[PATCH] knfsd: nfsd: call nfsd_setuser() on fh_compose(), fix nfsd4 permissions problem
[linux-2.6.git] / fs / nfsd / nfsfh.c
1 /*
2  * linux/fs/nfsd/nfsfh.c
3  *
4  * NFS server file handle treatment.
5  *
6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7  * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
8  * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
9  * ... and again Southern-Winter 2001 to support export_operations
10  */
11
12 #include <linux/sched.h>
13 #include <linux/slab.h>
14 #include <linux/smp_lock.h>
15 #include <linux/fs.h>
16 #include <linux/unistd.h>
17 #include <linux/string.h>
18 #include <linux/stat.h>
19 #include <linux/dcache.h>
20 #include <linux/mount.h>
21 #include <asm/pgtable.h>
22
23 #include <linux/sunrpc/svc.h>
24 #include <linux/nfsd/nfsd.h>
25
26 #define NFSDDBG_FACILITY                NFSDDBG_FH
27 #define NFSD_PARANOIA 1
28 /* #define NFSD_DEBUG_VERBOSE 1 */
29
30
31 static int nfsd_nr_verified;
32 static int nfsd_nr_put;
33
34 extern struct export_operations export_op_default;
35
36 #define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
37
38 /*
39  * our acceptability function.
40  * if NOSUBTREECHECK, accept anything
41  * if not, require that we can walk up to exp->ex_dentry
42  * doing some checks on the 'x' bits
43  */
44 static int nfsd_acceptable(void *expv, struct dentry *dentry)
45 {
46         struct svc_export *exp = expv;
47         int rv;
48         struct dentry *tdentry;
49         struct dentry *parent;
50
51         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
52                 return 1;
53
54         tdentry = dget(dentry);
55         while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
56                 /* make sure parents give x permission to user */
57                 int err;
58                 parent = dget_parent(tdentry);
59                 err = permission(parent->d_inode, MAY_EXEC, NULL);
60                 if (err < 0) {
61                         dput(parent);
62                         break;
63                 }
64                 dput(tdentry);
65                 tdentry = parent;
66         }
67         if (tdentry != exp->ex_dentry)
68                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
69         rv = (tdentry == exp->ex_dentry);
70         dput(tdentry);
71         return rv;
72 }
73
74 /* Type check. The correct error return for type mismatches does not seem to be
75  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
76  * comment in the NFSv3 spec says this is incorrect (implementation notes for
77  * the write call).
78  */
79 static inline int
80 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
81 {
82         /* Type can be negative when creating hardlinks - not to a dir */
83         if (type > 0 && (mode & S_IFMT) != type) {
84                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
85                         return nfserr_symlink;
86                 else if (type == S_IFDIR)
87                         return nfserr_notdir;
88                 else if ((mode & S_IFMT) == S_IFDIR)
89                         return nfserr_isdir;
90                 else
91                         return nfserr_inval;
92         }
93         if (type < 0 && (mode & S_IFMT) == -type) {
94                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
95                         return nfserr_symlink;
96                 else if (type == -S_IFDIR)
97                         return nfserr_isdir;
98                 else
99                         return nfserr_notdir;
100         }
101         return 0;
102 }
103
104 /*
105  * Perform sanity checks on the dentry in a client's file handle.
106  *
107  * Note that the file handle dentry may need to be freed even after
108  * an error return.
109  *
110  * This is only called at the start of an nfsproc call, so fhp points to
111  * a svc_fh which is all 0 except for the over-the-wire file handle.
