1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/pagemap.h>
12 #include <linux/file.h>
13 #include <linux/fs_context.h>
14 #include <linux/moduleparam.h>
15 #include <linux/sched.h>
16 #include <linux/namei.h>
17 #include <linux/slab.h>
18 #include <linux/xattr.h>
19 #include <linux/iversion.h>
20 #include <linux/posix_acl.h>
21 #include <linux/security.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24
25 static bool __read_mostly allow_sys_admin_access;
26 module_param(allow_sys_admin_access, bool, 0644);
27 MODULE_PARM_DESC(allow_sys_admin_access,
28 "Allow users with CAP_SYS_ADMIN in initial userns to bypass allow_other access check");
29
30 static void fuse_advise_use_readdirplus(struct inode *dir)
31 {
32 struct fuse_inode *fi = get_fuse_inode(dir);
33
34 set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state);
35 }
36
37 #if BITS_PER_LONG >= 64
38 static inline void __fuse_dentry_settime(struct dentry *entry, u64 time)
39 {
40 entry->d_fsdata = (void *) time;
41 }
42
43 static inline u64 fuse_dentry_time(const struct dentry *entry)
44 {
45 return (u64)entry->d_fsdata;
46 }
47
48 #else
49 union fuse_dentry {
50 u64 time;
51 struct rcu_head rcu;
52 };
53
54 static inline void __fuse_dentry_settime(struct dentry *dentry, u64 time)
55 {
56 ((union fuse_dentry *) dentry->d_fsdata)->time = time;
57 }
58
59 static inline u64 fuse_dentry_time(const struct dentry *entry)
60 {
61 return ((union fuse_dentry *) entry->d_fsdata)->time;
62 }
63 #endif
64
65 static void fuse_dentry_settime(struct dentry *dentry, u64 time)
66 {
67 struct fuse_conn *fc = get_fuse_conn_super(dentry->d_sb);
68 bool delete = !time && fc->delete_stale;
69 /*
70 * Mess with DCACHE_OP_DELETE because dput() will be faster without it.
71 * Don't care about races, either way it's just an optimization
72 */
73 if ((!delete && (dentry->d_flags & DCACHE_OP_DELETE)) ||
74 (delete && !(dentry->d_flags & DCACHE_OP_DELETE))) {
75 spin_lock(&dentry->d_lock);
76 if (!delete)
77 dentry->d_flags &= ~DCACHE_OP_DELETE;
78 else
79 dentry->d_flags |= DCACHE_OP_DELETE;
80 spin_unlock(&dentry->d_lock);
81 }
82
83 __fuse_dentry_settime(dentry, time);
84 }
85
86 /*
87 * FUSE caches dentries and attributes with separate timeout. The
88 * time in jiffies until the dentry/attributes are valid is stored in
89 * dentry->d_fsdata and fuse_inode->i_time respectively.
90 */
91
92 /*
93 * Calculate the time in jiffies until a dentry/attributes are valid
94 */
95 u64 fuse_time_to_jiffies(u64 sec, u32 nsec)
96 {
97 if (sec || nsec) {
98 struct timespec64 ts = {
99 sec,
100 min_t(u32, nsec, NSEC_PER_SEC - 1)
101 };
102
103 return get_jiffies_64() + timespec64_to_jiffies(&ts);
104 } else
105 return 0;
106 }
107
108 /*
109 * Set dentry and possibly attribute timeouts from the lookup/mk*
110 * replies
111 */
112 void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o)
113 {
114 fuse_dentry_settime(entry,
115 fuse_time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
116 }
117
118 void fuse_invalidate_attr_mask(struct inode *inode, u32 mask)
119 {
120 set_mask_bits(&get_fuse_inode(inode)->inval_mask, 0, mask);
121 }
122
123 /*
124 * Mark the attributes as stale, so that at the next call to
125 * ->getattr() they will be fetched from userspace
126 */
127 void fuse_invalidate_attr(struct inode *inode)
128 {
129 fuse_invalidate_attr_mask(inode, STATX_BASIC_STATS);
130 }
131
132 static void fuse_dir_changed(struct inode *dir)
133 {
134 fuse_invalidate_attr(dir);
135 inode_maybe_inc_iversion(dir, false);
136 }
137
138 /*
139 * Mark the attributes as stale due to an atime change. Avoid the invalidate if
140 * atime is not used.
141 */
142 void fuse_invalidate_atime(struct inode *inode)
143 {
144 if (!IS_RDONLY(inode))
145 fuse_invalidate_attr_mask(inode, STATX_ATIME);
146 }
147
148 /*
149 * Just mark the entry as stale, so that a next attempt to look it up
150 * will result in a new lookup call to userspace
151 *
152 * This is called when a dentry is about to become negative and the
153 * timeout is unknown (unlink, rmdir, rename and in some cases
154 * lookup)
155 */
156 void fuse_invalidate_entry_cache(struct dentry *entry)
157 {
158 fuse_dentry_settime(entry, 0);
159 }
160
161 /*
162 * Same as fuse_invalidate_entry_cache(), but also try to remove the
163 * dentry from the hash
164 */
165 static void fuse_invalidate_entry(struct dentry *entry)
166 {
167 d_invalidate(entry);
168 fuse_invalidate_entry_cache(entry);
169 }
170
171 static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args,
172 u64 nodeid, const struct qstr *name,
173 struct fuse_entry_out *outarg)
174 {
175 memset(outarg, 0, sizeof(struct fuse_entry_out));
176 args->opcode = FUSE_LOOKUP;
177 args->nodeid = nodeid;
178 args->in_numargs = 1;
179 args->in_args[0].size = name->len + 1;
180 args->in_args[0].value = name->name;
181 args->out_numargs = 1;
182 args->out_args[0].size = sizeof(struct fuse_entry_out);
183 args->out_args[0].value = outarg;
184 }
185
186 /*
187 * Check whether the dentry is still valid
188 *
189 * If the entry validity timeout has expired and the dentry is
190 * positive, try to redo the lookup. If the lookup results in a
191 * different inode, then let the VFS invalidate the dentry and redo
192 * the lookup once more. If the lookup results in the same inode,
193 * then refresh the attributes, timeouts and mark the dentry valid.
194 */
195 static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
196 {
197 struct inode *inode;
198 struct dentry *parent;
199 struct fuse_mount *fm;
200 struct fuse_inode *fi;
201 int ret;
202
203 inode = d_inode_rcu(entry);
204 if (inode && fuse_is_bad(inode))
205 goto invalid;
206 else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
207 (flags & (LOOKUP_EXCL | LOOKUP_REVAL | LOOKUP_RENAME_TARGET))) {
208 struct fuse_entry_out outarg;
209 FUSE_ARGS(args);
210 struct fuse_forget_link *forget;
211 u64 attr_version;
212
213 /* For negative dentries, always do a fresh lookup */
214 if (!inode)
215 goto invalid;
216
217 ret = -ECHILD;
218 if (flags & LOOKUP_RCU)
219 goto out;
220
221 fm = get_fuse_mount(inode);
222
223 forget = fuse_alloc_forget();
224 ret = -ENOMEM;
225 if (!forget)
226 goto out;
227
228 attr_version = fuse_get_attr_version(fm->fc);
229
230 parent = dget_parent(entry);
231 fuse_lookup_init(fm->fc, &args, get_node_id(d_inode(parent)),
232 &entry->d_name, &outarg);
233 ret = fuse_simple_request(fm, &args);
234 dput(parent);
235 /* Zero nodeid is same as -ENOENT */
236 if (!ret && !outarg.nodeid)
237 ret = -ENOENT;
238 if (!ret) {
239 fi = get_fuse_inode(inode);
240 if (outarg.nodeid != get_node_id(inode) ||
241 (bool) IS_AUTOMOUNT(inode) != (bool) (outarg.attr.flags & FUSE_ATTR_SUBMOUNT)) {
242 fuse_queue_forget(fm->fc, forget,
243 outarg.nodeid, 1);
244 goto invalid;
245 }
246 spin_lock(&fi->lock);
247 fi->nlookup++;
248 spin_unlock(&fi->lock);
249 }
250 kfree(forget);
251 if (ret == -ENOMEM || ret == -EINTR)
252 goto out;
253 if (ret || fuse_invalid_attr(&outarg.attr) ||
254 fuse_stale_inode(inode, outarg.generation, &outarg.attr))
255 goto invalid;
256
257 forget_all_cached_acls(inode);
258 fuse_change_attributes(inode, &outarg.attr, NULL,
259 ATTR_TIMEOUT(&outarg),
260 attr_version);
261 fuse_change_entry_timeout(entry, &outarg);
262 } else if (inode) {
263 fi = get_fuse_inode(inode);
264 if (flags & LOOKUP_RCU) {
265 if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
266 return -ECHILD;
267 } else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
268 parent = dget_parent(entry);
269 fuse_advise_use_readdirplus(d_inode(parent));
270 dput(parent);
271 }
272 }
273 ret = 1;
274 out:
275 return ret;
276
277 invalid:
278 ret = 0;
279 goto out;
280 }
281
282 #if BITS_PER_LONG < 64
283 static int fuse_dentry_init(struct dentry *dentry)
284 {
285 dentry->d_fsdata = kzalloc(sizeof(union fuse_dentry),
286 GFP_KERNEL_ACCOUNT | __GFP_RECLAIMABLE);
287
288 return dentry->d_fsdata ? 0 : -ENOMEM;
289 }
290 static void fuse_dentry_release(struct dentry *dentry)
291 {
292 union fuse_dentry *fd = dentry->d_fsdata;
293
294 kfree_rcu(fd, rcu);
295 }
296 #endif
297
298 static int fuse_dentry_delete(const struct dentry *dentry)
299 {
300 return time_before64(fuse_dentry_time(dentry), get_jiffies_64());
301 }
302
303 /*
304 * Create a fuse_mount object with a new superblock (with path->dentry
305 * as the root), and return that mount so it can be auto-mounted on
306 * @path.
