xref: /linux/fs/nfs/nfs4idmap.c (revision bf80eef2212a1e8451df13b52533f4bc31bb4f8e)
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 #include <linux/user_namespace.h>
50 
51 #include "internal.h"
52 #include "netns.h"
53 #include "nfs4idmap.h"
54 #include "nfs4trace.h"
55 
56 #define NFS_UINT_MAXLEN 11
57 
58 static const struct cred *id_resolver_cache;
59 static struct key_type key_type_id_resolver_legacy;
60 
61 struct idmap_legacy_upcalldata {
62 	struct rpc_pipe_msg pipe_msg;
63 	struct idmap_msg idmap_msg;
64 	struct key	*authkey;
65 	struct idmap *idmap;
66 };
67 
68 struct idmap {
69 	struct rpc_pipe_dir_object idmap_pdo;
70 	struct rpc_pipe		*idmap_pipe;
71 	struct idmap_legacy_upcalldata *idmap_upcall_data;
72 	struct mutex		idmap_mutex;
73 	struct user_namespace	*user_ns;
74 };
75 
76 static struct user_namespace *idmap_userns(const struct idmap *idmap)
77 {
78 	if (idmap && idmap->user_ns)
79 		return idmap->user_ns;
80 	return &init_user_ns;
81 }
82 
83 /**
84  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
85  * @fattr: fully initialised struct nfs_fattr
86  * @owner_name: owner name string cache
87  * @group_name: group name string cache
88  */
89 void nfs_fattr_init_names(struct nfs_fattr *fattr,
90 		struct nfs4_string *owner_name,
91 		struct nfs4_string *group_name)
92 {
93 	fattr->owner_name = owner_name;
94 	fattr->group_name = group_name;
95 }
96 
97 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
98 {
99 	fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
100 	kfree(fattr->owner_name->data);
101 }
102 
103 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
104 {
105 	fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
106 	kfree(fattr->group_name->data);
107 }
108 
109 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
110 {
111 	struct nfs4_string *owner = fattr->owner_name;
112 	kuid_t uid;
113 
114 	if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
115 		return false;
116 	if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
117 		fattr->uid = uid;
118 		fattr->valid |= NFS_ATTR_FATTR_OWNER;
119 	}
120 	return true;
121 }
122 
123 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
124 {
125 	struct nfs4_string *group = fattr->group_name;
126 	kgid_t gid;
127 
128 	if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
129 		return false;
130 	if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
131 		fattr->gid = gid;
132 		fattr->valid |= NFS_ATTR_FATTR_GROUP;
133 	}
134 	return true;
135 }
136 
137 /**
138  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
139  * @fattr: a fully initialised nfs_fattr structure
140  */
141 void nfs_fattr_free_names(struct nfs_fattr *fattr)
142 {
143 	if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
144 		nfs_fattr_free_owner_name(fattr);
145 	if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
146 		nfs_fattr_free_group_name(fattr);
147 }
148 
149 /**
150  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
151  * @server: pointer to the filesystem nfs_server structure
152  * @fattr: a fully initialised nfs_fattr structure
153  *
154  * This helper maps the cached NFSv4 owner/group strings in fattr into
155  * their numeric uid/gid equivalents, and then frees the cached strings.
