eca941ce298b6465507c2f672dc5bf44350fffe6
[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/sunrpc/clnt.h>
15 #include <linux/spinlock.h>
16
17 #ifdef RPC_DEBUG
18 # define RPCDBG_FACILITY        RPCDBG_AUTH
19 #endif
20
21 static DEFINE_SPINLOCK(rpc_authflavor_lock);
22 static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
23         &authnull_ops,          /* AUTH_NULL */
24         &authunix_ops,          /* AUTH_UNIX */
25         NULL,                   /* others can be loadable modules */
26 };
27
28 static LIST_HEAD(cred_unused);
29 static unsigned long number_cred_unused;
30
31 static u32
32 pseudoflavor_to_flavor(u32 flavor) {
33         if (flavor >= RPC_AUTH_MAXFLAVOR)
34                 return RPC_AUTH_GSS;
35         return flavor;
36 }
37
38 int
39 rpcauth_register(const struct rpc_authops *ops)
40 {
41         rpc_authflavor_t flavor;
42         int ret = -EPERM;
43
44         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
45                 return -EINVAL;
46         spin_lock(&rpc_authflavor_lock);
47         if (auth_flavors[flavor] == NULL) {
48                 auth_flavors[flavor] = ops;
49                 ret = 0;
50         }
51         spin_unlock(&rpc_authflavor_lock);
52         return ret;
53 }
54 EXPORT_SYMBOL_GPL(rpcauth_register);
55
56 int
57 rpcauth_unregister(const struct rpc_authops *ops)
58 {
59         rpc_authflavor_t flavor;
60         int ret = -EPERM;
61
62         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
63                 return -EINVAL;
64         spin_lock(&rpc_authflavor_lock);
65         if (auth_flavors[flavor] == ops) {
66                 auth_flavors[flavor] = NULL;
67                 ret = 0;
68         }
69         spin_unlock(&rpc_authflavor_lock);
70         return ret;
71 }
72 EXPORT_SYMBOL_GPL(rpcauth_unregister);
73
74 struct rpc_auth *
75 rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
76 {
77         struct rpc_auth         *auth;
78         const struct rpc_authops *ops;
79         u32                     flavor = pseudoflavor_to_flavor(pseudoflavor);
80
81         auth = ERR_PTR(-EINVAL);
82         if (flavor >= RPC_AUTH_MAXFLAVOR)
83                 goto out;
84
85 #ifdef CONFIG_KMOD
86         if ((ops = auth_flavors[flavor]) == NULL)
87                 request_module("rpc-auth-%u", flavor);
88 #endif
89         spin_lock(&rpc_authflavor_lock);
90         ops = auth_flavors[flavor];
91         if (ops == NULL || !try_module_get(ops->owner)) {
92                 spin_unlock(&rpc_authflavor_lock);
93                 goto out;
94         }
95         spin_unlock(&rpc_authflavor_lock);
96         auth = ops->create(clnt, pseudoflavor);
97         module_put(ops->owner);
98         if (IS_ERR(auth))
99                 return auth;
100         if (clnt->cl_auth)
101                 rpcauth_release(clnt->cl_auth);
102         clnt->cl_auth = auth;
103
104 out:
105         return auth;
106 }
107 EXPORT_SYMBOL_GPL(rpcauth_create);
108
109 void
110 rpcauth_release(struct rpc_auth *auth)
111 {
112         if (!atomic_dec_and_test(&auth->au_count))
113                 return;
114         auth->au_ops->destroy(auth);
115 }
116
117 static DEFINE_SPINLOCK(rpc_credcache_lock);
118
119 static void
120 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
121 {
122         hlist_del_rcu(&cred->cr_hash);
123         smp_mb__before_clear_bit();
124         clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
125 }
126
127 static void
128 rpcauth_unhash_cred(struct rpc_cred *cred)
129 {
130         spinlock_t *cache_lock;
131
132         cache_lock = &cred->cr_auth->au_credcache->lock;
133         spin_lock(cache_lock);
134         if (atomic_read(&cred->cr_count) == 0)
135                 rpcauth_unhash_cred_locked(cred);
136         spin_unlock(cache_lock);
137 }
138
139 /*
140  * Initialize RPC credential cache
141  */
142 int
143 rpcauth_init_credcache(struct rpc_auth *auth)
144 {
145         struct rpc_cred_cache *new;
146         int i;
147
148         new = kmalloc(sizeof(*new), GFP_KERNEL);
149         if (!new)
150                 return -ENOMEM;
151         for (i = 0; i < RPC_CREDCACHE_NR; i++)
152                 INIT_HLIST_HEAD(&new->hashtable[i]);
153         spin_lock_init(&new->lock);
154         auth->au_credcache = new;
155         return 0;
156 }
157 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
158
159 /*
160  * Destroy a list of credentials
161  */
162 static inline
163 void rpcauth_destroy_credlist(struct list_head *head)
164 {
165         struct rpc_cred *cred;
166
167         while (!list_empty(head)) {
168                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
169                 list_del_init(&cred->cr_lru);
170                 put_rpccred(cred);
171         }
172 }
173
174 /*
175  * Clear the RPC credential cache, and delete those credentials
176  * that are not referenced.
