xref: /linux/fs/nfs/nfs4idmap.c (revision 80d443e8876602be2c130f79c4de81e12e2a700d)
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 <linux/module.h>
48 
49 #include "internal.h"
50 #include "netns.h"
51 #include "nfs4idmap.h"
52 #include "nfs4trace.h"
53 
54 #define NFS_UINT_MAXLEN 11
55 
56 static const struct cred *id_resolver_cache;
57 static struct key_type key_type_id_resolver_legacy;
58 
59 struct idmap_legacy_upcalldata {
60 	struct rpc_pipe_msg pipe_msg;
61 	struct idmap_msg idmap_msg;
62 	struct key_construction	*key_cons;
63 	struct idmap *idmap;
64 };
65 
66 struct idmap {
67 	struct rpc_pipe_dir_object idmap_pdo;
68 	struct rpc_pipe		*idmap_pipe;
69 	struct idmap_legacy_upcalldata *idmap_upcall_data;
70 	struct mutex		idmap_mutex;
71 };
72 
73 /**
74  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
75  * @fattr: fully initialised struct nfs_fattr
76  * @owner_name: owner name string cache
77  * @group_name: group name string cache
78  */
79 void nfs_fattr_init_names(struct nfs_fattr *fattr,
80 		struct nfs4_string *owner_name,
81 		struct nfs4_string *group_name)
82 {
83 	fattr->owner_name = owner_name;
84 	fattr->group_name = group_name;
85 }
86 
87 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
88 {
89 	fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
90 	kfree(fattr->owner_name->data);
91 }
92 
93 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
94 {
95 	fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
96 	kfree(fattr->group_name->data);
97 }
98 
99 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
100 {
101 	struct nfs4_string *owner = fattr->owner_name;
102 	kuid_t uid;
103 
104 	if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
105 		return false;
106 	if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
107 		fattr->uid = uid;
108 		fattr->valid |= NFS_ATTR_FATTR_OWNER;
109 	}
110 	return true;
111 }
112 
113 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
114 {
115 	struct nfs4_string *group = fattr->group_name;
116 	kgid_t gid;
117 
118 	if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
119 		return false;
120 	if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
121 		fattr->gid = gid;
122 		fattr->valid |= NFS_ATTR_FATTR_GROUP;
123 	}
124 	return true;
125 }
126 
127 /**
128  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
129  * @fattr: a fully initialised nfs_fattr structure
130  */
131 void nfs_fattr_free_names(struct nfs_fattr *fattr)
132 {
133 	if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
134 		nfs_fattr_free_owner_name(fattr);
135 	if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
136 		nfs_fattr_free_group_name(fattr);
137 }
138 
139 /**
140  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
141  * @server: pointer to the filesystem nfs_server structure
142  * @fattr: a fully initialised nfs_fattr structure
143  *
144  * This helper maps the cached NFSv4 owner/group strings in fattr into
145  * their numeric uid/gid equivalents, and then frees the cached strings.
146  */
147 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
148 {
149 	if (nfs_fattr_map_owner_name(server, fattr))
150 		nfs_fattr_free_owner_name(fattr);
151 	if (nfs_fattr_map_group_name(server, fattr))
152 		nfs_fattr_free_group_name(fattr);
153 }
154 
155 int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
156 {
157 	unsigned long val;
158 	char buf[16];
159 
160 	if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
161 		return 0;
162 	memcpy(buf, name, namelen);
163 	buf[namelen] = '\0';
164 	if (kstrtoul(buf, 0, &val) != 0)
165 		return 0;
166 	*res = val;
167 	return 1;
168 }
169 EXPORT_SYMBOL_GPL(nfs_map_string_to_numeric);
170 
171 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
172 {