307 */
308 static struct vfsmount *fuse_dentry_automount(struct path *path)
309 {
310 struct fs_context *fsc;
311 struct vfsmount *mnt;
312 struct fuse_inode *mp_fi = get_fuse_inode(d_inode(path->dentry));
313
314 fsc = fs_context_for_submount(path->mnt->mnt_sb->s_type, path->dentry);
315 if (IS_ERR(fsc))
316 return ERR_CAST(fsc);
317
318 /* Pass the FUSE inode of the mount for fuse_get_tree_submount() */
319 fsc->fs_private = mp_fi;
320
321 /* Create the submount */
322 mnt = fc_mount(fsc);
323 if (!IS_ERR(mnt))
324 mntget(mnt);
325
326 put_fs_context(fsc);
327 return mnt;
328 }
329
330 const struct dentry_operations fuse_dentry_operations = {
331 .d_revalidate = fuse_dentry_revalidate,
332 .d_delete = fuse_dentry_delete,
333 #if BITS_PER_LONG < 64
334 .d_init = fuse_dentry_init,
335 .d_release = fuse_dentry_release,
336 #endif
337 .d_automount = fuse_dentry_automount,
338 };
339
340 const struct dentry_operations fuse_root_dentry_operations = {
341 #if BITS_PER_LONG < 64
342 .d_init = fuse_dentry_init,
343 .d_release = fuse_dentry_release,
344 #endif
345 };
346
347 int fuse_valid_type(int m)
348 {
349 return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
350 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
351 }
352
353 static bool fuse_valid_size(u64 size)
354 {
355 return size <= LLONG_MAX;
356 }
357
358 bool fuse_invalid_attr(struct fuse_attr *attr)
359 {
360 return !fuse_valid_type(attr->mode) || !fuse_valid_size(attr->size);
361 }
362
363 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
364 struct fuse_entry_out *outarg, struct inode **inode)
365 {
366 struct fuse_mount *fm = get_fuse_mount_super(sb);
367 FUSE_ARGS(args);
368 struct fuse_forget_link *forget;
369 u64 attr_version;
370 int err;
371
372 *inode = NULL;
373 err = -ENAMETOOLONG;
374 if (name->len > FUSE_NAME_MAX)
375 goto out;
376
377
378 forget = fuse_alloc_forget();
379 err = -ENOMEM;
380 if (!forget)
381 goto out;
382
383 attr_version = fuse_get_attr_version(fm->fc);
384
385 fuse_lookup_init(fm->fc, &args, nodeid, name, outarg);
386 err = fuse_simple_request(fm, &args);
387 /* Zero nodeid is same as -ENOENT, but with valid timeout */
388 if (err || !outarg->nodeid)
389 goto out_put_forget;
390
391 err = -EIO;
392 if (fuse_invalid_attr(&outarg->attr))
393 goto out_put_forget;
394 if (outarg->nodeid == FUSE_ROOT_ID && outarg->generation != 0) {
395 pr_warn_once("root generation should be zero\n");
396 outarg->generation = 0;
397 }
398
399 *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
400 &outarg->attr, ATTR_TIMEOUT(outarg),
401 attr_version);
402 err = -ENOMEM;
403 if (!*inode) {
404 fuse_queue_forget(fm->fc, forget, outarg->nodeid, 1);
405 goto out;
406 }
407 err = 0;
408
409 out_put_forget:
410 kfree(forget);
411 out:
412 return err;
413 }
414
415 static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
416 unsigned int flags)
417 {
418 int err;
419 struct fuse_entry_out outarg;
420 struct inode *inode;
421 struct dentry *newent;
422 bool outarg_valid = true;
423 bool locked;
424
425 if (fuse_is_bad(dir))
426 return ERR_PTR(-EIO);
427
428 locked = fuse_lock_inode(dir);
429 err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
430 &outarg, &inode);
431 fuse_unlock_inode(dir, locked);
432 if (err == -ENOENT) {
433 outarg_valid = false;
434 err = 0;
435 }
436 if (err)
437 goto out_err;
438
439 err = -EIO;
440 if (inode && get_node_id(inode) == FUSE_ROOT_ID)
441 goto out_iput;
442
443 newent = d_splice_alias(inode, entry);
444 err = PTR_ERR(newent);
445 if (IS_ERR(newent))
446 goto out_err;
447
448 entry = newent ? newent : entry;
449 if (outarg_valid)
450 fuse_change_entry_timeout(entry, &outarg);
451 else
452 fuse_invalidate_entry_cache(entry);
453
454 if (inode)
455 fuse_advise_use_readdirplus(dir);
456 return newent;
457
458 out_iput:
459 iput(inode);
460 out_err:
461 return ERR_PTR(err);
462 }
463
464 static int get_security_context(struct dentry *entry, umode_t mode,
465 struct fuse_in_arg *ext)
466 {
467 struct fuse_secctx *fctx;
468 struct fuse_secctx_header *header;
469 void *ctx = NULL, *ptr;
470 u32 ctxlen, total_len = sizeof(*header);
471 int err, nr_ctx = 0;
472 const char *name;
473 size_t namelen;
474
475 err = security_dentry_init_security(entry, mode, &entry->d_name,
476 &name, &ctx, &ctxlen);
477 if (err) {
478 if (err != -EOPNOTSUPP)
479 goto out_err;
480 /* No LSM is supporting this security hook. Ignore error */
481 ctxlen = 0;
482 ctx = NULL;
483 }
484
485 if (ctxlen) {
486 nr_ctx = 1;
487 namelen = strlen(name) + 1;
488 err = -EIO;
489 if (WARN_ON(namelen > XATTR_NAME_MAX + 1 || ctxlen > S32_MAX))
490 goto out_err;
491 total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen + ctxlen);
492 }
493
494 err = -ENOMEM;
495 header = ptr = kzalloc(total_len, GFP_KERNEL);
496 if (!ptr)
497 goto out_err;
498
499 header->nr_secctx = nr_ctx;
500 header->size = total_len;
501 ptr += sizeof(*header);
502 if (nr_ctx) {
503 fctx = ptr;
504 fctx->size = ctxlen;
505 ptr += sizeof(*fctx);
506
507 strcpy(ptr, name);
508 ptr += namelen;
509
510 memcpy(ptr, ctx, ctxlen);
511 }
512 ext->size = total_len;
513 ext->value = header;
514 err = 0;
515 out_err:
516 kfree(ctx);
517 return err;
518 }
519
520 static void *extend_arg(struct fuse_in_arg *buf, u32 bytes)
521 {
522 void *p;
523 u32 newlen = buf->size + bytes;
524
525 p = krealloc(buf->value, newlen, GFP_KERNEL);
526 if (!p) {
527 kfree(buf->value);
528 buf->size = 0;
529 buf->value = NULL;
530 return NULL;
531 }
532
533 memset(p + buf->size, 0, bytes);
534 buf->value = p;
535 buf->size = newlen;
536
537 return p + newlen - bytes;
538 }
539
540 static u32 fuse_ext_size(size_t size)
541 {
542 return FUSE_REC_ALIGN(sizeof(struct fuse_ext_header) + size);
543 }
544
545 /*
546 * This adds just a single supplementary group that matches the parent's group.
547 */
548 static int get_create_supp_group(struct inode *dir, struct fuse_in_arg *ext)
549 {
550 struct fuse_conn *fc = get_fuse_conn(dir);
551 struct fuse_ext_header *xh;
552 struct fuse_supp_groups *sg;
553 kgid_t kgid = dir->i_gid;
554 gid_t parent_gid = from_kgid(fc->user_ns, kgid);
555 u32 sg_len = fuse_ext_size(sizeof(*sg) + sizeof(sg->groups[0]));
556
557 if (parent_gid == (gid_t) -1 || gid_eq(kgid, current_fsgid()) ||
558 !in_group_p(kgid))
559 return 0;
560
561 xh = extend_arg(ext, sg_len);
562 if (!xh)
563 return -ENOMEM;
564
565 xh->size = sg_len;
566 xh->type = FUSE_EXT_GROUPS;
567
568 sg = (struct fuse_supp_groups *) &xh[1];
569 sg->nr_groups = 1;
570 sg->groups[0] = parent_gid;
571
572 return 0;
573 }
574
575 static int get_create_ext(struct fuse_args *args,
576 struct inode *dir, struct dentry *dentry,
577 umode_t mode)
578 {
579 struct fuse_conn *fc = get_fuse_conn_super(dentry->d_sb);
580 struct fuse_in_arg ext = { .size = 0, .value = NULL };
581 int err = 0;
582
583 if (fc->init_security)
584 err = get_security_context(dentry, mode, &ext);
585 if (!err && fc->create_supp_group)
586 err = get_create_supp_group(dir, &ext);
587
588 if (!err && ext.size) {
589 WARN_ON(args->in_numargs >= ARRAY_SIZE(args->in_args));
590 args->is_ext = true;
591 args->ext_idx = args->in_numargs++;
592 args->in_args[args->ext_idx] = ext;
593 } else {
594 kfree(ext.value);
595 }
596
597 return err;
598 }
599
600 static void free_ext_value(struct fuse_args *args)
601 {
602 if (args->is_ext)
603 kfree(args->in_args[args->ext_idx].value);
604 }
605
606 /*
607 * Atomic create+open operation
608 *
609 * If the filesystem doesn't support this, then fall back to separate
610 * 'mknod' + 'open' requests.
