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 #define RPC_CREDCACHE_DEFAULT_HASHBITS  (4)
  23 struct rpc_cred_cache {
  24         struct hlist_head       *hashtable;
  25         unsigned int            hashbits;
  26         spinlock_t              lock;
  27 };
  28
  29 static unsigned int auth_hashbits = RPC_CREDCACHE_DEFAULT_HASHBITS;
  30
  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 */
  36 };
  37
  38 static LIST_HEAD(cred_unused);
  39 static unsigned long number_cred_unused;
  40
  41 #define MAX_HASHTABLE_BITS (10)
  42 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
  43 {
  44         unsigned long num;
  45         unsigned int nbits;
  46         int ret;
  47
  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;
  62 }
  63
  64 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
  65 {
  66         unsigned int nbits;
  67
  68         nbits = *(unsigned int *)kp->arg;
  69         return sprintf(buffer, "%u", 1U << nbits);
  70 }
  71
  72 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
  73
  74 static struct kernel_param_ops param_ops_hashtbl_sz = {
  75         .set = param_set_hashtbl_sz,
  76         .get = param_get_hashtbl_sz,
  77 };
  78
  79 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
  80 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
  81
  82 static u32
  83 pseudoflavor_to_flavor(u32 flavor) {
  84         if (flavor >= RPC_AUTH_MAXFLAVOR)
  85                 return RPC_AUTH_GSS;
  86         return flavor;
  87 }
  88
  89 int
  90 rpcauth_register(const struct rpc_authops *ops)
  91 {
  92         rpc_authflavor_t flavor;
  93         int ret = -EPERM;
  94
  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;
 101         }
 102         spin_unlock(&rpc_authflavor_lock);
 103         return ret;
 104 }
 105 EXPORT_SYMBOL_GPL(rpcauth_register);
 106
 107 int
 108 rpcauth_unregister(const struct rpc_authops *ops)
 109 {
 110         rpc_authflavor_t flavor;
 111         int ret = -EPERM;
 112
 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;
 119         }
 120         spin_unlock(&rpc_authflavor_lock);
 121         return ret;
 122 }
 123 EXPORT_SYMBOL_GPL(rpcauth_unregister);
 124
 125 struct rpc_auth *
 126 rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
 127 {
 128         struct rpc_auth         *auth;
 129         const struct rpc_authops *ops;
 130         u32                     flavor = pseudoflavor_to_flavor(pseudoflavor);
 131
 132         auth = ERR_PTR(-EINVAL);
 133         if (flavor >= RPC_AUTH_MAXFLAVOR)
 134                 goto out;
 135
 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;
 143         }
 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;
 152
 153 out:
 154         return auth;
 155 }
 156 EXPORT_SYMBOL_GPL(rpcauth_create);
 157
 158 void
 159 rpcauth_release(struct rpc_auth *auth)
 160 {
 161         if (!atomic_dec_and_test(&auth->au_count))
 162                 return;
 163         auth->au_ops->destroy(auth);
 164 }
 165
 166 static DEFINE_SPINLOCK(rpc_credcache_lock);
 167
 168 static void
 169 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
 170 {
 171         hlist_del_rcu(&cred->cr_hash);
 172         smp_mb__before_clear_bit();
 173         clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 174 }
 175
 176 static int
 177 rpcauth_unhash_cred(struct rpc_cred *cred)
 178 {
 179         spinlock_t *cache_lock;
 180         int ret;
 181
 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;
 189 }
 190
 191 /*
 192  * Initialize RPC credential cache
 193  */
 194 int
 195 rpcauth_init_credcache(struct rpc_auth *auth)
 196 {
 197         struct rpc_cred_cache *new;
 198         unsigned int hashsize;
 199
 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;
 215 }
 216 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
 217
 218 /*
 219  * Destroy a list of credentials
 220  */
 221 static inline
 222 void rpcauth_destroy_credlist(struct list_head *head)
 223 {
 224         struct rpc_cred *cred;
 225
 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);
 230         }
 231 }
 232
 233 /*
 234  * Clear the RPC credential cache, and delete those credentials
 235  * that are not referenced.
