1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * File operations used by nfsd. Some of these have been ripped from
4 * other parts of the kernel because they weren't exported, others
5 * are partial duplicates with added or changed functionality.
6 *
7 * Note that several functions dget() the dentry upon which they want
8 * to act, most notably those that create directory entries. Response
9 * dentry's are dput()'d if necessary in the release callback.
10 * So if you notice code paths that apparently fail to dput() the
11 * dentry, don't worry--they have been taken care of.
12 *
13 * Copyright (C) 1995-1999 Olaf Kirch <okir@monad.swb.de>
14 * Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp>
15 */
16
17 #include <linux/fs.h>
18 #include <linux/file.h>
19 #include <linux/splice.h>
20 #include <linux/falloc.h>
21 #include <linux/fcntl.h>
22 #include <linux/namei.h>
23 #include <linux/delay.h>
24 #include <linux/fsnotify.h>
25 #include <linux/posix_acl_xattr.h>
26 #include <linux/xattr.h>
27 #include <linux/jhash.h>
28 #include <linux/ima.h>
29 #include <linux/pagemap.h>
30 #include <linux/slab.h>
31 #include <linux/uaccess.h>
32 #include <linux/exportfs.h>
33 #include <linux/writeback.h>
34 #include <linux/security.h>
35
36 #include "xdr3.h"
37
38 #ifdef CONFIG_NFSD_V4
39 #include "../internal.h"
40 #include "acl.h"
41 #include "idmap.h"
42 #include "xdr4.h"
43 #endif /* CONFIG_NFSD_V4 */
44
45 #include "nfsd.h"
46 #include "vfs.h"
47 #include "filecache.h"
48 #include "trace.h"
49
50 #define NFSDDBG_FACILITY NFSDDBG_FILEOP
51
52 /*
53 * Called from nfsd_lookup and encode_dirent. Check if we have crossed
54 * a mount point.
55 * Returns -EAGAIN or -ETIMEDOUT leaving *dpp and *expp unchanged,
56 * or nfs_ok having possibly changed *dpp and *expp
57 */
58 int
nfsd_cross_mnt(struct svc_rqst * rqstp,struct dentry ** dpp,struct svc_export ** expp)59 nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
60 struct svc_export **expp)
61 {
62 struct svc_export *exp = *expp, *exp2 = NULL;
63 struct dentry *dentry = *dpp;
64 struct path path = {.mnt = mntget(exp->ex_path.mnt),
65 .dentry = dget(dentry)};
66 int err = 0;
67
68 err = follow_down(&path);
69 if (err < 0)
70 goto out;
71 if (path.mnt == exp->ex_path.mnt && path.dentry == dentry &&
72 nfsd_mountpoint(dentry, exp) == 2) {
73 /* This is only a mountpoint in some other namespace */
74 path_put(&path);
75 goto out;
76 }
77
78 exp2 = rqst_exp_get_by_name(rqstp, &path);
79 if (IS_ERR(exp2)) {
80 err = PTR_ERR(exp2);
81 /*
82 * We normally allow NFS clients to continue
83 * "underneath" a mountpoint that is not exported.
84 * The exception is V4ROOT, where no traversal is ever
85 * allowed without an explicit export of the new
86 * directory.
87 */
88 if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
89 err = 0;
90 path_put(&path);
91 goto out;
92 }
93 if (nfsd_v4client(rqstp) ||
94 (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
95 /* successfully crossed mount point */
96 /*
97 * This is subtle: path.dentry is *not* on path.mnt
98 * at this point. The only reason we are safe is that
99 * original mnt is pinned down by exp, so we should
100 * put path *before* putting exp
101 */
102 *dpp = path.dentry;
103 path.dentry = dentry;
104 *expp = exp2;
105 exp2 = exp;
106 }
107 path_put(&path);
108 exp_put(exp2);
109 out:
110 return err;
111 }
112
follow_to_parent(struct path * path)113 static void follow_to_parent(struct path *path)
114 {
115 struct dentry *dp;
116
117 while (path->dentry == path->mnt->mnt_root && follow_up(path))
118 ;
119 dp = dget_parent(path->dentry);
120 dput(path->dentry);
121 path->dentry = dp;
122 }
123
nfsd_lookup_parent(struct svc_rqst * rqstp,struct dentry * dparent,struct svc_export ** exp,struct dentry ** dentryp)124 static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
125 {
126 struct svc_export *exp2;
127 struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
128 .dentry = dget(dparent)};
129
130 follow_to_parent(&path);
131
132 exp2 = rqst_exp_parent(rqstp, &path);
133 if (PTR_ERR(exp2) == -ENOENT) {
134 *dentryp = dget(dparent);
135 } else if (IS_ERR(exp2)) {
136 path_put(&path);
137 return PTR_ERR(exp2);
138 } else {
139 *dentryp = dget(path.dentry);
140 exp_put(*exp);
141 *exp = exp2;
142 }
143 path_put(&path);
144 return 0;
145 }
146
147 /*
148 * For nfsd purposes, we treat V4ROOT exports as though there was an
149 * export at *every* directory.
150 * We return:
151 * '1' if this dentry *must* be an export point,
152 * '2' if it might be, if there is really a mount here, and
153 * '0' if there is no chance of an export point here.
154 */
nfsd_mountpoint(struct dentry * dentry,struct svc_export * exp)155 int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
156 {
157 if (!d_inode(dentry))
158 return 0;
159 if (exp->ex_flags & NFSEXP_V4ROOT)
160 return 1;
161 if (nfsd4_is_junction(dentry))
162 return 1;
163 if (d_mountpoint(dentry))
164 /*
165 * Might only be a mountpoint in a different namespace,
166 * but we need to check.
167 */
168 return 2;
169 return 0;
170 }
171
172 __be32
nfsd_lookup_dentry(struct svc_rqst * rqstp,struct svc_fh * fhp,const char * name,unsigned int len,struct svc_export ** exp_ret,struct dentry ** dentry_ret)173 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
174 const char *name, unsigned int len,
175 struct svc_export **exp_ret, struct dentry **dentry_ret)
176 {
177 struct svc_export *exp;
178 struct dentry *dparent;
179 struct dentry *dentry;
180 int host_err;
181
182 dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
183
184 dparent = fhp->fh_dentry;
185 exp = exp_get(fhp->fh_export);
186
187 /* Lookup the name, but don't follow links */
188 if (isdotent(name, len)) {
189 if (len==1)
190 dentry = dget(dparent);
191 else if (dparent != exp->ex_path.dentry)
192 dentry = dget_parent(dparent);
193 else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
194 dentry = dget(dparent); /* .. == . just like at / */
195 else {
196 /* checking mountpoint crossing is very different when stepping up */
197 host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
198 if (host_err)
199 goto out_nfserr;
200 }
201 } else {
202 dentry = lookup_one_len_unlocked(name, dparent, len);
203 host_err = PTR_ERR(dentry);
204 if (IS_ERR(dentry))
205 goto out_nfserr;
206 if (nfsd_mountpoint(dentry, exp)) {
207 host_err = nfsd_cross_mnt(rqstp, &dentry, &exp);
208 if (host_err) {
209 dput(dentry);
210 goto out_nfserr;
211 }
212 }
213 }
214 *dentry_ret = dentry;
215 *exp_ret = exp;
216 return 0;
217
218 out_nfserr:
219 exp_put(exp);
220 return nfserrno(host_err);
221 }
222
223 /**
224 * nfsd_lookup - look up a single path component for nfsd
225 *
226 * @rqstp: the request context
227 * @fhp: the file handle of the directory
228 * @name: the component name, or %NULL to look up parent
229 * @len: length of name to examine
230 * @resfh: pointer to pre-initialised filehandle to hold result.
231 *
232 * Look up one component of a pathname.
233 * N.B. After this call _both_ fhp and resfh need an fh_put
234 *
235 * If the lookup would cross a mountpoint, and the mounted filesystem
236 * is exported to the client with NFSEXP_NOHIDE, then the lookup is
237 * accepted as it stands and the mounted directory is
238 * returned. Otherwise the covered directory is returned.
239 * NOTE: this mountpoint crossing is not supported properly by all
240 * clients and is explicitly disallowed for NFSv3
241 *
242 */
243 __be32
nfsd_lookup(struct svc_rqst * rqstp,struct svc_fh * fhp,const char * name,unsigned int len,struct svc_fh * resfh)244 nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
245 unsigned int len, struct svc_fh *resfh)
246 {
247 struct svc_export *exp;
248 struct dentry *dentry;
249 __be32 err;
250
251 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
252 if (err)
253 return err;
254 err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
255 if (err)
256 return err;
257 err = check_nfsd_access(exp, rqstp);
258 if (err)
259 goto out;
260 /*
261 * Note: we compose the file handle now, but as the
262 * dentry may be negative, it may need to be updated.
263 */
264 err = fh_compose(resfh, exp, dentry, fhp);
265 if (!err && d_really_is_negative(dentry))
266 err = nfserr_noent;
267 out:
268 dput(dentry);
269 exp_put(exp);
270 return err;
271 }
272
273 /*
274 * Commit metadata changes to stable storage.
275 */
276 static int
commit_inode_metadata(struct inode * inode)277 commit_inode_metadata(struct inode *inode)
278 {
279 const struct export_operations *export_ops = inode->i_sb->s_export_op;
280
281 if (export_ops->commit_metadata)
282 return export_ops->commit_metadata(inode);
283 return sync_inode_metadata(inode, 1);
284 }
285
286 static int
commit_metadata(struct svc_fh * fhp)287 commit_metadata(struct svc_fh *fhp)
288 {
289 struct inode *inode = d_inode(fhp->fh_dentry);
290
291 if (!EX_ISSYNC(fhp->fh_export))
292 return 0;
293 return commit_inode_metadata(inode);
294 }
295
296 /*
297 * Go over the attributes and take care of the small differences between
298 * NFS semantics and what Linux expects.
