0c431c277af5be352e3c65b9fa4de99e25086e9b
[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 void
127 rpcauth_unhash_cred(struct rpc_cred *cred)
128 {
129         spinlock_t *cache_lock;
130
131         cache_lock = &cred->cr_auth->au_credcache->lock;
132         spin_lock(cache_lock);
133         if (atomic_read(&cred->cr_count) == 0)
134                 rpcauth_unhash_cred_locked(cred);
135         spin_unlock(cache_lock);
136 }
137
138 /*
139  * Initialize RPC credential cache
140  */
141 int
142 rpcauth_init_credcache(struct rpc_auth *auth)
143 {
144         struct rpc_cred_cache *new;
145         int i;
146
147         new = kmalloc(sizeof(*new), GFP_KERNEL);
148         if (!new)
149                 return -ENOMEM;
150         for (i = 0; i < RPC_CREDCACHE_NR; i++)
151                 INIT_HLIST_HEAD(&new->hashtable[i]);
152         spin_lock_init(&new->lock);
153         auth->au_credcache = new;
154         return 0;
155 }
156 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
157
158 /*
159  * Destroy a list of credentials
160  */
161 static inline
162 void rpcauth_destroy_credlist(struct list_head *head)
163 {
164         struct rpc_cred *cred;
165
166         while (!list_empty(head)) {
167                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
168                 list_del_init(&cred->cr_lru);
169                 put_rpccred(cred);
170         }
171 }
172
173 /*
174  * Clear the RPC credential cache, and delete those credentials
175  * that are not referenced.
176  */
177 void
178 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
179 {
180         LIST_HEAD(free);
181         struct hlist_head *head;
182         struct rpc_cred *cred;
183         int             i;
184
185         spin_lock(&rpc_credcache_lock);
186         spin_lock(&cache->lock);
187         for (i = 0; i < RPC_CREDCACHE_NR; i++) {
188                 head = &cache->hashtable[i];
189                 while (!hlist_empty(head)) {
190                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
191                         get_rpccred(cred);
192                         if (!list_empty(&cred->cr_lru)) {
193                                 list_del(&cred->cr_lru);
194                                 number_cred_unused--;
195                         }
196                         list_add_tail(&cred->cr_lru, &free);
197                         rpcauth_unhash_cred_locked(cred);
198                 }
199         }
200         spin_unlock(&cache->lock);
201         spin_unlock(&rpc_credcache_lock);
202         rpcauth_destroy_credlist(&free);
203 }
204
205 /*
206  * Destroy the RPC credential cache
207  */
208 void
209 rpcauth_destroy_credcache(struct rpc_auth *auth)
210 {
211         struct rpc_cred_cache *cache = auth->au_credcache;
212
213         if (cache) {
214                 auth->au_credcache = NULL;
215                 rpcauth_clear_credcache(cache);
216                 kfree(cache);
217         }
218 }
219 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
220
221
222 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
223
224 /*
225  * Remove stale credentials. Avoid sleeping inside the loop.
226  */
227 static int
228 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
229 {
230         spinlock_t *cache_lock;
231         struct rpc_cred *cred, *next;
232         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
233
234         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
235
236                 /* Enforce a 60 second garbage collection moratorium */
237                 if (time_in_range_open(cred->cr_expire, expired, jiffies) &&
238                     test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
239                         continue;
240
241                 list_del_init(&cred->cr_lru);
242                 number_cred_unused--;
243                 if (atomic_read(&cred->cr_count) != 0)
244                         continue;
245
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         struct rpc_cred *ret;
355         const struct cred *cred = current_cred();
356
357         dprintk("RPC:       looking up %s cred\n",
358                 auth->au_ops->au_name);
359
360         memset(&acred, 0, sizeof(acred));
361         acred.uid = cred->fsuid;
362         acred.gid = cred->fsgid;
363         acred.group_info = get_group_info(((struct cred *)cred)->group_info);
364
365         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
366         put_group_info(acred.group_info);
367         return ret;
368 }
369
370 void
371 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
372                   struct rpc_auth *auth, const struct rpc_credops *ops)
373 {
374         INIT_HLIST_NODE(&cred->cr_hash);
375         INIT_LIST_HEAD(&cred->cr_lru);
376         atomic_set(&cred->cr_count, 1);
377         cred->cr_auth = auth;
378         cred->cr_ops = ops;
379         cred->cr_expire = jiffies;
380 #ifdef RPC_DEBUG
381         cred->cr_magic = RPCAUTH_CRED_MAGIC;
382 #endif
383         cred->cr_uid = acred->uid;
384 }
385 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
386
387 void
388 rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred)
389 {
390         task->tk_msg.rpc_cred = get_rpccred(cred);
391         dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
392                         cred->cr_auth->au_ops->au_name, cred);
393 }
394 EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
395
396 static void
397 rpcauth_bind_root_cred(struct rpc_task *task)
398 {
399         struct rpc_auth *auth = task->tk_client->cl_auth;
400         struct auth_cred acred = {
401                 .uid = 0,
402                 .gid = 0,
403         };
404         struct rpc_cred *ret;
405
406         dprintk("RPC: %5u looking up %s cred\n",
407                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
