Merge branch 'for-2.6.37' of git://linux-nfs.org/~bfields/linux
[~shefty/rdma-dev.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/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/spinlock.h>
17
18 #ifdef RPC_DEBUG
19 # define RPCDBG_FACILITY        RPCDBG_AUTH
20 #endif
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 DEFINE_SPINLOCK(rpc_authflavor_lock);
32 static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
33         &authnull_ops,          /* AUTH_NULL */
34         &authunix_ops,          /* AUTH_UNIX */
35         NULL,                   /* others can be loadable modules */
36 };
37
38 static LIST_HEAD(cred_unused);
39 static unsigned long number_cred_unused;
40
41 #define MAX_HASHTABLE_BITS (14)
42 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
43 {
44         unsigned long num;
45         unsigned int nbits;
46         int ret;
47
48         if (!val)
49                 goto out_inval;
50         ret = strict_strtoul(val, 0, &num);
51         if (ret == -EINVAL)
52                 goto out_inval;
53         nbits = fls(num);
54         if (num > (1U << nbits))
55                 nbits++;
56         if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
57                 goto out_inval;
58         *(unsigned int *)kp->arg = nbits;
59         return 0;
60 out_inval:
61         return -EINVAL;
62 }
63
64 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
65 {
66         unsigned int nbits;
67
68         nbits = *(unsigned int *)kp->arg;
69         return sprintf(buffer, "%u", 1U << nbits);
70 }
71
72 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
73
74 static struct kernel_param_ops param_ops_hashtbl_sz = {
75         .set = param_set_hashtbl_sz,
76         .get = param_get_hashtbl_sz,
77 };
78
79 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
80 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
81
82 static u32
83 pseudoflavor_to_flavor(u32 flavor) {
84         if (flavor >= RPC_AUTH_MAXFLAVOR)
85                 return RPC_AUTH_GSS;
86         return flavor;
87 }
88
89 int
90 rpcauth_register(const struct rpc_authops *ops)
91 {
92         rpc_authflavor_t flavor;
93         int ret = -EPERM;
94
95         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
96                 return -EINVAL;
97         spin_lock(&rpc_authflavor_lock);
98         if (auth_flavors[flavor] == NULL) {
99                 auth_flavors[flavor] = ops;
100                 ret = 0;
101         }
102         spin_unlock(&rpc_authflavor_lock);
103         return ret;
104 }
105 EXPORT_SYMBOL_GPL(rpcauth_register);
106
107 int
108 rpcauth_unregister(const struct rpc_authops *ops)
109 {
110         rpc_authflavor_t flavor;
111         int ret = -EPERM;
112
113         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
114                 return -EINVAL;
115         spin_lock(&rpc_authflavor_lock);
116         if (auth_flavors[flavor] == ops) {
117                 auth_flavors[flavor] = NULL;
118                 ret = 0;
119         }
120         spin_unlock(&rpc_authflavor_lock);
121         return ret;
122 }
123 EXPORT_SYMBOL_GPL(rpcauth_unregister);
124
125 struct rpc_auth *
126 rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
127 {
128         struct rpc_auth         *auth;
129         const struct rpc_authops *ops;
130         u32                     flavor = pseudoflavor_to_flavor(pseudoflavor);
131
132         auth = ERR_PTR(-EINVAL);
133         if (flavor >= RPC_AUTH_MAXFLAVOR)
134                 goto out;
135
136         if ((ops = auth_flavors[flavor]) == NULL)
137                 request_module("rpc-auth-%u", flavor);
138         spin_lock(&rpc_authflavor_lock);
139         ops = auth_flavors[flavor];
140         if (ops == NULL || !try_module_get(ops->owner)) {
141                 spin_unlock(&rpc_authflavor_lock);
142                 goto out;
143         }
144         spin_unlock(&rpc_authflavor_lock);
145         auth = ops->create(clnt, pseudoflavor);
146         module_put(ops->owner);
147         if (IS_ERR(auth))
148                 return auth;
149         if (clnt->cl_auth)
150                 rpcauth_release(clnt->cl_auth);
151         clnt->cl_auth = auth;
152
153 out:
154         return auth;
155 }
156 EXPORT_SYMBOL_GPL(rpcauth_create);
157
158 void
159 rpcauth_release(struct rpc_auth *auth)
160 {
161         if (!atomic_dec_and_test(&auth->au_count))
162                 return;
163         auth->au_ops->destroy(auth);
164 }
165
166 static DEFINE_SPINLOCK(rpc_credcache_lock);
167
168 static void
169 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
170 {
171         hlist_del_rcu(&cred->cr_hash);
172         smp_mb__before_clear_bit();
173         clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
174 }
175
176 static int
177 rpcauth_unhash_cred(struct rpc_cred *cred)
178 {
179         spinlock_t *cache_lock;