299 */
300 static void
nfsd_sanitize_attrs(struct inode * inode,struct iattr * iap)301 nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
302 {
303 /* Ignore mode updates on symlinks */
304 if (S_ISLNK(inode->i_mode))
305 iap->ia_valid &= ~ATTR_MODE;
306
307 /* sanitize the mode change */
308 if (iap->ia_valid & ATTR_MODE) {
309 iap->ia_mode &= S_IALLUGO;
310 iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
311 }
312
313 /* Revoke setuid/setgid on chown */
314 if (!S_ISDIR(inode->i_mode) &&
315 ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
316 iap->ia_valid |= ATTR_KILL_PRIV;
317 if (iap->ia_valid & ATTR_MODE) {
318 /* we're setting mode too, just clear the s*id bits */
319 iap->ia_mode &= ~S_ISUID;
320 if (iap->ia_mode & S_IXGRP)
321 iap->ia_mode &= ~S_ISGID;
322 } else {
323 /* set ATTR_KILL_* bits and let VFS handle it */
324 iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
325 }
326 }
327 }
328
329 static __be32
nfsd_get_write_access(struct svc_rqst * rqstp,struct svc_fh * fhp,struct iattr * iap)330 nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
331 struct iattr *iap)
332 {
333 struct inode *inode = d_inode(fhp->fh_dentry);
334
335 if (iap->ia_size < inode->i_size) {
336 __be32 err;
337
338 err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
339 NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
340 if (err)
341 return err;
342 }
343 return nfserrno(get_write_access(inode));
344 }
345
__nfsd_setattr(struct dentry * dentry,struct iattr * iap)346 static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap)
347 {
348 int host_err;
349
350 if (iap->ia_valid & ATTR_SIZE) {
351 /*
352 * RFC5661, Section 18.30.4:
353 * Changing the size of a file with SETATTR indirectly
354 * changes the time_modify and change attributes.
355 *
356 * (and similar for the older RFCs)
357 */
358 struct iattr size_attr = {
359 .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME,
360 .ia_size = iap->ia_size,
361 };
362
363 if (iap->ia_size < 0)
364 return -EFBIG;
365
366 host_err = notify_change(&init_user_ns, dentry, &size_attr, NULL);
367 if (host_err)
368 return host_err;
369 iap->ia_valid &= ~ATTR_SIZE;
370
371 /*
372 * Avoid the additional setattr call below if the only other
373 * attribute that the client sends is the mtime, as we update
374 * it as part of the size change above.
375 */
376 if ((iap->ia_valid & ~ATTR_MTIME) == 0)
377 return 0;
378 }
379
380 if (!iap->ia_valid)
381 return 0;
382
383 iap->ia_valid |= ATTR_CTIME;
384 return notify_change(&init_user_ns, dentry, iap, NULL);
385 }
386
387 /**
388 * nfsd_setattr - Set various file attributes.
389 * @rqstp: controlling RPC transaction
390 * @fhp: filehandle of target
391 * @attr: attributes to set
392 * @check_guard: set to 1 if guardtime is a valid timestamp
393 * @guardtime: do not act if ctime.tv_sec does not match this timestamp
394 *
395 * This call may adjust the contents of @attr (in particular, this
396 * call may change the bits in the na_iattr.ia_valid field).
397 *
398 * Returns nfs_ok on success, otherwise an NFS status code is
399 * returned. Caller must release @fhp by calling fh_put in either
400 * case.
401 */
402 __be32
nfsd_setattr(struct svc_rqst * rqstp,struct svc_fh * fhp,struct nfsd_attrs * attr,int check_guard,time64_t guardtime)403 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
404 struct nfsd_attrs *attr,
405 int check_guard, time64_t guardtime)
406 {
407 struct dentry *dentry;
408 struct inode *inode;
409 struct iattr *iap = attr->na_iattr;
410 int accmode = NFSD_MAY_SATTR;
411 umode_t ftype = 0;
412 __be32 err;
413 int host_err;
414 bool get_write_count;
415 bool size_change = (iap->ia_valid & ATTR_SIZE);
416 int retries;
417
418 if (iap->ia_valid & ATTR_SIZE) {
419 accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
420 ftype = S_IFREG;
421 }
422
423 /*
424 * If utimes(2) and friends are called with times not NULL, we should
425 * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission
426 * will return EACCES, when the caller's effective UID does not match
427 * the owner of the file, and the caller is not privileged. In this
428 * situation, we should return EPERM(notify_change will return this).
429 */
430 if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) {
431 accmode |= NFSD_MAY_OWNER_OVERRIDE;
432 if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET)))
433 accmode |= NFSD_MAY_WRITE;
434 }
435
436 /* Callers that do fh_verify should do the fh_want_write: */
437 get_write_count = !fhp->fh_dentry;
438
439 /* Get inode */
440 err = fh_verify(rqstp, fhp, ftype, accmode);
441 if (err)
442 return err;
443 if (get_write_count) {
444 host_err = fh_want_write(fhp);
445 if (host_err)
446 goto out;
447 }
448
449 dentry = fhp->fh_dentry;
450 inode = d_inode(dentry);
451
452 nfsd_sanitize_attrs(inode, iap);
453
454 if (check_guard && guardtime != inode->i_ctime.tv_sec)
455 return nfserr_notsync;
456
457 /*
458 * The size case is special, it changes the file in addition to the
459 * attributes, and file systems don't expect it to be mixed with
460 * "random" attribute changes. We thus split out the size change
461 * into a separate call to ->setattr, and do the rest as a separate
462 * setattr call.
463 */
464 if (size_change) {
465 err = nfsd_get_write_access(rqstp, fhp, iap);
466 if (err)
467 return err;
468 }
469
470 inode_lock(inode);
471 for (retries = 1;;) {
472 host_err = __nfsd_setattr(dentry, iap);
473 if (host_err != -EAGAIN || !retries--)
474 break;
475 if (!nfsd_wait_for_delegreturn(rqstp, inode))
476 break;
477 }
478 if (attr->na_seclabel && attr->na_seclabel->len)
479 attr->na_labelerr = security_inode_setsecctx(dentry,
480 attr->na_seclabel->data, attr->na_seclabel->len);
481 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) && attr->na_pacl)
482 attr->na_aclerr = set_posix_acl(&init_user_ns,
483 inode, ACL_TYPE_ACCESS,
484 attr->na_pacl);
485 if (IS_ENABLED(CONFIG_FS_POSIX_ACL) &&
486 !attr->na_aclerr && attr->na_dpacl && S_ISDIR(inode->i_mode))
487 attr->na_aclerr = set_posix_acl(&init_user_ns,
488 inode, ACL_TYPE_DEFAULT,
489 attr->na_dpacl);
490 inode_unlock(inode);
491 if (size_change)
492 put_write_access(inode);
493 out:
494 if (!host_err)
495 host_err = commit_metadata(fhp);
496 return nfserrno(host_err);
497 }
498
499 #if defined(CONFIG_NFSD_V4)
500 /*
501 * NFS junction information is stored in an extended attribute.
502 */
503 #define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs"
504
505 /**
506 * nfsd4_is_junction - Test if an object could be an NFS junction
507 *
508 * @dentry: object to test
509 *
510 * Returns 1 if "dentry" appears to contain NFS junction information.
511 * Otherwise 0 is returned.
512 */
nfsd4_is_junction(struct dentry * dentry)513 int nfsd4_is_junction(struct dentry *dentry)
514 {
515 struct inode *inode = d_inode(dentry);
516
517 if (inode == NULL)
518 return 0;
519 if (inode->i_mode & S_IXUGO)
520 return 0;
521 if (!(inode->i_mode & S_ISVTX))
522 return 0;
523 if (vfs_getxattr(&init_user_ns, dentry, NFSD_JUNCTION_XATTR_NAME,
524 NULL, 0) <= 0)
525 return 0;
526 return 1;
527 }
528
nfsd4_get_cstate(struct svc_rqst * rqstp)529 static struct nfsd4_compound_state *nfsd4_get_cstate(struct svc_rqst *rqstp)
530 {
531 return &((struct nfsd4_compoundres *)rqstp->rq_resp)->cstate;
532 }
533
nfsd4_clone_file_range(struct svc_rqst * rqstp,struct nfsd_file * nf_src,u64 src_pos,struct nfsd_file * nf_dst,u64 dst_pos,u64 count,bool sync)534 __be32 nfsd4_clone_file_range(struct svc_rqst *rqstp,
535 struct nfsd_file *nf_src, u64 src_pos,
536 struct nfsd_file *nf_dst, u64 dst_pos,
537 u64 count, bool sync)
538 {
539 struct file *src = nf_src->nf_file;
540 struct file *dst = nf_dst->nf_file;
541 errseq_t since;
542 loff_t cloned;
543 __be32 ret = 0;
544
545 since = READ_ONCE(dst->f_wb_err);
546 cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
547 if (cloned < 0) {
548 ret = nfserrno(cloned);
549 goto out_err;
550 }
551 if (count && cloned != count) {
552 ret = nfserrno(-EINVAL);
553 goto out_err;
554 }
555 if (sync) {
556 loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
557 int status = vfs_fsync_range(dst, dst_pos, dst_end, 0);
558
559 if (!status)
560 status = filemap_check_wb_err(dst->f_mapping, since);
561 if (!status)
562 status = commit_inode_metadata(file_inode(src));
563 if (status < 0) {
564 struct nfsd_net *nn = net_generic(nf_dst->nf_net,
565 nfsd_net_id);
566
567 trace_nfsd_clone_file_range_err(rqstp,
568 &nfsd4_get_cstate(rqstp)->save_fh,
569 src_pos,
570 &nfsd4_get_cstate(rqstp)->current_fh,
571 dst_pos,
572 count, status);
573 nfsd_reset_write_verifier(nn);
574 trace_nfsd_writeverf_reset(nn, rqstp, status);
575 ret = nfserrno(status);
576 }
577 }
578 out_err:
579 return ret;
580 }
581
nfsd_copy_file_range(struct file * src,u64 src_pos,struct file * dst,u64 dst_pos,u64 count)582 ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
583 u64 dst_pos, u64 count)
584 {
585 ssize_t ret;
586
587 /*
588 * Limit copy to 4MB to prevent indefinitely blocking an nfsd
589 * thread and client rpc slot. The choice of 4MB is somewhat
590 * arbitrary. We might instead base this on r/wsize, or make it
591 * tunable, or use a time instead of a byte limit, or implement
592 * asynchronous copy. In theory a client could also recognize a
593 * limit like this and pipeline multiple COPY requests.
