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/cred.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/errno.h>
  15 #include <linux/hash.h>
  16 #include <linux/sunrpc/clnt.h>
  17 #include <linux/sunrpc/gss_api.h>
  18 #include <linux/spinlock.h>
  19
  20 #include <trace/events/sunrpc.h>
  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 const struct rpc_authops __rcu *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
  32         [RPC_AUTH_NULL] = (const struct rpc_authops __force __rcu *)&authnull_ops,
  33         [RPC_AUTH_UNIX] = (const struct rpc_authops __force __rcu *)&authunix_ops,
  34         NULL,                   /* others can be loadable modules */
  35 };
  36
  37 static LIST_HEAD(cred_unused);
  38 static unsigned long number_cred_unused;
  39
  40 static struct cred machine_cred = {
  41         .usage = ATOMIC_INIT(1),
  42 #ifdef CONFIG_DEBUG_CREDENTIALS
  43         .magic = CRED_MAGIC,
  44 #endif
  45 };
  46
  47 /*
  48  * Return the machine_cred pointer to be used whenever
  49  * the a generic machine credential is needed.
  50  */
  51 const struct cred *rpc_machine_cred(void)
  52 {
  53         return &machine_cred;
  54 }
  55 EXPORT_SYMBOL_GPL(rpc_machine_cred);
  56
  57 #define MAX_HASHTABLE_BITS (14)
  58 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
  59 {
  60         unsigned long num;
  61         unsigned int nbits;
  62         int ret;
  63
  64         if (!val)
  65                 goto out_inval;
  66         ret = kstrtoul(val, 0, &num);
  67         if (ret)
  68                 goto out_inval;
  69         nbits = fls(num - 1);
  70         if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
  71                 goto out_inval;
  72         *(unsigned int *)kp->arg = nbits;
  73         return 0;
  74 out_inval:
  75         return -EINVAL;
  76 }
  77
  78 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
  79 {
  80         unsigned int nbits;
  81
  82         nbits = *(unsigned int *)kp->arg;
  83         return sprintf(buffer, "%u", 1U << nbits);
  84 }
  85
  86 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
  87
  88 static const struct kernel_param_ops param_ops_hashtbl_sz = {
  89         .set = param_set_hashtbl_sz,
  90         .get = param_get_hashtbl_sz,
  91 };
  92
  93 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
  94 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
  95
  96 static unsigned long auth_max_cred_cachesize = ULONG_MAX;
  97 module_param(auth_max_cred_cachesize, ulong, 0644);
  98 MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size");
  99
 100 static u32
 101 pseudoflavor_to_flavor(u32 flavor) {
 102         if (flavor > RPC_AUTH_MAXFLAVOR)
 103                 return RPC_AUTH_GSS;
 104         return flavor;
 105 }
 106
 107 int
 108 rpcauth_register(const struct rpc_authops *ops)
 109 {
 110         const struct rpc_authops *old;
 111         rpc_authflavor_t flavor;
 112
 113         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 114                 return -EINVAL;
 115         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], NULL, ops);
 116         if (old == NULL || old == ops)
 117                 return 0;
 118         return -EPERM;
 119 }
 120 EXPORT_SYMBOL_GPL(rpcauth_register);
 121
 122 int
 123 rpcauth_unregister(const struct rpc_authops *ops)
 124 {
 125         const struct rpc_authops *old;
 126         rpc_authflavor_t flavor;
 127
 128         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 129                 return -EINVAL;
 130
 131         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], ops, NULL);
 132         if (old == ops || old == NULL)
 133                 return 0;
 134         return -EPERM;
 135 }
 136 EXPORT_SYMBOL_GPL(rpcauth_unregister);
 137
 138 static const struct rpc_authops *
 139 rpcauth_get_authops(rpc_authflavor_t flavor)
 140 {
 141         const struct rpc_authops *ops;
 142
 143         if (flavor >= RPC_AUTH_MAXFLAVOR)
 144                 return NULL;
 145
 146         rcu_read_lock();
 147         ops = rcu_dereference(auth_flavors[flavor]);
 148         if (ops == NULL) {
 149                 rcu_read_unlock();
 150                 request_module("rpc-auth-%u", flavor);
 151                 rcu_read_lock();
 152                 ops = rcu_dereference(auth_flavors[flavor]);
 153                 if (ops == NULL)
 154                         goto out;
 155         }
 156         if (!try_module_get(ops->owner))
 157                 ops = NULL;
 158 out:
 159         rcu_read_unlock();
 160         return ops;
 161 }
 162
 163 static void
 164 rpcauth_put_authops(const struct rpc_authops *ops)
 165 {
 166         module_put(ops->owner);
 167 }
 168
 169 /**
 170  * rpcauth_get_pseudoflavor - check if security flavor is supported
 171  * @flavor: a security flavor
 172  * @info: a GSS mech OID, quality of protection, and service value
 173  *
 174  * Verifies that an appropriate kernel module is available or already loaded.