112  */
113 u32
114 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
115 {
116         struct knfsd_fh *fh = &fhp->fh_handle;
117         struct svc_export *exp = NULL;
118         struct dentry   *dentry;
119         u32             error = 0;
120
121         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
122
123         /* keep this filehandle for possible reference  when encoding attributes */
124         rqstp->rq_reffh = fh;
125
126         if (!fhp->fh_dentry) {
127                 __u32 *datap=NULL;
128                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
129                 int fileid_type;
130                 int data_left = fh->fh_size/4;
131
132                 error = nfserr_stale;
133                 if (rqstp->rq_client == NULL)
134                         goto out;
135                 if (rqstp->rq_vers > 2)
136                         error = nfserr_badhandle;
137                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
138                         return nfserr_nofilehandle;
139
140                 if (fh->fh_version == 1) {
141                         int len;
142                         datap = fh->fh_auth;
143                         if (--data_left<0) goto out;
144                         switch (fh->fh_auth_type) {
145                         case 0: break;
146                         default: goto out;
147                         }
148                         len = key_len(fh->fh_fsid_type) / 4;
149                         if (len == 0) goto out;
150                         if  (fh->fh_fsid_type == 2) {
151                                 /* deprecated, convert to type 3 */
152                                 len = 3;
153                                 fh->fh_fsid_type = 3;
154                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
155                                 fh->fh_fsid[1] = fh->fh_fsid[2];
156                         }
157                         if ((data_left -= len)<0) goto out;
158                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
159                         datap += len;
160                 } else {
161                         dev_t xdev;
162                         ino_t xino;
163                         if (fh->fh_size != NFS_FHSIZE)
164                                 goto out;
165                         /* assume old filehandle format */
166                         xdev = old_decode_dev(fh->ofh_xdev);
167                         xino = u32_to_ino_t(fh->ofh_xino);
168                         mk_fsid_v0(tfh, xdev, xino);
169                         exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle);
170                 }
171
172                 error = nfserr_dropit;
173                 if (IS_ERR(exp) && PTR_ERR(exp) == -EAGAIN)
174                         goto out;
175
176                 error = nfserr_stale; 
177                 if (!exp || IS_ERR(exp))
178                         goto out;
179
180                 /* Check if the request originated from a secure port. */
181                 error = nfserr_perm;
182                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
183                         printk(KERN_WARNING
184                                "nfsd: request from insecure port (%u.%u.%u.%u:%d)!\n",
185                                NIPQUAD(rqstp->rq_addr.sin_addr.s_addr),
186                                ntohs(rqstp->rq_addr.sin_port));
187                         goto out;
188                 }
189
190                 /*
191                  * Look up the dentry using the NFS file handle.
192                  */
193                 error = nfserr_stale;
194                 if (rqstp->rq_vers > 2)
195                         error = nfserr_badhandle;
196
197                 if (fh->fh_version != 1) {
198                         tfh[0] = fh->ofh_ino;
199                         tfh[1] = fh->ofh_generation;
200                         tfh[2] = fh->ofh_dirino;
201                         datap = tfh;
202                         data_left = 3;
203                         if (fh->ofh_dirino == 0)
204                                 fileid_type = 1;
205                         else
206                                 fileid_type = 2;
207                 } else
208                         fileid_type = fh->fh_fileid_type;
209                 
210                 if (fileid_type == 0)
211                         dentry = dget(exp->ex_dentry);
212                 else {
213                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
214                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
215                                                      datap, data_left,
216                                                      fileid_type,
217                                                      nfsd_acceptable, exp);
218                 }
219                 if (dentry == NULL)
220                         goto out;
221                 if (IS_ERR(dentry)) {
222                         if (PTR_ERR(dentry) != -EINVAL)
223                                 error = nfserrno(PTR_ERR(dentry));
224                         goto out;
225                 }
226 #ifdef NFSD_PARANOIA
227                 if (S_ISDIR(dentry->d_inode->i_mode) &&
228                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
229                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
230                                dentry->d_parent->d_name.name, dentry->d_name.name);
231                 }
232 #endif
233
234                 fhp->fh_dentry = dentry;
235                 fhp->fh_export = exp;
236                 nfsd_nr_verified++;
237         } else {
238                 /* just rechecking permissions
239                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
240                  */
241                 dprintk("nfsd: fh_verify - just checking\n");
242                 dentry = fhp->fh_dentry;
243                 exp = fhp->fh_export;
244         }
245         cache_get(&exp->h);
246
247         /* Set user creds for this exportpoint; necessary even in the "just
248          * checking" case because this may be a filehandle that was created by
249          * fh_compose, and that is about to be used in another nfsv4 compound
250          * operation */
251         error = nfserrno(nfsd_setuser(rqstp, exp));
252         if (error)
253                 goto out;
254
255         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
256         if (error)
257                 goto out;
258
259         /* Finally, check access permissions. */
260         error = nfsd_permission(exp, dentry, access);
261
262 #ifdef NFSD_PARANOIA_EXTREME
263         if (error) {
264                 printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n",
265                        dentry->d_parent->d_name.name, dentry->d_name.name, access, (error >> 24));
266         }
267 #endif
268 out:
269         if (exp && !IS_ERR(exp))
270                 exp_put(exp);
271         if (error == nfserr_stale)
272                 nfsdstats.fh_stale++;
273         return error;
274 }
275
276
277 /*
278  * Compose a file handle for an NFS reply.
