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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 static const struct cred *id_resolver_cache;
56 static struct key_type key_type_id_resolver_legacy;
57 
58 struct idmap_legacy_upcalldata {
59 	struct rpc_pipe_msg pipe_msg;
60 	struct idmap_msg idmap_msg;
61 	struct key_construction	*key_cons;
62 	struct idmap *idmap;
63 };
64 
65 struct idmap {
66 	struct rpc_pipe		*idmap_pipe;
67 	struct idmap_legacy_upcalldata *idmap_upcall_data;
68 	struct mutex		idmap_mutex;
69 };
70 
71 /**
72  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
73  * @fattr: fully initialised struct nfs_fattr
74  * @owner_name: owner name string cache
75  * @group_name: group name string cache
76  */
nfs_fattr_init_names(struct nfs_fattr * fattr,struct nfs4_string * owner_name,struct nfs4_string * group_name)77 void nfs_fattr_init_names(struct nfs_fattr *fattr,
78 		struct nfs4_string *owner_name,
79 		struct nfs4_string *group_name)
80 {
81 	fattr->owner_name = owner_name;
82 	fattr->group_name = group_name;
83 }
84 
nfs_fattr_free_owner_name(struct nfs_fattr * fattr)85 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
86 {
87 	fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
88 	kfree(fattr->owner_name->data);
89 }
90 
nfs_fattr_free_group_name(struct nfs_fattr * fattr)91 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
92 {
93 	fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
94 	kfree(fattr->group_name->data);
95 }
96 
nfs_fattr_map_owner_name(struct nfs_server * server,struct nfs_fattr * fattr)97 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
98 {
99 	struct nfs4_string *owner = fattr->owner_name;
100 	kuid_t uid;
101 
102 	if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
103 		return false;
104 	if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
105 		fattr->uid = uid;
106 		fattr->valid |= NFS_ATTR_FATTR_OWNER;
107 	}
108 	return true;
109 }
110 
nfs_fattr_map_group_name(struct nfs_server * server,struct nfs_fattr * fattr)111 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
112 {
113 	struct nfs4_string *group = fattr->group_name;
114 	kgid_t gid;
115 
116 	if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
117 		return false;
118 	if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
119 		fattr->gid = gid;
120 		fattr->valid |= NFS_ATTR_FATTR_GROUP;
121 	}
122 	return true;
123 }
124 
125 /**
126  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
127  * @fattr: a fully initialised nfs_fattr structure
128  */
nfs_fattr_free_names(struct nfs_fattr * fattr)129 void nfs_fattr_free_names(struct nfs_fattr *fattr)
130 {
131 	if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
132 		nfs_fattr_free_owner_name(fattr);
133 	if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
134 		nfs_fattr_free_group_name(fattr);
135 }
136 
137 /**
138  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
139  * @server: pointer to the filesystem nfs_server structure
140  * @fattr: a fully initialised nfs_fattr structure
141  *
142  * This helper maps the cached NFSv4 owner/group strings in fattr into
143  * their numeric uid/gid equivalents, and then frees the cached strings.