 236  */
 237 void
 238 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
 239 {
 240         LIST_HEAD(free);
 241         struct hlist_head *head;
 242         struct rpc_cred *cred;
 243         unsigned int hashsize = 1U << cache->hashbits;
 244         int             i;
 245
 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--;
 256                         }
 257                         list_add_tail(&cred->cr_lru, &free);
 258                         rpcauth_unhash_cred_locked(cred);
 259                 }
 260         }
 261         spin_unlock(&cache->lock);
 262         spin_unlock(&rpc_credcache_lock);
 263         rpcauth_destroy_credlist(&free);
 264 }
 265
 266 /*
 267  * Destroy the RPC credential cache
 268  */
 269 void
 270 rpcauth_destroy_credcache(struct rpc_auth *auth)
 271 {
 272         struct rpc_cred_cache *cache = auth->au_credcache;
 273
 274         if (cache) {
 275                 auth->au_credcache = NULL;
 276                 rpcauth_clear_credcache(cache);
 277                 kfree(cache->hashtable);
 278                 kfree(cache);
 279         }
 280 }
 281 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
 282
 283
 284 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
 285
 286 /*
 287  * Remove stale credentials. Avoid sleeping inside the loop.
 288  */
 289 static int
 290 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
 291 {
 292         spinlock_t *cache_lock;
 293         struct rpc_cred *cred, *next;
 294         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
 295
 296         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
 297
 298                 if (nr_to_scan-- == 0)
 299                         break;
 300                 /*
 301                  * Enforce a 60 second garbage collection moratorium
 302                  * Note that the cred_unused list must be time-ordered.
 303                  */
 304                 if (time_in_range(cred->cr_expire, expired, jiffies) &&
 305                     test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
 306                         return 0;
 307
 308                 list_del_init(&cred->cr_lru);
 309                 number_cred_unused--;
 310                 if (atomic_read(&cred->cr_count) != 0)
 311                         continue;
 312
 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);
 319                 }
 320                 spin_unlock(cache_lock);
 321         }
 322         return (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
 323 }
 324
 325 /*
 326  * Run memory cache shrinker.
 327  */
 328 static int
 329 rpcauth_cache_shrinker(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
 330 {
 331         LIST_HEAD(free);
 332         int res;
 333
 334         if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
 335                 return (nr_to_scan == 0) ? 0 : -1;
 336         if (list_empty(&cred_unused))
 337                 return 0;
 338         spin_lock(&rpc_credcache_lock);
 339         res = rpcauth_prune_expired(&free, nr_to_scan);
 340         spin_unlock(&rpc_credcache_lock);
 341         rpcauth_destroy_credlist(&free);
 342         return res;
 343 }
 344
 345 /*
 346  * Look up a process' credentials in the authentication cache
 347  */
 348 struct rpc_cred *
 349 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 350                 int flags)
 351 {
 352         LIST_HEAD(free);
 353         struct rpc_cred_cache *cache = auth->au_credcache;
 354         struct hlist_node *pos;
 355         struct rpc_cred *cred = NULL,
 356                         *entry, *new;
 357         unsigned int nr;
 358
 359         nr = hash_long(acred->uid, cache->hashbits);
 360
 361         rcu_read_lock();
 362         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
 363                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 364                         continue;
 365                 spin_lock(&cache->lock);
 366                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
 367                         spin_unlock(&cache->lock);
 368                         continue;
 369                 }
 370                 cred = get_rpccred(entry);
 371                 spin_unlock(&cache->lock);
 372                 break;
 373         }
 374         rcu_read_unlock();
 375
 376         if (cred != NULL)
 377                 goto found;
 378
 379         new = auth->au_ops->crcreate(auth, acred, flags);
 380         if (IS_ERR(new)) {
 381                 cred = new;
 382                 goto out;
 383         }
 384
 385         spin_lock(&cache->lock);
 386         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
 387                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 388                         continue;
 389                 cred = get_rpccred(entry);
 390                 break;