594 */
595 count = min_t(u64, count, 1 << 22);
596 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
597
598 if (ret == -EOPNOTSUPP || ret == -EXDEV)
599 ret = vfs_copy_file_range(src, src_pos, dst, dst_pos, count,
600 COPY_FILE_SPLICE);
601 return ret;
602 }
603
nfsd4_vfs_fallocate(struct svc_rqst * rqstp,struct svc_fh * fhp,struct file * file,loff_t offset,loff_t len,int flags)604 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
605 struct file *file, loff_t offset, loff_t len,
606 int flags)
607 {
608 int error;
609
610 if (!S_ISREG(file_inode(file)->i_mode))
611 return nfserr_inval;
612
613 error = vfs_fallocate(file, flags, offset, len);
614 if (!error)
615 error = commit_metadata(fhp);
616
617 return nfserrno(error);
618 }
619 #endif /* defined(CONFIG_NFSD_V4) */
620
621 /*
622 * Check server access rights to a file system object
623 */
624 struct accessmap {
625 u32 access;
626 int how;
627 };
628 static struct accessmap nfs3_regaccess[] = {
629 { NFS3_ACCESS_READ, NFSD_MAY_READ },
630 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
631 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC },
632 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE },
633
634 #ifdef CONFIG_NFSD_V4
635 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
636 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
637 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
638 #endif
639
640 { 0, 0 }
641 };
642
643 static struct accessmap nfs3_diraccess[] = {
644 { NFS3_ACCESS_READ, NFSD_MAY_READ },
645 { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC },
646 { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
647 { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE },
648 { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE },
649
650 #ifdef CONFIG_NFSD_V4
651 { NFS4_ACCESS_XAREAD, NFSD_MAY_READ },
652 { NFS4_ACCESS_XAWRITE, NFSD_MAY_WRITE },
653 { NFS4_ACCESS_XALIST, NFSD_MAY_READ },
654 #endif
655
656 { 0, 0 }
657 };
658
659 static struct accessmap nfs3_anyaccess[] = {
660 /* Some clients - Solaris 2.6 at least, make an access call
661 * to the server to check for access for things like /dev/null
662 * (which really, the server doesn't care about). So
663 * We provide simple access checking for them, looking
664 * mainly at mode bits, and we make sure to ignore read-only
665 * filesystem checks
666 */
667 { NFS3_ACCESS_READ, NFSD_MAY_READ },
668 { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC },
669 { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
670 { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS },
671
672 { 0, 0 }
673 };
674
675 __be32
nfsd_access(struct svc_rqst * rqstp,struct svc_fh * fhp,u32 * access,u32 * supported)676 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
677 {
678 struct accessmap *map;
679 struct svc_export *export;
680 struct dentry *dentry;
681 u32 query, result = 0, sresult = 0;
682 __be32 error;
683
684 error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
685 if (error)
686 goto out;
687
688 export = fhp->fh_export;
689 dentry = fhp->fh_dentry;
690
691 if (d_is_reg(dentry))
692 map = nfs3_regaccess;
693 else if (d_is_dir(dentry))
694 map = nfs3_diraccess;
695 else
696 map = nfs3_anyaccess;
697
698
699 query = *access;
700 for (; map->access; map++) {
701 if (map->access & query) {
702 __be32 err2;
703
704 sresult |= map->access;
705
706 err2 = nfsd_permission(rqstp, export, dentry, map->how);
707 switch (err2) {
708 case nfs_ok:
709 result |= map->access;
710 break;
711
712 /* the following error codes just mean the access was not allowed,
713 * rather than an error occurred */
714 case nfserr_rofs:
715 case nfserr_acces:
716 case nfserr_perm:
717 /* simply don't "or" in the access bit. */
718 break;
719 default:
720 error = err2;
721 goto out;
722 }
723 }
724 }
725 *access = result;
726 if (supported)
727 *supported = sresult;
728
729 out:
730 return error;
731 }
732
nfsd_open_break_lease(struct inode * inode,int access)733 int nfsd_open_break_lease(struct inode *inode, int access)
734 {
735 unsigned int mode;
736
737 if (access & NFSD_MAY_NOT_BREAK_LEASE)
738 return 0;
739 mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
740 return break_lease(inode, mode | O_NONBLOCK);
741 }
742
743 /*
744 * Open an existing file or directory.
745 * The may_flags argument indicates the type of open (read/write/lock)
746 * and additional flags.
747 * N.B. After this call fhp needs an fh_put
748 */
749 static __be32
__nfsd_open(struct svc_rqst * rqstp,struct svc_fh * fhp,umode_t type,int may_flags,struct file ** filp)750 __nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
751 int may_flags, struct file **filp)
752 {
753 struct path path;
754 struct inode *inode;
755 struct file *file;
756 int flags = O_RDONLY|O_LARGEFILE;
757 __be32 err;
758 int host_err = 0;
759
760 path.mnt = fhp->fh_export->ex_path.mnt;
761 path.dentry = fhp->fh_dentry;
762 inode = d_inode(path.dentry);
763
764 err = nfserr_perm;
765 if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE))
766 goto out;
767
768 if (!inode->i_fop)
769 goto out;
770
771 host_err = nfsd_open_break_lease(inode, may_flags);
772 if (host_err) /* NOMEM or WOULDBLOCK */
773 goto out_nfserr;
774
775 if (may_flags & NFSD_MAY_WRITE) {
776 if (may_flags & NFSD_MAY_READ)
777 flags = O_RDWR|O_LARGEFILE;
778 else
779 flags = O_WRONLY|O_LARGEFILE;
780 }
781
782 file = dentry_open(&path, flags, current_cred());
783 if (IS_ERR(file)) {
784 host_err = PTR_ERR(file);
785 goto out_nfserr;
786 }
787
788 host_err = ima_file_check(file, may_flags);
789 if (host_err) {
790 fput(file);
791 goto out_nfserr;
792 }
793
794 if (may_flags & NFSD_MAY_64BIT_COOKIE)
795 file->f_mode |= FMODE_64BITHASH;
796 else
797 file->f_mode |= FMODE_32BITHASH;
798
799 *filp = file;
800 out_nfserr:
801 err = nfserrno(host_err);
802 out:
803 return err;
804 }
805
806 __be32
nfsd_open(struct svc_rqst * rqstp,struct svc_fh * fhp,umode_t type,int may_flags,struct file ** filp)807 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
808 int may_flags, struct file **filp)
809 {
810 __be32 err;
811 bool retried = false;
812
813 validate_process_creds();
814 /*
815 * If we get here, then the client has already done an "open",
816 * and (hopefully) checked permission - so allow OWNER_OVERRIDE
817 * in case a chmod has now revoked permission.
818 *
819 * Arguably we should also allow the owner override for
820 * directories, but we never have and it doesn't seem to have
821 * caused anyone a problem. If we were to change this, note
822 * also that our filldir callbacks would need a variant of
823 * lookup_one_len that doesn't check permissions.
824 */
825 if (type == S_IFREG)
826 may_flags |= NFSD_MAY_OWNER_OVERRIDE;
827 retry:
828 err = fh_verify(rqstp, fhp, type, may_flags);
829 if (!err) {
830 err = __nfsd_open(rqstp, fhp, type, may_flags, filp);
831 if (err == nfserr_stale && !retried) {
832 retried = true;
833 fh_put(fhp);
834 goto retry;
835 }
836 }
837 validate_process_creds();
838 return err;
839 }
840
841 /**
842 * nfsd_open_verified - Open a regular file for the filecache
843 * @rqstp: RPC request
844 * @fhp: NFS filehandle of the file to open
845 * @may_flags: internal permission flags
846 * @filp: OUT: open "struct file *"
847 *
848 * Returns an nfsstat value in network byte order.
849 */
850 __be32
nfsd_open_verified(struct svc_rqst * rqstp,struct svc_fh * fhp,int may_flags,struct file ** filp)851 nfsd_open_verified(struct svc_rqst *rqstp, struct svc_fh *fhp, int may_flags,
852 struct file **filp)
853 {
854 __be32 err;
855
856 validate_process_creds();
857 err = __nfsd_open(rqstp, fhp, S_IFREG, may_flags, filp);
858 validate_process_creds();
859 return err;
860 }
861
862 /*
863 * Grab and keep cached pages associated with a file in the svc_rqst
864 * so that they can be passed to the network sendmsg/sendpage routines
865 * directly. They will be released after the sending has completed.