173 	return snprintf(buf, buflen, "%u", id);
174 }
175 
176 static struct key_type key_type_id_resolver = {
177 	.name		= "id_resolver",
178 	.preparse	= user_preparse,
179 	.free_preparse	= user_free_preparse,
180 	.instantiate	= generic_key_instantiate,
181 	.revoke		= user_revoke,
182 	.destroy	= user_destroy,
183 	.describe	= user_describe,
184 	.read		= user_read,
185 };
186 
187 int nfs_idmap_init(void)
188 {
189 	struct cred *cred;
190 	struct key *keyring;
191 	int ret = 0;
192 
193 	printk(KERN_NOTICE "NFS: Registering the %s key type\n",
194 		key_type_id_resolver.name);
195 
196 	cred = prepare_kernel_cred(NULL);
197 	if (!cred)
198 		return -ENOMEM;
199 
200 	keyring = keyring_alloc(".id_resolver",
201 				GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
202 				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
203 				KEY_USR_VIEW | KEY_USR_READ,
204 				KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
205 	if (IS_ERR(keyring)) {
206 		ret = PTR_ERR(keyring);
207 		goto failed_put_cred;
208 	}
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 void nfs_idmap_quit(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 struct key *nfs_idmap_request_key(const char *name, size_t namelen,
270 					 const char *type, struct idmap *idmap)
271 {
272 	char *desc;
273 	struct key *rkey;
274 	ssize_t ret;
275 
276 	ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
277 	if (ret <= 0)
278 		return ERR_PTR(ret);
279 
280 	rkey = request_key(&key_type_id_resolver, desc, "");
281 	if (IS_ERR(rkey)) {
282 		mutex_lock(&idmap->idmap_mutex);
283 		rkey = request_key_with_auxdata(&key_type_id_resolver_legacy,
284 						desc, "", 0, idmap);
285 		mutex_unlock(&idmap->idmap_mutex);
286 	}
287 	if (!IS_ERR(rkey))
288 		set_bit(KEY_FLAG_ROOT_CAN_INVAL, &rkey->flags);
289 
290 	kfree(desc);
291 	return rkey;
292 }
293 
294 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
295 				 const char *type, void *data,
296 				 size_t data_size, struct idmap *idmap)
297 {
298 	const struct cred *saved_cred;
299 	struct key *rkey;
300 	const struct user_key_payload *payload;
301 	ssize_t ret;
302 
303 	saved_cred = override_creds(id_resolver_cache);
304 	rkey = nfs_idmap_request_key(name, namelen, type, idmap);
305 	revert_creds(saved_cred);
306 
307 	if (IS_ERR(rkey)) {
308 		ret = PTR_ERR(rkey);
309 		goto out;
310 	}
311 
312 	rcu_read_lock();
313 	rkey->perm |= KEY_USR_VIEW;
314 
315 	ret = key_validate(rkey);
316 	if (ret < 0)
317 		goto out_up;
318 
319 	payload = user_key_payload(rkey);
320 	if (IS_ERR_OR_NULL(payload)) {
321 		ret = PTR_ERR(payload);
322 		goto out_up;
323 	}
324 
325 	ret = payload->datalen;
326 	if (ret > 0 && ret <= data_size)
327 		memcpy(data, payload->data, ret);
328 	else
329 		ret = -EINVAL;
330 
331 out_up:
332 	rcu_read_unlock();
333 	key_put(rkey);
334 out:
335 	return ret;
336 }
337 
338 /* ID -> Name */
339 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
340 				     size_t buflen, struct idmap *idmap)
341 {
342 	char id_str[NFS_UINT_MAXLEN];
343 	int id_len;
344 	ssize_t ret;
345 
346 	id_len = snprintf(id_str, sizeof(id_str), "%u", id);
347 	ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
348 	if (ret < 0)
349 		return -EINVAL;
350 	return ret;
351 }
352 
353 /* Name -> ID */
354 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
355 			       __u32 *id, struct idmap *idmap)
356 {
357 	char id_str[NFS_UINT_MAXLEN];
358 	long id_long;
359 	ssize_t data_size;
360 	int ret = 0;
361 
362 	data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
363 	if (data_size <= 0) {
364 		ret = -EINVAL;
365 	} else {
366 		ret = kstrtol(id_str, 10, &id_long);
367 		*id = (__u32)id_long;
368 	}
369 	return ret;
370 }
371 
372 /* idmap classic begins here */
373 
374 enum {