156  */
157 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
158 {
159 	if (nfs_fattr_map_owner_name(server, fattr))
160 		nfs_fattr_free_owner_name(fattr);
161 	if (nfs_fattr_map_group_name(server, fattr))
162 		nfs_fattr_free_group_name(fattr);
163 }
164 
165 int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
166 {
167 	unsigned long val;
168 	char buf[16];
169 
170 	if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
171 		return 0;
172 	memcpy(buf, name, namelen);
173 	buf[namelen] = '\0';
174 	if (kstrtoul(buf, 0, &val) != 0)
175 		return 0;
176 	*res = val;
177 	return 1;
178 }
179 EXPORT_SYMBOL_GPL(nfs_map_string_to_numeric);
180 
181 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
182 {
183 	return snprintf(buf, buflen, "%u", id);
184 }
185 
186 static struct key_type key_type_id_resolver = {
187 	.name		= "id_resolver",
188 	.preparse	= user_preparse,
189 	.free_preparse	= user_free_preparse,
190 	.instantiate	= generic_key_instantiate,
191 	.revoke		= user_revoke,
192 	.destroy	= user_destroy,
193 	.describe	= user_describe,
194 	.read		= user_read,
195 };
196 
197 int nfs_idmap_init(void)
198 {
199 	struct cred *cred;
200 	struct key *keyring;
201 	int ret = 0;
202 
203 	printk(KERN_NOTICE "NFS: Registering the %s key type\n",
204 		key_type_id_resolver.name);
205 
206 	cred = prepare_kernel_cred(NULL);
207 	if (!cred)
208 		return -ENOMEM;
209 
210 	keyring = keyring_alloc(".id_resolver",
211 				GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
212 				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
213 				KEY_USR_VIEW | KEY_USR_READ,
214 				KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
215 	if (IS_ERR(keyring)) {
216 		ret = PTR_ERR(keyring);
217 		goto failed_put_cred;
218 	}
219 
220 	ret = register_key_type(&key_type_id_resolver);
221 	if (ret < 0)
222 		goto failed_put_key;
223 
224 	ret = register_key_type(&key_type_id_resolver_legacy);
225 	if (ret < 0)
226 		goto failed_reg_legacy;
227 
228 	set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
229 	cred->thread_keyring = keyring;
230 	cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
231 	id_resolver_cache = cred;
232 	return 0;
233 
234 failed_reg_legacy:
235 	unregister_key_type(&key_type_id_resolver);
236 failed_put_key:
237 	key_put(keyring);
238 failed_put_cred:
239 	put_cred(cred);
240 	return ret;
241 }
242 
243 void nfs_idmap_quit(void)
244 {
245 	key_revoke(id_resolver_cache->thread_keyring);
246 	unregister_key_type(&key_type_id_resolver);
247 	unregister_key_type(&key_type_id_resolver_legacy);
248 	put_cred(id_resolver_cache);
249 }
250 
251 /*
252  * Assemble the description to pass to request_key()
253  * This function will allocate a new string and update dest to point
254  * at it.  The caller is responsible for freeing dest.
255  *
256  * On error 0 is returned.  Otherwise, the length of dest is returned.
257  */
258 static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
259 				const char *type, size_t typelen, char **desc)
260 {
261 	char *cp;
262 	size_t desclen = typelen + namelen + 2;
263 
264 	*desc = kmalloc(desclen, GFP_KERNEL);
265 	if (!*desc)
266 		return -ENOMEM;
267 
268 	cp = *desc;
269 	memcpy(cp, type, typelen);
270 	cp += typelen;
271 	*cp++ = ':';
272 
273 	memcpy(cp, name, namelen);
274 	cp += namelen;
275 	*cp = '\0';
276 	return desclen;
277 }
278 