279  *
280  * Note that when first composed, the dentry may not yet have
281  * an inode.  In this case a call to fh_update should be made
282  * before the fh goes out on the wire ...
283  */
284 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
285                              __u32 *datap, int *maxsize)
286 {
287         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
288         
289         if (dentry == exp->ex_dentry) {
290                 *maxsize = 0;
291                 return 0;
292         }
293
294         return CALL(nop,encode_fh)(dentry, datap, maxsize,
295                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
296 }
297
298 /*
299  * for composing old style file handles
300  */
301 static inline void _fh_update_old(struct dentry *dentry,
302                                   struct svc_export *exp,
303                                   struct knfsd_fh *fh)
304 {
305         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
306         fh->ofh_generation = dentry->d_inode->i_generation;
307         if (S_ISDIR(dentry->d_inode->i_mode) ||
308             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
309                 fh->ofh_dirino = 0;
310 }
311
312 int
313 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, struct svc_fh *ref_fh)
314 {
315         /* ref_fh is a reference file handle.
316          * if it is non-null and for the same filesystem, then we should compose
317          * a filehandle which is of the same version, where possible.
318          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
319          * Then create a 32byte filehandle using nfs_fhbase_old
320          *
321          */
322
323         u8 ref_fh_version = 0;
324         u8 ref_fh_fsid_type = 0;
325         struct inode * inode = dentry->d_inode;
326         struct dentry *parent = dentry->d_parent;
327         __u32 *datap;
328         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
329
330         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
331                 MAJOR(ex_dev), MINOR(ex_dev),
332                 (long) exp->ex_dentry->d_inode->i_ino,
333                 parent->d_name.name, dentry->d_name.name,
334                 (inode ? inode->i_ino : 0));
335
336         if (ref_fh && ref_fh->fh_export == exp) {
337                 ref_fh_version = ref_fh->fh_handle.fh_version;
338                 if (ref_fh_version == 0xca)
339                         ref_fh_fsid_type = 0;
340                 else
341                         ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type;
342                 if (ref_fh_fsid_type > 3)
343                         ref_fh_fsid_type = 0;
344
345                 /* make sure ref_fh type works for given export */
346                 if (ref_fh_fsid_type == 1 &&
347                     !(exp->ex_flags & NFSEXP_FSID)) {
348                         /* if we don't have an fsid, we cannot provide one... */
349                         ref_fh_fsid_type = 0;
350                 }
351         } else if (exp->ex_flags & NFSEXP_FSID)
352                 ref_fh_fsid_type = 1;
353
354         if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) {
355                 /* for newer device numbers, we must use a newer fsid format */
356                 ref_fh_version = 1;
357                 ref_fh_fsid_type = 3;
358         }
359         if (old_valid_dev(ex_dev) &&
360             (ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3))
361                 /* must use type1 for smaller device numbers */
362                 ref_fh_fsid_type = 0;
363
364         if (ref_fh == fhp)
365                 fh_put(ref_fh);
366
367         if (fhp->fh_locked || fhp->fh_dentry) {
368                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
369                         parent->d_name.name, dentry->d_name.name);
370         }
371         if (fhp->fh_maxsize < NFS_FHSIZE)
372                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
373                        fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);
374
375         fhp->fh_dentry = dget(dentry); /* our internal copy */
376         fhp->fh_export = exp;
377         cache_get(&exp->h);
378
379         if (ref_fh_version == 0xca) {
380                 /* old style filehandle please */
381                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
382                 fhp->fh_handle.fh_size = NFS_FHSIZE;
383                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
384                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
385                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
386                 fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
387                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
388                 if (inode)
389                         _fh_update_old(dentry, exp, &fhp->fh_handle);
390         } else {
391                 int len;
392                 fhp->fh_handle.fh_version = 1;
393                 fhp->fh_handle.fh_auth_type = 0;
394                 datap = fhp->fh_handle.fh_auth+0;