180         int ret;
181
182         cache_lock = &cred->cr_auth->au_credcache->lock;
183         spin_lock(cache_lock);
184         ret = atomic_read(&cred->cr_count) == 0;
185         if (ret)
186                 rpcauth_unhash_cred_locked(cred);
187         spin_unlock(cache_lock);
188         return ret;
189 }
190
191 /*
192  * Initialize RPC credential cache
193  */
194 int
195 rpcauth_init_credcache(struct rpc_auth *auth)
196 {
197         struct rpc_cred_cache *new;
198         unsigned int hashsize;
199
200         new = kmalloc(sizeof(*new), GFP_KERNEL);
201         if (!new)
202                 goto out_nocache;
203         new->hashbits = auth_hashbits;
204         hashsize = 1U << new->hashbits;
205         new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
206         if (!new->hashtable)
207                 goto out_nohashtbl;
208         spin_lock_init(&new->lock);
209         auth->au_credcache = new;
210         return 0;
211 out_nohashtbl:
212         kfree(new);
213 out_nocache:
214         return -ENOMEM;
215 }
216 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
217
218 /*
219  * Destroy a list of credentials
220  */
221 static inline
222 void rpcauth_destroy_credlist(struct list_head *head)
223 {
224         struct rpc_cred *cred;
225
226         while (!list_empty(head)) {
227                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
228                 list_del_init(&cred->cr_lru);
229                 put_rpccred(cred);
230         }
231 }
232
233 /*
234  * Clear the RPC credential cache, and delete those credentials
235  * that are not referenced.
236  */
237 void
238 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
239 {
240         LIST_HEAD(free);
241         struct hlist_head *head;
242         struct rpc_cred *cred;
243         unsigned int hashsize = 1U << cache->hashbits;
244         int             i;
245
246         spin_lock(&rpc_credcache_lock);
247         spin_lock(&cache->lock);
248         for (i = 0; i < hashsize; i++) {
249                 head = &cache->hashtable[i];
250                 while (!hlist_empty(head)) {
251                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
252                         get_rpccred(cred);
253                         if (!list_empty(&cred->cr_lru)) {
254                                 list_del(&cred->cr_lru);
255                                 number_cred_unused--;
256                         }
257                         list_add_tail(&cred->cr_lru, &free);
258                         rpcauth_unhash_cred_locked(cred);
259                 }
260         }
261         spin_unlock(&cache->lock);
262         spin_unlock(&rpc_credcache_lock);
263         rpcauth_destroy_credlist(&free);
264 }
265
266 /*
267  * Destroy the RPC credential cache
268  */
269 void
270 rpcauth_destroy_credcache(struct rpc_auth *auth)
271 {
272         struct rpc_cred_cache *cache = auth->au_credcache;
273
274         if (cache) {
275                 auth->au_credcache = NULL;
276                 rpcauth_clear_credcache(cache);
277                 kfree(cache->hashtable);
278                 kfree(cache);
279         }
280 }
281 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
282
283
284 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
285
286 /*
287  * Remove stale credentials. Avoid sleeping inside the loop.
288  */
289 static int
290 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
291 {
292         spinlock_t *cache_lock;
293         struct rpc_cred *cred, *next;
294         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
295
296         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
297
298                 if (nr_to_scan-- == 0)
299                         break;
300                 /*
301                  * Enforce a 60 second garbage collection moratorium
302                  * Note that the cred_unused list must be time-ordered.
303                  */
304                 if (time_in_range(cred->cr_expire, expired, jiffies) &&
305                     test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
306                         return 0;
307
308                 list_del_init(&cred->cr_lru);
309                 number_cred_unused--;
310                 if (atomic_read(&cred->cr_count) != 0)
311                         continue;
312
313                 cache_lock = &cred->cr_auth->au_credcache->lock;
314                 spin_lock(cache_lock);
315                 if (atomic_read(&cred->cr_count) == 0) {
316                         get_rpccred(cred);
317                         list_add_tail(&cred->cr_lru, free);
318                         rpcauth_unhash_cred_locked(cred);
319                 }
320                 spin_unlock(cache_lock);
321         }
322         return (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
323 }
324
325 /*
326  * Run memory cache shrinker.