279 static struct key *nfs_idmap_request_key(const char *name, size_t namelen,
280 					 const char *type, struct idmap *idmap)
281 {
282 	char *desc;
283 	struct key *rkey = ERR_PTR(-EAGAIN);
284 	ssize_t ret;
285 
286 	ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
287 	if (ret < 0)
288 		return ERR_PTR(ret);
289 
290 	if (!idmap->user_ns || idmap->user_ns == &init_user_ns)
291 		rkey = request_key(&key_type_id_resolver, desc, "");
292 	if (IS_ERR(rkey)) {
293 		mutex_lock(&idmap->idmap_mutex);
294 		rkey = request_key_with_auxdata(&key_type_id_resolver_legacy,
295 						desc, NULL, "", 0, idmap);
296 		mutex_unlock(&idmap->idmap_mutex);
297 	}
298 	if (!IS_ERR(rkey))
299 		set_bit(KEY_FLAG_ROOT_CAN_INVAL, &rkey->flags);
300 
301 	kfree(desc);
302 	return rkey;
303 }
304 
305 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
306 				 const char *type, void *data,
307 				 size_t data_size, struct idmap *idmap)
308 {
309 	const struct cred *saved_cred;
310 	struct key *rkey;
311 	const struct user_key_payload *payload;
312 	ssize_t ret;
313 
314 	saved_cred = override_creds(id_resolver_cache);
315 	rkey = nfs_idmap_request_key(name, namelen, type, idmap);
316 	revert_creds(saved_cred);
317 
318 	if (IS_ERR(rkey)) {
319 		ret = PTR_ERR(rkey);
320 		goto out;
321 	}
322 
323 	rcu_read_lock();
324 	rkey->perm |= KEY_USR_VIEW;
325 
326 	ret = key_validate(rkey);
327 	if (ret < 0)
328 		goto out_up;
329 
330 	payload = user_key_payload_rcu(rkey);
331 	if (IS_ERR_OR_NULL(payload)) {
332 		ret = PTR_ERR(payload);
333 		goto out_up;
334 	}
335 
336 	ret = payload->datalen;
337 	if (ret > 0 && ret <= data_size)
338 		memcpy(data, payload->data, ret);
339 	else
340 		ret = -EINVAL;
341 
342 out_up:
343 	rcu_read_unlock();
344 	key_put(rkey);
345 out:
346 	return ret;
347 }
348 
349 /* ID -> Name */
350 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
351 				     size_t buflen, struct idmap *idmap)
352 {
353 	char id_str[NFS_UINT_MAXLEN];
354 	int id_len;
355 	ssize_t ret;
356 
357 	id_len = nfs_map_numeric_to_string(id, id_str, sizeof(id_str));
358 	ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
359 	if (ret < 0)
360 		return -EINVAL;
361 	return ret;
362 }
363 
364 /* Name -> ID */
365 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
366 			       __u32 *id, struct idmap *idmap)
367 {
368 	char id_str[NFS_UINT_MAXLEN];
369 	long id_long;
370 	ssize_t data_size;
371 	int ret = 0;
372 
373 	data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
374 	if (data_size <= 0) {
375 		ret = -EINVAL;
376 	} else {
377 		ret = kstrtol(id_str, 10, &id_long);
378 		if (!ret)
379 			*id = (__u32)id_long;
380 	}
381 	return ret;
382 }
383 
384 /* idmap classic begins here */
385 
386 enum {
387 	Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
388 };
389 
390 static const match_table_t nfs_idmap_tokens = {
391 	{ Opt_find_uid, "uid:%s" },
392 	{ Opt_find_gid, "gid:%s" },
393 	{ Opt_find_user, "user:%s" },
394 	{ Opt_find_group, "group:%s" },
395 	{ Opt_find_err, NULL }
396 };
397 
398 static int nfs_idmap_legacy_upcall(struct key *, void *);
399 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
400 				   size_t);
401 static void idmap_release_pipe(struct inode *);
402 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
403 
404 static const struct rpc_pipe_ops idmap_upcall_ops = {
405 	.upcall		= rpc_pipe_generic_upcall,