144  */
nfs_fattr_map_and_free_names(struct nfs_server * server,struct nfs_fattr * fattr)145 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
146 {
147 	if (nfs_fattr_map_owner_name(server, fattr))
148 		nfs_fattr_free_owner_name(fattr);
149 	if (nfs_fattr_map_group_name(server, fattr))
150 		nfs_fattr_free_group_name(fattr);
151 }
152 
nfs_map_string_to_numeric(const char * name,size_t namelen,__u32 * res)153 static int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
154 {
155 	unsigned long val;
156 	char buf[16];
157 
158 	if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
159 		return 0;
160 	memcpy(buf, name, namelen);
161 	buf[namelen] = '\0';
162 	if (kstrtoul(buf, 0, &val) != 0)
163 		return 0;
164 	*res = val;
165 	return 1;
166 }
167 
nfs_map_numeric_to_string(__u32 id,char * buf,size_t buflen)168 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
169 {
170 	return snprintf(buf, buflen, "%u", id);
171 }
172 
173 static struct key_type key_type_id_resolver = {
174 	.name		= "id_resolver",
175 	.instantiate	= user_instantiate,
176 	.match		= user_match,
177 	.revoke		= user_revoke,
178 	.destroy	= user_destroy,
179 	.describe	= user_describe,
180 	.read		= user_read,
181 };
182 
nfs_idmap_init_keyring(void)183 static int nfs_idmap_init_keyring(void)
184 {
185 	struct cred *cred;
186 	struct key *keyring;
187 	int ret = 0;
188 
189 	printk(KERN_NOTICE "NFS: Registering the %s key type\n",
190 		key_type_id_resolver.name);
191 
192 	cred = prepare_kernel_cred(NULL);
193 	if (!cred)
194 		return -ENOMEM;
195 
196 	keyring = keyring_alloc(".id_resolver",
197 				GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
198 				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
199 				KEY_USR_VIEW | KEY_USR_READ,
200 				KEY_ALLOC_NOT_IN_QUOTA, NULL);
201 	if (IS_ERR(keyring)) {
202 		ret = PTR_ERR(keyring);
203 		goto failed_put_cred;
204 	}
205 
206 	ret = register_key_type(&key_type_id_resolver);
207 	if (ret < 0)
208 		goto failed_put_key;
209 
210 	ret = register_key_type(&key_type_id_resolver_legacy);
211 	if (ret < 0)
212 		goto failed_reg_legacy;
213 
214 	set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
215 	cred->thread_keyring = keyring;
216 	cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
217 	id_resolver_cache = cred;
218 	return 0;
219 
220 failed_reg_legacy:
221 	unregister_key_type(&key_type_id_resolver);
222 failed_put_key:
223 	key_put(keyring);
224 failed_put_cred:
225 	put_cred(cred);
226 	return ret;
227 }
228 
nfs_idmap_quit_keyring(void)229 static void nfs_idmap_quit_keyring(void)
230 {
231 	key_revoke(id_resolver_cache->thread_keyring);
232 	unregister_key_type(&key_type_id_resolver);
233 	unregister_key_type(&key_type_id_resolver_legacy);
234 	put_cred(id_resolver_cache);
235 }
236 
237 /*
238  * Assemble the description to pass to request_key()
239  * This function will allocate a new string and update dest to point
240  * at it.  The caller is responsible for freeing dest.
241  *
242  * On error 0 is returned.  Otherwise, the length of dest is returned.
243  */
nfs_idmap_get_desc(const char * name,size_t namelen,const char * type,size_t typelen,char ** desc)244 static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
245 				const char *type, size_t typelen, char **desc)
246 {
247 	char *cp;
248 	size_t desclen = typelen + namelen + 2;
249 
250 	*desc = kmalloc(desclen, GFP_KERNEL);
251 	if (!*desc)
252 		return -ENOMEM;
253 
254 	cp = *desc;
255 	memcpy(cp, type, typelen);
256 	cp += typelen;
257 	*cp++ = ':';
258 
259 	memcpy(cp, name, namelen);
260 	cp += namelen;
261 	*cp = '\0';
262 	return desclen;
263 }
264 
nfs_idmap_request_key(struct key_type * key_type,const char * name,size_t namelen,const char * type,void * data,size_t data_size,struct idmap * idmap)265 static ssize_t nfs_idmap_request_key(struct key_type *key_type,
