SUNRPC: Store the hashtable size in struct rpc_cred_cache
[linux-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/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 static DEFINE_SPINLOCK(rpc_authflavor_lock);
23 static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
24         &authnull_ops,          /* AUTH_NULL */
25         &authunix_ops,          /* AUTH_UNIX */
26         NULL,                   /* others can be loadable modules */
27 };
28
29 static LIST_HEAD(cred_unused);
30 static unsigned long number_cred_unused;
31
32 static u32
33 pseudoflavor_to_flavor(u32 flavor) {
34         if (flavor >= RPC_AUTH_MAXFLAVOR)
35                 return RPC_AUTH_GSS;
36         return flavor;
37 }
38
39 int
40 rpcauth_register(const struct rpc_authops *ops)
41 {
42         rpc_authflavor_t flavor;
43         int ret = -EPERM;
44
45         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
46                 return -EINVAL;
47         spin_lock(&rpc_authflavor_lock);
48         if (auth_flavors[flavor] == NULL) {
49                 auth_flavors[flavor] = ops;
50                 ret = 0;
51         }
52         spin_unlock(&rpc_authflavor_lock);
53         return ret;
54 }
55 EXPORT_SYMBOL_GPL(rpcauth_register);
56
57 int
58 rpcauth_unregister(const struct rpc_authops *ops)
59 {
60         rpc_authflavor_t flavor;
61         int ret = -EPERM;
62
63         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
64                 return -EINVAL;
65         spin_lock(&rpc_authflavor_lock);
66         if (auth_flavors[flavor] == ops) {
67                 auth_flavors[flavor] = NULL;
68                 ret = 0;
69         }
70         spin_unlock(&rpc_authflavor_lock);
71         return ret;
72 }
73 EXPORT_SYMBOL_GPL(rpcauth_unregister);
74
75 struct rpc_auth *
76 rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
77 {
78         struct rpc_auth         *auth;
79         const struct rpc_authops *ops;
80         u32                     flavor = pseudoflavor_to_flavor(pseudoflavor);
81
82         auth = ERR_PTR(-EINVAL);
83         if (flavor >= RPC_AUTH_MAXFLAVOR)
84                 goto out;
85
86         if ((ops = auth_flavors[flavor]) == NULL)
87                 request_module("rpc-auth-%u", flavor);
88         spin_lock(&rpc_authflavor_lock);
89         ops = auth_flavors[flavor];
90         if (ops == NULL || !try_module_get(ops->owner)) {
91                 spin_unlock(&rpc_authflavor_lock);
92                 goto out;
93         }
94         spin_unlock(&rpc_authflavor_lock);
95         auth = ops->create(clnt, pseudoflavor);
96         module_put(ops->owner);
97         if (IS_ERR(auth))
98                 return auth;
99         if (clnt->cl_auth)
100                 rpcauth_release(clnt->cl_auth);
101         clnt->cl_auth = auth;
102
103 out:
104         return auth;
105 }
106 EXPORT_SYMBOL_GPL(rpcauth_create);
107
108 void
109 rpcauth_release(struct rpc_auth *auth)
110 {
111         if (!atomic_dec_and_test(&auth->au_count))
112                 return;
113         auth->au_ops->destroy(auth);
114 }
115
116 static DEFINE_SPINLOCK(rpc_credcache_lock);
117
118 static void
119 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
120 {
121         hlist_del_rcu(&cred->cr_hash);
122         smp_mb__before_clear_bit();
123         clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
124 }
125
126 static int
127 rpcauth_unhash_cred(struct rpc_cred *cred)
128 {
129         spinlock_t *cache_lock;
130         int ret;
131
132         cache_lock = &cred->cr_auth->au_credcache->lock;
133         spin_lock(cache_lock);
134         ret = atomic_read(&cred->cr_count) == 0;
135         if (ret)
136                 rpcauth_unhash_cred_locked(cred);
137         spin_unlock(cache_lock);
138         return ret;
139 }
140
141 /*
142  * Initialize RPC credential cache
143  */
144 int
145 rpcauth_init_credcache(struct rpc_auth *auth)
146 {
147         struct rpc_cred_cache *new;
148         unsigned int hashsize;
149         int i;
150
151         new = kmalloc(sizeof(*new), GFP_KERNEL);
152         if (!new)
153                 return -ENOMEM;
154         new->hashbits = RPC_CREDCACHE_HASHBITS;
155         hashsize = 1U << new->hashbits;
156         for (i = 0; i < hashsize; i++)
157                 INIT_HLIST_HEAD(&new->hashtable[i]);
158         spin_lock_init(&new->lock);
159         auth->au_credcache = new;
160         return 0;
161 }
162 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
163
164 /*
165  * Destroy a list of credentials
166  */
167 static inline
168 void rpcauth_destroy_credlist(struct list_head *head)
169 {
170         struct rpc_cred *cred;
171
172         while (!list_empty(head)) {
173                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
174                 list_del_init(&cred->cr_lru);
175                 put_rpccred(cred);
176         }
177 }
178
179 /*
180  * Clear the RPC credential cache, and delete those credentials
181  * that are not referenced.
