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 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  21 # define RPCDBG_FACILITY        RPCDBG_AUTH
  22 #endif
  23
  24 #define RPC_CREDCACHE_DEFAULT_HASHBITS  (4)
  25 struct rpc_cred_cache {
  26         struct hlist_head       *hashtable;
  27         unsigned int            hashbits;
  28         spinlock_t              lock;
  29 };
  30
  31 static unsigned int auth_hashbits = RPC_CREDCACHE_DEFAULT_HASHBITS;
  32
  33 static const struct rpc_authops __rcu *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
  34         [RPC_AUTH_NULL] = (const struct rpc_authops __force __rcu *)&authnull_ops,
  35         [RPC_AUTH_UNIX] = (const struct rpc_authops __force __rcu *)&authunix_ops,
  36         NULL,                   /* others can be loadable modules */
  37 };
  38
  39 static LIST_HEAD(cred_unused);
  40 static unsigned long number_cred_unused;
  41
  42 static struct cred machine_cred = {
  43         .usage = ATOMIC_INIT(1),
  44 #ifdef CONFIG_DEBUG_CREDENTIALS
  45         .magic = CRED_MAGIC,
  46 #endif
  47 };
  48
  49 /*
  50  * Return the machine_cred pointer to be used whenever
  51  * the a generic machine credential is needed.
  52  */
  53 const struct cred *rpc_machine_cred(void)
  54 {
  55         return &machine_cred;
  56 }
  57 EXPORT_SYMBOL_GPL(rpc_machine_cred);
  58
  59 #define MAX_HASHTABLE_BITS (14)
  60 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
  61 {
  62         unsigned long num;
  63         unsigned int nbits;
  64         int ret;
  65
  66         if (!val)
  67                 goto out_inval;
  68         ret = kstrtoul(val, 0, &num);
  69         if (ret)
  70                 goto out_inval;
  71         nbits = fls(num - 1);
  72         if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
  73                 goto out_inval;
  74         *(unsigned int *)kp->arg = nbits;
  75         return 0;
  76 out_inval:
  77         return -EINVAL;
  78 }
  79
  80 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
  81 {
  82         unsigned int nbits;
  83
  84         nbits = *(unsigned int *)kp->arg;
  85         return sprintf(buffer, "%u", 1U << nbits);
  86 }
  87
  88 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
  89
  90 static const struct kernel_param_ops param_ops_hashtbl_sz = {
  91         .set = param_set_hashtbl_sz,
  92         .get = param_get_hashtbl_sz,
  93 };
  94
  95 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
  96 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
  97
  98 static unsigned long auth_max_cred_cachesize = ULONG_MAX;
  99 module_param(auth_max_cred_cachesize, ulong, 0644);
 100 MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size");
 101
 102 static u32
 103 pseudoflavor_to_flavor(u32 flavor) {
 104         if (flavor > RPC_AUTH_MAXFLAVOR)
 105                 return RPC_AUTH_GSS;
 106         return flavor;
 107 }
 108
 109 int
 110 rpcauth_register(const struct rpc_authops *ops)
 111 {
 112         const struct rpc_authops *old;
 113         rpc_authflavor_t flavor;
 114
 115         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 116                 return -EINVAL;
 117         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], NULL, ops);
 118         if (old == NULL || old == ops)
 119                 return 0;
 120         return -EPERM;
 121 }
 122 EXPORT_SYMBOL_GPL(rpcauth_register);
 123
 124 int
 125 rpcauth_unregister(const struct rpc_authops *ops)
 126 {
 127         const struct rpc_authops *old;
 128         rpc_authflavor_t flavor;
 129
 130         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 131                 return -EINVAL;
 132
 133         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], ops, NULL);
 134         if (old == ops || old == NULL)
 135                 return 0;
 136         return -EPERM;
 137 }
 138 EXPORT_SYMBOL_GPL(rpcauth_unregister);
 139
 140 static const struct rpc_authops *
 141 rpcauth_get_authops(rpc_authflavor_t flavor)
 142 {
 143         const struct rpc_authops *ops;
 144
 145         if (flavor >= RPC_AUTH_MAXFLAVOR)
 146                 return NULL;
 147
 148         rcu_read_lock();
 149         ops = rcu_dereference(auth_flavors[flavor]);
 150         if (ops == NULL) {
 151                 rcu_read_unlock();
 152                 request_module("rpc-auth-%u", flavor);
 153                 rcu_read_lock();
 154                 ops = rcu_dereference(auth_flavors[flavor]);
 155                 if (ops == NULL)
 156                         goto out;
 157         }
 158         if (!try_module_get(ops->owner))
 159                 ops = NULL;
 160 out:
 161         rcu_read_unlock();
 162         return ops;
 163 }
 164
 165 static void
 166 rpcauth_put_authops(const struct rpc_authops *ops)
 167 {
 168         module_put(ops->owner);
 169 }
 170
 171 /**
 172  * rpcauth_get_pseudoflavor - check if security flavor is supported
 173  * @flavor: a security flavor
 174  * @info: a GSS mech OID, quality of protection, and service value
 175  *
 176  * Verifies that an appropriate kernel module is available or already loaded.