177  */
178 void
179 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
180 {
181         LIST_HEAD(free);
182         struct hlist_head *head;
183         struct rpc_cred *cred;
184         int             i;
185
186         spin_lock(&rpc_credcache_lock);
187         spin_lock(&cache->lock);
188         for (i = 0; i < RPC_CREDCACHE_NR; i++) {
189                 head = &cache->hashtable[i];
190                 while (!hlist_empty(head)) {
191                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
192                         get_rpccred(cred);
193                         if (!list_empty(&cred->cr_lru)) {
194                                 list_del(&cred->cr_lru);
195                                 number_cred_unused--;
196                         }
197                         list_add_tail(&cred->cr_lru, &free);
198                         rpcauth_unhash_cred_locked(cred);
199                 }
200         }
201         spin_unlock(&cache->lock);
202         spin_unlock(&rpc_credcache_lock);
203         rpcauth_destroy_credlist(&free);
204 }
205
206 /*
207  * Destroy the RPC credential cache
208  */
209 void
210 rpcauth_destroy_credcache(struct rpc_auth *auth)
211 {
212         struct rpc_cred_cache *cache = auth->au_credcache;
213
214         if (cache) {
215                 auth->au_credcache = NULL;
216                 rpcauth_clear_credcache(cache);
217                 kfree(cache);
218         }
219 }
220 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
221
222 /*
223  * Remove stale credentials. Avoid sleeping inside the loop.
224  */
225 static int
226 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
227 {
228         spinlock_t *cache_lock;
229         struct rpc_cred *cred;
230
231         while (!list_empty(&cred_unused)) {
232                 cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru);
233                 list_del_init(&cred->cr_lru);
234                 number_cred_unused--;
235                 if (atomic_read(&cred->cr_count) != 0)
236                         continue;
237                 cache_lock = &cred->cr_auth->au_credcache->lock;
238                 spin_lock(cache_lock);
239                 if (atomic_read(&cred->cr_count) == 0) {
240                         get_rpccred(cred);
241                         list_add_tail(&cred->cr_lru, free);
242                         rpcauth_unhash_cred_locked(cred);
243                         nr_to_scan--;
244                 }
245                 spin_unlock(cache_lock);
246                 if (nr_to_scan == 0)
247                         break;
248         }
249         return nr_to_scan;
250 }
251
252 /*
253  * Run memory cache shrinker.
