]>
Commit | Line | Data |
---|---|---|
1c1ca807 | 1 | #include <linux/btrfs.h> |
45bd5d34 | 2 | #include <linux/capability.h> |
8bde1547 JB |
3 | #include <linux/cred.h> |
4 | #include <linux/mount.h> | |
1c1ca807 | 5 | #include <linux/fdtable.h> |
8bde1547 JB |
6 | #include <linux/file.h> |
7 | #include <linux/fs.h> | |
8 | #include <linux/namei.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/magic.h> | |
12 | #include <linux/parser.h> | |
45bd5d34 | 13 | #include <linux/security.h> |
8bde1547 JB |
14 | #include <linux/seq_file.h> |
15 | #include <linux/statfs.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/user_namespace.h> | |
18 | #include <linux/uidgid.h> | |
19 | #include <linux/xattr.h> | |
45bd5d34 CB |
20 | #include <linux/posix_acl.h> |
21 | #include <linux/posix_acl_xattr.h> | |
22 | #include <linux/uio.h> | |
60d66969 | 23 | #include <linux/fiemap.h> |
8bde1547 JB |
24 | |
25 | struct shiftfs_super_info { | |
26 | struct vfsmount *mnt; | |
27 | struct user_namespace *userns; | |
45bd5d34 CB |
28 | /* creds of process who created the super block */ |
29 | const struct cred *creator_cred; | |
8bde1547 | 30 | bool mark; |
45bd5d34 | 31 | unsigned int passthrough; |
d6d053b7 | 32 | unsigned int passthrough_mark; |
8bde1547 JB |
33 | }; |
34 | ||
45bd5d34 CB |
35 | static void shiftfs_fill_inode(struct inode *inode, unsigned long ino, |
36 | umode_t mode, dev_t dev, struct dentry *dentry); | |
37 | ||
38 | #define SHIFTFS_PASSTHROUGH_NONE 0 | |
39 | #define SHIFTFS_PASSTHROUGH_STAT 1 | |
1c1ca807 CB |
40 | #define SHIFTFS_PASSTHROUGH_IOCTL 2 |
41 | #define SHIFTFS_PASSTHROUGH_ALL \ | |
42 | (SHIFTFS_PASSTHROUGH_STAT | SHIFTFS_PASSTHROUGH_IOCTL) | |
43 | ||
44 | static inline bool shiftfs_passthrough_ioctls(struct shiftfs_super_info *info) | |
45 | { | |
46 | if (!(info->passthrough & SHIFTFS_PASSTHROUGH_IOCTL)) | |
47 | return false; | |
48 | ||
1c1ca807 CB |
49 | return true; |
50 | } | |
45bd5d34 CB |
51 | |
52 | static inline bool shiftfs_passthrough_statfs(struct shiftfs_super_info *info) | |
53 | { | |
54 | if (!(info->passthrough & SHIFTFS_PASSTHROUGH_STAT)) | |
55 | return false; | |
56 | ||
45bd5d34 CB |
57 | return true; |
58 | } | |
8bde1547 JB |
59 | |
60 | enum { | |
61 | OPT_MARK, | |
45bd5d34 | 62 | OPT_PASSTHROUGH, |
8bde1547 JB |
63 | OPT_LAST, |
64 | }; | |
65 | ||
66 | /* global filesystem options */ | |
67 | static const match_table_t tokens = { | |
68 | { OPT_MARK, "mark" }, | |
45bd5d34 | 69 | { OPT_PASSTHROUGH, "passthrough=%u" }, |
8bde1547 JB |
70 | { OPT_LAST, NULL } |
71 | }; | |
72 | ||
45bd5d34 | 73 | static const struct cred *shiftfs_override_creds(const struct super_block *sb) |
8bde1547 | 74 | { |
45bd5d34 | 75 | struct shiftfs_super_info *sbinfo = sb->s_fs_info; |
8bde1547 | 76 | |
45bd5d34 CB |
77 | return override_creds(sbinfo->creator_cred); |
78 | } | |
79 | ||
80 | static inline void shiftfs_revert_object_creds(const struct cred *oldcred, | |
81 | struct cred *newcred) | |
82 | { | |
83 | revert_creds(oldcred); | |
84 | put_cred(newcred); | |
85 | } | |
86 | ||
70aba758 SF |
87 | static kuid_t shift_kuid(struct user_namespace *from, struct user_namespace *to, |
88 | kuid_t kuid) | |
89 | { | |
90 | uid_t uid = from_kuid(from, kuid); | |
91 | return make_kuid(to, uid); | |
92 | } | |
93 | ||
94 | static kgid_t shift_kgid(struct user_namespace *from, struct user_namespace *to, | |
95 | kgid_t kgid) | |
96 | { | |
97 | gid_t gid = from_kgid(from, kgid); | |
98 | return make_kgid(to, gid); | |
99 | } | |
100 | ||
45bd5d34 CB |
101 | static int shiftfs_override_object_creds(const struct super_block *sb, |
102 | const struct cred **oldcred, | |
103 | struct cred **newcred, | |
104 | struct dentry *dentry, umode_t mode, | |
105 | bool hardlink) | |
106 | { | |
70aba758 | 107 | struct shiftfs_super_info *sbinfo = sb->s_fs_info; |
45bd5d34 CB |
108 | kuid_t fsuid = current_fsuid(); |
109 | kgid_t fsgid = current_fsgid(); | |
110 | ||
111 | *oldcred = shiftfs_override_creds(sb); | |
112 | ||
113 | *newcred = prepare_creds(); | |
114 | if (!*newcred) { | |
115 | revert_creds(*oldcred); | |
116 | return -ENOMEM; | |
117 | } | |
118 | ||
70aba758 SF |
119 | (*newcred)->fsuid = shift_kuid(sb->s_user_ns, sbinfo->userns, fsuid); |
120 | (*newcred)->fsgid = shift_kgid(sb->s_user_ns, sbinfo->userns, fsgid); | |
45bd5d34 CB |
121 | |
122 | if (!hardlink) { | |
123 | int err = security_dentry_create_files_as(dentry, mode, | |
124 | &dentry->d_name, | |
125 | *oldcred, *newcred); | |
126 | if (err) { | |
127 | shiftfs_revert_object_creds(*oldcred, *newcred); | |
128 | return err; | |
129 | } | |
130 | } | |
8bde1547 | 131 | |
45bd5d34 CB |
132 | put_cred(override_creds(*newcred)); |
133 | return 0; | |
134 | } | |
8bde1547 | 135 | |
45bd5d34 CB |
136 | static void shiftfs_copyattr(struct inode *from, struct inode *to) |
137 | { | |
138 | struct user_namespace *from_ns = from->i_sb->s_user_ns; | |
139 | struct user_namespace *to_ns = to->i_sb->s_user_ns; | |
140 | ||
141 | to->i_uid = shift_kuid(from_ns, to_ns, from->i_uid); | |
142 | to->i_gid = shift_kgid(from_ns, to_ns, from->i_gid); | |
143 | to->i_mode = from->i_mode; | |
144 | to->i_atime = from->i_atime; | |
145 | to->i_mtime = from->i_mtime; | |
146 | to->i_ctime = from->i_ctime; | |
147 | i_size_write(to, i_size_read(from)); | |
148 | } | |
8bde1547 | 149 | |
45bd5d34 CB |
150 | static void shiftfs_copyflags(struct inode *from, struct inode *to) |
151 | { | |
152 | unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME; | |
8bde1547 | 153 | |
45bd5d34 | 154 | inode_set_flags(to, from->i_flags & mask, mask); |
8bde1547 JB |
155 | } |
156 | ||
45bd5d34 | 157 | static void shiftfs_file_accessed(struct file *file) |
8bde1547 | 158 | { |
45bd5d34 CB |
159 | struct inode *upperi, *loweri; |
160 | ||
161 | if (file->f_flags & O_NOATIME) | |
8bde1547 JB |
162 | return; |
163 | ||
45bd5d34 CB |
164 | upperi = file_inode(file); |
165 | loweri = upperi->i_private; | |
166 | ||
167 | if (!loweri) | |
168 | return; | |
169 | ||
170 | upperi->i_mtime = loweri->i_mtime; | |
171 | upperi->i_ctime = loweri->i_ctime; | |
172 | ||
173 | touch_atime(&file->f_path); | |
8bde1547 JB |
174 | } |
175 | ||
45bd5d34 CB |
176 | static int shiftfs_parse_mount_options(struct shiftfs_super_info *sbinfo, |
177 | char *options) | |
8bde1547 JB |
178 | { |
179 | char *p; | |
180 | substring_t args[MAX_OPT_ARGS]; | |
181 | ||
45bd5d34 CB |
182 | sbinfo->mark = false; |
183 | sbinfo->passthrough = 0; | |
8bde1547 JB |
184 | |
185 | while ((p = strsep(&options, ",")) != NULL) { | |
45bd5d34 | 186 | int err, intarg, token; |
8bde1547 JB |
187 | |
188 | if (!*p) | |
189 | continue; | |
190 | ||
191 | token = match_token(p, tokens, args); | |
192 | switch (token) { | |
193 | case OPT_MARK: | |
45bd5d34 CB |
194 | sbinfo->mark = true; |
195 | break; | |
196 | case OPT_PASSTHROUGH: | |
197 | err = match_int(&args[0], &intarg); | |
198 | if (err) | |
199 | return err; | |
200 | ||
201 | if (intarg & ~SHIFTFS_PASSTHROUGH_ALL) | |
202 | return -EINVAL; | |
203 | ||
204 | sbinfo->passthrough = intarg; | |
8bde1547 JB |
205 | break; |
206 | default: | |
207 | return -EINVAL; | |
208 | } | |
209 | } | |
45bd5d34 | 210 | |
8bde1547 JB |
211 | return 0; |
212 | } | |
213 | ||
214 | static void shiftfs_d_release(struct dentry *dentry) | |
215 | { | |
45bd5d34 | 216 | struct dentry *lowerd = dentry->d_fsdata; |
8bde1547 | 217 | |
45bd5d34 CB |
218 | if (lowerd) |
219 | dput(lowerd); | |
8bde1547 JB |
220 | } |
221 | ||
222 | static struct dentry *shiftfs_d_real(struct dentry *dentry, | |
223 | const struct inode *inode) | |
224 | { | |
45bd5d34 CB |
225 | struct dentry *lowerd = dentry->d_fsdata; |
226 | ||
227 | if (inode && d_inode(dentry) == inode) | |
228 | return dentry; | |
8bde1547 | 229 | |
45bd5d34 CB |
230 | lowerd = d_real(lowerd, inode); |
231 | if (lowerd && (!inode || inode == d_inode(lowerd))) | |
232 | return lowerd; | |
8bde1547 | 233 | |
45bd5d34 CB |
234 | WARN(1, "shiftfs_d_real(%pd4, %s:%lu): real dentry not found\n", dentry, |
235 | inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); | |
236 | return dentry; | |
8bde1547 JB |
237 | } |
238 | ||
239 | static int shiftfs_d_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
240 | { | |
45bd5d34 CB |
241 | int err = 1; |
242 | struct dentry *lowerd = dentry->d_fsdata; | |
8bde1547 | 243 | |
45bd5d34 | 244 | if (d_is_negative(lowerd) != d_is_negative(dentry)) |
8bde1547 JB |
245 | return 0; |
246 | ||
45bd5d34 CB |
247 | if ((lowerd->d_flags & DCACHE_OP_WEAK_REVALIDATE)) |
248 | err = lowerd->d_op->d_weak_revalidate(lowerd, flags); | |
8bde1547 | 249 | |
45bd5d34 CB |
250 | if (d_really_is_positive(dentry)) { |
251 | struct inode *inode = d_inode(dentry); | |
252 | struct inode *loweri = d_inode(lowerd); | |
253 | ||
254 | shiftfs_copyattr(loweri, inode); | |
45bd5d34 CB |
255 | } |
256 | ||
257 | return err; | |
8bde1547 JB |
258 | } |
259 | ||
260 | static int shiftfs_d_revalidate(struct dentry *dentry, unsigned int flags) | |
261 | { | |
45bd5d34 CB |
262 | int err = 1; |
263 | struct dentry *lowerd = dentry->d_fsdata; | |
8bde1547 | 264 | |
45bd5d34 CB |
265 | if (d_unhashed(lowerd) || |
266 | ((d_is_negative(lowerd) != d_is_negative(dentry)))) | |
8bde1547 JB |
267 | return 0; |
268 | ||
45bd5d34 CB |
269 | if (flags & LOOKUP_RCU) |
270 | return -ECHILD; | |
8bde1547 | 271 | |
45bd5d34 CB |
272 | if ((lowerd->d_flags & DCACHE_OP_REVALIDATE)) |
273 | err = lowerd->d_op->d_revalidate(lowerd, flags); | |
8bde1547 | 274 | |
45bd5d34 CB |
275 | if (d_really_is_positive(dentry)) { |