 175  * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
 176  * not supported locally.
 177  */
 178 rpc_authflavor_t
 179 rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
 180 {
 181         const struct rpc_authops *ops = rpcauth_get_authops(flavor);
 182         rpc_authflavor_t pseudoflavor;
 183
 184         if (!ops)
 185                 return RPC_AUTH_MAXFLAVOR;
 186         pseudoflavor = flavor;
 187         if (ops->info2flavor != NULL)
 188                 pseudoflavor = ops->info2flavor(info);
 189
 190         rpcauth_put_authops(ops);
 191         return pseudoflavor;
 192 }
 193 EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
 194
 195 /**
 196  * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor
 197  * @pseudoflavor: GSS pseudoflavor to match
 198  * @info: rpcsec_gss_info structure to fill in
 199  *
 200  * Returns zero and fills in "info" if pseudoflavor matches a
 201  * supported mechanism.
 202  */
 203 int
 204 rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
 205 {
 206         rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor);
 207         const struct rpc_authops *ops;
 208         int result;
 209
 210         ops = rpcauth_get_authops(flavor);
 211         if (ops == NULL)
 212                 return -ENOENT;
 213
 214         result = -ENOENT;
 215         if (ops->flavor2info != NULL)
 216                 result = ops->flavor2info(pseudoflavor, info);
 217
 218         rpcauth_put_authops(ops);
 219         return result;
 220 }
 221 EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
 222
 223 /**
 224  * rpcauth_list_flavors - discover registered flavors and pseudoflavors
 225  * @array: array to fill in
 226  * @size: size of "array"
 227  *
 228  * Returns the number of array items filled in, or a negative errno.
 229  *
 230  * The returned array is not sorted by any policy.  Callers should not
 231  * rely on the order of the items in the returned array.
 232  */
 233 int
 234 rpcauth_list_flavors(rpc_authflavor_t *array, int size)
 235 {
 236         const struct rpc_authops *ops;
 237         rpc_authflavor_t flavor, pseudos[4];
 238         int i, len, result = 0;
 239
 240         rcu_read_lock();
 241         for (flavor = 0; flavor < RPC_AUTH_MAXFLAVOR; flavor++) {
 242                 ops = rcu_dereference(auth_flavors[flavor]);
 243                 if (result >= size) {
 244                         result = -ENOMEM;
 245                         break;
 246                 }
 247
 248                 if (ops == NULL)
 249                         continue;
 250                 if (ops->list_pseudoflavors == NULL) {
 251                         array[result++] = ops->au_flavor;
 252                         continue;
 253                 }
 254                 len = ops->list_pseudoflavors(pseudos, ARRAY_SIZE(pseudos));
 255                 if (len < 0) {
 256                         result = len;
 257                         break;
 258                 }
 259                 for (i = 0; i < len; i++) {
 260                         if (result >= size) {
 261                                 result = -ENOMEM;
 262                                 break;
 263                         }
 264                         array[result++] = pseudos[i];
 265                 }
 266         }
 267         rcu_read_unlock();
 268         return result;
 269 }
 270 EXPORT_SYMBOL_GPL(rpcauth_list_flavors);
 271
 272 struct rpc_auth *
 273 rpcauth_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
 274 {
 275         struct rpc_auth *auth = ERR_PTR(-EINVAL);
 276         const struct rpc_authops *ops;
 277         u32 flavor = pseudoflavor_to_flavor(args->pseudoflavor);
 278
 279         ops = rpcauth_get_authops(flavor);
 280         if (ops == NULL)
 281                 goto out;
 282
 283         auth = ops->create(args, clnt);
 284
 285         rpcauth_put_authops(ops);
 286         if (IS_ERR(auth))
 287                 return auth;
 288         if (clnt->cl_auth)
