/net/sunrpc/auth.c
C | 597 lines | 485 code | 78 blank | 34 comment | 69 complexity | 88d64c9dea99ce1688bda55cc3dfaebb MD5 | raw file
Possible License(s): CC-BY-SA-3.0, GPL-2.0, LGPL-2.0, AGPL-1.0
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
22static DEFINE_SPINLOCK(rpc_authflavor_lock);
23static 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
29static LIST_HEAD(cred_unused);
30static unsigned long number_cred_unused;
31
32static u32
33pseudoflavor_to_flavor(u32 flavor) {
34 if (flavor >= RPC_AUTH_MAXFLAVOR)
35 return RPC_AUTH_GSS;
36 return flavor;
37}
38
39int
40rpcauth_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}
55EXPORT_SYMBOL_GPL(rpcauth_register);
56
57int
58rpcauth_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}
73EXPORT_SYMBOL_GPL(rpcauth_unregister);
74
75struct rpc_auth *
76rpcauth_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
103out:
104 return auth;
105}
106EXPORT_SYMBOL_GPL(rpcauth_create);
107
108void
109rpcauth_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
116static DEFINE_SPINLOCK(rpc_credcache_lock);
117
118static void
119rpcauth_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
126static int
127rpcauth_unhash_cred(struct rpc_cred *cred)
128{
129 spinlock_t *cache_lock;
130 int ret;
131
132 cache_lock = &cred->cr_auth->au_credcache->lock;
133 spin_lock(cache_lock);
134 ret = atomic_read(&cred->cr_count) == 0;
135 if (ret)
136 rpcauth_unhash_cred_locked(cred);
137 spin_unlock(cache_lock);
138 return ret;
139}
140
141/*
142 * Initialize RPC credential cache
143 */
144int
145rpcauth_init_credcache(struct rpc_auth *auth)
146{
147 struct rpc_cred_cache *new;
148 int i;
149
150 new = kmalloc(sizeof(*new), GFP_KERNEL);
151 if (!new)
152 return -ENOMEM;
153 for (i = 0; i < RPC_CREDCACHE_NR; i++)
154 INIT_HLIST_HEAD(&new->hashtable[i]);
155 spin_lock_init(&new->lock);
156 auth->au_credcache = new;
157 return 0;
158}
159EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
160
161/*
162 * Destroy a list of credentials
163 */
164static inline
165void rpcauth_destroy_credlist(struct list_head *head)
166{
167 struct rpc_cred *cred;
168
169 while (!list_empty(head)) {
170 cred = list_entry(head->next, struct rpc_cred, cr_lru);
171 list_del_init(&cred->cr_lru);
172 put_rpccred(cred);
173 }
174}
175
176/*
177 * Clear the RPC credential cache, and delete those credentials
178 * that are not referenced.
179 */
180void
181rpcauth_clear_credcache(struct rpc_cred_cache *cache)
182{
183 LIST_HEAD(free);
184 struct hlist_head *head;
185 struct rpc_cred *cred;
186 int i;
187
188 spin_lock(&rpc_credcache_lock);
189 spin_lock(&cache->lock);
190 for (i = 0; i < RPC_CREDCACHE_NR; i++) {
191 head = &cache->hashtable[i];
192 while (!hlist_empty(head)) {
193 cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
194 get_rpccred(cred);
195 if (!list_empty(&cred->cr_lru)) {
196 list_del(&cred->cr_lru);
197 number_cred_unused--;
198 }
199 list_add_tail(&cred->cr_lru, &free);
200 rpcauth_unhash_cred_locked(cred);
201 }
202 }
203 spin_unlock(&cache->lock);
204 spin_unlock(&rpc_credcache_lock);
205 rpcauth_destroy_credlist(&free);
206}
207
208/*
209 * Destroy the RPC credential cache
210 */
211void
212rpcauth_destroy_credcache(struct rpc_auth *auth)
213{
214 struct rpc_cred_cache *cache = auth->au_credcache;
215
216 if (cache) {
217 auth->au_credcache = NULL;
218 rpcauth_clear_credcache(cache);
219 kfree(cache);
220 }
221}
222EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
223
224
225#define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
226
227/*
228 * Remove stale credentials. Avoid sleeping inside the loop.
229 */
230static int
231rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
232{
233 spinlock_t *cache_lock;
234 struct rpc_cred *cred, *next;
235 unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
236
237 list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
238
239 /* Enforce a 60 second garbage collection moratorium */
240 if (time_in_range(cred->cr_expire, expired, jiffies) &&
241 test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
242 continue;
243
244 list_del_init(&cred->cr_lru);
245 number_cred_unused--;
246 if (atomic_read(&cred->cr_count) != 0)
247 continue;
248
249 cache_lock = &cred->cr_auth->au_credcache->lock;
250 spin_lock(cache_lock);
251 if (atomic_read(&cred->cr_count) == 0) {
252 get_rpccred(cred);
253 list_add_tail(&cred->cr_lru, free);
254 rpcauth_unhash_cred_locked(cred);
255 nr_to_scan--;
256 }
257 spin_unlock(cache_lock);
258 if (nr_to_scan == 0)
259 break;
260 }
261 return nr_to_scan;
262}
263
264/*
265 * Run memory cache shrinker.