276 | struct inode *inode = d_inode(dentry); | |
277 | struct inode *loweri = d_inode(lowerd); | |
8bde1547 | 278 | |
45bd5d34 | 279 | shiftfs_copyattr(loweri, inode); |
45bd5d34 | 280 | } |
8bde1547 | 281 | |
45bd5d34 | 282 | return err; |
8bde1547 JB |
283 | } |
284 | ||
285 | static const struct dentry_operations shiftfs_dentry_ops = { | |
45bd5d34 CB |
286 | .d_release = shiftfs_d_release, |
287 | .d_real = shiftfs_d_real, | |
288 | .d_revalidate = shiftfs_d_revalidate, | |
8bde1547 JB |
289 | .d_weak_revalidate = shiftfs_d_weak_revalidate, |
290 | }; | |
291 | ||
8bde1547 JB |
292 | static const char *shiftfs_get_link(struct dentry *dentry, struct inode *inode, |
293 | struct delayed_call *done) | |
294 | { | |
45bd5d34 CB |
295 | const char *p; |
296 | const struct cred *oldcred; | |
297 | struct dentry *lowerd; | |
8bde1547 | 298 | |
45bd5d34 CB |
299 | /* RCU lookup not supported */ |
300 | if (!dentry) | |
8bde1547 | 301 | return ERR_PTR(-ECHILD); |
45bd5d34 CB |
302 | |
303 | lowerd = dentry->d_fsdata; | |
304 | oldcred = shiftfs_override_creds(dentry->d_sb); | |
305 | p = vfs_get_link(lowerd, done); | |
306 | revert_creds(oldcred); | |
307 | ||
308 | return p; | |
8bde1547 JB |
309 | } |
310 | ||
311 | static int shiftfs_setxattr(struct dentry *dentry, struct inode *inode, | |
312 | const char *name, const void *value, | |
313 | size_t size, int flags) | |
314 | { | |
45bd5d34 CB |
315 | struct dentry *lowerd = dentry->d_fsdata; |
316 | int err; | |
317 | const struct cred *oldcred; | |
318 | ||
319 | oldcred = shiftfs_override_creds(dentry->d_sb); | |
320 | err = vfs_setxattr(lowerd, name, value, size, flags); | |
321 | revert_creds(oldcred); | |
8bde1547 | 322 | |
45bd5d34 | 323 | shiftfs_copyattr(lowerd->d_inode, inode); |
8bde1547 JB |
324 | |
325 | return err; | |
326 | } | |
327 | ||
328 | static int shiftfs_xattr_get(const struct xattr_handler *handler, | |
329 | struct dentry *dentry, struct inode *inode, | |
330 | const char *name, void *value, size_t size) | |
331 | { | |
45bd5d34 | 332 | struct dentry *lowerd = dentry->d_fsdata; |
8bde1547 | 333 | int err; |
45bd5d34 | 334 | const struct cred *oldcred; |
8bde1547 | 335 | |
45bd5d34 CB |
336 | oldcred = shiftfs_override_creds(dentry->d_sb); |
337 | err = vfs_getxattr(lowerd, name, value, size); | |
338 | revert_creds(oldcred); | |
8bde1547 JB |
339 | |
340 | return err; | |
341 | } | |
342 | ||
343 | static ssize_t shiftfs_listxattr(struct dentry *dentry, char *list, | |
344 | size_t size) | |
345 | { | |
45bd5d34 | 346 | struct dentry *lowerd = dentry->d_fsdata; |
8bde1547 | 347 | int err; |
45bd5d34 | 348 | const struct cred *oldcred; |
8bde1547 | 349 | |
45bd5d34 CB |
350 | oldcred = shiftfs_override_creds(dentry->d_sb); |
351 | err = vfs_listxattr(lowerd, list, size); | |
352 | revert_creds(oldcred); | |
8bde1547 JB |
353 | |
354 | return err; | |
355 | } | |
356 | ||
357 | static int shiftfs_removexattr(struct dentry *dentry, const char *name) | |
358 | { | |
45bd5d34 | 359 | struct dentry *lowerd = dentry->d_fsdata; |
8bde1547 | 360 | int err; |
45bd5d34 CB |
361 | const struct cred *oldcred; |
362 | ||
363 | oldcred = shiftfs_override_creds(dentry->d_sb); | |
364 | err = vfs_removexattr(lowerd, name); | |
365 | revert_creds(oldcred); | |
8bde1547 | 366 | |
45bd5d34 CB |
367 | /* update c/mtime */ |
368 | shiftfs_copyattr(lowerd->d_inode, d_inode(dentry)); | |
8bde1547 JB |
369 | |
370 | return err; | |
371 | } | |
372 | ||
373 | static int shiftfs_xattr_set(const struct xattr_handler *handler, | |
374 | struct dentry *dentry, struct inode *inode, | |
375 | const char *name, const void *value, size_t size, | |
376 | int flags) | |
377 | { | |
378 | if (!value) | |
379 | return shiftfs_removexattr(dentry, name); | |
380 | return shiftfs_setxattr(dentry, inode, name, value, size, flags); | |
381 | } | |
382 | ||
45bd5d34 | 383 | static int shiftfs_inode_test(struct inode *inode, void *data) |
8bde1547 | 384 | { |
45bd5d34 CB |
385 | return inode->i_private == data; |
386 | } | |
8bde1547 | 387 | |
45bd5d34 CB |
388 | static int shiftfs_inode_set(struct inode *inode, void *data) |
389 | { | |
390 | inode->i_private = data; | |
391 | return 0; | |
8bde1547 JB |
392 | } |
393 | ||
45bd5d34 CB |
394 | static int shiftfs_create_object(struct inode *diri, struct dentry *dentry, |
395 | umode_t mode, const char *symlink, | |
396 | struct dentry *hardlink, bool excl) | |
8bde1547 | 397 | { |
8bde1547 | 398 | int err; |
45bd5d34 CB |
399 | const struct cred *oldcred; |
400 | struct cred *newcred; | |
401 | void *loweri_iop_ptr = NULL; | |
402 | umode_t modei = mode; | |
403 | struct super_block *dir_sb = diri->i_sb; | |
404 | struct dentry *lowerd_new = dentry->d_fsdata; | |
405 | struct inode *inode = NULL, *loweri_dir = diri->i_private; | |
406 | const struct inode_operations *loweri_dir_iop = loweri_dir->i_op; | |
407 | struct dentry *lowerd_link = NULL; | |
8bde1547 JB |
408 | |
409 | if (hardlink) { | |
45bd5d34 | 410 | loweri_iop_ptr = loweri_dir_iop->link; |
8bde1547 JB |
411 | } else { |
412 | switch (mode & S_IFMT) { | |
413 | case S_IFDIR: | |
45bd5d34 | 414 | loweri_iop_ptr = loweri_dir_iop->mkdir; |
8bde1547 JB |
415 | break; |
416 | case S_IFREG: | |
45bd5d34 | 417 | loweri_iop_ptr = loweri_dir_iop->create; |
8bde1547 JB |
418 | break; |
419 | case S_IFLNK: | |
45bd5d34 CB |
420 | loweri_iop_ptr = loweri_dir_iop->symlink; |
421 | break; | |
422 | case S_IFSOCK: | |
423 | /* fall through */ | |
424 | case S_IFIFO: | |
425 | loweri_iop_ptr = loweri_dir_iop->mknod; | |
426 | break; | |
8bde1547 JB |
427 | } |
428 | } | |
45bd5d34 CB |
429 | if (!loweri_iop_ptr) { |
430 | err = -EINVAL; | |
431 | goto out_iput; | |
432 | } | |
8bde1547 | 433 | |
45bd5d34 | 434 | inode_lock_nested(loweri_dir, I_MUTEX_PARENT); |
8bde1547 | 435 | |
45bd5d34 CB |
436 | if (!hardlink) { |
437 | inode = new_inode(dir_sb); | |
438 | if (!inode) { | |
439 | err = -ENOMEM; | |
440 | goto out_iput; | |
441 | } | |
442 | ||
443 | /* | |
444 | * new_inode() will have added the new inode to the super | |
445 | * block's list of inodes. Further below we will call | |
446 | * inode_insert5() Which would perform the same operation again | |
447 | * thereby corrupting the list. To avoid this raise I_CREATING | |
448 | * in i_state which will cause inode_insert5() to skip this | |
449 | * step. I_CREATING will be cleared by d_instantiate_new() | |
450 | * below. | |
451 | */ | |
452 | spin_lock(&inode->i_lock); | |
453 | inode->i_state |= I_CREATING; | |
454 | spin_unlock(&inode->i_lock); | |
8bde1547 | 455 | |
45bd5d34 CB |
456 | inode_init_owner(inode, diri, mode); |
457 | modei = inode->i_mode; | |
458 | } | |
8bde1547 | 459 | |
45bd5d34 CB |
460 | err = shiftfs_override_object_creds(dentry->d_sb, &oldcred, &newcred, |
461 | dentry, modei, hardlink != NULL); | |
462 | if (err) | |
463 | goto out_iput; | |
8bde1547 | 464 | |
8bde1547 | 465 | if (hardlink) { |
45bd5d34 CB |
466 | lowerd_link = hardlink->d_fsdata; |
467 | err = vfs_link(lowerd_link, loweri_dir, lowerd_new, NULL); | |
8bde1547 | 468 | } else { |
45bd5d34 | 469 | switch (modei & S_IFMT) { |
8bde1547 | 470 | case S_IFDIR: |
45bd5d34 | 471 | err = vfs_mkdir(loweri_dir, lowerd_new, modei); |
8bde1547 JB |
472 | break; |
473 | case S_IFREG: | |
45bd5d34 | 474 | err = vfs_create(loweri_dir, lowerd_new, modei, excl); |
8bde1547 JB |
475 | break; |
476 | case S_IFLNK: | |
45bd5d34 CB |
477 | err = vfs_symlink(loweri_dir, lowerd_new, symlink); |
478 | break; | |
479 | case S_IFSOCK: | |
480 | /* fall through */ | |
481 | case S_IFIFO: | |
482 | err = vfs_mknod(loweri_dir, lowerd_new, modei, 0); | |
483 | break; | |
484 | default: | |
485 | err = -EINVAL; | |
486 | break; | |
8bde1547 JB |
487 | } |
488 | } | |
489 | ||
45bd5d34 | 490 | shiftfs_revert_object_creds(oldcred, newcred); |
8bde1547 | 491 | |
45bd5d34 CB |
492 | if (!err && WARN_ON(!lowerd_new->d_inode)) |
493 | err = -EIO; | |
8bde1547 | 494 | if (err) |
45bd5d34 CB |
495 | goto out_iput; |
496 | ||
497 | if (hardlink) { | |
498 | inode = d_inode(hardlink); | |
499 | ihold(inode); | |
500 | ||
501 | /* copy up times from lower inode */ | |
502 | shiftfs_copyattr(d_inode(lowerd_link), inode); | |
503 | set_nlink(d_inode(hardlink), d_inode(lowerd_link)->i_nlink); | |
504 | d_instantiate(dentry, inode); | |
505 | } else { | |
506 | struct inode *inode_tmp; | |
507 | struct inode *loweri_new = d_inode(lowerd_new); | |
508 | ||
509 | inode_tmp = inode_insert5(inode, (unsigned long)loweri_new, | |
510 | shiftfs_inode_test, shiftfs_inode_set, | |
511 | loweri_new); | |
512 | if (unlikely(inode_tmp != inode)) { | |
513 | pr_err_ratelimited("shiftfs: newly created inode found in cache\n"); | |
514 | iput(inode_tmp); | |
515 | err = -EINVAL; | |
516 | goto out_iput; | |
517 | } | |
8bde1547 | 518 | |
45bd5d34 CB |
519 | ihold(loweri_new); |
520 | shiftfs_fill_inode(inode, loweri_new->i_ino, loweri_new->i_mode, | |
521 | 0, lowerd_new); | |
522 | d_instantiate_new(dentry, inode); | |
523 | } | |
8bde1547 | 524 | |
45bd5d34 CB |
525 | shiftfs_copyattr(loweri_dir, diri); |
526 | if (loweri_iop_ptr == loweri_dir_iop->mkdir) | |
527 | set_nlink(diri, loweri_dir->i_nlink); | |
8bde1547 | 528 | |
45bd5d34 | 529 | inode = NULL; |
8bde1547 | 530 | |
45bd5d34 CB |
531 | out_iput: |
532 | iput(inode); | |
533 | inode_unlock(loweri_dir); | |
8bde1547 JB |
534 | |
535 | return err; | |
536 | } | |
537 | ||
538 | static int shiftfs_create(struct inode *dir, struct dentry *dentry, | |
539 | umode_t mode, bool excl) | |
540 | { | |