254  */
255 static int
256 rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
257 {
258         LIST_HEAD(free);
259         int res;
260
261         if (list_empty(&cred_unused))
262                 return 0;
263         spin_lock(&rpc_credcache_lock);
264         nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
265         res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
266         spin_unlock(&rpc_credcache_lock);
267         rpcauth_destroy_credlist(&free);
268         return res;
269 }
270
271 /*
272  * Look up a process' credentials in the authentication cache
273  */
274 struct rpc_cred *
275 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
276                 int flags)
277 {
278         LIST_HEAD(free);
279         struct rpc_cred_cache *cache = auth->au_credcache;
280         struct hlist_node *pos;
281         struct rpc_cred *cred = NULL,
282                         *entry, *new;
283         int             nr = 0;
284
285         if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
286                 nr = acred->uid & RPC_CREDCACHE_MASK;
287
288         rcu_read_lock();
289         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
290                 if (!entry->cr_ops->crmatch(acred, entry, flags))
291                         continue;
292                 spin_lock(&cache->lock);
293                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
294                         spin_unlock(&cache->lock);
295                         continue;
296                 }
297                 cred = get_rpccred(entry);
298                 spin_unlock(&cache->lock);
299                 break;
300         }
301         rcu_read_unlock();
302
303         if (cred != NULL)
304                 goto found;
305
306         new = auth->au_ops->crcreate(auth, acred, flags);
307         if (IS_ERR(new)) {
308                 cred = new;
309                 goto out;
310         }
311
312         spin_lock(&cache->lock);
313         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
314                 if (!entry->cr_ops->crmatch(acred, entry, flags))
315                         continue;
316                 cred = get_rpccred(entry);
317                 break;
318         }
319         if (cred == NULL) {
320                 cred = new;
321                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
322                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
323         } else
324                 list_add_tail(&new->cr_lru, &free);
325         spin_unlock(&cache->lock);
326 found:
327         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
328                         && cred->cr_ops->cr_init != NULL
329                         && !(flags & RPCAUTH_LOOKUP_NEW)) {
330                 int res = cred->cr_ops->cr_init(auth, cred);
331                 if (res < 0) {
332                         put_rpccred(cred);
333                         cred = ERR_PTR(res);
334                 }
335         }
336         rpcauth_destroy_credlist(&free);
337 out:
338         return cred;
339 }
340 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
341
342 struct rpc_cred *
343 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
344 {
345         struct auth_cred acred = {
346                 .uid = current->fsuid,
347                 .gid = current->fsgid,
348                 .group_info = current->group_info,
349         };
350         struct rpc_cred *ret;
351
352         dprintk("RPC:       looking up %s cred\n",
353                 auth->au_ops->au_name);
354         get_group_info(acred.group_info);
355         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
356         put_group_info(acred.group_info);
357         return ret;
358 }
359 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
360
361 void
362 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
363                   struct rpc_auth *auth, const struct rpc_credops *ops)
364 {
365         INIT_HLIST_NODE(&cred->cr_hash);
366         INIT_LIST_HEAD(&cred->cr_lru);
367         atomic_set(&cred->cr_count, 1);
368         cred->cr_auth = auth;
369         cred->cr_ops = ops;
370         cred->cr_expire = jiffies;
371 #ifdef RPC_DEBUG
372         cred->cr_magic = RPCAUTH_CRED_MAGIC;
373 #endif
374         cred->cr_uid = acred->uid;
375 }
376 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
377
378 struct rpc_cred *
379 rpcauth_bindcred(struct rpc_task *task)
380 {
381         struct rpc_auth *auth = task->tk_client->cl_auth;
382         struct auth_cred acred = {
383                 .uid = current->fsuid,
384                 .gid = current->fsgid,
385                 .group_info = current->group_info,
386         };
387         struct rpc_cred *ret;
388         int flags = 0;
389
390         dprintk("RPC: %5u looking up %s cred\n",
391                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
392         get_group_info(acred.group_info);
393         if (task->tk_flags & RPC_TASK_ROOTCREDS)
394                 flags |= RPCAUTH_LOOKUP_ROOTCREDS;
395         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
396         if (!IS_ERR(ret))
397                 task->tk_msg.rpc_cred = ret;
398         else
399                 task->tk_status = PTR_ERR(ret);
