NFS: Clear key construction data if the idmap upcall fails
[linux-2.6.git] / fs / nfs / idmap.c
1 /*
2  * fs/nfs/idmap.c
3  *
4  *  UID and GID to name mapping for clients.
5  *
6  *  Copyright (c) 2002 The Regents of the University of Michigan.
7  *  All rights reserved.
8  *
9  *  Marius Aamodt Eriksen <marius@umich.edu>
10  *
11  *  Redistribution and use in source and binary forms, with or without
12  *  modification, are permitted provided that the following conditions
13  *  are met:
14  *
15  *  1. Redistributions of source code must retain the above copyright
16  *     notice, this list of conditions and the following disclaimer.
17  *  2. Redistributions in binary form must reproduce the above copyright
18  *     notice, this list of conditions and the following disclaimer in the
19  *     documentation and/or other materials provided with the distribution.
20  *  3. Neither the name of the University nor the names of its
21  *     contributors may be used to endorse or promote products derived
22  *     from this software without specific prior written permission.
23  *
24  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
25  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
27  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
31  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
32  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
33  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
34  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  */
36 #include <linux/types.h>
37 #include <linux/parser.h>
38 #include <linux/fs.h>
39 #include <linux/nfs_idmap.h>
40 #include <net/net_namespace.h>
41 #include <linux/sunrpc/rpc_pipe_fs.h>
42 #include <linux/nfs_fs.h>
43 #include <linux/nfs_fs_sb.h>
44 #include <linux/key.h>
45 #include <linux/keyctl.h>
46 #include <linux/key-type.h>
47 #include <keys/user-type.h>
48 #include <linux/module.h>
49
50 #include "internal.h"
51 #include "netns.h"
52
53 #define NFS_UINT_MAXLEN 11
54
55 /* Default cache timeout is 10 minutes */
56 unsigned int nfs_idmap_cache_timeout = 600;
57 static const struct cred *id_resolver_cache;
58 static struct key_type key_type_id_resolver_legacy;
59
60 struct idmap {
61         struct rpc_pipe         *idmap_pipe;
62         struct key_construction *idmap_key_cons;
63         struct mutex            idmap_mutex;
64 };
65
66 struct idmap_legacy_upcalldata {
67         struct rpc_pipe_msg pipe_msg;
68         struct idmap_msg idmap_msg;
69         struct idmap *idmap;
70 };
71
72 /**
73  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
74  * @fattr: fully initialised struct nfs_fattr
75  * @owner_name: owner name string cache
76  * @group_name: group name string cache
77  */
78 void nfs_fattr_init_names(struct nfs_fattr *fattr,
79                 struct nfs4_string *owner_name,
80                 struct nfs4_string *group_name)
81 {
82         fattr->owner_name = owner_name;
83         fattr->group_name = group_name;
84 }
85
86 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
87 {
88         fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
89         kfree(fattr->owner_name->data);
90 }
91
92 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
93 {
94         fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
95         kfree(fattr->group_name->data);
96 }
97
98 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
99 {
100         struct nfs4_string *owner = fattr->owner_name;
101         __u32 uid;
102
103         if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
104                 return false;
105         if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
106                 fattr->uid = uid;
107                 fattr->valid |= NFS_ATTR_FATTR_OWNER;
108         }
109         return true;
110 }
111
112 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
113 {
114         struct nfs4_string *group = fattr->group_name;
115         __u32 gid;
116
117         if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
118                 return false;
119         if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
120                 fattr->gid = gid;
121                 fattr->valid |= NFS_ATTR_FATTR_GROUP;
122         }
123         return true;
124 }
125
126 /**
127  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
128  * @fattr: a fully initialised nfs_fattr structure
129  */
130 void nfs_fattr_free_names(struct nfs_fattr *fattr)
131 {
132         if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
133                 nfs_fattr_free_owner_name(fattr);
134         if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
135                 nfs_fattr_free_group_name(fattr);
136 }
137
138 /**
139  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
140  * @server: pointer to the filesystem nfs_server structure
141  * @fattr: a fully initialised nfs_fattr structure
142  *
143  * This helper maps the cached NFSv4 owner/group strings in fattr into
144  * their numeric uid/gid equivalents, and then frees the cached strings.