182  */
183 void
184 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
185 {
186         LIST_HEAD(free);
187         struct hlist_head *head;
188         struct rpc_cred *cred;
189         unsigned int hashsize = 1U << cache->hashbits;
190         int             i;
191
192         spin_lock(&rpc_credcache_lock);
193         spin_lock(&cache->lock);
194         for (i = 0; i < hashsize; i++) {
195                 head = &cache->hashtable[i];
196                 while (!hlist_empty(head)) {
197                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
198                         get_rpccred(cred);
199                         if (!list_empty(&cred->cr_lru)) {
200                                 list_del(&cred->cr_lru);
201                                 number_cred_unused--;
202                         }
203                         list_add_tail(&cred->cr_lru, &free);
204                         rpcauth_unhash_cred_locked(cred);
205                 }
206         }
207         spin_unlock(&cache->lock);
208         spin_unlock(&rpc_credcache_lock);
209         rpcauth_destroy_credlist(&free);
210 }
211
212 /*
213  * Destroy the RPC credential cache
214  */
215 void
216 rpcauth_destroy_credcache(struct rpc_auth *auth)
217 {
218         struct rpc_cred_cache *cache = auth->au_credcache;
219
220         if (cache) {
221                 auth->au_credcache = NULL;
222                 rpcauth_clear_credcache(cache);
223                 kfree(cache);
224         }
225 }
226 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
227
228
229 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
230
231 /*
232  * Remove stale credentials. Avoid sleeping inside the loop.
233  */
234 static int
235 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
236 {
237         spinlock_t *cache_lock;
238         struct rpc_cred *cred, *next;
239         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
240
241         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
242
243                 if (nr_to_scan-- == 0)
244                         break;
245                 /*
246                  * Enforce a 60 second garbage collection moratorium
247                  * Note that the cred_unused list must be time-ordered.
248                  */
249                 if (time_in_range(cred->cr_expire, expired, jiffies) &&
250                     test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
251                         return 0;
252
253                 list_del_init(&cred->cr_lru);
254                 number_cred_unused--;
255                 if (atomic_read(&cred->cr_count) != 0)
256                         continue;
257
258                 cache_lock = &cred->cr_auth->au_credcache->lock;
259                 spin_lock(cache_lock);
260                 if (atomic_read(&cred->cr_count) == 0) {
261                         get_rpccred(cred);
262                         list_add_tail(&cred->cr_lru, free);
263                         rpcauth_unhash_cred_locked(cred);
264                 }
265                 spin_unlock(cache_lock);
266         }
267         return (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
268 }
269
270 /*
271  * Run memory cache shrinker.