541 | mode |= S_IFREG; | |
542 | ||
45bd5d34 | 543 | return shiftfs_create_object(dir, dentry, mode, NULL, NULL, excl); |
8bde1547 JB |
544 | } |
545 | ||
546 | static int shiftfs_mkdir(struct inode *dir, struct dentry *dentry, | |
547 | umode_t mode) | |
548 | { | |
549 | mode |= S_IFDIR; | |
550 | ||
45bd5d34 | 551 | return shiftfs_create_object(dir, dentry, mode, NULL, NULL, false); |
8bde1547 JB |
552 | } |
553 | ||
554 | static int shiftfs_link(struct dentry *hardlink, struct inode *dir, | |
555 | struct dentry *dentry) | |
556 | { | |
45bd5d34 CB |
557 | return shiftfs_create_object(dir, dentry, 0, NULL, hardlink, false); |
558 | } | |
559 | ||
560 | static int shiftfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
561 | dev_t rdev) | |
562 | { | |
563 | if (!S_ISFIFO(mode) && !S_ISSOCK(mode)) | |
564 | return -EPERM; | |
565 | ||
566 | return shiftfs_create_object(dir, dentry, mode, NULL, NULL, false); | |
8bde1547 JB |
567 | } |
568 | ||
569 | static int shiftfs_symlink(struct inode *dir, struct dentry *dentry, | |
570 | const char *symlink) | |
571 | { | |
45bd5d34 | 572 | return shiftfs_create_object(dir, dentry, S_IFLNK, symlink, NULL, false); |
8bde1547 JB |
573 | } |
574 | ||
575 | static int shiftfs_rm(struct inode *dir, struct dentry *dentry, bool rmdir) | |
576 | { | |
45bd5d34 CB |
577 | struct dentry *lowerd = dentry->d_fsdata; |
578 | struct inode *loweri = dir->i_private; | |
0161f2e5 | 579 | struct inode *inode = d_inode(dentry); |
8bde1547 | 580 | int err; |
45bd5d34 | 581 | const struct cred *oldcred; |
8bde1547 | 582 | |
28017416 | 583 | dget(lowerd); |
45bd5d34 CB |
584 | oldcred = shiftfs_override_creds(dentry->d_sb); |
585 | inode_lock_nested(loweri, I_MUTEX_PARENT); | |
8bde1547 | 586 | if (rmdir) |
45bd5d34 | 587 | err = vfs_rmdir(loweri, lowerd); |
8bde1547 | 588 | else |
45bd5d34 | 589 | err = vfs_unlink(loweri, lowerd, NULL); |
45bd5d34 | 590 | revert_creds(oldcred); |
8bde1547 | 591 | |
0161f2e5 | 592 | if (!err) { |
45bd5d34 CB |
593 | d_drop(dentry); |
594 | ||
0161f2e5 CB |
595 | if (rmdir) |
596 | clear_nlink(inode); | |
597 | else | |
598 | drop_nlink(inode); | |
599 | } | |
600 | inode_unlock(loweri); | |
601 | ||
602 | shiftfs_copyattr(loweri, dir); | |
28017416 | 603 | dput(lowerd); |
8bde1547 JB |
604 | |
605 | return err; | |
606 | } | |
607 | ||
608 | static int shiftfs_unlink(struct inode *dir, struct dentry *dentry) | |
609 | { | |
610 | return shiftfs_rm(dir, dentry, false); | |
611 | } | |
612 | ||
613 | static int shiftfs_rmdir(struct inode *dir, struct dentry *dentry) | |
614 | { | |
615 | return shiftfs_rm(dir, dentry, true); | |
616 | } | |
617 | ||
618 | static int shiftfs_rename(struct inode *olddir, struct dentry *old, | |
619 | struct inode *newdir, struct dentry *new, | |
620 | unsigned int flags) | |
621 | { | |
45bd5d34 CB |
622 | struct dentry *lowerd_dir_old = old->d_parent->d_fsdata, |
623 | *lowerd_dir_new = new->d_parent->d_fsdata, | |
624 | *lowerd_old = old->d_fsdata, *lowerd_new = new->d_fsdata, | |
625 | *trapd; | |
626 | struct inode *loweri_dir_old = lowerd_dir_old->d_inode, | |
627 | *loweri_dir_new = lowerd_dir_new->d_inode; | |
8bde1547 | 628 | int err = -EINVAL; |
45bd5d34 | 629 | const struct cred *oldcred; |
8bde1547 | 630 | |
45bd5d34 | 631 | trapd = lock_rename(lowerd_dir_new, lowerd_dir_old); |
8bde1547 | 632 | |
45bd5d34 | 633 | if (trapd == lowerd_old || trapd == lowerd_new) |
8bde1547 JB |
634 | goto out_unlock; |
635 | ||
45bd5d34 CB |
636 | oldcred = shiftfs_override_creds(old->d_sb); |
637 | err = vfs_rename(loweri_dir_old, lowerd_old, loweri_dir_new, lowerd_new, | |
638 | NULL, flags); | |
639 | revert_creds(oldcred); | |
8bde1547 | 640 | |
45bd5d34 CB |
641 | shiftfs_copyattr(loweri_dir_old, olddir); |
642 | shiftfs_copyattr(loweri_dir_new, newdir); | |
8bde1547 | 643 | |
45bd5d34 CB |
644 | out_unlock: |
645 | unlock_rename(lowerd_dir_new, lowerd_dir_old); | |
8bde1547 JB |
646 | |
647 | return err; | |
648 | } | |
649 | ||
650 | static struct dentry *shiftfs_lookup(struct inode *dir, struct dentry *dentry, | |
651 | unsigned int flags) | |
652 | { | |
45bd5d34 CB |
653 | struct dentry *new; |
654 | struct inode *newi; | |
655 | const struct cred *oldcred; | |
656 | struct dentry *lowerd = dentry->d_parent->d_fsdata; | |
657 | struct inode *inode = NULL, *loweri = lowerd->d_inode; | |
658 | ||
659 | inode_lock(loweri); | |
660 | oldcred = shiftfs_override_creds(dentry->d_sb); | |
661 | new = lookup_one_len(dentry->d_name.name, lowerd, dentry->d_name.len); | |
662 | revert_creds(oldcred); | |
663 | inode_unlock(loweri); | |
8bde1547 JB |
664 | |
665 | if (IS_ERR(new)) | |
666 | return new; | |
667 | ||
668 | dentry->d_fsdata = new; | |
669 | ||
45bd5d34 CB |
670 | newi = new->d_inode; |
671 | if (!newi) | |
8bde1547 JB |
672 | goto out; |
673 | ||
45bd5d34 CB |
674 | inode = iget5_locked(dentry->d_sb, (unsigned long)newi, |
675 | shiftfs_inode_test, shiftfs_inode_set, newi); | |
676 | if (!inode) { | |
8bde1547 JB |
677 | dput(new); |
678 | return ERR_PTR(-ENOMEM); | |
679 | } | |
45bd5d34 CB |
680 | if (inode->i_state & I_NEW) { |
681 | /* | |
682 | * inode->i_private set by shiftfs_inode_set(), but we still | |
683 | * need to take a reference | |
684 | */ | |
685 | ihold(newi); | |
686 | shiftfs_fill_inode(inode, newi->i_ino, newi->i_mode, 0, new); | |
687 | unlock_new_inode(inode); | |
688 | } | |
8bde1547 | 689 | |
45bd5d34 CB |
690 | out: |
691 | return d_splice_alias(inode, dentry); | |
8bde1547 JB |
692 | } |
693 | ||
694 | static int shiftfs_permission(struct inode *inode, int mask) | |
695 | { | |
8bde1547 | 696 | int err; |
45bd5d34 CB |
697 | const struct cred *oldcred; |
698 | struct inode *loweri = inode->i_private; | |
8bde1547 | 699 | |
45bd5d34 CB |
700 | if (!loweri) { |
701 | WARN_ON(!(mask & MAY_NOT_BLOCK)); | |
8bde1547 | 702 | return -ECHILD; |
45bd5d34 | 703 | } |
8bde1547 | 704 | |
45bd5d34 CB |
705 | err = generic_permission(inode, mask); |
706 | if (err) | |
707 | return err; | |
708 | ||
709 | oldcred = shiftfs_override_creds(inode->i_sb); | |
710 | err = inode_permission(loweri, mask); | |
711 | revert_creds(oldcred); | |
712 | ||
713 | return err; | |
714 | } | |
715 | ||
716 | static int shiftfs_fiemap(struct inode *inode, | |
717 | struct fiemap_extent_info *fieinfo, u64 start, | |
718 | u64 len) | |
719 | { | |
720 | int err; | |
721 | const struct cred *oldcred; | |
722 | struct inode *loweri = inode->i_private; | |
723 | ||
724 | if (!loweri->i_op->fiemap) | |
725 | return -EOPNOTSUPP; | |
726 | ||
727 | oldcred = shiftfs_override_creds(inode->i_sb); | |
728 | if (fieinfo->fi_flags & FIEMAP_FLAG_SYNC) | |
729 | filemap_write_and_wait(loweri->i_mapping); | |
730 | err = loweri->i_op->fiemap(loweri, fieinfo, start, len); | |
731 | revert_creds(oldcred); | |
732 | ||
733 | return err; | |
734 | } | |
735 | ||
736 | static int shiftfs_tmpfile(struct inode *dir, struct dentry *dentry, | |
737 | umode_t mode) | |
738 | { | |
739 | int err; | |
740 | const struct cred *oldcred; | |
741 | struct dentry *lowerd = dentry->d_fsdata; | |
742 | struct inode *loweri = dir->i_private; | |
743 | ||
744 | if (!loweri->i_op->tmpfile) | |
745 | return -EOPNOTSUPP; | |
746 | ||
747 | oldcred = shiftfs_override_creds(dir->i_sb); | |
748 | err = loweri->i_op->tmpfile(loweri, lowerd, mode); | |
749 | revert_creds(oldcred); | |
8bde1547 JB |
750 | |
751 | return err; | |
752 | } | |
753 | ||
754 | static int shiftfs_setattr(struct dentry *dentry, struct iattr *attr) | |
755 | { | |
45bd5d34 CB |
756 | struct dentry *lowerd = dentry->d_fsdata; |
757 | struct inode *loweri = lowerd->d_inode; | |
8feb2474 | 758 | struct iattr newattr; |
45bd5d34 | 759 | const struct cred *oldcred; |
8bde1547 | 760 | struct super_block *sb = dentry->d_sb; |
70aba758 | 761 | struct shiftfs_super_info *sbinfo = sb->s_fs_info; |
8bde1547 JB |
762 | int err; |
763 | ||
45bd5d34 CB |
764 | err = setattr_prepare(dentry, attr); |
765 | if (err) | |
766 | return err; | |
767 | ||
8feb2474 | 768 | newattr = *attr; |
70aba758 SF |
769 | newattr.ia_uid = shift_kuid(sb->s_user_ns, sbinfo->userns, attr->ia_uid); |
770 | newattr.ia_gid = shift_kgid(sb->s_user_ns, sbinfo->userns, attr->ia_gid); | |
8bde1547 | 771 | |
8feb2474 SF |
772 | /* |
773 | * mode change is for clearing setuid/setgid bits. Allow lower fs | |
774 | * to interpret this in its own way. | |
775 | */ | |
776 | if (newattr.ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) | |
777 | newattr.ia_valid &= ~ATTR_MODE; | |
778 | ||
45bd5d34 CB |
779 | inode_lock(loweri); |
780 | oldcred = shiftfs_override_creds(dentry->d_sb); | |
ce4b8676 | 781 | err = notify_change(lowerd, &newattr, NULL); |
45bd5d34 CB |
782 | revert_creds(oldcred); |
783 | inode_unlock(loweri); | |
8bde1547 | 784 | |
45bd5d34 | 785 | shiftfs_copyattr(loweri, d_inode(dentry)); |
8bde1547 | 786 | |
45bd5d34 | 787 | return err; |
8bde1547 JB |
788 | } |
789 | ||
790 | static int shiftfs_getattr(const struct path *path, struct kstat *stat, | |
791 | u32 request_mask, unsigned int query_flags) | |
792 | { | |
793 | struct inode *inode = path->dentry->d_inode; | |
45bd5d34 CB |
794 | struct dentry *lowerd = path->dentry->d_fsdata; |
795 | struct inode *loweri = lowerd->d_inode; | |
796 | struct shiftfs_super_info *info = path->dentry->d_sb->s_fs_info; | |
797 | struct path newpath = { .mnt = info->mnt, .dentry = lowerd }; | |
798 | struct user_namespace *from_ns = loweri->i_sb->s_user_ns; | |
799 | struct user_namespace *to_ns = inode->i_sb->s_user_ns; | |
800 | const struct cred *oldcred; | |
801 | int err; | |
