Merge tag 'for-v6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux...
[platform/kernel/linux-rpi.git] / net / sunrpc / auth.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * linux/net/sunrpc/auth.c
4  *
5  * Generic RPC client authentication API.
6  *
7  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
8  */
9
10 #include <linux/types.h>
11 #include <linux/sched.h>
12 #include <linux/cred.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/errno.h>
16 #include <linux/hash.h>
17 #include <linux/sunrpc/clnt.h>
18 #include <linux/sunrpc/gss_api.h>
19 #include <linux/spinlock.h>
20
21 #include <trace/events/sunrpc.h>
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 const struct rpc_authops __rcu *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
33         [RPC_AUTH_NULL] = (const struct rpc_authops __force __rcu *)&authnull_ops,
34         [RPC_AUTH_UNIX] = (const struct rpc_authops __force __rcu *)&authunix_ops,
35         [RPC_AUTH_TLS]  = (const struct rpc_authops __force __rcu *)&authtls_ops,
36 };
37
38 static LIST_HEAD(cred_unused);
39 static unsigned long number_cred_unused;
40
41 static struct cred machine_cred = {
42         .usage = ATOMIC_INIT(1),
43 #ifdef CONFIG_DEBUG_CREDENTIALS
44         .magic = CRED_MAGIC,
45 #endif
46 };
47
48 /*
49  * Return the machine_cred pointer to be used whenever
50  * the a generic machine credential is needed.
51  */
52 const struct cred *rpc_machine_cred(void)
53 {
54         return &machine_cred;
55 }
56 EXPORT_SYMBOL_GPL(rpc_machine_cred);
57
58 #define MAX_HASHTABLE_BITS (14)
59 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
60 {
61         unsigned long num;
62         unsigned int nbits;
63         int ret;
64
65         if (!val)
66                 goto out_inval;
67         ret = kstrtoul(val, 0, &num);
68         if (ret)
69                 goto out_inval;
70         nbits = fls(num - 1);
71         if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
72                 goto out_inval;
73         *(unsigned int *)kp->arg = nbits;
74         return 0;
75 out_inval:
76         return -EINVAL;
77 }
78
79 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
80 {
81         unsigned int nbits;
82
83         nbits = *(unsigned int *)kp->arg;
84         return sprintf(buffer, "%u\n", 1U << nbits);
85 }
86
87 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
88
89 static const struct kernel_param_ops param_ops_hashtbl_sz = {
90         .set = param_set_hashtbl_sz,
91         .get = param_get_hashtbl_sz,
92 };
93
94 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
95 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
96
97 static unsigned long auth_max_cred_cachesize = ULONG_MAX;
98 module_param(auth_max_cred_cachesize, ulong, 0644);
99 MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size");
100
101 static u32
102 pseudoflavor_to_flavor(u32 flavor) {
103         if (flavor > RPC_AUTH_MAXFLAVOR)
104                 return RPC_AUTH_GSS;
105         return flavor;
106 }
107
108 int
109 rpcauth_register(const struct rpc_authops *ops)
110 {
111         const struct rpc_authops *old;
112         rpc_authflavor_t flavor;
113
114         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
115                 return -EINVAL;
116         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], NULL, ops);
117         if (old == NULL || old == ops)
118                 return 0;
119         return -EPERM;
120 }
121 EXPORT_SYMBOL_GPL(rpcauth_register);
122
123 int
124 rpcauth_unregister(const struct rpc_authops *ops)
125 {
126         const struct rpc_authops *old;
127         rpc_authflavor_t flavor;
128
129         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
130                 return -EINVAL;
131
132         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], ops, NULL);
133         if (old == ops || old == NULL)
134                 return 0;
135         return -EPERM;
136 }
137 EXPORT_SYMBOL_GPL(rpcauth_unregister);
138
139 static const struct rpc_authops *
140 rpcauth_get_authops(rpc_authflavor_t flavor)
141 {
142         const struct rpc_authops *ops;
143
144         if (flavor >= RPC_AUTH_MAXFLAVOR)
145                 return NULL;
146
147         rcu_read_lock();
148         ops = rcu_dereference(auth_flavors[flavor]);
149         if (ops == NULL) {
150                 rcu_read_unlock();
151                 request_module("rpc-auth-%u", flavor);
152                 rcu_read_lock();
153                 ops = rcu_dereference(auth_flavors[flavor]);
154                 if (ops == NULL)
155                         goto out;
156         }
157         if (!try_module_get(ops->owner))
158                 ops = NULL;
159 out:
160         rcu_read_unlock();
161         return ops;
162 }
163
164 static void
165 rpcauth_put_authops(const struct rpc_authops *ops)
166 {
167         module_put(ops->owner);
168 }
169
170 /**
171  * rpcauth_get_pseudoflavor - check if security flavor is supported
172  * @flavor: a security flavor
173  * @info: a GSS mech OID, quality of protection, and service value
174  *
175  * Verifies that an appropriate kernel module is available or already loaded.