611 */
612 static int fuse_create_open(struct inode *dir, struct dentry *entry,
613 struct file *file, unsigned int flags,
614 umode_t mode, u32 opcode)
615 {
616 int err;
617 struct inode *inode;
618 struct fuse_mount *fm = get_fuse_mount(dir);
619 FUSE_ARGS(args);
620 struct fuse_forget_link *forget;
621 struct fuse_create_in inarg;
622 struct fuse_open_out *outopenp;
623 struct fuse_entry_out outentry;
624 struct fuse_inode *fi;
625 struct fuse_file *ff;
626 bool trunc = flags & O_TRUNC;
627
628 /* Userspace expects S_IFREG in create mode */
629 BUG_ON((mode & S_IFMT) != S_IFREG);
630
631 forget = fuse_alloc_forget();
632 err = -ENOMEM;
633 if (!forget)
634 goto out_err;
635
636 err = -ENOMEM;
637 ff = fuse_file_alloc(fm, true);
638 if (!ff)
639 goto out_put_forget_req;
640
641 if (!fm->fc->dont_mask)
642 mode &= ~current_umask();
643
644 flags &= ~O_NOCTTY;
645 memset(&inarg, 0, sizeof(inarg));
646 memset(&outentry, 0, sizeof(outentry));
647 inarg.flags = flags;
648 inarg.mode = mode;
649 inarg.umask = current_umask();
650
651 if (fm->fc->handle_killpriv_v2 && trunc &&
652 !(flags & O_EXCL) && !capable(CAP_FSETID)) {
653 inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
654 }
655
656 args.opcode = opcode;
657 args.nodeid = get_node_id(dir);
658 args.in_numargs = 2;
659 args.in_args[0].size = sizeof(inarg);
660 args.in_args[0].value = &inarg;
661 args.in_args[1].size = entry->d_name.len + 1;
662 args.in_args[1].value = entry->d_name.name;
663 args.out_numargs = 2;
664 args.out_args[0].size = sizeof(outentry);
665 args.out_args[0].value = &outentry;
666 /* Store outarg for fuse_finish_open() */
667 outopenp = &ff->args->open_outarg;
668 args.out_args[1].size = sizeof(*outopenp);
669 args.out_args[1].value = outopenp;
670
671 err = get_create_ext(&args, dir, entry, mode);
672 if (err)
673 goto out_free_ff;
674
675 err = fuse_simple_request(fm, &args);
676 free_ext_value(&args);
677 if (err)
678 goto out_free_ff;
679
680 err = -EIO;
681 if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid) ||
682 fuse_invalid_attr(&outentry.attr))
683 goto out_free_ff;
684
685 ff->fh = outopenp->fh;
686 ff->nodeid = outentry.nodeid;
687 ff->open_flags = outopenp->open_flags;
688 inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
689 &outentry.attr, ATTR_TIMEOUT(&outentry), 0);
690 if (!inode) {
691 flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
692 fuse_sync_release(NULL, ff, flags);
693 fuse_queue_forget(fm->fc, forget, outentry.nodeid, 1);
694 err = -ENOMEM;
695 goto out_err;
696 }
697 kfree(forget);
698 d_instantiate(entry, inode);
699 fuse_change_entry_timeout(entry, &outentry);
700 fuse_dir_changed(dir);
701 err = generic_file_open(inode, file);
702 if (!err) {
703 file->private_data = ff;
704 err = finish_open(file, entry, fuse_finish_open);
705 }
706 if (err) {
707 fi = get_fuse_inode(inode);
708 fuse_sync_release(fi, ff, flags);
709 } else {
710 if (fm->fc->atomic_o_trunc && trunc)
711 truncate_pagecache(inode, 0);
712 else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
713 invalidate_inode_pages2(inode->i_mapping);
714 }
715 return err;
716
717 out_free_ff:
718 fuse_file_free(ff);
719 out_put_forget_req:
720 kfree(forget);
721 out_err:
722 return err;
723 }
724
725 static int fuse_mknod(struct mnt_idmap *, struct inode *, struct dentry *,
726 umode_t, dev_t);
727 static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
728 struct file *file, unsigned flags,
729 umode_t mode)
730 {
731 int err;
732 struct fuse_conn *fc = get_fuse_conn(dir);
733 struct dentry *res = NULL;
734
735 if (fuse_is_bad(dir))
736 return -EIO;
737
738 if (d_in_lookup(entry)) {
739 res = fuse_lookup(dir, entry, 0);
740 if (IS_ERR(res))
741 return PTR_ERR(res);
742
743 if (res)
744 entry = res;
745 }
746
747 if (!(flags & O_CREAT) || d_really_is_positive(entry))
748 goto no_open;
749
750 /* Only creates */
751 file->f_mode |= FMODE_CREATED;
752
753 if (fc->no_create)
754 goto mknod;
755
756 err = fuse_create_open(dir, entry, file, flags, mode, FUSE_CREATE);
757 if (err == -ENOSYS) {
758 fc->no_create = 1;
759 goto mknod;
760 } else if (err == -EEXIST)
761 fuse_invalidate_entry(entry);
762 out_dput:
763 dput(res);
764 return err;
765
766 mknod:
767 err = fuse_mknod(&nop_mnt_idmap, dir, entry, mode, 0);
768 if (err)
769 goto out_dput;
770 no_open:
771 return finish_no_open(file, res);
772 }
773
774 /*
775 * Code shared between mknod, mkdir, symlink and link
776 */
777 static int create_new_entry(struct fuse_mount *fm, struct fuse_args *args,
778 struct inode *dir, struct dentry *entry,
779 umode_t mode)
780 {
781 struct fuse_entry_out outarg;
782 struct inode *inode;
783 struct dentry *d;
784 int err;
785 struct fuse_forget_link *forget;
786
787 if (fuse_is_bad(dir))
788 return -EIO;
789
790 forget = fuse_alloc_forget();
791 if (!forget)
792 return -ENOMEM;
793
794 memset(&outarg, 0, sizeof(outarg));
795 args->nodeid = get_node_id(dir);
796 args->out_numargs = 1;
797 args->out_args[0].size = sizeof(outarg);
798 args->out_args[0].value = &outarg;
799
800 if (args->opcode != FUSE_LINK) {
801 err = get_create_ext(args, dir, entry, mode);
802 if (err)
803 goto out_put_forget_req;
804 }
805
806 err = fuse_simple_request(fm, args);
807 free_ext_value(args);
808 if (err)
809 goto out_put_forget_req;
810
811 err = -EIO;
812 if (invalid_nodeid(outarg.nodeid) || fuse_invalid_attr(&outarg.attr))
813 goto out_put_forget_req;
814
815 if ((outarg.attr.mode ^ mode) & S_IFMT)
816 goto out_put_forget_req;
817
818 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
819 &outarg.attr, ATTR_TIMEOUT(&outarg), 0);
820 if (!inode) {
821 fuse_queue_forget(fm->fc, forget, outarg.nodeid, 1);
822 return -ENOMEM;
823 }
824 kfree(forget);
825
826 d_drop(entry);
827 d = d_splice_alias(inode, entry);
828 if (IS_ERR(d))
829 return PTR_ERR(d);
830
831 if (d) {
832 fuse_change_entry_timeout(d, &outarg);
833 dput(d);
834 } else {
835 fuse_change_entry_timeout(entry, &outarg);
836 }
837 fuse_dir_changed(dir);
838 return 0;
839
840 out_put_forget_req:
841 if (err == -EEXIST)
842 fuse_invalidate_entry(entry);
843 kfree(forget);
844 return err;
845 }
846
847 static int fuse_mknod(struct mnt_idmap *idmap, struct inode *dir,
848 struct dentry *entry, umode_t mode, dev_t rdev)
849 {
850 struct fuse_mknod_in inarg;
851 struct fuse_mount *fm = get_fuse_mount(dir);
852 FUSE_ARGS(args);
853
854 if (!fm->fc->dont_mask)
855 mode &= ~current_umask();
856
857 memset(&inarg, 0, sizeof(inarg));
858 inarg.mode = mode;
859 inarg.rdev = new_encode_dev(rdev);
860 inarg.umask = current_umask();
861 args.opcode = FUSE_MKNOD;
862 args.in_numargs = 2;
863 args.in_args[0].size = sizeof(inarg);
864 args.in_args[0].value = &inarg;
865 args.in_args[1].size = entry->d_name.len + 1;
866 args.in_args[1].value = entry->d_name.name;
867 return create_new_entry(fm, &args, dir, entry, mode);
868 }
869
870 static int fuse_create(struct mnt_idmap *idmap, struct inode *dir,
871 struct dentry *entry, umode_t mode, bool excl)
872 {
873 return fuse_mknod(&nop_mnt_idmap, dir, entry, mode, 0);
874 }
875
876 static int fuse_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
877 struct file *file, umode_t mode)
878 {
879 struct fuse_conn *fc = get_fuse_conn(dir);
880 int err;
881
882 if (fc->no_tmpfile)
883 return -EOPNOTSUPP;
884
885 err = fuse_create_open(dir, file->f_path.dentry, file, file->f_flags, mode, FUSE_TMPFILE);
886 if (err == -ENOSYS) {
887 fc->no_tmpfile = 1;
888 err = -EOPNOTSUPP;
889 }
890 return err;
891 }
892
893 static int fuse_mkdir(struct mnt_idmap *idmap, struct inode *dir,
894 struct dentry *entry, umode_t mode)
895 {
896 struct fuse_mkdir_in inarg;
897 struct fuse_mount *fm = get_fuse_mount(dir);
898 FUSE_ARGS(args);
899
900 if (!fm->fc->dont_mask)
901 mode &= ~current_umask();
902
903 memset(&inarg, 0, sizeof(inarg));
904 inarg.mode = mode;
905 inarg.umask = current_umask();
906 args.opcode = FUSE_MKDIR;
907 args.in_numargs = 2;
908 args.in_args[0].size = sizeof(inarg);