 289                 rpcauth_release(clnt->cl_auth);
 290         clnt->cl_auth = auth;
 291
 292 out:
 293         return auth;
 294 }
 295 EXPORT_SYMBOL_GPL(rpcauth_create);
 296
 297 void
 298 rpcauth_release(struct rpc_auth *auth)
 299 {
 300         if (!refcount_dec_and_test(&auth->au_count))
 301                 return;
 302         auth->au_ops->destroy(auth);
 303 }
 304
 305 static DEFINE_SPINLOCK(rpc_credcache_lock);
 306
 307 /*
 308  * On success, the caller is responsible for freeing the reference
 309  * held by the hashtable
 310  */
 311 static bool
 312 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
 313 {
 314         if (!test_and_clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 315                 return false;
 316         hlist_del_rcu(&cred->cr_hash);
 317         return true;
 318 }
 319
 320 static bool
 321 rpcauth_unhash_cred(struct rpc_cred *cred)
 322 {
 323         spinlock_t *cache_lock;
 324         bool ret;
 325
 326         if (!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 327                 return false;
 328         cache_lock = &cred->cr_auth->au_credcache->lock;
 329         spin_lock(cache_lock);
 330         ret = rpcauth_unhash_cred_locked(cred);
 331         spin_unlock(cache_lock);
 332         return ret;
 333 }
 334
 335 /*
 336  * Initialize RPC credential cache
 337  */
 338 int
 339 rpcauth_init_credcache(struct rpc_auth *auth)
 340 {
 341         struct rpc_cred_cache *new;
 342         unsigned int hashsize;
 343
 344         new = kmalloc(sizeof(*new), GFP_KERNEL);
 345         if (!new)
 346                 goto out_nocache;
 347         new->hashbits = auth_hashbits;
 348         hashsize = 1U << new->hashbits;
 349         new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
 350         if (!new->hashtable)
 351                 goto out_nohashtbl;
 352         spin_lock_init(&new->lock);
 353         auth->au_credcache = new;
 354         return 0;
 355 out_nohashtbl:
 356         kfree(new);
 357 out_nocache:
 358         return -ENOMEM;
 359 }
 360 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
 361
 362 char *
 363 rpcauth_stringify_acceptor(struct rpc_cred *cred)
 364 {
 365         if (!cred->cr_ops->crstringify_acceptor)
 366                 return NULL;
 367         return cred->cr_ops->crstringify_acceptor(cred);
 368 }
 369 EXPORT_SYMBOL_GPL(rpcauth_stringify_acceptor);
 370
 371 /*
 372  * Destroy a list of credentials
 373  */
 374 static inline
 375 void rpcauth_destroy_credlist(struct list_head *head)
 376 {
 377         struct rpc_cred *cred;
 378
 379         while (!list_empty(head)) {
 380                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
 381                 list_del_init(&cred->cr_lru);
 382                 put_rpccred(cred);
 383         }
 384 }
 385
 386 static void
 387 rpcauth_lru_add_locked(struct rpc_cred *cred)
 388 {
 389         if (!list_empty(&cred->cr_lru))
 390                 return;
 391         number_cred_unused++;
 392         list_add_tail(&cred->cr_lru, &cred_unused);
 393 }
 394
 395 static void
 396 rpcauth_lru_add(struct rpc_cred *cred)
 397 {
 398         if (!list_empty(&cred->cr_lru))
 399                 return;
 400         spin_lock(&rpc_credcache_lock);
 401         rpcauth_lru_add_locked(cred);
 402         spin_unlock(&rpc_credcache_lock);
 403 }
 404
 405 static void
 406 rpcauth_lru_remove_locked(struct rpc_cred *cred)
 407 {
 408         if (list_empty(&cred->cr_lru))
 409                 return;
 410         number_cred_unused--;
 411         list_del_init(&cred->cr_lru);
 412 }
 413
 414 static void
 415 rpcauth_lru_remove(struct rpc_cred *cred)
 416 {
 417         if (list_empty(&cred->cr_lru))
 418                 return;
 419         spin_lock(&rpc_credcache_lock);
 420         rpcauth_lru_remove_locked(cred);
 421         spin_unlock(&rpc_credcache_lock);
 422 }
 423
 424 /*
 425  * Clear the RPC credential cache, and delete those credentials
 426  * that are not referenced.
