6bfea9ed6869f4142d356b468a70493817b233b7
[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 #ifdef CONFIG_KMOD
87         if ((ops = auth_flavors[flavor]) == NULL)
88                 request_module("rpc-auth-%u", flavor);
89 #endif
90         spin_lock(&rpc_authflavor_lock);
91         ops = auth_flavors[flavor];
92         if (ops == NULL || !try_module_get(ops->owner)) {
93                 spin_unlock(&rpc_authflavor_lock);
94                 goto out;
95         }
96         spin_unlock(&rpc_authflavor_lock);
97         auth = ops->create(clnt, pseudoflavor);
98         module_put(ops->owner);
99         if (IS_ERR(auth))
100                 return auth;
101         if (clnt->cl_auth)
102                 rpcauth_release(clnt->cl_auth);
103         clnt->cl_auth = auth;
104
105 out:
106         return auth;
107 }
108 EXPORT_SYMBOL_GPL(rpcauth_create);
109
110 void
111 rpcauth_release(struct rpc_auth *auth)
112 {
113         if (!atomic_dec_and_test(&auth->au_count))
114                 return;
115         auth->au_ops->destroy(auth);
116 }
117
118 static DEFINE_SPINLOCK(rpc_credcache_lock);
119
120 static void
121 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
122 {
123         hlist_del_rcu(&cred->cr_hash);
124         smp_mb__before_clear_bit();
125         clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
126 }
127
128 static void
129 rpcauth_unhash_cred(struct rpc_cred *cred)
130 {
131         spinlock_t *cache_lock;
132
133         cache_lock = &cred->cr_auth->au_credcache->lock;
134         spin_lock(cache_lock);
135         if (atomic_read(&cred->cr_count) == 0)
136                 rpcauth_unhash_cred_locked(cred);
137         spin_unlock(cache_lock);
138 }
139
140 /*
141  * Initialize RPC credential cache
142  */
143 int
144 rpcauth_init_credcache(struct rpc_auth *auth)
145 {
146         struct rpc_cred_cache *new;
147         int i;
148
149         new = kmalloc(sizeof(*new), GFP_KERNEL);
150         if (!new)
151                 return -ENOMEM;
152         for (i = 0; i < RPC_CREDCACHE_NR; i++)
153                 INIT_HLIST_HEAD(&new->hashtable[i]);
154         spin_lock_init(&new->lock);
155         auth->au_credcache = new;
156         return 0;
157 }
158 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
159
160 /*
161  * Destroy a list of credentials
162  */
163 static inline
164 void rpcauth_destroy_credlist(struct list_head *head)
165 {
166         struct rpc_cred *cred;
167
168         while (!list_empty(head)) {
169                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
170                 list_del_init(&cred->cr_lru);
171                 put_rpccred(cred);
172         }
173 }
174
175 /*
176  * Clear the RPC credential cache, and delete those credentials
177  * that are not referenced.
178  */
179 void
180 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
181 {
182         LIST_HEAD(free);
183         struct hlist_head *head;
184         struct rpc_cred *cred;
185         int             i;
186
187         spin_lock(&rpc_credcache_lock);
188         spin_lock(&cache->lock);
189         for (i = 0; i < RPC_CREDCACHE_NR; i++) {
190                 head = &cache->hashtable[i];
191                 while (!hlist_empty(head)) {
192                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
193                         get_rpccred(cred);
194                         if (!list_empty(&cred->cr_lru)) {
195                                 list_del(&cred->cr_lru);
196                                 number_cred_unused--;
197                         }
198                         list_add_tail(&cred->cr_lru, &free);
199                         rpcauth_unhash_cred_locked(cred);
200                 }
201         }
202         spin_unlock(&cache->lock);
203         spin_unlock(&rpc_credcache_lock);
204         rpcauth_destroy_credlist(&free);
205 }
206
207 /*
208  * Destroy the RPC credential cache
209  */
210 void
211 rpcauth_destroy_credcache(struct rpc_auth *auth)
212 {
213         struct rpc_cred_cache *cache = auth->au_credcache;
214
215         if (cache) {
216                 auth->au_credcache = NULL;
217                 rpcauth_clear_credcache(cache);
218                 kfree(cache);
219         }
220 }
221 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
222
223
224 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
225
226 /*
227  * Remove stale credentials. Avoid sleeping inside the loop.
228  */
229 static int
230 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
231 {
232         spinlock_t *cache_lock;
233         struct rpc_cred *cred;
234         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
235
236         while (!list_empty(&cred_unused)) {
237                 cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru);
238                 list_del_init(&cred->cr_lru);
239                 number_cred_unused--;
240                 if (atomic_read(&cred->cr_count) != 0)
241                         continue;
242                 /* Enforce a 5 second garbage collection moratorium */
243                 if (time_in_range(cred->cr_expire, expired, jiffies) &&
244                     test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0)
245                         continue;
246                 cache_lock = &cred->cr_auth->au_credcache->lock;
247                 spin_lock(cache_lock);
248                 if (atomic_read(&cred->cr_count) == 0) {
249                         get_rpccred(cred);
250                         list_add_tail(&cred->cr_lru, free);
251                         rpcauth_unhash_cred_locked(cred);
252                         nr_to_scan--;
253                 }
254                 spin_unlock(cache_lock);
255                 if (nr_to_scan == 0)
256                         break;
257         }
258         return nr_to_scan;
259 }
260
261 /*
262  * Run memory cache shrinker.