909 args.in_args[0].value = &inarg;
910 args.in_args[1].size = entry->d_name.len + 1;
911 args.in_args[1].value = entry->d_name.name;
912 return create_new_entry(fm, &args, dir, entry, S_IFDIR);
913 }
914
915 static int fuse_symlink(struct mnt_idmap *idmap, struct inode *dir,
916 struct dentry *entry, const char *link)
917 {
918 struct fuse_mount *fm = get_fuse_mount(dir);
919 unsigned len = strlen(link) + 1;
920 FUSE_ARGS(args);
921
922 args.opcode = FUSE_SYMLINK;
923 args.in_numargs = 2;
924 args.in_args[0].size = entry->d_name.len + 1;
925 args.in_args[0].value = entry->d_name.name;
926 args.in_args[1].size = len;
927 args.in_args[1].value = link;
928 return create_new_entry(fm, &args, dir, entry, S_IFLNK);
929 }
930
931 void fuse_flush_time_update(struct inode *inode)
932 {
933 int err = sync_inode_metadata(inode, 1);
934
935 mapping_set_error(inode->i_mapping, err);
936 }
937
938 static void fuse_update_ctime_in_cache(struct inode *inode)
939 {
940 if (!IS_NOCMTIME(inode)) {
941 inode_set_ctime_current(inode);
942 mark_inode_dirty_sync(inode);
943 fuse_flush_time_update(inode);
944 }
945 }
946
947 void fuse_update_ctime(struct inode *inode)
948 {
949 fuse_invalidate_attr_mask(inode, STATX_CTIME);
950 fuse_update_ctime_in_cache(inode);
951 }
952
953 static void fuse_entry_unlinked(struct dentry *entry)
954 {
955 struct inode *inode = d_inode(entry);
956 struct fuse_conn *fc = get_fuse_conn(inode);
957 struct fuse_inode *fi = get_fuse_inode(inode);
958
959 spin_lock(&fi->lock);
960 fi->attr_version = atomic64_inc_return(&fc->attr_version);
961 /*
962 * If i_nlink == 0 then unlink doesn't make sense, yet this can
963 * happen if userspace filesystem is careless. It would be
964 * difficult to enforce correct nlink usage so just ignore this
965 * condition here
966 */
967 if (S_ISDIR(inode->i_mode))
968 clear_nlink(inode);
969 else if (inode->i_nlink > 0)
970 drop_nlink(inode);
971 spin_unlock(&fi->lock);
972 fuse_invalidate_entry_cache(entry);
973 fuse_update_ctime(inode);
974 }
975
976 static int fuse_unlink(struct inode *dir, struct dentry *entry)
977 {
978 int err;
979 struct fuse_mount *fm = get_fuse_mount(dir);
980 FUSE_ARGS(args);
981
982 if (fuse_is_bad(dir))
983 return -EIO;
984
985 args.opcode = FUSE_UNLINK;
986 args.nodeid = get_node_id(dir);
987 args.in_numargs = 1;
988 args.in_args[0].size = entry->d_name.len + 1;
989 args.in_args[0].value = entry->d_name.name;
990 err = fuse_simple_request(fm, &args);
991 if (!err) {
992 fuse_dir_changed(dir);
993 fuse_entry_unlinked(entry);
994 } else if (err == -EINTR || err == -ENOENT)
995 fuse_invalidate_entry(entry);
996 return err;
997 }
998
999 static int fuse_rmdir(struct inode *dir, struct dentry *entry)
1000 {
1001 int err;
1002 struct fuse_mount *fm = get_fuse_mount(dir);
1003 FUSE_ARGS(args);
1004
1005 if (fuse_is_bad(dir))
1006 return -EIO;
1007
1008 args.opcode = FUSE_RMDIR;
1009 args.nodeid = get_node_id(dir);
1010 args.in_numargs = 1;
1011 args.in_args[0].size = entry->d_name.len + 1;
1012 args.in_args[0].value = entry->d_name.name;
1013 err = fuse_simple_request(fm, &args);
1014 if (!err) {
1015 fuse_dir_changed(dir);
1016 fuse_entry_unlinked(entry);
1017 } else if (err == -EINTR || err == -ENOENT)
1018 fuse_invalidate_entry(entry);
1019 return err;
1020 }
1021
1022 static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
1023 struct inode *newdir, struct dentry *newent,
1024 unsigned int flags, int opcode, size_t argsize)
1025 {
1026 int err;
1027 struct fuse_rename2_in inarg;
1028 struct fuse_mount *fm = get_fuse_mount(olddir);
1029 FUSE_ARGS(args);
1030
1031 memset(&inarg, 0, argsize);
1032 inarg.newdir = get_node_id(newdir);
1033 inarg.flags = flags;
1034 args.opcode = opcode;
1035 args.nodeid = get_node_id(olddir);
1036 args.in_numargs = 3;
1037 args.in_args[0].size = argsize;
1038 args.in_args[0].value = &inarg;
1039 args.in_args[1].size = oldent->d_name.len + 1;
1040 args.in_args[1].value = oldent->d_name.name;
1041 args.in_args[2].size = newent->d_name.len + 1;
1042 args.in_args[2].value = newent->d_name.name;
1043 err = fuse_simple_request(fm, &args);
1044 if (!err) {
1045 /* ctime changes */
1046 fuse_update_ctime(d_inode(oldent));
1047
1048 if (flags & RENAME_EXCHANGE)
1049 fuse_update_ctime(d_inode(newent));
1050
1051 fuse_dir_changed(olddir);
1052 if (olddir != newdir)
1053 fuse_dir_changed(newdir);
1054
1055 /* newent will end up negative */
1056 if (!(flags & RENAME_EXCHANGE) && d_really_is_positive(newent))
1057 fuse_entry_unlinked(newent);
1058 } else if (err == -EINTR || err == -ENOENT) {
1059 /* If request was interrupted, DEITY only knows if the
1060 rename actually took place. If the invalidation
1061 fails (e.g. some process has CWD under the renamed
1062 directory), then there can be inconsistency between
1063 the dcache and the real filesystem. Tough luck. */
1064 fuse_invalidate_entry(oldent);
1065 if (d_really_is_positive(newent))
1066 fuse_invalidate_entry(newent);
1067 }
1068
1069 return err;
1070 }
1071
1072 static int fuse_rename2(struct mnt_idmap *idmap, struct inode *olddir,
1073 struct dentry *oldent, struct inode *newdir,
1074 struct dentry *newent, unsigned int flags)
1075 {
1076 struct fuse_conn *fc = get_fuse_conn(olddir);
1077 int err;
1078
1079 if (fuse_is_bad(olddir))
1080 return -EIO;
1081
1082 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
1083 return -EINVAL;
1084
1085 if (flags) {
1086 if (fc->no_rename2 || fc->minor < 23)
1087 return -EINVAL;
1088
1089 err = fuse_rename_common(olddir, oldent, newdir, newent, flags,
1090 FUSE_RENAME2,
1091 sizeof(struct fuse_rename2_in));
1092 if (err == -ENOSYS) {
1093 fc->no_rename2 = 1;
1094 err = -EINVAL;
1095 }
1096 } else {
1097 err = fuse_rename_common(olddir, oldent, newdir, newent, 0,
1098 FUSE_RENAME,
1099 sizeof(struct fuse_rename_in));
1100 }
1101
1102 return err;
1103 }
1104
1105 static int fuse_link(struct dentry *entry, struct inode *newdir,
1106 struct dentry *newent)
1107 {
1108 int err;
1109 struct fuse_link_in inarg;
1110 struct inode *inode = d_inode(entry);
1111 struct fuse_mount *fm = get_fuse_mount(inode);
1112 FUSE_ARGS(args);
1113
1114 memset(&inarg, 0, sizeof(inarg));
1115 inarg.oldnodeid = get_node_id(inode);
1116 args.opcode = FUSE_LINK;
1117 args.in_numargs = 2;
1118 args.in_args[0].size = sizeof(inarg);
1119 args.in_args[0].value = &inarg;
1120 args.in_args[1].size = newent->d_name.len + 1;
1121 args.in_args[1].value = newent->d_name.name;
1122 err = create_new_entry(fm, &args, newdir, newent, inode->i_mode);
1123 if (!err)
1124 fuse_update_ctime_in_cache(inode);
1125 else if (err == -EINTR)
1126 fuse_invalidate_attr(inode);
1127
1128 return err;
1129 }
1130
1131 static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
1132 struct kstat *stat)
1133 {
1134 unsigned int blkbits;
1135 struct fuse_conn *fc = get_fuse_conn(inode);
1136
1137 stat->dev = inode->i_sb->s_dev;
1138 stat->ino = attr->ino;
1139 stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
1140 stat->nlink = attr->nlink;
1141 stat->uid = make_kuid(fc->user_ns, attr->uid);
1142 stat->gid = make_kgid(fc->user_ns, attr->gid);
1143 stat->rdev = inode->i_rdev;
1144 stat->atime.tv_sec = attr->atime;
1145 stat->atime.tv_nsec = attr->atimensec;
1146 stat->mtime.tv_sec = attr->mtime;
1147 stat->mtime.tv_nsec = attr->mtimensec;
1148 stat->ctime.tv_sec = attr->ctime;
1149 stat->ctime.tv_nsec = attr->ctimensec;
1150 stat->size = attr->size;
1151 stat->blocks = attr->blocks;
1152
1153 if (attr->blksize != 0)
1154 blkbits = ilog2(attr->blksize);
1155 else
1156 blkbits = inode->i_sb->s_blocksize_bits;
1157
1158 stat->blksize = 1 << blkbits;
1159 }
1160
1161 static void fuse_statx_to_attr(struct fuse_statx *sx, struct fuse_attr *attr)
1162 {
1163 memset(attr, 0, sizeof(*attr));
1164 attr->ino = sx->ino;
1165 attr->size = sx->size;
1166 attr->blocks = sx->blocks;
1167 attr->atime = sx->atime.tv_sec;
1168 attr->mtime = sx->mtime.tv_sec;