145  */
146 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
147 {
148         if (nfs_fattr_map_owner_name(server, fattr))
149                 nfs_fattr_free_owner_name(fattr);
150         if (nfs_fattr_map_group_name(server, fattr))
151                 nfs_fattr_free_group_name(fattr);
152 }
153
154 static int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
155 {
156         unsigned long val;
157         char buf[16];
158
159         if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
160                 return 0;
161         memcpy(buf, name, namelen);
162         buf[namelen] = '\0';
163         if (strict_strtoul(buf, 0, &val) != 0)
164                 return 0;
165         *res = val;
166         return 1;
167 }
168
169 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
170 {
171         return snprintf(buf, buflen, "%u", id);
172 }
173
174 static struct key_type key_type_id_resolver = {
175         .name           = "id_resolver",
176         .instantiate    = user_instantiate,
177         .match          = user_match,
178         .revoke         = user_revoke,
179         .destroy        = user_destroy,
180         .describe       = user_describe,
181         .read           = user_read,
182 };
183
184 static int nfs_idmap_init_keyring(void)
185 {
186         struct cred *cred;
187         struct key *keyring;
188         int ret = 0;
189
190         printk(KERN_NOTICE "NFS: Registering the %s key type\n",
191                 key_type_id_resolver.name);
192
193         cred = prepare_kernel_cred(NULL);
194         if (!cred)
195                 return -ENOMEM;
196
197         keyring = key_alloc(&key_type_keyring, ".id_resolver", 0, 0, cred,
198                              (KEY_POS_ALL & ~KEY_POS_SETATTR) |
199                              KEY_USR_VIEW | KEY_USR_READ,
200                              KEY_ALLOC_NOT_IN_QUOTA);
201         if (IS_ERR(keyring)) {
202                 ret = PTR_ERR(keyring);
203                 goto failed_put_cred;
204         }
205
206         ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
207         if (ret < 0)
208                 goto failed_put_key;
209
210         ret = register_key_type(&key_type_id_resolver);
211         if (ret < 0)
212                 goto failed_put_key;
213
214         ret = register_key_type(&key_type_id_resolver_legacy);
215         if (ret < 0)
216                 goto failed_reg_legacy;
217
218         set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
219         cred->thread_keyring = keyring;
220         cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
221         id_resolver_cache = cred;
222         return 0;
223
224 failed_reg_legacy:
225         unregister_key_type(&key_type_id_resolver);
226 failed_put_key:
227         key_put(keyring);
228 failed_put_cred:
229         put_cred(cred);
230         return ret;
231 }
232
233 static void nfs_idmap_quit_keyring(void)
234 {
235         key_revoke(id_resolver_cache->thread_keyring);
236         unregister_key_type(&key_type_id_resolver);
237         unregister_key_type(&key_type_id_resolver_legacy);
238         put_cred(id_resolver_cache);
239 }
240
241 /*
242  * Assemble the description to pass to request_key()
243  * This function will allocate a new string and update dest to point
244  * at it.  The caller is responsible for freeing dest.
245  *
246  * On error 0 is returned.  Otherwise, the length of dest is returned.