 427  */
 428 void
 429 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
 430 {
 431         LIST_HEAD(free);
 432         struct hlist_head *head;
 433         struct rpc_cred *cred;
 434         unsigned int hashsize = 1U << cache->hashbits;
 435         int             i;
 436
 437         spin_lock(&rpc_credcache_lock);
 438         spin_lock(&cache->lock);
 439         for (i = 0; i < hashsize; i++) {
 440                 head = &cache->hashtable[i];
 441                 while (!hlist_empty(head)) {
 442                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
 443                         rpcauth_unhash_cred_locked(cred);
 444                         /* Note: We now hold a reference to cred */
 445                         rpcauth_lru_remove_locked(cred);
 446                         list_add_tail(&cred->cr_lru, &free);
 447                 }
 448         }
 449         spin_unlock(&cache->lock);
 450         spin_unlock(&rpc_credcache_lock);
 451         rpcauth_destroy_credlist(&free);
 452 }
 453
 454 /*
 455  * Destroy the RPC credential cache
 456  */
 457 void
 458 rpcauth_destroy_credcache(struct rpc_auth *auth)
 459 {
 460         struct rpc_cred_cache *cache = auth->au_credcache;
 461
 462         if (cache) {
 463                 auth->au_credcache = NULL;
 464                 rpcauth_clear_credcache(cache);
 465                 kfree(cache->hashtable);
 466                 kfree(cache);
 467         }
 468 }
 469 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
 470
 471
 472 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
 473
 474 /*
 475  * Remove stale credentials. Avoid sleeping inside the loop.
 476  */
 477 static long
 478 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
 479 {
 480         struct rpc_cred *cred, *next;
 481         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
 482         long freed = 0;
 483
 484         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
 485
 486                 if (nr_to_scan-- == 0)
 487                         break;
 488                 if (refcount_read(&cred->cr_count) > 1) {
 489                         rpcauth_lru_remove_locked(cred);
 490                         continue;
 491                 }
 492                 /*
 493                  * Enforce a 60 second garbage collection moratorium
 494                  * Note that the cred_unused list must be time-ordered.
 495                  */
 496                 if (!time_in_range(cred->cr_expire, expired, jiffies))
 497                         continue;
 498                 if (!rpcauth_unhash_cred(cred))
 499                         continue;
 500
 501                 rpcauth_lru_remove_locked(cred);
 502                 freed++;
 503                 list_add_tail(&cred->cr_lru, free);
 504         }
 505         return freed ? freed : SHRINK_STOP;
 506 }
 507
 508 static unsigned long
 509 rpcauth_cache_do_shrink(int nr_to_scan)
 510 {
 511         LIST_HEAD(free);
 512         unsigned long freed;
 513
 514         spin_lock(&rpc_credcache_lock);
 515         freed = rpcauth_prune_expired(&free, nr_to_scan);
 516         spin_unlock(&rpc_credcache_lock);
 517         rpcauth_destroy_credlist(&free);
 518
 519         return freed;
 520 }
 521
 522 /*
 523  * Run memory cache shrinker.