802 | ||
803 | oldcred = shiftfs_override_creds(inode->i_sb); | |
804 | err = vfs_getattr(&newpath, stat, request_mask, query_flags); | |
805 | revert_creds(oldcred); | |
8bde1547 JB |
806 | |
807 | if (err) | |
808 | return err; | |
809 | ||
810 | /* transform the underlying id */ | |
45bd5d34 CB |
811 | stat->uid = shift_kuid(from_ns, to_ns, stat->uid); |
812 | stat->gid = shift_kgid(from_ns, to_ns, stat->gid); | |
8bde1547 JB |
813 | return 0; |
814 | } | |
815 | ||
45bd5d34 | 816 | #ifdef CONFIG_SHIFT_FS_POSIX_ACL |
8bde1547 | 817 | |
45bd5d34 CB |
818 | static int |
819 | shift_acl_ids(struct user_namespace *from, struct user_namespace *to, | |
820 | struct posix_acl *acl) | |
8bde1547 | 821 | { |
45bd5d34 CB |
822 | int i; |
823 | ||
824 | for (i = 0; i < acl->a_count; i++) { | |
825 | struct posix_acl_entry *e = &acl->a_entries[i]; | |
826 | switch(e->e_tag) { | |
827 | case ACL_USER: | |
828 | e->e_uid = shift_kuid(from, to, e->e_uid); | |
829 | if (!uid_valid(e->e_uid)) | |
830 | return -EOVERFLOW; | |
831 | break; | |
832 | case ACL_GROUP: | |
833 | e->e_gid = shift_kgid(from, to, e->e_gid); | |
834 | if (!gid_valid(e->e_gid)) | |
835 | return -EOVERFLOW; | |
836 | break; | |
837 | } | |
838 | } | |
839 | return 0; | |
840 | } | |
8bde1547 | 841 | |
45bd5d34 CB |
842 | static void |
843 | shift_acl_xattr_ids(struct user_namespace *from, struct user_namespace *to, | |
844 | void *value, size_t size) | |
845 | { | |
846 | struct posix_acl_xattr_header *header = value; | |
847 | struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end; | |
848 | int count; | |
849 | kuid_t kuid; | |
850 | kgid_t kgid; | |
8bde1547 | 851 | |
45bd5d34 CB |
852 | if (!value) |
853 | return; | |
854 | if (size < sizeof(struct posix_acl_xattr_header)) | |
855 | return; | |
856 | if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) | |
857 | return; | |
8bde1547 | 858 | |
45bd5d34 CB |
859 | count = posix_acl_xattr_count(size); |
860 | if (count < 0) | |
861 | return; | |
862 | if (count == 0) | |
863 | return; | |
8bde1547 | 864 | |
45bd5d34 CB |
865 | for (end = entry + count; entry != end; entry++) { |
866 | switch(le16_to_cpu(entry->e_tag)) { | |
867 | case ACL_USER: | |
868 | kuid = make_kuid(&init_user_ns, le32_to_cpu(entry->e_id)); | |
869 | kuid = shift_kuid(from, to, kuid); | |
870 | entry->e_id = cpu_to_le32(from_kuid(&init_user_ns, kuid)); | |
871 | break; | |
872 | case ACL_GROUP: | |
873 | kgid = make_kgid(&init_user_ns, le32_to_cpu(entry->e_id)); | |
874 | kgid = shift_kgid(from, to, kgid); | |
875 | entry->e_id = cpu_to_le32(from_kgid(&init_user_ns, kgid)); | |
876 | break; | |
877 | default: | |
878 | break; | |
879 | } | |
880 | } | |
8bde1547 JB |
881 | } |
882 | ||
45bd5d34 | 883 | static struct posix_acl *shiftfs_get_acl(struct inode *inode, int type) |
8bde1547 | 884 | { |
45bd5d34 CB |
885 | struct inode *loweri = inode->i_private; |
886 | const struct cred *oldcred; | |
887 | struct posix_acl *lower_acl, *acl = NULL; | |
888 | struct user_namespace *from_ns = loweri->i_sb->s_user_ns; | |
889 | struct user_namespace *to_ns = inode->i_sb->s_user_ns; | |
890 | int size; | |
891 | int err; | |
8bde1547 | 892 | |
45bd5d34 CB |
893 | if (!IS_POSIXACL(loweri)) |
894 | return NULL; | |
8bde1547 | 895 | |
45bd5d34 CB |
896 | oldcred = shiftfs_override_creds(inode->i_sb); |
897 | lower_acl = get_acl(loweri, type); | |
898 | revert_creds(oldcred); | |
8bde1547 | 899 | |
45bd5d34 CB |
900 | if (lower_acl && !IS_ERR(lower_acl)) { |
901 | /* XXX: export posix_acl_clone? */ | |
902 | size = sizeof(struct posix_acl) + | |
903 | lower_acl->a_count * sizeof(struct posix_acl_entry); | |
904 | acl = kmemdup(lower_acl, size, GFP_KERNEL); | |
905 | posix_acl_release(lower_acl); | |
8bde1547 | 906 | |
45bd5d34 CB |
907 | if (!acl) |
908 | return ERR_PTR(-ENOMEM); | |
8bde1547 | 909 | |
45bd5d34 | 910 | refcount_set(&acl->a_refcount, 1); |
8bde1547 | 911 | |
45bd5d34 CB |
912 | err = shift_acl_ids(from_ns, to_ns, acl); |
913 | if (err) { | |
914 | kfree(acl); | |
915 | return ERR_PTR(err); | |
916 | } | |
917 | } | |
918 | ||
919 | return acl; | |
8bde1547 JB |
920 | } |
921 | ||
45bd5d34 CB |
922 | static int |
923 | shiftfs_posix_acl_xattr_get(const struct xattr_handler *handler, | |
924 | struct dentry *dentry, struct inode *inode, | |
925 | const char *name, void *buffer, size_t size) | |
8bde1547 | 926 | { |
45bd5d34 CB |
927 | struct inode *loweri = inode->i_private; |
928 | int ret; | |
929 | ||
930 | ret = shiftfs_xattr_get(NULL, dentry, inode, handler->name, | |
931 | buffer, size); | |
932 | if (ret < 0) | |
933 | return ret; | |
8bde1547 | 934 | |
45bd5d34 CB |
935 | inode_lock(loweri); |
936 | shift_acl_xattr_ids(loweri->i_sb->s_user_ns, inode->i_sb->s_user_ns, | |
937 | buffer, size); | |
938 | inode_unlock(loweri); | |
939 | return ret; | |
8bde1547 JB |
940 | } |
941 | ||
45bd5d34 CB |
942 | static int |
943 | shiftfs_posix_acl_xattr_set(const struct xattr_handler *handler, | |
944 | struct dentry *dentry, struct inode *inode, | |
945 | const char *name, const void *value, | |
946 | size_t size, int flags) | |
947 | { | |
948 | struct inode *loweri = inode->i_private; | |
949 | int err; | |
8bde1547 | 950 | |
45bd5d34 CB |
951 | if (!IS_POSIXACL(loweri) || !loweri->i_op->set_acl) |
952 | return -EOPNOTSUPP; | |
953 | if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) | |
954 | return value ? -EACCES : 0; | |
955 | if (!inode_owner_or_capable(inode)) | |
956 | return -EPERM; | |
957 | ||
958 | if (value) { | |
959 | shift_acl_xattr_ids(inode->i_sb->s_user_ns, | |
960 | loweri->i_sb->s_user_ns, | |
961 | (void *)value, size); | |
962 | err = shiftfs_setxattr(dentry, inode, handler->name, value, | |
963 | size, flags); | |
964 | } else { | |
965 | err = shiftfs_removexattr(dentry, handler->name); | |
966 | } | |
8bde1547 | 967 | |
45bd5d34 CB |
968 | if (!err) |
969 | shiftfs_copyattr(loweri, inode); | |
970 | ||
971 | return err; | |
972 | } | |
973 | ||
974 | static const struct xattr_handler | |
975 | shiftfs_posix_acl_access_xattr_handler = { | |
976 | .name = XATTR_NAME_POSIX_ACL_ACCESS, | |
977 | .flags = ACL_TYPE_ACCESS, | |
978 | .get = shiftfs_posix_acl_xattr_get, | |
979 | .set = shiftfs_posix_acl_xattr_set, | |
8bde1547 JB |
980 | }; |
981 | ||
45bd5d34 CB |
982 | static const struct xattr_handler |
983 | shiftfs_posix_acl_default_xattr_handler = { | |
984 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, | |
985 | .flags = ACL_TYPE_DEFAULT, | |
986 | .get = shiftfs_posix_acl_xattr_get, | |
987 | .set = shiftfs_posix_acl_xattr_set, | |
8bde1547 JB |
988 | }; |
989 | ||
45bd5d34 | 990 | #else /* !CONFIG_SHIFT_FS_POSIX_ACL */ |
8bde1547 | 991 | |
45bd5d34 | 992 | #define shiftfs_get_acl NULL |
8bde1547 | 993 | |
45bd5d34 | 994 | #endif /* CONFIG_SHIFT_FS_POSIX_ACL */ |
8bde1547 | 995 | |
45bd5d34 CB |
996 | static const struct inode_operations shiftfs_dir_inode_operations = { |
997 | .lookup = shiftfs_lookup, | |
998 | .mkdir = shiftfs_mkdir, | |
999 | .symlink = shiftfs_symlink, | |
1000 | .unlink = shiftfs_unlink, | |
1001 | .rmdir = shiftfs_rmdir, | |
1002 | .rename = shiftfs_rename, | |
1003 | .link = shiftfs_link, | |
1004 | .setattr = shiftfs_setattr, | |
1005 | .create = shiftfs_create, | |
1006 | .mknod = shiftfs_mknod, | |
1007 | .permission = shiftfs_permission, | |
1008 | .getattr = shiftfs_getattr, | |
1009 | .listxattr = shiftfs_listxattr, | |
1010 | .get_acl = shiftfs_get_acl, | |
1011 | }; | |
1012 | ||
1013 | static const struct inode_operations shiftfs_file_inode_operations = { | |
1014 | .fiemap = shiftfs_fiemap, | |
1015 | .getattr = shiftfs_getattr, | |
1016 | .get_acl = shiftfs_get_acl, | |
1017 | .listxattr = shiftfs_listxattr, | |
1018 | .permission = shiftfs_permission, | |
1019 | .setattr = shiftfs_setattr, | |
1020 | .tmpfile = shiftfs_tmpfile, | |
1021 | }; | |
1022 | ||
1023 | static const struct inode_operations shiftfs_special_inode_operations = { | |
1024 | .getattr = shiftfs_getattr, | |
1025 | .get_acl = shiftfs_get_acl, | |
1026 | .listxattr = shiftfs_listxattr, | |
1027 | .permission = shiftfs_permission, | |
1028 | .setattr = shiftfs_setattr, | |
1029 | }; | |
1030 | ||
1031 | static const struct inode_operations shiftfs_symlink_inode_operations = { | |
1032 | .getattr = shiftfs_getattr, | |
1033 | .get_link = shiftfs_get_link, | |
1034 | .listxattr = shiftfs_listxattr, | |
1035 | .setattr = shiftfs_setattr, | |
1036 | }; | |
1037 | ||
1038 | static struct file *shiftfs_open_realfile(const struct file *file, | |
159ec080 | 1039 | struct inode *realinode) |
45bd5d34 | 1040 | { |
159ec080 CB |
1041 | struct file *realfile; |
1042 | const struct cred *old_cred; | |
45bd5d34 | 1043 | struct inode *inode = file_inode(file); |
159ec080 | 1044 | struct dentry *lowerd = file->f_path.dentry->d_fsdata; |
45bd5d34 | 1045 | struct shiftfs_super_info *info = inode->i_sb->s_fs_info; |
159ec080 | 1046 | struct path realpath = { .mnt = info->mnt, .dentry = lowerd }; |
45bd5d34 | 1047 | |
159ec080 CB |
1048 | old_cred = shiftfs_override_creds(inode->i_sb); |
1049 | realfile = open_with_fake_path(&realpath, file->f_flags, realinode, | |
1050 | info->creator_cred); | |
1051 | revert_creds(old_cred); | |
45bd5d34 | 1052 | |
159ec080 | 1053 | return realfile; |
45bd5d34 CB |
1054 | } |
1055 | ||
1056 | #define SHIFTFS_SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT) | |
1057 | ||
1058 | static int shiftfs_change_flags(struct file *file, unsigned int flags) | |
1059 | { | |
1060 | struct inode *inode = file_inode(file); | |
1061 | int err; | |