247  */
248 static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
249                                 const char *type, size_t typelen, char **desc)
250 {
251         char *cp;
252         size_t desclen = typelen + namelen + 2;
253
254         *desc = kmalloc(desclen, GFP_KERNEL);
255         if (!*desc)
256                 return -ENOMEM;
257
258         cp = *desc;
259         memcpy(cp, type, typelen);
260         cp += typelen;
261         *cp++ = ':';
262
263         memcpy(cp, name, namelen);
264         cp += namelen;
265         *cp = '\0';
266         return desclen;
267 }
268
269 static ssize_t nfs_idmap_request_key(struct key_type *key_type,
270                                      const char *name, size_t namelen,
271                                      const char *type, void *data,
272                                      size_t data_size, struct idmap *idmap)
273 {
274         const struct cred *saved_cred;
275         struct key *rkey;
276         char *desc;
277         struct user_key_payload *payload;
278         ssize_t ret;
279
280         ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
281         if (ret <= 0)
282                 goto out;
283
284         saved_cred = override_creds(id_resolver_cache);
285         if (idmap)
286                 rkey = request_key_with_auxdata(key_type, desc, "", 0, idmap);
287         else
288                 rkey = request_key(&key_type_id_resolver, desc, "");
289         revert_creds(saved_cred);
290
291         kfree(desc);
292         if (IS_ERR(rkey)) {
293                 ret = PTR_ERR(rkey);
294                 goto out;
295         }
296
297         rcu_read_lock();
298         rkey->perm |= KEY_USR_VIEW;
299
300         ret = key_validate(rkey);
301         if (ret < 0)
302                 goto out_up;
303
304         payload = rcu_dereference(rkey->payload.data);
305         if (IS_ERR_OR_NULL(payload)) {
306                 ret = PTR_ERR(payload);
307                 goto out_up;
308         }
309
310         ret = payload->datalen;
311         if (ret > 0 && ret <= data_size)
312                 memcpy(data, payload->data, ret);
313         else
314                 ret = -EINVAL;
315
316 out_up:
317         rcu_read_unlock();
318         key_put(rkey);
319 out:
320         return ret;
321 }
322
323 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
324                                  const char *type, void *data,
325                                  size_t data_size, struct idmap *idmap)
326 {
327         ssize_t ret = nfs_idmap_request_key(&key_type_id_resolver,
328                                             name, namelen, type, data,
329                                             data_size, NULL);
330         if (ret < 0) {
331                 mutex_lock(&idmap->idmap_mutex);
332                 ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
333                                             name, namelen, type, data,
334                                             data_size, idmap);
335                 idmap->idmap_key_cons = NULL;
336                 mutex_unlock(&idmap->idmap_mutex);
337         }
338         return ret;
339 }
340
341 /* ID -> Name */
342 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
343                                      size_t buflen, struct idmap *idmap)
344 {
345         char id_str[NFS_UINT_MAXLEN];
346         int id_len;
347         ssize_t ret;
348
349         id_len = snprintf(id_str, sizeof(id_str), "%u", id);
350         ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
351         if (ret < 0)
352                 return -EINVAL;
353         return ret;
354 }
355
356 /* Name -> ID */
357 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
358                                __u32 *id, struct idmap *idmap)
359 {
360         char id_str[NFS_UINT_MAXLEN];
361         long id_long;
362         ssize_t data_size;
363         int ret = 0;
364
365         data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
366         if (data_size <= 0) {
367                 ret = -EINVAL;
368         } else {
369                 ret = strict_strtol(id_str, 10, &id_long);
370                 *id = (__u32)id_long;
371         }
372         return ret;
373 }
374
375 /* idmap classic begins here */
376 module_param(nfs_idmap_cache_timeout, int, 0644);
377
378 enum {
379         Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
380 };
381
382 static const match_table_t nfs_idmap_tokens = {
383         { Opt_find_uid, "uid:%s" },
384         { Opt_find_gid, "gid:%s" },
385         { Opt_find_user, "user:%s" },
386         { Opt_find_group, "group:%s" },
387         { Opt_find_err, NULL }
388 };
389
390 static int nfs_idmap_legacy_upcall(struct key_construction *, const char *, void *);
391 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
392                                    size_t);
393 static void idmap_release_pipe(struct inode *);
