sunrpc: use vfs_path_lookup
[linux-2.6] / 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 #include <linux/smp_lock.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
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
73 struct rpc_auth *
74 rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
75 {
76         struct rpc_auth         *auth;
77         const struct rpc_authops *ops;
78         u32                     flavor = pseudoflavor_to_flavor(pseudoflavor);
79
80         auth = ERR_PTR(-EINVAL);
81         if (flavor >= RPC_AUTH_MAXFLAVOR)
82                 goto out;
83
84 #ifdef CONFIG_KMOD
85         if ((ops = auth_flavors[flavor]) == NULL)
86                 request_module("rpc-auth-%u", flavor);
87 #endif
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
107 void
108 rpcauth_release(struct rpc_auth *auth)
109 {
110         if (!atomic_dec_and_test(&auth->au_count))
111                 return;
112         auth->au_ops->destroy(auth);
113 }
114
115 static DEFINE_SPINLOCK(rpc_credcache_lock);
116
117 static void
118 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
119 {
120         hlist_del_rcu(&cred->cr_hash);
121         smp_mb__before_clear_bit();
122         clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
123 }
124
125 static void
126 rpcauth_unhash_cred(struct rpc_cred *cred)
127 {
128         spinlock_t *cache_lock;
129
130         cache_lock = &cred->cr_auth->au_credcache->lock;
131         spin_lock(cache_lock);
132         if (atomic_read(&cred->cr_count) == 0)
133                 rpcauth_unhash_cred_locked(cred);
134         spin_unlock(cache_lock);
135 }
136
137 /*
138  * Initialize RPC credential cache
139  */
140 int
141 rpcauth_init_credcache(struct rpc_auth *auth)
142 {
143         struct rpc_cred_cache *new;
144         int i;
145
146         new = kmalloc(sizeof(*new), GFP_KERNEL);
147         if (!new)
148                 return -ENOMEM;
149         for (i = 0; i < RPC_CREDCACHE_NR; i++)
150                 INIT_HLIST_HEAD(&new->hashtable[i]);
151         spin_lock_init(&new->lock);
152         auth->au_credcache = new;
153         return 0;
154 }
155
156 /*
157  * Destroy a list of credentials
158  */
159 static inline
160 void rpcauth_destroy_credlist(struct list_head *head)
161 {
162         struct rpc_cred *cred;
163
164         while (!list_empty(head)) {
165                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
166                 list_del_init(&cred->cr_lru);
167                 put_rpccred(cred);
168         }
169 }
170
171 /*
172  * Clear the RPC credential cache, and delete those credentials
173  * that are not referenced.
174  */
175 void
176 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
177 {
178         LIST_HEAD(free);
179         struct hlist_head *head;
180         struct rpc_cred *cred;
181         int             i;
182
183         spin_lock(&rpc_credcache_lock);
184         spin_lock(&cache->lock);
185         for (i = 0; i < RPC_CREDCACHE_NR; i++) {
186                 head = &cache->hashtable[i];
187                 while (!hlist_empty(head)) {
188                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
189                         get_rpccred(cred);
190                         if (!list_empty(&cred->cr_lru)) {
191                                 list_del(&cred->cr_lru);
192                                 number_cred_unused--;
193                         }
194                         list_add_tail(&cred->cr_lru, &free);
195                         rpcauth_unhash_cred_locked(cred);
196                 }
197         }
198         spin_unlock(&cache->lock);
199         spin_unlock(&rpc_credcache_lock);
200         rpcauth_destroy_credlist(&free);
201 }
202
203 /*
204  * Destroy the RPC credential cache
205  */
206 void
207 rpcauth_destroy_credcache(struct rpc_auth *auth)
208 {
209         struct rpc_cred_cache *cache = auth->au_credcache;
210
211         if (cache) {
212                 auth->au_credcache = NULL;
213                 rpcauth_clear_credcache(cache);
214                 kfree(cache);
215         }
216 }
217
218 /*
219  * Remove stale credentials. Avoid sleeping inside the loop.
220  */
221 static int
222 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
223 {
224         spinlock_t *cache_lock;
225         struct rpc_cred *cred;
226
227         while (!list_empty(&cred_unused)) {
228                 cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru);
229                 list_del_init(&cred->cr_lru);
230                 number_cred_unused--;
231                 if (atomic_read(&cred->cr_count) != 0)
232                         continue;
233                 cache_lock = &cred->cr_auth->au_credcache->lock;
234                 spin_lock(cache_lock);
235                 if (atomic_read(&cred->cr_count) == 0) {
236                         get_rpccred(cred);
237                         list_add_tail(&cred->cr_lru, free);
238                         rpcauth_unhash_cred_locked(cred);
239                         nr_to_scan--;
240                 }
241                 spin_unlock(cache_lock);
242                 if (nr_to_scan == 0)
243                         break;
244         }
245         return nr_to_scan;
246 }
247
248 /*
249  * Run memory cache shrinker.