327  */
328 static int
329 rpcauth_cache_shrinker(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
330 {
331         LIST_HEAD(free);
332         int res;
333
334         if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
335                 return (nr_to_scan == 0) ? 0 : -1;
336         if (list_empty(&cred_unused))
337                 return 0;
338         spin_lock(&rpc_credcache_lock);
339         res = rpcauth_prune_expired(&free, nr_to_scan);
340         spin_unlock(&rpc_credcache_lock);
341         rpcauth_destroy_credlist(&free);
342         return res;
343 }
344
345 /*
346  * Look up a process' credentials in the authentication cache
347  */
348 struct rpc_cred *
349 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
350                 int flags)
351 {
352         LIST_HEAD(free);
353         struct rpc_cred_cache *cache = auth->au_credcache;
354         struct hlist_node *pos;
355         struct rpc_cred *cred = NULL,
356                         *entry, *new;
357         unsigned int nr;
358
359         nr = hash_long(acred->uid, cache->hashbits);
360
361         rcu_read_lock();
362         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
363                 if (!entry->cr_ops->crmatch(acred, entry, flags))
364                         continue;
365                 spin_lock(&cache->lock);
366                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
367                         spin_unlock(&cache->lock);
368                         continue;
369                 }
370                 cred = get_rpccred(entry);
371                 spin_unlock(&cache->lock);
372                 break;
373         }
374         rcu_read_unlock();
375
376         if (cred != NULL)
377                 goto found;
378
379         new = auth->au_ops->crcreate(auth, acred, flags);
380         if (IS_ERR(new)) {
381                 cred = new;
382                 goto out;
383         }
384
385         spin_lock(&cache->lock);
386         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
387                 if (!entry->cr_ops->crmatch(acred, entry, flags))
388                         continue;
389                 cred = get_rpccred(entry);
390                 break;
391         }
392         if (cred == NULL) {
393                 cred = new;
394                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
395                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
396         } else
397                 list_add_tail(&new->cr_lru, &free);
398         spin_unlock(&cache->lock);
399 found:
400         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
401             cred->cr_ops->cr_init != NULL &&
402             !(flags & RPCAUTH_LOOKUP_NEW)) {
403                 int res = cred->cr_ops->cr_init(auth, cred);
404                 if (res < 0) {
405                         put_rpccred(cred);
406                         cred = ERR_PTR(res);
407                 }
408         }
409         rpcauth_destroy_credlist(&free);
410 out:
411         return cred;
412 }
413 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
414
415 struct rpc_cred *
416 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
417 {
418         struct auth_cred acred;
419         struct rpc_cred *ret;
420         const struct cred *cred = current_cred();
421
422         dprintk("RPC:       looking up %s cred\n",
423                 auth->au_ops->au_name);
424
425         memset(&acred, 0, sizeof(acred));
426         acred.uid = cred->fsuid;
427         acred.gid = cred->fsgid;
428         acred.group_info = get_group_info(((struct cred *)cred)->group_info);
429
430         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
431         put_group_info(acred.group_info);
432         return ret;
433 }
434
435 void
436 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
437                   struct rpc_auth *auth, const struct rpc_credops *ops)
438 {
439         INIT_HLIST_NODE(&cred->cr_hash);
440         INIT_LIST_HEAD(&cred->cr_lru);
441         atomic_set(&cred->cr_count, 1);
442         cred->cr_auth = auth;
443         cred->cr_ops = ops;
444         cred->cr_expire = jiffies;
445 #ifdef RPC_DEBUG
446         cred->cr_magic = RPCAUTH_CRED_MAGIC;
447 #endif
448         cred->cr_uid = acred->uid;
449 }
450 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
451
452 struct rpc_cred *
453 rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags)
454 {
455         dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
456                         cred->cr_auth->au_ops->au_name, cred);
457         return get_rpccred(cred);
458 }
459 EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
460
461 static struct rpc_cred *
462 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
463 {
464         struct rpc_auth *auth = task->tk_client->cl_auth;
465         struct auth_cred acred = {
466                 .uid = 0,
467                 .gid = 0,
468         };
469
470         dprintk("RPC: %5u looking up %s cred\n",
471                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
472         return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
473 }
474
475 static struct rpc_cred *
476 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
477 {
478         struct rpc_auth *auth = task->tk_client->cl_auth;
479
480         dprintk("RPC: %5u looking up %s cred\n",
481                 task->tk_pid, auth->au_ops->au_name);
482         return rpcauth_lookupcred(auth, lookupflags);
483 }
484
485 static int
486 rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
487 {
488         struct rpc_rqst *req = task->tk_rqstp;
489         struct rpc_cred *new;
490         int lookupflags = 0;
491
492         if (flags & RPC_TASK_ASYNC)
493                 lookupflags |= RPCAUTH_LOOKUP_NEW;
494         if (cred != NULL)
