Merge tag 'acpi-5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[sfrench/cifs-2.6.git] / net / sunrpc / auth.c
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/cred.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/errno.h>
15 #include <linux/hash.h>
16 #include <linux/sunrpc/clnt.h>
17 #include <linux/sunrpc/gss_api.h>
18 #include <linux/spinlock.h>
19
20 #include <trace/events/sunrpc.h>
21
22 #define RPC_CREDCACHE_DEFAULT_HASHBITS  (4)
23 struct rpc_cred_cache {
24         struct hlist_head       *hashtable;
25         unsigned int            hashbits;
26         spinlock_t              lock;
27 };
28
29 static unsigned int auth_hashbits = RPC_CREDCACHE_DEFAULT_HASHBITS;
30
31 static const struct rpc_authops __rcu *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
32         [RPC_AUTH_NULL] = (const struct rpc_authops __force __rcu *)&authnull_ops,
33         [RPC_AUTH_UNIX] = (const struct rpc_authops __force __rcu *)&authunix_ops,
34         NULL,                   /* others can be loadable modules */
35 };
36
37 static LIST_HEAD(cred_unused);
38 static unsigned long number_cred_unused;
39
40 static struct cred machine_cred = {
41         .usage = ATOMIC_INIT(1),
42 #ifdef CONFIG_DEBUG_CREDENTIALS
43         .magic = CRED_MAGIC,
44 #endif
45 };
46
47 /*
48  * Return the machine_cred pointer to be used whenever
49  * the a generic machine credential is needed.
50  */
51 const struct cred *rpc_machine_cred(void)
52 {
53         return &machine_cred;
54 }
55 EXPORT_SYMBOL_GPL(rpc_machine_cred);
56
57 #define MAX_HASHTABLE_BITS (14)
58 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
59 {
60         unsigned long num;
61         unsigned int nbits;
62         int ret;
63
64         if (!val)
65                 goto out_inval;
66         ret = kstrtoul(val, 0, &num);
67         if (ret)
68                 goto out_inval;
69         nbits = fls(num - 1);
70         if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
71                 goto out_inval;
72         *(unsigned int *)kp->arg = nbits;
73         return 0;
74 out_inval:
75         return -EINVAL;
76 }
77
78 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
79 {
80         unsigned int nbits;
81
82         nbits = *(unsigned int *)kp->arg;
83         return sprintf(buffer, "%u", 1U << nbits);
84 }
85
86 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
87
88 static const struct kernel_param_ops param_ops_hashtbl_sz = {
89         .set = param_set_hashtbl_sz,
90         .get = param_get_hashtbl_sz,
91 };
92
93 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
94 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
95
96 static unsigned long auth_max_cred_cachesize = ULONG_MAX;
97 module_param(auth_max_cred_cachesize, ulong, 0644);
98 MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size");
99
100 static u32
101 pseudoflavor_to_flavor(u32 flavor) {
102         if (flavor > RPC_AUTH_MAXFLAVOR)
103                 return RPC_AUTH_GSS;
104         return flavor;
105 }
106
107 int
108 rpcauth_register(const struct rpc_authops *ops)
109 {
110         const struct rpc_authops *old;
111         rpc_authflavor_t flavor;
112
113         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
114                 return -EINVAL;
115         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], NULL, ops);
116         if (old == NULL || old == ops)
117                 return 0;
118         return -EPERM;
119 }
120 EXPORT_SYMBOL_GPL(rpcauth_register);
121
122 int
123 rpcauth_unregister(const struct rpc_authops *ops)
124 {
125         const struct rpc_authops *old;
126         rpc_authflavor_t flavor;
127
128         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
129                 return -EINVAL;
130
131         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], ops, NULL);
132         if (old == ops || old == NULL)
133                 return 0;
134         return -EPERM;
135 }
136 EXPORT_SYMBOL_GPL(rpcauth_unregister);
137
138 static const struct rpc_authops *
139 rpcauth_get_authops(rpc_authflavor_t flavor)
140 {
141         const struct rpc_authops *ops;
142
143         if (flavor >= RPC_AUTH_MAXFLAVOR)
144                 return NULL;
145
146         rcu_read_lock();
147         ops = rcu_dereference(auth_flavors[flavor]);
148         if (ops == NULL) {
149                 rcu_read_unlock();
150                 request_module("rpc-auth-%u", flavor);
151                 rcu_read_lock();
152                 ops = rcu_dereference(auth_flavors[flavor]);
153                 if (ops == NULL)
154                         goto out;
155         }
156         if (!try_module_get(ops->owner))
157                 ops = NULL;
158 out:
159         rcu_read_unlock();
160         return ops;
161 }
162
163 static void
164 rpcauth_put_authops(const struct rpc_authops *ops)
165 {
166         module_put(ops->owner);
167 }
168
169 /**
170  * rpcauth_get_pseudoflavor - check if security flavor is supported
171  * @flavor: a security flavor
172  * @info: a GSS mech OID, quality of protection, and service value
173  *
174  * Verifies that an appropriate kernel module is available or already loaded.