266 				     const char *name, size_t namelen,
267 				     const char *type, void *data,
268 				     size_t data_size, struct idmap *idmap)
269 {
270 	const struct cred *saved_cred;
271 	struct key *rkey;
272 	char *desc;
273 	struct user_key_payload *payload;
274 	ssize_t ret;
275 
276 	ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
277 	if (ret <= 0)
278 		goto out;
279 
280 	saved_cred = override_creds(id_resolver_cache);
281 	if (idmap)
282 		rkey = request_key_with_auxdata(key_type, desc, "", 0, idmap);
283 	else
284 		rkey = request_key(&key_type_id_resolver, desc, "");
285 	revert_creds(saved_cred);
286 
287 	kfree(desc);
288 	if (IS_ERR(rkey)) {
289 		ret = PTR_ERR(rkey);
290 		goto out;
291 	}
292 
293 	rcu_read_lock();
294 	rkey->perm |= KEY_USR_VIEW;
295 
296 	ret = key_validate(rkey);
297 	if (ret < 0)
298 		goto out_up;
299 
300 	payload = rcu_dereference(rkey->payload.data);
301 	if (IS_ERR_OR_NULL(payload)) {
302 		ret = PTR_ERR(payload);
303 		goto out_up;
304 	}
305 
306 	ret = payload->datalen;
307 	if (ret > 0 && ret <= data_size)
308 		memcpy(data, payload->data, ret);
309 	else
310 		ret = -EINVAL;
311 
312 out_up:
313 	rcu_read_unlock();
314 	key_put(rkey);
315 out:
316 	return ret;
317 }
318 
nfs_idmap_get_key(const char * name,size_t namelen,const char * type,void * data,size_t data_size,struct idmap * idmap)319 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
320 				 const char *type, void *data,
321 				 size_t data_size, struct idmap *idmap)
322 {
323 	ssize_t ret = nfs_idmap_request_key(&key_type_id_resolver,
324 					    name, namelen, type, data,
325 					    data_size, NULL);
326 	if (ret < 0) {
327 		mutex_lock(&idmap->idmap_mutex);
328 		ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
329 					    name, namelen, type, data,
330 					    data_size, idmap);
331 		mutex_unlock(&idmap->idmap_mutex);
332 	}
333 	return ret;
334 }
335 
336 /* ID -> Name */
nfs_idmap_lookup_name(__u32 id,const char * type,char * buf,size_t buflen,struct idmap * idmap)337 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
338 				     size_t buflen, struct idmap *idmap)
339 {
340 	char id_str[NFS_UINT_MAXLEN];
341 	int id_len;
342 	ssize_t ret;
343 
344 	id_len = snprintf(id_str, sizeof(id_str), "%u", id);
345 	ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
346 	if (ret < 0)
347 		return -EINVAL;
348 	return ret;
349 }
350 
351 /* Name -> ID */
nfs_idmap_lookup_id(const char * name,size_t namelen,const char * type,__u32 * id,struct idmap * idmap)352 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
353 			       __u32 *id, struct idmap *idmap)
354 {
355 	char id_str[NFS_UINT_MAXLEN];
356 	long id_long;
357 	ssize_t data_size;
358 	int ret = 0;
359 
360 	data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
361 	if (data_size <= 0) {
362 		ret = -EINVAL;
363 	} else {
364 		ret = kstrtol(id_str, 10, &id_long);
365 		*id = (__u32)id_long;
366 	}
367 	return ret;
368 }
369 
370 /* idmap classic begins here */
371 
372 enum {
373 	Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
374 };
375 
376 static const match_table_t nfs_idmap_tokens = {
377 	{ Opt_find_uid, "uid:%s" },
378 	{ Opt_find_gid, "gid:%s" },
379 	{ Opt_find_user, "user:%s" },
380 	{ Opt_find_group, "group:%s" },
381 	{ Opt_find_err, NULL }
382 };
383 
384 static int nfs_idmap_legacy_upcall(struct key_construction *, const char *, void *);
385 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
386 				   size_t);
387 static void idmap_release_pipe(struct inode *);
388 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
389 
390 static const struct rpc_pipe_ops idmap_upcall_ops = {
391 	.upcall		= rpc_pipe_generic_upcall,
392 	.downcall	= idmap_pipe_downcall,
393 	.release_pipe	= idmap_release_pipe,
394 	.destroy_msg	= idmap_pipe_destroy_msg,
395 };