400         put_group_info(acred.group_info);
401         return ret;
402 }
403
404 void
405 rpcauth_holdcred(struct rpc_task *task)
406 {
407         struct rpc_cred *cred = task->tk_msg.rpc_cred;
408         if (cred != NULL) {
409                 get_rpccred(cred);
410                 dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
411                                 cred->cr_auth->au_ops->au_name, cred);
412         }
413 }
414
415 void
416 put_rpccred(struct rpc_cred *cred)
417 {
418         /* Fast path for unhashed credentials */
419         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
420                 goto need_lock;
421
422         if (!atomic_dec_and_test(&cred->cr_count))
423                 return;
424         goto out_destroy;
425 need_lock:
426         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
427                 return;
428         if (!list_empty(&cred->cr_lru)) {
429                 number_cred_unused--;
430                 list_del_init(&cred->cr_lru);
431         }
432         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
433                 rpcauth_unhash_cred(cred);
434         else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
435                 cred->cr_expire = jiffies;
436                 list_add_tail(&cred->cr_lru, &cred_unused);
437                 number_cred_unused++;
438                 spin_unlock(&rpc_credcache_lock);
439                 return;
440         }
441         spin_unlock(&rpc_credcache_lock);
442 out_destroy:
443         cred->cr_ops->crdestroy(cred);
444 }
445 EXPORT_SYMBOL_GPL(put_rpccred);
446
447 void
448 rpcauth_unbindcred(struct rpc_task *task)
449 {
450         struct rpc_cred *cred = task->tk_msg.rpc_cred;
451
452         dprintk("RPC: %5u releasing %s cred %p\n",
453                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
454
455         put_rpccred(cred);
456         task->tk_msg.rpc_cred = NULL;
457 }
458
459 __be32 *
460 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
461 {
462         struct rpc_cred *cred = task->tk_msg.rpc_cred;
463
464         dprintk("RPC: %5u marshaling %s cred %p\n",
465                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
466
467         return cred->cr_ops->crmarshal(task, p);
468 }
469
470 __be32 *
471 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
472 {
473         struct rpc_cred *cred = task->tk_msg.rpc_cred;
474
475         dprintk("RPC: %5u validating %s cred %p\n",
476                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
477
478         return cred->cr_ops->crvalidate(task, p);
479 }
480
481 int
482 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
483                 __be32 *data, void *obj)
484 {
485         struct rpc_cred *cred = task->tk_msg.rpc_cred;
486
487         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
488                         task->tk_pid, cred->cr_ops->cr_name, cred);
489         if (cred->cr_ops->crwrap_req)
490                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
491         /* By default, we encode the arguments normally. */
492         return rpc_call_xdrproc(encode, rqstp, data, obj);
493 }
494
495 int
496 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
497                 __be32 *data, void *obj)
498 {
499         struct rpc_cred *cred = task->tk_msg.rpc_cred;
500
501         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
502                         task->tk_pid, cred->cr_ops->cr_name, cred);
503         if (cred->cr_ops->crunwrap_resp)
504                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
505                                                    data, obj);
506         /* By default, we decode the arguments normally. */
507         return rpc_call_xdrproc(decode, rqstp, data, obj);
508 }
509
510 int
511 rpcauth_refreshcred(struct rpc_task *task)
512 {
513         struct rpc_cred *cred = task->tk_msg.rpc_cred;
514         int err;
515
516         dprintk("RPC: %5u refreshing %s cred %p\n",
517                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
518
519         err = cred->cr_ops->crrefresh(task);
520         if (err < 0)
521                 task->tk_status = err;
522         return err;
523 }
524
525 void
526 rpcauth_invalcred(struct rpc_task *task)
527 {
528         struct rpc_cred *cred = task->tk_msg.rpc_cred;
529
530         dprintk("RPC: %5u invalidating %s cred %p\n",
531                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
532         if (cred)
533                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
534 }
535
536 int
537 rpcauth_uptodatecred(struct rpc_task *task)
538 {
539         struct rpc_cred *cred = task->tk_msg.rpc_cred;
540
541         return cred == NULL ||
542                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
543 }
544
545 static struct shrinker rpc_cred_shrinker = {
546         .shrink = rpcauth_cache_shrinker,
547         .seeks = DEFAULT_SEEKS,
548 };
549
550 void __init rpcauth_init_module(void)
551 {
552         rpc_init_authunix();
553         register_shrinker(&rpc_cred_shrinker);
554 }
555
556 void __exit rpcauth_remove_module(void)
557 {
558         unregister_shrinker(&rpc_cred_shrinker);
559 }