net/sunrpc/auth.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/net/sunrpc/auth.c
   4  *
   5  * Generic RPC client authentication API.
   6  *
   7  * Copyright (C) 1996, Olaf Kirch <[email protected]>
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/sched.h>
  12 #include <linux/cred.h>
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/errno.h>
  16 #include <linux/hash.h>
  17 #include <linux/sunrpc/clnt.h>
  18 #include <linux/sunrpc/gss_api.h>
  19 #include <linux/spinlock.h>
  20
  21 #include <trace/events/sunrpc.h>
  22
  23 #define RPC_CREDCACHE_DEFAULT_HASHBITS  (4)
  24 struct rpc_cred_cache {
  25         struct hlist_head       *hashtable;
  26         unsigned int            hashbits;
  27         spinlock_t              lock;
  28 };
  29
  30 static unsigned int auth_hashbits = RPC_CREDCACHE_DEFAULT_HASHBITS;
  31
  32 static const struct rpc_authops __rcu *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
  33         [RPC_AUTH_NULL] = (const struct rpc_authops __force __rcu *)&authnull_ops,
  34         [RPC_AUTH_UNIX] = (const struct rpc_authops __force __rcu *)&authunix_ops,
  35         NULL,                   /* others can be loadable modules */
  36 };
  37
  38 static LIST_HEAD(cred_unused);
  39 static unsigned long number_cred_unused;
  40
  41 static struct cred machine_cred = {
  42         .usage = ATOMIC_INIT(1),
  43 #ifdef CONFIG_DEBUG_CREDENTIALS
  44         .magic = CRED_MAGIC,
  45 #endif
  46 };
  47
  48 /*
  49  * Return the machine_cred pointer to be used whenever
  50  * the a generic machine credential is needed.
  51  */
  52 const struct cred *rpc_machine_cred(void)
  53 {
  54         return &machine_cred;
  55 }
  56 EXPORT_SYMBOL_GPL(rpc_machine_cred);
  57
  58 #define MAX_HASHTABLE_BITS (14)
  59 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
  60 {
  61         unsigned long num;
  62         unsigned int nbits;
  63         int ret;
  64
  65         if (!val)
  66                 goto out_inval;
  67         ret = kstrtoul(val, 0, &num);
  68         if (ret)
  69                 goto out_inval;
  70         nbits = fls(num - 1);
  71         if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
  72                 goto out_inval;
  73         *(unsigned int *)kp->arg = nbits;
  74         return 0;
  75 out_inval:
  76         return -EINVAL;
  77 }
  78
  79 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
  80 {
  81         unsigned int nbits;
  82
  83         nbits = *(unsigned int *)kp->arg;
  84         return sprintf(buffer, "%u", 1U << nbits);
  85 }
  86
  87 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
  88
  89 static const struct kernel_param_ops param_ops_hashtbl_sz = {
  90         .set = param_set_hashtbl_sz,
  91         .get = param_get_hashtbl_sz,
  92 };
  93
  94 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
  95 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
  96
  97 static unsigned long auth_max_cred_cachesize = ULONG_MAX;
  98 module_param(auth_max_cred_cachesize, ulong, 0644);
  99 MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size");
 100
 101 static u32
 102 pseudoflavor_to_flavor(u32 flavor) {
 103         if (flavor > RPC_AUTH_MAXFLAVOR)
 104                 return RPC_AUTH_GSS;
 105         return flavor;
 106 }
 107
 108 int
 109 rpcauth_register(const struct rpc_authops *ops)
 110 {
 111         const struct rpc_authops *old;
 112         rpc_authflavor_t flavor;
 113
 114         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 115                 return -EINVAL;
 116         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], NULL, ops);
 117         if (old == NULL || old == ops)
 118                 return 0;
 119         return -EPERM;
 120 }
 121 EXPORT_SYMBOL_GPL(rpcauth_register);
 122
 123 int
 124 rpcauth_unregister(const struct rpc_authops *ops)
 125 {
 126         const struct rpc_authops *old;
 127         rpc_authflavor_t flavor;
 128
 129         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 130                 return -EINVAL;
 131
 132         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], ops, NULL);
 133         if (old == ops || old == NULL)
 134                 return 0;
 135         return -EPERM;
 136 }
 137 EXPORT_SYMBOL_GPL(rpcauth_unregister);
 138
 139 static const struct rpc_authops *
 140 rpcauth_get_authops(rpc_authflavor_t flavor)
 141 {
 142         const struct rpc_authops *ops;
 143
 144         if (flavor >= RPC_AUTH_MAXFLAVOR)
 145                 return NULL;
 146
 147         rcu_read_lock();
 148         ops = rcu_dereference(auth_flavors[flavor]);
 149         if (ops == NULL) {
 150                 rcu_read_unlock();
 151                 request_module("rpc-auth-%u", flavor);
 152                 rcu_read_lock();
 153                 ops = rcu_dereference(auth_flavors[flavor]);
 154                 if (ops == NULL)
 155                         goto out;
 156         }
 157         if (!try_module_get(ops->owner))
 158                 ops = NULL;
 159 out:
 160         rcu_read_unlock();
 161         return ops;
 162 }
 163
 164 static void
 165 rpcauth_put_authops(const struct rpc_authops *ops)
 166 {
 167         module_put(ops->owner);
 168 }
 169
 170 /**
 171  * rpcauth_get_pseudoflavor - check if security flavor is supported
 172  * @flavor: a security flavor
 173  * @info: a GSS mech OID, quality of protection, and service value
 174  *
 175  * Verifies that an appropriate kernel module is available or already loaded.