394 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
395
396 static const struct rpc_pipe_ops idmap_upcall_ops = {
397         .upcall         = rpc_pipe_generic_upcall,
398         .downcall       = idmap_pipe_downcall,
399         .release_pipe   = idmap_release_pipe,
400         .destroy_msg    = idmap_pipe_destroy_msg,
401 };
402
403 static struct key_type key_type_id_resolver_legacy = {
404         .name           = "id_legacy",
405         .instantiate    = user_instantiate,
406         .match          = user_match,
407         .revoke         = user_revoke,
408         .destroy        = user_destroy,
409         .describe       = user_describe,
410         .read           = user_read,
411         .request_key    = nfs_idmap_legacy_upcall,
412 };
413
414 static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
415 {
416         if (pipe->dentry)
417                 rpc_unlink(pipe->dentry);
418 }
419
420 static int __nfs_idmap_register(struct dentry *dir,
421                                      struct idmap *idmap,
422                                      struct rpc_pipe *pipe)
423 {
424         struct dentry *dentry;
425
426         dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
427         if (IS_ERR(dentry))
428                 return PTR_ERR(dentry);
429         pipe->dentry = dentry;
430         return 0;
431 }
432
433 static void nfs_idmap_unregister(struct nfs_client *clp,
434                                       struct rpc_pipe *pipe)
435 {
436         struct net *net = clp->net;
437         struct super_block *pipefs_sb;
438
439         pipefs_sb = rpc_get_sb_net(net);
440         if (pipefs_sb) {
441                 __nfs_idmap_unregister(pipe);
442                 rpc_put_sb_net(net);
443         }
444 }
445
446 static int nfs_idmap_register(struct nfs_client *clp,
447                                    struct idmap *idmap,
448                                    struct rpc_pipe *pipe)
449 {
450         struct net *net = clp->net;
451         struct super_block *pipefs_sb;
452         int err = 0;
453
454         pipefs_sb = rpc_get_sb_net(net);
455         if (pipefs_sb) {
456                 if (clp->cl_rpcclient->cl_dentry)
457                         err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
458                                                    idmap, pipe);
459                 rpc_put_sb_net(net);
460         }
461         return err;
462 }
463
464 int
465 nfs_idmap_new(struct nfs_client *clp)
466 {
467         struct idmap *idmap;
468         struct rpc_pipe *pipe;
469         int error;
470
471         BUG_ON(clp->cl_idmap != NULL);
472
473         idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
474         if (idmap == NULL)
475                 return -ENOMEM;
476
477         pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
478         if (IS_ERR(pipe)) {
479                 error = PTR_ERR(pipe);
480                 kfree(idmap);
481                 return error;
482         }
483         error = nfs_idmap_register(clp, idmap, pipe);
484         if (error) {
485                 rpc_destroy_pipe_data(pipe);
486                 kfree(idmap);
487                 return error;
488         }
489         idmap->idmap_pipe = pipe;
490         mutex_init(&idmap->idmap_mutex);
491
492         clp->cl_idmap = idmap;
493         return 0;
494 }
495
496 void
497 nfs_idmap_delete(struct nfs_client *clp)
498 {
499         struct idmap *idmap = clp->cl_idmap;
500
501         if (!idmap)
502                 return;
503         nfs_idmap_unregister(clp, idmap->idmap_pipe);
504         rpc_destroy_pipe_data(idmap->idmap_pipe);
505         clp->cl_idmap = NULL;
506         kfree(idmap);
507 }
508
509 static int __rpc_pipefs_event(struct nfs_client *clp, unsigned long event,
510                               struct super_block *sb)
511 {
512         int err = 0;
513
514         switch (event) {
515         case RPC_PIPEFS_MOUNT:
516                 BUG_ON(clp->cl_rpcclient->cl_dentry == NULL);
517                 err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
518                                                 clp->cl_idmap,
519                                                 clp->cl_idmap->idmap_pipe);
520                 break;
521         case RPC_PIPEFS_UMOUNT:
522                 if (clp->cl_idmap->idmap_pipe) {
523                         struct dentry *parent;
524
525                         parent = clp->cl_idmap->idmap_pipe->dentry->d_parent;
526                         __nfs_idmap_unregister(clp->cl_idmap->idmap_pipe);
527                         /*
528                          * Note: This is a dirty hack. SUNRPC hook has been
529                          * called already but simple_rmdir() call for the
530                          * directory returned with error because of idmap pipe
531                          * inside. Thus now we have to remove this directory
532                          * here.
