xref: /linux/fs/nfs/nfs4idmap.c (revision 17cfcb68af3bc7d5e8ae08779b1853310a2949f3)
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 <net/net_namespace.h>
40 #include <linux/sunrpc/rpc_pipe_fs.h>
41 #include <linux/nfs_fs.h>
42 #include <linux/nfs_fs_sb.h>
43 #include <linux/key.h>
44 #include <linux/keyctl.h>
45 #include <linux/key-type.h>
46 #include <keys/user-type.h>
47 #include <keys/request_key_auth-type.h>
48 #include <linux/module.h>
49 
50 #include "internal.h"
51 #include "netns.h"
52 #include "nfs4idmap.h"
53 #include "nfs4trace.h"
54 
55 #define NFS_UINT_MAXLEN 11
56 
57 static const struct cred *id_resolver_cache;
58 static struct key_type key_type_id_resolver_legacy;
59 
60 struct idmap_legacy_upcalldata {
61 	struct rpc_pipe_msg pipe_msg;
62 	struct idmap_msg idmap_msg;
63 	struct key	*authkey;
64 	struct idmap *idmap;
65 };
66 
67 struct idmap {
68 	struct rpc_pipe_dir_object idmap_pdo;
69 	struct rpc_pipe		*idmap_pipe;
70 	struct idmap_legacy_upcalldata *idmap_upcall_data;
71 	struct mutex		idmap_mutex;
72 	const struct cred	*cred;
73 };
74 
75 static struct user_namespace *idmap_userns(const struct idmap *idmap)
76 {
77 	if (idmap && idmap->cred)
78 		return idmap->cred->user_ns;
79 	return &init_user_ns;
80 }
81 
82 /**
83  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
84  * @fattr: fully initialised struct nfs_fattr
85  * @owner_name: owner name string cache
86  * @group_name: group name string cache
87  */
88 void nfs_fattr_init_names(struct nfs_fattr *fattr,
89 		struct nfs4_string *owner_name,
90 		struct nfs4_string *group_name)
91 {
92 	fattr->owner_name = owner_name;
93 	fattr->group_name = group_name;
94 }
95 
96 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
97 {
98 	fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
99 	kfree(fattr->owner_name->data);
100 }
101 
102 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
103 {
104 	fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
105 	kfree(fattr->group_name->data);
106 }
107 
108 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
109 {
110 	struct nfs4_string *owner = fattr->owner_name;
111 	kuid_t uid;
112 
113 	if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
114 		return false;
115 	if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
116 		fattr->uid = uid;
117 		fattr->valid |= NFS_ATTR_FATTR_OWNER;
118 	}
119 	return true;
120 }
121 
122 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
123 {
124 	struct nfs4_string *group = fattr->group_name;
125 	kgid_t gid;
126 
127 	if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
128 		return false;
129 	if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
130 		fattr->gid = gid;
131 		fattr->valid |= NFS_ATTR_FATTR_GROUP;
132 	}
133 	return true;
134 }
135 
136 /**
137  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
138  * @fattr: a fully initialised nfs_fattr structure
139  */
140 void nfs_fattr_free_names(struct nfs_fattr *fattr)
141 {
142 	if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
143 		nfs_fattr_free_owner_name(fattr);
144 	if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
145 		nfs_fattr_free_group_name(fattr);
146 }
147 
148 /**
149  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
150  * @server: pointer to the filesystem nfs_server structure
151  * @fattr: a fully initialised nfs_fattr structure
152  *
153  * This helper maps the cached NFSv4 owner/group strings in fattr into
154  * their numeric uid/gid equivalents, and then frees the cached strings.