1169 attr->ctime = sx->ctime.tv_sec;
1170 attr->atimensec = sx->atime.tv_nsec;
1171 attr->mtimensec = sx->mtime.tv_nsec;
1172 attr->ctimensec = sx->ctime.tv_nsec;
1173 attr->mode = sx->mode;
1174 attr->nlink = sx->nlink;
1175 attr->uid = sx->uid;
1176 attr->gid = sx->gid;
1177 attr->rdev = new_encode_dev(MKDEV(sx->rdev_major, sx->rdev_minor));
1178 attr->blksize = sx->blksize;
1179 }
1180
1181 static int fuse_do_statx(struct inode *inode, struct file *file,
1182 struct kstat *stat)
1183 {
1184 int err;
1185 struct fuse_attr attr;
1186 struct fuse_statx *sx;
1187 struct fuse_statx_in inarg;
1188 struct fuse_statx_out outarg;
1189 struct fuse_mount *fm = get_fuse_mount(inode);
1190 u64 attr_version = fuse_get_attr_version(fm->fc);
1191 FUSE_ARGS(args);
1192
1193 memset(&inarg, 0, sizeof(inarg));
1194 memset(&outarg, 0, sizeof(outarg));
1195 /* Directories have separate file-handle space */
1196 if (file && S_ISREG(inode->i_mode)) {
1197 struct fuse_file *ff = file->private_data;
1198
1199 inarg.getattr_flags |= FUSE_GETATTR_FH;
1200 inarg.fh = ff->fh;
1201 }
1202 /* For now leave sync hints as the default, request all stats. */
1203 inarg.sx_flags = 0;
1204 inarg.sx_mask = STATX_BASIC_STATS | STATX_BTIME;
1205 args.opcode = FUSE_STATX;
1206 args.nodeid = get_node_id(inode);
1207 args.in_numargs = 1;
1208 args.in_args[0].size = sizeof(inarg);
1209 args.in_args[0].value = &inarg;
1210 args.out_numargs = 1;
1211 args.out_args[0].size = sizeof(outarg);
1212 args.out_args[0].value = &outarg;
1213 err = fuse_simple_request(fm, &args);
1214 if (err)
1215 return err;
1216
1217 sx = &outarg.stat;
1218 if (((sx->mask & STATX_SIZE) && !fuse_valid_size(sx->size)) ||
1219 ((sx->mask & STATX_TYPE) && (!fuse_valid_type(sx->mode) ||
1220 inode_wrong_type(inode, sx->mode)))) {
1221 fuse_make_bad(inode);
1222 return -EIO;
1223 }
1224
1225 fuse_statx_to_attr(&outarg.stat, &attr);
1226 if ((sx->mask & STATX_BASIC_STATS) == STATX_BASIC_STATS) {
1227 fuse_change_attributes(inode, &attr, &outarg.stat,
1228 ATTR_TIMEOUT(&outarg), attr_version);
1229 }
1230
1231 if (stat) {
1232 stat->result_mask = sx->mask & (STATX_BASIC_STATS | STATX_BTIME);
1233 stat->btime.tv_sec = sx->btime.tv_sec;
1234 stat->btime.tv_nsec = min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1);
1235 fuse_fillattr(inode, &attr, stat);
1236 stat->result_mask |= STATX_TYPE;
1237 }
1238
1239 return 0;
1240 }
1241
1242 static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
1243 struct file *file)
1244 {
1245 int err;
1246 struct fuse_getattr_in inarg;
1247 struct fuse_attr_out outarg;
1248 struct fuse_mount *fm = get_fuse_mount(inode);
1249 FUSE_ARGS(args);
1250 u64 attr_version;
1251
1252 attr_version = fuse_get_attr_version(fm->fc);
1253
1254 memset(&inarg, 0, sizeof(inarg));
1255 memset(&outarg, 0, sizeof(outarg));
1256 /* Directories have separate file-handle space */
1257 if (file && S_ISREG(inode->i_mode)) {
1258 struct fuse_file *ff = file->private_data;
1259
1260 inarg.getattr_flags |= FUSE_GETATTR_FH;
1261 inarg.fh = ff->fh;
1262 }
1263 args.opcode = FUSE_GETATTR;
1264 args.nodeid = get_node_id(inode);
1265 args.in_numargs = 1;
1266 args.in_args[0].size = sizeof(inarg);
1267 args.in_args[0].value = &inarg;
1268 args.out_numargs = 1;
1269 args.out_args[0].size = sizeof(outarg);
1270 args.out_args[0].value = &outarg;
1271 err = fuse_simple_request(fm, &args);
1272 if (!err) {
1273 if (fuse_invalid_attr(&outarg.attr) ||
1274 inode_wrong_type(inode, outarg.attr.mode)) {
1275 fuse_make_bad(inode);
1276 err = -EIO;
1277 } else {
1278 fuse_change_attributes(inode, &outarg.attr, NULL,
1279 ATTR_TIMEOUT(&outarg),
1280 attr_version);
1281 if (stat)
1282 fuse_fillattr(inode, &outarg.attr, stat);
1283 }
1284 }
1285 return err;
1286 }
1287
1288 static int fuse_update_get_attr(struct inode *inode, struct file *file,
1289 struct kstat *stat, u32 request_mask,
1290 unsigned int flags)
1291 {
1292 struct fuse_inode *fi = get_fuse_inode(inode);
1293 struct fuse_conn *fc = get_fuse_conn(inode);
1294 int err = 0;
1295 bool sync;
1296 u32 inval_mask = READ_ONCE(fi->inval_mask);
1297 u32 cache_mask = fuse_get_cache_mask(inode);
1298
1299
1300 /* FUSE only supports basic stats and possibly btime */
1301 request_mask &= STATX_BASIC_STATS | STATX_BTIME;
1302 retry:
1303 if (fc->no_statx)
1304 request_mask &= STATX_BASIC_STATS;
1305
1306 if (!request_mask)
1307 sync = false;
1308 else if (flags & AT_STATX_FORCE_SYNC)
1309 sync = true;
1310 else if (flags & AT_STATX_DONT_SYNC)
1311 sync = false;
1312 else if (request_mask & inval_mask & ~cache_mask)
1313 sync = true;
1314 else
1315 sync = time_before64(fi->i_time, get_jiffies_64());
1316
1317 if (sync) {
1318 forget_all_cached_acls(inode);
1319 /* Try statx if BTIME is requested */
1320 if (!fc->no_statx && (request_mask & ~STATX_BASIC_STATS)) {
1321 err = fuse_do_statx(inode, file, stat);
1322 if (err == -ENOSYS) {
1323 fc->no_statx = 1;
1324 err = 0;
1325 goto retry;
1326 }
1327 } else {
1328 err = fuse_do_getattr(inode, stat, file);
1329 }
1330 } else if (stat) {
1331 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
1332 stat->mode = fi->orig_i_mode;
1333 stat->ino = fi->orig_ino;
1334 if (test_bit(FUSE_I_BTIME, &fi->state)) {
1335 stat->btime = fi->i_btime;
1336 stat->result_mask |= STATX_BTIME;
1337 }
1338 }
1339
1340 return err;
1341 }
1342
1343 int fuse_update_attributes(struct inode *inode, struct file *file, u32 mask)
1344 {
1345 return fuse_update_get_attr(inode, file, NULL, mask, 0);
1346 }
1347
1348 int fuse_reverse_inval_entry(struct fuse_conn *fc, u64 parent_nodeid,
1349 u64 child_nodeid, struct qstr *name, u32 flags)
1350 {
1351 int err = -ENOTDIR;
1352 struct inode *parent;
1353 struct dentry *dir;
1354 struct dentry *entry;
1355
1356 parent = fuse_ilookup(fc, parent_nodeid, NULL);
1357 if (!parent)
1358 return -ENOENT;
1359
1360 inode_lock_nested(parent, I_MUTEX_PARENT);
1361 if (!S_ISDIR(parent->i_mode))
1362 goto unlock;
1363
1364 err = -ENOENT;
1365 dir = d_find_alias(parent);
1366 if (!dir)
1367 goto unlock;
1368
1369 name->hash = full_name_hash(dir, name->name, name->len);
1370 entry = d_lookup(dir, name);
1371 dput(dir);
1372 if (!entry)
1373 goto unlock;
1374
1375 fuse_dir_changed(parent);
1376 if (!(flags & FUSE_EXPIRE_ONLY))
1377 d_invalidate(entry);
1378 fuse_invalidate_entry_cache(entry);
1379
1380 if (child_nodeid != 0 && d_really_is_positive(entry)) {
1381 inode_lock(d_inode(entry));
1382 if (get_node_id(d_inode(entry)) != child_nodeid) {
1383 err = -ENOENT;
1384 goto badentry;
1385 }
1386 if (d_mountpoint(entry)) {
1387 err = -EBUSY;
1388 goto badentry;
1389 }
1390 if (d_is_dir(entry)) {
1391 shrink_dcache_parent(entry);
1392 if (!simple_empty(entry)) {
1393 err = -ENOTEMPTY;
1394 goto badentry;
1395 }
1396 d_inode(entry)->i_flags |= S_DEAD;
1397 }
1398 dont_mount(entry);
1399 clear_nlink(d_inode(entry));
1400 err = 0;
1401 badentry:
1402 inode_unlock(d_inode(entry));
1403 if (!err)
1404 d_delete(entry);
1405 } else {
1406 err = 0;
1407 }
1408 dput(entry);
1409
1410 unlock:
1411 inode_unlock(parent);
1412 iput(parent);
1413 return err;
1414 }
1415
1416 static inline bool fuse_permissible_uidgid(struct fuse_conn *fc)
1417 {
1418 const struct cred *cred = current_cred();
1419
1420 return (uid_eq(cred->euid, fc->user_id) &&
1421 uid_eq(cred->suid, fc->user_id) &&
1422 uid_eq(cred->uid, fc->user_id) &&
1423 gid_eq(cred->egid, fc->group_id) &&
1424 gid_eq(cred->sgid, fc->group_id) &&
1425 gid_eq(cred->gid, fc->group_id));
1426 }
1427
1428 /*
1429 * Calling into a user-controlled filesystem gives the filesystem
1430 * daemon ptrace-like capabilities over the current process. This
1431 * means, that the filesystem daemon is able to record the exact
1432 * filesystem operations performed, and can also control the behavior
1433 * of the requester process in otherwise impossible ways. For example
1434 * it can delay the operation for arbitrary length of time allowing
1435 * DoS against the requester.