266 */
267static int
268rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
269{
270 LIST_HEAD(free);
271 int res;
272
273 if (list_empty(&cred_unused))
274 return 0;
275 spin_lock(&rpc_credcache_lock);
276 nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
277 res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
278 spin_unlock(&rpc_credcache_lock);
279 rpcauth_destroy_credlist(&free);
280 return res;
281}
282
283/*
284 * Look up a process' credentials in the authentication cache
285 */
286struct rpc_cred *
287rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
288 int flags)
289{
290 LIST_HEAD(free);
291 struct rpc_cred_cache *cache = auth->au_credcache;
292 struct hlist_node *pos;
293 struct rpc_cred *cred = NULL,
294 *entry, *new;
295 unsigned int nr;
296
297 nr = hash_long(acred->uid, RPC_CREDCACHE_HASHBITS);
298
299 rcu_read_lock();
300 hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
301 if (!entry->cr_ops->crmatch(acred, entry, flags))
302 continue;
303 spin_lock(&cache->lock);
304 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
305 spin_unlock(&cache->lock);
306 continue;
307 }
308 cred = get_rpccred(entry);
309 spin_unlock(&cache->lock);
310 break;
311 }
312 rcu_read_unlock();
313
314 if (cred != NULL)
315 goto found;
316
317 new = auth->au_ops->crcreate(auth, acred, flags);
318 if (IS_ERR(new)) {
319 cred = new;
320 goto out;
321 }
322
323 spin_lock(&cache->lock);
324 hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
325 if (!entry->cr_ops->crmatch(acred, entry, flags))
326 continue;
327 cred = get_rpccred(entry);
328 break;
329 }
330 if (cred == NULL) {
331 cred = new;
332 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
333 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
334 } else
335 list_add_tail(&new->cr_lru, &free);
336 spin_unlock(&cache->lock);
337found:
338 if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
339 cred->cr_ops->cr_init != NULL &&
340 !(flags & RPCAUTH_LOOKUP_NEW)) {
341 int res = cred->cr_ops->cr_init(auth, cred);
342 if (res < 0) {
343 put_rpccred(cred);
344 cred = ERR_PTR(res);
345 }
346 }
347 rpcauth_destroy_credlist(&free);
348out:
349 return cred;
350}
351EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
352
353struct rpc_cred *
354rpcauth_lookupcred(struct rpc_auth *auth, int flags)
355{
356 struct auth_cred acred;
357 struct rpc_cred *ret;
358 const struct cred *cred = current_cred();
359
360 dprintk("RPC: looking up %s cred\n",
361 auth->au_ops->au_name);
362
363 memset(&acred, 0, sizeof(acred));
364 acred.uid = cred->fsuid;
365 acred.gid = cred->fsgid;
366 acred.group_info = get_group_info(((struct cred *)cred)->group_info);
367
368 ret = auth->au_ops->lookup_cred(auth, &acred, flags);
369 put_group_info(acred.group_info);
370 return ret;
371}
372
373void
374rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
375 struct rpc_auth *auth, const struct rpc_credops *ops)
376{
377 INIT_HLIST_NODE(&cred->cr_hash);
378 INIT_LIST_HEAD(&cred->cr_lru);
379 atomic_set(&cred->cr_count, 1);
380 cred->cr_auth = auth;
381 cred->cr_ops = ops;
382 cred->cr_expire = jiffies;
383#ifdef RPC_DEBUG
384 cred->cr_magic = RPCAUTH_CRED_MAGIC;
385#endif
386 cred->cr_uid = acred->uid;
387}
388EXPORT_SYMBOL_GPL(rpcauth_init_cred);
389
390void
391rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags)
392{
393 task->tk_msg.rpc_cred = get_rpccred(cred);
394 dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
395 cred->cr_auth->au_ops->au_name, cred);
396}
397EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
398
399static void
400rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
401{
402 struct rpc_auth *auth = task->tk_client->cl_auth;
403 struct auth_cred acred = {
404 .uid = 0,
405 .gid = 0,
406 };
407 struct rpc_cred *ret;
408
409 dprintk("RPC: %5u looking up %s cred\n",
410 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
411 ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
412 if (!IS_ERR(ret))
413 task->tk_msg.rpc_cred = ret;
414 else
415 task->tk_status = PTR_ERR(ret);
416}
417
418static void
419rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
420{
421 struct rpc_auth *auth = task->tk_client->cl_auth;
422 struct rpc_cred *ret;
423
424 dprintk("RPC: %5u looking up %s cred\n",
425 task->tk_pid, auth->au_ops->au_name);
426 ret = rpcauth_lookupcred(auth, lookupflags);
427 if (!IS_ERR(ret))
428 task->tk_msg.rpc_cred = ret;
429 else
430 task->tk_status = PTR_ERR(ret);