 177  * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
 178  * not supported locally.
 179  */
 180 rpc_authflavor_t
 181 rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
 182 {
 183         const struct rpc_authops *ops = rpcauth_get_authops(flavor);
 184         rpc_authflavor_t pseudoflavor;
 185
 186         if (!ops)
 187                 return RPC_AUTH_MAXFLAVOR;
 188         pseudoflavor = flavor;
 189         if (ops->info2flavor != NULL)
 190                 pseudoflavor = ops->info2flavor(info);
 191
 192         rpcauth_put_authops(ops);
 193         return pseudoflavor;
 194 }
 195 EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
 196
 197 /**
 198  * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor
 199  * @pseudoflavor: GSS pseudoflavor to match
 200  * @info: rpcsec_gss_info structure to fill in
 201  *
 202  * Returns zero and fills in "info" if pseudoflavor matches a
 203  * supported mechanism.
 204  */
 205 int
 206 rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
 207 {
 208         rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor);
 209         const struct rpc_authops *ops;
 210         int result;
 211
 212         ops = rpcauth_get_authops(flavor);
 213         if (ops == NULL)
 214                 return -ENOENT;
 215
 216         result = -ENOENT;
 217         if (ops->flavor2info != NULL)
 218                 result = ops->flavor2info(pseudoflavor, info);
 219
 220         rpcauth_put_authops(ops);
 221         return result;
 222 }
 223 EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
 224
 225 /**
 226  * rpcauth_list_flavors - discover registered flavors and pseudoflavors
 227  * @array: array to fill in
 228  * @size: size of "array"
 229  *
 230  * Returns the number of array items filled in, or a negative errno.
 231  *
 232  * The returned array is not sorted by any policy.  Callers should not
 233  * rely on the order of the items in the returned array.
 234  */
 235 int
 236 rpcauth_list_flavors(rpc_authflavor_t *array, int size)
 237 {
 238         const struct rpc_authops *ops;
 239         rpc_authflavor_t flavor, pseudos[4];
 240         int i, len, result = 0;
 241
 242         rcu_read_lock();
 243         for (flavor = 0; flavor < RPC_AUTH_MAXFLAVOR; flavor++) {
 244                 ops = rcu_dereference(auth_flavors[flavor]);
 245                 if (result >= size) {
 246                         result = -ENOMEM;
 247                         break;
 248                 }
 249
 250                 if (ops == NULL)
 251                         continue;
 252                 if (ops->list_pseudoflavors == NULL) {
 253                         array[result++] = ops->au_flavor;
 254                         continue;
 255                 }
 256                 len = ops->list_pseudoflavors(pseudos, ARRAY_SIZE(pseudos));
 257                 if (len < 0) {
 258                         result = len;
 259                         break;
 260                 }
 261                 for (i = 0; i < len; i++) {
 262                         if (result >= size) {
 263                                 result = -ENOMEM;
 264                                 break;
 265                         }
 266                         array[result++] = pseudos[i];
 267                 }
 268         }
 269         rcu_read_unlock();
 270
 271         dprintk("RPC:       %s returns %d\n", __func__, result);
 272         return result;
 273 }
 274 EXPORT_SYMBOL_GPL(rpcauth_list_flavors);
 275
 276 struct rpc_auth *
 277 rpcauth_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
 278 {
 279         struct rpc_auth *auth = ERR_PTR(-EINVAL);
 280         const struct rpc_authops *ops;
 281         u32 flavor = pseudoflavor_to_flavor(args->pseudoflavor);
 282
 283         ops = rpcauth_get_authops(flavor);
 284         if (ops == NULL)
 285                 goto out;
 286
 287         auth = ops->create(args, clnt);
 288
 289         rpcauth_put_authops(ops);
 290         if (IS_ERR(auth))
 291                 return auth;