408         ret = auth->au_ops->lookup_cred(auth, &acred, 0);
409         if (!IS_ERR(ret))
410                 task->tk_msg.rpc_cred = ret;
411         else
412                 task->tk_status = PTR_ERR(ret);
413 }
414
415 static void
416 rpcauth_bind_new_cred(struct rpc_task *task)
417 {
418         struct rpc_auth *auth = task->tk_client->cl_auth;
419         struct rpc_cred *ret;
420
421         dprintk("RPC: %5u looking up %s cred\n",
422                 task->tk_pid, auth->au_ops->au_name);
423         ret = rpcauth_lookupcred(auth, 0);
424         if (!IS_ERR(ret))
425                 task->tk_msg.rpc_cred = ret;
426         else
427                 task->tk_status = PTR_ERR(ret);
428 }
429
430 void
431 rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
432 {
433         if (cred != NULL)
434                 cred->cr_ops->crbind(task, cred);
435         else if (flags & RPC_TASK_ROOTCREDS)
436                 rpcauth_bind_root_cred(task);
437         else
438                 rpcauth_bind_new_cred(task);
439 }
440
441 void
442 put_rpccred(struct rpc_cred *cred)
443 {
444         /* Fast path for unhashed credentials */
445         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
446                 goto need_lock;
447
448         if (!atomic_dec_and_test(&cred->cr_count))
449                 return;
450         goto out_destroy;
451 need_lock:
452         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
453                 return;
454         if (!list_empty(&cred->cr_lru)) {
455                 number_cred_unused--;
456                 list_del_init(&cred->cr_lru);
457         }
458         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
459                 rpcauth_unhash_cred(cred);
460         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
461                 cred->cr_expire = jiffies;
462                 list_add_tail(&cred->cr_lru, &cred_unused);
463                 number_cred_unused++;
464                 spin_unlock(&rpc_credcache_lock);
465                 return;
466         }
467         spin_unlock(&rpc_credcache_lock);
468 out_destroy:
469         cred->cr_ops->crdestroy(cred);
470 }
471 EXPORT_SYMBOL_GPL(put_rpccred);
472
473 void
474 rpcauth_unbindcred(struct rpc_task *task)
475 {
476         struct rpc_cred *cred = task->tk_msg.rpc_cred;
477
478         dprintk("RPC: %5u releasing %s cred %p\n",
479                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
480
481         put_rpccred(cred);
482         task->tk_msg.rpc_cred = NULL;
483 }
484
485 __be32 *
486 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
487 {
488         struct rpc_cred *cred = task->tk_msg.rpc_cred;
489
490         dprintk("RPC: %5u marshaling %s cred %p\n",
491                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
492
493         return cred->cr_ops->crmarshal(task, p);
494 }
495
496 __be32 *
497 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
498 {
499         struct rpc_cred *cred = task->tk_msg.rpc_cred;
500
501         dprintk("RPC: %5u validating %s cred %p\n",
502                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
503
504         return cred->cr_ops->crvalidate(task, p);
505 }
506
507 int
508 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
509                 __be32 *data, void *obj)
510 {
511         struct rpc_cred *cred = task->tk_msg.rpc_cred;
512
513         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
514                         task->tk_pid, cred->cr_ops->cr_name, cred);
515         if (cred->cr_ops->crwrap_req)
516                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
517         /* By default, we encode the arguments normally. */
518         return encode(rqstp, data, obj);
519 }
520
521 int
522 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
523                 __be32 *data, void *obj)
524 {
525         struct rpc_cred *cred = task->tk_msg.rpc_cred;
526
527         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
528                         task->tk_pid, cred->cr_ops->cr_name, cred);
529         if (cred->cr_ops->crunwrap_resp)
530                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
531                                                    data, obj);
532         /* By default, we decode the arguments normally. */
533         return decode(rqstp, data, obj);
534 }
535
536 int
537 rpcauth_refreshcred(struct rpc_task *task)
538 {
539         struct rpc_cred *cred = task->tk_msg.rpc_cred;
540         int err;
541
542         dprintk("RPC: %5u refreshing %s cred %p\n",
543                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
544
545         err = cred->cr_ops->crrefresh(task);
546         if (err < 0)
547                 task->tk_status = err;
548         return err;
549 }
550
551 void
552 rpcauth_invalcred(struct rpc_task *task)
553 {
554         struct rpc_cred *cred = task->tk_msg.rpc_cred;
555
556         dprintk("RPC: %5u invalidating %s cred %p\n",
557                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
558         if (cred)
559                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
560 }
561
562 int
563 rpcauth_uptodatecred(struct rpc_task *task)
564 {
565         struct rpc_cred *cred = task->tk_msg.rpc_cred;
566
567         return cred == NULL ||
568                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
569 }
570
571 static struct shrinker rpc_cred_shrinker = {
572         .shrink = rpcauth_cache_shrinker,
573         .seeks = DEFAULT_SEEKS,
574 };
575
576 void __init rpcauth_init_module(void)
577 {
578         rpc_init_authunix();
579         rpc_init_generic_auth();
580         register_shrinker(&rpc_cred_shrinker);
581 }
582
583 void __exit rpcauth_remove_module(void)
584 {
585         unregister_shrinker(&rpc_cred_shrinker);
586 }