1436 *
1437 * For this reason only those processes can call into the filesystem,
1438 * for which the owner of the mount has ptrace privilege. This
1439 * excludes processes started by other users, suid or sgid processes.
1440 */
1441 bool fuse_allow_current_process(struct fuse_conn *fc)
1442 {
1443 bool allow;
1444
1445 if (fc->allow_other)
1446 allow = current_in_userns(fc->user_ns);
1447 else
1448 allow = fuse_permissible_uidgid(fc);
1449
1450 if (!allow && allow_sys_admin_access && capable(CAP_SYS_ADMIN))
1451 allow = true;
1452
1453 return allow;
1454 }
1455
1456 static int fuse_access(struct inode *inode, int mask)
1457 {
1458 struct fuse_mount *fm = get_fuse_mount(inode);
1459 FUSE_ARGS(args);
1460 struct fuse_access_in inarg;
1461 int err;
1462
1463 BUG_ON(mask & MAY_NOT_BLOCK);
1464
1465 if (fm->fc->no_access)
1466 return 0;
1467
1468 memset(&inarg, 0, sizeof(inarg));
1469 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1470 args.opcode = FUSE_ACCESS;
1471 args.nodeid = get_node_id(inode);
1472 args.in_numargs = 1;
1473 args.in_args[0].size = sizeof(inarg);
1474 args.in_args[0].value = &inarg;
1475 err = fuse_simple_request(fm, &args);
1476 if (err == -ENOSYS) {
1477 fm->fc->no_access = 1;
1478 err = 0;
1479 }
1480 return err;
1481 }
1482
1483 static int fuse_perm_getattr(struct inode *inode, int mask)
1484 {
1485 if (mask & MAY_NOT_BLOCK)
1486 return -ECHILD;
1487
1488 forget_all_cached_acls(inode);
1489 return fuse_do_getattr(inode, NULL, NULL);
1490 }
1491
1492 /*
1493 * Check permission. The two basic access models of FUSE are:
1494 *
1495 * 1) Local access checking ('default_permissions' mount option) based
1496 * on file mode. This is the plain old disk filesystem permission
1497 * model.
1498 *
1499 * 2) "Remote" access checking, where server is responsible for
1500 * checking permission in each inode operation. An exception to this
1501 * is if ->permission() was invoked from sys_access() in which case an
1502 * access request is sent. Execute permission is still checked
1503 * locally based on file mode.
1504 */
1505 static int fuse_permission(struct mnt_idmap *idmap,
1506 struct inode *inode, int mask)
1507 {
1508 struct fuse_conn *fc = get_fuse_conn(inode);
1509 bool refreshed = false;
1510 int err = 0;
1511
1512 if (fuse_is_bad(inode))
1513 return -EIO;
1514
1515 if (!fuse_allow_current_process(fc))
1516 return -EACCES;
1517
1518 /*
1519 * If attributes are needed, refresh them before proceeding
1520 */
1521 if (fc->default_permissions ||
1522 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1523 struct fuse_inode *fi = get_fuse_inode(inode);
1524 u32 perm_mask = STATX_MODE | STATX_UID | STATX_GID;
1525
1526 if (perm_mask & READ_ONCE(fi->inval_mask) ||
1527 time_before64(fi->i_time, get_jiffies_64())) {
1528 refreshed = true;
1529
1530 err = fuse_perm_getattr(inode, mask);
1531 if (err)
1532 return err;
1533 }
1534 }
1535
1536 if (fc->default_permissions) {
1537 err = generic_permission(&nop_mnt_idmap, inode, mask);
1538
1539 /* If permission is denied, try to refresh file
1540 attributes. This is also needed, because the root
1541 node will at first have no permissions */
1542 if (err == -EACCES && !refreshed) {
1543 err = fuse_perm_getattr(inode, mask);
1544 if (!err)
1545 err = generic_permission(&nop_mnt_idmap,
1546 inode, mask);
1547 }
1548
1549 /* Note: the opposite of the above test does not
1550 exist. So if permissions are revoked this won't be
1551 noticed immediately, only after the attribute
1552 timeout has expired */
1553 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1554 err = fuse_access(inode, mask);
1555 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1556 if (!(inode->i_mode & S_IXUGO)) {
1557 if (refreshed)
1558 return -EACCES;
1559
1560 err = fuse_perm_getattr(inode, mask);
1561 if (!err && !(inode->i_mode & S_IXUGO))
1562 return -EACCES;
1563 }
1564 }
1565 return err;
1566 }
1567
1568 static int fuse_readlink_page(struct inode *inode, struct page *page)
1569 {
1570 struct fuse_mount *fm = get_fuse_mount(inode);
1571 struct fuse_page_desc desc = { .length = PAGE_SIZE - 1 };
1572 struct fuse_args_pages ap = {
1573 .num_pages = 1,
1574 .pages = &page,
1575 .descs = &desc,
1576 };
1577 char *link;
1578 ssize_t res;
1579
1580 ap.args.opcode = FUSE_READLINK;
1581 ap.args.nodeid = get_node_id(inode);
1582 ap.args.out_pages = true;
1583 ap.args.out_argvar = true;
1584 ap.args.page_zeroing = true;
1585 ap.args.out_numargs = 1;
1586 ap.args.out_args[0].size = desc.length;
1587 res = fuse_simple_request(fm, &ap.args);
1588
1589 fuse_invalidate_atime(inode);
1590
1591 if (res < 0)
1592 return res;
1593
1594 if (WARN_ON(res >= PAGE_SIZE))
1595 return -EIO;
1596
1597 link = page_address(page);
1598 link[res] = '\0';
1599
1600 return 0;
1601 }
1602
1603 static const char *fuse_get_link(struct dentry *dentry, struct inode *inode,
1604 struct delayed_call *callback)
1605 {
1606 struct fuse_conn *fc = get_fuse_conn(inode);
1607 struct page *page;
1608 int err;
1609
1610 err = -EIO;
1611 if (fuse_is_bad(inode))
1612 goto out_err;
1613
1614 if (fc->cache_symlinks)
1615 return page_get_link(dentry, inode, callback);
1616
1617 err = -ECHILD;
1618 if (!dentry)
1619 goto out_err;
1620
1621 page = alloc_page(GFP_KERNEL);
1622 err = -ENOMEM;
1623 if (!page)
1624 goto out_err;
1625
1626 err = fuse_readlink_page(inode, page);
1627 if (err) {
1628 __free_page(page);
1629 goto out_err;
1630 }
1631
1632 set_delayed_call(callback, page_put_link, page);
1633
1634 return page_address(page);
1635
1636 out_err:
1637 return ERR_PTR(err);
1638 }
1639
1640 static int fuse_dir_open(struct inode *inode, struct file *file)
1641 {
1642 struct fuse_mount *fm = get_fuse_mount(inode);
1643 int err;
1644
1645 if (fuse_is_bad(inode))
1646 return -EIO;
1647
1648 err = generic_file_open(inode, file);
1649 if (err)
1650 return err;
1651
1652 err = fuse_do_open(fm, get_node_id(inode), file, true);
1653 if (!err) {
1654 struct fuse_file *ff = file->private_data;
1655
1656 /*
1657 * Keep handling FOPEN_STREAM and FOPEN_NONSEEKABLE for
1658 * directories for backward compatibility, though it's unlikely
1659 * to be useful.