 292         if (clnt->cl_auth)
 293                 rpcauth_release(clnt->cl_auth);
 294         clnt->cl_auth = auth;
 295
 296 out:
 297         return auth;
 298 }
 299 EXPORT_SYMBOL_GPL(rpcauth_create);
 300
 301 void
 302 rpcauth_release(struct rpc_auth *auth)
 303 {
 304         if (!refcount_dec_and_test(&auth->au_count))
 305                 return;
 306         auth->au_ops->destroy(auth);
 307 }
 308
 309 static DEFINE_SPINLOCK(rpc_credcache_lock);
 310
 311 /*
 312  * On success, the caller is responsible for freeing the reference
 313  * held by the hashtable
 314  */
 315 static bool
 316 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
 317 {
 318         if (!test_and_clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 319                 return false;
 320         hlist_del_rcu(&cred->cr_hash);
 321         return true;
 322 }
 323
 324 static bool
 325 rpcauth_unhash_cred(struct rpc_cred *cred)
 326 {
 327         spinlock_t *cache_lock;
 328         bool ret;
 329
 330         if (!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 331                 return false;
 332         cache_lock = &cred->cr_auth->au_credcache->lock;
 333         spin_lock(cache_lock);
 334         ret = rpcauth_unhash_cred_locked(cred);
 335         spin_unlock(cache_lock);
 336         return ret;
 337 }
 338
 339 /*
 340  * Initialize RPC credential cache
 341  */
 342 int
 343 rpcauth_init_credcache(struct rpc_auth *auth)
 344 {
 345         struct rpc_cred_cache *new;
 346         unsigned int hashsize;
 347
 348         new = kmalloc(sizeof(*new), GFP_KERNEL);
 349         if (!new)
 350                 goto out_nocache;
 351         new->hashbits = auth_hashbits;
 352         hashsize = 1U << new->hashbits;
 353         new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
 354         if (!new->hashtable)
 355                 goto out_nohashtbl;
 356         spin_lock_init(&new->lock);
 357         auth->au_credcache = new;
 358         return 0;
 359 out_nohashtbl:
 360         kfree(new);
 361 out_nocache:
 362         return -ENOMEM;
 363 }
 364 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
 365
 366 char *
 367 rpcauth_stringify_acceptor(struct rpc_cred *cred)
 368 {
 369         if (!cred->cr_ops->crstringify_acceptor)
 370                 return NULL;
 371         return cred->cr_ops->crstringify_acceptor(cred);
 372 }
 373 EXPORT_SYMBOL_GPL(rpcauth_stringify_acceptor);
 374
 375 /*
 376  * Destroy a list of credentials
 377  */
 378 static inline
 379 void rpcauth_destroy_credlist(struct list_head *head)
 380 {
 381         struct rpc_cred *cred;
 382
 383         while (!list_empty(head)) {
 384                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
 385                 list_del_init(&cred->cr_lru);
 386                 put_rpccred(cred);
 387         }
 388 }
 389
 390 static void
 391 rpcauth_lru_add_locked(struct rpc_cred *cred)
 392 {
 393         if (!list_empty(&cred->cr_lru))
 394                 return;
 395         number_cred_unused++;
 396         list_add_tail(&cred->cr_lru, &cred_unused);
 397 }
 398
 399 static void
 400 rpcauth_lru_add(struct rpc_cred *cred)
 401 {
 402         if (!list_empty(&cred->cr_lru))
 403                 return;
 404         spin_lock(&rpc_credcache_lock);
 405         rpcauth_lru_add_locked(cred);
 406         spin_unlock(&rpc_credcache_lock);
 407 }
 408
 409 static void
 410 rpcauth_lru_remove_locked(struct rpc_cred *cred)
 411 {
 412         if (list_empty(&cred->cr_lru))
 413                 return;
 414         number_cred_unused--;
 415         list_del_init(&cred->cr_lru);
 416 }
 417
 418 static void
 419 rpcauth_lru_remove(struct rpc_cred *cred)
 420 {
 421         if (list_empty(&cred->cr_lru))
 422                 return;
 423         spin_lock(&rpc_credcache_lock);
 424         rpcauth_lru_remove_locked(cred);
 425         spin_unlock(&rpc_credcache_lock);
 426 }
 427
 428 /*
 429  * Clear the RPC credential cache, and delete those credentials
 430  * that are not referenced.