533                          */
534                         if (rpc_rmdir(parent))
535                                 printk(KERN_ERR "NFS: %s: failed to remove "
536                                         "clnt dir!\n", __func__);
537                 }
538                 break;
539         default:
540                 printk(KERN_ERR "NFS: %s: unknown event: %ld\n", __func__,
541                         event);
542                 return -ENOTSUPP;
543         }
544         return err;
545 }
546
547 static struct nfs_client *nfs_get_client_for_event(struct net *net, int event)
548 {
549         struct nfs_net *nn = net_generic(net, nfs_net_id);
550         struct dentry *cl_dentry;
551         struct nfs_client *clp;
552
553         spin_lock(&nn->nfs_client_lock);
554         list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
555                 if (clp->rpc_ops != &nfs_v4_clientops)
556                         continue;
557                 cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
558                 if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) ||
559                     ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
560                         continue;
561                 atomic_inc(&clp->cl_count);
562                 spin_unlock(&nn->nfs_client_lock);
563                 return clp;
564         }
565         spin_unlock(&nn->nfs_client_lock);
566         return NULL;
567 }
568
569 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
570                             void *ptr)
571 {
572         struct super_block *sb = ptr;
573         struct nfs_client *clp;
574         int error = 0;
575
576         if (!try_module_get(THIS_MODULE))
577                 return 0;
578
579         while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
580                 error = __rpc_pipefs_event(clp, event, sb);
581                 nfs_put_client(clp);
582                 if (error)
583                         break;
584         }
585         module_put(THIS_MODULE);
586         return error;
587 }
588
589 #define PIPEFS_NFS_PRIO         1
590
591 static struct notifier_block nfs_idmap_block = {
592         .notifier_call  = rpc_pipefs_event,
593         .priority       = SUNRPC_PIPEFS_NFS_PRIO,
594 };
595
596 int nfs_idmap_init(void)
597 {
598         int ret;
599         ret = nfs_idmap_init_keyring();
600         if (ret != 0)
601                 goto out;
602         ret = rpc_pipefs_notifier_register(&nfs_idmap_block);
603         if (ret != 0)
604                 nfs_idmap_quit_keyring();
605 out:
606         return ret;
607 }
608
609 void nfs_idmap_quit(void)
610 {
611         rpc_pipefs_notifier_unregister(&nfs_idmap_block);
612         nfs_idmap_quit_keyring();
613 }
614
615 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
616                                      struct idmap_msg *im,
617                                      struct rpc_pipe_msg *msg)
618 {
619         substring_t substr;
620         int token, ret;
621
622         memset(im,  0, sizeof(*im));
623         memset(msg, 0, sizeof(*msg));
624
625         im->im_type = IDMAP_TYPE_GROUP;
626         token = match_token(desc, nfs_idmap_tokens, &substr);
627
628         switch (token) {
629         case Opt_find_uid:
630                 im->im_type = IDMAP_TYPE_USER;
631         case Opt_find_gid:
632                 im->im_conv = IDMAP_CONV_NAMETOID;
633                 ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
634                 break;
635
636         case Opt_find_user:
637                 im->im_type = IDMAP_TYPE_USER;
638         case Opt_find_group:
639                 im->im_conv = IDMAP_CONV_IDTONAME;
640                 ret = match_int(&substr, &im->im_id);
641                 break;
642
643         default:
644                 ret = -EINVAL;
645                 goto out;
646         }
647
648         msg->data = im;
649         msg->len  = sizeof(struct idmap_msg);
650
651 out:
652         return ret;
653 }
654
655 static int nfs_idmap_legacy_upcall(struct key_construction *cons,
656                                    const char *op,
657                                    void *aux)
658 {
659         struct idmap_legacy_upcalldata *data;
660         struct rpc_pipe_msg *msg;
661         struct idmap_msg *im;
662         struct idmap *idmap = (struct idmap *)aux;
663         struct key *key = cons->key;
664         int ret = -ENOMEM;
665
666         /* msg and im are freed in idmap_pipe_destroy_msg */
667         data = kmalloc(sizeof(*data), GFP_KERNEL);
668         if (!data)
669                 goto out1;
670
671         msg = &data->pipe_msg;
672         im = &data->idmap_msg;
673         data->idmap = idmap;
674
675         ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
676         if (ret < 0)
677                 goto out2;
678
679         BUG_ON(idmap->idmap_key_cons != NULL);
680         idmap->idmap_key_cons = cons;
681
682         ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
683         if (ret < 0)
684                 goto out3;
685
686         return ret;
687
688 out3:
689         idmap->idmap_key_cons = NULL;
690 out2:
691         kfree(data);
692 out1:
693         complete_request_key(cons, ret);
694         return ret;
695 }
696
697 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data)
698 {
699         return key_instantiate_and_link(key, data, strlen(data) + 1,
700                                         id_resolver_cache->thread_keyring,
701                                         authkey);
702 }
703
704 static int nfs_idmap_read_message(struct idmap_msg *im, struct key *key, struct key *authkey)
705 {
706         char id_str[NFS_UINT_MAXLEN];
707         int ret = -EINVAL;
708
709         switch (im->im_conv) {
710         case IDMAP_CONV_NAMETOID:
711                 sprintf(id_str, "%d", im->im_id);
712                 ret = nfs_idmap_instantiate(key, authkey, id_str);
713                 break;
714         case IDMAP_CONV_IDTONAME:
715                 ret = nfs_idmap_instantiate(key, authkey, im->im_name);
716                 break;
717         }
718
719         return ret;
720 }
721
722 static ssize_t
723 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
724 {
725         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
726         struct idmap *idmap = (struct idmap *)rpci->private;
727         struct key_construction *cons;
728         struct idmap_msg im;
729         size_t namelen_in;
730         int ret;
731
732         /* If instantiation is successful, anyone waiting for key construction
733          * will have been woken up and someone else may now have used
734          * idmap_key_cons - so after this point we may no longer touch it.