175  * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
176  * not supported locally.
177  */
178 rpc_authflavor_t
179 rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
180 {
181         const struct rpc_authops *ops = rpcauth_get_authops(flavor);
182         rpc_authflavor_t pseudoflavor;
183
184         if (!ops)
185                 return RPC_AUTH_MAXFLAVOR;
186         pseudoflavor = flavor;
187         if (ops->info2flavor != NULL)
188                 pseudoflavor = ops->info2flavor(info);
189
190         rpcauth_put_authops(ops);
191         return pseudoflavor;
192 }
193 EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
194
195 /**
196  * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor
197  * @pseudoflavor: GSS pseudoflavor to match
198  * @info: rpcsec_gss_info structure to fill in
199  *
200  * Returns zero and fills in "info" if pseudoflavor matches a
201  * supported mechanism.
202  */
203 int
204 rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
205 {
206         rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor);
207         const struct rpc_authops *ops;
208         int result;
209
210         ops = rpcauth_get_authops(flavor);
211         if (ops == NULL)
212                 return -ENOENT;
213
214         result = -ENOENT;
215         if (ops->flavor2info != NULL)
216                 result = ops->flavor2info(pseudoflavor, info);
217
218         rpcauth_put_authops(ops);
219         return result;
220 }
221 EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
222
223 /**
224  * rpcauth_list_flavors - discover registered flavors and pseudoflavors
225  * @array: array to fill in
226  * @size: size of "array"
227  *
228  * Returns the number of array items filled in, or a negative errno.
229  *
230  * The returned array is not sorted by any policy.  Callers should not
231  * rely on the order of the items in the returned array.
232  */
233 int
234 rpcauth_list_flavors(rpc_authflavor_t *array, int size)
235 {
236         const struct rpc_authops *ops;
237         rpc_authflavor_t flavor, pseudos[4];
238         int i, len, result = 0;
239
240         rcu_read_lock();
241         for (flavor = 0; flavor < RPC_AUTH_MAXFLAVOR; flavor++) {
242                 ops = rcu_dereference(auth_flavors[flavor]);
243                 if (result >= size) {
244                         result = -ENOMEM;
245                         break;
246                 }
247
248                 if (ops == NULL)
249                         continue;
250                 if (ops->list_pseudoflavors == NULL) {
251                         array[result++] = ops->au_flavor;
252                         continue;
253                 }
254                 len = ops->list_pseudoflavors(pseudos, ARRAY_SIZE(pseudos));
255                 if (len < 0) {
256                         result = len;
257                         break;
258                 }
259                 for (i = 0; i < len; i++) {
260                         if (result >= size) {
261                                 result = -ENOMEM;
262                                 break;
263                         }
264                         array[result++] = pseudos[i];
265                 }
266         }
267         rcu_read_unlock();
268         return result;
269 }
270 EXPORT_SYMBOL_GPL(rpcauth_list_flavors);
271
272 struct rpc_auth *
273 rpcauth_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
274 {
275         struct rpc_auth *auth = ERR_PTR(-EINVAL);
276         const struct rpc_authops *ops;
277         u32 flavor = pseudoflavor_to_flavor(args->pseudoflavor);
278
279         ops = rpcauth_get_authops(flavor);
280         if (ops == NULL)
281                 goto out;
282
283         auth = ops->create(args, clnt);
284
285         rpcauth_put_authops(ops);
286         if (IS_ERR(auth))
287                 return auth;
288         if (clnt->cl_auth)