395                 fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type;
396                 switch (ref_fh_fsid_type) {
397                         case 0:
398                                 /*
399                                  * fsid_type 0:
400                                  * 2byte major, 2byte minor, 4byte inode
401                                  */
402                                 mk_fsid_v0(datap, ex_dev,
403                                         exp->ex_dentry->d_inode->i_ino);
404                                 break;
405                         case 1:
406                                 /* fsid_type 1 == 4 bytes filesystem id */
407                                 mk_fsid_v1(datap, exp->ex_fsid);
408                                 break;
409                         case 2:
410                                 /*
411                                  * fsid_type 2:
412                                  * 4byte major, 4byte minor, 4byte inode
413                                  */
414                                 mk_fsid_v2(datap, ex_dev,
415                                         exp->ex_dentry->d_inode->i_ino);
416                                 break;
417                         case 3:
418                                 /*
419                                  * fsid_type 3:
420                                  * 4byte devicenumber, 4byte inode
421                                  */
422                                 mk_fsid_v3(datap, ex_dev,
423                                         exp->ex_dentry->d_inode->i_ino);
424                                 break;
425                 }
426                 len = key_len(ref_fh_fsid_type);
427                 datap += len/4;
428                 fhp->fh_handle.fh_size = 4 + len;
429
430                 if (inode) {
431                         int size = (fhp->fh_maxsize-len-4)/4;
432                         fhp->fh_handle.fh_fileid_type =
433                                 _fh_update(dentry, exp, datap, &size);
434                         fhp->fh_handle.fh_size += size*4;
435                 }
436                 if (fhp->fh_handle.fh_fileid_type == 255)
437                         return nfserr_opnotsupp;
438         }
439
440         nfsd_nr_verified++;
441         return 0;
442 }
443
444 /*
445  * Update file handle information after changing a dentry.
446  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
447  */
448 int
449 fh_update(struct svc_fh *fhp)
450 {
451         struct dentry *dentry;
452         __u32 *datap;
453         
454         if (!fhp->fh_dentry)
455                 goto out_bad;
456
457         dentry = fhp->fh_dentry;
458         if (!dentry->d_inode)
459                 goto out_negative;
460         if (fhp->fh_handle.fh_version != 1) {
461                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
462         } else {
463                 int size;
464                 if (fhp->fh_handle.fh_fileid_type != 0)
465                         goto out;
466                 datap = fhp->fh_handle.fh_auth+
467                         fhp->fh_handle.fh_size/4 -1;
468                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
469                 fhp->fh_handle.fh_fileid_type =
470                         _fh_update(dentry, fhp->fh_export, datap, &size);
471                 fhp->fh_handle.fh_size += size*4;
472                 if (fhp->fh_handle.fh_fileid_type == 255)
473                         return nfserr_opnotsupp;
474         }
475 out:
476         return 0;
477
478 out_bad:
479         printk(KERN_ERR "fh_update: fh not verified!\n");
480         goto out;
481 out_negative:
482         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
483                 dentry->d_parent->d_name.name, dentry->d_name.name);
484         goto out;
485 }
486
487 /*
488  * Release a file handle.
489  */
490 void
491 fh_put(struct svc_fh *fhp)
492 {
493         struct dentry * dentry = fhp->fh_dentry;
494         struct svc_export * exp = fhp->fh_export;
495         if (dentry) {
496                 fh_unlock(fhp);
497                 fhp->fh_dentry = NULL;
498                 dput(dentry);
499 #ifdef CONFIG_NFSD_V3
500                 fhp->fh_pre_saved = 0;
501                 fhp->fh_post_saved = 0;
502 #endif
503                 nfsd_nr_put++;
504         }
505         if (exp) {
506                 cache_put(&exp->h, &svc_export_cache);
507                 fhp->fh_export = NULL;
508         }
509         return;
510 }
511
512 /*
513  * Shorthand for dprintk()'s
514  */
515 char * SVCFH_fmt(struct svc_fh *fhp)
516 {
517         struct knfsd_fh *fh = &fhp->fh_handle;
518
519         static char buf[80];
520         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
521                 fh->fh_size,
522                 fh->fh_base.fh_pad[0],
523                 fh->fh_base.fh_pad[1],
524                 fh->fh_base.fh_pad[2],
525                 fh->fh_base.fh_pad[3],
526                 fh->fh_base.fh_pad[4],
527                 fh->fh_base.fh_pad[5]);
528         return buf;
529 }