396 
397 static struct key_type key_type_id_resolver_legacy = {
398 	.name		= "id_legacy",
399 	.instantiate	= user_instantiate,
400 	.match		= user_match,
401 	.revoke		= user_revoke,
402 	.destroy	= user_destroy,
403 	.describe	= user_describe,
404 	.read		= user_read,
405 	.request_key	= nfs_idmap_legacy_upcall,
406 };
407 
__nfs_idmap_unregister(struct rpc_pipe * pipe)408 static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
409 {
410 	if (pipe->dentry)
411 		rpc_unlink(pipe->dentry);
412 }
413 
__nfs_idmap_register(struct dentry * dir,struct idmap * idmap,struct rpc_pipe * pipe)414 static int __nfs_idmap_register(struct dentry *dir,
415 				     struct idmap *idmap,
416 				     struct rpc_pipe *pipe)
417 {
418 	struct dentry *dentry;
419 
420 	dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
421 	if (IS_ERR(dentry))
422 		return PTR_ERR(dentry);
423 	pipe->dentry = dentry;
424 	return 0;
425 }
426 
nfs_idmap_unregister(struct nfs_client * clp,struct rpc_pipe * pipe)427 static void nfs_idmap_unregister(struct nfs_client *clp,
428 				      struct rpc_pipe *pipe)
429 {
430 	struct net *net = clp->cl_net;
431 	struct super_block *pipefs_sb;
432 
433 	pipefs_sb = rpc_get_sb_net(net);
434 	if (pipefs_sb) {
435 		__nfs_idmap_unregister(pipe);
436 		rpc_put_sb_net(net);
437 	}
438 }
439 
nfs_idmap_register(struct nfs_client * clp,struct idmap * idmap,struct rpc_pipe * pipe)440 static int nfs_idmap_register(struct nfs_client *clp,
441 				   struct idmap *idmap,
442 				   struct rpc_pipe *pipe)
443 {
444 	struct net *net = clp->cl_net;
445 	struct super_block *pipefs_sb;
446 	int err = 0;
447 
448 	pipefs_sb = rpc_get_sb_net(net);
449 	if (pipefs_sb) {
450 		if (clp->cl_rpcclient->cl_dentry)
451 			err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
452 						   idmap, pipe);
453 		rpc_put_sb_net(net);
454 	}
455 	return err;
456 }
457 
458 int
nfs_idmap_new(struct nfs_client * clp)459 nfs_idmap_new(struct nfs_client *clp)
460 {
461 	struct idmap *idmap;
462 	struct rpc_pipe *pipe;
463 	int error;
464 
465 	idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
466 	if (idmap == NULL)
467 		return -ENOMEM;
468 
469 	pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
470 	if (IS_ERR(pipe)) {
471 		error = PTR_ERR(pipe);
472 		kfree(idmap);
473 		return error;
474 	}
475 	error = nfs_idmap_register(clp, idmap, pipe);
476 	if (error) {
477 		rpc_destroy_pipe_data(pipe);
478 		kfree(idmap);
479 		return error;
480 	}
481 	idmap->idmap_pipe = pipe;
482 	mutex_init(&idmap->idmap_mutex);
483 
484 	clp->cl_idmap = idmap;
485 	return 0;
486 }
487 
488 void
nfs_idmap_delete(struct nfs_client * clp)489 nfs_idmap_delete(struct nfs_client *clp)
490 {
491 	struct idmap *idmap = clp->cl_idmap;
492 
493 	if (!idmap)
494 		return;
495 	nfs_idmap_unregister(clp, idmap->idmap_pipe);
496 	rpc_destroy_pipe_data(idmap->idmap_pipe);
497 	clp->cl_idmap = NULL;
498 	kfree(idmap);
499 }
500 
__rpc_pipefs_event(struct nfs_client * clp,unsigned long event,struct super_block * sb)501 static int __rpc_pipefs_event(struct nfs_client *clp, unsigned long event,
502 			      struct super_block *sb)
503 {
504 	int err = 0;
505 
506 	switch (event) {
507 	case RPC_PIPEFS_MOUNT:
508 		err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
509 						clp->cl_idmap,
510 						clp->cl_idmap->idmap_pipe);
511 		break;
512 	case RPC_PIPEFS_UMOUNT:
513 		if (clp->cl_idmap->idmap_pipe) {
514 			struct dentry *parent;
515 
516 			parent = clp->cl_idmap->idmap_pipe->dentry->d_parent;
517 			__nfs_idmap_unregister(clp->cl_idmap->idmap_pipe);
518 			/*
519 			 * Note: This is a dirty hack. SUNRPC hook has been
520 			 * called already but simple_rmdir() call for the
521 			 * directory returned with error because of idmap pipe
522 			 * inside. Thus now we have to remove this directory
523 			 * here.