1660 */
1661 if (ff->open_flags & (FOPEN_STREAM | FOPEN_NONSEEKABLE))
1662 nonseekable_open(inode, file);
1663 }
1664
1665 return err;
1666 }
1667
1668 static int fuse_dir_release(struct inode *inode, struct file *file)
1669 {
1670 fuse_release_common(file, true);
1671
1672 return 0;
1673 }
1674
1675 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1676 int datasync)
1677 {
1678 struct inode *inode = file->f_mapping->host;
1679 struct fuse_conn *fc = get_fuse_conn(inode);
1680 int err;
1681
1682 if (fuse_is_bad(inode))
1683 return -EIO;
1684
1685 if (fc->no_fsyncdir)
1686 return 0;
1687
1688 inode_lock(inode);
1689 err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNCDIR);
1690 if (err == -ENOSYS) {
1691 fc->no_fsyncdir = 1;
1692 err = 0;
1693 }
1694 inode_unlock(inode);
1695
1696 return err;
1697 }
1698
1699 static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1700 unsigned long arg)
1701 {
1702 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1703
1704 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1705 if (fc->minor < 18)
1706 return -ENOTTY;
1707
1708 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1709 }
1710
1711 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1712 unsigned long arg)
1713 {
1714 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1715
1716 if (fc->minor < 18)
1717 return -ENOTTY;
1718
1719 return fuse_ioctl_common(file, cmd, arg,
1720 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1721 }
1722
1723 static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
1724 {
1725 /* Always update if mtime is explicitly set */
1726 if (ivalid & ATTR_MTIME_SET)
1727 return true;
1728
1729 /* Or if kernel i_mtime is the official one */
1730 if (trust_local_mtime)
1731 return true;
1732
1733 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1734 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1735 return false;
1736
1737 /* In all other cases update */
1738 return true;
1739 }
1740
1741 static void iattr_to_fattr(struct fuse_conn *fc, struct iattr *iattr,
1742 struct fuse_setattr_in *arg, bool trust_local_cmtime)
1743 {
1744 unsigned ivalid = iattr->ia_valid;
1745
1746 if (ivalid & ATTR_MODE)
1747 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
1748 if (ivalid & ATTR_UID)
1749 arg->valid |= FATTR_UID, arg->uid = from_kuid(fc->user_ns, iattr->ia_uid);
1750 if (ivalid & ATTR_GID)
1751 arg->valid |= FATTR_GID, arg->gid = from_kgid(fc->user_ns, iattr->ia_gid);
1752 if (ivalid & ATTR_SIZE)
1753 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
1754 if (ivalid & ATTR_ATIME) {
1755 arg->valid |= FATTR_ATIME;
1756 arg->atime = iattr->ia_atime.tv_sec;
1757 arg->atimensec = iattr->ia_atime.tv_nsec;
1758 if (!(ivalid & ATTR_ATIME_SET))
1759 arg->valid |= FATTR_ATIME_NOW;
1760 }
1761 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid, trust_local_cmtime)) {
1762 arg->valid |= FATTR_MTIME;
1763 arg->mtime = iattr->ia_mtime.tv_sec;
1764 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1765 if (!(ivalid & ATTR_MTIME_SET) && !trust_local_cmtime)
1766 arg->valid |= FATTR_MTIME_NOW;
1767 }
1768 if ((ivalid & ATTR_CTIME) && trust_local_cmtime) {
1769 arg->valid |= FATTR_CTIME;
1770 arg->ctime = iattr->ia_ctime.tv_sec;
1771 arg->ctimensec = iattr->ia_ctime.tv_nsec;
1772 }
1773 }
1774
1775 /*
1776 * Prevent concurrent writepages on inode
1777 *
1778 * This is done by adding a negative bias to the inode write counter
1779 * and waiting for all pending writes to finish.
1780 */
1781 void fuse_set_nowrite(struct inode *inode)
1782 {
1783 struct fuse_inode *fi = get_fuse_inode(inode);
1784
1785 BUG_ON(!inode_is_locked(inode));
1786
1787 spin_lock(&fi->lock);
1788 BUG_ON(fi->writectr < 0);
1789 fi->writectr += FUSE_NOWRITE;
1790 spin_unlock(&fi->lock);
1791 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1792 }
1793
1794 /*
1795 * Allow writepages on inode
1796 *
1797 * Remove the bias from the writecounter and send any queued
1798 * writepages.
1799 */
1800 static void __fuse_release_nowrite(struct inode *inode)
1801 {
1802 struct fuse_inode *fi = get_fuse_inode(inode);
1803
1804 BUG_ON(fi->writectr != FUSE_NOWRITE);
1805 fi->writectr = 0;
1806 fuse_flush_writepages(inode);
1807 }
1808
1809 void fuse_release_nowrite(struct inode *inode)
1810 {
1811 struct fuse_inode *fi = get_fuse_inode(inode);
1812
1813 spin_lock(&fi->lock);
1814 __fuse_release_nowrite(inode);
1815 spin_unlock(&fi->lock);
1816 }
1817
1818 static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_args *args,
1819 struct inode *inode,
1820 struct fuse_setattr_in *inarg_p,
1821 struct fuse_attr_out *outarg_p)
1822 {
1823 args->opcode = FUSE_SETATTR;
1824 args->nodeid = get_node_id(inode);
1825 args->in_numargs = 1;
1826 args->in_args[0].size = sizeof(*inarg_p);
1827 args->in_args[0].value = inarg_p;
1828 args->out_numargs = 1;
1829 args->out_args[0].size = sizeof(*outarg_p);
1830 args->out_args[0].value = outarg_p;
1831 }
1832
1833 /*
1834 * Flush inode->i_mtime to the server
1835 */
1836 int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
1837 {
1838 struct fuse_mount *fm = get_fuse_mount(inode);
1839 FUSE_ARGS(args);
1840 struct fuse_setattr_in inarg;
1841 struct fuse_attr_out outarg;
1842
1843 memset(&inarg, 0, sizeof(inarg));
1844 memset(&outarg, 0, sizeof(outarg));
1845
1846 inarg.valid = FATTR_MTIME;
1847 inarg.mtime = inode_get_mtime_sec(inode);
1848 inarg.mtimensec = inode_get_mtime_nsec(inode);
1849 if (fm->fc->minor >= 23) {
1850 inarg.valid |= FATTR_CTIME;
1851 inarg.ctime = inode_get_ctime_sec(inode);
1852 inarg.ctimensec = inode_get_ctime_nsec(inode);
1853 }
1854 if (ff) {
1855 inarg.valid |= FATTR_FH;
1856 inarg.fh = ff->fh;
1857 }
1858 fuse_setattr_fill(fm->fc, &args, inode, &inarg, &outarg);
1859
1860 return fuse_simple_request(fm, &args);
1861 }
1862
1863 /*
1864 * Set attributes, and at the same time refresh them.
1865 *
1866 * Truncation is slightly complicated, because the 'truncate' request
1867 * may fail, in which case we don't want to touch the mapping.
1868 * vmtruncate() doesn't allow for this case, so do the rlimit checking
1869 * and the actual truncation by hand.
1870 */
1871 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
1872 struct file *file)
1873 {
1874 struct inode *inode = d_inode(dentry);
1875 struct fuse_mount *fm = get_fuse_mount(inode);
1876 struct fuse_conn *fc = fm->fc;
1877 struct fuse_inode *fi = get_fuse_inode(inode);
1878 struct address_space *mapping = inode->i_mapping;
1879 FUSE_ARGS(args);
1880 struct fuse_setattr_in inarg;
1881 struct fuse_attr_out outarg;
1882 bool is_truncate = false;
1883 bool is_wb = fc->writeback_cache && S_ISREG(inode->i_mode);
1884 loff_t oldsize;
1885 int err;
1886 bool trust_local_cmtime = is_wb;
1887 bool fault_blocked = false;
1888
1889 if (!fc->default_permissions)
1890 attr->ia_valid |= ATTR_FORCE;
1891
1892 err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
1893 if (err)
1894 return err;
1895
1896 if (attr->ia_valid & ATTR_SIZE) {
1897 if (WARN_ON(!S_ISREG(inode->i_mode)))
1898 return -EIO;
1899 is_truncate = true;
1900 }
1901
1902 if (FUSE_IS_DAX(inode) && is_truncate) {
1903 filemap_invalidate_lock(mapping);
1904 fault_blocked = true;
1905 err = fuse_dax_break_layouts(inode, 0, 0);
1906 if (err) {
1907 filemap_invalidate_unlock(mapping);
1908 return err;
1909 }
1910 }
1911
1912 if (attr->ia_valid & ATTR_OPEN) {
1913 /* This is coming from open(..., ... | O_TRUNC); */
1914 WARN_ON(!(attr->ia_valid & ATTR_SIZE));
1915 WARN_ON(attr->ia_size != 0);
1916 if (fc->atomic_o_trunc) {
1917 /*
1918 * No need to send request to userspace, since actual
1919 * truncation has already been done by OPEN. But still
1920 * need to truncate page cache.
