Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / net / sunrpc / auth.c
blob727e506cacda0f7e6d95178c783ac695d2e4b1fb
1 /*
2 * linux/net/sunrpc/auth.c
4 * Generic RPC client authentication API.
6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7 */
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>
18 #ifdef RPC_DEBUG
19 # define RPCDBG_FACILITY RPCDBG_AUTH
20 #endif
22 #define RPC_CREDCACHE_DEFAULT_HASHBITS (4)
23 struct rpc_cred_cache {
24 struct hlist_head *hashtable;
25 unsigned int hashbits;
26 spinlock_t lock;
29 static unsigned int auth_hashbits = RPC_CREDCACHE_DEFAULT_HASHBITS;
31 static DEFINE_SPINLOCK(rpc_authflavor_lock);
32 static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
33 &authnull_ops, /* AUTH_NULL */
34 &authunix_ops, /* AUTH_UNIX */
35 NULL, /* others can be loadable modules */
38 static LIST_HEAD(cred_unused);
39 static unsigned long number_cred_unused;
41 #define MAX_HASHTABLE_BITS (14)
42 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
44 unsigned long num;
45 unsigned int nbits;
46 int ret;
48 if (!val)
49 goto out_inval;
50 ret = strict_strtoul(val, 0, &num);
51 if (ret == -EINVAL)
52 goto out_inval;
53 nbits = fls(num);
54 if (num > (1U << nbits))
55 nbits++;
56 if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
57 goto out_inval;
58 *(unsigned int *)kp->arg = nbits;
59 return 0;
60 out_inval:
61 return -EINVAL;
64 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
66 unsigned int nbits;
68 nbits = *(unsigned int *)kp->arg;
69 return sprintf(buffer, "%u", 1U << nbits);
72 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
74 static struct kernel_param_ops param_ops_hashtbl_sz = {
75 .set = param_set_hashtbl_sz,
76 .get = param_get_hashtbl_sz,
79 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
80 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
82 static u32
83 pseudoflavor_to_flavor(u32 flavor) {
84 if (flavor >= RPC_AUTH_MAXFLAVOR)
85 return RPC_AUTH_GSS;
86 return flavor;
89 int
90 rpcauth_register(const struct rpc_authops *ops)
92 rpc_authflavor_t flavor;
93 int ret = -EPERM;
95 if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
96 return -EINVAL;
97 spin_lock(&rpc_authflavor_lock);
98 if (auth_flavors[flavor] == NULL) {
99 auth_flavors[flavor] = ops;
100 ret = 0;
102 spin_unlock(&rpc_authflavor_lock);
103 return ret;
105 EXPORT_SYMBOL_GPL(rpcauth_register);
108 rpcauth_unregister(const struct rpc_authops *ops)
110 rpc_authflavor_t flavor;
111 int ret = -EPERM;
113 if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
114 return -EINVAL;
115 spin_lock(&rpc_authflavor_lock);
116 if (auth_flavors[flavor] == ops) {
117 auth_flavors[flavor] = NULL;
118 ret = 0;
120 spin_unlock(&rpc_authflavor_lock);
121 return ret;
123 EXPORT_SYMBOL_GPL(rpcauth_unregister);
125 struct rpc_auth *
126 rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
128 struct rpc_auth *auth;
129 const struct rpc_authops *ops;
130 u32 flavor = pseudoflavor_to_flavor(pseudoflavor);
132 auth = ERR_PTR(-EINVAL);
133 if (flavor >= RPC_AUTH_MAXFLAVOR)
134 goto out;
136 if ((ops = auth_flavors[flavor]) == NULL)
137 request_module("rpc-auth-%u", flavor);
138 spin_lock(&rpc_authflavor_lock);
139 ops = auth_flavors[flavor];
140 if (ops == NULL || !try_module_get(ops->owner)) {
141 spin_unlock(&rpc_authflavor_lock);
142 goto out;
144 spin_unlock(&rpc_authflavor_lock);
145 auth = ops->create(clnt, pseudoflavor);
146 module_put(ops->owner);
147 if (IS_ERR(auth))
148 return auth;
149 if (clnt->cl_auth)
150 rpcauth_release(clnt->cl_auth);
151 clnt->cl_auth = auth;
153 out:
154 return auth;
156 EXPORT_SYMBOL_GPL(rpcauth_create);
158 void
159 rpcauth_release(struct rpc_auth *auth)
161 if (!atomic_dec_and_test(&auth->au_count))
162 return;
163 auth->au_ops->destroy(auth);