 391         }
 392         if (cred == NULL) {
 393                 cred = new;
 394                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 395                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
 396         } else
 397                 list_add_tail(&new->cr_lru, &free);
 398         spin_unlock(&cache->lock);
 399 found:
 400         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
 401             cred->cr_ops->cr_init != NULL &&
 402             !(flags & RPCAUTH_LOOKUP_NEW)) {
 403                 int res = cred->cr_ops->cr_init(auth, cred);
 404                 if (res < 0) {
 405                         put_rpccred(cred);
 406                         cred = ERR_PTR(res);
 407                 }
 408         }
 409         rpcauth_destroy_credlist(&free);
 410 out:
 411         return cred;
 412 }
 413 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
 414
 415 struct rpc_cred *
 416 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 417 {
 418         struct auth_cred acred;
 419         struct rpc_cred *ret;
 420         const struct cred *cred = current_cred();
 421
 422         dprintk("RPC:       looking up %s cred\n",
 423                 auth->au_ops->au_name);
 424
 425         memset(&acred, 0, sizeof(acred));
 426         acred.uid = cred->fsuid;
 427         acred.gid = cred->fsgid;
 428         acred.group_info = get_group_info(((struct cred *)cred)->group_info);
 429
 430         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 431         put_group_info(acred.group_info);
 432         return ret;
 433 }
 434
 435 void
 436 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 437                   struct rpc_auth *auth, const struct rpc_credops *ops)
 438 {
 439         INIT_HLIST_NODE(&cred->cr_hash);
 440         INIT_LIST_HEAD(&cred->cr_lru);
 441         atomic_set(&cred->cr_count, 1);
 442         cred->cr_auth = auth;
 443         cred->cr_ops = ops;
 444         cred->cr_expire = jiffies;
 445 #ifdef RPC_DEBUG
 446         cred->cr_magic = RPCAUTH_CRED_MAGIC;
 447 #endif
 448         cred->cr_uid = acred->uid;
 449 }
 450 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 451
 452 struct rpc_cred *
 453 rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags)
 454 {
 455         dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
 456                         cred->cr_auth->au_ops->au_name, cred);
 457         return get_rpccred(cred);
 458 }
 459 EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
 460
 461 static struct rpc_cred *
 462 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
 463 {
 464         struct rpc_auth *auth = task->tk_client->cl_auth;
 465         struct auth_cred acred = {
 466                 .uid = 0,
 467                 .gid = 0,
 468         };
 469
 470         dprintk("RPC: %5u looking up %s cred\n",
 471                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
 472         return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 473 }
 474
 475 static struct rpc_cred *
 476 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
 477 {
 478         struct rpc_auth *auth = task->tk_client->cl_auth;
 479
 480         dprintk("RPC: %5u looking up %s cred\n",
 481                 task->tk_pid, auth->au_ops->au_name);
 482         return rpcauth_lookupcred(auth, lookupflags);
 483 }
 484
 485 static int
 486 rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
 487 {
 488         struct rpc_rqst *req = task->tk_rqstp;
 489         struct rpc_cred *new;
 490         int lookupflags = 0;
 491
 492         if (flags & RPC_TASK_ASYNC)
 493                 lookupflags |= RPCAUTH_LOOKUP_NEW;
 494         if (cred != NULL)
 495                 new = cred->cr_ops->crbind(task, cred, lookupflags);
 496         else if (flags & RPC_TASK_ROOTCREDS)
 497                 new = rpcauth_bind_root_cred(task, lookupflags);
 498         else
 499                 new = rpcauth_bind_new_cred(task, lookupflags);
 500         if (IS_ERR(new))
 501                 return PTR_ERR(new);
 502         if (req->rq_cred != NULL)
 503                 put_rpccred(req->rq_cred);
 504         req->rq_cred = new;
 505         return 0;
 506 }
 507
 508 void
 509 put_rpccred(struct rpc_cred *cred)
 510 {
 511         /* Fast path for unhashed credentials */
 512         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) {
 513                 if (atomic_dec_and_test(&cred->cr_count))
 514                         cred->cr_ops->crdestroy(cred);
 515                 return;
 516         }
 517
 518         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
 519                 return;
 520         if (!list_empty(&cred->cr_lru)) {
 521                 number_cred_unused--;
 522                 list_del_init(&cred->cr_lru);
 523         }
 524         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