289                 rpcauth_release(clnt->cl_auth);
290         clnt->cl_auth = auth;
291
292 out:
293         return auth;
294 }
295 EXPORT_SYMBOL_GPL(rpcauth_create);
296
297 void
298 rpcauth_release(struct rpc_auth *auth)
299 {
300         if (!refcount_dec_and_test(&auth->au_count))
301                 return;
302         auth->au_ops->destroy(auth);
303 }
304
305 static DEFINE_SPINLOCK(rpc_credcache_lock);
306
307 /*
308  * On success, the caller is responsible for freeing the reference
309  * held by the hashtable
310  */
311 static bool
312 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
313 {
314         if (!test_and_clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
315                 return false;
316         hlist_del_rcu(&cred->cr_hash);
317         return true;
318 }
319
320 static bool
321 rpcauth_unhash_cred(struct rpc_cred *cred)
322 {
323         spinlock_t *cache_lock;
324         bool ret;
325
326         if (!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
327                 return false;
328         cache_lock = &cred->cr_auth->au_credcache->lock;
329         spin_lock(cache_lock);
330         ret = rpcauth_unhash_cred_locked(cred);
331         spin_unlock(cache_lock);
332         return ret;
333 }
334
335 /*
336  * Initialize RPC credential cache
337  */
338 int
339 rpcauth_init_credcache(struct rpc_auth *auth)
340 {
341         struct rpc_cred_cache *new;
342         unsigned int hashsize;
343
344         new = kmalloc(sizeof(*new), GFP_KERNEL);
345         if (!new)
346                 goto out_nocache;
347         new->hashbits = auth_hashbits;
348         hashsize = 1U << new->hashbits;
349         new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
350         if (!new->hashtable)
351                 goto out_nohashtbl;
352         spin_lock_init(&new->lock);
353         auth->au_credcache = new;
354         return 0;
355 out_nohashtbl:
356         kfree(new);
357 out_nocache:
358         return -ENOMEM;
359 }
360 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
361
362 char *
363 rpcauth_stringify_acceptor(struct rpc_cred *cred)
364 {
365         if (!cred->cr_ops->crstringify_acceptor)
366                 return NULL;
367         return cred->cr_ops->crstringify_acceptor(cred);
368 }
369 EXPORT_SYMBOL_GPL(rpcauth_stringify_acceptor);
370
371 /*
372  * Destroy a list of credentials
373  */
374 static inline
375 void rpcauth_destroy_credlist(struct list_head *head)
376 {
377         struct rpc_cred *cred;
378
379         while (!list_empty(head)) {
380                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
381                 list_del_init(&cred->cr_lru);
382                 put_rpccred(cred);
383         }
384 }
385
386 static void
387 rpcauth_lru_add_locked(struct rpc_cred *cred)
388 {
389         if (!list_empty(&cred->cr_lru))
390                 return;
391         number_cred_unused++;
392         list_add_tail(&cred->cr_lru, &cred_unused);
393 }
394
395 static void
396 rpcauth_lru_add(struct rpc_cred *cred)
397 {
398         if (!list_empty(&cred->cr_lru))
399                 return;
400         spin_lock(&rpc_credcache_lock);
401         rpcauth_lru_add_locked(cred);
402         spin_unlock(&rpc_credcache_lock);
403 }
404
405 static void
406 rpcauth_lru_remove_locked(struct rpc_cred *cred)
407 {
408         if (list_empty(&cred->cr_lru))
409                 return;
410         number_cred_unused--;
411         list_del_init(&cred->cr_lru);
412 }
413
414 static void
415 rpcauth_lru_remove(struct rpc_cred *cred)
416 {
417         if (list_empty(&cred->cr_lru))
418                 return;
419         spin_lock(&rpc_credcache_lock);
420         rpcauth_lru_remove_locked(cred);
421         spin_unlock(&rpc_credcache_lock);
422 }
423
424 /*
425  * Clear the RPC credential cache, and delete those credentials
426  * that are not referenced.