155  */
156 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
157 {
158 	if (nfs_fattr_map_owner_name(server, fattr))
159 		nfs_fattr_free_owner_name(fattr);
160 	if (nfs_fattr_map_group_name(server, fattr))
161 		nfs_fattr_free_group_name(fattr);
162 }
163 
164 int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
165 {
166 	unsigned long val;
167 	char buf[16];
168 
169 	if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
170 		return 0;
171 	memcpy(buf, name, namelen);
172 	buf[namelen] = '\0';
173 	if (kstrtoul(buf, 0, &val) != 0)
174 		return 0;
175 	*res = val;
176 	return 1;
177 }
178 EXPORT_SYMBOL_GPL(nfs_map_string_to_numeric);
179 
180 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
181 {
182 	return snprintf(buf, buflen, "%u", id);
183 }
184 
185 static struct key_type key_type_id_resolver = {
186 	.name		= "id_resolver",
187 	.preparse	= user_preparse,
188 	.free_preparse	= user_free_preparse,
189 	.instantiate	= generic_key_instantiate,
190 	.revoke		= user_revoke,
191 	.destroy	= user_destroy,
192 	.describe	= user_describe,
193 	.read		= user_read,
194 };
195 
196 int nfs_idmap_init(void)
197 {
198 	struct cred *cred;
199 	struct key *keyring;
200 	int ret = 0;
201 
202 	printk(KERN_NOTICE "NFS: Registering the %s key type\n",
203 		key_type_id_resolver.name);
204 
205 	cred = prepare_kernel_cred(NULL);
206 	if (!cred)
207 		return -ENOMEM;
208 
209 	keyring = keyring_alloc(".id_resolver",
210 				GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
211 				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
212 				KEY_USR_VIEW | KEY_USR_READ,
213 				KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
214 	if (IS_ERR(keyring)) {
215 		ret = PTR_ERR(keyring);
216 		goto failed_put_cred;
217 	}
218 
219 	ret = register_key_type(&key_type_id_resolver);
220 	if (ret < 0)
221 		goto failed_put_key;
222 
223 	ret = register_key_type(&key_type_id_resolver_legacy);
224 	if (ret < 0)
225 		goto failed_reg_legacy;
226 
227 	set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
228 	cred->thread_keyring = keyring;
229 	cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
230 	id_resolver_cache = cred;
231 	return 0;
232 
233 failed_reg_legacy:
234 	unregister_key_type(&key_type_id_resolver);
235 failed_put_key:
236 	key_put(keyring);
237 failed_put_cred:
238 	put_cred(cred);
239 	return ret;
240 }
241 
242 void nfs_idmap_quit(void)
243 {
244 	key_revoke(id_resolver_cache->thread_keyring);
245 	unregister_key_type(&key_type_id_resolver);
246 	unregister_key_type(&key_type_id_resolver_legacy);
247 	put_cred(id_resolver_cache);
248 }
249 
250 /*
251  * Assemble the description to pass to request_key()
252  * This function will allocate a new string and update dest to point
253  * at it.  The caller is responsible for freeing dest.
254  *
255  * On error 0 is returned.  Otherwise, the length of dest is returned.
256  */
257 static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
258 				const char *type, size_t typelen, char **desc)
259 {
260 	char *cp;
261 	size_t desclen = typelen + namelen + 2;
262 
263 	*desc = kmalloc(desclen, GFP_KERNEL);
264 	if (!*desc)
265 		return -ENOMEM;
266 
267 	cp = *desc;
268 	memcpy(cp, type, typelen);
269 	cp += typelen;
270 	*cp++ = ':';
271 
272 	memcpy(cp, name, namelen);
273 	cp += namelen;
274 	*cp = '\0';
275 	return desclen;
276 }
277 
278 static struct key *nfs_idmap_request_key(const char *name, size_t namelen,
279 					 const char *type, struct idmap *idmap)
280 {
281 	char *desc;