176  * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
177  * not supported locally.
178  */
179 rpc_authflavor_t
180 rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
181 {
182         const struct rpc_authops *ops = rpcauth_get_authops(flavor);
183         rpc_authflavor_t pseudoflavor;
184
185         if (!ops)
186                 return RPC_AUTH_MAXFLAVOR;
187         pseudoflavor = flavor;
188         if (ops->info2flavor != NULL)
189                 pseudoflavor = ops->info2flavor(info);
190
191         rpcauth_put_authops(ops);
192         return pseudoflavor;
193 }
194 EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
195
196 /**
197  * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor
198  * @pseudoflavor: GSS pseudoflavor to match
199  * @info: rpcsec_gss_info structure to fill in
200  *
201  * Returns zero and fills in "info" if pseudoflavor matches a
202  * supported mechanism.
203  */
204 int
205 rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
206 {
207         rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor);
208         const struct rpc_authops *ops;
209         int result;
210
211         ops = rpcauth_get_authops(flavor);
212         if (ops == NULL)
213                 return -ENOENT;
214
215         result = -ENOENT;
216         if (ops->flavor2info != NULL)
217                 result = ops->flavor2info(pseudoflavor, info);
218
219         rpcauth_put_authops(ops);
220         return result;
221 }
222 EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
223
224 struct rpc_auth *
225 rpcauth_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
226 {
227         struct rpc_auth *auth = ERR_PTR(-EINVAL);
228         const struct rpc_authops *ops;
229         u32 flavor = pseudoflavor_to_flavor(args->pseudoflavor);
230
231         ops = rpcauth_get_authops(flavor);
232         if (ops == NULL)
233                 goto out;
234
235         auth = ops->create(args, clnt);
236
237         rpcauth_put_authops(ops);
238         if (IS_ERR(auth))
239                 return auth;
240         if (clnt->cl_auth)
241                 rpcauth_release(clnt->cl_auth);
242         clnt->cl_auth = auth;
243
244 out:
245         return auth;
246 }
247 EXPORT_SYMBOL_GPL(rpcauth_create);
248
249 void
250 rpcauth_release(struct rpc_auth *auth)
251 {
252         if (!refcount_dec_and_test(&auth->au_count))
253                 return;
254         auth->au_ops->destroy(auth);
255 }
256
257 static DEFINE_SPINLOCK(rpc_credcache_lock);
258
259 /*
260  * On success, the caller is responsible for freeing the reference
261  * held by the hashtable
262  */
263 static bool
264 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
265 {
266         if (!test_and_clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
267                 return false;
268         hlist_del_rcu(&cred->cr_hash);
269         return true;
270 }
271
272 static bool
273 rpcauth_unhash_cred(struct rpc_cred *cred)
274 {
275         spinlock_t *cache_lock;
276         bool ret;
277
278         if (!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
279                 return false;
280         cache_lock = &cred->cr_auth->au_credcache->lock;
281         spin_lock(cache_lock);
282         ret = rpcauth_unhash_cred_locked(cred);
283         spin_unlock(cache_lock);
284         return ret;
285 }
286
287 /*
288  * Initialize RPC credential cache
289  */
290 int
291 rpcauth_init_credcache(struct rpc_auth *auth)
292 {
293         struct rpc_cred_cache *new;
294         unsigned int hashsize;
295
296         new = kmalloc(sizeof(*new), GFP_KERNEL);
297         if (!new)
298                 goto out_nocache;
299         new->hashbits = auth_hashbits;
300         hashsize = 1U << new->hashbits;
301         new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
302         if (!new->hashtable)
303                 goto out_nohashtbl;
304         spin_lock_init(&new->lock);
305         auth->au_credcache = new;
306         return 0;
307 out_nohashtbl:
308         kfree(new);
309 out_nocache:
310         return -ENOMEM;
311 }
312 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
313
314 char *
315 rpcauth_stringify_acceptor(struct rpc_cred *cred)
316 {
317         if (!cred->cr_ops->crstringify_acceptor)
318                 return NULL;
319         return cred->cr_ops->crstringify_acceptor(cred);
320 }
321 EXPORT_SYMBOL_GPL(rpcauth_stringify_acceptor);
322
323 /*
324  * Destroy a list of credentials
325  */
326 static inline
327 void rpcauth_destroy_credlist(struct list_head *head)
328 {
329         struct rpc_cred *cred;
