xref: /openbmc/linux/net/sunrpc/auth.c (revision 2572f00d)
1 /*
2  * linux/net/sunrpc/auth.c
3  *
4  * Generic RPC client authentication API.
5  *
6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7  */
8 
9 #include <linux/types.h>
10 #include <linux/sched.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/errno.h>
14 #include <linux/hash.h>
15 #include <linux/sunrpc/clnt.h>
16 #include <linux/sunrpc/gss_api.h>
17 #include <linux/spinlock.h>
18 
19 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
20 # define RPCDBG_FACILITY	RPCDBG_AUTH
21 #endif
22 
23 #define RPC_CREDCACHE_DEFAULT_HASHBITS	(4)
24 struct rpc_cred_cache {
25 	struct hlist_head	*hashtable;
26 	unsigned int		hashbits;
27 	spinlock_t		lock;
28 };
29 
30 static unsigned int auth_hashbits = RPC_CREDCACHE_DEFAULT_HASHBITS;
31 
32 static DEFINE_SPINLOCK(rpc_authflavor_lock);
33 static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
34 	&authnull_ops,		/* AUTH_NULL */
35 	&authunix_ops,		/* AUTH_UNIX */
36 	NULL,			/* others can be loadable modules */
37 };
38 
39 static LIST_HEAD(cred_unused);
40 static unsigned long number_cred_unused;
41 
42 #define MAX_HASHTABLE_BITS (14)
43 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
44 {
45 	unsigned long num;
46 	unsigned int nbits;
47 	int ret;
48 
49 	if (!val)
50 		goto out_inval;
51 	ret = kstrtoul(val, 0, &num);
52 	if (ret == -EINVAL)
53 		goto out_inval;
54 	nbits = fls(num);
55 	if (num > (1U << nbits))
56 		nbits++;
57 	if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
58 		goto out_inval;
59 	*(unsigned int *)kp->arg = nbits;
60 	return 0;
61 out_inval:
62 	return -EINVAL;
63 }
64 
65 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
66 {
67 	unsigned int nbits;
68 
69 	nbits = *(unsigned int *)kp->arg;
70 	return sprintf(buffer, "%u", 1U << nbits);
71 }
72 
73 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
74 
75 static const struct kernel_param_ops param_ops_hashtbl_sz = {
76 	.set = param_set_hashtbl_sz,
77 	.get = param_get_hashtbl_sz,
78 };
79 
80 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
81 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
82 
83 static unsigned long auth_max_cred_cachesize = ULONG_MAX;
84 module_param(auth_max_cred_cachesize, ulong, 0644);
85 MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size");
86 
87 static u32
88 pseudoflavor_to_flavor(u32 flavor) {
89 	if (flavor > RPC_AUTH_MAXFLAVOR)
90 		return RPC_AUTH_GSS;
91 	return flavor;
92 }
93 
94 int
95 rpcauth_register(const struct rpc_authops *ops)
96 {
97 	rpc_authflavor_t flavor;
98 	int ret = -EPERM;
99 
100 	if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
101 		return -EINVAL;
102 	spin_lock(&rpc_authflavor_lock);
103 	if (auth_flavors[flavor] == NULL) {
104 		auth_flavors[flavor] = ops;
105 		ret = 0;
106 	}
107 	spin_unlock(&rpc_authflavor_lock);
108 	return ret;
109 }
110 EXPORT_SYMBOL_GPL(rpcauth_register);
111 
112 int
113 rpcauth_unregister(const struct rpc_authops *ops)
114 {
115 	rpc_authflavor_t flavor;
116 	int ret = -EPERM;
117 
118 	if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
119 		return -EINVAL;
120 	spin_lock(&rpc_authflavor_lock);
121 	if (auth_flavors[flavor] == ops) {
122 		auth_flavors[flavor] = NULL;
123 		ret = 0;
124 	}
125 	spin_unlock(&rpc_authflavor_lock);
126 	return ret;
127 }
128 EXPORT_SYMBOL_GPL(rpcauth_unregister);
129 
130 /**
131  * rpcauth_get_pseudoflavor - check if security flavor is supported
132  * @flavor: a security flavor
133  * @info: a GSS mech OID, quality of protection, and service value
134  *
135  * Verifies that an appropriate kernel module is available or already loaded.