282 	struct key *rkey = ERR_PTR(-EAGAIN);
283 	ssize_t ret;
284 
285 	ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
286 	if (ret < 0)
287 		return ERR_PTR(ret);
288 
289 	if (!idmap->cred || idmap->cred->user_ns == &init_user_ns)
290 		rkey = request_key(&key_type_id_resolver, desc, "");
291 	if (IS_ERR(rkey)) {
292 		mutex_lock(&idmap->idmap_mutex);
293 		rkey = request_key_with_auxdata(&key_type_id_resolver_legacy,
294 						desc, NULL, "", 0, idmap);
295 		mutex_unlock(&idmap->idmap_mutex);
296 	}
297 	if (!IS_ERR(rkey))
298 		set_bit(KEY_FLAG_ROOT_CAN_INVAL, &rkey->flags);
299 
300 	kfree(desc);
301 	return rkey;
302 }
303 
304 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
305 				 const char *type, void *data,
306 				 size_t data_size, struct idmap *idmap)
307 {
308 	const struct cred *saved_cred;
309 	struct key *rkey;
310 	const struct user_key_payload *payload;
311 	ssize_t ret;
312 
313 	saved_cred = override_creds(id_resolver_cache);
314 	rkey = nfs_idmap_request_key(name, namelen, type, idmap);
315 	revert_creds(saved_cred);
316 
317 	if (IS_ERR(rkey)) {
318 		ret = PTR_ERR(rkey);
319 		goto out;
320 	}
321 
322 	rcu_read_lock();
323 	rkey->perm |= KEY_USR_VIEW;
324 
325 	ret = key_validate(rkey);
326 	if (ret < 0)
327 		goto out_up;
328 
329 	payload = user_key_payload_rcu(rkey);
330 	if (IS_ERR_OR_NULL(payload)) {
331 		ret = PTR_ERR(payload);
332 		goto out_up;
333 	}
334 
335 	ret = payload->datalen;
336 	if (ret > 0 && ret <= data_size)
337 		memcpy(data, payload->data, ret);
338 	else
339 		ret = -EINVAL;
340 
341 out_up:
342 	rcu_read_unlock();
343 	key_put(rkey);
344 out:
345 	return ret;
346 }
347 
348 /* ID -> Name */
349 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
350 				     size_t buflen, struct idmap *idmap)
351 {
352 	char id_str[NFS_UINT_MAXLEN];
353 	int id_len;
354 	ssize_t ret;
355 
356 	id_len = nfs_map_numeric_to_string(id, id_str, sizeof(id_str));
357 	ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
358 	if (ret < 0)
359 		return -EINVAL;
360 	return ret;
361 }
362 
363 /* Name -> ID */
364 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
365 			       __u32 *id, struct idmap *idmap)
366 {
367 	char id_str[NFS_UINT_MAXLEN];
368 	long id_long;
369 	ssize_t data_size;
370 	int ret = 0;
371 
372 	data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
373 	if (data_size <= 0) {
374 		ret = -EINVAL;
375 	} else {
376 		ret = kstrtol(id_str, 10, &id_long);
377 		if (!ret)
378 			*id = (__u32)id_long;
379 	}
380 	return ret;
381 }
382 
383 /* idmap classic begins here */
384 
385 enum {
386 	Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
387 };
388 
389 static const match_table_t nfs_idmap_tokens = {
390 	{ Opt_find_uid, "uid:%s" },
391 	{ Opt_find_gid, "gid:%s" },
392 	{ Opt_find_user, "user:%s" },
393 	{ Opt_find_group, "group:%s" },
394 	{ Opt_find_err, NULL }
395 };
396 
397 static int nfs_idmap_legacy_upcall(struct key *, void *);
398 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
399 				   size_t);
400 static void idmap_release_pipe(struct inode *);
401 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
402 
403 static const struct rpc_pipe_ops idmap_upcall_ops = {
404 	.upcall		= rpc_pipe_generic_upcall,
405 	.downcall	= idmap_pipe_downcall,
406 	.release_pipe	= idmap_release_pipe,
407 	.destroy_msg	= idmap_pipe_destroy_msg,
408 };
409 
410 static struct key_type key_type_id_resolver_legacy = {
411 	.name		= "id_legacy",
412 	.preparse	= user_preparse,
413 	.free_preparse	= user_free_preparse,