330
331         while (!list_empty(head)) {
332                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
333                 list_del_init(&cred->cr_lru);
334                 put_rpccred(cred);
335         }
336 }
337
338 static void
339 rpcauth_lru_add_locked(struct rpc_cred *cred)
340 {
341         if (!list_empty(&cred->cr_lru))
342                 return;
343         number_cred_unused++;
344         list_add_tail(&cred->cr_lru, &cred_unused);
345 }
346
347 static void
348 rpcauth_lru_add(struct rpc_cred *cred)
349 {
350         if (!list_empty(&cred->cr_lru))
351                 return;
352         spin_lock(&rpc_credcache_lock);
353         rpcauth_lru_add_locked(cred);
354         spin_unlock(&rpc_credcache_lock);
355 }
356
357 static void
358 rpcauth_lru_remove_locked(struct rpc_cred *cred)
359 {
360         if (list_empty(&cred->cr_lru))
361                 return;
362         number_cred_unused--;
363         list_del_init(&cred->cr_lru);
364 }
365
366 static void
367 rpcauth_lru_remove(struct rpc_cred *cred)
368 {
369         if (list_empty(&cred->cr_lru))
370                 return;
371         spin_lock(&rpc_credcache_lock);
372         rpcauth_lru_remove_locked(cred);
373         spin_unlock(&rpc_credcache_lock);
374 }
375
376 /*
377  * Clear the RPC credential cache, and delete those credentials
378  * that are not referenced.
379  */
380 void
381 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
382 {
383         LIST_HEAD(free);
384         struct hlist_head *head;
385         struct rpc_cred *cred;
386         unsigned int hashsize = 1U << cache->hashbits;
387         int             i;
388
389         spin_lock(&rpc_credcache_lock);
390         spin_lock(&cache->lock);
391         for (i = 0; i < hashsize; i++) {
392                 head = &cache->hashtable[i];
393                 while (!hlist_empty(head)) {
394                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
395                         rpcauth_unhash_cred_locked(cred);
396                         /* Note: We now hold a reference to cred */
397                         rpcauth_lru_remove_locked(cred);
398                         list_add_tail(&cred->cr_lru, &free);
399                 }
400         }
401         spin_unlock(&cache->lock);
402         spin_unlock(&rpc_credcache_lock);
403         rpcauth_destroy_credlist(&free);
404 }
405
406 /*
407  * Destroy the RPC credential cache
408  */
409 void
410 rpcauth_destroy_credcache(struct rpc_auth *auth)
411 {
412         struct rpc_cred_cache *cache = auth->au_credcache;
413
414         if (cache) {
415                 auth->au_credcache = NULL;
416                 rpcauth_clear_credcache(cache);
417                 kfree(cache->hashtable);
418                 kfree(cache);
419         }
420 }
421 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
422
423
424 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
425
426 /*
427  * Remove stale credentials. Avoid sleeping inside the loop.
428  */
429 static long
430 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
431 {
432         struct rpc_cred *cred, *next;
433         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
434         long freed = 0;
435
436         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
437
438                 if (nr_to_scan-- == 0)
439                         break;
440                 if (refcount_read(&cred->cr_count) > 1) {
441                         rpcauth_lru_remove_locked(cred);
442                         continue;
443                 }
444                 /*
445                  * Enforce a 60 second garbage collection moratorium
446                  * Note that the cred_unused list must be time-ordered.
447                  */
448                 if (time_in_range(cred->cr_expire, expired, jiffies))
449                         continue;
450                 if (!rpcauth_unhash_cred(cred))
451                         continue;
452
453                 rpcauth_lru_remove_locked(cred);
454                 freed++;
455                 list_add_tail(&cred->cr_lru, free);
456         }
457         return freed ? freed : SHRINK_STOP;
458 }
459
460 static unsigned long
461 rpcauth_cache_do_shrink(int nr_to_scan)
462 {
463         LIST_HEAD(free);
464         unsigned long freed;
465
466         spin_lock(&rpc_credcache_lock);
467         freed = rpcauth_prune_expired(&free, nr_to_scan);
468         spin_unlock(&rpc_credcache_lock);
469         rpcauth_destroy_credlist(&free);
470
471         return freed;
472 }
473
474 /*
475  * Run memory cache shrinker.