427  */
428 void
429 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
430 {
431         LIST_HEAD(free);
432         struct hlist_head *head;
433         struct rpc_cred *cred;
434         unsigned int hashsize = 1U << cache->hashbits;
435         int             i;
436
437         spin_lock(&rpc_credcache_lock);
438         spin_lock(&cache->lock);
439         for (i = 0; i < hashsize; i++) {
440                 head = &cache->hashtable[i];
441                 while (!hlist_empty(head)) {
442                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
443                         rpcauth_unhash_cred_locked(cred);
444                         /* Note: We now hold a reference to cred */
445                         rpcauth_lru_remove_locked(cred);
446                         list_add_tail(&cred->cr_lru, &free);
447                 }
448         }
449         spin_unlock(&cache->lock);
450         spin_unlock(&rpc_credcache_lock);
451         rpcauth_destroy_credlist(&free);
452 }
453
454 /*
455  * Destroy the RPC credential cache
456  */
457 void
458 rpcauth_destroy_credcache(struct rpc_auth *auth)
459 {
460         struct rpc_cred_cache *cache = auth->au_credcache;
461
462         if (cache) {
463                 auth->au_credcache = NULL;
464                 rpcauth_clear_credcache(cache);
465                 kfree(cache->hashtable);
466                 kfree(cache);
467         }
468 }
469 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
470
471
472 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
473
474 /*
475  * Remove stale credentials. Avoid sleeping inside the loop.
476  */
477 static long
478 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
479 {
480         struct rpc_cred *cred, *next;
481         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
482         long freed = 0;
483
484         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
485
486                 if (nr_to_scan-- == 0)
487                         break;
488                 if (refcount_read(&cred->cr_count) > 1) {
489                         rpcauth_lru_remove_locked(cred);
490                         continue;
491                 }
492                 /*
493                  * Enforce a 60 second garbage collection moratorium
494                  * Note that the cred_unused list must be time-ordered.
495                  */
496                 if (!time_in_range(cred->cr_expire, expired, jiffies))
497                         continue;
498                 if (!rpcauth_unhash_cred(cred))
499                         continue;
500
501                 rpcauth_lru_remove_locked(cred);
502                 freed++;
503                 list_add_tail(&cred->cr_lru, free);
504         }
505         return freed ? freed : SHRINK_STOP;
506 }
507
508 static unsigned long
509 rpcauth_cache_do_shrink(int nr_to_scan)
510 {
511         LIST_HEAD(free);
512         unsigned long freed;
513
514         spin_lock(&rpc_credcache_lock);
515         freed = rpcauth_prune_expired(&free, nr_to_scan);
516         spin_unlock(&rpc_credcache_lock);
517         rpcauth_destroy_credlist(&free);
518
519         return freed;
520 }
521
522 /*
523  * Run memory cache shrinker.