 524  */
 525 static unsigned long
 526 rpcauth_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 527
 528 {
 529         if ((sc->gfp_mask & GFP_KERNEL) != GFP_KERNEL)
 530                 return SHRINK_STOP;
 531
 532         /* nothing left, don't come back */
 533         if (list_empty(&cred_unused))
 534                 return SHRINK_STOP;
 535
 536         return rpcauth_cache_do_shrink(sc->nr_to_scan);
 537 }
 538
 539 static unsigned long
 540 rpcauth_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 541
 542 {
 543         return number_cred_unused * sysctl_vfs_cache_pressure / 100;
 544 }
 545
 546 static void
 547 rpcauth_cache_enforce_limit(void)
 548 {
 549         unsigned long diff;
 550         unsigned int nr_to_scan;
 551
 552         if (number_cred_unused <= auth_max_cred_cachesize)
 553                 return;
 554         diff = number_cred_unused - auth_max_cred_cachesize;
 555         nr_to_scan = 100;
 556         if (diff < nr_to_scan)
 557                 nr_to_scan = diff;
 558         rpcauth_cache_do_shrink(nr_to_scan);
 559 }
 560
 561 /*
 562  * Look up a process' credentials in the authentication cache
 563  */
 564 struct rpc_cred *
 565 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 566                 int flags, gfp_t gfp)
 567 {
 568         LIST_HEAD(free);
 569         struct rpc_cred_cache *cache = auth->au_credcache;
 570         struct rpc_cred *cred = NULL,
 571                         *entry, *new;
 572         unsigned int nr;
 573
 574         nr = auth->au_ops->hash_cred(acred, cache->hashbits);
 575
 576         rcu_read_lock();
 577         hlist_for_each_entry_rcu(entry, &cache->hashtable[nr], cr_hash) {
 578                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 579                         continue;
 580                 cred = get_rpccred(entry);
 581                 if (cred)
 582                         break;
 583         }
 584         rcu_read_unlock();
 585
 586         if (cred != NULL)
 587                 goto found;
 588
 589         new = auth->au_ops->crcreate(auth, acred, flags, gfp);
 590         if (IS_ERR(new)) {
 591                 cred = new;
 592                 goto out;
 593         }
 594
 595         spin_lock(&cache->lock);
 596         hlist_for_each_entry(entry, &cache->hashtable[nr], cr_hash) {
 597                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 598                         continue;
 599                 cred = get_rpccred(entry);
 600                 if (cred)
 601                         break;
 602         }
 603         if (cred == NULL) {
 604                 cred = new;
 605                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 606                 refcount_inc(&cred->cr_count);
 607                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
 608         } else
 609                 list_add_tail(&new->cr_lru, &free);
 610         spin_unlock(&cache->lock);
 611         rpcauth_cache_enforce_limit();
 612 found:
 613         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
 614             cred->cr_ops->cr_init != NULL &&
 615             !(flags & RPCAUTH_LOOKUP_NEW)) {
 616                 int res = cred->cr_ops->cr_init(auth, cred);
 617                 if (res < 0) {
 618                         put_rpccred(cred);
 619                         cred = ERR_PTR(res);
 620                 }
 621         }
 622         rpcauth_destroy_credlist(&free);
 623 out:
 624         return cred;
 625 }
 626 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
 627
 628 struct rpc_cred *
 629 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 630 {
 631         struct auth_cred acred;
 632         struct rpc_cred *ret;
 633         const struct cred *cred = current_cred();
 634
 635         memset(&acred, 0, sizeof(acred));
 636         acred.cred = cred;
 637         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 638         return ret;
 639 }
 640 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
 641
 642 void
 643 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 644                   struct rpc_auth *auth, const struct rpc_credops *ops)
 645 {
 646         INIT_HLIST_NODE(&cred->cr_hash);
 647         INIT_LIST_HEAD(&cred->cr_lru);
 648         refcount_set(&cred->cr_count, 1);
 649         cred->cr_auth = auth;
 650         cred->cr_flags = 0;
 651         cred->cr_ops = ops;
 652         cred->cr_expire = jiffies;
 653         cred->cr_cred = get_cred(acred->cred);
 654 }
 655 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 656
 657 static struct rpc_cred *
 658 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
 659 {
 660         struct rpc_auth *auth = task->tk_client->cl_auth;
 661         struct auth_cred acred = {
 662                 .cred = get_task_cred(&init_task),
 663         };
 664         struct rpc_cred *ret;
 665
 666         ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 667         put_cred(acred.cred);
 668         return ret;
 669 }
 670