136  * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
137  * not supported locally.
138  */
139 rpc_authflavor_t
140 rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
141 {
142 	const struct rpc_authops *ops;
143 	rpc_authflavor_t pseudoflavor;
144 
145 	ops = auth_flavors[flavor];
146 	if (ops == NULL)
147 		request_module("rpc-auth-%u", flavor);
148 	spin_lock(&rpc_authflavor_lock);
149 	ops = auth_flavors[flavor];
150 	if (ops == NULL || !try_module_get(ops->owner)) {
151 		spin_unlock(&rpc_authflavor_lock);
152 		return RPC_AUTH_MAXFLAVOR;
153 	}
154 	spin_unlock(&rpc_authflavor_lock);
155 
156 	pseudoflavor = flavor;
157 	if (ops->info2flavor != NULL)
158 		pseudoflavor = ops->info2flavor(info);
159 
160 	module_put(ops->owner);
161 	return pseudoflavor;
162 }
163 EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
164 
165 /**
166  * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor
167  * @pseudoflavor: GSS pseudoflavor to match
168  * @info: rpcsec_gss_info structure to fill in
169  *
170  * Returns zero and fills in "info" if pseudoflavor matches a
171  * supported mechanism.
172  */
173 int
174 rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
175 {
176 	rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor);
177 	const struct rpc_authops *ops;
178 	int result;
179 
180 	if (flavor >= RPC_AUTH_MAXFLAVOR)
181 		return -EINVAL;
182 
183 	ops = auth_flavors[flavor];
184 	if (ops == NULL)
185 		request_module("rpc-auth-%u", flavor);
186 	spin_lock(&rpc_authflavor_lock);
187 	ops = auth_flavors[flavor];
188 	if (ops == NULL || !try_module_get(ops->owner)) {
189 		spin_unlock(&rpc_authflavor_lock);
190 		return -ENOENT;
191 	}
192 	spin_unlock(&rpc_authflavor_lock);
193 
194 	result = -ENOENT;
195 	if (ops->flavor2info != NULL)
196 		result = ops->flavor2info(pseudoflavor, info);
197 
198 	module_put(ops->owner);
199 	return result;
200 }
201 EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
202 
203 /**
204  * rpcauth_list_flavors - discover registered flavors and pseudoflavors
205  * @array: array to fill in
206  * @size: size of "array"
207  *
208  * Returns the number of array items filled in, or a negative errno.
209  *
210  * The returned array is not sorted by any policy.  Callers should not
211  * rely on the order of the items in the returned array.
212  */
213 int
214 rpcauth_list_flavors(rpc_authflavor_t *array, int size)
215 {
216 	rpc_authflavor_t flavor;
217 	int result = 0;
218 
219 	spin_lock(&rpc_authflavor_lock);
220 	for (flavor = 0; flavor < RPC_AUTH_MAXFLAVOR; flavor++) {
221 		const struct rpc_authops *ops = auth_flavors[flavor];
222 		rpc_authflavor_t pseudos[4];
223 		int i, len;
224 
225 		if (result >= size) {
226 			result = -ENOMEM;
227 			break;
228 		}
229 
230 		if (ops == NULL)
231 			continue;
232 		if (ops->list_pseudoflavors == NULL) {
233 			array[result++] = ops->au_flavor;
234 			continue;
235 		}
236 		len = ops->list_pseudoflavors(pseudos, ARRAY_SIZE(pseudos));
237 		if (len < 0) {
238 			result = len;
239 			break;
240 		}
241 		for (i = 0; i < len; i++) {
242 			if (result >= size) {
243 				result = -ENOMEM;
244 				break;
245 			}
246 			array[result++] = pseudos[i];
247 		}
248 	}
249 	spin_unlock(&rpc_authflavor_lock);
250 
251 	dprintk("RPC:       %s returns %d\n", __func__, result);
252 	return result;
253 }
254 EXPORT_SYMBOL_GPL(rpcauth_list_flavors);
255 
256 struct rpc_auth *
257 rpcauth_create(struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
258 {
259 	struct rpc_auth		*auth;