524  */
525 static unsigned long
526 rpcauth_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
527
528 {
529         if ((sc->gfp_mask & GFP_KERNEL) != GFP_KERNEL)
530                 return SHRINK_STOP;
531
532         /* nothing left, don't come back */
533         if (list_empty(&cred_unused))
534                 return SHRINK_STOP;
535
536         return rpcauth_cache_do_shrink(sc->nr_to_scan);
537 }
538
539 static unsigned long
540 rpcauth_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
541
542 {
543         return number_cred_unused * sysctl_vfs_cache_pressure / 100;
544 }
545
546 static void
547 rpcauth_cache_enforce_limit(void)
548 {
549         unsigned long diff;
550         unsigned int nr_to_scan;
551
552         if (number_cred_unused <= auth_max_cred_cachesize)
553                 return;
554         diff = number_cred_unused - auth_max_cred_cachesize;
555         nr_to_scan = 100;
556         if (diff < nr_to_scan)
557                 nr_to_scan = diff;
558         rpcauth_cache_do_shrink(nr_to_scan);
559 }
560
561 /*
562  * Look up a process' credentials in the authentication cache
563  */
564 struct rpc_cred *
565 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
566                 int flags, gfp_t gfp)
567 {
568         LIST_HEAD(free);
569         struct rpc_cred_cache *cache = auth->au_credcache;
570         struct rpc_cred *cred = NULL,
571                         *entry, *new;
572         unsigned int nr;
573
574         nr = auth->au_ops->hash_cred(acred, cache->hashbits);
575
576         rcu_read_lock();
577         hlist_for_each_entry_rcu(entry, &cache->hashtable[nr], cr_hash) {
578                 if (!entry->cr_ops->crmatch(acred, entry, flags))
579                         continue;
580                 cred = get_rpccred(entry);
581                 if (cred)
582                         break;
583         }
584         rcu_read_unlock();
585
586         if (cred != NULL)
587                 goto found;
588
589         new = auth->au_ops->crcreate(auth, acred, flags, gfp);
590         if (IS_ERR(new)) {
591                 cred = new;
592                 goto out;
593         }
594
595         spin_lock(&cache->lock);
596         hlist_for_each_entry(entry, &cache->hashtable[nr], cr_hash) {
597                 if (!entry->cr_ops->crmatch(acred, entry, flags))
598                         continue;
599                 cred = get_rpccred(entry);
600                 if (cred)
601                         break;
602         }
603         if (cred == NULL) {
604                 cred = new;
605                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
606                 refcount_inc(&cred->cr_count);
607                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
608         } else
609                 list_add_tail(&new->cr_lru, &free);
610         spin_unlock(&cache->lock);
611         rpcauth_cache_enforce_limit();
612 found:
613         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
614             cred->cr_ops->cr_init != NULL &&
615             !(flags & RPCAUTH_LOOKUP_NEW)) {
616                 int res = cred->cr_ops->cr_init(auth, cred);
617                 if (res < 0) {
618                         put_rpccred(cred);
619                         cred = ERR_PTR(res);
620                 }
621         }
622         rpcauth_destroy_credlist(&free);
623 out:
624         return cred;
625 }
626 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
627
628 struct rpc_cred *
629 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
630 {
631         struct auth_cred acred;
632         struct rpc_cred *ret;
633         const struct cred *cred = current_cred();
634
635         memset(&acred, 0, sizeof(acred));
636         acred.cred = cred;
637         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
638         return ret;
639 }
640 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
641
642 void
643 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
644                   struct rpc_auth *auth, const struct rpc_credops *ops)
645 {
646         INIT_HLIST_NODE(&cred->cr_hash);
647         INIT_LIST_HEAD(&cred->cr_lru);
648         refcount_set(&cred->cr_count, 1);
649         cred->cr_auth = auth;
650         cred->cr_flags = 0;
651         cred->cr_ops = ops;
652         cred->cr_expire = jiffies;
653         cred->cr_cred = get_cred(acred->cred);
654 }
655 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
656
657 static struct rpc_cred *
658 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
659 {
660         struct rpc_auth *auth = task->tk_client->cl_auth;
661         struct auth_cred acred = {
662                 .cred = get_task_cred(&init_task),
663         };
664         struct rpc_cred *ret;
665
666         ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
667         put_cred(acred.cred);
668         return ret;
669 }
670