166 static DEFINE_SPINLOCK(rpc_credcache_lock);
168 static void
169 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
171 hlist_del_rcu(&cred->cr_hash);
172 smp_mb__before_clear_bit();
173 clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
176 static int
177 rpcauth_unhash_cred(struct rpc_cred *cred)
179 spinlock_t *cache_lock;
180 int ret;
182 cache_lock = &cred->cr_auth->au_credcache->lock;
183 spin_lock(cache_lock);
184 ret = atomic_read(&cred->cr_count) == 0;
185 if (ret)
186 rpcauth_unhash_cred_locked(cred);
187 spin_unlock(cache_lock);
188 return ret;
192 * Initialize RPC credential cache
195 rpcauth_init_credcache(struct rpc_auth *auth)
197 struct rpc_cred_cache *new;
198 unsigned int hashsize;
200 new = kmalloc(sizeof(*new), GFP_KERNEL);
201 if (!new)
202 goto out_nocache;
203 new->hashbits = auth_hashbits;
204 hashsize = 1U << new->hashbits;
205 new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
206 if (!new->hashtable)
207 goto out_nohashtbl;
208 spin_lock_init(&new->lock);
209 auth->au_credcache = new;
210 return 0;
211 out_nohashtbl:
212 kfree(new);
213 out_nocache:
214 return -ENOMEM;
216 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
219 * Destroy a list of credentials
221 static inline
222 void rpcauth_destroy_credlist(struct list_head *head)
224 struct rpc_cred *cred;
226 while (!list_empty(head)) {
227 cred = list_entry(head->next, struct rpc_cred, cr_lru);
228 list_del_init(&cred->cr_lru);
229 put_rpccred(cred);
234 * Clear the RPC credential cache, and delete those credentials
235 * that are not referenced.
237 void
238 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
240 LIST_HEAD(free);
241 struct hlist_head *head;
242 struct rpc_cred *cred;
243 unsigned int hashsize = 1U << cache->hashbits;
244 int i;
246 spin_lock(&rpc_credcache_lock);
247 spin_lock(&cache->lock);
248 for (i = 0; i < hashsize; i++) {
249 head = &cache->hashtable[i];
250 while (!hlist_empty(head)) {
251 cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
252 get_rpccred(cred);
253 if (!list_empty(&cred->cr_lru)) {
254 list_del(&cred->cr_lru);
255 number_cred_unused--;
257 list_add_tail(&cred->cr_lru, &free);
258 rpcauth_unhash_cred_locked(cred);
261 spin_unlock(&cache->lock);
262 spin_unlock(&rpc_credcache_lock);
263 rpcauth_destroy_credlist(&free);
267 * Destroy the RPC credential cache
269 void
270 rpcauth_destroy_credcache(struct rpc_auth *auth)
272 struct rpc_cred_cache *cache = auth->au_credcache;
274 if (cache) {
275 auth->au_credcache = NULL;
276 rpcauth_clear_credcache(cache);
277 kfree(cache->hashtable);
278 kfree(cache);
281 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
284 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
287 * Remove stale credentials. Avoid sleeping inside the loop.
289 static int
290 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
292 spinlock_t *cache_lock;
293 struct rpc_cred *cred, *next;
294 unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
296 list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
298 if (nr_to_scan-- == 0)
299 break;
301 * Enforce a 60 second garbage collection moratorium
302 * Note that the cred_unused list must be time-ordered.
304 if (time_in_range(cred->cr_expire, expired, jiffies) &&
305 test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
306 return 0;
308 list_del_init(&cred->cr_lru);
309 number_cred_unused--;
310 if (atomic_read(&cred->cr_count) != 0)
311 continue;
313 cache_lock = &cred->cr_auth->au_credcache->lock;
314 spin_lock(cache_lock);
315 if (atomic_read(&cred->cr_count) == 0) {
316 get_rpccred(cred);
317 list_add_tail(&cred->cr_lru, free);
318 rpcauth_unhash_cred_locked(cred);
320 spin_unlock(cache_lock);
322 return (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
326 * Run memory cache shrinker.