735          */
736         cons = ACCESS_ONCE(idmap->idmap_key_cons);
737         idmap->idmap_key_cons = NULL;
738
739         if (mlen != sizeof(im)) {
740                 ret = -ENOSPC;
741                 goto out;
742         }
743
744         if (copy_from_user(&im, src, mlen) != 0) {
745                 ret = -EFAULT;
746                 goto out;
747         }
748
749         if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
750                 ret = mlen;
751                 complete_request_key(cons, -ENOKEY);
752                 goto out_incomplete;
753         }
754
755         namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
756         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
757                 ret = -EINVAL;
758                 goto out;
759         }
760
761         ret = nfs_idmap_read_message(&im, cons->key, cons->authkey);
762         if (ret >= 0) {
763                 key_set_timeout(cons->key, nfs_idmap_cache_timeout);
764                 ret = mlen;
765         }
766
767 out:
768         complete_request_key(cons, ret);
769 out_incomplete:
770         return ret;
771 }
772
773 static void
774 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
775 {
776         struct idmap_legacy_upcalldata *data = container_of(msg,
777                         struct idmap_legacy_upcalldata,
778                         pipe_msg);
779         struct idmap *idmap = data->idmap;
780         struct key_construction *cons;
781         if (msg->errno) {
782                 cons = ACCESS_ONCE(idmap->idmap_key_cons);
783                 idmap->idmap_key_cons = NULL;
784                 complete_request_key(cons, msg->errno);
785         }
786         /* Free memory allocated in nfs_idmap_legacy_upcall() */
787         kfree(data);
788 }
789
790 static void
791 idmap_release_pipe(struct inode *inode)
792 {
793         struct rpc_inode *rpci = RPC_I(inode);
794         struct idmap *idmap = (struct idmap *)rpci->private;
795         idmap->idmap_key_cons = NULL;
796 }
797
798 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *uid)
799 {
800         struct idmap *idmap = server->nfs_client->cl_idmap;
801
802         if (nfs_map_string_to_numeric(name, namelen, uid))
803                 return 0;
804         return nfs_idmap_lookup_id(name, namelen, "uid", uid, idmap);
805 }
806
807 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *gid)
808 {
809         struct idmap *idmap = server->nfs_client->cl_idmap;
810
811         if (nfs_map_string_to_numeric(name, namelen, gid))
812                 return 0;
813         return nfs_idmap_lookup_id(name, namelen, "gid", gid, idmap);
814 }
815
816 int nfs_map_uid_to_name(const struct nfs_server *server, __u32 uid, char *buf, size_t buflen)
817 {
818         struct idmap *idmap = server->nfs_client->cl_idmap;
819         int ret = -EINVAL;
820
821         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
822                 ret = nfs_idmap_lookup_name(uid, "user", buf, buflen, idmap);
823         if (ret < 0)
824                 ret = nfs_map_numeric_to_string(uid, buf, buflen);
825         return ret;
826 }
827 int nfs_map_gid_to_group(const struct nfs_server *server, __u32 gid, char *buf, size_t buflen)
828 {
829         struct idmap *idmap = server->nfs_client->cl_idmap;
830         int ret = -EINVAL;
831
832         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
833                 ret = nfs_idmap_lookup_name(gid, "group", buf, buflen, idmap);
834         if (ret < 0)
835                 ret = nfs_map_numeric_to_string(gid, buf, buflen);
836         return ret;
837 }