260 	const struct rpc_authops *ops;
261 	u32			flavor = pseudoflavor_to_flavor(args->pseudoflavor);
262 
263 	auth = ERR_PTR(-EINVAL);
264 	if (flavor >= RPC_AUTH_MAXFLAVOR)
265 		goto out;
266 
267 	if ((ops = auth_flavors[flavor]) == NULL)
268 		request_module("rpc-auth-%u", flavor);
269 	spin_lock(&rpc_authflavor_lock);
270 	ops = auth_flavors[flavor];
271 	if (ops == NULL || !try_module_get(ops->owner)) {
272 		spin_unlock(&rpc_authflavor_lock);
273 		goto out;
274 	}
275 	spin_unlock(&rpc_authflavor_lock);
276 	auth = ops->create(args, clnt);
277 	module_put(ops->owner);
278 	if (IS_ERR(auth))
279 		return auth;
280 	if (clnt->cl_auth)
281 		rpcauth_release(clnt->cl_auth);
282 	clnt->cl_auth = auth;
283 
284 out:
285 	return auth;
286 }
287 EXPORT_SYMBOL_GPL(rpcauth_create);
288 
289 void
290 rpcauth_release(struct rpc_auth *auth)
291 {
292 	if (!atomic_dec_and_test(&auth->au_count))
293 		return;
294 	auth->au_ops->destroy(auth);
295 }
296 
297 static DEFINE_SPINLOCK(rpc_credcache_lock);
298 
299 static void
300 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
301 {
302 	hlist_del_rcu(&cred->cr_hash);
303 	smp_mb__before_atomic();
304 	clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
305 }
306 
307 static int
308 rpcauth_unhash_cred(struct rpc_cred *cred)
309 {
310 	spinlock_t *cache_lock;
311 	int ret;
312 
313 	cache_lock = &cred->cr_auth->au_credcache->lock;
314 	spin_lock(cache_lock);
315 	ret = atomic_read(&cred->cr_count) == 0;
316 	if (ret)
317 		rpcauth_unhash_cred_locked(cred);
318 	spin_unlock(cache_lock);
319 	return ret;
320 }
321 
322 /*
323  * Initialize RPC credential cache
324  */
325 int
326 rpcauth_init_credcache(struct rpc_auth *auth)
327 {
328 	struct rpc_cred_cache *new;
329 	unsigned int hashsize;
330 
331 	new = kmalloc(sizeof(*new), GFP_KERNEL);
332 	if (!new)
333 		goto out_nocache;
334 	new->hashbits = auth_hashbits;
335 	hashsize = 1U << new->hashbits;
336 	new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
337 	if (!new->hashtable)
338 		goto out_nohashtbl;
339 	spin_lock_init(&new->lock);
340 	auth->au_credcache = new;
341 	return 0;
342 out_nohashtbl:
343 	kfree(new);
344 out_nocache:
345 	return -ENOMEM;
346 }
347 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
348 
349 /*
350  * Setup a credential key lifetime timeout notification
351  */
352 int
353 rpcauth_key_timeout_notify(struct rpc_auth *auth, struct rpc_cred *cred)
354 {
355 	if (!cred->cr_auth->au_ops->key_timeout)
356 		return 0;
357 	return cred->cr_auth->au_ops->key_timeout(auth, cred);
358 }
359 EXPORT_SYMBOL_GPL(rpcauth_key_timeout_notify);
360 
361 bool
362 rpcauth_cred_key_to_expire(struct rpc_cred *cred)
363 {
364 	if (!cred->cr_ops->crkey_to_expire)
365 		return false;
366 	return cred->cr_ops->crkey_to_expire(cred);
367 }
368 EXPORT_SYMBOL_GPL(rpcauth_cred_key_to_expire);
369 
370 char *
371 rpcauth_stringify_acceptor(struct rpc_cred *cred)
372 {
373 	if (!cred->cr_ops->crstringify_acceptor)
374 		return NULL;
375 	return cred->cr_ops->crstringify_acceptor(cred);
376 }
377 EXPORT_SYMBOL_GPL(rpcauth_stringify_acceptor);
378 
379 /*
380  * Destroy a list of credentials
381  */
382 static inline
383 void rpcauth_destroy_credlist(struct list_head *head)
384 {
385 	struct rpc_cred *cred;
386 
387 	while (!list_empty(head)) {
388 		cred = list_entry(head->next, struct rpc_cred, cr_lru);
389 		list_del_init(&cred->cr_lru);
390 		put_rpccred(cred);
391 	}
392 }
393 
394 /*
395  * Clear the RPC credential cache, and delete those credentials
396  * that are not referenced.