671 static struct rpc_cred *
672 rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags)
673 {
674         struct rpc_auth *auth = task->tk_client->cl_auth;
675         struct auth_cred acred = {
676                 .principal = task->tk_client->cl_principal,
677                 .cred = init_task.cred,
678         };
679
680         if (!acred.principal)
681                 return NULL;
682         return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
683 }
684
685 static struct rpc_cred *
686 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
687 {
688         struct rpc_auth *auth = task->tk_client->cl_auth;
689
690         return rpcauth_lookupcred(auth, lookupflags);
691 }
692
693 static int
694 rpcauth_bindcred(struct rpc_task *task, const struct cred *cred, int flags)
695 {
696         struct rpc_rqst *req = task->tk_rqstp;
697         struct rpc_cred *new = NULL;
698         int lookupflags = 0;
699         struct rpc_auth *auth = task->tk_client->cl_auth;
700         struct auth_cred acred = {
701                 .cred = cred,
702         };
703
704         if (flags & RPC_TASK_ASYNC)
705                 lookupflags |= RPCAUTH_LOOKUP_NEW;
706         if (task->tk_op_cred)
707                 /* Task must use exactly this rpc_cred */
708                 new = get_rpccred(task->tk_op_cred);
709         else if (cred != NULL && cred != &machine_cred)
710                 new = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
711         else if (cred == &machine_cred)
712                 new = rpcauth_bind_machine_cred(task, lookupflags);
713
714         /* If machine cred couldn't be bound, try a root cred */
715         if (new)
716                 ;
717         else if (cred == &machine_cred || (flags & RPC_TASK_ROOTCREDS))
718                 new = rpcauth_bind_root_cred(task, lookupflags);
719         else if (flags & RPC_TASK_NULLCREDS)
720                 new = authnull_ops.lookup_cred(NULL, NULL, 0);
721         else
722                 new = rpcauth_bind_new_cred(task, lookupflags);
723         if (IS_ERR(new))
724                 return PTR_ERR(new);
725         put_rpccred(req->rq_cred);
726         req->rq_cred = new;
727         return 0;
728 }
729
730 void
731 put_rpccred(struct rpc_cred *cred)
732 {
733         if (cred == NULL)
734                 return;
735         rcu_read_lock();
736         if (refcount_dec_and_test(&cred->cr_count))
737                 goto destroy;
738         if (refcount_read(&cred->cr_count) != 1 ||
739             !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
740                 goto out;
741         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
742                 cred->cr_expire = jiffies;
743                 rpcauth_lru_add(cred);
744                 /* Race breaker */
745                 if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)))
746                         rpcauth_lru_remove(cred);
747         } else if (rpcauth_unhash_cred(cred)) {
748                 rpcauth_lru_remove(cred);
749                 if (refcount_dec_and_test(&cred->cr_count))
750                         goto destroy;
751         }
752 out:
753         rcu_read_unlock();
754         return;
755 destroy:
756         rcu_read_unlock();
757         cred->cr_ops->crdestroy(cred);
758 }
759 EXPORT_SYMBOL_GPL(put_rpccred);
760
761 /**
762  * rpcauth_marshcred - Append RPC credential to end of @xdr
763  * @task: controlling RPC task
764  * @xdr: xdr_stream containing initial portion of RPC Call header
765  *
766  * On success, an appropriate verifier is added to @xdr, @xdr is
767  * updated to point past the verifier, and zero is returned.
768  * Otherwise, @xdr is in an undefined state and a negative errno
769  * is returned.
770  */
771 int rpcauth_marshcred(struct rpc_task *task, struct xdr_stream *xdr)
772 {
773         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
774
775         return ops->crmarshal(task, xdr);
776 }
777
778 /**
779  * rpcauth_wrap_req_encode - XDR encode the RPC procedure
780  * @task: controlling RPC task
781  * @xdr: stream where on-the-wire bytes are to be marshalled
782  *
783  * On success, @xdr contains the encoded and wrapped message.
784  * Otherwise, @xdr is in an undefined state.
785  */
786 int rpcauth_wrap_req_encode(struct rpc_task *task, struct xdr_stream *xdr)
787 {
788         kxdreproc_t encode = task->tk_msg.rpc_proc->p_encode;
789
790         encode(task->tk_rqstp, xdr, task->tk_msg.rpc_argp);
791         return 0;
792 }
793 EXPORT_SYMBOL_GPL(rpcauth_wrap_req_encode);
794
795 /**
796  * rpcauth_wrap_req - XDR encode and wrap the RPC procedure
797  * @task: controlling RPC task
798  * @xdr: stream where on-the-wire bytes are to be marshalled
799  *
800  * On success, @xdr contains the encoded and wrapped message,
801  * and zero is returned. Otherwise, @xdr is in an undefined
802  * state and a negative errno is returned.