 525                 if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
 526                         cred->cr_expire = jiffies;
 527                         list_add_tail(&cred->cr_lru, &cred_unused);
 528                         number_cred_unused++;
 529                         goto out_nodestroy;
 530                 }
 531                 if (!rpcauth_unhash_cred(cred)) {
 532                         /* We were hashed and someone looked us up... */
 533                         goto out_nodestroy;
 534                 }
 535         }
 536         spin_unlock(&rpc_credcache_lock);
 537         cred->cr_ops->crdestroy(cred);
 538         return;
 539 out_nodestroy:
 540         spin_unlock(&rpc_credcache_lock);
 541 }
 542 EXPORT_SYMBOL_GPL(put_rpccred);
 543
 544 __be32 *
 545 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
 546 {
 547         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 548
 549         dprintk("RPC: %5u marshaling %s cred %p\n",
 550                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 551
 552         return cred->cr_ops->crmarshal(task, p);
 553 }
 554
 555 __be32 *
 556 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
 557 {
 558         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 559
 560         dprintk("RPC: %5u validating %s cred %p\n",
 561                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 562
 563         return cred->cr_ops->crvalidate(task, p);
 564 }
 565
 566 int
 567 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
 568                 __be32 *data, void *obj)
 569 {
 570         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 571
 572         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
 573                         task->tk_pid, cred->cr_ops->cr_name, cred);
 574         if (cred->cr_ops->crwrap_req)
 575                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
 576         /* By default, we encode the arguments normally. */
 577         return encode(rqstp, data, obj);
 578 }
 579
 580 int
 581 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
 582                 __be32 *data, void *obj)
 583 {
 584         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 585
 586         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
 587                         task->tk_pid, cred->cr_ops->cr_name, cred);
 588         if (cred->cr_ops->crunwrap_resp)
 589                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
 590                                                    data, obj);
 591         /* By default, we decode the arguments normally. */
 592         return decode(rqstp, data, obj);
 593 }
 594
 595 int
 596 rpcauth_refreshcred(struct rpc_task *task)
 597 {
 598         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 599         int err;
 600
 601         cred = task->tk_rqstp->rq_cred;
 602         if (cred == NULL) {
 603                 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
 604                 if (err < 0)
 605                         goto out;
 606                 cred = task->tk_rqstp->rq_cred;
 607         };
 608         dprintk("RPC: %5u refreshing %s cred %p\n",
 609                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 610
 611         err = cred->cr_ops->crrefresh(task);
 612 out:
 613         if (err < 0)
 614                 task->tk_status = err;
 615         return err;
 616 }
 617
 618 void
 619 rpcauth_invalcred(struct rpc_task *task)
 620 {
 621         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 622
 623         dprintk("RPC: %5u invalidating %s cred %p\n",
 624                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 625         if (cred)
 626                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 627 }
 628
 629 int
 630 rpcauth_uptodatecred(struct rpc_task *task)
 631 {
 632         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 633
 634         return cred == NULL ||
 635                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 636 }
 637
 638 static struct shrinker rpc_cred_shrinker = {
 639         .shrink = rpcauth_cache_shrinker,
 640         .seeks = DEFAULT_SEEKS,
 641 };
 642
 643 int __init rpcauth_init_module(void)
 644 {
 645         int err;
 646
 647         err = rpc_init_authunix();
 648         if (err < 0)
 649                 goto out1;
 650         err = rpc_init_generic_auth();
 651         if (err < 0)
 652                 goto out2;
 653         register_shrinker(&rpc_cred_shrinker);
 654         return 0;
 655 out2:
 656         rpc_destroy_authunix();
 657 out1:
 658         return err;
 659 }
 660
 661 void __exit rpcauth_remove_module(void)
 662 {
 663         rpc_destroy_authunix();
 664         rpc_destroy_generic_auth();
 665         unregister_shrinker(&rpc_cred_shrinker);
 666 }