 431  */
 432 void
 433 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
 434 {
 435         LIST_HEAD(free);
 436         struct hlist_head *head;
 437         struct rpc_cred *cred;
 438         unsigned int hashsize = 1U << cache->hashbits;
 439         int             i;
 440
 441         spin_lock(&rpc_credcache_lock);
 442         spin_lock(&cache->lock);
 443         for (i = 0; i < hashsize; i++) {
 444                 head = &cache->hashtable[i];
 445                 while (!hlist_empty(head)) {
 446                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
 447                         rpcauth_unhash_cred_locked(cred);
 448                         /* Note: We now hold a reference to cred */
 449                         rpcauth_lru_remove_locked(cred);
 450                         list_add_tail(&cred->cr_lru, &free);
 451                 }
 452         }
 453         spin_unlock(&cache->lock);
 454         spin_unlock(&rpc_credcache_lock);
 455         rpcauth_destroy_credlist(&free);
 456 }
 457
 458 /*
 459  * Destroy the RPC credential cache
 460  */
 461 void
 462 rpcauth_destroy_credcache(struct rpc_auth *auth)
 463 {
 464         struct rpc_cred_cache *cache = auth->au_credcache;
 465
 466         if (cache) {
 467                 auth->au_credcache = NULL;
 468                 rpcauth_clear_credcache(cache);
 469                 kfree(cache->hashtable);
 470                 kfree(cache);
 471         }
 472 }
 473 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
 474
 475
 476 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
 477
 478 /*
 479  * Remove stale credentials. Avoid sleeping inside the loop.
 480  */
 481 static long
 482 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
 483 {
 484         struct rpc_cred *cred, *next;
 485         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
 486         long freed = 0;
 487
 488         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
 489
 490                 if (nr_to_scan-- == 0)
 491                         break;
 492                 if (refcount_read(&cred->cr_count) > 1) {
 493                         rpcauth_lru_remove_locked(cred);
 494                         continue;
 495                 }
 496                 /*
 497                  * Enforce a 60 second garbage collection moratorium
 498                  * Note that the cred_unused list must be time-ordered.
 499                  */
 500                 if (!time_in_range(cred->cr_expire, expired, jiffies))
 501                         continue;
 502                 if (!rpcauth_unhash_cred(cred))
 503                         continue;
 504
 505                 rpcauth_lru_remove_locked(cred);
 506                 freed++;
 507                 list_add_tail(&cred->cr_lru, free);
 508         }
 509         return freed ? freed : SHRINK_STOP;
 510 }
 511
 512 static unsigned long
 513 rpcauth_cache_do_shrink(int nr_to_scan)
 514 {
 515         LIST_HEAD(free);
 516         unsigned long freed;
 517
 518         spin_lock(&rpc_credcache_lock);
 519         freed = rpcauth_prune_expired(&free, nr_to_scan);
 520         spin_unlock(&rpc_credcache_lock);
 521         rpcauth_destroy_credlist(&free);
 522
 523         return freed;
 524 }
 525
 526 /*
 527  * Run memory cache shrinker.
