net: Remove CONFIG_KMOD from net/ (towards removing CONFIG_KMOD entirely)
[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;
232         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
233
234         while (!list_empty(&cred_unused)) {
235                 cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru);
236                 list_del_init(&cred->cr_lru);
237                 number_cred_unused--;
238                 if (atomic_read(&cred->cr_count) != 0)
239                         continue;
240                 /* Enforce a 5 second garbage collection moratorium */
241                 if (time_in_range(cred->cr_expire, expired, jiffies) &&
242                     test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0)
243                         continue;
244                 cache_lock = &cred->cr_auth->au_credcache->lock;
245                 spin_lock(cache_lock);
246                 if (atomic_read(&cred->cr_count) == 0) {
247                         get_rpccred(cred);
248                         list_add_tail(&cred->cr_lru, free);
249                         rpcauth_unhash_cred_locked(cred);
250                         nr_to_scan--;
251                 }
252                 spin_unlock(cache_lock);
253                 if (nr_to_scan == 0)
254                         break;
255         }
256         return nr_to_scan;
257 }
258
259 /*
260  * Run memory cache shrinker.
261  */
262 static int
263 rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
264 {
265         LIST_HEAD(free);
266         int res;
267
268         if (list_empty(&cred_unused))
269                 return 0;
270         spin_lock(&rpc_credcache_lock);
271         nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
272         res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
273         spin_unlock(&rpc_credcache_lock);
274         rpcauth_destroy_credlist(&free);
275         return res;
276 }
277
278 /*
279  * Look up a process' credentials in the authentication cache
280  */
281 struct rpc_cred *
282 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
283                 int flags)
284 {
285         LIST_HEAD(free);
286         struct rpc_cred_cache *cache = auth->au_credcache;
287         struct hlist_node *pos;
288         struct rpc_cred *cred = NULL,
289                         *entry, *new;
290         unsigned int nr;
291
292         nr = hash_long(acred->uid, RPC_CREDCACHE_HASHBITS);
293
294         rcu_read_lock();
295         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
296                 if (!entry->cr_ops->crmatch(acred, entry, flags))
297                         continue;
298                 spin_lock(&cache->lock);
299                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
300                         spin_unlock(&cache->lock);
301                         continue;
302                 }
303                 cred = get_rpccred(entry);
304                 spin_unlock(&cache->lock);
305                 break;
306         }
307         rcu_read_unlock();
308
309         if (cred != NULL)
310                 goto found;
311
312         new = auth->au_ops->crcreate(auth, acred, flags);
313         if (IS_ERR(new)) {
314                 cred = new;
315                 goto out;
316         }
317
318         spin_lock(&cache->lock);
319         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
320                 if (!entry->cr_ops->crmatch(acred, entry, flags))
321                         continue;
322                 cred = get_rpccred(entry);
323                 break;
324         }
325         if (cred == NULL) {
326                 cred = new;
327                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
328                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
329         } else
330                 list_add_tail(&new->cr_lru, &free);
331         spin_unlock(&cache->lock);
332 found:
333         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
334                         && cred->cr_ops->cr_init != NULL
335                         && !(flags & RPCAUTH_LOOKUP_NEW)) {
336                 int res = cred->cr_ops->cr_init(auth, cred);
337                 if (res < 0) {
338                         put_rpccred(cred);
339                         cred = ERR_PTR(res);
340                 }
341         }
342         rpcauth_destroy_credlist(&free);
343 out:
344         return cred;
345 }
346 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
347
348 struct rpc_cred *
349 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
350 {
351         struct auth_cred acred = {
352                 .uid = current->fsuid,
353                 .gid = current->fsgid,
354                 .group_info = current->group_info,
355         };
356         struct rpc_cred *ret;
357
358         dprintk("RPC:       looking up %s cred\n",
359                 auth->au_ops->au_name);
360         get_group_info(acred.group_info);
361         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
362         put_group_info(acred.group_info);
363         return ret;
364 }
365
366 void
367 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
368                   struct rpc_auth *auth, const struct rpc_credops *ops)
369 {
370         INIT_HLIST_NODE(&cred->cr_hash);
371         INIT_LIST_HEAD(&cred->cr_lru);
372         atomic_set(&cred->cr_count, 1);
373         cred->cr_auth = auth;
374         cred->cr_ops = ops;
375         cred->cr_expire = jiffies;
376 #ifdef RPC_DEBUG
377         cred->cr_magic = RPCAUTH_CRED_MAGIC;
378 #endif
379         cred->cr_uid = acred->uid;
380 }
381 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
382
383 void
384 rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred)
385 {
386         task->tk_msg.rpc_cred = get_rpccred(cred);
387         dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
388                         cred->cr_auth->au_ops->au_name, cred);
389 }
390 EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
391
392 static void
393 rpcauth_bind_root_cred(struct rpc_task *task)
394 {
395         struct rpc_auth *auth = task->tk_client->cl_auth;