 671 static struct rpc_cred *
 672 rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags)
 673 {
 674         struct rpc_auth *auth = task->tk_client->cl_auth;
 675         struct auth_cred acred = {
 676                 .principal = task->tk_client->cl_principal,
 677                 .cred = init_task.cred,
 678         };
 679
 680         if (!acred.principal)
 681                 return NULL;
 682         return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 683 }
 684
 685 static struct rpc_cred *
 686 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
 687 {
 688         struct rpc_auth *auth = task->tk_client->cl_auth;
 689
 690         return rpcauth_lookupcred(auth, lookupflags);
 691 }
 692
 693 static int
 694 rpcauth_bindcred(struct rpc_task *task, const struct cred *cred, int flags)
 695 {
 696         struct rpc_rqst *req = task->tk_rqstp;
 697         struct rpc_cred *new = NULL;
 698         int lookupflags = 0;
 699         struct rpc_auth *auth = task->tk_client->cl_auth;
 700         struct auth_cred acred = {
 701                 .cred = cred,
 702         };
 703
 704         if (flags & RPC_TASK_ASYNC)
 705                 lookupflags |= RPCAUTH_LOOKUP_NEW;
 706         if (task->tk_op_cred)
 707                 /* Task must use exactly this rpc_cred */
 708                 new = get_rpccred(task->tk_op_cred);
 709         else if (cred != NULL && cred != &machine_cred)
 710                 new = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 711         else if (cred == &machine_cred)
 712                 new = rpcauth_bind_machine_cred(task, lookupflags);
 713
 714         /* If machine cred couldn't be bound, try a root cred */
 715         if (new)
 716                 ;
 717         else if (cred == &machine_cred || (flags & RPC_TASK_ROOTCREDS))
 718                 new = rpcauth_bind_root_cred(task, lookupflags);
 719         else if (flags & RPC_TASK_NULLCREDS)
 720                 new = authnull_ops.lookup_cred(NULL, NULL, 0);
 721         else
 722                 new = rpcauth_bind_new_cred(task, lookupflags);
 723         if (IS_ERR(new))
 724                 return PTR_ERR(new);
 725         put_rpccred(req->rq_cred);
 726         req->rq_cred = new;
 727         return 0;
 728 }
 729
 730 void
 731 put_rpccred(struct rpc_cred *cred)
 732 {
 733         if (cred == NULL)
 734                 return;
 735         rcu_read_lock();
 736         if (refcount_dec_and_test(&cred->cr_count))
 737                 goto destroy;
 738         if (refcount_read(&cred->cr_count) != 1 ||
 739             !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 740                 goto out;
 741         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
 742                 cred->cr_expire = jiffies;
 743                 rpcauth_lru_add(cred);
 744                 /* Race breaker */
 745                 if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)))
 746                         rpcauth_lru_remove(cred);
 747         } else if (rpcauth_unhash_cred(cred)) {
 748                 rpcauth_lru_remove(cred);
 749                 if (refcount_dec_and_test(&cred->cr_count))
 750                         goto destroy;
 751         }
 752 out:
 753         rcu_read_unlock();
 754         return;
 755 destroy:
 756         rcu_read_unlock();
 757         cred->cr_ops->crdestroy(cred);
 758 }
 759 EXPORT_SYMBOL_GPL(put_rpccred);
 760
 761 /**
 762  * rpcauth_marshcred - Append RPC credential to end of @xdr
 763  * @task: controlling RPC task
 764  * @xdr: xdr_stream containing initial portion of RPC Call header
 765  *
 766  * On success, an appropriate verifier is added to @xdr, @xdr is
 767  * updated to point past the verifier, and zero is returned.
 768  * Otherwise, @xdr is in an undefined state and a negative errno
 769  * is returned.
 770  */
 771 int rpcauth_marshcred(struct rpc_task *task, struct xdr_stream *xdr)
 772 {
 773         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 774
 775         return ops->crmarshal(task, xdr);
 776 }
 777
 778 /**
 779  * rpcauth_wrap_req_encode - XDR encode the RPC procedure
 780  * @task: controlling RPC task
 781  * @xdr: stream where on-the-wire bytes are to be marshalled
 782  *
 783  * On success, @xdr contains the encoded and wrapped message.
 784  * Otherwise, @xdr is in an undefined state.
 785  */
 786 int rpcauth_wrap_req_encode(struct rpc_task *task, struct xdr_stream *xdr)
 787 {
 788         kxdreproc_t encode = task->tk_msg.rpc_proc->p_encode;
 789
 790         encode(task->tk_rqstp, xdr, task->tk_msg.rpc_argp);
 791         return 0;
 792 }
 793 EXPORT_SYMBOL_GPL(rpcauth_wrap_req_encode);
 794
 795 /**
 796  * rpcauth_wrap_req - XDR encode and wrap the RPC procedure
 797  * @task: controlling RPC task
 798  * @xdr: stream where on-the-wire bytes are to be marshalled
 799  *
 800  * On success, @xdr contains the encoded and wrapped message,
 801  * and zero is returned. Otherwise, @xdr is in an undefined
 802  * state and a negative errno is returned.