397  */
398 void
399 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
400 {
401 	LIST_HEAD(free);
402 	struct hlist_head *head;
403 	struct rpc_cred	*cred;
404 	unsigned int hashsize = 1U << cache->hashbits;
405 	int		i;
406 
407 	spin_lock(&rpc_credcache_lock);
408 	spin_lock(&cache->lock);
409 	for (i = 0; i < hashsize; i++) {
410 		head = &cache->hashtable[i];
411 		while (!hlist_empty(head)) {
412 			cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
413 			get_rpccred(cred);
414 			if (!list_empty(&cred->cr_lru)) {
415 				list_del(&cred->cr_lru);
416 				number_cred_unused--;
417 			}
418 			list_add_tail(&cred->cr_lru, &free);
419 			rpcauth_unhash_cred_locked(cred);
420 		}
421 	}
422 	spin_unlock(&cache->lock);
423 	spin_unlock(&rpc_credcache_lock);
424 	rpcauth_destroy_credlist(&free);
425 }
426 
427 /*
428  * Destroy the RPC credential cache
429  */
430 void
431 rpcauth_destroy_credcache(struct rpc_auth *auth)
432 {
433 	struct rpc_cred_cache *cache = auth->au_credcache;
434 
435 	if (cache) {
436 		auth->au_credcache = NULL;
437 		rpcauth_clear_credcache(cache);
438 		kfree(cache->hashtable);
439 		kfree(cache);
440 	}
441 }
442 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
443 
444 
445 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
446 
447 /*
448  * Remove stale credentials. Avoid sleeping inside the loop.
449  */
450 static long
451 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
452 {
453 	spinlock_t *cache_lock;
454 	struct rpc_cred *cred, *next;
455 	unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
456 	long freed = 0;
457 
458 	list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
459 
460 		if (nr_to_scan-- == 0)
461 			break;
462 		/*
463 		 * Enforce a 60 second garbage collection moratorium
464 		 * Note that the cred_unused list must be time-ordered.
465 		 */
466 		if (time_in_range(cred->cr_expire, expired, jiffies) &&
467 		    test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
468 			break;
469 
470 		list_del_init(&cred->cr_lru);
471 		number_cred_unused--;
472 		freed++;
473 		if (atomic_read(&cred->cr_count) != 0)
474 			continue;
475 
476 		cache_lock = &cred->cr_auth->au_credcache->lock;
477 		spin_lock(cache_lock);
478 		if (atomic_read(&cred->cr_count) == 0) {
479 			get_rpccred(cred);
480 			list_add_tail(&cred->cr_lru, free);
481 			rpcauth_unhash_cred_locked(cred);
482 		}
483 		spin_unlock(cache_lock);
484 	}
485 	return freed;
486 }
487 
488 static unsigned long
489 rpcauth_cache_do_shrink(int nr_to_scan)
490 {
491 	LIST_HEAD(free);
492 	unsigned long freed;
493 
494 	spin_lock(&rpc_credcache_lock);
495 	freed = rpcauth_prune_expired(&free, nr_to_scan);
496 	spin_unlock(&rpc_credcache_lock);
497 	rpcauth_destroy_credlist(&free);
498 
499 	return freed;
500 }
501 
502 /*
503  * Run memory cache shrinker.