431}
432
433void
434rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
435{
436 int lookupflags = 0;
437
438 if (flags & RPC_TASK_ASYNC)
439 lookupflags |= RPCAUTH_LOOKUP_NEW;
440 if (cred != NULL)
441 cred->cr_ops->crbind(task, cred, lookupflags);
442 else if (flags & RPC_TASK_ROOTCREDS)
443 rpcauth_bind_root_cred(task, lookupflags);
444 else
445 rpcauth_bind_new_cred(task, lookupflags);
446}
447
448void
449put_rpccred(struct rpc_cred *cred)
450{
451 /* Fast path for unhashed credentials */
452 if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) {
453 if (atomic_dec_and_test(&cred->cr_count))
454 cred->cr_ops->crdestroy(cred);
455 return;
456 }
457
458 if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
459 return;
460 if (!list_empty(&cred->cr_lru)) {
461 number_cred_unused--;
462 list_del_init(&cred->cr_lru);
463 }
464 if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
465 if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
466 cred->cr_expire = jiffies;
467 list_add_tail(&cred->cr_lru, &cred_unused);
468 number_cred_unused++;
469 goto out_nodestroy;
470 }
471 if (!rpcauth_unhash_cred(cred)) {
472 /* We were hashed and someone looked us up... */
473 goto out_nodestroy;
474 }
475 }
476 spin_unlock(&rpc_credcache_lock);
477 cred->cr_ops->crdestroy(cred);
478 return;
479out_nodestroy:
480 spin_unlock(&rpc_credcache_lock);
481}
482EXPORT_SYMBOL_GPL(put_rpccred);
483
484void
485rpcauth_unbindcred(struct rpc_task *task)
486{
487 struct rpc_cred *cred = task->tk_msg.rpc_cred;
488
489 dprintk("RPC: %5u releasing %s cred %p\n",
490 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
491
492 put_rpccred(cred);
493 task->tk_msg.rpc_cred = NULL;
494}
495
496__be32 *
497rpcauth_marshcred(struct rpc_task *task, __be32 *p)
498{
499 struct rpc_cred *cred = task->tk_msg.rpc_cred;
500
501 dprintk("RPC: %5u marshaling %s cred %p\n",
502 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
503
504 return cred->cr_ops->crmarshal(task, p);
505}
506
507__be32 *
508rpcauth_checkverf(struct rpc_task *task, __be32 *p)
509{
510 struct rpc_cred *cred = task->tk_msg.rpc_cred;
511
512 dprintk("RPC: %5u validating %s cred %p\n",
513 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
514
515 return cred->cr_ops->crvalidate(task, p);
516}
517
518int
519rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
520 __be32 *data, void *obj)
521{
522 struct rpc_cred *cred = task->tk_msg.rpc_cred;
523
524 dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
525 task->tk_pid, cred->cr_ops->cr_name, cred);
526 if (cred->cr_ops->crwrap_req)
527 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
528 /* By default, we encode the arguments normally. */
529 return encode(rqstp, data, obj);
530}
531
532int
533rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
534 __be32 *data, void *obj)
535{
536 struct rpc_cred *cred = task->tk_msg.rpc_cred;
537
538 dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
539 task->tk_pid, cred->cr_ops->cr_name, cred);
540 if (cred->cr_ops->crunwrap_resp)
541 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
542 data, obj);
543 /* By default, we decode the arguments normally. */
544 return decode(rqstp, data, obj);
545}
546
547int
548rpcauth_refreshcred(struct rpc_task *task)
549{
550 struct rpc_cred *cred = task->tk_msg.rpc_cred;
551 int err;
552
553 dprintk("RPC: %5u refreshing %s cred %p\n",
554 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
555
556 err = cred->cr_ops->crrefresh(task);
557 if (err < 0)
558 task->tk_status = err;
559 return err;
560}
561
562void
563rpcauth_invalcred(struct rpc_task *task)
564{
565 struct rpc_cred *cred = task->tk_msg.rpc_cred;
566
567 dprintk("RPC: %5u invalidating %s cred %p\n",
568 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
569 if (cred)
570 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
571}
572
573int
574rpcauth_uptodatecred(struct rpc_task *task)
575{
576 struct rpc_cred *cred = task->tk_msg.rpc_cred;
577
578 return cred == NULL ||
579 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
580}
581
582static struct shrinker rpc_cred_shrinker = {
583 .shrink = rpcauth_cache_shrinker,
584 .seeks = DEFAULT_SEEKS,
585};
586
587void __init rpcauth_init_module(void)
588{
589 rpc_init_authunix();
590 rpc_init_generic_auth();
591 register_shrinker(&rpc_cred_shrinker);
592}
593
594void __exit rpcauth_remove_module(void)
595{
596 unregister_shrinker(&rpc_cred_shrinker);
597}