866 */
867 static int
nfsd_splice_actor(struct pipe_inode_info * pipe,struct pipe_buffer * buf,struct splice_desc * sd)868 nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
869 struct splice_desc *sd)
870 {
871 struct svc_rqst *rqstp = sd->u.data;
872 struct page *page = buf->page; // may be a compound one
873 unsigned offset = buf->offset;
874 struct page *last_page;
875
876 last_page = page + (offset + sd->len - 1) / PAGE_SIZE;
877 for (page += offset / PAGE_SIZE; page <= last_page; page++)
878 svc_rqst_replace_page(rqstp, page);
879 if (rqstp->rq_res.page_len == 0) // first call
880 rqstp->rq_res.page_base = offset % PAGE_SIZE;
881 rqstp->rq_res.page_len += sd->len;
882 return sd->len;
883 }
884
nfsd_direct_splice_actor(struct pipe_inode_info * pipe,struct splice_desc * sd)885 static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
886 struct splice_desc *sd)
887 {
888 return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
889 }
890
nfsd_eof_on_read(struct file * file,loff_t offset,ssize_t len,size_t expected)891 static u32 nfsd_eof_on_read(struct file *file, loff_t offset, ssize_t len,
892 size_t expected)
893 {
894 if (expected != 0 && len == 0)
895 return 1;
896 if (offset+len >= i_size_read(file_inode(file)))
897 return 1;
898 return 0;
899 }
900
nfsd_finish_read(struct svc_rqst * rqstp,struct svc_fh * fhp,struct file * file,loff_t offset,unsigned long * count,u32 * eof,ssize_t host_err)901 static __be32 nfsd_finish_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
902 struct file *file, loff_t offset,
903 unsigned long *count, u32 *eof, ssize_t host_err)
904 {
905 if (host_err >= 0) {
906 nfsd_stats_io_read_add(fhp->fh_export, host_err);
907 *eof = nfsd_eof_on_read(file, offset, host_err, *count);
908 *count = host_err;
909 fsnotify_access(file);
910 trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
911 return 0;
912 } else {
913 trace_nfsd_read_err(rqstp, fhp, offset, host_err);
914 return nfserrno(host_err);
915 }
916 }
917
nfsd_splice_read(struct svc_rqst * rqstp,struct svc_fh * fhp,struct file * file,loff_t offset,unsigned long * count,u32 * eof)918 __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
919 struct file *file, loff_t offset, unsigned long *count,
920 u32 *eof)
921 {
922 struct splice_desc sd = {
923 .len = 0,
924 .total_len = *count,
925 .pos = offset,
926 .u.data = rqstp,
927 };
928 ssize_t host_err;
929
930 trace_nfsd_read_splice(rqstp, fhp, offset, *count);
931 rqstp->rq_next_page = rqstp->rq_respages + 1;
932 host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
933 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
934 }
935
nfsd_readv(struct svc_rqst * rqstp,struct svc_fh * fhp,struct file * file,loff_t offset,struct kvec * vec,int vlen,unsigned long * count,u32 * eof)936 __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
937 struct file *file, loff_t offset,
938 struct kvec *vec, int vlen, unsigned long *count,
939 u32 *eof)
940 {
941 struct iov_iter iter;
942 loff_t ppos = offset;
943 ssize_t host_err;
944
945 trace_nfsd_read_vector(rqstp, fhp, offset, *count);
946 iov_iter_kvec(&iter, READ, vec, vlen, *count);
947 host_err = vfs_iter_read(file, &iter, &ppos, 0);
948 return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
949 }
950
951 /*
952 * Gathered writes: If another process is currently writing to the file,
953 * there's a high chance this is another nfsd (triggered by a bulk write
954 * from a client's biod). Rather than syncing the file with each write
955 * request, we sleep for 10 msec.
956 *
957 * I don't know if this roughly approximates C. Juszak's idea of
958 * gathered writes, but it's a nice and simple solution (IMHO), and it
959 * seems to work:-)
960 *
961 * Note: we do this only in the NFSv2 case, since v3 and higher have a
962 * better tool (separate unstable writes and commits) for solving this
963 * problem.
964 */
wait_for_concurrent_writes(struct file * file)965 static int wait_for_concurrent_writes(struct file *file)
966 {
967 struct inode *inode = file_inode(file);
968 static ino_t last_ino;
969 static dev_t last_dev;
970 int err = 0;
971
972 if (atomic_read(&inode->i_writecount) > 1
973 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
974 dprintk("nfsd: write defer %d\n", task_pid_nr(current));
975 msleep(10);
976 dprintk("nfsd: write resume %d\n", task_pid_nr(current));
977 }
978
979 if (inode->i_state & I_DIRTY) {
980 dprintk("nfsd: write sync %d\n", task_pid_nr(current));
981 err = vfs_fsync(file, 0);
982 }
983 last_ino = inode->i_ino;
984 last_dev = inode->i_sb->s_dev;
985 return err;
986 }
987
988 __be32
nfsd_vfs_write(struct svc_rqst * rqstp,struct svc_fh * fhp,struct nfsd_file * nf,loff_t offset,struct kvec * vec,int vlen,unsigned long * cnt,int stable,__be32 * verf)989 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
990 loff_t offset, struct kvec *vec, int vlen,
991 unsigned long *cnt, int stable,
992 __be32 *verf)
993 {
994 struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
995 struct file *file = nf->nf_file;
996 struct super_block *sb = file_inode(file)->i_sb;
997 struct svc_export *exp;
998 struct iov_iter iter;
999 errseq_t since;
1000 __be32 nfserr;
1001 int host_err;
1002 int use_wgather;
1003 loff_t pos = offset;
1004 unsigned long exp_op_flags = 0;
1005 unsigned int pflags = current->flags;
1006 rwf_t flags = 0;
1007 bool restore_flags = false;
1008
1009 trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
1010
1011 if (sb->s_export_op)
1012 exp_op_flags = sb->s_export_op->flags;
1013
1014 if (test_bit(RQ_LOCAL, &rqstp->rq_flags) &&
1015 !(exp_op_flags & EXPORT_OP_REMOTE_FS)) {
1016 /*
1017 * We want throttling in balance_dirty_pages()
1018 * and shrink_inactive_list() to only consider
1019 * the backingdev we are writing to, so that nfs to
1020 * localhost doesn't cause nfsd to lock up due to all
1021 * the client's dirty pages or its congested queue.
1022 */
1023 current->flags |= PF_LOCAL_THROTTLE;
1024 restore_flags = true;
1025 }
1026
1027 exp = fhp->fh_export;
1028 use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
1029
1030 if (!EX_ISSYNC(exp))
1031 stable = NFS_UNSTABLE;
1032
1033 if (stable && !use_wgather)
1034 flags |= RWF_SYNC;
1035
1036 iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt);
1037 since = READ_ONCE(file->f_wb_err);
1038 if (verf)
1039 nfsd_copy_write_verifier(verf, nn);
1040 host_err = vfs_iter_write(file, &iter, &pos, flags);
1041 if (host_err < 0) {
1042 nfsd_reset_write_verifier(nn);
1043 trace_nfsd_writeverf_reset(nn, rqstp, host_err);
1044 goto out_nfserr;
1045 }
1046 *cnt = host_err;
1047 nfsd_stats_io_write_add(exp, *cnt);
1048 fsnotify_modify(file);
1049 host_err = filemap_check_wb_err(file->f_mapping, since);
1050 if (host_err < 0)
1051 goto out_nfserr;
1052
1053 if (stable && use_wgather) {
1054 host_err = wait_for_concurrent_writes(file);
1055 if (host_err < 0) {
1056 nfsd_reset_write_verifier(nn);
1057 trace_nfsd_writeverf_reset(nn, rqstp, host_err);
1058 }
1059 }
1060
1061 out_nfserr:
1062 if (host_err >= 0) {
1063 trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
1064 nfserr = nfs_ok;
1065 } else {
1066 trace_nfsd_write_err(rqstp, fhp, offset, host_err);
1067 nfserr = nfserrno(host_err);
1068 }
1069 if (restore_flags)
1070 current_restore_flags(pflags, PF_LOCAL_THROTTLE);
1071 return nfserr;
1072 }
1073
1074 /*
1075 * Read data from a file. count must contain the requested read count
1076 * on entry. On return, *count contains the number of bytes actually read.
1077 * N.B. After this call fhp needs an fh_put
1078 */
nfsd_read(struct svc_rqst * rqstp,struct svc_fh * fhp,loff_t offset,struct kvec * vec,int vlen,unsigned long * count,u32 * eof)1079 __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
1080 loff_t offset, struct kvec *vec, int vlen, unsigned long *count,
1081 u32 *eof)
1082 {
1083 struct nfsd_file *nf;
1084 struct file *file;
1085 __be32 err;
1086
1087 trace_nfsd_read_start(rqstp, fhp, offset, *count);
1088 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_READ, &nf);
1089 if (err)
1090 return err;
1091
1092 file = nf->nf_file;
1093 if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
1094 err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
1095 else
1096 err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof);
1097
1098 nfsd_file_put(nf);
1099
1100 trace_nfsd_read_done(rqstp, fhp, offset, *count);
1101
1102 return err;
1103 }
1104
1105 /*
1106 * Write data to a file.
1107 * The stable flag requests synchronous writes.
1108 * N.B. After this call fhp needs an fh_put
1109 */
1110 __be32
nfsd_write(struct svc_rqst * rqstp,struct svc_fh * fhp,loff_t offset,struct kvec * vec,int vlen,unsigned long * cnt,int stable,__be32 * verf)1111 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
1112 struct kvec *vec, int vlen, unsigned long *cnt, int stable,
1113 __be32 *verf)
1114 {
1115 struct nfsd_file *nf;
1116 __be32 err;
1117
1118 trace_nfsd_write_start(rqstp, fhp, offset, *cnt);
1119
1120 err = nfsd_file_acquire(rqstp, fhp, NFSD_MAY_WRITE, &nf);
1121 if (err)
1122 goto out;
1123
1124 err = nfsd_vfs_write(rqstp, fhp, nf, offset, vec,
1125 vlen, cnt, stable, verf);
1126 nfsd_file_put(nf);
1127 out:
1128 trace_nfsd_write_done(rqstp, fhp, offset, *cnt);
1129 return err;
1130 }
1131
1132 /**
1133 * nfsd_commit - Commit pending writes to stable storage
1134 * @rqstp: RPC request being processed
1135 * @fhp: NFS filehandle
1136 * @offset: raw offset from beginning of file
1137 * @count: raw count of bytes to sync
1138 * @verf: filled in with the server's current write verifier
1139 *
1140 * Note: we guarantee that data that lies within the range specified
1141 * by the 'offset' and 'count' parameters will be synced. The server
1142 * is permitted to sync data that lies outside this range at the
1143 * same time.
1144 *
1145 * Unfortunately we cannot lock the file to make sure we return full WCC
1146 * data to the client, as locking happens lower down in the filesystem.
1147 *
1148 * Return values:
1149 * An nfsstat value in network byte order.