1921 */
1922 i_size_write(inode, 0);
1923 truncate_pagecache(inode, 0);
1924 goto out;
1925 }
1926 file = NULL;
1927 }
1928
1929 /* Flush dirty data/metadata before non-truncate SETATTR */
1930 if (is_wb &&
1931 attr->ia_valid &
1932 (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_MTIME_SET |
1933 ATTR_TIMES_SET)) {
1934 err = write_inode_now(inode, true);
1935 if (err)
1936 return err;
1937
1938 fuse_set_nowrite(inode);
1939 fuse_release_nowrite(inode);
1940 }
1941
1942 if (is_truncate) {
1943 fuse_set_nowrite(inode);
1944 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1945 if (trust_local_cmtime && attr->ia_size != inode->i_size)
1946 attr->ia_valid |= ATTR_MTIME | ATTR_CTIME;
1947 }
1948
1949 memset(&inarg, 0, sizeof(inarg));
1950 memset(&outarg, 0, sizeof(outarg));
1951 iattr_to_fattr(fc, attr, &inarg, trust_local_cmtime);
1952 if (file) {
1953 struct fuse_file *ff = file->private_data;
1954 inarg.valid |= FATTR_FH;
1955 inarg.fh = ff->fh;
1956 }
1957
1958 /* Kill suid/sgid for non-directory chown unconditionally */
1959 if (fc->handle_killpriv_v2 && !S_ISDIR(inode->i_mode) &&
1960 attr->ia_valid & (ATTR_UID | ATTR_GID))
1961 inarg.valid |= FATTR_KILL_SUIDGID;
1962
1963 if (attr->ia_valid & ATTR_SIZE) {
1964 /* For mandatory locking in truncate */
1965 inarg.valid |= FATTR_LOCKOWNER;
1966 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1967
1968 /* Kill suid/sgid for truncate only if no CAP_FSETID */
1969 if (fc->handle_killpriv_v2 && !capable(CAP_FSETID))
1970 inarg.valid |= FATTR_KILL_SUIDGID;
1971 }
1972 fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1973 err = fuse_simple_request(fm, &args);
1974 if (err) {
1975 if (err == -EINTR)
1976 fuse_invalidate_attr(inode);
1977 goto error;
1978 }
1979
1980 if (fuse_invalid_attr(&outarg.attr) ||
1981 inode_wrong_type(inode, outarg.attr.mode)) {
1982 fuse_make_bad(inode);
1983 err = -EIO;
1984 goto error;
1985 }
1986
1987 spin_lock(&fi->lock);
1988 /* the kernel maintains i_mtime locally */
1989 if (trust_local_cmtime) {
1990 if (attr->ia_valid & ATTR_MTIME)
1991 inode_set_mtime_to_ts(inode, attr->ia_mtime);
1992 if (attr->ia_valid & ATTR_CTIME)
1993 inode_set_ctime_to_ts(inode, attr->ia_ctime);
1994 /* FIXME: clear I_DIRTY_SYNC? */
1995 }
1996
1997 fuse_change_attributes_common(inode, &outarg.attr, NULL,
1998 ATTR_TIMEOUT(&outarg),
1999 fuse_get_cache_mask(inode));
2000 oldsize = inode->i_size;
2001 /* see the comment in fuse_change_attributes() */
2002 if (!is_wb || is_truncate)
2003 i_size_write(inode, outarg.attr.size);
2004
2005 if (is_truncate) {
2006 /* NOTE: this may release/reacquire fi->lock */
2007 __fuse_release_nowrite(inode);
2008 }
2009 spin_unlock(&fi->lock);
2010
2011 /*
2012 * Only call invalidate_inode_pages2() after removing
2013 * FUSE_NOWRITE, otherwise fuse_launder_folio() would deadlock.
2014 */
2015 if ((is_truncate || !is_wb) &&
2016 S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
2017 truncate_pagecache(inode, outarg.attr.size);
2018 invalidate_inode_pages2(mapping);
2019 }
2020
2021 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
2022 out:
2023 if (fault_blocked)
2024 filemap_invalidate_unlock(mapping);
2025
2026 return 0;
2027
2028 error:
2029 if (is_truncate)
2030 fuse_release_nowrite(inode);
2031
2032 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
2033
2034 if (fault_blocked)
2035 filemap_invalidate_unlock(mapping);
2036 return err;
2037 }
2038
2039 static int fuse_setattr(struct mnt_idmap *idmap, struct dentry *entry,
2040 struct iattr *attr)
2041 {
2042 struct inode *inode = d_inode(entry);
2043 struct fuse_conn *fc = get_fuse_conn(inode);
2044 struct file *file = (attr->ia_valid & ATTR_FILE) ? attr->ia_file : NULL;
2045 int ret;
2046
2047 if (fuse_is_bad(inode))
2048 return -EIO;
2049
2050 if (!fuse_allow_current_process(get_fuse_conn(inode)))
2051 return -EACCES;
2052
2053 if (attr->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) {
2054 attr->ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID |
2055 ATTR_MODE);
2056
2057 /*
2058 * The only sane way to reliably kill suid/sgid is to do it in
2059 * the userspace filesystem
2060 *
2061 * This should be done on write(), truncate() and chown().
2062 */
2063 if (!fc->handle_killpriv && !fc->handle_killpriv_v2) {
2064 /*
2065 * ia_mode calculation may have used stale i_mode.
2066 * Refresh and recalculate.
2067 */
2068 ret = fuse_do_getattr(inode, NULL, file);
2069 if (ret)
2070 return ret;
2071
2072 attr->ia_mode = inode->i_mode;
2073 if (inode->i_mode & S_ISUID) {
2074 attr->ia_valid |= ATTR_MODE;
2075 attr->ia_mode &= ~S_ISUID;
2076 }
2077 if ((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
2078 attr->ia_valid |= ATTR_MODE;
2079 attr->ia_mode &= ~S_ISGID;
2080 }
2081 }
2082 }
2083 if (!attr->ia_valid)
2084 return 0;
2085
2086 ret = fuse_do_setattr(entry, attr, file);
2087 if (!ret) {
2088 /*
2089 * If filesystem supports acls it may have updated acl xattrs in
2090 * the filesystem, so forget cached acls for the inode.
2091 */
2092 if (fc->posix_acl)
2093 forget_all_cached_acls(inode);
2094
2095 /* Directory mode changed, may need to revalidate access */
2096 if (d_is_dir(entry) && (attr->ia_valid & ATTR_MODE))
2097 fuse_invalidate_entry_cache(entry);
2098 }
2099 return ret;
2100 }
2101
2102 static int fuse_getattr(struct mnt_idmap *idmap,
2103 const struct path *path, struct kstat *stat,
2104 u32 request_mask, unsigned int flags)
2105 {
2106 struct inode *inode = d_inode(path->dentry);
2107 struct fuse_conn *fc = get_fuse_conn(inode);
2108
2109 if (fuse_is_bad(inode))
2110 return -EIO;
2111
2112 if (!fuse_allow_current_process(fc)) {
2113 if (!request_mask) {
2114 /*
2115 * If user explicitly requested *nothing* then don't
2116 * error out, but return st_dev only.
2117 */
2118 stat->result_mask = 0;
2119 stat->dev = inode->i_sb->s_dev;
2120 return 0;
2121 }
2122 return -EACCES;
2123 }
2124
2125 return fuse_update_get_attr(inode, NULL, stat, request_mask, flags);
2126 }
2127
2128 static const struct inode_operations fuse_dir_inode_operations = {
2129 .lookup = fuse_lookup,
2130 .mkdir = fuse_mkdir,
2131 .symlink = fuse_symlink,
2132 .unlink = fuse_unlink,
2133 .rmdir = fuse_rmdir,
2134 .rename = fuse_rename2,
2135 .link = fuse_link,
2136 .setattr = fuse_setattr,
2137 .create = fuse_create,
2138 .atomic_open = fuse_atomic_open,
2139 .tmpfile = fuse_tmpfile,
2140 .mknod = fuse_mknod,
2141 .permission = fuse_permission,
2142 .getattr = fuse_getattr,
2143 .listxattr = fuse_listxattr,
2144 .get_inode_acl = fuse_get_inode_acl,
2145 .get_acl = fuse_get_acl,
2146 .set_acl = fuse_set_acl,
2147 .fileattr_get = fuse_fileattr_get,
2148 .fileattr_set = fuse_fileattr_set,
2149 };
2150
2151 static const struct file_operations fuse_dir_operations = {
2152 .llseek = generic_file_llseek,
2153 .read = generic_read_dir,
2154 .iterate_shared = fuse_readdir,
2155 .open = fuse_dir_open,
2156 .release = fuse_dir_release,
2157 .fsync = fuse_dir_fsync,
2158 .unlocked_ioctl = fuse_dir_ioctl,
2159 .compat_ioctl = fuse_dir_compat_ioctl,
2160 };
2161
2162 static const struct inode_operations fuse_common_inode_operations = {
2163 .setattr = fuse_setattr,
2164 .permission = fuse_permission,
2165 .getattr = fuse_getattr,
2166 .listxattr = fuse_listxattr,
2167 .get_inode_acl = fuse_get_inode_acl,
2168 .get_acl = fuse_get_acl,
2169 .set_acl = fuse_set_acl,
2170 .fileattr_get = fuse_fileattr_get,
2171 .fileattr_set = fuse_fileattr_set,
2172 };
2173
2174 static const struct inode_operations fuse_symlink_inode_operations = {
2175 .setattr = fuse_setattr,
2176 .get_link = fuse_get_link,
2177 .getattr = fuse_getattr,
2178 .listxattr = fuse_listxattr,
2179 };
2180
2181 void fuse_init_common(struct inode *inode)
2182 {
2183 inode->i_op = &fuse_common_inode_operations;
2184 }
2185
2186 void fuse_init_dir(struct inode *inode)
2187 {
2188 struct fuse_inode *fi = get_fuse_inode(inode);
2189
2190 inode->i_op = &fuse_dir_inode_operations;
2191 inode->i_fop = &fuse_dir_operations;
2192
2193 spin_lock_init(&fi->rdc.lock);
2194 fi->rdc.cached = false;
2195 fi->rdc.size = 0;
2196 fi->rdc.pos = 0;
2197 fi->rdc.version = 0;
2198 }
2199
2200 static int fuse_symlink_read_folio(struct file *null, struct folio *folio)
2201 {
2202 int err = fuse_readlink_page(folio->mapping->host, &folio->page);
2203
2204 if (!err)
2205 folio_mark_uptodate(folio);
2206
2207 folio_unlock(folio);
2208
2209 return err;
2210 }
2211
2212 static const struct address_space_operations fuse_symlink_aops = {
2213 .read_folio = fuse_symlink_read_folio,
2214 };
2215
2216 void fuse_init_symlink(struct inode *inode)
2217 {
2218 inode->i_op = &fuse_symlink_inode_operations;
2219 inode->i_data.a_ops = &fuse_symlink_aops;
2220 inode_nohighmem(inode);
2221 }
2222
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