476  */
477 static unsigned long
478 rpcauth_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
479
480 {
481         if ((sc->gfp_mask & GFP_KERNEL) != GFP_KERNEL)
482                 return SHRINK_STOP;
483
484         /* nothing left, don't come back */
485         if (list_empty(&cred_unused))
486                 return SHRINK_STOP;
487
488         return rpcauth_cache_do_shrink(sc->nr_to_scan);
489 }
490
491 static unsigned long
492 rpcauth_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
493
494 {
495         return number_cred_unused * sysctl_vfs_cache_pressure / 100;
496 }
497
498 static void
499 rpcauth_cache_enforce_limit(void)
500 {
501         unsigned long diff;
502         unsigned int nr_to_scan;
503
504         if (number_cred_unused <= auth_max_cred_cachesize)
505                 return;
506         diff = number_cred_unused - auth_max_cred_cachesize;
507         nr_to_scan = 100;
508         if (diff < nr_to_scan)
509                 nr_to_scan = diff;
510         rpcauth_cache_do_shrink(nr_to_scan);
511 }
512
513 /*
514  * Look up a process' credentials in the authentication cache
515  */
516 struct rpc_cred *
517 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
518                 int flags, gfp_t gfp)
519 {
520         LIST_HEAD(free);
521         struct rpc_cred_cache *cache = auth->au_credcache;
522         struct rpc_cred *cred = NULL,
523                         *entry, *new;
524         unsigned int nr;
525
526         nr = auth->au_ops->hash_cred(acred, cache->hashbits);
527
528         rcu_read_lock();
529         hlist_for_each_entry_rcu(entry, &cache->hashtable[nr], cr_hash) {
530                 if (!entry->cr_ops->crmatch(acred, entry, flags))
531                         continue;
532                 cred = get_rpccred(entry);
533                 if (cred)
534                         break;
535         }
536         rcu_read_unlock();
537
538         if (cred != NULL)
539                 goto found;
540
541         new = auth->au_ops->crcreate(auth, acred, flags, gfp);
542         if (IS_ERR(new)) {
543                 cred = new;
544                 goto out;
545         }
546
547         spin_lock(&cache->lock);
548         hlist_for_each_entry(entry, &cache->hashtable[nr], cr_hash) {
549                 if (!entry->cr_ops->crmatch(acred, entry, flags))
550                         continue;
551                 cred = get_rpccred(entry);
552                 if (cred)
553                         break;
554         }
555         if (cred == NULL) {
556                 cred = new;
557                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
558                 refcount_inc(&cred->cr_count);
559                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
560         } else
561                 list_add_tail(&new->cr_lru, &free);
562         spin_unlock(&cache->lock);
563         rpcauth_cache_enforce_limit();
564 found:
565         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
566             cred->cr_ops->cr_init != NULL &&
567             !(flags & RPCAUTH_LOOKUP_NEW)) {
568                 int res = cred->cr_ops->cr_init(auth, cred);
569                 if (res < 0) {
570                         put_rpccred(cred);
571                         cred = ERR_PTR(res);
572                 }
573         }
574         rpcauth_destroy_credlist(&free);
575 out:
576         return cred;
577 }
578 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
579
580 struct rpc_cred *
581 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
582 {
583         struct auth_cred acred;
584         struct rpc_cred *ret;
585         const struct cred *cred = current_cred();
586
587         memset(&acred, 0, sizeof(acred));
588         acred.cred = cred;
589         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
590         return ret;
591 }
592 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
593
594 void
595 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
596                   struct rpc_auth *auth, const struct rpc_credops *ops)
597 {
598         INIT_HLIST_NODE(&cred->cr_hash);
599         INIT_LIST_HEAD(&cred->cr_lru);
600         refcount_set(&cred->cr_count, 1);
601         cred->cr_auth = auth;
602         cred->cr_flags = 0;
603         cred->cr_ops = ops;
604         cred->cr_expire = jiffies;
605         cred->cr_cred = get_cred(acred->cred);
606 }
607 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
608
609 static struct rpc_cred *
610 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
611 {
612         struct rpc_auth *auth = task->tk_client->cl_auth;
613         struct auth_cred acred = {