1150 */
1151 __be32
nfsd_commit(struct svc_rqst * rqstp,struct svc_fh * fhp,u64 offset,u32 count,__be32 * verf)1152 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, u64 offset,
1153 u32 count, __be32 *verf)
1154 {
1155 u64 maxbytes;
1156 loff_t start, end;
1157 struct nfsd_net *nn;
1158 struct nfsd_file *nf;
1159 __be32 err;
1160
1161 err = nfsd_file_acquire(rqstp, fhp,
1162 NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &nf);
1163 if (err)
1164 goto out;
1165
1166 /*
1167 * Convert the client-provided (offset, count) range to a
1168 * (start, end) range. If the client-provided range falls
1169 * outside the maximum file size of the underlying FS,
1170 * clamp the sync range appropriately.
1171 */
1172 start = 0;
1173 end = LLONG_MAX;
1174 maxbytes = (u64)fhp->fh_dentry->d_sb->s_maxbytes;
1175 if (offset < maxbytes) {
1176 start = offset;
1177 if (count && (offset + count - 1 < maxbytes))
1178 end = offset + count - 1;
1179 }
1180
1181 nn = net_generic(nf->nf_net, nfsd_net_id);
1182 if (EX_ISSYNC(fhp->fh_export)) {
1183 errseq_t since = READ_ONCE(nf->nf_file->f_wb_err);
1184 int err2;
1185
1186 err2 = vfs_fsync_range(nf->nf_file, start, end, 0);
1187 switch (err2) {
1188 case 0:
1189 nfsd_copy_write_verifier(verf, nn);
1190 err2 = filemap_check_wb_err(nf->nf_file->f_mapping,
1191 since);
1192 err = nfserrno(err2);
1193 break;
1194 case -EINVAL:
1195 err = nfserr_notsupp;
1196 break;
1197 default:
1198 nfsd_reset_write_verifier(nn);
1199 trace_nfsd_writeverf_reset(nn, rqstp, err2);
1200 err = nfserrno(err2);
1201 }
1202 } else
1203 nfsd_copy_write_verifier(verf, nn);
1204
1205 nfsd_file_put(nf);
1206 out:
1207 return err;
1208 }
1209
1210 /**
1211 * nfsd_create_setattr - Set a created file's attributes
1212 * @rqstp: RPC transaction being executed
1213 * @fhp: NFS filehandle of parent directory
1214 * @resfhp: NFS filehandle of new object
1215 * @attrs: requested attributes of new object
1216 *
1217 * Returns nfs_ok on success, or an nfsstat in network byte order.
1218 */
1219 __be32
nfsd_create_setattr(struct svc_rqst * rqstp,struct svc_fh * fhp,struct svc_fh * resfhp,struct nfsd_attrs * attrs)1220 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
1221 struct svc_fh *resfhp, struct nfsd_attrs *attrs)
1222 {
1223 struct iattr *iap = attrs->na_iattr;
1224 __be32 status;
1225
1226 /*
1227 * Mode has already been set by file creation.
1228 */
1229 iap->ia_valid &= ~ATTR_MODE;
1230
1231 /*
1232 * Setting uid/gid works only for root. Irix appears to
1233 * send along the gid on create when it tries to implement
1234 * setgid directories via NFS:
1235 */
1236 if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
1237 iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
1238
1239 /*
1240 * Callers expect new file metadata to be committed even
1241 * if the attributes have not changed.
1242 */
1243 if (iap->ia_valid)
1244 status = nfsd_setattr(rqstp, resfhp, attrs, 0, (time64_t)0);
1245 else
1246 status = nfserrno(commit_metadata(resfhp));
1247
1248 /*
1249 * Transactional filesystems had a chance to commit changes
1250 * for both parent and child simultaneously making the
1251 * following commit_metadata a noop in many cases.
1252 */
1253 if (!status)
1254 status = nfserrno(commit_metadata(fhp));
1255
1256 /*
1257 * Update the new filehandle to pick up the new attributes.
1258 */
1259 if (!status)
1260 status = fh_update(resfhp);
1261
1262 return status;
1263 }
1264
1265 /* HPUX client sometimes creates a file in mode 000, and sets size to 0.
1266 * setting size to 0 may fail for some specific file systems by the permission
1267 * checking which requires WRITE permission but the mode is 000.
1268 * we ignore the resizing(to 0) on the just new created file, since the size is
1269 * 0 after file created.
1270 *
1271 * call this only after vfs_create() is called.
1272 * */
1273 static void
nfsd_check_ignore_resizing(struct iattr * iap)1274 nfsd_check_ignore_resizing(struct iattr *iap)
1275 {
1276 if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
1277 iap->ia_valid &= ~ATTR_SIZE;
1278 }
1279
1280 /* The parent directory should already be locked: */
1281 __be32
nfsd_create_locked(struct svc_rqst * rqstp,struct svc_fh * fhp,struct nfsd_attrs * attrs,int type,dev_t rdev,struct svc_fh * resfhp)1282 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
1283 struct nfsd_attrs *attrs,
1284 int type, dev_t rdev, struct svc_fh *resfhp)
1285 {
1286 struct dentry *dentry, *dchild;
1287 struct inode *dirp;
1288 struct iattr *iap = attrs->na_iattr;
1289 __be32 err;
1290 int host_err;
1291
1292 dentry = fhp->fh_dentry;
1293 dirp = d_inode(dentry);
1294
1295 dchild = dget(resfhp->fh_dentry);
1296 err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
1297 if (err)
1298 goto out;
1299
1300 if (!(iap->ia_valid & ATTR_MODE))
1301 iap->ia_mode = 0;
1302 iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type;
1303
1304 if (!IS_POSIXACL(dirp))
1305 iap->ia_mode &= ~current_umask();
1306
1307 err = 0;
1308 host_err = 0;
1309 switch (type) {
1310 case S_IFREG:
1311 host_err = vfs_create(&init_user_ns, dirp, dchild, iap->ia_mode, true);
1312 if (!host_err)
1313 nfsd_check_ignore_resizing(iap);
1314 break;
1315 case S_IFDIR:
1316 host_err = vfs_mkdir(&init_user_ns, dirp, dchild, iap->ia_mode);
1317 if (!host_err && unlikely(d_unhashed(dchild))) {
1318 struct dentry *d;
1319 d = lookup_one_len(dchild->d_name.name,
1320 dchild->d_parent,
1321 dchild->d_name.len);
1322 if (IS_ERR(d)) {
1323 host_err = PTR_ERR(d);
1324 break;
1325 }
1326 if (unlikely(d_is_negative(d))) {
1327 dput(d);
1328 err = nfserr_serverfault;
1329 goto out;
1330 }
1331 dput(resfhp->fh_dentry);
1332 resfhp->fh_dentry = dget(d);
1333 err = fh_update(resfhp);
1334 dput(dchild);
1335 dchild = d;
1336 if (err)
1337 goto out;
1338 }
1339 break;
1340 case S_IFCHR:
1341 case S_IFBLK:
1342 case S_IFIFO:
1343 case S_IFSOCK:
1344 host_err = vfs_mknod(&init_user_ns, dirp, dchild,
1345 iap->ia_mode, rdev);
1346 break;
1347 default:
1348 printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
1349 type);
1350 host_err = -EINVAL;
1351 }
1352 if (host_err < 0)
1353 goto out_nfserr;
1354
1355 err = nfsd_create_setattr(rqstp, fhp, resfhp, attrs);
1356
1357 out:
1358 dput(dchild);
1359 return err;
1360
1361 out_nfserr:
1362 err = nfserrno(host_err);
1363 goto out;
1364 }
1365
1366 /*
1367 * Create a filesystem object (regular, directory, special).
1368 * Note that the parent directory is left locked.
1369 *
1370 * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp
1371 */
1372 __be32
nfsd_create(struct svc_rqst * rqstp,struct svc_fh * fhp,char * fname,int flen,struct nfsd_attrs * attrs,int type,dev_t rdev,struct svc_fh * resfhp)1373 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
1374 char *fname, int flen, struct nfsd_attrs *attrs,
1375 int type, dev_t rdev, struct svc_fh *resfhp)
1376 {
1377 struct dentry *dentry, *dchild = NULL;
1378 __be32 err;
1379 int host_err;
1380
1381 if (isdotent(fname, flen))
1382 return nfserr_exist;
1383
1384 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP);
1385 if (err)
1386 return err;
1387
1388 dentry = fhp->fh_dentry;
1389
1390 host_err = fh_want_write(fhp);
1391 if (host_err)
1392 return nfserrno(host_err);
1393
1394 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
1395 dchild = lookup_one_len(fname, dentry, flen);
1396 host_err = PTR_ERR(dchild);
1397 if (IS_ERR(dchild)) {
1398 err = nfserrno(host_err);
1399 goto out_unlock;
1400 }
1401 err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
1402 /*
1403 * We unconditionally drop our ref to dchild as fh_compose will have
1404 * already grabbed its own ref for it.
1405 */
1406 dput(dchild);
1407 if (err)
1408 goto out_unlock;
1409 fh_fill_pre_attrs(fhp);
1410 err = nfsd_create_locked(rqstp, fhp, attrs, type, rdev, resfhp);
1411 fh_fill_post_attrs(fhp);
1412 out_unlock:
1413 inode_unlock(dentry->d_inode);
1414 return err;
1415 }
1416
1417 /*
1418 * Read a symlink. On entry, *lenp must contain the maximum path length that
1419 * fits into the buffer. On return, it contains the true length.