 528  */
 529 static unsigned long
 530 rpcauth_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 531
 532 {
 533         if ((sc->gfp_mask & GFP_KERNEL) != GFP_KERNEL)
 534                 return SHRINK_STOP;
 535
 536         /* nothing left, don't come back */
 537         if (list_empty(&cred_unused))
 538                 return SHRINK_STOP;
 539
 540         return rpcauth_cache_do_shrink(sc->nr_to_scan);
 541 }
 542
 543 static unsigned long
 544 rpcauth_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 545
 546 {
 547         return number_cred_unused * sysctl_vfs_cache_pressure / 100;
 548 }
 549
 550 static void
 551 rpcauth_cache_enforce_limit(void)
 552 {
 553         unsigned long diff;
 554         unsigned int nr_to_scan;
 555
 556         if (number_cred_unused <= auth_max_cred_cachesize)
 557                 return;
 558         diff = number_cred_unused - auth_max_cred_cachesize;
 559         nr_to_scan = 100;
 560         if (diff < nr_to_scan)
 561                 nr_to_scan = diff;
 562         rpcauth_cache_do_shrink(nr_to_scan);
 563 }
 564
 565 /*
 566  * Look up a process' credentials in the authentication cache
 567  */
 568 struct rpc_cred *
 569 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 570                 int flags, gfp_t gfp)
 571 {
 572         LIST_HEAD(free);
 573         struct rpc_cred_cache *cache = auth->au_credcache;
 574         struct rpc_cred *cred = NULL,
 575                         *entry, *new;
 576         unsigned int nr;
 577
 578         nr = auth->au_ops->hash_cred(acred, cache->hashbits);
 579
 580         rcu_read_lock();
 581         hlist_for_each_entry_rcu(entry, &cache->hashtable[nr], cr_hash) {
 582                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 583                         continue;
 584                 cred = get_rpccred(entry);
 585                 if (cred)
 586                         break;
 587         }
 588         rcu_read_unlock();
 589
 590         if (cred != NULL)
 591                 goto found;
 592
 593         new = auth->au_ops->crcreate(auth, acred, flags, gfp);
 594         if (IS_ERR(new)) {
 595                 cred = new;
 596                 goto out;
 597         }
 598
 599         spin_lock(&cache->lock);
 600         hlist_for_each_entry(entry, &cache->hashtable[nr], cr_hash) {
 601                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 602                         continue;
 603                 cred = get_rpccred(entry);
 604                 if (cred)
 605                         break;
 606         }
 607         if (cred == NULL) {
 608                 cred = new;
 609                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 610                 refcount_inc(&cred->cr_count);
 611                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
 612         } else
 613                 list_add_tail(&new->cr_lru, &free);
 614         spin_unlock(&cache->lock);
 615         rpcauth_cache_enforce_limit();
 616 found:
 617         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
 618             cred->cr_ops->cr_init != NULL &&
 619             !(flags & RPCAUTH_LOOKUP_NEW)) {
 620                 int res = cred->cr_ops->cr_init(auth, cred);
 621                 if (res < 0) {
 622                         put_rpccred(cred);
 623                         cred = ERR_PTR(res);
 624                 }
 625         }
 626         rpcauth_destroy_credlist(&free);
 627 out:
 628         return cred;
 629 }
 630 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
 631
 632 struct rpc_cred *
 633 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 634 {
 635         struct auth_cred acred;
 636         struct rpc_cred *ret;
 637         const struct cred *cred = current_cred();
 638
 639         dprintk("RPC:       looking up %s cred\n",
 640                 auth->au_ops->au_name);
 641
 642         memset(&acred, 0, sizeof(acred));
 643         acred.cred = cred;
 644         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 645         return ret;
 646 }
 647 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
 648
 649 void
 650 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 651                   struct rpc_auth *auth, const struct rpc_credops *ops)
 652 {
 653         INIT_HLIST_NODE(&cred->cr_hash);
 654         INIT_LIST_HEAD(&cred->cr_lru);
 655         refcount_set(&cred->cr_count, 1);
 656         cred->cr_auth = auth;
 657         cred->cr_flags = 0;
 658         cred->cr_ops = ops;
 659         cred->cr_expire = jiffies;
 660         cred->cr_cred = get_cred(acred->cred);
 661 }
 662 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 663