524 			 */
525 			if (rpc_rmdir(parent))
526 				printk(KERN_ERR "NFS: %s: failed to remove "
527 					"clnt dir!\n", __func__);
528 		}
529 		break;
530 	default:
531 		printk(KERN_ERR "NFS: %s: unknown event: %ld\n", __func__,
532 			event);
533 		return -ENOTSUPP;
534 	}
535 	return err;
536 }
537 
nfs_get_client_for_event(struct net * net,int event)538 static struct nfs_client *nfs_get_client_for_event(struct net *net, int event)
539 {
540 	struct nfs_net *nn = net_generic(net, nfs_net_id);
541 	struct dentry *cl_dentry;
542 	struct nfs_client *clp;
543 	int err;
544 
545 restart:
546 	spin_lock(&nn->nfs_client_lock);
547 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
548 		/* Wait for initialisation to finish */
549 		if (clp->cl_cons_state == NFS_CS_INITING) {
550 			atomic_inc(&clp->cl_count);
551 			spin_unlock(&nn->nfs_client_lock);
552 			err = nfs_wait_client_init_complete(clp);
553 			nfs_put_client(clp);
554 			if (err)
555 				return NULL;
556 			goto restart;
557 		}
558 		/* Skip nfs_clients that failed to initialise */
559 		if (clp->cl_cons_state < 0)
560 			continue;
561 		smp_rmb();
562 		if (clp->rpc_ops != &nfs_v4_clientops)
563 			continue;
564 		cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
565 		if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) ||
566 		    ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
567 			continue;
568 		atomic_inc(&clp->cl_count);
569 		spin_unlock(&nn->nfs_client_lock);
570 		return clp;
571 	}
572 	spin_unlock(&nn->nfs_client_lock);
573 	return NULL;
574 }
575 
rpc_pipefs_event(struct notifier_block * nb,unsigned long event,void * ptr)576 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
577 			    void *ptr)
578 {
579 	struct super_block *sb = ptr;
580 	struct nfs_client *clp;
581 	int error = 0;
582 
583 	if (!try_module_get(THIS_MODULE))
584 		return 0;
585 
586 	while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
587 		error = __rpc_pipefs_event(clp, event, sb);
588 		nfs_put_client(clp);
589 		if (error)
590 			break;
591 	}
592 	module_put(THIS_MODULE);
593 	return error;
594 }
595 
596 #define PIPEFS_NFS_PRIO		1
597 
598 static struct notifier_block nfs_idmap_block = {
599 	.notifier_call	= rpc_pipefs_event,
600 	.priority	= SUNRPC_PIPEFS_NFS_PRIO,
601 };
602 
nfs_idmap_init(void)603 int nfs_idmap_init(void)
604 {
605 	int ret;
606 	ret = nfs_idmap_init_keyring();
607 	if (ret != 0)
608 		goto out;
609 	ret = rpc_pipefs_notifier_register(&nfs_idmap_block);
610 	if (ret != 0)
611 		nfs_idmap_quit_keyring();
612 out:
613 	return ret;
614 }
615 
nfs_idmap_quit(void)616 void nfs_idmap_quit(void)
617 {
618 	rpc_pipefs_notifier_unregister(&nfs_idmap_block);
619 	nfs_idmap_quit_keyring();
620 }
621 
nfs_idmap_prepare_message(char * desc,struct idmap * idmap,struct idmap_msg * im,struct rpc_pipe_msg * msg)622 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
623 				     struct idmap_msg *im,
624 				     struct rpc_pipe_msg *msg)
625 {
626 	substring_t substr;
627 	int token, ret;
628 
629 	im->im_type = IDMAP_TYPE_GROUP;
630 	token = match_token(desc, nfs_idmap_tokens, &substr);
631 
632 	switch (token) {
633 	case Opt_find_uid:
634 		im->im_type = IDMAP_TYPE_USER;
635 	case Opt_find_gid:
636 		im->im_conv = IDMAP_CONV_NAMETOID;
637 		ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
638 		break;
639 
640 	case Opt_find_user:
641 		im->im_type = IDMAP_TYPE_USER;
642 	case Opt_find_group:
643 		im->im_conv = IDMAP_CONV_IDTONAME;
644 		ret = match_int(&substr, &im->im_id);
645 		break;
646 
647 	default:
648 		ret = -EINVAL;
649 		goto out;
650 	}
651 
652 	msg->data = im;
653 	msg->len  = sizeof(struct idmap_msg);
654 
655 out:
656 	return ret;
657 }
658 
659 static bool
nfs_idmap_prepare_pipe_upcall(struct idmap * idmap,struct idmap_legacy_upcalldata * data)660 nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