272  */
273 static int
274 rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
275 {
276         LIST_HEAD(free);
277         int res;
278
279         if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
280                 return (nr_to_scan == 0) ? 0 : -1;
281         if (list_empty(&cred_unused))
282                 return 0;
283         spin_lock(&rpc_credcache_lock);
284         res = rpcauth_prune_expired(&free, nr_to_scan);
285         spin_unlock(&rpc_credcache_lock);
286         rpcauth_destroy_credlist(&free);
287         return res;
288 }
289
290 /*
291  * Look up a process' credentials in the authentication cache
292  */
293 struct rpc_cred *
294 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
295                 int flags)
296 {
297         LIST_HEAD(free);
298         struct rpc_cred_cache *cache = auth->au_credcache;
299         struct hlist_node *pos;
300         struct rpc_cred *cred = NULL,
301                         *entry, *new;
302         unsigned int nr;
303
304         nr = hash_long(acred->uid, cache->hashbits);
305
306         rcu_read_lock();
307         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
308                 if (!entry->cr_ops->crmatch(acred, entry, flags))
309                         continue;
310                 spin_lock(&cache->lock);
311                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
312                         spin_unlock(&cache->lock);
313                         continue;
314                 }
315                 cred = get_rpccred(entry);
316                 spin_unlock(&cache->lock);
317                 break;
318         }
319         rcu_read_unlock();
320
321         if (cred != NULL)
322                 goto found;
323
324         new = auth->au_ops->crcreate(auth, acred, flags);
325         if (IS_ERR(new)) {
326                 cred = new;
327                 goto out;
328         }
329
330         spin_lock(&cache->lock);
331         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
332                 if (!entry->cr_ops->crmatch(acred, entry, flags))
333                         continue;
334                 cred = get_rpccred(entry);
335                 break;
336         }
337         if (cred == NULL) {
338                 cred = new;
339                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
340                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
341         } else
342                 list_add_tail(&new->cr_lru, &free);
343         spin_unlock(&cache->lock);
344 found:
345         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
346             cred->cr_ops->cr_init != NULL &&
347             !(flags & RPCAUTH_LOOKUP_NEW)) {
348                 int res = cred->cr_ops->cr_init(auth, cred);
349                 if (res < 0) {
350                         put_rpccred(cred);
351                         cred = ERR_PTR(res);
352                 }
353         }
354         rpcauth_destroy_credlist(&free);
355 out:
356         return cred;
357 }
358 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
359
360 struct rpc_cred *
361 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
362 {
363         struct auth_cred acred;
364         struct rpc_cred *ret;
365         const struct cred *cred = current_cred();
366
367         dprintk("RPC:       looking up %s cred\n",
368                 auth->au_ops->au_name);
369
370         memset(&acred, 0, sizeof(acred));
371         acred.uid = cred->fsuid;
372         acred.gid = cred->fsgid;
373         acred.group_info = get_group_info(((struct cred *)cred)->group_info);
374
375         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
376         put_group_info(acred.group_info);
377         return ret;
378 }
379
380 void
381 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
382                   struct rpc_auth *auth, const struct rpc_credops *ops)
383 {
384         INIT_HLIST_NODE(&cred->cr_hash);
385         INIT_LIST_HEAD(&cred->cr_lru);
386         atomic_set(&cred->cr_count, 1);
387         cred->cr_auth = auth;
388         cred->cr_ops = ops;
389         cred->cr_expire = jiffies;
390 #ifdef RPC_DEBUG
391         cred->cr_magic = RPCAUTH_CRED_MAGIC;
392 #endif
393         cred->cr_uid = acred->uid;
394 }
395 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
396
397 void
398 rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags)
399 {
400         task->tk_msg.rpc_cred = get_rpccred(cred);
401         dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
402                         cred->cr_auth->au_ops->au_name, cred);
403 }
404 EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
405
406 static void
407 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
408 {
409         struct rpc_auth *auth = task->tk_client->cl_auth;
410         struct auth_cred acred = {
411                 .uid = 0,
412                 .gid = 0,
413         };
414         struct rpc_cred *ret;
415
416         dprintk("RPC: %5u looking up %s cred\n",
417                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
418         ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
419         if (!IS_ERR(ret))
420                 task->tk_msg.rpc_cred = ret;
421         else
422                 task->tk_status = PTR_ERR(ret);
423 }
424
425 static void
426 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
427 {
428         struct rpc_auth *auth = task->tk_client->cl_auth;
429         struct rpc_cred *ret;
430
431         dprintk("RPC: %5u looking up %s cred\n",
432                 task->tk_pid, auth->au_ops->au_name);
433         ret = rpcauth_lookupcred(auth, lookupflags);
434         if (!IS_ERR(ret))
435                 task->tk_msg.rpc_cred = ret;
436         else
437                 task->tk_status = PTR_ERR(ret);
438 }
439
440 void