 664 static struct rpc_cred *
 665 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
 666 {
 667         struct rpc_auth *auth = task->tk_client->cl_auth;
 668         struct auth_cred acred = {
 669                 .cred = get_task_cred(&init_task),
 670         };
 671         struct rpc_cred *ret;
 672
 673         dprintk("RPC: %5u looking up %s cred\n",
 674                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
 675         ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 676         put_cred(acred.cred);
 677         return ret;
 678 }
 679
 680 static struct rpc_cred *
 681 rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags)
 682 {
 683         struct rpc_auth *auth = task->tk_client->cl_auth;
 684         struct auth_cred acred = {
 685                 .principal = task->tk_client->cl_principal,
 686                 .cred = init_task.cred,
 687         };
 688
 689         if (!acred.principal)
 690                 return NULL;
 691         dprintk("RPC: %5u looking up %s machine cred\n",
 692                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
 693         return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 694 }
 695
 696 static struct rpc_cred *
 697 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
 698 {
 699         struct rpc_auth *auth = task->tk_client->cl_auth;
 700
 701         dprintk("RPC: %5u looking up %s cred\n",
 702                 task->tk_pid, auth->au_ops->au_name);
 703         return rpcauth_lookupcred(auth, lookupflags);
 704 }
 705
 706 static int
 707 rpcauth_bindcred(struct rpc_task *task, const struct cred *cred, int flags)
 708 {
 709         struct rpc_rqst *req = task->tk_rqstp;
 710         struct rpc_cred *new = NULL;
 711         int lookupflags = 0;
 712         struct rpc_auth *auth = task->tk_client->cl_auth;
 713         struct auth_cred acred = {
 714                 .cred = cred,
 715         };
 716
 717         if (flags & RPC_TASK_ASYNC)
 718                 lookupflags |= RPCAUTH_LOOKUP_NEW;
 719         if (task->tk_op_cred)
 720                 /* Task must use exactly this rpc_cred */
 721                 new = get_rpccred(task->tk_op_cred);
 722         else if (cred != NULL && cred != &machine_cred)
 723                 new = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 724         else if (cred == &machine_cred)
 725                 new = rpcauth_bind_machine_cred(task, lookupflags);
 726
 727         /* If machine cred couldn't be bound, try a root cred */
 728         if (new)
 729                 ;
 730         else if (cred == &machine_cred || (flags & RPC_TASK_ROOTCREDS))
 731                 new = rpcauth_bind_root_cred(task, lookupflags);
 732         else if (flags & RPC_TASK_NULLCREDS)
 733                 new = authnull_ops.lookup_cred(NULL, NULL, 0);
 734         else
 735                 new = rpcauth_bind_new_cred(task, lookupflags);
 736         if (IS_ERR(new))
 737                 return PTR_ERR(new);
 738         put_rpccred(req->rq_cred);
 739         req->rq_cred = new;
 740         return 0;
 741 }
 742
 743 void
 744 put_rpccred(struct rpc_cred *cred)
 745 {
 746         if (cred == NULL)
 747                 return;
 748         rcu_read_lock();
 749         if (refcount_dec_and_test(&cred->cr_count))
 750                 goto destroy;
 751         if (refcount_read(&cred->cr_count) != 1 ||
 752             !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 753                 goto out;
 754         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
 755                 cred->cr_expire = jiffies;
 756                 rpcauth_lru_add(cred);
 757                 /* Race breaker */
 758                 if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)))
 759                         rpcauth_lru_remove(cred);
 760         } else if (rpcauth_unhash_cred(cred)) {
 761                 rpcauth_lru_remove(cred);
 762                 if (refcount_dec_and_test(&cred->cr_count))
 763                         goto destroy;
 764         }
 765 out:
 766         rcu_read_unlock();
 767         return;
 768 destroy:
 769         rcu_read_unlock();
 770         cred->cr_ops->crdestroy(cred);
 771 }
 772 EXPORT_SYMBOL_GPL(put_rpccred);
 773
 774 __be32 *
 775 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
 776 {
 777         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 778
 779         dprintk("RPC: %5u marshaling %s cred %p\n",
 780                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 781
 782         return cred->cr_ops->crmarshal(task, p);
 783 }
 784
 785 __be32 *