250  */
251 static int
252 rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
253 {
254         LIST_HEAD(free);
255         int res;
256
257         if (list_empty(&cred_unused))
258                 return 0;
259         spin_lock(&rpc_credcache_lock);
260         nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
261         res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
262         spin_unlock(&rpc_credcache_lock);
263         rpcauth_destroy_credlist(&free);
264         return res;
265 }
266
267 /*
268  * Look up a process' credentials in the authentication cache
269  */
270 struct rpc_cred *
271 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
272                 int flags)
273 {
274         LIST_HEAD(free);
275         struct rpc_cred_cache *cache = auth->au_credcache;
276         struct hlist_node *pos;
277         struct rpc_cred *cred = NULL,
278                         *entry, *new;
279         int             nr = 0;
280
281         if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
282                 nr = acred->uid & RPC_CREDCACHE_MASK;
283
284         rcu_read_lock();
285         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
286                 if (!entry->cr_ops->crmatch(acred, entry, flags))
287                         continue;
288                 spin_lock(&cache->lock);
289                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
290                         spin_unlock(&cache->lock);
291                         continue;
292                 }
293                 cred = get_rpccred(entry);
294                 spin_unlock(&cache->lock);
295                 break;
296         }
297         rcu_read_unlock();
298
299         if (cred != NULL)
300                 goto found;
301
302         new = auth->au_ops->crcreate(auth, acred, flags);
303         if (IS_ERR(new)) {
304                 cred = new;
305                 goto out;
306         }
307
308         spin_lock(&cache->lock);
309         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
310                 if (!entry->cr_ops->crmatch(acred, entry, flags))
311                         continue;
312                 cred = get_rpccred(entry);
313                 break;
314         }
315         if (cred == NULL) {
316                 cred = new;
317                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
318                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
319         } else
320                 list_add_tail(&new->cr_lru, &free);
321         spin_unlock(&cache->lock);
322 found:
323         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
324                         && cred->cr_ops->cr_init != NULL
325                         && !(flags & RPCAUTH_LOOKUP_NEW)) {
326                 int res = cred->cr_ops->cr_init(auth, cred);
327                 if (res < 0) {
328                         put_rpccred(cred);
329                         cred = ERR_PTR(res);
330                 }
331         }
332         rpcauth_destroy_credlist(&free);
333 out:
334         return cred;
335 }
336
337 struct rpc_cred *
338 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
339 {
340         struct auth_cred acred = {
341                 .uid = current->fsuid,
342                 .gid = current->fsgid,
343                 .group_info = current->group_info,
344         };
345         struct rpc_cred *ret;
346
347         dprintk("RPC:       looking up %s cred\n",
348                 auth->au_ops->au_name);
349         get_group_info(acred.group_info);
350         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
351         put_group_info(acred.group_info);
352         return ret;
353 }
354
355 void
356 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
357                   struct rpc_auth *auth, const struct rpc_credops *ops)
358 {
359         INIT_HLIST_NODE(&cred->cr_hash);
360         INIT_LIST_HEAD(&cred->cr_lru);
361         atomic_set(&cred->cr_count, 1);
362         cred->cr_auth = auth;
363         cred->cr_ops = ops;
364         cred->cr_expire = jiffies;
365 #ifdef RPC_DEBUG
366         cred->cr_magic = RPCAUTH_CRED_MAGIC;
367 #endif
368         cred->cr_uid = acred->uid;
369 }
370 EXPORT_SYMBOL(rpcauth_init_cred);
371
372 struct rpc_cred *
373 rpcauth_bindcred(struct rpc_task *task)
374 {
375         struct rpc_auth *auth = task->tk_client->cl_auth;
376         struct auth_cred acred = {
377                 .uid = current->fsuid,
378                 .gid = current->fsgid,
379                 .group_info = current->group_info,
380         };
381         struct rpc_cred *ret;
382         int flags = 0;
383
384         dprintk("RPC: %5u looking up %s cred\n",
385                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
386         get_group_info(acred.group_info);
387         if (task->tk_flags & RPC_TASK_ROOTCREDS)
388                 flags |= RPCAUTH_LOOKUP_ROOTCREDS;
389         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
390         if (!IS_ERR(ret))
391                 task->tk_msg.rpc_cred = ret;
392         else
393                 task->tk_status = PTR_ERR(ret);
394         put_group_info(acred.group_info);
395         return ret;
396 }
397
398 void
399 rpcauth_holdcred(struct rpc_task *task)