1062 | ||
1063 | /* if some flag changed that cannot be changed then something's amiss */ | |
1064 | if (WARN_ON((file->f_flags ^ flags) & ~SHIFTFS_SETFL_MASK)) | |
1065 | return -EIO; | |
1066 | ||
1067 | flags &= SHIFTFS_SETFL_MASK; | |
1068 | ||
1069 | if (((flags ^ file->f_flags) & O_APPEND) && IS_APPEND(inode)) | |
1070 | return -EPERM; | |
1071 | ||
1072 | if (flags & O_DIRECT) { | |
1073 | if (!file->f_mapping->a_ops || | |
1074 | !file->f_mapping->a_ops->direct_IO) | |
1075 | return -EINVAL; | |
1076 | } | |
1077 | ||
1078 | if (file->f_op->check_flags) { | |
1079 | err = file->f_op->check_flags(flags); | |
1080 | if (err) | |
1081 | return err; | |
1082 | } | |
1083 | ||
1084 | spin_lock(&file->f_lock); | |
1085 | file->f_flags = (file->f_flags & ~SHIFTFS_SETFL_MASK) | flags; | |
1086 | spin_unlock(&file->f_lock); | |
1087 | ||
1088 | return 0; | |
1089 | } | |
1090 | ||
45bd5d34 CB |
1091 | static int shiftfs_open(struct inode *inode, struct file *file) |
1092 | { | |
45bd5d34 | 1093 | struct file *realfile; |
45bd5d34 | 1094 | |
159ec080 CB |
1095 | realfile = shiftfs_open_realfile(file, inode->i_private); |
1096 | if (IS_ERR(realfile)) | |
45bd5d34 | 1097 | return PTR_ERR(realfile); |
45bd5d34 | 1098 | |
159ec080 | 1099 | file->private_data = realfile; |
2813574e CB |
1100 | /* For O_DIRECT dentry_open() checks f_mapping->a_ops->direct_IO. */ |
1101 | file->f_mapping = realfile->f_mapping; | |
1102 | ||
45bd5d34 CB |
1103 | return 0; |
1104 | } | |
1105 | ||
159ec080 | 1106 | static int shiftfs_dir_open(struct inode *inode, struct file *file) |
45bd5d34 | 1107 | { |
159ec080 CB |
1108 | struct file *realfile; |
1109 | const struct cred *oldcred; | |
1110 | struct dentry *lowerd = file->f_path.dentry->d_fsdata; | |
1111 | struct shiftfs_super_info *info = inode->i_sb->s_fs_info; | |
1112 | struct path realpath = { .mnt = info->mnt, .dentry = lowerd }; | |
1113 | ||
1114 | oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb); | |
1115 | realfile = dentry_open(&realpath, file->f_flags | O_NOATIME, | |
1116 | info->creator_cred); | |
1117 | revert_creds(oldcred); | |
1118 | if (IS_ERR(realfile)) | |
1119 | return PTR_ERR(realfile); | |
45bd5d34 | 1120 | |
159ec080 | 1121 | file->private_data = realfile; |
45bd5d34 | 1122 | |
159ec080 CB |
1123 | return 0; |
1124 | } | |
1125 | ||
1126 | static int shiftfs_release(struct inode *inode, struct file *file) | |
1127 | { | |
1128 | struct file *realfile = file->private_data; | |
1129 | ||
1130 | if (realfile) | |
1131 | fput(realfile); | |
45bd5d34 CB |
1132 | |
1133 | return 0; | |
1134 | } | |
1135 | ||
159ec080 CB |
1136 | static int shiftfs_dir_release(struct inode *inode, struct file *file) |
1137 | { | |
1138 | return shiftfs_release(inode, file); | |
1139 | } | |
1140 | ||
f3365a72 CB |
1141 | static loff_t shiftfs_dir_llseek(struct file *file, loff_t offset, int whence) |
1142 | { | |
159ec080 | 1143 | struct file *realfile = file->private_data; |
f3365a72 CB |
1144 | |
1145 | return vfs_llseek(realfile, offset, whence); | |
1146 | } | |
1147 | ||
1148 | static loff_t shiftfs_file_llseek(struct file *file, loff_t offset, int whence) | |
45bd5d34 CB |
1149 | { |
1150 | struct inode *realinode = file_inode(file)->i_private; | |
1151 | ||
1152 | return generic_file_llseek_size(file, offset, whence, | |
1153 | realinode->i_sb->s_maxbytes, | |
1154 | i_size_read(realinode)); | |
1155 | } | |
1156 | ||
1157 | /* XXX: Need to figure out what to to about atime updates, maybe other | |
1158 | * timestamps too ... ref. ovl_file_accessed() */ | |
1159 | ||
1160 | static rwf_t shiftfs_iocb_to_rwf(struct kiocb *iocb) | |
1161 | { | |
1162 | int ifl = iocb->ki_flags; | |
1163 | rwf_t flags = 0; | |
1164 | ||
1165 | if (ifl & IOCB_NOWAIT) | |
1166 | flags |= RWF_NOWAIT; | |
1167 | if (ifl & IOCB_HIPRI) | |
1168 | flags |= RWF_HIPRI; | |
1169 | if (ifl & IOCB_DSYNC) | |
1170 | flags |= RWF_DSYNC; | |
1171 | if (ifl & IOCB_SYNC) | |
1172 | flags |= RWF_SYNC; | |
1173 | ||
1174 | return flags; | |
1175 | } | |
1176 | ||
294b3b78 CB |
1177 | static int shiftfs_real_fdget(const struct file *file, struct fd *lowerfd) |
1178 | { | |
1179 | struct file *realfile; | |
1180 | ||
1181 | if (file->f_op->open != shiftfs_open && | |
1182 | file->f_op->open != shiftfs_dir_open) | |
1183 | return -EINVAL; | |
1184 | ||
1185 | realfile = file->private_data; | |
1186 | lowerfd->flags = 0; | |
1187 | lowerfd->file = realfile; | |
1188 | ||
1189 | /* Did the flags change since open? */ | |
1190 | if (unlikely(file->f_flags & ~lowerfd->file->f_flags)) | |
1191 | return shiftfs_change_flags(lowerfd->file, file->f_flags); | |
1192 | ||
1193 | return 0; | |
1194 | } | |
1195 | ||
45bd5d34 CB |
1196 | static ssize_t shiftfs_read_iter(struct kiocb *iocb, struct iov_iter *iter) |
1197 | { | |
1198 | struct file *file = iocb->ki_filp; | |
1199 | struct fd lowerfd; | |
1200 | const struct cred *oldcred; | |
1201 | ssize_t ret; | |
1202 | ||
1203 | if (!iov_iter_count(iter)) | |
1204 | return 0; | |
1205 | ||
1206 | ret = shiftfs_real_fdget(file, &lowerfd); | |
1207 | if (ret) | |
1208 | return ret; | |
1209 | ||
1210 | oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb); | |
1211 | ret = vfs_iter_read(lowerfd.file, iter, &iocb->ki_pos, | |
1212 | shiftfs_iocb_to_rwf(iocb)); | |
1213 | revert_creds(oldcred); | |
1214 | ||
1215 | shiftfs_file_accessed(file); | |
1216 | ||
1217 | fdput(lowerfd); | |
1218 | return ret; | |
1219 | } | |
1220 | ||
1221 | static ssize_t shiftfs_write_iter(struct kiocb *iocb, struct iov_iter *iter) | |
1222 | { | |
1223 | struct file *file = iocb->ki_filp; | |
1224 | struct inode *inode = file_inode(file); | |
1225 | struct fd lowerfd; | |
1226 | const struct cred *oldcred; | |
1227 | ssize_t ret; | |
1228 | ||
1229 | if (!iov_iter_count(iter)) | |
1230 | return 0; | |
1231 | ||
1232 | inode_lock(inode); | |
1233 | /* Update mode */ | |
1234 | shiftfs_copyattr(inode->i_private, inode); | |
1235 | ret = file_remove_privs(file); | |
1236 | if (ret) | |
1237 | goto out_unlock; | |
1238 | ||
1239 | ret = shiftfs_real_fdget(file, &lowerfd); | |
1240 | if (ret) | |
1241 | goto out_unlock; | |
1242 | ||
1243 | oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb); | |
1244 | file_start_write(lowerfd.file); | |
1245 | ret = vfs_iter_write(lowerfd.file, iter, &iocb->ki_pos, | |
1246 | shiftfs_iocb_to_rwf(iocb)); | |
1247 | file_end_write(lowerfd.file); | |
1248 | revert_creds(oldcred); | |
1249 | ||
1250 | /* Update size */ | |
1251 | shiftfs_copyattr(inode->i_private, inode); | |
1252 | ||
1253 | fdput(lowerfd); | |
1254 | ||
1255 | out_unlock: | |
1256 | inode_unlock(inode); | |
1257 | return ret; | |
1258 | } | |
1259 | ||
1260 | static int shiftfs_fsync(struct file *file, loff_t start, loff_t end, | |
1261 | int datasync) | |
1262 | { | |
1263 | struct fd lowerfd; | |
1264 | const struct cred *oldcred; | |
1265 | int ret; | |
1266 | ||
1267 | ret = shiftfs_real_fdget(file, &lowerfd); | |
1268 | if (ret) | |
1269 | return ret; | |
1270 | ||
1271 | oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb); | |
1272 | ret = vfs_fsync_range(lowerfd.file, start, end, datasync); | |
1273 | revert_creds(oldcred); | |
1274 | ||
1275 | fdput(lowerfd); | |
1276 | return ret; | |
1277 | } | |
1278 | ||
1279 | static int shiftfs_mmap(struct file *file, struct vm_area_struct *vma) | |
1280 | { | |
159ec080 | 1281 | struct file *realfile = file->private_data; |
45bd5d34 CB |
1282 | const struct cred *oldcred; |
1283 | int ret; | |
1284 | ||
1285 | if (!realfile->f_op->mmap) | |
1286 | return -ENODEV; | |
1287 | ||
1288 | if (WARN_ON(file != vma->vm_file)) | |
1289 | return -EIO; | |
1290 | ||
1291 | oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb); | |
1292 | vma->vm_file = get_file(realfile); | |
1293 | ret = call_mmap(vma->vm_file, vma); | |
1294 | revert_creds(oldcred); | |
1295 | ||
1296 | shiftfs_file_accessed(file); | |
1297 | ||
4341d573 SF |
1298 | if (ret) { |
1299 | /* | |
1300 | * Drop refcount from new vm_file value and restore original | |
1301 | * vm_file value | |
1302 | */ | |
1303 | vma->vm_file = file; | |
1304 | fput(realfile); | |
1305 | } else { | |
1306 | /* Drop refcount from previous vm_file value */ | |
1307 | fput(file); | |
1308 | } | |
45bd5d34 CB |
1309 | |
1310 | return ret; | |
1311 | } | |
1312 | ||
1313 | static long shiftfs_fallocate(struct file *file, int mode, loff_t offset, | |
1314 | loff_t len) | |
1315 | { | |
1316 | struct inode *inode = file_inode(file); | |
1317 | struct inode *loweri = inode->i_private; | |
1318 | struct fd lowerfd; | |
1319 | const struct cred *oldcred; | |
1320 | int ret; | |
1321 | ||
1322 | ret = shiftfs_real_fdget(file, &lowerfd); | |
1323 | if (ret) | |
1324 | return ret; | |
1325 | ||
1326 | oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb); | |
1327 | ret = vfs_fallocate(lowerfd.file, mode, offset, len); | |
1328 | revert_creds(oldcred); | |
1329 | ||
1330 | /* Update size */ | |
1331 | shiftfs_copyattr(loweri, inode); | |
1332 | ||
1333 | fdput(lowerfd); | |
1334 | return ret; | |
1335 | } | |
1336 | ||
1337 | static int shiftfs_fadvise(struct file *file, loff_t offset, loff_t len, | |
1338 | int advice) | |
1339 | { | |
1340 | struct fd lowerfd; | |
1341 | const struct cred *oldcred; | |
1342 | int ret; | |
1343 | ||
1344 | ret = shiftfs_real_fdget(file, &lowerfd); | |
1345 | if (ret) | |
1346 | return ret; | |
1347 | ||
1348 | oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb); | |
1349 | ret = vfs_fadvise(lowerfd.file, offset, len, advice); | |