 786 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
 787 {
 788         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 789
 790         dprintk("RPC: %5u validating %s cred %p\n",
 791                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 792
 793         return cred->cr_ops->crvalidate(task, p);
 794 }
 795
 796 static void rpcauth_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
 797                                    __be32 *data, void *obj)
 798 {
 799         struct xdr_stream xdr;
 800
 801         xdr_init_encode(&xdr, &rqstp->rq_snd_buf, data);
 802         encode(rqstp, &xdr, obj);
 803 }
 804
 805 int
 806 rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp,
 807                 __be32 *data, void *obj)
 808 {
 809         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 810
 811         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
 812                         task->tk_pid, cred->cr_ops->cr_name, cred);
 813         if (cred->cr_ops->crwrap_req)
 814                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
 815         /* By default, we encode the arguments normally. */
 816         rpcauth_wrap_req_encode(encode, rqstp, data, obj);
 817         return 0;
 818 }
 819
 820 static int
 821 rpcauth_unwrap_req_decode(kxdrdproc_t decode, struct rpc_rqst *rqstp,
 822                           __be32 *data, void *obj)
 823 {
 824         struct xdr_stream xdr;
 825
 826         xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, data);
 827         return decode(rqstp, &xdr, obj);
 828 }
 829
 830 int
 831 rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp,
 832                 __be32 *data, void *obj)
 833 {
 834         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 835
 836         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
 837                         task->tk_pid, cred->cr_ops->cr_name, cred);
 838         if (cred->cr_ops->crunwrap_resp)
 839                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
 840                                                    data, obj);
 841         /* By default, we decode the arguments normally. */
 842         return rpcauth_unwrap_req_decode(decode, rqstp, data, obj);
 843 }
 844
 845 bool
 846 rpcauth_xmit_need_reencode(struct rpc_task *task)
 847 {
 848         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 849
 850         if (!cred || !cred->cr_ops->crneed_reencode)
 851                 return false;
 852         return cred->cr_ops->crneed_reencode(task);
 853 }
 854
 855 int
 856 rpcauth_refreshcred(struct rpc_task *task)
 857 {
 858         struct rpc_cred *cred;
 859         int err;
 860
 861         cred = task->tk_rqstp->rq_cred;
 862         if (cred == NULL) {
 863                 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
 864                 if (err < 0)
 865                         goto out;
 866                 cred = task->tk_rqstp->rq_cred;
 867         }
 868         dprintk("RPC: %5u refreshing %s cred %p\n",
 869                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 870
 871         err = cred->cr_ops->crrefresh(task);
 872 out:
 873         if (err < 0)
 874                 task->tk_status = err;
 875         return err;
 876 }
 877
 878 void
 879 rpcauth_invalcred(struct rpc_task *task)
 880 {
 881         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 882
 883         dprintk("RPC: %5u invalidating %s cred %p\n",
 884                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 885         if (cred)
 886                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 887 }
 888
 889 int
 890 rpcauth_uptodatecred(struct rpc_task *task)
 891 {
 892         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 893
 894         return cred == NULL ||
 895                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 896 }
 897
 898 static struct shrinker rpc_cred_shrinker = {
 899         .count_objects = rpcauth_cache_shrink_count,
 900         .scan_objects = rpcauth_cache_shrink_scan,
 901         .seeks = DEFAULT_SEEKS,
 902 };
 903
 904 int __init rpcauth_init_module(void)
 905 {
 906         int err;
 907
 908         err = rpc_init_authunix();
 909         if (err < 0)
 910                 goto out1;
 911         err = register_shrinker(&rpc_cred_shrinker);
 912         if (err < 0)
 913                 goto out2;
 914         return 0;
 915 out2:
 916         rpc_destroy_authunix();
 917 out1:
 918         return err;
 919 }
 920
 921 void rpcauth_remove_module(void)
 922 {
 923         rpc_destroy_authunix();
 924         unregister_shrinker(&rpc_cred_shrinker);
 925 }