getflags(struct file * file,unsigned int __user * argp)309 int ioctl_getflags(struct file *file, unsigned int __user *argp)
310 {
311 struct file_kattr fa = { .flags_valid = true }; /* hint only */
312 int err;
313
314 err = vfs_fileattr_get(file->f_path.dentry, &fa);
315 if (!err)
316 err = put_user(fa.flags, argp);
317 return err;
318 }
319 EXPORT_SYMBOL(ioctl_getflags);
320
ioctl_setflags(struct file * file,unsigned int __user * argp)321 int ioctl_setflags(struct file *file, unsigned int __user *argp)
322 {
323 struct mnt_idmap *idmap = file_mnt_idmap(file);
324 struct dentry *dentry = file->f_path.dentry;
325 struct file_kattr fa;
326 unsigned int flags;
327 int err;
328
329 err = get_user(flags, argp);
330 if (!err) {
331 err = mnt_want_write_file(file);
332 if (!err) {
333 fileattr_fill_flags(&fa, flags);
334 err = vfs_fileattr_set(idmap, dentry, &fa);
335 mnt_drop_write_file(file);
336 }
337 }
338 return err;
339 }
340 EXPORT_SYMBOL(ioctl_setflags);
341
ioctl_fsgetxattr(struct file * file,void __user * argp)342 int ioctl_fsgetxattr(struct file *file, void __user *argp)
343 {
344 struct file_kattr fa = { .fsx_valid = true }; /* hint only */
345 int err;
346
347 err = vfs_fileattr_get(file->f_path.dentry, &fa);
348 if (!err)
349 err = copy_fsxattr_to_user(&fa, argp);
350
351 return err;
352 }
353 EXPORT_SYMBOL(ioctl_fsgetxattr);
354
ioctl_fssetxattr(struct file * file,void __user * argp)355 int ioctl_fssetxattr(struct file *file, void __user *argp)
356 {
357 struct mnt_idmap *idmap = file_mnt_idmap(file);
358 struct dentry *dentry = file->f_path.dentry;
359 struct file_kattr fa;
360 int err;
361
362 err = copy_fsxattr_from_user(&fa, argp);
363 if (!err) {
364 err = mnt_want_write_file(file);
365 if (!err) {
366 err = vfs_fileattr_set(idmap, dentry, &fa);
367 mnt_drop_write_file(file);
368 }
369 }
370 return err;
371 }
372 EXPORT_SYMBOL(ioctl_fssetxattr);
373
SYSCALL_DEFINE5(file_getattr,int,dfd,const char __user *,filename,struct file_attr __user *,ufattr,size_t,usize,unsigned int,at_flags)374 SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename,
375 struct file_attr __user *, ufattr, size_t, usize,
376 unsigned int, at_flags)
377 {
378 struct path filepath __free(path_put) = {};
379 struct filename *name __free(putname) = NULL;
380 unsigned int lookup_flags = 0;
381 struct file_attr fattr;
382 struct file_kattr fa;
383 int error;
384
385 BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0);
386 BUILD_BUG_ON(sizeof(struct file_attr) != FILE_ATTR_SIZE_LATEST);
387
388 if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
389 return -EINVAL;
390
391 if (!(at_flags & AT_SYMLINK_NOFOLLOW))
392 lookup_flags |= LOOKUP_FOLLOW;
393
394 if (usize > PAGE_SIZE)
395 return -E2BIG;
396
397 if (usize < FILE_ATTR_SIZE_VER0)
398 return -EINVAL;
399
400 name = getname_maybe_null(filename, at_flags);
401 if (IS_ERR(name))
402 return PTR_ERR(name);
403
404 if (!name && dfd >= 0) {
405 CLASS(fd, f)(dfd);
406 if (fd_empty(f))
407 return -EBADF;
408
409 filepath = fd_file(f)->f_path;
410 path_get(&filepath);
411 } else {
412 error = filename_lookup(dfd, name, lookup_flags, &filepath,
413 NULL);
414 if (error)
415 return error;
416 }
417
418 error = vfs_fileattr_get(filepath.dentry, &fa);
419 if (error == -ENOIOCTLCMD || error == -ENOTTY)
420 error = -EOPNOTSUPP;
421 if (error)
422 return error;
423
424 fileattr_to_file_attr(&fa, &fattr);
425 error = copy_struct_to_user(ufattr, usize, &fattr,
426 sizeof(struct file_attr), NULL);
427
428 return error;
429 }
430
SYSCALL_DEFINE5(file_setattr,int,dfd,const char __user *,filename,struct file_attr __user *,ufattr,size_t,usize,unsigned int,at_flags)431 SYSCALL_DEFINE5(file_setattr, int, dfd, const char __user *, filename,
432 struct file_attr __user *, ufattr, size_t, usize,
433 unsigned int, at_flags)
434 {
435 struct path filepath __free(path_put) = {};
436 struct filename *name __free(putname) = NULL;
437 unsigned int lookup_flags = 0;
438 struct file_attr fattr;
439 struct file_kattr fa;
440 int error;
441
442 BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0);
443 BUILD_BUG_ON(sizeof(struct file_attr) != FILE_ATTR_SIZE_LATEST);
444
445 if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
446 return -EINVAL;
447
448 if (!(at_flags & AT_SYMLINK_NOFOLLOW))
449 lookup_flags |= LOOKUP_FOLLOW;
450
451 if (usize > PAGE_SIZE)
452 return -E2BIG;
453
454 if (usize < FILE_ATTR_SIZE_VER0)
455 return -EINVAL;
456
457 error = copy_struct_from_user(&fattr, sizeof(struct file_attr), ufattr,
458 usize);
459 if (error)
460 return error;
461
462 error = file_attr_to_fileattr(&fattr, &fa);
463 if (error)
464 return error;
465
466 name = getname_maybe_null(filename, at_flags);
467 if (IS_ERR(name))
468 return PTR_ERR(name);
469
470 if (!name && dfd >= 0) {
471 CLASS(fd, f)(dfd);
472 if (fd_empty(f))
473 return -EBADF;
474
475 filepath = fd_file(f)->f_path;
476 path_get(&filepath);
477 } else {
478 error = filename_lookup(dfd, name, lookup_flags, &filepath,
479 NULL);
480 if (error)
481 return error;
482 }
483
484 error = mnt_want_write(filepath.mnt);
485 if (!error) {
486 error = vfs_fileattr_set(mnt_idmap(filepath.mnt),
487 filepath.dentry, &fa);
488 if (error == -ENOIOCTLCMD || error == -ENOTTY)
489 error = -EOPNOTSUPP;
490 mnt_drop_write(filepath.mnt);
491 }
492
493 return error;
494 }
495