1420 * N.B. After this call fhp needs an fh_put
1421 */
1422 __be32
nfsd_readlink(struct svc_rqst * rqstp,struct svc_fh * fhp,char * buf,int * lenp)1423 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
1424 {
1425 __be32 err;
1426 const char *link;
1427 struct path path;
1428 DEFINE_DELAYED_CALL(done);
1429 int len;
1430
1431 err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP);
1432 if (unlikely(err))
1433 return err;
1434
1435 path.mnt = fhp->fh_export->ex_path.mnt;
1436 path.dentry = fhp->fh_dentry;
1437
1438 if (unlikely(!d_is_symlink(path.dentry)))
1439 return nfserr_inval;
1440
1441 touch_atime(&path);
1442
1443 link = vfs_get_link(path.dentry, &done);
1444 if (IS_ERR(link))
1445 return nfserrno(PTR_ERR(link));
1446
1447 len = strlen(link);
1448 if (len < *lenp)
1449 *lenp = len;
1450 memcpy(buf, link, *lenp);
1451 do_delayed_call(&done);
1452 return 0;
1453 }
1454
1455 /**
1456 * nfsd_symlink - Create a symlink and look up its inode
1457 * @rqstp: RPC transaction being executed
1458 * @fhp: NFS filehandle of parent directory
1459 * @fname: filename of the new symlink
1460 * @flen: length of @fname
1461 * @path: content of the new symlink (NUL-terminated)
1462 * @attrs: requested attributes of new object
1463 * @resfhp: NFS filehandle of new object
1464 *
1465 * N.B. After this call _both_ fhp and resfhp need an fh_put
1466 *
1467 * Returns nfs_ok on success, or an nfsstat in network byte order.
1468 */
1469 __be32
nfsd_symlink(struct svc_rqst * rqstp,struct svc_fh * fhp,char * fname,int flen,char * path,struct nfsd_attrs * attrs,struct svc_fh * resfhp)1470 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
1471 char *fname, int flen,
1472 char *path, struct nfsd_attrs *attrs,
1473 struct svc_fh *resfhp)
1474 {
1475 struct dentry *dentry, *dnew;
1476 __be32 err, cerr;
1477 int host_err;
1478
1479 err = nfserr_noent;
1480 if (!flen || path[0] == '\0')
1481 goto out;
1482 err = nfserr_exist;
1483 if (isdotent(fname, flen))
1484 goto out;
1485
1486 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
1487 if (err)
1488 goto out;
1489
1490 host_err = fh_want_write(fhp);
1491 if (host_err) {
1492 err = nfserrno(host_err);
1493 goto out;
1494 }
1495
1496 dentry = fhp->fh_dentry;
1497 inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
1498 dnew = lookup_one_len(fname, dentry, flen);
1499 if (IS_ERR(dnew)) {
1500 err = nfserrno(PTR_ERR(dnew));
1501 inode_unlock(dentry->d_inode);
1502 goto out_drop_write;
1503 }
1504 fh_fill_pre_attrs(fhp);
1505 host_err = vfs_symlink(&init_user_ns, d_inode(dentry), dnew, path);
1506 err = nfserrno(host_err);
1507 cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
1508 if (!err)
1509 nfsd_create_setattr(rqstp, fhp, resfhp, attrs);
1510 fh_fill_post_attrs(fhp);
1511 inode_unlock(dentry->d_inode);
1512 if (!err)
1513 err = nfserrno(commit_metadata(fhp));
1514 dput(dnew);
1515 if (err==0) err = cerr;
1516 out_drop_write:
1517 fh_drop_write(fhp);
1518 out:
1519 return err;
1520 }
1521
1522 /*
1523 * Create a hardlink
1524 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1525 */
1526 __be32
nfsd_link(struct svc_rqst * rqstp,struct svc_fh * ffhp,char * name,int len,struct svc_fh * tfhp)1527 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
1528 char *name, int len, struct svc_fh *tfhp)
1529 {
1530 struct dentry *ddir, *dnew, *dold;
1531 struct inode *dirp;
1532 __be32 err;
1533 int host_err;
1534
1535 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
1536 if (err)
1537 goto out;
1538 err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP);
1539 if (err)
1540 goto out;
1541 err = nfserr_isdir;
1542 if (d_is_dir(tfhp->fh_dentry))
1543 goto out;
1544 err = nfserr_perm;
1545 if (!len)
1546 goto out;
1547 err = nfserr_exist;
1548 if (isdotent(name, len))
1549 goto out;
1550
1551 host_err = fh_want_write(tfhp);
1552 if (host_err) {
1553 err = nfserrno(host_err);
1554 goto out;
1555 }
1556
1557 ddir = ffhp->fh_dentry;
1558 dirp = d_inode(ddir);
1559 inode_lock_nested(dirp, I_MUTEX_PARENT);
1560
1561 dnew = lookup_one_len(name, ddir, len);
1562 if (IS_ERR(dnew)) {
1563 err = nfserrno(PTR_ERR(dnew));
1564 goto out_unlock;
1565 }
1566
1567 dold = tfhp->fh_dentry;
1568
1569 err = nfserr_noent;
1570 if (d_really_is_negative(dold))
1571 goto out_dput;
1572 fh_fill_pre_attrs(ffhp);
1573 host_err = vfs_link(dold, &init_user_ns, dirp, dnew, NULL);
1574 fh_fill_post_attrs(ffhp);
1575 inode_unlock(dirp);
1576 if (!host_err) {
1577 err = nfserrno(commit_metadata(ffhp));
1578 if (!err)
1579 err = nfserrno(commit_metadata(tfhp));
1580 } else {
1581 if (host_err == -EXDEV && rqstp->rq_vers == 2)
1582 err = nfserr_acces;
1583 else
1584 err = nfserrno(host_err);
1585 }
1586 dput(dnew);
1587 out_drop_write:
1588 fh_drop_write(tfhp);
1589 out:
1590 return err;
1591
1592 out_dput:
1593 dput(dnew);
1594 out_unlock:
1595 inode_unlock(dirp);
1596 goto out_drop_write;
1597 }
1598
1599 static void
nfsd_close_cached_files(struct dentry * dentry)1600 nfsd_close_cached_files(struct dentry *dentry)
1601 {
1602 struct inode *inode = d_inode(dentry);
1603
1604 if (inode && S_ISREG(inode->i_mode))
1605 nfsd_file_close_inode_sync(inode);
1606 }
1607
1608 static bool
nfsd_has_cached_files(struct dentry * dentry)1609 nfsd_has_cached_files(struct dentry *dentry)
1610 {
1611 bool ret = false;
1612 struct inode *inode = d_inode(dentry);
1613
1614 if (inode && S_ISREG(inode->i_mode))
1615 ret = nfsd_file_is_cached(inode);
1616 return ret;
1617 }
1618
1619 /*
1620 * Rename a file
1621 * N.B. After this call _both_ ffhp and tfhp need an fh_put
1622 */
1623 __be32
nfsd_rename(struct svc_rqst * rqstp,struct svc_fh * ffhp,char * fname,int flen,struct svc_fh * tfhp,char * tname,int tlen)1624 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
1625 struct svc_fh *tfhp, char *tname, int tlen)
1626 {
1627 struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap;
1628 struct inode *fdir, *tdir;
1629 __be32 err;
1630 int host_err;
1631 bool close_cached = false;
1632
1633 err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE);
1634 if (err)
1635 goto out;
1636 err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE);
1637 if (err)
1638 goto out;
1639
1640 fdentry = ffhp->fh_dentry;
1641 fdir = d_inode(fdentry);
1642
1643 tdentry = tfhp->fh_dentry;
1644 tdir = d_inode(tdentry);
1645
1646 err = nfserr_perm;
1647 if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen))
1648 goto out;
1649
1650 retry:
1651 host_err = fh_want_write(ffhp);
1652 if (host_err) {
1653 err = nfserrno(host_err);
1654 goto out;
1655 }
1656
1657 trap = lock_rename(tdentry, fdentry);
1658 fh_fill_pre_attrs(ffhp);
1659 fh_fill_pre_attrs(tfhp);
1660
1661 odentry = lookup_one_len(fname, fdentry, flen);
1662 host_err = PTR_ERR(odentry);
1663 if (IS_ERR(odentry))
1664 goto out_nfserr;
1665
1666 host_err = -ENOENT;
1667 if (d_really_is_negative(odentry))
1668 goto out_dput_old;
1669 host_err = -EINVAL;
1670 if (odentry == trap)
1671 goto out_dput_old;
1672
1673 ndentry = lookup_one_len(tname, tdentry, tlen);
1674 host_err = PTR_ERR(ndentry);
1675 if (IS_ERR(ndentry))
1676 goto out_dput_old;
1677 host_err = -ENOTEMPTY;
1678 if (ndentry == trap)
1679 goto out_dput_new;
1680
1681 host_err = -EXDEV;
1682 if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
1683 goto out_dput_new;
1684 if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
1685 goto out_dput_new;
1686
1687 if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) &&
1688 nfsd_has_cached_files(ndentry)) {
1689 close_cached = true;
1690 goto out_dput_old;
1691 } else {
1692 struct renamedata rd = {
1693 .old_mnt_userns = &init_user_ns,
1694 .old_dir = fdir,
1695 .old_dentry = odentry,
1696 .new_mnt_userns = &init_user_ns,
1697 .new_dir = tdir,
1698 .new_dentry = ndentry,
1699 };
1700 int retries;
1701
1702 for (retries = 1;;) {
1703 host_err = vfs_rename(&rd);
1704 if (host_err != -EAGAIN || !retries--)
1705 break;
1706 if (!nfsd_wait_for_delegreturn(rqstp, d_inode(odentry)))
1707 break;
1708 }
1709 if (!host_err) {
1710 host_err = commit_metadata(tfhp);
1711 if (!host_err)
1712 host_err = commit_metadata(ffhp);
1713 }
1714 }
1715 out_dput_new:
1716 dput(ndentry);
1717 out_dput_old:
1718 dput(odentry);
1719 out_nfserr:
1720 err = nfserrno(host_err);
1721
1722 if (!close_cached) {
1723 fh_fill_post_attrs(ffhp);
1724 fh_fill_post_attrs(tfhp);
1725 }
1726 unlock_rename(tdentry, fdentry);
1727 fh_drop_write(ffhp);
1728
1729 /*
1730 * If the target dentry has cached open files, then we need to try to
1731 * close them prior to doing the rename. Flushing delayed fput
1732 * shouldn't be done with locks held however, so we delay it until this
1733 * point and then reattempt the whole shebang.