400 {
401         struct rpc_cred *cred = task->tk_msg.rpc_cred;
402         if (cred != NULL) {
403                 get_rpccred(cred);
404                 dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
405                                 cred->cr_auth->au_ops->au_name, cred);
406         }
407 }
408
409 void
410 put_rpccred(struct rpc_cred *cred)
411 {
412         /* Fast path for unhashed credentials */
413         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
414                 goto need_lock;
415
416         if (!atomic_dec_and_test(&cred->cr_count))
417                 return;
418         goto out_destroy;
419 need_lock:
420         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
421                 return;
422         if (!list_empty(&cred->cr_lru)) {
423                 number_cred_unused--;
424                 list_del_init(&cred->cr_lru);
425         }
426         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
427                 rpcauth_unhash_cred(cred);
428         else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
429                 cred->cr_expire = jiffies;
430                 list_add_tail(&cred->cr_lru, &cred_unused);
431                 number_cred_unused++;
432                 spin_unlock(&rpc_credcache_lock);
433                 return;
434         }
435         spin_unlock(&rpc_credcache_lock);
436 out_destroy:
437         cred->cr_ops->crdestroy(cred);
438 }
439
440 void
441 rpcauth_unbindcred(struct rpc_task *task)
442 {
443         struct rpc_cred *cred = task->tk_msg.rpc_cred;
444
445         dprintk("RPC: %5u releasing %s cred %p\n",
446                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
447
448         put_rpccred(cred);
449         task->tk_msg.rpc_cred = NULL;
450 }
451
452 __be32 *
453 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
454 {
455         struct rpc_cred *cred = task->tk_msg.rpc_cred;
456
457         dprintk("RPC: %5u marshaling %s cred %p\n",
458                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
459
460         return cred->cr_ops->crmarshal(task, p);
461 }
462
463 __be32 *
464 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
465 {
466         struct rpc_cred *cred = task->tk_msg.rpc_cred;
467
468         dprintk("RPC: %5u validating %s cred %p\n",
469                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
470
471         return cred->cr_ops->crvalidate(task, p);
472 }
473
474 int
475 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
476                 __be32 *data, void *obj)
477 {
478         struct rpc_cred *cred = task->tk_msg.rpc_cred;
479         int ret;
480
481         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
482                         task->tk_pid, cred->cr_ops->cr_name, cred);
483         if (cred->cr_ops->crwrap_req)
484                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
485         /* By default, we encode the arguments normally. */
486         lock_kernel();
487         ret = encode(rqstp, data, obj);
488         unlock_kernel();
489         return ret;
490 }
491
492 int
493 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
494                 __be32 *data, void *obj)
495 {
496         struct rpc_cred *cred = task->tk_msg.rpc_cred;
497         int ret;
498
499         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
500                         task->tk_pid, cred->cr_ops->cr_name, cred);
501         if (cred->cr_ops->crunwrap_resp)
502                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
503                                                    data, obj);
504         /* By default, we decode the arguments normally. */
505         lock_kernel();
506         ret = decode(rqstp, data, obj);
507         unlock_kernel();
508         return ret;
509 }
510
511 int
512 rpcauth_refreshcred(struct rpc_task *task)
513 {
514         struct rpc_cred *cred = task->tk_msg.rpc_cred;
515         int err;
516
517         dprintk("RPC: %5u refreshing %s cred %p\n",
518                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
519
520         err = cred->cr_ops->crrefresh(task);
521         if (err < 0)
522                 task->tk_status = err;
523         return err;
524 }
525
526 void
527 rpcauth_invalcred(struct rpc_task *task)
528 {
529         struct rpc_cred *cred = task->tk_msg.rpc_cred;
530
531         dprintk("RPC: %5u invalidating %s cred %p\n",
532                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
533         if (cred)
534                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
535 }
536
537 int
538 rpcauth_uptodatecred(struct rpc_task *task)
539 {
540         struct rpc_cred *cred = task->tk_msg.rpc_cred;
541
542         return cred == NULL ||
543                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
544 }
545
546 static struct shrinker rpc_cred_shrinker = {
547         .shrink = rpcauth_cache_shrinker,
548         .seeks = DEFAULT_SEEKS,
549 };
550
551 void __init rpcauth_init_module(void)
552 {
553         rpc_init_authunix();
554         register_shrinker(&rpc_cred_shrinker);
555 }
556
557 void __exit rpcauth_remove_module(void)
558 {
559         unregister_shrinker(&rpc_cred_shrinker);
560 }