396         struct auth_cred acred = {
397                 .uid = 0,
398                 .gid = 0,
399         };
400         struct rpc_cred *ret;
401
402         dprintk("RPC: %5u looking up %s cred\n",
403                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
404         ret = auth->au_ops->lookup_cred(auth, &acred, 0);
405         if (!IS_ERR(ret))
406                 task->tk_msg.rpc_cred = ret;
407         else
408                 task->tk_status = PTR_ERR(ret);
409 }
410
411 static void
412 rpcauth_bind_new_cred(struct rpc_task *task)
413 {
414         struct rpc_auth *auth = task->tk_client->cl_auth;
415         struct rpc_cred *ret;
416
417         dprintk("RPC: %5u looking up %s cred\n",
418                 task->tk_pid, auth->au_ops->au_name);
419         ret = rpcauth_lookupcred(auth, 0);
420         if (!IS_ERR(ret))
421                 task->tk_msg.rpc_cred = ret;
422         else
423                 task->tk_status = PTR_ERR(ret);
424 }
425
426 void
427 rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
428 {
429         if (cred != NULL)
430                 cred->cr_ops->crbind(task, cred);
431         else if (flags & RPC_TASK_ROOTCREDS)
432                 rpcauth_bind_root_cred(task);
433         else
434                 rpcauth_bind_new_cred(task);
435 }
436
437 void
438 put_rpccred(struct rpc_cred *cred)
439 {
440         /* Fast path for unhashed credentials */
441         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
442                 goto need_lock;
443
444         if (!atomic_dec_and_test(&cred->cr_count))
445                 return;
446         goto out_destroy;
447 need_lock:
448         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
449                 return;
450         if (!list_empty(&cred->cr_lru)) {
451                 number_cred_unused--;
452                 list_del_init(&cred->cr_lru);
453         }
454         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
455                 rpcauth_unhash_cred(cred);
456         else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
457                 cred->cr_expire = jiffies;
458                 list_add_tail(&cred->cr_lru, &cred_unused);
459                 number_cred_unused++;
460                 spin_unlock(&rpc_credcache_lock);
461                 return;
462         }
463         spin_unlock(&rpc_credcache_lock);
464 out_destroy:
465         cred->cr_ops->crdestroy(cred);
466 }
467 EXPORT_SYMBOL_GPL(put_rpccred);
468
469 void
470 rpcauth_unbindcred(struct rpc_task *task)
471 {
472         struct rpc_cred *cred = task->tk_msg.rpc_cred;
473
474         dprintk("RPC: %5u releasing %s cred %p\n",
475                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
476
477         put_rpccred(cred);
478         task->tk_msg.rpc_cred = NULL;
479 }
480
481 __be32 *
482 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
483 {
484         struct rpc_cred *cred = task->tk_msg.rpc_cred;
485
486         dprintk("RPC: %5u marshaling %s cred %p\n",
487                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
488
489         return cred->cr_ops->crmarshal(task, p);
490 }
491
492 __be32 *
493 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
494 {
495         struct rpc_cred *cred = task->tk_msg.rpc_cred;
496
497         dprintk("RPC: %5u validating %s cred %p\n",
498                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
499
500         return cred->cr_ops->crvalidate(task, p);
501 }
502
503 int
504 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
505                 __be32 *data, void *obj)
506 {
507         struct rpc_cred *cred = task->tk_msg.rpc_cred;
508
509         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
510                         task->tk_pid, cred->cr_ops->cr_name, cred);
511         if (cred->cr_ops->crwrap_req)
512                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
513         /* By default, we encode the arguments normally. */
514         return rpc_call_xdrproc(encode, rqstp, data, obj);
515 }
516
517 int
518 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
519                 __be32 *data, void *obj)
520 {
521         struct rpc_cred *cred = task->tk_msg.rpc_cred;
522
523         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
524                         task->tk_pid, cred->cr_ops->cr_name, cred);
525         if (cred->cr_ops->crunwrap_resp)
526                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
527                                                    data, obj);
528         /* By default, we decode the arguments normally. */
529         return rpc_call_xdrproc(decode, rqstp, data, obj);
530 }
531
532 int
533 rpcauth_refreshcred(struct rpc_task *task)
534 {
535         struct rpc_cred *cred = task->tk_msg.rpc_cred;
536         int err;
537
538         dprintk("RPC: %5u refreshing %s cred %p\n",
539                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
540
541         err = cred->cr_ops->crrefresh(task);
542         if (err < 0)
543                 task->tk_status = err;
544         return err;
545 }
546
547 void
548 rpcauth_invalcred(struct rpc_task *task)
549 {
550         struct rpc_cred *cred = task->tk_msg.rpc_cred;
551
552         dprintk("RPC: %5u invalidating %s cred %p\n",
553                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
554         if (cred)
555                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
556 }
557
558 int
559 rpcauth_uptodatecred(struct rpc_task *task)
560 {
561         struct rpc_cred *cred = task->tk_msg.rpc_cred;
562
563         return cred == NULL ||
564                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
565 }
566
567 static struct shrinker rpc_cred_shrinker = {
568         .shrink = rpcauth_cache_shrinker,
569         .seeks = DEFAULT_SEEKS,
570 };
571
572 void __init rpcauth_init_module(void)
573 {
574         rpc_init_authunix();
575         rpc_init_generic_auth();
576         register_shrinker(&rpc_cred_shrinker);
577 }
578
579 void __exit rpcauth_remove_module(void)
580 {
581         unregister_shrinker(&rpc_cred_shrinker);
582 }