328 static int
329 rpcauth_cache_shrinker(struct shrinker *shrink, struct shrink_control *sc)
331 LIST_HEAD(free);
332 int res;
333 int nr_to_scan = sc->nr_to_scan;
334 gfp_t gfp_mask = sc->gfp_mask;
336 if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
337 return (nr_to_scan == 0) ? 0 : -1;
338 if (list_empty(&cred_unused))
339 return 0;
340 spin_lock(&rpc_credcache_lock);
341 res = rpcauth_prune_expired(&free, nr_to_scan);
342 spin_unlock(&rpc_credcache_lock);
343 rpcauth_destroy_credlist(&free);
344 return res;
348 * Look up a process' credentials in the authentication cache
350 struct rpc_cred *
351 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
352 int flags)
354 LIST_HEAD(free);
355 struct rpc_cred_cache *cache = auth->au_credcache;
356 struct hlist_node *pos;
357 struct rpc_cred *cred = NULL,
358 *entry, *new;
359 unsigned int nr;
361 nr = hash_long(acred->uid, cache->hashbits);
363 rcu_read_lock();
364 hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
365 if (!entry->cr_ops->crmatch(acred, entry, flags))
366 continue;
367 spin_lock(&cache->lock);
368 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
369 spin_unlock(&cache->lock);
370 continue;
372 cred = get_rpccred(entry);
373 spin_unlock(&cache->lock);
374 break;
376 rcu_read_unlock();
378 if (cred != NULL)
379 goto found;
381 new = auth->au_ops->crcreate(auth, acred, flags);
382 if (IS_ERR(new)) {
383 cred = new;
384 goto out;
387 spin_lock(&cache->lock);
388 hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
389 if (!entry->cr_ops->crmatch(acred, entry, flags))
390 continue;
391 cred = get_rpccred(entry);
392 break;
394 if (cred == NULL) {
395 cred = new;
396 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
397 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
398 } else
399 list_add_tail(&new->cr_lru, &free);
400 spin_unlock(&cache->lock);
401 found:
402 if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
403 cred->cr_ops->cr_init != NULL &&
404 !(flags & RPCAUTH_LOOKUP_NEW)) {
405 int res = cred->cr_ops->cr_init(auth, cred);
406 if (res < 0) {
407 put_rpccred(cred);
408 cred = ERR_PTR(res);
411 rpcauth_destroy_credlist(&free);
412 out:
413 return cred;
415 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
417 struct rpc_cred *
418 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
420 struct auth_cred acred;
421 struct rpc_cred *ret;
422 const struct cred *cred = current_cred();
424 dprintk("RPC: looking up %s cred\n",
425 auth->au_ops->au_name);
427 memset(&acred, 0, sizeof(acred));
428 acred.uid = cred->fsuid;
429 acred.gid = cred->fsgid;
430 acred.group_info = get_group_info(((struct cred *)cred)->group_info);
432 ret = auth->au_ops->lookup_cred(auth, &acred, flags);
433 put_group_info(acred.group_info);
434 return ret;
437 void
438 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
439 struct rpc_auth *auth, const struct rpc_credops *ops)
441 INIT_HLIST_NODE(&cred->cr_hash);
442 INIT_LIST_HEAD(&cred->cr_lru);
443 atomic_set(&cred->cr_count, 1);
444 cred->cr_auth = auth;
445 cred->cr_ops = ops;
446 cred->cr_expire = jiffies;
447 #ifdef RPC_DEBUG
448 cred->cr_magic = RPCAUTH_CRED_MAGIC;
449 #endif
450 cred->cr_uid = acred->uid;
452 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
454 struct rpc_cred *
455 rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags)
457 dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
458 cred->cr_auth->au_ops->au_name, cred);
459 return get_rpccred(cred);
461 EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
463 static struct rpc_cred *
464 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
466 struct rpc_auth *auth = task->tk_client->cl_auth;
467 struct auth_cred acred = {
468 .uid = 0,
469 .gid = 0,
472 dprintk("RPC: %5u looking up %s cred\n",
473 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
474 return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
477 static struct rpc_cred *
478 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
480 struct rpc_auth *auth = task->tk_client->cl_auth;
482 dprintk("RPC: %5u looking up %s cred\n",
483 task->tk_pid, auth->au_ops->au_name);
484 return rpcauth_lookupcred(auth, lookupflags);
487 static int
488 rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
490 struct rpc_rqst *req = task->tk_rqstp;
491 struct rpc_cred *new;
492 int lookupflags = 0;
494 if (flags & RPC_TASK_ASYNC)
495 lookupflags |= RPCAUTH_LOOKUP_NEW;
496 if (cred != NULL)
497 new = cred->cr_ops->crbind(task, cred, lookupflags);
498 else if (flags & RPC_TASK_ROOTCREDS)
499 new = rpcauth_bind_root_cred(task, lookupflags);
500 else