661 		struct idmap_legacy_upcalldata *data)
662 {
663 	if (idmap->idmap_upcall_data != NULL) {
664 		WARN_ON_ONCE(1);
665 		return false;
666 	}
667 	idmap->idmap_upcall_data = data;
668 	return true;
669 }
670 
671 static void
nfs_idmap_complete_pipe_upcall_locked(struct idmap * idmap,int ret)672 nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
673 {
674 	struct key_construction *cons = idmap->idmap_upcall_data->key_cons;
675 
676 	kfree(idmap->idmap_upcall_data);
677 	idmap->idmap_upcall_data = NULL;
678 	complete_request_key(cons, ret);
679 }
680 
681 static void
nfs_idmap_abort_pipe_upcall(struct idmap * idmap,int ret)682 nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
683 {
684 	if (idmap->idmap_upcall_data != NULL)
685 		nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
686 }
687 
nfs_idmap_legacy_upcall(struct key_construction * cons,const char * op,void * aux)688 static int nfs_idmap_legacy_upcall(struct key_construction *cons,
689 				   const char *op,
690 				   void *aux)
691 {
692 	struct idmap_legacy_upcalldata *data;
693 	struct rpc_pipe_msg *msg;
694 	struct idmap_msg *im;
695 	struct idmap *idmap = (struct idmap *)aux;
696 	struct key *key = cons->key;
697 	int ret = -ENOMEM;
698 
699 	/* msg and im are freed in idmap_pipe_destroy_msg */
700 	data = kzalloc(sizeof(*data), GFP_KERNEL);
701 	if (!data)
702 		goto out1;
703 
704 	msg = &data->pipe_msg;
705 	im = &data->idmap_msg;
706 	data->idmap = idmap;
707 	data->key_cons = cons;
708 
709 	ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
710 	if (ret < 0)
711 		goto out2;
712 
713 	ret = -EAGAIN;
714 	if (!nfs_idmap_prepare_pipe_upcall(idmap, data))
715 		goto out2;
716 
717 	ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
718 	if (ret < 0)
719 		nfs_idmap_abort_pipe_upcall(idmap, ret);
720 
721 	return ret;
722 out2:
723 	kfree(data);
724 out1:
725 	complete_request_key(cons, ret);
726 	return ret;
727 }
728 
nfs_idmap_instantiate(struct key * key,struct key * authkey,char * data,size_t datalen)729 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
730 {
731 	return key_instantiate_and_link(key, data, datalen,
732 					id_resolver_cache->thread_keyring,
733 					authkey);
734 }
735 
nfs_idmap_read_and_verify_message(struct idmap_msg * im,struct idmap_msg * upcall,struct key * key,struct key * authkey)736 static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
737 		struct idmap_msg *upcall,
738 		struct key *key, struct key *authkey)
739 {
740 	char id_str[NFS_UINT_MAXLEN];
741 	size_t len;
742 	int ret = -ENOKEY;
743 
744 	/* ret = -ENOKEY */
745 	if (upcall->im_type != im->im_type || upcall->im_conv != im->im_conv)
746 		goto out;
747 	switch (im->im_conv) {
748 	case IDMAP_CONV_NAMETOID:
749 		if (strcmp(upcall->im_name, im->im_name) != 0)
750 			break;
751 		/* Note: here we store the NUL terminator too */
752 		len = sprintf(id_str, "%d", im->im_id) + 1;
753 		ret = nfs_idmap_instantiate(key, authkey, id_str, len);
754 		break;
755 	case IDMAP_CONV_IDTONAME:
756 		if (upcall->im_id != im->im_id)
757 			break;
758 		len = strlen(im->im_name);
759 		ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
760 		break;
761 	default:
762 		ret = -EINVAL;
763 	}
764 out:
765 	return ret;
766 }
767 
768 static ssize_t
idmap_pipe_downcall(struct file * filp,const char __user * src,size_t mlen)769 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
770 {
771 	struct rpc_inode *rpci = RPC_I(file_inode(filp));
772 	struct idmap *idmap = (struct idmap *)rpci->private;
773 	struct key_construction *cons;
774 	struct idmap_msg im;
775 	size_t namelen_in;
776 	int ret = -ENOKEY;
777 
778 	/* If instantiation is successful, anyone waiting for key construction
779 	 * will have been woken up and someone else may now have used
780 	 * idmap_key_cons - so after this point we may no longer touch it.