263  */
264 static int
265 rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
266 {
267         LIST_HEAD(free);
268         int res;
269
270         if (list_empty(&cred_unused))
271                 return 0;
272         spin_lock(&rpc_credcache_lock);
273         nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
274         res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
275         spin_unlock(&rpc_credcache_lock);
276         rpcauth_destroy_credlist(&free);
277         return res;
278 }
279
280 /*
281  * Look up a process' credentials in the authentication cache
282  */
283 struct rpc_cred *
284 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
285                 int flags)
286 {
287         LIST_HEAD(free);
288         struct rpc_cred_cache *cache = auth->au_credcache;
289         struct hlist_node *pos;
290         struct rpc_cred *cred = NULL,
291                         *entry, *new;
292         unsigned int nr;
293
294         nr = hash_long(acred->uid, RPC_CREDCACHE_HASHBITS);
295
296         rcu_read_lock();
297         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
298                 if (!entry->cr_ops->crmatch(acred, entry, flags))
299                         continue;
300                 spin_lock(&cache->lock);
301                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
302                         spin_unlock(&cache->lock);
303                         continue;
304                 }
305                 cred = get_rpccred(entry);
306                 spin_unlock(&cache->lock);
307                 break;
308         }
309         rcu_read_unlock();
310
311         if (cred != NULL)
312                 goto found;
313
314         new = auth->au_ops->crcreate(auth, acred, flags);
315         if (IS_ERR(new)) {
316                 cred = new;
317                 goto out;
318         }
319
320         spin_lock(&cache->lock);
321         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
322                 if (!entry->cr_ops->crmatch(acred, entry, flags))
323                         continue;
324                 cred = get_rpccred(entry);
325                 break;
326         }
327         if (cred == NULL) {
328                 cred = new;
329                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
330                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
331         } else
332                 list_add_tail(&new->cr_lru, &free);
333         spin_unlock(&cache->lock);
334 found:
335         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
336                         && cred->cr_ops->cr_init != NULL
337                         && !(flags & RPCAUTH_LOOKUP_NEW)) {
338                 int res = cred->cr_ops->cr_init(auth, cred);
339                 if (res < 0) {
340                         put_rpccred(cred);
341                         cred = ERR_PTR(res);
342                 }
343         }
344         rpcauth_destroy_credlist(&free);
345 out:
346         return cred;
347 }
348 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
349
350 struct rpc_cred *
351 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
352 {
353         struct auth_cred acred = {
354                 .uid = current->fsuid,
355                 .gid = current->fsgid,
356                 .group_info = current->group_info,
357         };
358         struct rpc_cred *ret;
359
360         dprintk("RPC:       looking up %s cred\n",
361                 auth->au_ops->au_name);
362         get_group_info(acred.group_info);
363         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
364         put_group_info(acred.group_info);
365         return ret;
366 }
367
368 void
369 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
370                   struct rpc_auth *auth, const struct rpc_credops *ops)
371 {
372         INIT_HLIST_NODE(&cred->cr_hash);
373         INIT_LIST_HEAD(&cred->cr_lru);
374         atomic_set(&cred->cr_count, 1);
375         cred->cr_auth = auth;
376         cred->cr_ops = ops;
377         cred->cr_expire = jiffies;
378 #ifdef RPC_DEBUG
379         cred->cr_magic = RPCAUTH_CRED_MAGIC;
380 #endif
381         cred->cr_uid = acred->uid;
382 }
383 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
384
385 void
386 rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred)
387 {
388         task->tk_msg.rpc_cred = get_rpccred(cred);
389         dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
390                         cred->cr_auth->au_ops->au_name, cred);
391 }
392 EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
393
394 static void
395 rpcauth_bind_root_cred(struct rpc_task *task)
396 {
397         struct rpc_auth *auth = task->tk_client->cl_auth;
398         struct auth_cred acred = {
399                 .uid = 0,
400                 .gid = 0,
401         };
402         struct rpc_cred *ret;
403
404         dprintk("RPC: %5u looking up %s cred\n",
405                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
406         ret = auth->au_ops->lookup_cred(auth, &acred, 0);
407         if (!IS_ERR(ret))
408                 task->tk_msg.rpc_cred = ret;
409         else
410                 task->tk_status = PTR_ERR(ret);
411 }
412
413 static void
414 rpcauth_bind_new_cred(struct rpc_task *task)
415 {
416         struct rpc_auth *auth = task->tk_client->cl_auth;
417         struct rpc_cred *ret;
418
419         dprintk("RPC: %5u looking up %s cred\n",