1350 | revert_creds(oldcred); | |
1351 | ||
1352 | fdput(lowerfd); | |
1353 | return ret; | |
1354 | } | |
1355 | ||
f91b73d4 | 1356 | static int shiftfs_override_ioctl_creds(int cmd, const struct super_block *sb, |
45bd5d34 CB |
1357 | const struct cred **oldcred, |
1358 | struct cred **newcred) | |
1359 | { | |
70aba758 | 1360 | struct shiftfs_super_info *sbinfo = sb->s_fs_info; |
45bd5d34 CB |
1361 | kuid_t fsuid = current_fsuid(); |
1362 | kgid_t fsgid = current_fsgid(); | |
1363 | ||
1364 | *oldcred = shiftfs_override_creds(sb); | |
1365 | ||
1366 | *newcred = prepare_creds(); | |
1367 | if (!*newcred) { | |
1368 | revert_creds(*oldcred); | |
1369 | return -ENOMEM; | |
1370 | } | |
1371 | ||
70aba758 SF |
1372 | (*newcred)->fsuid = shift_kuid(sb->s_user_ns, sbinfo->userns, fsuid); |
1373 | (*newcred)->fsgid = shift_kgid(sb->s_user_ns, sbinfo->userns, fsgid); | |
45bd5d34 CB |
1374 | |
1375 | /* clear all caps to prevent bypassing capable() checks */ | |
1376 | cap_clear((*newcred)->cap_bset); | |
1377 | cap_clear((*newcred)->cap_effective); | |
1378 | cap_clear((*newcred)->cap_inheritable); | |
1379 | cap_clear((*newcred)->cap_permitted); | |
1380 | ||
f91b73d4 CB |
1381 | if (cmd == BTRFS_IOC_SNAP_DESTROY) { |
1382 | kuid_t kuid_root = make_kuid(sb->s_user_ns, 0); | |
1383 | /* | |
1384 | * Allow the root user in the container to remove subvolumes | |
1385 | * from other users. | |
1386 | */ | |
1387 | if (uid_valid(kuid_root) && uid_eq(fsuid, kuid_root)) | |
1388 | cap_raise((*newcred)->cap_effective, CAP_DAC_OVERRIDE); | |
1389 | } | |
1390 | ||
45bd5d34 CB |
1391 | put_cred(override_creds(*newcred)); |
1392 | return 0; | |
1393 | } | |
1394 | ||
1395 | static inline void shiftfs_revert_ioctl_creds(const struct cred *oldcred, | |
1396 | struct cred *newcred) | |
1397 | { | |
1398 | return shiftfs_revert_object_creds(oldcred, newcred); | |
1399 | } | |
1400 | ||
1c1ca807 CB |
1401 | static inline bool is_btrfs_snap_ioctl(int cmd) |
1402 | { | |
1403 | if ((cmd == BTRFS_IOC_SNAP_CREATE) || (cmd == BTRFS_IOC_SNAP_CREATE_V2)) | |
1404 | return true; | |
1405 | ||
1406 | return false; | |
1407 | } | |
1408 | ||
f7e373a5 | 1409 | static int shiftfs_btrfs_ioctl_fd_restore(int cmd, int fd, void __user *arg, |
1c1ca807 CB |
1410 | struct btrfs_ioctl_vol_args *v1, |
1411 | struct btrfs_ioctl_vol_args_v2 *v2) | |
1412 | { | |
1413 | int ret; | |
1414 | ||
1415 | if (!is_btrfs_snap_ioctl(cmd)) | |
1416 | return 0; | |
1417 | ||
1418 | if (cmd == BTRFS_IOC_SNAP_CREATE) | |
1419 | ret = copy_to_user(arg, v1, sizeof(*v1)); | |
1420 | else | |
1421 | ret = copy_to_user(arg, v2, sizeof(*v2)); | |
1422 | ||
c6843acc | 1423 | close_fd(fd); |
1c1ca807 CB |
1424 | kfree(v1); |
1425 | kfree(v2); | |
1426 | ||
e11c9078 | 1427 | return ret ? -EFAULT: 0; |
1c1ca807 CB |
1428 | } |
1429 | ||
1430 | static int shiftfs_btrfs_ioctl_fd_replace(int cmd, void __user *arg, | |
1431 | struct btrfs_ioctl_vol_args **b1, | |
1432 | struct btrfs_ioctl_vol_args_v2 **b2, | |
1c1ca807 CB |
1433 | int *newfd) |
1434 | { | |
1435 | int oldfd, ret; | |
1436 | struct fd src; | |
f7e373a5 | 1437 | struct fd lfd = {}; |
1c1ca807 CB |
1438 | struct btrfs_ioctl_vol_args *v1 = NULL; |
1439 | struct btrfs_ioctl_vol_args_v2 *v2 = NULL; | |
1440 | ||
eb00293d SF |
1441 | *b1 = NULL; |
1442 | *b2 = NULL; | |
1443 | ||
1c1ca807 CB |
1444 | if (!is_btrfs_snap_ioctl(cmd)) |
1445 | return 0; | |
1446 | ||
1447 | if (cmd == BTRFS_IOC_SNAP_CREATE) { | |
1448 | v1 = memdup_user(arg, sizeof(*v1)); | |
1449 | if (IS_ERR(v1)) | |
1450 | return PTR_ERR(v1); | |
1451 | oldfd = v1->fd; | |
1c1ca807 CB |
1452 | } else { |
1453 | v2 = memdup_user(arg, sizeof(*v2)); | |
1454 | if (IS_ERR(v2)) | |
1455 | return PTR_ERR(v2); | |
1456 | oldfd = v2->fd; | |
1c1ca807 CB |
1457 | } |
1458 | ||
1459 | src = fdget(oldfd); | |
eb00293d SF |
1460 | if (!src.file) { |
1461 | ret = -EINVAL; | |
1462 | goto err_free; | |
1463 | } | |
1c1ca807 | 1464 | |
f7e373a5 SF |
1465 | ret = shiftfs_real_fdget(src.file, &lfd); |
1466 | if (ret) { | |
1467 | fdput(src); | |
eb00293d | 1468 | goto err_free; |
f7e373a5 SF |
1469 | } |
1470 | ||
1471 | /* | |
1472 | * shiftfs_real_fdget() does not take a reference to lfd.file, so | |
1473 | * take a reference here to offset the one which will be put by | |
c6843acc | 1474 | * close_fd(), and make sure that reference is put on fdput(lfd). |
f7e373a5 SF |
1475 | */ |
1476 | get_file(lfd.file); | |
1477 | lfd.flags |= FDPUT_FPUT; | |
1478 | fdput(src); | |
1c1ca807 | 1479 | |
f7e373a5 | 1480 | *newfd = get_unused_fd_flags(lfd.file->f_flags); |
1c1ca807 | 1481 | if (*newfd < 0) { |
f7e373a5 | 1482 | fdput(lfd); |
eb00293d SF |
1483 | ret = *newfd; |
1484 | goto err_free; | |
1c1ca807 CB |
1485 | } |
1486 | ||
f7e373a5 | 1487 | fd_install(*newfd, lfd.file); |
1c1ca807 CB |
1488 | |
1489 | if (cmd == BTRFS_IOC_SNAP_CREATE) { | |
1490 | v1->fd = *newfd; | |
1491 | ret = copy_to_user(arg, v1, sizeof(*v1)); | |
1492 | v1->fd = oldfd; | |
1493 | } else { | |
1494 | v2->fd = *newfd; | |
1495 | ret = copy_to_user(arg, v2, sizeof(*v2)); | |
1496 | v2->fd = oldfd; | |
1497 | } | |
1498 | ||
eb00293d SF |
1499 | if (!ret) { |
1500 | *b1 = v1; | |
1501 | *b2 = v2; | |
1502 | } else { | |
f7e373a5 | 1503 | shiftfs_btrfs_ioctl_fd_restore(cmd, *newfd, arg, v1, v2); |
e11c9078 | 1504 | ret = -EFAULT; |
eb00293d SF |
1505 | } |
1506 | ||
1507 | return ret; | |
1508 | ||
1509 | err_free: | |
1510 | kfree(v1); | |
1511 | kfree(v2); | |
1c1ca807 CB |
1512 | |
1513 | return ret; | |
1514 | } | |
1515 | ||
45bd5d34 CB |
1516 | static long shiftfs_real_ioctl(struct file *file, unsigned int cmd, |
1517 | unsigned long arg) | |
1518 | { | |
45bd5d34 CB |
1519 | struct fd lowerfd; |
1520 | struct cred *newcred; | |
1521 | const struct cred *oldcred; | |
1c1ca807 CB |
1522 | int newfd = -EBADF; |
1523 | long err = 0, ret = 0; | |
1524 | void __user *argp = (void __user *)arg; | |
45bd5d34 | 1525 | struct super_block *sb = file->f_path.dentry->d_sb; |
1c1ca807 CB |
1526 | struct btrfs_ioctl_vol_args *btrfs_v1 = NULL; |
1527 | struct btrfs_ioctl_vol_args_v2 *btrfs_v2 = NULL; | |
1528 | ||
1529 | ret = shiftfs_btrfs_ioctl_fd_replace(cmd, argp, &btrfs_v1, &btrfs_v2, | |
f7e373a5 | 1530 | &newfd); |
1c1ca807 CB |
1531 | if (ret < 0) |
1532 | return ret; | |
45bd5d34 CB |
1533 | |
1534 | ret = shiftfs_real_fdget(file, &lowerfd); | |
1535 | if (ret) | |
1c1ca807 | 1536 | goto out_restore; |
45bd5d34 | 1537 | |
f91b73d4 | 1538 | ret = shiftfs_override_ioctl_creds(cmd, sb, &oldcred, &newcred); |
45bd5d34 CB |
1539 | if (ret) |
1540 | goto out_fdput; | |
1541 | ||
1542 | ret = vfs_ioctl(lowerfd.file, cmd, arg); | |
1543 | ||
1544 | shiftfs_revert_ioctl_creds(oldcred, newcred); | |
1545 | ||
1546 | shiftfs_copyattr(file_inode(lowerfd.file), file_inode(file)); | |
1547 | shiftfs_copyflags(file_inode(lowerfd.file), file_inode(file)); | |
1548 | ||
1549 | out_fdput: | |
1550 | fdput(lowerfd); | |
1551 | ||
1c1ca807 | 1552 | out_restore: |
f7e373a5 | 1553 | err = shiftfs_btrfs_ioctl_fd_restore(cmd, newfd, argp, |
1c1ca807 CB |
1554 | btrfs_v1, btrfs_v2); |
1555 | if (!ret) | |
1556 | ret = err; | |
1557 | ||
45bd5d34 CB |
1558 | return ret; |
1559 | } | |
1560 | ||
d1aed12c | 1561 | static bool in_ioctl_whitelist(int flag, unsigned long arg) |
1c1ca807 | 1562 | { |
d1aed12c CB |
1563 | void __user *argp = (void __user *)arg; |
1564 | u64 flags = 0; | |
1565 | ||
1c1ca807 | 1566 | switch (flag) { |
d1aed12c CB |
1567 | case BTRFS_IOC_FS_INFO: |
1568 | return true; | |
1c1ca807 CB |
1569 | case BTRFS_IOC_SNAP_CREATE: |
1570 | return true; | |
1571 | case BTRFS_IOC_SNAP_CREATE_V2: | |
1572 | return true; | |
1573 | case BTRFS_IOC_SUBVOL_CREATE: | |
1574 | return true; | |
1575 | case BTRFS_IOC_SUBVOL_CREATE_V2: | |
d1aed12c CB |
1576 | return true; |
1577 | case BTRFS_IOC_SUBVOL_GETFLAGS: | |
1578 | return true; | |
1579 | case BTRFS_IOC_SUBVOL_SETFLAGS: | |
2af2b593 | 1580 | if (copy_from_user(&flags, argp, sizeof(flags))) |
d1aed12c CB |
1581 | return false; |
1582 | ||
1583 | if (flags & ~BTRFS_SUBVOL_RDONLY) | |
1584 | return false; | |
1585 | ||
1c1ca807 CB |
1586 | return true; |
1587 | case BTRFS_IOC_SNAP_DESTROY: | |
1588 | return true; | |
1589 | } | |
1590 | ||
1591 | return false; | |
1592 | } | |
1593 | ||
45bd5d34 CB |
1594 | static long shiftfs_ioctl(struct file *file, unsigned int cmd, |
1595 | unsigned long arg) | |
1596 | { | |
1597 | switch (cmd) { | |
1598 | case FS_IOC_GETVERSION: | |
1599 | /* fall through */ | |
1600 | case FS_IOC_GETFLAGS: | |
1601 | /* fall through */ | |
1602 | case FS_IOC_SETFLAGS: | |
1603 | break; | |
1604 | default: | |
d1aed12c | 1605 | if (!in_ioctl_whitelist(cmd, arg) || |
1c1ca807 CB |
1606 | !shiftfs_passthrough_ioctls(file->f_path.dentry->d_sb->s_fs_info)) |
1607 | return -ENOTTY; | |
45bd5d34 CB |
1608 | } |
1609 | ||
1610 | return shiftfs_real_ioctl(file, cmd, arg); | |
1611 | } | |
1612 | ||
1613 | static long shiftfs_compat_ioctl(struct file *file, unsigned int cmd, | |
1614 | unsigned long arg) | |
1615 | { | |
1616 | switch (cmd) { | |
1617 | case FS_IOC32_GETVERSION: | |
1618 | /* fall through */ | |
1619 | case FS_IOC32_GETFLAGS: | |
1620 | /* fall through */ | |
1621 | case FS_IOC32_SETFLAGS: | |
1622 | break; | |
1623 | default: | |
d1aed12c | 1624 | if (!in_ioctl_whitelist(cmd, arg) || |
1c1ca807 CB |
1625 | !shiftfs_passthrough_ioctls(file->f_path.dentry->d_sb->s_fs_info)) |
1626 | return -ENOIOCTLCMD; | |
45bd5d34 CB |
1627 | } |
1628 | ||
1629 | return shiftfs_real_ioctl(file, cmd, arg); | |
1630 | } | |
1631 | ||