501 new = rpcauth_bind_new_cred(task, lookupflags);
502 if (IS_ERR(new))
503 return PTR_ERR(new);
504 if (req->rq_cred != NULL)
505 put_rpccred(req->rq_cred);
506 req->rq_cred = new;
507 return 0;
510 void
511 put_rpccred(struct rpc_cred *cred)
513 /* Fast path for unhashed credentials */
514 if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) {
515 if (atomic_dec_and_test(&cred->cr_count))
516 cred->cr_ops->crdestroy(cred);
517 return;
520 if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
521 return;
522 if (!list_empty(&cred->cr_lru)) {
523 number_cred_unused--;
524 list_del_init(&cred->cr_lru);
526 if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
527 if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
528 cred->cr_expire = jiffies;
529 list_add_tail(&cred->cr_lru, &cred_unused);
530 number_cred_unused++;
531 goto out_nodestroy;
533 if (!rpcauth_unhash_cred(cred)) {
534 /* We were hashed and someone looked us up... */
535 goto out_nodestroy;
538 spin_unlock(&rpc_credcache_lock);
539 cred->cr_ops->crdestroy(cred);
540 return;
541 out_nodestroy:
542 spin_unlock(&rpc_credcache_lock);
544 EXPORT_SYMBOL_GPL(put_rpccred);
546 __be32 *
547 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
549 struct rpc_cred *cred = task->tk_rqstp->rq_cred;
551 dprintk("RPC: %5u marshaling %s cred %p\n",
552 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
554 return cred->cr_ops->crmarshal(task, p);
557 __be32 *
558 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
560 struct rpc_cred *cred = task->tk_rqstp->rq_cred;
562 dprintk("RPC: %5u validating %s cred %p\n",
563 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
565 return cred->cr_ops->crvalidate(task, p);
568 static void rpcauth_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
569 __be32 *data, void *obj)
571 struct xdr_stream xdr;
573 xdr_init_encode(&xdr, &rqstp->rq_snd_buf, data);
574 encode(rqstp, &xdr, obj);
578 rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp,
579 __be32 *data, void *obj)
581 struct rpc_cred *cred = task->tk_rqstp->rq_cred;
583 dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
584 task->tk_pid, cred->cr_ops->cr_name, cred);
585 if (cred->cr_ops->crwrap_req)
586 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
587 /* By default, we encode the arguments normally. */
588 rpcauth_wrap_req_encode(encode, rqstp, data, obj);
589 return 0;
592 static int
593 rpcauth_unwrap_req_decode(kxdrdproc_t decode, struct rpc_rqst *rqstp,
594 __be32 *data, void *obj)
596 struct xdr_stream xdr;
598 xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, data);
599 return decode(rqstp, &xdr, obj);
603 rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp,
604 __be32 *data, void *obj)
606 struct rpc_cred *cred = task->tk_rqstp->rq_cred;
608 dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
609 task->tk_pid, cred->cr_ops->cr_name, cred);
610 if (cred->cr_ops->crunwrap_resp)
611 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
612 data, obj);
613 /* By default, we decode the arguments normally. */
614 return rpcauth_unwrap_req_decode(decode, rqstp, data, obj);
618 rpcauth_refreshcred(struct rpc_task *task)
620 struct rpc_cred *cred;
621 int err;
623 cred = task->tk_rqstp->rq_cred;
624 if (cred == NULL) {
625 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
626 if (err < 0)
627 goto out;
628 cred = task->tk_rqstp->rq_cred;
630 dprintk("RPC: %5u refreshing %s cred %p\n",
631 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
633 err = cred->cr_ops->crrefresh(task);
634 out:
635 if (err < 0)
636 task->tk_status = err;
637 return err;
640 void
641 rpcauth_invalcred(struct rpc_task *task)
643 struct rpc_cred *cred = task->tk_rqstp->rq_cred;
645 dprintk("RPC: %5u invalidating %s cred %p\n",
646 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
647 if (cred)
648 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
652 rpcauth_uptodatecred(struct rpc_task *task)
654 struct rpc_cred *cred = task->tk_rqstp->rq_cred;
656 return cred == NULL ||
657 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
660 static struct shrinker rpc_cred_shrinker = {
661 .shrink = rpcauth_cache_shrinker,
662 .seeks = DEFAULT_SEEKS,
665 int __init rpcauth_init_module(void)
667 int err;
669 err = rpc_init_authunix();
670 if (err < 0)
671 goto out1;
672 err = rpc_init_generic_auth();
673 if (err < 0)
674 goto out2;
675 register_shrinker(&rpc_cred_shrinker);
676 return 0;
677 out2:
678 rpc_destroy_authunix();
679 out1:
680 return err;
683 void rpcauth_remove_module(void)
685 rpc_destroy_authunix();
686 rpc_destroy_generic_auth();
687 unregister_shrinker(&rpc_cred_shrinker);