504  */
505 static unsigned long
506 rpcauth_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
507 
508 {
509 	if ((sc->gfp_mask & GFP_KERNEL) != GFP_KERNEL)
510 		return SHRINK_STOP;
511 
512 	/* nothing left, don't come back */
513 	if (list_empty(&cred_unused))
514 		return SHRINK_STOP;
515 
516 	return rpcauth_cache_do_shrink(sc->nr_to_scan);
517 }
518 
519 static unsigned long
520 rpcauth_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
521 
522 {
523 	return (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
524 }
525 
526 static void
527 rpcauth_cache_enforce_limit(void)
528 {
529 	unsigned long diff;
530 	unsigned int nr_to_scan;
531 
532 	if (number_cred_unused <= auth_max_cred_cachesize)
533 		return;
534 	diff = number_cred_unused - auth_max_cred_cachesize;
535 	nr_to_scan = 100;
536 	if (diff < nr_to_scan)
537 		nr_to_scan = diff;
538 	rpcauth_cache_do_shrink(nr_to_scan);
539 }
540 
541 /*
542  * Look up a process' credentials in the authentication cache
543  */
544 struct rpc_cred *
545 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
546 		int flags)
547 {
548 	LIST_HEAD(free);
549 	struct rpc_cred_cache *cache = auth->au_credcache;
550 	struct rpc_cred	*cred = NULL,
551 			*entry, *new;
552 	unsigned int nr;
553 
554 	nr = hash_long(from_kuid(&init_user_ns, acred->uid), cache->hashbits);
555 
556 	rcu_read_lock();
557 	hlist_for_each_entry_rcu(entry, &cache->hashtable[nr], cr_hash) {
558 		if (!entry->cr_ops->crmatch(acred, entry, flags))
559 			continue;
560 		if (flags & RPCAUTH_LOOKUP_RCU) {
561 			if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) &&
562 			    !test_bit(RPCAUTH_CRED_NEW, &entry->cr_flags))
563 				cred = entry;
564 			break;
565 		}
566 		spin_lock(&cache->lock);
567 		if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
568 			spin_unlock(&cache->lock);
569 			continue;
570 		}
571 		cred = get_rpccred(entry);
572 		spin_unlock(&cache->lock);
573 		break;
574 	}
575 	rcu_read_unlock();
576 
577 	if (cred != NULL)
578 		goto found;
579 
580 	if (flags & RPCAUTH_LOOKUP_RCU)
581 		return ERR_PTR(-ECHILD);
582 
583 	new = auth->au_ops->crcreate(auth, acred, flags);
584 	if (IS_ERR(new)) {
585 		cred = new;
586 		goto out;
587 	}
588 
589 	spin_lock(&cache->lock);
590 	hlist_for_each_entry(entry, &cache->hashtable[nr], cr_hash) {
591 		if (!entry->cr_ops->crmatch(acred, entry, flags))
592 			continue;
593 		cred = get_rpccred(entry);
594 		break;
595 	}
596 	if (cred == NULL) {
597 		cred = new;
598 		set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
599 		hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
600 	} else
601 		list_add_tail(&new->cr_lru, &free);
602 	spin_unlock(&cache->lock);
603 	rpcauth_cache_enforce_limit();
604 found:
605 	if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
606 	    cred->cr_ops->cr_init != NULL &&
607 	    !(flags & RPCAUTH_LOOKUP_NEW)) {
608 		int res = cred->cr_ops->cr_init(auth, cred);
609 		if (res < 0) {
610 			put_rpccred(cred);
611 			cred = ERR_PTR(res);
612 		}
613 	}
614 	rpcauth_destroy_credlist(&free);
615 out:
616 	return cred;
617 }
618 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
619 
620 struct rpc_cred *
621 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
622 {
623 	struct auth_cred acred;
624 	struct rpc_cred *ret;
625 	const struct cred *cred = current_cred();
626 
627 	dprintk("RPC:       looking up %s cred\n",
628 		auth->au_ops->au_name);
629 
630 	memset(&acred, 0, sizeof(acred));
631 	acred.uid = cred->fsuid;
632 	acred.gid = cred->fsgid;
633 	acred.group_info = cred->group_info;
634 	ret = auth->au_ops->lookup_cred(auth, &acred, flags);
635 	return ret;
636 }