1734 */
1735 if (close_cached) {
1736 close_cached = false;
1737 nfsd_close_cached_files(ndentry);
1738 dput(ndentry);
1739 goto retry;
1740 }
1741 out:
1742 return err;
1743 }
1744
1745 /*
1746 * Unlink a file or directory
1747 * N.B. After this call fhp needs an fh_put
1748 */
1749 __be32
nfsd_unlink(struct svc_rqst * rqstp,struct svc_fh * fhp,int type,char * fname,int flen)1750 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
1751 char *fname, int flen)
1752 {
1753 struct dentry *dentry, *rdentry;
1754 struct inode *dirp;
1755 struct inode *rinode;
1756 __be32 err;
1757 int host_err;
1758
1759 err = nfserr_acces;
1760 if (!flen || isdotent(fname, flen))
1761 goto out;
1762 err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE);
1763 if (err)
1764 goto out;
1765
1766 host_err = fh_want_write(fhp);
1767 if (host_err)
1768 goto out_nfserr;
1769
1770 dentry = fhp->fh_dentry;
1771 dirp = d_inode(dentry);
1772 inode_lock_nested(dirp, I_MUTEX_PARENT);
1773
1774 rdentry = lookup_one_len(fname, dentry, flen);
1775 host_err = PTR_ERR(rdentry);
1776 if (IS_ERR(rdentry))
1777 goto out_unlock;
1778
1779 if (d_really_is_negative(rdentry)) {
1780 dput(rdentry);
1781 host_err = -ENOENT;
1782 goto out_unlock;
1783 }
1784 rinode = d_inode(rdentry);
1785 ihold(rinode);
1786
1787 if (!type)
1788 type = d_inode(rdentry)->i_mode & S_IFMT;
1789
1790 fh_fill_pre_attrs(fhp);
1791 if (type != S_IFDIR) {
1792 int retries;
1793
1794 if (rdentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK)
1795 nfsd_close_cached_files(rdentry);
1796
1797 for (retries = 1;;) {
1798 host_err = vfs_unlink(&init_user_ns, dirp, rdentry, NULL);
1799 if (host_err != -EAGAIN || !retries--)
1800 break;
1801 if (!nfsd_wait_for_delegreturn(rqstp, rinode))
1802 break;
1803 }
1804 } else {
1805 host_err = vfs_rmdir(&init_user_ns, dirp, rdentry);
1806 }
1807 fh_fill_post_attrs(fhp);
1808
1809 inode_unlock(dirp);
1810 if (!host_err)
1811 host_err = commit_metadata(fhp);
1812 dput(rdentry);
1813 iput(rinode); /* truncate the inode here */
1814
1815 out_drop_write:
1816 fh_drop_write(fhp);
1817 out_nfserr:
1818 if (host_err == -EBUSY) {
1819 /* name is mounted-on. There is no perfect
1820 * error status.
1821 */
1822 if (nfsd_v4client(rqstp))
1823 err = nfserr_file_open;
1824 else
1825 err = nfserr_acces;
1826 } else {
1827 err = nfserrno(host_err);
1828 }
1829 out:
1830 return err;
1831 out_unlock:
1832 inode_unlock(dirp);
1833 goto out_drop_write;
1834 }
1835
1836 /*
1837 * We do this buffering because we must not call back into the file
1838 * system's ->lookup() method from the filldir callback. That may well
1839 * deadlock a number of file systems.
1840 *
1841 * This is based heavily on the implementation of same in XFS.
1842 */
1843 struct buffered_dirent {
1844 u64 ino;
1845 loff_t offset;
1846 int namlen;
1847 unsigned int d_type;
1848 char name[];
1849 };
1850
1851 struct readdir_data {
1852 struct dir_context ctx;
1853 char *dirent;
1854 size_t used;
1855 int full;
1856 };
1857
nfsd_buffered_filldir(struct dir_context * ctx,const char * name,int namlen,loff_t offset,u64 ino,unsigned int d_type)1858 static bool nfsd_buffered_filldir(struct dir_context *ctx, const char *name,
1859 int namlen, loff_t offset, u64 ino,
1860 unsigned int d_type)
1861 {
1862 struct readdir_data *buf =
1863 container_of(ctx, struct readdir_data, ctx);
1864 struct buffered_dirent *de = (void *)(buf->dirent + buf->used);
1865 unsigned int reclen;
1866
1867 reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64));
1868 if (buf->used + reclen > PAGE_SIZE) {
1869 buf->full = 1;
1870 return false;
1871 }
1872
1873 de->namlen = namlen;
1874 de->offset = offset;
1875 de->ino = ino;
1876 de->d_type = d_type;
1877 memcpy(de->name, name, namlen);
1878 buf->used += reclen;
1879
1880 return true;
1881 }
1882
nfsd_buffered_readdir(struct file * file,struct svc_fh * fhp,nfsd_filldir_t func,struct readdir_cd * cdp,loff_t * offsetp)1883 static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp,
1884 nfsd_filldir_t func, struct readdir_cd *cdp,
1885 loff_t *offsetp)
1886 {
1887 struct buffered_dirent *de;
1888 int host_err;
1889 int size;
1890 loff_t offset;
1891 struct readdir_data buf = {
1892 .ctx.actor = nfsd_buffered_filldir,
1893 .dirent = (void *)__get_free_page(GFP_KERNEL)
1894 };
1895
1896 if (!buf.dirent)
1897 return nfserrno(-ENOMEM);
1898
1899 offset = *offsetp;
1900
1901 while (1) {
1902 unsigned int reclen;
1903
1904 cdp->err = nfserr_eof; /* will be cleared on successful read */
1905 buf.used = 0;
1906 buf.full = 0;
1907
1908 host_err = iterate_dir(file, &buf.ctx);
1909 if (buf.full)
1910 host_err = 0;
1911
1912 if (host_err < 0)
1913 break;
1914
1915 size = buf.used;
1916
1917 if (!size)
1918 break;
1919
1920 de = (struct buffered_dirent *)buf.dirent;
1921 while (size > 0) {
1922 offset = de->offset;
1923
1924 if (func(cdp, de->name, de->namlen, de->offset,
1925 de->ino, de->d_type))
1926 break;
1927
1928 if (cdp->err != nfs_ok)
1929 break;
1930
1931 trace_nfsd_dirent(fhp, de->ino, de->name, de->namlen);
1932
1933 reclen = ALIGN(sizeof(*de) + de->namlen,
1934 sizeof(u64));
1935 size -= reclen;
1936 de = (struct buffered_dirent *)((char *)de + reclen);
1937 }
1938 if (size > 0) /* We bailed out early */
1939 break;
1940
1941 offset = vfs_llseek(file, 0, SEEK_CUR);
1942 }
1943
1944 free_page((unsigned long)(buf.dirent));
1945
1946 if (host_err)
1947 return nfserrno(host_err);
1948
1949 *offsetp = offset;
1950 return cdp->err;
1951 }
1952
1953 /*
1954 * Read entries from a directory.
1955 * The NFSv3/4 verifier we ignore for now.
1956 */
1957 __be32
nfsd_readdir(struct svc_rqst * rqstp,struct svc_fh * fhp,loff_t * offsetp,struct readdir_cd * cdp,nfsd_filldir_t func)1958 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
1959 struct readdir_cd *cdp, nfsd_filldir_t func)
1960 {
1961 __be32 err;
1962 struct file *file;
1963 loff_t offset = *offsetp;
1964 int may_flags = NFSD_MAY_READ;
1965
1966 /* NFSv2 only supports 32 bit cookies */
1967 if (rqstp->rq_vers > 2)
1968 may_flags |= NFSD_MAY_64BIT_COOKIE;
1969
1970 err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
1971 if (err)
1972 goto out;
1973
1974 offset = vfs_llseek(file, offset, SEEK_SET);
1975 if (offset < 0) {
1976 err = nfserrno((int)offset);
1977 goto out_close;
1978 }
1979
1980 err = nfsd_buffered_readdir(file, fhp, func, cdp, offsetp);
1981
1982 if (err == nfserr_eof || err == nfserr_toosmall)
1983 err = nfs_ok; /* can still be found in ->err */
1984 out_close:
1985 fput(file);
1986 out:
1987 return err;
1988 }
1989
1990 /*
1991 * Get file system stats
1992 * N.B. After this call fhp needs an fh_put
1993 */
1994 __be32
nfsd_statfs(struct svc_rqst * rqstp,struct svc_fh * fhp,struct kstatfs * stat,int access)1995 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
1996 {
1997 __be32 err;
1998
1999 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
2000 if (!err) {
2001 struct path path = {
2002 .mnt = fhp->fh_export->ex_path.mnt,
2003 .dentry = fhp->fh_dentry,
2004 };
2005 if (vfs_statfs(&path, stat))
2006 err = nfserr_io;
2007 }
2008 return err;
2009 }
2010
exp_rdonly(struct svc_rqst * rqstp,struct svc_export * exp)2011 static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
2012 {
2013 return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
2014 }
2015
2016 #ifdef CONFIG_NFSD_V4
2017 /*
2018 * Helper function to translate error numbers. In the case of xattr operations,
2019 * some error codes need to be translated outside of the standard translations.
2020 *
2021 * ENODATA needs to be translated to nfserr_noxattr.
2022 * E2BIG to nfserr_xattr2big.
2023 *
2024 * Additionally, vfs_listxattr can return -ERANGE. This means that the
2025 * file has too many extended attributes to retrieve inside an
2026 * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
2027 * filesystems will allow the adding of extended attributes until they hit
2028 * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
2029 * So, at that point, the attributes are present and valid, but can't
2030 * be retrieved using listxattr, since the upper level xattr code enforces
2031 * the XATTR_LIST_MAX limit.
2032 *
2033 * This bug means that we need to deal with listxattr returning -ERANGE. The
2034 * best mapping is to return TOOSMALL.