375 	Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
376 };
377 
378 static const match_table_t nfs_idmap_tokens = {
379 	{ Opt_find_uid, "uid:%s" },
380 	{ Opt_find_gid, "gid:%s" },
381 	{ Opt_find_user, "user:%s" },
382 	{ Opt_find_group, "group:%s" },
383 	{ Opt_find_err, NULL }
384 };
385 
386 static int nfs_idmap_legacy_upcall(struct key_construction *, const char *, void *);
387 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
388 				   size_t);
389 static void idmap_release_pipe(struct inode *);
390 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
391 
392 static const struct rpc_pipe_ops idmap_upcall_ops = {
393 	.upcall		= rpc_pipe_generic_upcall,
394 	.downcall	= idmap_pipe_downcall,
395 	.release_pipe	= idmap_release_pipe,
396 	.destroy_msg	= idmap_pipe_destroy_msg,
397 };
398 
399 static struct key_type key_type_id_resolver_legacy = {
400 	.name		= "id_legacy",
401 	.preparse	= user_preparse,
402 	.free_preparse	= user_free_preparse,
403 	.instantiate	= generic_key_instantiate,
404 	.revoke		= user_revoke,
405 	.destroy	= user_destroy,
406 	.describe	= user_describe,
407 	.read		= user_read,
408 	.request_key	= nfs_idmap_legacy_upcall,
409 };
410 
411 static void nfs_idmap_pipe_destroy(struct dentry *dir,
412 		struct rpc_pipe_dir_object *pdo)
413 {
414 	struct idmap *idmap = pdo->pdo_data;
415 	struct rpc_pipe *pipe = idmap->idmap_pipe;
416 
417 	if (pipe->dentry) {
418 		rpc_unlink(pipe->dentry);
419 		pipe->dentry = NULL;
420 	}
421 }
422 
423 static int nfs_idmap_pipe_create(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 	struct dentry *dentry;
429 
430 	dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
431 	if (IS_ERR(dentry))
432 		return PTR_ERR(dentry);
433 	pipe->dentry = dentry;
434 	return 0;
435 }
436 
437 static const struct rpc_pipe_dir_object_ops nfs_idmap_pipe_dir_object_ops = {
438 	.create = nfs_idmap_pipe_create,
439 	.destroy = nfs_idmap_pipe_destroy,
440 };
441 
442 int
443 nfs_idmap_new(struct nfs_client *clp)
444 {
445 	struct idmap *idmap;
446 	struct rpc_pipe *pipe;
447 	int error;
448 
449 	idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
450 	if (idmap == NULL)
451 		return -ENOMEM;
452 
453 	rpc_init_pipe_dir_object(&idmap->idmap_pdo,
454 			&nfs_idmap_pipe_dir_object_ops,
455 			idmap);
456 
457 	pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
458 	if (IS_ERR(pipe)) {
459 		error = PTR_ERR(pipe);
460 		goto err;
461 	}
462 	idmap->idmap_pipe = pipe;
463 	mutex_init(&idmap->idmap_mutex);
464 
465 	error = rpc_add_pipe_dir_object(clp->cl_net,
466 			&clp->cl_rpcclient->cl_pipedir_objects,
467 			&idmap->idmap_pdo);
468 	if (error)
469 		goto err_destroy_pipe;
470 
471 	clp->cl_idmap = idmap;
472 	return 0;
473 err_destroy_pipe:
474 	rpc_destroy_pipe_data(idmap->idmap_pipe);
475 err:
476 	kfree(idmap);
477 	return error;
478 }
479 
480 void
481 nfs_idmap_delete(struct nfs_client *clp)
482 {
483 	struct idmap *idmap = clp->cl_idmap;
484 
485 	if (!idmap)
486 		return;
487 	clp->cl_idmap = NULL;
488 	rpc_remove_pipe_dir_object(clp->cl_net,
489 			&clp->cl_rpcclient->cl_pipedir_objects,
490 			&idmap->idmap_pdo);
491 	rpc_destroy_pipe_data(idmap->idmap_pipe);
492 	kfree(idmap);
493 }
494 
495 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
496 				     struct idmap_msg *im,
497 				     struct rpc_pipe_msg *msg)
498 {
499 	substring_t substr;
500 	int token, ret;
501 
502 	im->im_type = IDMAP_TYPE_GROUP;
503 	token = match_token(desc, nfs_idmap_tokens, &substr);
504 
505 	switch (token) {
506 	case Opt_find_uid:
507 		im->im_type = IDMAP_TYPE_USER;
508 	case Opt_find_gid:
509 		im->im_conv = IDMAP_CONV_NAMETOID;
510 		ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
511 		break;
512 
513 	case Opt_find_user:
514 		im->im_type = IDMAP_TYPE_USER;
515 	case Opt_find_group:
516 		im->im_conv = IDMAP_CONV_IDTONAME;
517 		ret = match_int(&substr, &im->im_id);
518 		break;
519 
520 	default:
521 		ret = -EINVAL;
522 		goto out;
523 	}
524 
525 	msg->data = im;
526 	msg->len  = sizeof(struct idmap_msg);
527 
528 out:
529 	return ret;
530 }
531 
532 static bool
533 nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
534 		struct idmap_legacy_upcalldata *data)
535 {
536 	if (idmap->idmap_upcall_data != NULL) {
537 		WARN_ON_ONCE(1);
538 		return false;
539 	}
540 	idmap->idmap_upcall_data = data;
541 	return true;
542 }
543 
544 static void
545 nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
546 {
547 	struct key_construction *cons = idmap->idmap_upcall_data->key_cons;
548 
549 	kfree(idmap->idmap_upcall_data);
550 	idmap->idmap_upcall_data = NULL;
551 	complete_request_key(cons, ret);
552 }
553 
554 static void
555 nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
556 {
557 	if (idmap->idmap_upcall_data != NULL)
558 		nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
559 }
560 
561 static int nfs_idmap_legacy_upcall(struct key_construction *cons,
562 				   const char *op,
563 				   void *aux)
564 {
565 	struct idmap_legacy_upcalldata *data;
566 	struct rpc_pipe_msg *msg;
567 	struct idmap_msg *im;
568 	struct idmap *idmap = (struct idmap *)aux;
569 	struct key *key = cons->key;
570 	int ret = -ENOMEM;
571 
572 	/* msg and im are freed in idmap_pipe_destroy_msg */
573 	data = kzalloc(sizeof(*data), GFP_KERNEL);
574 	if (!data)
575 		goto out1;
576 
577 	msg = &data->pipe_msg;
578 	im = &data->idmap_msg;
579 	data->idmap = idmap;
580 	data->key_cons = cons;
581 
582 	ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
583 	if (ret < 0)
584 		goto out2;
585 
586 	ret = -EAGAIN;
587 	if (!nfs_idmap_prepare_pipe_upcall(idmap, data))
588 		goto out2;
589 
590 	ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
591 	if (ret < 0)
592 		nfs_idmap_abort_pipe_upcall(idmap, ret);
593 
594 	return ret;
595 out2:
596 	kfree(data);
597 out1:
598 	complete_request_key(cons, ret);
599 	return ret;
600 }
601 
602 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
603 {
604 	return key_instantiate_and_link(key, data, datalen,
605 					id_resolver_cache->thread_keyring,
606 					authkey);
607 }
608 
609 static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
610 		struct idmap_msg *upcall,
611 		struct key *key, struct key *authkey)
612 {
613 	char id_str[NFS_UINT_MAXLEN];
614 	size_t len;
615 	int ret = -ENOKEY;
616 
617 	/* ret = -ENOKEY */
618 	if (upcall->im_type != im->im_type || upcall->im_conv != im->im_conv)
619 		goto out;
620 	switch (im->im_conv) {
621 	case IDMAP_CONV_NAMETOID:
622 		if (strcmp(upcall->im_name, im->im_name) != 0)
623 			break;
624 		/* Note: here we store the NUL terminator too */
625 		len = sprintf(id_str, "%d", im->im_id) + 1;
626 		ret = nfs_idmap_instantiate(key, authkey, id_str, len);
627 		break;
628 	case IDMAP_CONV_IDTONAME:
629 		if (upcall->im_id != im->im_id)
630 			break;
631 		len = strlen(im->im_name);
632 		ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
633 		break;
634 	default:
635 		ret = -EINVAL;
636 	}
637 out:
638 	return ret;
639 }
640 
641 static ssize_t
642 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
643 {
644 	struct rpc_inode *rpci = RPC_I(file_inode(filp));
645 	struct idmap *idmap = (struct idmap *)rpci->private;
646 	struct key_construction *cons;
647 	struct idmap_msg im;
648 	size_t namelen_in;
649 	int ret = -ENOKEY;
650 
651 	/* If instantiation is successful, anyone waiting for key construction
652 	 * will have been woken up and someone else may now have used
653 	 * idmap_key_cons - so after this point we may no longer touch it.