406 	.downcall	= idmap_pipe_downcall,
407 	.release_pipe	= idmap_release_pipe,
408 	.destroy_msg	= idmap_pipe_destroy_msg,
409 };
410 
411 static struct key_type key_type_id_resolver_legacy = {
412 	.name		= "id_legacy",
413 	.preparse	= user_preparse,
414 	.free_preparse	= user_free_preparse,
415 	.instantiate	= generic_key_instantiate,
416 	.revoke		= user_revoke,
417 	.destroy	= user_destroy,
418 	.describe	= user_describe,
419 	.read		= user_read,
420 	.request_key	= nfs_idmap_legacy_upcall,
421 };
422 
423 static void nfs_idmap_pipe_destroy(struct dentry *dir,
424 		struct rpc_pipe_dir_object *pdo)
425 {
426 	struct idmap *idmap = pdo->pdo_data;
427 	struct rpc_pipe *pipe = idmap->idmap_pipe;
428 
429 	if (pipe->dentry) {
430 		rpc_unlink(pipe->dentry);
431 		pipe->dentry = NULL;
432 	}
433 }
434 
435 static int nfs_idmap_pipe_create(struct dentry *dir,
436 		struct rpc_pipe_dir_object *pdo)
437 {
438 	struct idmap *idmap = pdo->pdo_data;
439 	struct rpc_pipe *pipe = idmap->idmap_pipe;
440 	struct dentry *dentry;
441 
442 	dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
443 	if (IS_ERR(dentry))
444 		return PTR_ERR(dentry);
445 	pipe->dentry = dentry;
446 	return 0;
447 }
448 
449 static const struct rpc_pipe_dir_object_ops nfs_idmap_pipe_dir_object_ops = {
450 	.create = nfs_idmap_pipe_create,
451 	.destroy = nfs_idmap_pipe_destroy,
452 };
453 
454 int
455 nfs_idmap_new(struct nfs_client *clp)
456 {
457 	struct idmap *idmap;
458 	struct rpc_pipe *pipe;
459 	int error;
460 
461 	idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
462 	if (idmap == NULL)
463 		return -ENOMEM;
464 
465 	mutex_init(&idmap->idmap_mutex);
466 	idmap->user_ns = get_user_ns(clp->cl_rpcclient->cl_cred->user_ns);
467 
468 	rpc_init_pipe_dir_object(&idmap->idmap_pdo,
469 			&nfs_idmap_pipe_dir_object_ops,
470 			idmap);
471 
472 	pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
473 	if (IS_ERR(pipe)) {
474 		error = PTR_ERR(pipe);
475 		goto err;
476 	}
477 	idmap->idmap_pipe = pipe;
478 
479 	error = rpc_add_pipe_dir_object(clp->cl_net,
480 			&clp->cl_rpcclient->cl_pipedir_objects,
481 			&idmap->idmap_pdo);
482 	if (error)
483 		goto err_destroy_pipe;
484 
485 	clp->cl_idmap = idmap;
486 	return 0;
487 err_destroy_pipe:
488 	rpc_destroy_pipe_data(idmap->idmap_pipe);
489 err:
490 	put_user_ns(idmap->user_ns);
491 	kfree(idmap);
492 	return error;
493 }
494 
495 void
496 nfs_idmap_delete(struct nfs_client *clp)
497 {
498 	struct idmap *idmap = clp->cl_idmap;
499 
500 	if (!idmap)
501 		return;
502 	clp->cl_idmap = NULL;
503 	rpc_remove_pipe_dir_object(clp->cl_net,
504 			&clp->cl_rpcclient->cl_pipedir_objects,
505 			&idmap->idmap_pdo);
506 	rpc_destroy_pipe_data(idmap->idmap_pipe);
507 	put_user_ns(idmap->user_ns);
508 	kfree(idmap);
509 }
510 
511 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
512 				     struct idmap_msg *im,
513 				     struct rpc_pipe_msg *msg)
514 {
515 	substring_t substr;
516 	int token, ret;
517 
518 	im->im_type = IDMAP_TYPE_GROUP;
519 	token = match_token(desc, nfs_idmap_tokens, &substr);
520 
521 	switch (token) {
522 	case Opt_find_uid:
523 		im->im_type = IDMAP_TYPE_USER;
524 		fallthrough;
525 	case Opt_find_gid:
526 		im->im_conv = IDMAP_CONV_NAMETOID;
527 		ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
528 		break;
529 
530 	case Opt_find_user:
531 		im->im_type = IDMAP_TYPE_USER;
532 		fallthrough;