 803  */
 804 int rpcauth_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
 805 {
 806         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 807
 808         return ops->crwrap_req(task, xdr);
 809 }
 810
 811 /**
 812  * rpcauth_checkverf - Validate verifier in RPC Reply header
 813  * @task: controlling RPC task
 814  * @xdr: xdr_stream containing RPC Reply header
 815  *
 816  * On success, @xdr is updated to point past the verifier and
 817  * zero is returned. Otherwise, @xdr is in an undefined state
 818  * and a negative errno is returned.
 819  */
 820 int
 821 rpcauth_checkverf(struct rpc_task *task, struct xdr_stream *xdr)
 822 {
 823         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 824
 825         return ops->crvalidate(task, xdr);
 826 }
 827
 828 /**
 829  * rpcauth_unwrap_resp_decode - Invoke XDR decode function
 830  * @task: controlling RPC task
 831  * @xdr: stream where the Reply message resides
 832  *
 833  * Returns zero on success; otherwise a negative errno is returned.
 834  */
 835 int
 836 rpcauth_unwrap_resp_decode(struct rpc_task *task, struct xdr_stream *xdr)
 837 {
 838         kxdrdproc_t decode = task->tk_msg.rpc_proc->p_decode;
 839
 840         return decode(task->tk_rqstp, xdr, task->tk_msg.rpc_resp);
 841 }
 842 EXPORT_SYMBOL_GPL(rpcauth_unwrap_resp_decode);
 843
 844 /**
 845  * rpcauth_unwrap_resp - Invoke unwrap and decode function for the cred
 846  * @task: controlling RPC task
 847  * @xdr: stream where the Reply message resides
 848  *
 849  * Returns zero on success; otherwise a negative errno is returned.
 850  */
 851 int
 852 rpcauth_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr)
 853 {
 854         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 855
 856         return ops->crunwrap_resp(task, xdr);
 857 }
 858
 859 bool
 860 rpcauth_xmit_need_reencode(struct rpc_task *task)
 861 {
 862         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 863
 864         if (!cred || !cred->cr_ops->crneed_reencode)
 865                 return false;
 866         return cred->cr_ops->crneed_reencode(task);
 867 }
 868
 869 int
 870 rpcauth_refreshcred(struct rpc_task *task)
 871 {
 872         struct rpc_cred *cred;
 873         int err;
 874
 875         cred = task->tk_rqstp->rq_cred;
 876         if (cred == NULL) {
 877                 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
 878                 if (err < 0)
 879                         goto out;
 880                 cred = task->tk_rqstp->rq_cred;
 881         }
 882
 883         err = cred->cr_ops->crrefresh(task);
 884 out:
 885         if (err < 0)
 886                 task->tk_status = err;
 887         return err;
 888 }
 889
 890 void
 891 rpcauth_invalcred(struct rpc_task *task)
 892 {
 893         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 894
 895         if (cred)
 896                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 897 }
 898
 899 int
 900 rpcauth_uptodatecred(struct rpc_task *task)
 901 {
 902         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 903
 904         return cred == NULL ||
 905                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 906 }
 907
 908 static struct shrinker rpc_cred_shrinker = {
 909         .count_objects = rpcauth_cache_shrink_count,
 910         .scan_objects = rpcauth_cache_shrink_scan,
 911         .seeks = DEFAULT_SEEKS,
 912 };
 913
 914 int __init rpcauth_init_module(void)
 915 {
 916         int err;
 917
 918         err = rpc_init_authunix();
 919         if (err < 0)
 920                 goto out1;
 921         err = register_shrinker(&rpc_cred_shrinker);
 922         if (err < 0)
 923                 goto out2;
 924         return 0;
 925 out2:
 926         rpc_destroy_authunix();
 927 out1:
 928         return err;
 929 }
 930
 931 void rpcauth_remove_module(void)
 932 {
 933         rpc_destroy_authunix();
 934         unregister_shrinker(&rpc_cred_shrinker);
 935 }