420                 task->tk_pid, auth->au_ops->au_name);
421         ret = rpcauth_lookupcred(auth, 0);
422         if (!IS_ERR(ret))
423                 task->tk_msg.rpc_cred = ret;
424         else
425                 task->tk_status = PTR_ERR(ret);
426 }
427
428 void
429 rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
430 {
431         if (cred != NULL)
432                 cred->cr_ops->crbind(task, cred);
433         else if (flags & RPC_TASK_ROOTCREDS)
434                 rpcauth_bind_root_cred(task);
435         else
436                 rpcauth_bind_new_cred(task);
437 }
438
439 void
440 put_rpccred(struct rpc_cred *cred)
441 {
442         /* Fast path for unhashed credentials */
443         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
444                 goto need_lock;
445
446         if (!atomic_dec_and_test(&cred->cr_count))
447                 return;
448         goto out_destroy;
449 need_lock:
450         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
451                 return;
452         if (!list_empty(&cred->cr_lru)) {
453                 number_cred_unused--;
454                 list_del_init(&cred->cr_lru);
455         }
456         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
457                 rpcauth_unhash_cred(cred);
458         else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
459                 cred->cr_expire = jiffies;
460                 list_add_tail(&cred->cr_lru, &cred_unused);
461                 number_cred_unused++;
462                 spin_unlock(&rpc_credcache_lock);
463                 return;
464         }
465         spin_unlock(&rpc_credcache_lock);
466 out_destroy:
467         cred->cr_ops->crdestroy(cred);
468 }
469 EXPORT_SYMBOL_GPL(put_rpccred);
470
471 void
472 rpcauth_unbindcred(struct rpc_task *task)
473 {
474         struct rpc_cred *cred = task->tk_msg.rpc_cred;
475
476         dprintk("RPC: %5u releasing %s cred %p\n",
477                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
478
479         put_rpccred(cred);
480         task->tk_msg.rpc_cred = NULL;
481 }
482
483 __be32 *
484 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
485 {
486         struct rpc_cred *cred = task->tk_msg.rpc_cred;
487
488         dprintk("RPC: %5u marshaling %s cred %p\n",
489                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
490
491         return cred->cr_ops->crmarshal(task, p);
492 }
493
494 __be32 *
495 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
496 {
497         struct rpc_cred *cred = task->tk_msg.rpc_cred;
498
499         dprintk("RPC: %5u validating %s cred %p\n",
500                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
501
502         return cred->cr_ops->crvalidate(task, p);
503 }
504
505 int
506 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
507                 __be32 *data, void *obj)
508 {
509         struct rpc_cred *cred = task->tk_msg.rpc_cred;
510
511         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
512                         task->tk_pid, cred->cr_ops->cr_name, cred);
513         if (cred->cr_ops->crwrap_req)
514                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
515         /* By default, we encode the arguments normally. */
516         return rpc_call_xdrproc(encode, rqstp, data, obj);
517 }
518
519 int
520 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
521                 __be32 *data, void *obj)
522 {
523         struct rpc_cred *cred = task->tk_msg.rpc_cred;
524
525         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
526                         task->tk_pid, cred->cr_ops->cr_name, cred);
527         if (cred->cr_ops->crunwrap_resp)
528                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
529                                                    data, obj);
530         /* By default, we decode the arguments normally. */
531         return rpc_call_xdrproc(decode, rqstp, data, obj);
532 }
533
534 int
535 rpcauth_refreshcred(struct rpc_task *task)
536 {
537         struct rpc_cred *cred = task->tk_msg.rpc_cred;
538         int err;
539
540         dprintk("RPC: %5u refreshing %s cred %p\n",
541                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
542
543         err = cred->cr_ops->crrefresh(task);
544         if (err < 0)
545                 task->tk_status = err;
546         return err;
547 }
548
549 void
550 rpcauth_invalcred(struct rpc_task *task)
551 {
552         struct rpc_cred *cred = task->tk_msg.rpc_cred;
553
554         dprintk("RPC: %5u invalidating %s cred %p\n",
555                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
556         if (cred)
557                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
558 }
559
560 int
561 rpcauth_uptodatecred(struct rpc_task *task)
562 {
563         struct rpc_cred *cred = task->tk_msg.rpc_cred;
564
565         return cred == NULL ||
566                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
567 }
568
569 static struct shrinker rpc_cred_shrinker = {
570         .shrink = rpcauth_cache_shrinker,
571         .seeks = DEFAULT_SEEKS,
572 };
573
574 void __init rpcauth_init_module(void)
575 {
576         rpc_init_authunix();
577         rpc_init_generic_auth();
578         register_shrinker(&rpc_cred_shrinker);
579 }
580
581 void __exit rpcauth_remove_module(void)
582 {
583         unregister_shrinker(&rpc_cred_shrinker);
584 }