803  */
804 int rpcauth_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
805 {
806         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
807
808         return ops->crwrap_req(task, xdr);
809 }
810
811 /**
812  * rpcauth_checkverf - Validate verifier in RPC Reply header
813  * @task: controlling RPC task
814  * @xdr: xdr_stream containing RPC Reply header
815  *
816  * On success, @xdr is updated to point past the verifier and
817  * zero is returned. Otherwise, @xdr is in an undefined state
818  * and a negative errno is returned.
819  */
820 int
821 rpcauth_checkverf(struct rpc_task *task, struct xdr_stream *xdr)
822 {
823         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
824
825         return ops->crvalidate(task, xdr);
826 }
827
828 /**
829  * rpcauth_unwrap_resp_decode - Invoke XDR decode function
830  * @task: controlling RPC task
831  * @xdr: stream where the Reply message resides
832  *
833  * Returns zero on success; otherwise a negative errno is returned.
834  */
835 int
836 rpcauth_unwrap_resp_decode(struct rpc_task *task, struct xdr_stream *xdr)
837 {
838         kxdrdproc_t decode = task->tk_msg.rpc_proc->p_decode;
839
840         return decode(task->tk_rqstp, xdr, task->tk_msg.rpc_resp);
841 }
842 EXPORT_SYMBOL_GPL(rpcauth_unwrap_resp_decode);
843
844 /**
845  * rpcauth_unwrap_resp - Invoke unwrap and decode function for the cred
846  * @task: controlling RPC task
847  * @xdr: stream where the Reply message resides
848  *
849  * Returns zero on success; otherwise a negative errno is returned.
850  */
851 int
852 rpcauth_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr)
853 {
854         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
855
856         return ops->crunwrap_resp(task, xdr);
857 }
858
859 bool
860 rpcauth_xmit_need_reencode(struct rpc_task *task)
861 {
862         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
863
864         if (!cred || !cred->cr_ops->crneed_reencode)
865                 return false;
866         return cred->cr_ops->crneed_reencode(task);
867 }
868
869 int
870 rpcauth_refreshcred(struct rpc_task *task)
871 {
872         struct rpc_cred *cred;
873         int err;
874
875         cred = task->tk_rqstp->rq_cred;
876         if (cred == NULL) {
877                 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
878                 if (err < 0)
879                         goto out;
880                 cred = task->tk_rqstp->rq_cred;
881         }
882
883         err = cred->cr_ops->crrefresh(task);
884 out:
885         if (err < 0)
886                 task->tk_status = err;
887         return err;
888 }
889
890 void
891 rpcauth_invalcred(struct rpc_task *task)
892 {
893         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
894
895         if (cred)
896                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
897 }
898
899 int
900 rpcauth_uptodatecred(struct rpc_task *task)
901 {
902         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
903
904         return cred == NULL ||
905                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
906 }
907
908 static struct shrinker rpc_cred_shrinker = {
909         .count_objects = rpcauth_cache_shrink_count,
910         .scan_objects = rpcauth_cache_shrink_scan,
911         .seeks = DEFAULT_SEEKS,
912 };
913
914 int __init rpcauth_init_module(void)
915 {
916         int err;
917
918         err = rpc_init_authunix();
919         if (err < 0)
920                 goto out1;
921         err = register_shrinker(&rpc_cred_shrinker);
922         if (err < 0)
923                 goto out2;
924         return 0;
925 out2:
926         rpc_destroy_authunix();
927 out1:
928         return err;
929 }
930
931 void rpcauth_remove_module(void)
932 {
933         rpc_destroy_authunix();
934         unregister_shrinker(&rpc_cred_shrinker);
935 }