1632 | enum shiftfs_copyop { | |
1633 | SHIFTFS_COPY, | |
1634 | SHIFTFS_CLONE, | |
1635 | SHIFTFS_DEDUPE, | |
1636 | }; | |
1637 | ||
1638 | static ssize_t shiftfs_copyfile(struct file *file_in, loff_t pos_in, | |
1639 | struct file *file_out, loff_t pos_out, u64 len, | |
1640 | unsigned int flags, enum shiftfs_copyop op) | |
1641 | { | |
1642 | ssize_t ret; | |
1643 | struct fd real_in, real_out; | |
1644 | const struct cred *oldcred; | |
1645 | struct inode *inode_out = file_inode(file_out); | |
1646 | struct inode *loweri = inode_out->i_private; | |
1647 | ||
1648 | ret = shiftfs_real_fdget(file_out, &real_out); | |
1649 | if (ret) | |
1650 | return ret; | |
1651 | ||
1652 | ret = shiftfs_real_fdget(file_in, &real_in); | |
1653 | if (ret) { | |
1654 | fdput(real_out); | |
1655 | return ret; | |
1656 | } | |
1657 | ||
1658 | oldcred = shiftfs_override_creds(inode_out->i_sb); | |
1659 | switch (op) { | |
1660 | case SHIFTFS_COPY: | |
1661 | ret = vfs_copy_file_range(real_in.file, pos_in, real_out.file, | |
1662 | pos_out, len, flags); | |
1663 | break; | |
1664 | ||
1665 | case SHIFTFS_CLONE: | |
1666 | ret = vfs_clone_file_range(real_in.file, pos_in, real_out.file, | |
1667 | pos_out, len, flags); | |
1668 | break; | |
1669 | ||
1670 | case SHIFTFS_DEDUPE: | |
1671 | ret = vfs_dedupe_file_range_one(real_in.file, pos_in, | |
1672 | real_out.file, pos_out, len, | |
1673 | flags); | |
1674 | break; | |
1675 | } | |
1676 | revert_creds(oldcred); | |
1677 | ||
1678 | /* Update size */ | |
1679 | shiftfs_copyattr(loweri, inode_out); | |
1680 | ||
1681 | fdput(real_in); | |
1682 | fdput(real_out); | |
1683 | ||
1684 | return ret; | |
1685 | } | |
1686 | ||
1687 | static ssize_t shiftfs_copy_file_range(struct file *file_in, loff_t pos_in, | |
1688 | struct file *file_out, loff_t pos_out, | |
1689 | size_t len, unsigned int flags) | |
1690 | { | |
1691 | return shiftfs_copyfile(file_in, pos_in, file_out, pos_out, len, flags, | |
1692 | SHIFTFS_COPY); | |
1693 | } | |
1694 | ||
1695 | static loff_t shiftfs_remap_file_range(struct file *file_in, loff_t pos_in, | |
1696 | struct file *file_out, loff_t pos_out, | |
1697 | loff_t len, unsigned int remap_flags) | |
1698 | { | |
1699 | enum shiftfs_copyop op; | |
1700 | ||
1701 | if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY)) | |
1702 | return -EINVAL; | |
1703 | ||
1704 | if (remap_flags & REMAP_FILE_DEDUP) | |
1705 | op = SHIFTFS_DEDUPE; | |
1706 | else | |
1707 | op = SHIFTFS_CLONE; | |
1708 | ||
1709 | return shiftfs_copyfile(file_in, pos_in, file_out, pos_out, len, | |
1710 | remap_flags, op); | |
1711 | } | |
1712 | ||
1713 | static int shiftfs_iterate_shared(struct file *file, struct dir_context *ctx) | |
1714 | { | |
1715 | const struct cred *oldcred; | |
1716 | int err = -ENOTDIR; | |
159ec080 | 1717 | struct file *realfile = file->private_data; |
45bd5d34 CB |
1718 | |
1719 | oldcred = shiftfs_override_creds(file->f_path.dentry->d_sb); | |
1720 | err = iterate_dir(realfile, ctx); | |
1721 | revert_creds(oldcred); | |
1722 | ||
1723 | return err; | |
1724 | } | |
1725 | ||
1726 | const struct file_operations shiftfs_file_operations = { | |
1727 | .open = shiftfs_open, | |
1728 | .release = shiftfs_release, | |
f3365a72 | 1729 | .llseek = shiftfs_file_llseek, |
45bd5d34 CB |
1730 | .read_iter = shiftfs_read_iter, |
1731 | .write_iter = shiftfs_write_iter, | |
1732 | .fsync = shiftfs_fsync, | |
1733 | .mmap = shiftfs_mmap, | |
1734 | .fallocate = shiftfs_fallocate, | |
1735 | .fadvise = shiftfs_fadvise, | |
1736 | .unlocked_ioctl = shiftfs_ioctl, | |
1737 | .compat_ioctl = shiftfs_compat_ioctl, | |
1738 | .copy_file_range = shiftfs_copy_file_range, | |
1739 | .remap_file_range = shiftfs_remap_file_range, | |
f133ae22 CB |
1740 | .splice_read = generic_file_splice_read, |
1741 | .splice_write = iter_file_splice_write, | |
45bd5d34 CB |
1742 | }; |
1743 | ||
1744 | const struct file_operations shiftfs_dir_operations = { | |
159ec080 CB |
1745 | .open = shiftfs_dir_open, |
1746 | .release = shiftfs_dir_release, | |
45bd5d34 CB |
1747 | .compat_ioctl = shiftfs_compat_ioctl, |
1748 | .fsync = shiftfs_fsync, | |
1749 | .iterate_shared = shiftfs_iterate_shared, | |
f3365a72 | 1750 | .llseek = shiftfs_dir_llseek, |
45bd5d34 | 1751 | .read = generic_read_dir, |
45bd5d34 CB |
1752 | .unlocked_ioctl = shiftfs_ioctl, |
1753 | }; | |
1754 | ||
1755 | static const struct address_space_operations shiftfs_aops = { | |
1756 | /* For O_DIRECT dentry_open() checks f_mapping->a_ops->direct_IO */ | |
1757 | .direct_IO = noop_direct_IO, | |
1758 | }; | |
1759 | ||
1760 | static void shiftfs_fill_inode(struct inode *inode, unsigned long ino, | |
1761 | umode_t mode, dev_t dev, struct dentry *dentry) | |
1762 | { | |
1763 | struct inode *loweri; | |
1764 | ||
1765 | inode->i_ino = ino; | |
1766 | inode->i_flags |= S_NOCMTIME; | |
1767 | ||
1768 | mode &= S_IFMT; | |
1769 | inode->i_mode = mode; | |
1770 | switch (mode & S_IFMT) { | |
1771 | case S_IFDIR: | |
1772 | inode->i_op = &shiftfs_dir_inode_operations; | |
1773 | inode->i_fop = &shiftfs_dir_operations; | |
1774 | break; | |
1775 | case S_IFLNK: | |
1776 | inode->i_op = &shiftfs_symlink_inode_operations; | |
1777 | break; | |
1778 | case S_IFREG: | |
1779 | inode->i_op = &shiftfs_file_inode_operations; | |
1780 | inode->i_fop = &shiftfs_file_operations; | |
1781 | inode->i_mapping->a_ops = &shiftfs_aops; | |
1782 | break; | |
1783 | default: | |
1784 | inode->i_op = &shiftfs_special_inode_operations; | |
1785 | init_special_inode(inode, mode, dev); | |
1786 | break; | |
1787 | } | |
1788 | ||
1789 | if (!dentry) | |
1790 | return; | |
1791 | ||
1792 | loweri = dentry->d_inode; | |
1793 | if (!loweri->i_op->get_link) | |
1794 | inode->i_opflags |= IOP_NOFOLLOW; | |
1795 | ||
1796 | shiftfs_copyattr(loweri, inode); | |
1797 | shiftfs_copyflags(loweri, inode); | |
1798 | set_nlink(inode, loweri->i_nlink); | |
1799 | } | |
1800 | ||
1801 | static int shiftfs_show_options(struct seq_file *m, struct dentry *dentry) | |
1802 | { | |
1803 | struct super_block *sb = dentry->d_sb; | |
1804 | struct shiftfs_super_info *sbinfo = sb->s_fs_info; | |
1805 | ||
1806 | if (sbinfo->mark) | |
1807 | seq_show_option(m, "mark", NULL); | |
1808 | ||
1809 | if (sbinfo->passthrough) | |
1810 | seq_printf(m, ",passthrough=%u", sbinfo->passthrough); | |
1811 | ||
1812 | return 0; | |
1813 | } | |
1814 | ||
1815 | static int shiftfs_statfs(struct dentry *dentry, struct kstatfs *buf) | |
1816 | { | |
1817 | struct super_block *sb = dentry->d_sb; | |
1818 | struct shiftfs_super_info *sbinfo = sb->s_fs_info; | |
1819 | struct dentry *root = sb->s_root; | |
1820 | struct dentry *realroot = root->d_fsdata; | |
1821 | struct path realpath = { .mnt = sbinfo->mnt, .dentry = realroot }; | |
1822 | int err; | |
1823 | ||
1824 | err = vfs_statfs(&realpath, buf); | |
8bde1547 | 1825 | if (err) |
45bd5d34 | 1826 | return err; |
8bde1547 | 1827 | |
45bd5d34 CB |
1828 | if (!shiftfs_passthrough_statfs(sbinfo)) |
1829 | buf->f_type = sb->s_magic; | |
8bde1547 | 1830 | |
45bd5d34 CB |
1831 | return 0; |
1832 | } | |
8bde1547 | 1833 | |
45bd5d34 CB |
1834 | static void shiftfs_evict_inode(struct inode *inode) |
1835 | { | |
1836 | struct inode *loweri = inode->i_private; | |
1837 | ||
1838 | clear_inode(inode); | |
1839 | ||
1840 | if (loweri) | |
1841 | iput(loweri); | |
1842 | } | |
1843 | ||
1844 | static void shiftfs_put_super(struct super_block *sb) | |
1845 | { | |
1846 | struct shiftfs_super_info *sbinfo = sb->s_fs_info; | |
1847 | ||
1848 | if (sbinfo) { | |
1849 | mntput(sbinfo->mnt); | |
1850 | put_cred(sbinfo->creator_cred); | |
1851 | kfree(sbinfo); | |
1852 | } | |
1853 | } | |
1854 | ||
1855 | static const struct xattr_handler shiftfs_xattr_handler = { | |
1856 | .prefix = "", | |
1857 | .get = shiftfs_xattr_get, | |
1858 | .set = shiftfs_xattr_set, | |
1859 | }; | |
1860 | ||
1861 | const struct xattr_handler *shiftfs_xattr_handlers[] = { | |
1862 | #ifdef CONFIG_SHIFT_FS_POSIX_ACL | |
1863 | &shiftfs_posix_acl_access_xattr_handler, | |
1864 | &shiftfs_posix_acl_default_xattr_handler, | |
1865 | #endif | |
1866 | &shiftfs_xattr_handler, | |
1867 | NULL | |
1868 | }; | |
1869 | ||
1870 | static inline bool passthrough_is_subset(int old_flags, int new_flags) | |
1871 | { | |
1872 | if ((new_flags & old_flags) != new_flags) | |
1873 | return false; | |
1874 | ||
1875 | return true; | |
1876 | } | |
1877 | ||
e36a1be6 CB |
1878 | static int shiftfs_super_check_flags(unsigned long old_flags, |
1879 | unsigned long new_flags) | |
1880 | { | |
1881 | if ((old_flags & SB_RDONLY) && !(new_flags & SB_RDONLY)) | |
1882 | return -EPERM; | |
1883 | ||
1884 | if ((old_flags & SB_NOSUID) && !(new_flags & SB_NOSUID)) | |
1885 | return -EPERM; | |
1886 | ||
1887 | if ((old_flags & SB_NODEV) && !(new_flags & SB_NODEV)) | |
1888 | return -EPERM; | |
1889 | ||
1890 | if ((old_flags & SB_NOEXEC) && !(new_flags & SB_NOEXEC)) | |
1891 | return -EPERM; | |
1892 | ||
1893 | if ((old_flags & SB_NOATIME) && !(new_flags & SB_NOATIME)) | |
1894 | return -EPERM; | |
1895 | ||
1896 | if ((old_flags & SB_NODIRATIME) && !(new_flags & SB_NODIRATIME)) | |
1897 | return -EPERM; | |
1898 | ||
1899 | if (!(old_flags & SB_POSIXACL) && (new_flags & SB_POSIXACL)) | |
1900 | return -EPERM; | |
1901 | ||
1902 | return 0; | |
1903 | } | |
1904 | ||
45bd5d34 CB |
1905 | static int shiftfs_remount(struct super_block *sb, int *flags, char *data) |
1906 | { | |
1907 | int err; | |
1908 | struct shiftfs_super_info new = {}; | |
1909 | struct shiftfs_super_info *info = sb->s_fs_info; | |
1910 | ||