533 	case Opt_find_group:
534 		im->im_conv = IDMAP_CONV_IDTONAME;
535 		ret = match_int(&substr, &im->im_id);
536 		if (ret)
537 			goto out;
538 		break;
539 
540 	default:
541 		ret = -EINVAL;
542 		goto out;
543 	}
544 
545 	msg->data = im;
546 	msg->len  = sizeof(struct idmap_msg);
547 
548 out:
549 	return ret;
550 }
551 
552 static bool
553 nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
554 		struct idmap_legacy_upcalldata *data)
555 {
556 	if (idmap->idmap_upcall_data != NULL) {
557 		WARN_ON_ONCE(1);
558 		return false;
559 	}
560 	idmap->idmap_upcall_data = data;
561 	return true;
562 }
563 
564 static void nfs_idmap_complete_pipe_upcall(struct idmap_legacy_upcalldata *data,
565 					   int ret)
566 {
567 	complete_request_key(data->authkey, ret);
568 	key_put(data->authkey);
569 	kfree(data);
570 }
571 
572 static void nfs_idmap_abort_pipe_upcall(struct idmap *idmap,
573 					struct idmap_legacy_upcalldata *data,
574 					int ret)
575 {
576 	if (cmpxchg(&idmap->idmap_upcall_data, data, NULL) == data)
577 		nfs_idmap_complete_pipe_upcall(data, ret);
578 }
579 
580 static int nfs_idmap_legacy_upcall(struct key *authkey, void *aux)
581 {
582 	struct idmap_legacy_upcalldata *data;
583 	struct request_key_auth *rka = get_request_key_auth(authkey);
584 	struct rpc_pipe_msg *msg;
585 	struct idmap_msg *im;
586 	struct idmap *idmap = aux;
587 	struct key *key = rka->target_key;
588 	int ret = -ENOKEY;
589 
590 	if (!aux)
591 		goto out1;
592 
593 	/* msg and im are freed in idmap_pipe_destroy_msg */
594 	ret = -ENOMEM;
595 	data = kzalloc(sizeof(*data), GFP_KERNEL);
596 	if (!data)
597 		goto out1;
598 
599 	msg = &data->pipe_msg;
600 	im = &data->idmap_msg;
601 	data->idmap = idmap;
602 	data->authkey = key_get(authkey);
603 
604 	ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
605 	if (ret < 0)
606 		goto out2;
607 
608 	ret = -EAGAIN;
609 	if (!nfs_idmap_prepare_pipe_upcall(idmap, data))
610 		goto out2;
611 
612 	ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
613 	if (ret < 0)
614 		nfs_idmap_abort_pipe_upcall(idmap, data, ret);
615 
616 	return ret;
617 out2:
618 	kfree(data);
619 out1:
620 	complete_request_key(authkey, ret);
621 	return ret;
622 }
623 
624 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
625 {
626 	return key_instantiate_and_link(key, data, datalen,
627 					id_resolver_cache->thread_keyring,
628 					authkey);
629 }
630 
631 static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
632 		struct idmap_msg *upcall,
633 		struct key *key, struct key *authkey)
634 {
635 	char id_str[NFS_UINT_MAXLEN];
636 	size_t len;
637 	int ret = -ENOKEY;
638 
639 	/* ret = -ENOKEY */
640 	if (upcall->im_type != im->im_type || upcall->im_conv != im->im_conv)
641 		goto out;
642 	switch (im->im_conv) {
643 	case IDMAP_CONV_NAMETOID:
644 		if (strcmp(upcall->im_name, im->im_name) != 0)
645 			break;
646 		/* Note: here we store the NUL terminator too */
647 		len = 1 + nfs_map_numeric_to_string(im->im_id, id_str,
648 						    sizeof(id_str));
649 		ret = nfs_idmap_instantiate(key, authkey, id_str, len);
650 		break;
651 	case IDMAP_CONV_IDTONAME:
652 		if (upcall->im_id != im->im_id)
653 			break;
654 		len = strlen(im->im_name);
655 		ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
656 		break;
657 	default:
658 		ret = -EINVAL;
659 	}
660 out:
661 	return ret;
662 }
663 