414 	.instantiate	= generic_key_instantiate,
415 	.revoke		= user_revoke,
416 	.destroy	= user_destroy,
417 	.describe	= user_describe,
418 	.read		= user_read,
419 	.request_key	= nfs_idmap_legacy_upcall,
420 };
421 
422 static void nfs_idmap_pipe_destroy(struct dentry *dir,
423 		struct rpc_pipe_dir_object *pdo)
424 {
425 	struct idmap *idmap = pdo->pdo_data;
426 	struct rpc_pipe *pipe = idmap->idmap_pipe;
427 
428 	if (pipe->dentry) {
429 		rpc_unlink(pipe->dentry);
430 		pipe->dentry = NULL;
431 	}
432 }
433 
434 static int nfs_idmap_pipe_create(struct dentry *dir,
435 		struct rpc_pipe_dir_object *pdo)
436 {
437 	struct idmap *idmap = pdo->pdo_data;
438 	struct rpc_pipe *pipe = idmap->idmap_pipe;
439 	struct dentry *dentry;
440 
441 	dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
442 	if (IS_ERR(dentry))
443 		return PTR_ERR(dentry);
444 	pipe->dentry = dentry;
445 	return 0;
446 }
447 
448 static const struct rpc_pipe_dir_object_ops nfs_idmap_pipe_dir_object_ops = {
449 	.create = nfs_idmap_pipe_create,
450 	.destroy = nfs_idmap_pipe_destroy,
451 };
452 
453 int
454 nfs_idmap_new(struct nfs_client *clp)
455 {
456 	struct idmap *idmap;
457 	struct rpc_pipe *pipe;
458 	int error;
459 
460 	idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
461 	if (idmap == NULL)
462 		return -ENOMEM;
463 
464 	mutex_init(&idmap->idmap_mutex);
465 	idmap->cred = get_cred(clp->cl_rpcclient->cl_cred);
466 
467 	rpc_init_pipe_dir_object(&idmap->idmap_pdo,
468 			&nfs_idmap_pipe_dir_object_ops,
469 			idmap);
470 
471 	pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
472 	if (IS_ERR(pipe)) {
473 		error = PTR_ERR(pipe);
474 		goto err;
475 	}
476 	idmap->idmap_pipe = pipe;
477 
478 	error = rpc_add_pipe_dir_object(clp->cl_net,
479 			&clp->cl_rpcclient->cl_pipedir_objects,
480 			&idmap->idmap_pdo);
481 	if (error)
482 		goto err_destroy_pipe;
483 
484 	clp->cl_idmap = idmap;
485 	return 0;
486 err_destroy_pipe:
487 	rpc_destroy_pipe_data(idmap->idmap_pipe);
488 err:
489 	put_cred(idmap->cred);
490 	kfree(idmap);
491 	return error;
492 }
493 
494 void
495 nfs_idmap_delete(struct nfs_client *clp)
496 {
497 	struct idmap *idmap = clp->cl_idmap;
498 
499 	if (!idmap)
500 		return;
501 	clp->cl_idmap = NULL;
502 	rpc_remove_pipe_dir_object(clp->cl_net,
503 			&clp->cl_rpcclient->cl_pipedir_objects,
504 			&idmap->idmap_pdo);
505 	rpc_destroy_pipe_data(idmap->idmap_pipe);
506 	put_cred(idmap->cred);
507 	kfree(idmap);
508 }
509 
510 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
511 				     struct idmap_msg *im,
512 				     struct rpc_pipe_msg *msg)
513 {
514 	substring_t substr;
515 	int token, ret;
516 
517 	im->im_type = IDMAP_TYPE_GROUP;
518 	token = match_token(desc, nfs_idmap_tokens, &substr);
519 
520 	switch (token) {
521 	case Opt_find_uid:
522 		im->im_type = IDMAP_TYPE_USER;
523 		/* Fall through */
524 	case Opt_find_gid:
525 		im->im_conv = IDMAP_CONV_NAMETOID;
526 		ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
527 		break;
528 
529 	case Opt_find_user:
530 		im->im_type = IDMAP_TYPE_USER;
531 		/* Fall through */
532 	case Opt_find_group:
533 		im->im_conv = IDMAP_CONV_IDTONAME;
534 		ret = match_int(&substr, &im->im_id);
535 		if (ret)
536 			goto out;
537 		break;
538 
539 	default:
540 		ret = -EINVAL;
541 		goto out;
542 	}
543 
544 	msg->data = im;
545 	msg->len  = sizeof(struct idmap_msg);
546 
547 out:
548 	return ret;
549 }
550 
551 static bool
552 nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