637 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
638 
639 void
640 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
641 		  struct rpc_auth *auth, const struct rpc_credops *ops)
642 {
643 	INIT_HLIST_NODE(&cred->cr_hash);
644 	INIT_LIST_HEAD(&cred->cr_lru);
645 	atomic_set(&cred->cr_count, 1);
646 	cred->cr_auth = auth;
647 	cred->cr_ops = ops;
648 	cred->cr_expire = jiffies;
649 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
650 	cred->cr_magic = RPCAUTH_CRED_MAGIC;
651 #endif
652 	cred->cr_uid = acred->uid;
653 }
654 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
655 
656 struct rpc_cred *
657 rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags)
658 {
659 	dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
660 			cred->cr_auth->au_ops->au_name, cred);
661 	return get_rpccred(cred);
662 }
663 EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
664 
665 static struct rpc_cred *
666 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
667 {
668 	struct rpc_auth *auth = task->tk_client->cl_auth;
669 	struct auth_cred acred = {
670 		.uid = GLOBAL_ROOT_UID,
671 		.gid = GLOBAL_ROOT_GID,
672 	};
673 
674 	dprintk("RPC: %5u looking up %s cred\n",
675 		task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
676 	return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
677 }
678 
679 static struct rpc_cred *
680 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
681 {
682 	struct rpc_auth *auth = task->tk_client->cl_auth;
683 
684 	dprintk("RPC: %5u looking up %s cred\n",
685 		task->tk_pid, auth->au_ops->au_name);
686 	return rpcauth_lookupcred(auth, lookupflags);
687 }
688 
689 static int
690 rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
691 {
692 	struct rpc_rqst *req = task->tk_rqstp;
693 	struct rpc_cred *new;
694 	int lookupflags = 0;
695 
696 	if (flags & RPC_TASK_ASYNC)
697 		lookupflags |= RPCAUTH_LOOKUP_NEW;
698 	if (cred != NULL)
699 		new = cred->cr_ops->crbind(task, cred, lookupflags);
700 	else if (flags & RPC_TASK_ROOTCREDS)
701 		new = rpcauth_bind_root_cred(task, lookupflags);
702 	else
703 		new = rpcauth_bind_new_cred(task, lookupflags);
704 	if (IS_ERR(new))
705 		return PTR_ERR(new);
706 	if (req->rq_cred != NULL)
707 		put_rpccred(req->rq_cred);
708 	req->rq_cred = new;
709 	return 0;
710 }
711 
712 void
713 put_rpccred(struct rpc_cred *cred)
714 {
715 	/* Fast path for unhashed credentials */
716 	if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) {
717 		if (atomic_dec_and_test(&cred->cr_count))
718 			cred->cr_ops->crdestroy(cred);
719 		return;
720 	}
721 
722 	if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
723 		return;
724 	if (!list_empty(&cred->cr_lru)) {
725 		number_cred_unused--;
726 		list_del_init(&cred->cr_lru);
727 	}
728 	if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
729 		if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
730 			cred->cr_expire = jiffies;
731 			list_add_tail(&cred->cr_lru, &cred_unused);
732 			number_cred_unused++;
733 			goto out_nodestroy;
734 		}
735 		if (!rpcauth_unhash_cred(cred)) {
736 			/* We were hashed and someone looked us up... */
737 			goto out_nodestroy;
738 		}
739 	}
740 	spin_unlock(&rpc_credcache_lock);
741 	cred->cr_ops->crdestroy(cred);
742 	return;
743 out_nodestroy:
744 	spin_unlock(&rpc_credcache_lock);
745 }
746 EXPORT_SYMBOL_GPL(put_rpccred);
747 
748 __be32 *
749 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
750 {
751 	struct rpc_cred	*cred = task->tk_rqstp->rq_cred;
752 
753 	dprintk("RPC: %5u marshaling %s cred %p\n",
754 		task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
755 
756 	return cred->cr_ops->crmarshal(task, p);
757 }
758 
759 __be32 *