2035 */
2036 static __be32
nfsd_xattr_errno(int err)2037 nfsd_xattr_errno(int err)
2038 {
2039 switch (err) {
2040 case -ENODATA:
2041 return nfserr_noxattr;
2042 case -E2BIG:
2043 return nfserr_xattr2big;
2044 case -ERANGE:
2045 return nfserr_toosmall;
2046 }
2047 return nfserrno(err);
2048 }
2049
2050 /*
2051 * Retrieve the specified user extended attribute. To avoid always
2052 * having to allocate the maximum size (since we are not getting
2053 * a maximum size from the RPC), do a probe + alloc. Hold a reader
2054 * lock on i_rwsem to prevent the extended attribute from changing
2055 * size while we're doing this.
2056 */
2057 __be32
nfsd_getxattr(struct svc_rqst * rqstp,struct svc_fh * fhp,char * name,void ** bufp,int * lenp)2058 nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2059 void **bufp, int *lenp)
2060 {
2061 ssize_t len;
2062 __be32 err;
2063 char *buf;
2064 struct inode *inode;
2065 struct dentry *dentry;
2066
2067 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2068 if (err)
2069 return err;
2070
2071 err = nfs_ok;
2072 dentry = fhp->fh_dentry;
2073 inode = d_inode(dentry);
2074
2075 inode_lock_shared(inode);
2076
2077 len = vfs_getxattr(&init_user_ns, dentry, name, NULL, 0);
2078
2079 /*
2080 * Zero-length attribute, just return.
2081 */
2082 if (len == 0) {
2083 *bufp = NULL;
2084 *lenp = 0;
2085 goto out;
2086 }
2087
2088 if (len < 0) {
2089 err = nfsd_xattr_errno(len);
2090 goto out;
2091 }
2092
2093 if (len > *lenp) {
2094 err = nfserr_toosmall;
2095 goto out;
2096 }
2097
2098 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
2099 if (buf == NULL) {
2100 err = nfserr_jukebox;
2101 goto out;
2102 }
2103
2104 len = vfs_getxattr(&init_user_ns, dentry, name, buf, len);
2105 if (len <= 0) {
2106 kvfree(buf);
2107 buf = NULL;
2108 err = nfsd_xattr_errno(len);
2109 }
2110
2111 *lenp = len;
2112 *bufp = buf;
2113
2114 out:
2115 inode_unlock_shared(inode);
2116
2117 return err;
2118 }
2119
2120 /*
2121 * Retrieve the xattr names. Since we can't know how many are
2122 * user extended attributes, we must get all attributes here,
2123 * and have the XDR encode filter out the "user." ones.
2124 *
2125 * While this could always just allocate an XATTR_LIST_MAX
2126 * buffer, that's a waste, so do a probe + allocate. To
2127 * avoid any changes between the probe and allocate, wrap
2128 * this in inode_lock.
2129 */
2130 __be32
nfsd_listxattr(struct svc_rqst * rqstp,struct svc_fh * fhp,char ** bufp,int * lenp)2131 nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp,
2132 int *lenp)
2133 {
2134 ssize_t len;
2135 __be32 err;
2136 char *buf;
2137 struct inode *inode;
2138 struct dentry *dentry;
2139
2140 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
2141 if (err)
2142 return err;
2143
2144 dentry = fhp->fh_dentry;
2145 inode = d_inode(dentry);
2146 *lenp = 0;
2147
2148 inode_lock_shared(inode);
2149
2150 len = vfs_listxattr(dentry, NULL, 0);
2151 if (len <= 0) {
2152 err = nfsd_xattr_errno(len);
2153 goto out;
2154 }
2155
2156 if (len > XATTR_LIST_MAX) {
2157 err = nfserr_xattr2big;
2158 goto out;
2159 }
2160
2161 /*
2162 * We're holding i_rwsem - use GFP_NOFS.
2163 */
2164 buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS);
2165 if (buf == NULL) {
2166 err = nfserr_jukebox;
2167 goto out;
2168 }
2169
2170 len = vfs_listxattr(dentry, buf, len);
2171 if (len <= 0) {
2172 kvfree(buf);
2173 err = nfsd_xattr_errno(len);
2174 goto out;
2175 }
2176
2177 *lenp = len;
2178 *bufp = buf;
2179
2180 err = nfs_ok;
2181 out:
2182 inode_unlock_shared(inode);
2183
2184 return err;
2185 }
2186
2187 /**
2188 * nfsd_removexattr - Remove an extended attribute
2189 * @rqstp: RPC transaction being executed
2190 * @fhp: NFS filehandle of object with xattr to remove
2191 * @name: name of xattr to remove (NUL-terminate)
2192 *
2193 * Pass in a NULL pointer for delegated_inode, and let the client deal
2194 * with NFS4ERR_DELAY (same as with e.g. setattr and remove).
2195 *
2196 * Returns nfs_ok on success, or an nfsstat in network byte order.
2197 */
2198 __be32
nfsd_removexattr(struct svc_rqst * rqstp,struct svc_fh * fhp,char * name)2199 nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
2200 {
2201 __be32 err;
2202 int ret;
2203
2204 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2205 if (err)
2206 return err;
2207
2208 ret = fh_want_write(fhp);
2209 if (ret)
2210 return nfserrno(ret);
2211
2212 inode_lock(fhp->fh_dentry->d_inode);
2213 fh_fill_pre_attrs(fhp);
2214
2215 ret = __vfs_removexattr_locked(&init_user_ns, fhp->fh_dentry,
2216 name, NULL);
2217
2218 fh_fill_post_attrs(fhp);
2219 inode_unlock(fhp->fh_dentry->d_inode);
2220 fh_drop_write(fhp);
2221
2222 return nfsd_xattr_errno(ret);
2223 }
2224
2225 __be32
nfsd_setxattr(struct svc_rqst * rqstp,struct svc_fh * fhp,char * name,void * buf,u32 len,u32 flags)2226 nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
2227 void *buf, u32 len, u32 flags)
2228 {
2229 __be32 err;
2230 int ret;
2231
2232 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
2233 if (err)
2234 return err;
2235
2236 ret = fh_want_write(fhp);
2237 if (ret)
2238 return nfserrno(ret);
2239 inode_lock(fhp->fh_dentry->d_inode);
2240 fh_fill_pre_attrs(fhp);
2241
2242 ret = __vfs_setxattr_locked(&init_user_ns, fhp->fh_dentry, name, buf,
2243 len, flags, NULL);
2244 fh_fill_post_attrs(fhp);
2245 inode_unlock(fhp->fh_dentry->d_inode);
2246 fh_drop_write(fhp);
2247
2248 return nfsd_xattr_errno(ret);
2249 }
2250 #endif
2251
2252 /*
2253 * Check for a user's access permissions to this inode.
2254 */
2255 __be32
nfsd_permission(struct svc_rqst * rqstp,struct svc_export * exp,struct dentry * dentry,int acc)2256 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
2257 struct dentry *dentry, int acc)
2258 {
2259 struct inode *inode = d_inode(dentry);
2260 int err;
2261
2262 if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)
2263 return 0;
2264 #if 0
2265 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
2266 acc,
2267 (acc & NFSD_MAY_READ)? " read" : "",
2268 (acc & NFSD_MAY_WRITE)? " write" : "",
2269 (acc & NFSD_MAY_EXEC)? " exec" : "",
2270 (acc & NFSD_MAY_SATTR)? " sattr" : "",
2271 (acc & NFSD_MAY_TRUNC)? " trunc" : "",
2272 (acc & NFSD_MAY_LOCK)? " lock" : "",
2273 (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "",
2274 inode->i_mode,
2275 IS_IMMUTABLE(inode)? " immut" : "",
2276 IS_APPEND(inode)? " append" : "",
2277 __mnt_is_readonly(exp->ex_path.mnt)? " ro" : "");
2278 dprintk(" owner %d/%d user %d/%d\n",
2279 inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid());
2280 #endif
2281
2282 /* Normally we reject any write/sattr etc access on a read-only file
2283 * system. But if it is IRIX doing check on write-access for a
2284 * device special file, we ignore rofs.
2285 */
2286 if (!(acc & NFSD_MAY_LOCAL_ACCESS))
2287 if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) {
2288 if (exp_rdonly(rqstp, exp) ||
2289 __mnt_is_readonly(exp->ex_path.mnt))
2290 return nfserr_rofs;
2291 if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode))
2292 return nfserr_perm;
2293 }
2294 if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode))
2295 return nfserr_perm;
2296
2297 if (acc & NFSD_MAY_LOCK) {
2298 /* If we cannot rely on authentication in NLM requests,
2299 * just allow locks, otherwise require read permission, or
2300 * ownership
2301 */
2302 if (exp->ex_flags & NFSEXP_NOAUTHNLM)
2303 return 0;
2304 else
2305 acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE;
2306 }
2307 /*
2308 * The file owner always gets access permission for accesses that
2309 * would normally be checked at open time. This is to make
2310 * file access work even when the client has done a fchmod(fd, 0).
2311 *
2312 * However, `cp foo bar' should fail nevertheless when bar is
2313 * readonly. A sensible way to do this might be to reject all
2314 * attempts to truncate a read-only file, because a creat() call
2315 * always implies file truncation.
2316 * ... but this isn't really fair. A process may reasonably call
2317 * ftruncate on an open file descriptor on a file with perm 000.
2318 * We must trust the client to do permission checking - using "ACCESS"
2319 * with NFSv3.
2320 */
2321 if ((acc & NFSD_MAY_OWNER_OVERRIDE) &&
2322 uid_eq(inode->i_uid, current_fsuid()))
2323 return 0;
2324
2325 /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */
2326 err = inode_permission(&init_user_ns, inode,
2327 acc & (MAY_READ | MAY_WRITE | MAY_EXEC));
2328
2329 /* Allow read access to binaries even when mode 111 */
2330 if (err == -EACCES && S_ISREG(inode->i_mode) &&
2331 (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) ||
2332 acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC)))
2333 err = inode_permission(&init_user_ns, inode, MAY_EXEC);
2334
2335 return err? nfserrno(err) : 0;
2336 }
2337