553 		struct idmap_legacy_upcalldata *data)
554 {
555 	if (idmap->idmap_upcall_data != NULL) {
556 		WARN_ON_ONCE(1);
557 		return false;
558 	}
559 	idmap->idmap_upcall_data = data;
560 	return true;
561 }
562 
563 static void
564 nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
565 {
566 	struct key *authkey = idmap->idmap_upcall_data->authkey;
567 
568 	kfree(idmap->idmap_upcall_data);
569 	idmap->idmap_upcall_data = NULL;
570 	complete_request_key(authkey, ret);
571 	key_put(authkey);
572 }
573 
574 static void
575 nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
576 {
577 	if (idmap->idmap_upcall_data != NULL)
578 		nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
579 }
580 
581 static int nfs_idmap_legacy_upcall(struct key *authkey, void *aux)
582 {
583 	struct idmap_legacy_upcalldata *data;
584 	struct request_key_auth *rka = get_request_key_auth(authkey);
585 	struct rpc_pipe_msg *msg;
586 	struct idmap_msg *im;
587 	struct idmap *idmap = (struct idmap *)aux;
588 	struct key *key = rka->target_key;
589 	int ret = -ENOKEY;
590 
591 	if (!aux)
592 		goto out1;
593 
594 	/* msg and im are freed in idmap_pipe_destroy_msg */
595 	ret = -ENOMEM;
596 	data = kzalloc(sizeof(*data), GFP_KERNEL);
597 	if (!data)
598 		goto out1;
599 
600 	msg = &data->pipe_msg;
601 	im = &data->idmap_msg;
602 	data->idmap = idmap;
603 	data->authkey = key_get(authkey);
604 
605 	ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
606 	if (ret < 0)
607 		goto out2;
608 
609 	ret = -EAGAIN;
610 	if (!nfs_idmap_prepare_pipe_upcall(idmap, data))
611 		goto out2;
612 
613 	ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
614 	if (ret < 0)
615 		nfs_idmap_abort_pipe_upcall(idmap, ret);
616 
617 	return ret;
618 out2:
619 	kfree(data);
620 out1:
621 	complete_request_key(authkey, ret);
622 	return ret;
623 }
624 
625 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
626 {
627 	return key_instantiate_and_link(key, data, datalen,
628 					id_resolver_cache->thread_keyring,
629 					authkey);
630 }
631 
632 static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
633 		struct idmap_msg *upcall,
634 		struct key *key, struct key *authkey)
635 {
636 	char id_str[NFS_UINT_MAXLEN];
637 	size_t len;
638 	int ret = -ENOKEY;
639 
640 	/* ret = -ENOKEY */
641 	if (upcall->im_type != im->im_type || upcall->im_conv != im->im_conv)
642 		goto out;
643 	switch (im->im_conv) {
644 	case IDMAP_CONV_NAMETOID:
645 		if (strcmp(upcall->im_name, im->im_name) != 0)
646 			break;
647 		/* Note: here we store the NUL terminator too */
648 		len = 1 + nfs_map_numeric_to_string(im->im_id, id_str,
649 						    sizeof(id_str));
650 		ret = nfs_idmap_instantiate(key, authkey, id_str, len);
651 		break;
652 	case IDMAP_CONV_IDTONAME:
653 		if (upcall->im_id != im->im_id)
654 			break;
655 		len = strlen(im->im_name);
656 		ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
657 		break;
658 	default:
659 		ret = -EINVAL;
660 	}
661 out:
662 	return ret;
663 }
664 
665 static ssize_t
666 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
667 {
668 	struct request_key_auth *rka;
669 	struct rpc_inode *rpci = RPC_I(file_inode(filp));
670 	struct idmap *idmap = (struct idmap *)rpci->private;
671 	struct key *authkey;
672 	struct idmap_msg im;
673 	size_t namelen_in;
674 	int ret = -ENOKEY;
675 
676 	/* If instantiation is successful, anyone waiting for key construction
677 	 * will have been woken up and someone else may now have used
678 	 * idmap_key_cons - so after this point we may no longer touch it.