441 rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
442 {
443         int lookupflags = 0;
444
445         if (flags & RPC_TASK_ASYNC)
446                 lookupflags |= RPCAUTH_LOOKUP_NEW;
447         if (cred != NULL)
448                 cred->cr_ops->crbind(task, cred, lookupflags);
449         else if (flags & RPC_TASK_ROOTCREDS)
450                 rpcauth_bind_root_cred(task, lookupflags);
451         else
452                 rpcauth_bind_new_cred(task, lookupflags);
453 }
454
455 void
456 put_rpccred(struct rpc_cred *cred)
457 {
458         /* Fast path for unhashed credentials */
459         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) {
460                 if (atomic_dec_and_test(&cred->cr_count))
461                         cred->cr_ops->crdestroy(cred);
462                 return;
463         }
464
465         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
466                 return;
467         if (!list_empty(&cred->cr_lru)) {
468                 number_cred_unused--;
469                 list_del_init(&cred->cr_lru);
470         }
471         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
472                 if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
473                         cred->cr_expire = jiffies;
474                         list_add_tail(&cred->cr_lru, &cred_unused);
475                         number_cred_unused++;
476                         goto out_nodestroy;
477                 }
478                 if (!rpcauth_unhash_cred(cred)) {
479                         /* We were hashed and someone looked us up... */
480                         goto out_nodestroy;
481                 }
482         }
483         spin_unlock(&rpc_credcache_lock);
484         cred->cr_ops->crdestroy(cred);
485         return;
486 out_nodestroy:
487         spin_unlock(&rpc_credcache_lock);
488 }
489 EXPORT_SYMBOL_GPL(put_rpccred);
490
491 void
492 rpcauth_unbindcred(struct rpc_task *task)
493 {
494         struct rpc_cred *cred = task->tk_msg.rpc_cred;
495
496         dprintk("RPC: %5u releasing %s cred %p\n",
497                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
498
499         put_rpccred(cred);
500         task->tk_msg.rpc_cred = NULL;
501 }
502
503 __be32 *
504 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
505 {
506         struct rpc_cred *cred = task->tk_msg.rpc_cred;
507
508         dprintk("RPC: %5u marshaling %s cred %p\n",
509                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
510
511         return cred->cr_ops->crmarshal(task, p);
512 }
513
514 __be32 *
515 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
516 {
517         struct rpc_cred *cred = task->tk_msg.rpc_cred;
518
519         dprintk("RPC: %5u validating %s cred %p\n",
520                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
521
522         return cred->cr_ops->crvalidate(task, p);
523 }
524
525 int
526 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
527                 __be32 *data, void *obj)
528 {
529         struct rpc_cred *cred = task->tk_msg.rpc_cred;
530
531         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
532                         task->tk_pid, cred->cr_ops->cr_name, cred);
533         if (cred->cr_ops->crwrap_req)
534                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
535         /* By default, we encode the arguments normally. */
536         return encode(rqstp, data, obj);
537 }
538
539 int
540 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
541                 __be32 *data, void *obj)
542 {
543         struct rpc_cred *cred = task->tk_msg.rpc_cred;
544
545         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
546                         task->tk_pid, cred->cr_ops->cr_name, cred);
547         if (cred->cr_ops->crunwrap_resp)
548                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
549                                                    data, obj);
550         /* By default, we decode the arguments normally. */
551         return decode(rqstp, data, obj);
552 }
553
554 int
555 rpcauth_refreshcred(struct rpc_task *task)
556 {
557         struct rpc_cred *cred = task->tk_msg.rpc_cred;
558         int err;
559
560         dprintk("RPC: %5u refreshing %s cred %p\n",
561                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
562
563         err = cred->cr_ops->crrefresh(task);
564         if (err < 0)
565                 task->tk_status = err;
566         return err;
567 }
568
569 void
570 rpcauth_invalcred(struct rpc_task *task)
571 {
572         struct rpc_cred *cred = task->tk_msg.rpc_cred;
573
574         dprintk("RPC: %5u invalidating %s cred %p\n",
575                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
576         if (cred)
577                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
578 }
579
580 int
581 rpcauth_uptodatecred(struct rpc_task *task)
582 {
583         struct rpc_cred *cred = task->tk_msg.rpc_cred;
584
585         return cred == NULL ||
586                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
587 }
588
589 static struct shrinker rpc_cred_shrinker = {
590         .shrink = rpcauth_cache_shrinker,
591         .seeks = DEFAULT_SEEKS,
592 };
593
594 int __init rpcauth_init_module(void)
595 {
596         int err;
597
598         err = rpc_init_authunix();
599         if (err < 0)
600                 goto out1;
601         err = rpc_init_generic_auth();
602         if (err < 0)
603                 goto out2;
604         register_shrinker(&rpc_cred_shrinker);
605         return 0;
606 out2:
607         rpc_destroy_authunix();
608 out1:
609         return err;
610 }
611
612 void __exit rpcauth_remove_module(void)
613 {
614         rpc_destroy_authunix();
615         rpc_destroy_generic_auth();
616         unregister_shrinker(&rpc_cred_shrinker);
617 }