781 	 */
782 	if (idmap->idmap_upcall_data == NULL)
783 		goto out_noupcall;
784 
785 	cons = idmap->idmap_upcall_data->key_cons;
786 
787 	if (mlen != sizeof(im)) {
788 		ret = -ENOSPC;
789 		goto out;
790 	}
791 
792 	if (copy_from_user(&im, src, mlen) != 0) {
793 		ret = -EFAULT;
794 		goto out;
795 	}
796 
797 	if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
798 		ret = -ENOKEY;
799 		goto out;
800 	}
801 
802 	namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
803 	if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
804 		ret = -EINVAL;
805 		goto out;
806 }
807 
808 	ret = nfs_idmap_read_and_verify_message(&im,
809 			&idmap->idmap_upcall_data->idmap_msg,
810 			cons->key, cons->authkey);
811 	if (ret >= 0) {
812 		key_set_timeout(cons->key, nfs_idmap_cache_timeout);
813 		ret = mlen;
814 	}
815 
816 out:
817 	nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
818 out_noupcall:
819 	return ret;
820 }
821 
822 static void
idmap_pipe_destroy_msg(struct rpc_pipe_msg * msg)823 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
824 {
825 	struct idmap_legacy_upcalldata *data = container_of(msg,
826 			struct idmap_legacy_upcalldata,
827 			pipe_msg);
828 	struct idmap *idmap = data->idmap;
829 
830 	if (msg->errno)
831 		nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
832 }
833 
834 static void
idmap_release_pipe(struct inode * inode)835 idmap_release_pipe(struct inode *inode)
836 {
837 	struct rpc_inode *rpci = RPC_I(inode);
838 	struct idmap *idmap = (struct idmap *)rpci->private;
839 
840 	nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
841 }
842 
nfs_map_name_to_uid(const struct nfs_server * server,const char * name,size_t namelen,kuid_t * uid)843 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)
844 {
845 	struct idmap *idmap = server->nfs_client->cl_idmap;
846 	__u32 id = -1;
847 	int ret = 0;
848 
849 	if (!nfs_map_string_to_numeric(name, namelen, &id))
850 		ret = nfs_idmap_lookup_id(name, namelen, "uid", &id, idmap);
851 	if (ret == 0) {
852 		*uid = make_kuid(&init_user_ns, id);
853 		if (!uid_valid(*uid))
854 			ret = -ERANGE;
855 	}
856 	return ret;
857 }
858 
nfs_map_group_to_gid(const struct nfs_server * server,const char * name,size_t namelen,kgid_t * gid)859 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, kgid_t *gid)
860 {
861 	struct idmap *idmap = server->nfs_client->cl_idmap;
862 	__u32 id = -1;
863 	int ret = 0;
864 
865 	if (!nfs_map_string_to_numeric(name, namelen, &id))
866 		ret = nfs_idmap_lookup_id(name, namelen, "gid", &id, idmap);
867 	if (ret == 0) {
868 		*gid = make_kgid(&init_user_ns, id);
869 		if (!gid_valid(*gid))
870 			ret = -ERANGE;
871 	}
872 	return ret;
873 }
874 
nfs_map_uid_to_name(const struct nfs_server * server,kuid_t uid,char * buf,size_t buflen)875 int nfs_map_uid_to_name(const struct nfs_server *server, kuid_t uid, char *buf, size_t buflen)
876 {
877 	struct idmap *idmap = server->nfs_client->cl_idmap;
878 	int ret = -EINVAL;
879 	__u32 id;
880 
881 	id = from_kuid(&init_user_ns, uid);
882 	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
883 		ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
884 	if (ret < 0)
885 		ret = nfs_map_numeric_to_string(id, buf, buflen);
886 	return ret;
887 }
nfs_map_gid_to_group(const struct nfs_server * server,kgid_t gid,char * buf,size_t buflen)888 int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
889 {
890 	struct idmap *idmap = server->nfs_client->cl_idmap;
891 	int ret = -EINVAL;
892 	__u32 id;
893 
894 	id = from_kgid(&init_user_ns, gid);
895 	if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
896 		ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
897 	if (ret < 0)
898 		ret = nfs_map_numeric_to_string(id, buf, buflen);
899 	return ret;
900 }
901