679 	 */
680 	if (idmap->idmap_upcall_data == NULL)
681 		goto out_noupcall;
682 
683 	authkey = idmap->idmap_upcall_data->authkey;
684 	rka = get_request_key_auth(authkey);
685 
686 	if (mlen != sizeof(im)) {
687 		ret = -ENOSPC;
688 		goto out;
689 	}
690 
691 	if (copy_from_user(&im, src, mlen) != 0) {
692 		ret = -EFAULT;
693 		goto out;
694 	}
695 
696 	if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
697 		ret = -ENOKEY;
698 		goto out;
699 	}
700 
701 	namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
702 	if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
703 		ret = -EINVAL;
704 		goto out;
705 }
706 
707 	ret = nfs_idmap_read_and_verify_message(&im,
708 			&idmap->idmap_upcall_data->idmap_msg,
709 			rka->target_key, authkey);
710 	if (ret >= 0) {
711 		key_set_timeout(rka->target_key, nfs_idmap_cache_timeout);
712 		ret = mlen;
713 	}
714 
715 out:
716 	nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
717 out_noupcall:
718 	return ret;
719 }
720 
721 static void
722 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
723 {
724 	struct idmap_legacy_upcalldata *data = container_of(msg,
725 			struct idmap_legacy_upcalldata,
726 			pipe_msg);
727 	struct idmap *idmap = data->idmap;
728 
729 	if (msg->errno)
730 		nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
731 }
732 
733 static void
734 idmap_release_pipe(struct inode *inode)
735 {
736 	struct rpc_inode *rpci = RPC_I(inode);
737 	struct idmap *idmap = (struct idmap *)rpci->private;
738 
739 	nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
740 }
741 
742 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)
743 {
744 	struct idmap *idmap = server->nfs_client->cl_idmap;
745 	__u32 id = -1;
746 	int ret = 0;
747 
748 	if (!nfs_map_string_to_numeric(name, namelen, &id))
749 		ret = nfs_idmap_lookup_id(name, namelen, "uid", &id, idmap);
750 	if (ret == 0) {
751 		*uid = make_kuid(idmap_userns(idmap), id);
752 		if (!uid_valid(*uid))
753 			ret = -ERANGE;
754 	}
755 	trace_nfs4_map_name_to_uid(name, namelen, id, ret);
756 	return ret;
757 }
758 
759 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, kgid_t *gid)
760 {
761 	struct idmap *idmap = server->nfs_client->cl_idmap;
762 	__u32 id = -1;
763 	int ret = 0;
764 
765 	if (!nfs_map_string_to_numeric(name, namelen, &id))
766 		ret = nfs_idmap_lookup_id(name, namelen, "gid", &id, idmap);
767 	if (ret == 0) {
768 		*gid = make_kgid(idmap_userns(idmap), id);
769 		if (!gid_valid(*gid))
770 			ret = -ERANGE;
771 	}
772 	trace_nfs4_map_group_to_gid(name, namelen, id, ret);
773 	return ret;
774 }
775 
776 int nfs_map_uid_to_name(const struct nfs_server *server, kuid_t uid, char *buf, size_t buflen)
777 {
778 	struct idmap *idmap = server->nfs_client->cl_idmap;
779 	int ret = -EINVAL;
780 	__u32 id;
781 
782 	id = from_kuid_munged(idmap_userns(idmap), uid);
783 	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
784 		ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
785 	if (ret < 0)
786 		ret = nfs_map_numeric_to_string(id, buf, buflen);
787 	trace_nfs4_map_uid_to_name(buf, ret, id, ret);
788 	return ret;
789 }
790 int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
791 {
792 	struct idmap *idmap = server->nfs_client->cl_idmap;
793 	int ret = -EINVAL;
794 	__u32 id;
795 
796 	id = from_kgid_munged(idmap_userns(idmap), gid);
797 	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
798 		ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
799 	if (ret < 0)
800 		ret = nfs_map_numeric_to_string(id, buf, buflen);
801 	trace_nfs4_map_gid_to_group(buf, ret, id, ret);
802 	return ret;
803 }
804