654 	 */
655 	if (idmap->idmap_upcall_data == NULL)
656 		goto out_noupcall;
657 
658 	cons = idmap->idmap_upcall_data->key_cons;
659 
660 	if (mlen != sizeof(im)) {
661 		ret = -ENOSPC;
662 		goto out;
663 	}
664 
665 	if (copy_from_user(&im, src, mlen) != 0) {
666 		ret = -EFAULT;
667 		goto out;
668 	}
669 
670 	if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
671 		ret = -ENOKEY;
672 		goto out;
673 	}
674 
675 	namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
676 	if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
677 		ret = -EINVAL;
678 		goto out;
679 }
680 
681 	ret = nfs_idmap_read_and_verify_message(&im,
682 			&idmap->idmap_upcall_data->idmap_msg,
683 			cons->key, cons->authkey);
684 	if (ret >= 0) {
685 		key_set_timeout(cons->key, nfs_idmap_cache_timeout);
686 		ret = mlen;
687 	}
688 
689 out:
690 	nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
691 out_noupcall:
692 	return ret;
693 }
694 
695 static void
696 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
697 {
698 	struct idmap_legacy_upcalldata *data = container_of(msg,
699 			struct idmap_legacy_upcalldata,
700 			pipe_msg);
701 	struct idmap *idmap = data->idmap;
702 
703 	if (msg->errno)
704 		nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
705 }
706 
707 static void
708 idmap_release_pipe(struct inode *inode)
709 {
710 	struct rpc_inode *rpci = RPC_I(inode);
711 	struct idmap *idmap = (struct idmap *)rpci->private;
712 
713 	nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
714 }
715 
716 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)
717 {
718 	struct idmap *idmap = server->nfs_client->cl_idmap;
719 	__u32 id = -1;
720 	int ret = 0;
721 
722 	if (!nfs_map_string_to_numeric(name, namelen, &id))
723 		ret = nfs_idmap_lookup_id(name, namelen, "uid", &id, idmap);
724 	if (ret == 0) {
725 		*uid = make_kuid(&init_user_ns, id);
726 		if (!uid_valid(*uid))
727 			ret = -ERANGE;
728 	}
729 	trace_nfs4_map_name_to_uid(name, namelen, id, ret);
730 	return ret;
731 }
732 
733 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, kgid_t *gid)
734 {
735 	struct idmap *idmap = server->nfs_client->cl_idmap;
736 	__u32 id = -1;
737 	int ret = 0;
738 
739 	if (!nfs_map_string_to_numeric(name, namelen, &id))
740 		ret = nfs_idmap_lookup_id(name, namelen, "gid", &id, idmap);
741 	if (ret == 0) {
742 		*gid = make_kgid(&init_user_ns, id);
743 		if (!gid_valid(*gid))
744 			ret = -ERANGE;
745 	}
746 	trace_nfs4_map_group_to_gid(name, namelen, id, ret);
747 	return ret;
748 }
749 
750 int nfs_map_uid_to_name(const struct nfs_server *server, kuid_t uid, char *buf, size_t buflen)
751 {
752 	struct idmap *idmap = server->nfs_client->cl_idmap;
753 	int ret = -EINVAL;
754 	__u32 id;
755 
756 	id = from_kuid(&init_user_ns, uid);
757 	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
758 		ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
759 	if (ret < 0)
760 		ret = nfs_map_numeric_to_string(id, buf, buflen);
761 	trace_nfs4_map_uid_to_name(buf, ret, id, ret);
762 	return ret;
763 }
764 int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
765 {
766 	struct idmap *idmap = server->nfs_client->cl_idmap;
767 	int ret = -EINVAL;
768 	__u32 id;
769 
770 	id = from_kgid(&init_user_ns, gid);
771 	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
772 		ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
773 	if (ret < 0)
774 		ret = nfs_map_numeric_to_string(id, buf, buflen);
775 	trace_nfs4_map_gid_to_group(buf, ret, id, ret);
776 	return ret;
777 }
778