614                 .cred = get_task_cred(&init_task),
615         };
616         struct rpc_cred *ret;
617
618         if (RPC_IS_ASYNC(task))
619                 lookupflags |= RPCAUTH_LOOKUP_ASYNC;
620         ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
621         put_cred(acred.cred);
622         return ret;
623 }
624
625 static struct rpc_cred *
626 rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags)
627 {
628         struct rpc_auth *auth = task->tk_client->cl_auth;
629         struct auth_cred acred = {
630                 .principal = task->tk_client->cl_principal,
631                 .cred = init_task.cred,
632         };
633
634         if (!acred.principal)
635                 return NULL;
636         if (RPC_IS_ASYNC(task))
637                 lookupflags |= RPCAUTH_LOOKUP_ASYNC;
638         return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
639 }
640
641 static struct rpc_cred *
642 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
643 {
644         struct rpc_auth *auth = task->tk_client->cl_auth;
645
646         return rpcauth_lookupcred(auth, lookupflags);
647 }
648
649 static int
650 rpcauth_bindcred(struct rpc_task *task, const struct cred *cred, int flags)
651 {
652         struct rpc_rqst *req = task->tk_rqstp;
653         struct rpc_cred *new = NULL;
654         int lookupflags = 0;
655         struct rpc_auth *auth = task->tk_client->cl_auth;
656         struct auth_cred acred = {
657                 .cred = cred,
658         };
659
660         if (flags & RPC_TASK_ASYNC)
661                 lookupflags |= RPCAUTH_LOOKUP_NEW | RPCAUTH_LOOKUP_ASYNC;
662         if (task->tk_op_cred)
663                 /* Task must use exactly this rpc_cred */
664                 new = get_rpccred(task->tk_op_cred);
665         else if (cred != NULL && cred != &machine_cred)
666                 new = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
667         else if (cred == &machine_cred)
668                 new = rpcauth_bind_machine_cred(task, lookupflags);
669
670         /* If machine cred couldn't be bound, try a root cred */
671         if (new)
672                 ;
673         else if (cred == &machine_cred)
674                 new = rpcauth_bind_root_cred(task, lookupflags);
675         else if (flags & RPC_TASK_NULLCREDS)
676                 new = authnull_ops.lookup_cred(NULL, NULL, 0);
677         else
678                 new = rpcauth_bind_new_cred(task, lookupflags);
679         if (IS_ERR(new))
680                 return PTR_ERR(new);
681         put_rpccred(req->rq_cred);
682         req->rq_cred = new;
683         return 0;
684 }
685
686 void
687 put_rpccred(struct rpc_cred *cred)
688 {
689         if (cred == NULL)
690                 return;
691         rcu_read_lock();
692         if (refcount_dec_and_test(&cred->cr_count))
693                 goto destroy;
694         if (refcount_read(&cred->cr_count) != 1 ||
695             !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
696                 goto out;
697         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
698                 cred->cr_expire = jiffies;
699                 rpcauth_lru_add(cred);
700                 /* Race breaker */
701                 if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)))
702                         rpcauth_lru_remove(cred);
703         } else if (rpcauth_unhash_cred(cred)) {
704                 rpcauth_lru_remove(cred);
705                 if (refcount_dec_and_test(&cred->cr_count))
706                         goto destroy;
707         }
708 out:
709         rcu_read_unlock();
710         return;
711 destroy:
712         rcu_read_unlock();
713         cred->cr_ops->crdestroy(cred);
714 }
715 EXPORT_SYMBOL_GPL(put_rpccred);
716
717 /**
718  * rpcauth_marshcred - Append RPC credential to end of @xdr
719  * @task: controlling RPC task
720  * @xdr: xdr_stream containing initial portion of RPC Call header
721  *
722  * On success, an appropriate verifier is added to @xdr, @xdr is
723  * updated to point past the verifier, and zero is returned.
724  * Otherwise, @xdr is in an undefined state and a negative errno
725  * is returned.
726  */
727 int rpcauth_marshcred(struct rpc_task *task, struct xdr_stream *xdr)
728 {
729         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
730
731         return ops->crmarshal(task, xdr);
732 }
733
734 /**
735  * rpcauth_wrap_req_encode - XDR encode the RPC procedure
736  * @task: controlling RPC task
737  * @xdr: stream where on-the-wire bytes are to be marshalled
738  *
739  * On success, @xdr contains the encoded and wrapped message.
740  * Otherwise, @xdr is in an undefined state.