495                 new = cred->cr_ops->crbind(task, cred, lookupflags);
496         else if (flags & RPC_TASK_ROOTCREDS)
497                 new = rpcauth_bind_root_cred(task, lookupflags);
498         else
499                 new = rpcauth_bind_new_cred(task, lookupflags);
500         if (IS_ERR(new))
501                 return PTR_ERR(new);
502         if (req->rq_cred != NULL)
503                 put_rpccred(req->rq_cred);
504         req->rq_cred = new;
505         return 0;
506 }
507
508 void
509 put_rpccred(struct rpc_cred *cred)
510 {
511         /* Fast path for unhashed credentials */
512         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) {
513                 if (atomic_dec_and_test(&cred->cr_count))
514                         cred->cr_ops->crdestroy(cred);
515                 return;
516         }
517
518         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
519                 return;
520         if (!list_empty(&cred->cr_lru)) {
521                 number_cred_unused--;
522                 list_del_init(&cred->cr_lru);
523         }
524         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
525                 if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
526                         cred->cr_expire = jiffies;
527                         list_add_tail(&cred->cr_lru, &cred_unused);
528                         number_cred_unused++;
529                         goto out_nodestroy;
530                 }
531                 if (!rpcauth_unhash_cred(cred)) {
532                         /* We were hashed and someone looked us up... */
533                         goto out_nodestroy;
534                 }
535         }
536         spin_unlock(&rpc_credcache_lock);
537         cred->cr_ops->crdestroy(cred);
538         return;
539 out_nodestroy:
540         spin_unlock(&rpc_credcache_lock);
541 }
542 EXPORT_SYMBOL_GPL(put_rpccred);
543
544 __be32 *
545 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
546 {
547         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
548
549         dprintk("RPC: %5u marshaling %s cred %p\n",
550                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
551
552         return cred->cr_ops->crmarshal(task, p);
553 }
554
555 __be32 *
556 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
557 {
558         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
559
560         dprintk("RPC: %5u validating %s cred %p\n",
561                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
562
563         return cred->cr_ops->crvalidate(task, p);
564 }
565
566 int
567 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
568                 __be32 *data, void *obj)
569 {
570         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
571
572         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
573                         task->tk_pid, cred->cr_ops->cr_name, cred);
574         if (cred->cr_ops->crwrap_req)
575                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
576         /* By default, we encode the arguments normally. */
577         return encode(rqstp, data, obj);
578 }
579
580 int
581 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
582                 __be32 *data, void *obj)
583 {
584         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
585
586         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
587                         task->tk_pid, cred->cr_ops->cr_name, cred);
588         if (cred->cr_ops->crunwrap_resp)
589                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
590                                                    data, obj);
591         /* By default, we decode the arguments normally. */
592         return decode(rqstp, data, obj);
593 }
594
595 int
596 rpcauth_refreshcred(struct rpc_task *task)
597 {
598         struct rpc_cred *cred;
599         int err;
600
601         cred = task->tk_rqstp->rq_cred;
602         if (cred == NULL) {
603                 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
604                 if (err < 0)
605                         goto out;
606                 cred = task->tk_rqstp->rq_cred;
607         };
608         dprintk("RPC: %5u refreshing %s cred %p\n",
609                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
610
611         err = cred->cr_ops->crrefresh(task);
612 out:
613         if (err < 0)
614                 task->tk_status = err;
615         return err;
616 }
617
618 void
619 rpcauth_invalcred(struct rpc_task *task)
620 {
621         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
622
623         dprintk("RPC: %5u invalidating %s cred %p\n",
624                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
625         if (cred)
626                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
627 }
628
629 int
630 rpcauth_uptodatecred(struct rpc_task *task)
631 {
632         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
633
634         return cred == NULL ||
635                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
636 }
637
638 static struct shrinker rpc_cred_shrinker = {
639         .shrink = rpcauth_cache_shrinker,
640         .seeks = DEFAULT_SEEKS,
641 };
642
643 int __init rpcauth_init_module(void)
644 {
645         int err;
646
647         err = rpc_init_authunix();
648         if (err < 0)
649                 goto out1;
650         err = rpc_init_generic_auth();
651         if (err < 0)
652                 goto out2;
653         register_shrinker(&rpc_cred_shrinker);
654         return 0;
655 out2:
656         rpc_destroy_authunix();
657 out1:
658         return err;
659 }
660
661 void rpcauth_remove_module(void)
662 {
663         rpc_destroy_authunix();
664         rpc_destroy_generic_auth();
665         unregister_shrinker(&rpc_cred_shrinker);
666 }