664 static ssize_t
665 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
666 {
667 	struct request_key_auth *rka;
668 	struct rpc_inode *rpci = RPC_I(file_inode(filp));
669 	struct idmap *idmap = (struct idmap *)rpci->private;
670 	struct idmap_legacy_upcalldata *data;
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 	data = xchg(&idmap->idmap_upcall_data, NULL);
681 	if (data == NULL)
682 		goto out_noupcall;
683 
684 	authkey = data->authkey;
685 	rka = get_request_key_auth(authkey);
686 
687 	if (mlen != sizeof(im)) {
688 		ret = -ENOSPC;
689 		goto out;
690 	}
691 
692 	if (copy_from_user(&im, src, mlen) != 0) {
693 		ret = -EFAULT;
694 		goto out;
695 	}
696 
697 	if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
698 		ret = -ENOKEY;
699 		goto out;
700 	}
701 
702 	namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
703 	if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
704 		ret = -EINVAL;
705 		goto out;
706 	}
707 
708 	ret = nfs_idmap_read_and_verify_message(&im, &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(data, 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, data, 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 	struct idmap_legacy_upcalldata *data;
739 
740 	data = xchg(&idmap->idmap_upcall_data, NULL);
741 	if (data)
742 		nfs_idmap_complete_pipe_upcall(data, -EPIPE);
743 }
744 
745 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)
746 {
747 	struct idmap *idmap = server->nfs_client->cl_idmap;
748 	__u32 id = -1;
749 	int ret = 0;
750 
751 	if (!nfs_map_string_to_numeric(name, namelen, &id))
752 		ret = nfs_idmap_lookup_id(name, namelen, "uid", &id, idmap);
753 	if (ret == 0) {
754 		*uid = make_kuid(idmap_userns(idmap), id);
755 		if (!uid_valid(*uid))
756 			ret = -ERANGE;
757 	}
758 	trace_nfs4_map_name_to_uid(name, namelen, id, ret);
759 	return ret;
760 }
761 
762 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, kgid_t *gid)
763 {
764 	struct idmap *idmap = server->nfs_client->cl_idmap;
765 	__u32 id = -1;
766 	int ret = 0;
767 
768 	if (!nfs_map_string_to_numeric(name, namelen, &id))
769 		ret = nfs_idmap_lookup_id(name, namelen, "gid", &id, idmap);
770 	if (ret == 0) {
771 		*gid = make_kgid(idmap_userns(idmap), id);
772 		if (!gid_valid(*gid))
773 			ret = -ERANGE;
774 	}
775 	trace_nfs4_map_group_to_gid(name, namelen, id, ret);
776 	return ret;
777 }
778 
779 int nfs_map_uid_to_name(const struct nfs_server *server, kuid_t uid, char *buf, size_t buflen)
780 {
781 	struct idmap *idmap = server->nfs_client->cl_idmap;
782 	int ret = -EINVAL;
783 	__u32 id;
784 
785 	id = from_kuid_munged(idmap_userns(idmap), uid);
786 	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
787 		ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
788 	if (ret < 0)
789 		ret = nfs_map_numeric_to_string(id, buf, buflen);
790 	trace_nfs4_map_uid_to_name(buf, ret, id, ret);
791 	return ret;
792 }
793 int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
794 {
795 	struct idmap *idmap = server->nfs_client->cl_idmap;
796 	int ret = -EINVAL;
797 	__u32 id;
798 
799 	id = from_kgid_munged(idmap_userns(idmap), gid);
800 	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
801 		ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
802 	if (ret < 0)
803 		ret = nfs_map_numeric_to_string(id, buf, buflen);
804 	trace_nfs4_map_gid_to_group(buf, ret, id, ret);
805 	return ret;
806 }
807