741  */
742 int rpcauth_wrap_req_encode(struct rpc_task *task, struct xdr_stream *xdr)
743 {
744         kxdreproc_t encode = task->tk_msg.rpc_proc->p_encode;
745
746         encode(task->tk_rqstp, xdr, task->tk_msg.rpc_argp);
747         return 0;
748 }
749 EXPORT_SYMBOL_GPL(rpcauth_wrap_req_encode);
750
751 /**
752  * rpcauth_wrap_req - XDR encode and wrap the RPC procedure
753  * @task: controlling RPC task
754  * @xdr: stream where on-the-wire bytes are to be marshalled
755  *
756  * On success, @xdr contains the encoded and wrapped message,
757  * and zero is returned. Otherwise, @xdr is in an undefined
758  * state and a negative errno is returned.
759  */
760 int rpcauth_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
761 {
762         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
763
764         return ops->crwrap_req(task, xdr);
765 }
766
767 /**
768  * rpcauth_checkverf - Validate verifier in RPC Reply header
769  * @task: controlling RPC task
770  * @xdr: xdr_stream containing RPC Reply header
771  *
772  * Return values:
773  *   %0: Verifier is valid. @xdr now points past the verifier.
774  *   %-EIO: Verifier is corrupted or message ended early.
775  *   %-EACCES: Verifier is intact but not valid.
776  *   %-EPROTONOSUPPORT: Server does not support the requested auth type.
777  *
778  * When a negative errno is returned, @xdr is left in an undefined
779  * state.
780  */
781 int
782 rpcauth_checkverf(struct rpc_task *task, struct xdr_stream *xdr)
783 {
784         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
785
786         return ops->crvalidate(task, xdr);
787 }
788
789 /**
790  * rpcauth_unwrap_resp_decode - Invoke XDR decode function
791  * @task: controlling RPC task
792  * @xdr: stream where the Reply message resides
793  *
794  * Returns zero on success; otherwise a negative errno is returned.
795  */
796 int
797 rpcauth_unwrap_resp_decode(struct rpc_task *task, struct xdr_stream *xdr)
798 {
799         kxdrdproc_t decode = task->tk_msg.rpc_proc->p_decode;
800
801         return decode(task->tk_rqstp, xdr, task->tk_msg.rpc_resp);
802 }
803 EXPORT_SYMBOL_GPL(rpcauth_unwrap_resp_decode);
804
805 /**
806  * rpcauth_unwrap_resp - Invoke unwrap and decode function for the cred
807  * @task: controlling RPC task
808  * @xdr: stream where the Reply message resides
809  *
810  * Returns zero on success; otherwise a negative errno is returned.
811  */
812 int
813 rpcauth_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr)
814 {
815         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
816
817         return ops->crunwrap_resp(task, xdr);
818 }
819
820 bool
821 rpcauth_xmit_need_reencode(struct rpc_task *task)
822 {
823         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
824
825         if (!cred || !cred->cr_ops->crneed_reencode)
826                 return false;
827         return cred->cr_ops->crneed_reencode(task);
828 }
829
830 int
831 rpcauth_refreshcred(struct rpc_task *task)
832 {
833         struct rpc_cred *cred;
834         int err;
835
836         cred = task->tk_rqstp->rq_cred;
837         if (cred == NULL) {
838                 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
839                 if (err < 0)
840                         goto out;
841                 cred = task->tk_rqstp->rq_cred;
842         }
843
844         err = cred->cr_ops->crrefresh(task);
845 out:
846         if (err < 0)
847                 task->tk_status = err;
848         return err;
849 }
850
851 void
852 rpcauth_invalcred(struct rpc_task *task)
853 {
854         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
855
856         if (cred)
857                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
858 }
859
860 int
861 rpcauth_uptodatecred(struct rpc_task *task)
862 {
863         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
864
865         return cred == NULL ||
866                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
867 }
868
869 static struct shrinker rpc_cred_shrinker = {
870         .count_objects = rpcauth_cache_shrink_count,
871         .scan_objects = rpcauth_cache_shrink_scan,
872         .seeks = DEFAULT_SEEKS,
873 };
874
875 int __init rpcauth_init_module(void)
876 {
877         int err;
878
879         err = rpc_init_authunix();
880         if (err < 0)
881                 goto out1;
882         err = register_shrinker(&rpc_cred_shrinker, "sunrpc_cred");
883         if (err < 0)
884                 goto out2;
885         return 0;
886 out2:
887         rpc_destroy_authunix();
888 out1:
889         return err;
890 }
891
892 void rpcauth_remove_module(void)
893 {
894         rpc_destroy_authunix();
895         unregister_shrinker(&rpc_cred_shrinker);
896 }