760 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
761 {
762 	struct rpc_cred	*cred = task->tk_rqstp->rq_cred;
763 
764 	dprintk("RPC: %5u validating %s cred %p\n",
765 		task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
766 
767 	return cred->cr_ops->crvalidate(task, p);
768 }
769 
770 static void rpcauth_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
771 				   __be32 *data, void *obj)
772 {
773 	struct xdr_stream xdr;
774 
775 	xdr_init_encode(&xdr, &rqstp->rq_snd_buf, data);
776 	encode(rqstp, &xdr, obj);
777 }
778 
779 int
780 rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp,
781 		__be32 *data, void *obj)
782 {
783 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
784 
785 	dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
786 			task->tk_pid, cred->cr_ops->cr_name, cred);
787 	if (cred->cr_ops->crwrap_req)
788 		return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
789 	/* By default, we encode the arguments normally. */
790 	rpcauth_wrap_req_encode(encode, rqstp, data, obj);
791 	return 0;
792 }
793 
794 static int
795 rpcauth_unwrap_req_decode(kxdrdproc_t decode, struct rpc_rqst *rqstp,
796 			  __be32 *data, void *obj)
797 {
798 	struct xdr_stream xdr;
799 
800 	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, data);
801 	return decode(rqstp, &xdr, obj);
802 }
803 
804 int
805 rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp,
806 		__be32 *data, void *obj)
807 {
808 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
809 
810 	dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
811 			task->tk_pid, cred->cr_ops->cr_name, cred);
812 	if (cred->cr_ops->crunwrap_resp)
813 		return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
814 						   data, obj);
815 	/* By default, we decode the arguments normally. */
816 	return rpcauth_unwrap_req_decode(decode, rqstp, data, obj);
817 }
818 
819 int
820 rpcauth_refreshcred(struct rpc_task *task)
821 {
822 	struct rpc_cred	*cred;
823 	int err;
824 
825 	cred = task->tk_rqstp->rq_cred;
826 	if (cred == NULL) {
827 		err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
828 		if (err < 0)
829 			goto out;
830 		cred = task->tk_rqstp->rq_cred;
831 	}
832 	dprintk("RPC: %5u refreshing %s cred %p\n",
833 		task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
834 
835 	err = cred->cr_ops->crrefresh(task);
836 out:
837 	if (err < 0)
838 		task->tk_status = err;
839 	return err;
840 }
841 
842 void
843 rpcauth_invalcred(struct rpc_task *task)
844 {
845 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
846 
847 	dprintk("RPC: %5u invalidating %s cred %p\n",
848 		task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
849 	if (cred)
850 		clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
851 }
852 
853 int
854 rpcauth_uptodatecred(struct rpc_task *task)
855 {
856 	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
857 
858 	return cred == NULL ||
859 		test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
860 }
861 
862 static struct shrinker rpc_cred_shrinker = {
863 	.count_objects = rpcauth_cache_shrink_count,
864 	.scan_objects = rpcauth_cache_shrink_scan,
865 	.seeks = DEFAULT_SEEKS,
866 };
867 
868 int __init rpcauth_init_module(void)
869 {
870 	int err;
871 
872 	err = rpc_init_authunix();
873 	if (err < 0)
874 		goto out1;
875 	err = rpc_init_generic_auth();
876 	if (err < 0)
877 		goto out2;
878 	register_shrinker(&rpc_cred_shrinker);
879 	return 0;
880 out2:
881 	rpc_destroy_authunix();
882 out1:
883 	return err;
884 }
885 
886 void rpcauth_remove_module(void)
887 {
888 	rpc_destroy_authunix();
889 	rpc_destroy_generic_auth();
890 	unregister_shrinker(&rpc_cred_shrinker);
891 }
892