1911 | err = shiftfs_parse_mount_options(&new, data); | |
8bde1547 | 1912 | if (err) |
45bd5d34 CB |
1913 | return err; |
1914 | ||
e36a1be6 CB |
1915 | err = shiftfs_super_check_flags(sb->s_flags, *flags); |
1916 | if (err) | |
1917 | return err; | |
1918 | ||
45bd5d34 CB |
1919 | /* Mark mount option cannot be changed. */ |
1920 | if (info->mark || (info->mark != new.mark)) | |
1921 | return -EPERM; | |
1922 | ||
1923 | if (info->passthrough != new.passthrough) { | |
1924 | /* Don't allow exceeding passthrough options of mark mount. */ | |
d6d053b7 | 1925 | if (!passthrough_is_subset(info->passthrough_mark, |
45bd5d34 CB |
1926 | info->passthrough)) |
1927 | return -EPERM; | |
1928 | ||
1929 | info->passthrough = new.passthrough; | |
1930 | } | |
1931 | ||
1932 | return 0; | |
1933 | } | |
8bde1547 | 1934 | |
45bd5d34 CB |
1935 | static const struct super_operations shiftfs_super_ops = { |
1936 | .put_super = shiftfs_put_super, | |
1937 | .show_options = shiftfs_show_options, | |
1938 | .statfs = shiftfs_statfs, | |
1939 | .remount_fs = shiftfs_remount, | |
1940 | .evict_inode = shiftfs_evict_inode, | |
1941 | }; | |
1942 | ||
1943 | struct shiftfs_data { | |
1944 | void *data; | |
1945 | const char *path; | |
1946 | }; | |
1947 | ||
e36a1be6 CB |
1948 | static void shiftfs_super_force_flags(struct super_block *sb, |
1949 | unsigned long lower_flags) | |
1950 | { | |
1951 | sb->s_flags |= lower_flags & (SB_RDONLY | SB_NOSUID | SB_NODEV | | |
1952 | SB_NOEXEC | SB_NOATIME | SB_NODIRATIME); | |
1953 | ||
1954 | if (!(lower_flags & SB_POSIXACL)) | |
1955 | sb->s_flags &= ~SB_POSIXACL; | |
1956 | } | |
1957 | ||
45bd5d34 CB |
1958 | static int shiftfs_fill_super(struct super_block *sb, void *raw_data, |
1959 | int silent) | |
1960 | { | |
1961 | int err; | |
1962 | struct path path = {}; | |
1963 | struct shiftfs_super_info *sbinfo_mp; | |
1964 | char *name = NULL; | |
1965 | struct inode *inode = NULL; | |
1966 | struct dentry *dentry = NULL; | |
1967 | struct shiftfs_data *data = raw_data; | |
1968 | struct shiftfs_super_info *sbinfo = NULL; | |
1969 | ||
1970 | if (!data->path) | |
1971 | return -EINVAL; | |
1972 | ||
1973 | sb->s_fs_info = kzalloc(sizeof(*sbinfo), GFP_KERNEL); | |
1974 | if (!sb->s_fs_info) | |
1975 | return -ENOMEM; | |
1976 | sbinfo = sb->s_fs_info; | |
1977 | ||
1978 | err = shiftfs_parse_mount_options(sbinfo, data->data); | |
1979 | if (err) | |
1980 | return err; | |
1981 | ||
1982 | /* to mount a mark, must be userns admin */ | |
1983 | if (!sbinfo->mark && !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) | |
1984 | return -EPERM; | |
1985 | ||
1986 | name = kstrdup(data->path, GFP_KERNEL); | |
1987 | if (!name) | |
1988 | return -ENOMEM; | |
1989 | ||
1990 | err = kern_path(name, LOOKUP_FOLLOW, &path); | |
1991 | if (err) | |
1992 | goto out_free_name; | |
8bde1547 JB |
1993 | |
1994 | if (!S_ISDIR(path.dentry->d_inode->i_mode)) { | |
1995 | err = -ENOTDIR; | |
45bd5d34 | 1996 | goto out_put_path; |
8bde1547 JB |
1997 | } |
1998 | ||
e36a1be6 CB |
1999 | sb->s_flags |= SB_POSIXACL; |
2000 | ||
45bd5d34 | 2001 | if (sbinfo->mark) { |
4f28efed | 2002 | struct cred *cred_tmp; |
45bd5d34 CB |
2003 | struct super_block *lower_sb = path.mnt->mnt_sb; |
2004 | ||
2005 | /* to mark a mount point, must root wrt lower s_user_ns */ | |
2006 | if (!ns_capable(lower_sb->s_user_ns, CAP_SYS_ADMIN)) { | |
2007 | err = -EPERM; | |
2008 | goto out_put_path; | |
2009 | } | |
8bde1547 | 2010 | |
8bde1547 JB |
2011 | /* |
2012 | * this part is visible unshifted, so make sure no | |
2013 | * executables that could be used to give suid | |
2014 | * privileges | |
2015 | */ | |
2016 | sb->s_iflags = SB_I_NOEXEC; | |
8bde1547 | 2017 | |
e36a1be6 CB |
2018 | shiftfs_super_force_flags(sb, lower_sb->s_flags); |
2019 | ||
8bde1547 | 2020 | /* |
45bd5d34 CB |
2021 | * Handle nesting of shiftfs mounts by referring this mark |
2022 | * mount back to the original mark mount. This is more | |
2023 | * efficient and alleviates concerns about stack depth. | |
8bde1547 | 2024 | */ |
45bd5d34 CB |
2025 | if (lower_sb->s_magic == SHIFTFS_MAGIC) { |
2026 | sbinfo_mp = lower_sb->s_fs_info; | |
2027 | ||
2028 | /* Doesn't make sense to mark a mark mount */ | |
2029 | if (sbinfo_mp->mark) { | |
2030 | err = -EINVAL; | |
2031 | goto out_put_path; | |
2032 | } | |
2033 | ||
2034 | if (!passthrough_is_subset(sbinfo_mp->passthrough, | |
2035 | sbinfo->passthrough)) { | |
2036 | err = -EPERM; | |
2037 | goto out_put_path; | |
2038 | } | |
2039 | ||
2040 | sbinfo->mnt = mntget(sbinfo_mp->mnt); | |
2041 | dentry = dget(path.dentry->d_fsdata); | |
d6d053b7 CB |
2042 | /* |
2043 | * Copy up the passthrough mount options from the | |
2044 | * parent mark mountpoint. | |
2045 | */ | |
2046 | sbinfo->passthrough_mark = sbinfo_mp->passthrough_mark; | |
e33fe991 | 2047 | sbinfo->creator_cred = get_cred(sbinfo_mp->creator_cred); |
45bd5d34 CB |
2048 | } else { |
2049 | sbinfo->mnt = mntget(path.mnt); | |
2050 | dentry = dget(path.dentry); | |
d6d053b7 CB |
2051 | /* |
2052 | * For a new mark passthrough_mark and passthrough | |
2053 | * are identical. | |
2054 | */ | |
2055 | sbinfo->passthrough_mark = sbinfo->passthrough; | |
45bd5d34 | 2056 | |
e33fe991 CB |
2057 | cred_tmp = prepare_creds(); |
2058 | if (!cred_tmp) { | |
2059 | err = -ENOMEM; | |
2060 | goto out_put_path; | |
2061 | } | |
2062 | /* Don't override disk quota limits or use reserved space. */ | |
2063 | cap_lower(cred_tmp->cap_effective, CAP_SYS_RESOURCE); | |
2064 | sbinfo->creator_cred = cred_tmp; | |
45bd5d34 CB |
2065 | } |
2066 | } else { | |
2067 | /* | |
2068 | * This leg executes if we're admin capable in the namespace, | |
2069 | * so be very careful. | |
2070 | */ | |
2071 | err = -EPERM; | |
8bde1547 | 2072 | if (path.dentry->d_sb->s_magic != SHIFTFS_MAGIC) |
45bd5d34 CB |
2073 | goto out_put_path; |
2074 | ||
2075 | sbinfo_mp = path.dentry->d_sb->s_fs_info; | |
2076 | if (!sbinfo_mp->mark) | |
2077 | goto out_put_path; | |
2078 | ||
2079 | if (!passthrough_is_subset(sbinfo_mp->passthrough, | |
2080 | sbinfo->passthrough)) | |
2081 | goto out_put_path; | |
2082 | ||
2083 | sbinfo->mnt = mntget(sbinfo_mp->mnt); | |
2084 | sbinfo->creator_cred = get_cred(sbinfo_mp->creator_cred); | |
8bde1547 | 2085 | dentry = dget(path.dentry->d_fsdata); |
d6d053b7 CB |
2086 | /* |
2087 | * Copy up passthrough settings from mark mountpoint so we can | |
2088 | * verify when the overlay wants to remount with different | |
2089 | * passthrough settings. | |
2090 | */ | |
2091 | sbinfo->passthrough_mark = sbinfo_mp->passthrough; | |
e36a1be6 | 2092 | shiftfs_super_force_flags(sb, path.mnt->mnt_sb->s_flags); |
45bd5d34 CB |
2093 | } |
2094 | ||
2095 | sb->s_stack_depth = dentry->d_sb->s_stack_depth + 1; | |
2096 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
2097 | printk(KERN_ERR "shiftfs: maximum stacking depth exceeded\n"); | |
2098 | err = -EINVAL; | |
2099 | goto out_put_path; | |
2100 | } | |
2101 | ||
2102 | inode = new_inode(sb); | |
2103 | if (!inode) { | |
2104 | err = -ENOMEM; | |
2105 | goto out_put_path; | |
8bde1547 | 2106 | } |
45bd5d34 CB |
2107 | shiftfs_fill_inode(inode, dentry->d_inode->i_ino, S_IFDIR, 0, dentry); |
2108 | ||
2109 | ihold(dentry->d_inode); | |
2110 | inode->i_private = dentry->d_inode; | |
2111 | ||
8bde1547 | 2112 | sb->s_magic = SHIFTFS_MAGIC; |
f9619714 | 2113 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
8bde1547 JB |
2114 | sb->s_op = &shiftfs_super_ops; |
2115 | sb->s_xattr = shiftfs_xattr_handlers; | |
2116 | sb->s_d_op = &shiftfs_dentry_ops; | |
45bd5d34 CB |
2117 | sb->s_root = d_make_root(inode); |
2118 | if (!sb->s_root) { | |
2119 | err = -ENOMEM; | |
2120 | goto out_put_path; | |
2121 | } | |
2122 | ||
8bde1547 | 2123 | sb->s_root->d_fsdata = dentry; |
45bd5d34 CB |
2124 | sbinfo->userns = get_user_ns(dentry->d_sb->s_user_ns); |
2125 | shiftfs_copyattr(dentry->d_inode, sb->s_root->d_inode); | |
8bde1547 | 2126 | |
45bd5d34 CB |
2127 | dentry = NULL; |
2128 | err = 0; | |
8bde1547 | 2129 | |
45bd5d34 | 2130 | out_put_path: |
8bde1547 | 2131 | path_put(&path); |
45bd5d34 CB |
2132 | |
2133 | out_free_name: | |
8bde1547 | 2134 | kfree(name); |
45bd5d34 CB |
2135 | |
2136 | dput(dentry); | |
2137 | ||
8bde1547 JB |
2138 | return err; |
2139 | } | |
2140 | ||
2141 | static struct dentry *shiftfs_mount(struct file_system_type *fs_type, | |
2142 | int flags, const char *dev_name, void *data) | |
2143 | { | |
2144 | struct shiftfs_data d = { data, dev_name }; | |
2145 | ||
2146 | return mount_nodev(fs_type, flags, &d, shiftfs_fill_super); | |
2147 | } | |
2148 | ||
2149 | static struct file_system_type shiftfs_type = { | |
2150 | .owner = THIS_MODULE, | |
2151 | .name = "shiftfs", | |
2152 | .mount = shiftfs_mount, | |
2153 | .kill_sb = kill_anon_super, | |
2154 | .fs_flags = FS_USERNS_MOUNT, | |
2155 | }; | |
2156 | ||
2157 | static int __init shiftfs_init(void) | |
2158 | { | |
2159 | return register_filesystem(&shiftfs_type); | |
2160 | } | |
2161 | ||
2162 | static void __exit shiftfs_exit(void) | |
2163 | { | |
2164 | unregister_filesystem(&shiftfs_type); | |
2165 | } | |
2166 | ||
2167 | MODULE_ALIAS_FS("shiftfs"); | |
2168 | MODULE_AUTHOR("James Bottomley"); | |
45bd5d34 CB |
2169 | MODULE_AUTHOR("Seth Forshee <seth.forshee@canonical.com>"); |
2170 | MODULE_AUTHOR("Christian Brauner <christian.brauner@ubuntu.com>"); | |
2171 | MODULE_DESCRIPTION("id shifting filesystem"); | |
8bde1547 JB |
2172 | MODULE_LICENSE("GPL v2"); |
2173 | module_init(shiftfs_init) | |
2174 | module_exit(shiftfs_exit) |