 176  * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
 177  * not supported locally.
 178  */
 179 rpc_authflavor_t
 180 rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
 181 {
 182         const struct rpc_authops *ops = rpcauth_get_authops(flavor);
 183         rpc_authflavor_t pseudoflavor;
 184
 185         if (!ops)
 186                 return RPC_AUTH_MAXFLAVOR;
 187         pseudoflavor = flavor;
 188         if (ops->info2flavor != NULL)
 189                 pseudoflavor = ops->info2flavor(info);
 190
 191         rpcauth_put_authops(ops);
 192         return pseudoflavor;
 193 }
 194 EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
 195
 196 /**
 197  * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor
 198  * @pseudoflavor: GSS pseudoflavor to match
 199  * @info: rpcsec_gss_info structure to fill in
 200  *
 201  * Returns zero and fills in "info" if pseudoflavor matches a
 202  * supported mechanism.
 203  */
 204 int
 205 rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
 206 {
 207         rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor);
 208         const struct rpc_authops *ops;
 209         int result;
 210
 211         ops = rpcauth_get_authops(flavor);
 212         if (ops == NULL)
 213                 return -ENOENT;
 214
 215         result = -ENOENT;
 216         if (ops->flavor2info != NULL)
 217                 result = ops->flavor2info(pseudoflavor, info);
 218
 219         rpcauth_put_authops(ops);
 220         return result;
 221 }
 222 EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
 223
 224 /**
 225  * rpcauth_list_flavors - discover registered flavors and pseudoflavors
 226  * @array: array to fill in
 227  * @size: size of "array"
 228  *
 229  * Returns the number of array items filled in, or a negative errno.
 230  *
 231  * The returned array is not sorted by any policy.  Callers should not
 232  * rely on the order of the items in the returned array.
 233  */
 234 int
 235 rpcauth_list_flavors(rpc_authflavor_t *array, int size)
 236 {
 237         const struct rpc_authops *ops;
 238         rpc_authflavor_t flavor, pseudos[4];
 239         int i, len, result = 0;
 240
 241         rcu_read_lock();
 242         for (flavor = 0; flavor < RPC_AUTH_MAXFLAVOR; flavor++) {
 243                 ops = rcu_dereference(auth_flavors[flavor]);
 244                 if (result >= size) {
 245                         result = -ENOMEM;
 246                         break;
 247                 }
 248
 249                 if (ops == NULL)
 250                         continue;
 251                 if (ops->list_pseudoflavors == NULL) {
 252                         array[result++] = ops->au_flavor;
 253                         continue;
 254                 }
 255                 len = ops->list_pseudoflavors(pseudos, ARRAY_SIZE(pseudos));
 256                 if (len < 0) {
 257                         result = len;
 258                         break;
 259                 }
 260                 for (i = 0; i < len; i++) {
 261                         if (result >= size) {
 262                                 result = -ENOMEM;
 263                                 break;
 264                         }
 265                         array[result++] = pseudos[i];
 266                 }
 267         }
 268         rcu_read_unlock();
 269         return result;
 270 }
 271 EXPORT_SYMBOL_GPL(rpcauth_list_flavors);
 272
 273 struct rpc_auth *
 274 rpcauth_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
 275 {
 276         struct rpc_auth *auth = ERR_PTR(-EINVAL);
 277         const struct rpc_authops *ops;
 278         u32 flavor = pseudoflavor_to_flavor(args->pseudoflavor);
 279
 280         ops = rpcauth_get_authops(flavor);
 281         if (ops == NULL)
 282                 goto out;
 283
 284         auth = ops->create(args, clnt);
 285
 286         rpcauth_put_authops(ops);
 287         if (IS_ERR(auth))
 288                 return auth;
 289         if (clnt->cl_auth)
 290                 rpcauth_release(clnt->cl_auth);
 291         clnt->cl_auth = auth;
 292
 293 out:
 294         return auth;
 295 }
 296 EXPORT_SYMBOL_GPL(rpcauth_create);
 297
 298 void
 299 rpcauth_release(struct rpc_auth *auth)
 300 {
 301         if (!refcount_dec_and_test(&auth->au_count))
 302                 return;
 303         auth->au_ops->destroy(auth);
 304 }
 305
 306 static DEFINE_SPINLOCK(rpc_credcache_lock);
 307
 308 /*
 309  * On success, the caller is responsible for freeing the reference
 310  * held by the hashtable
 311  */
 312 static bool
 313 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
 314 {
 315         if (!test_and_clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 316                 return false;
 317         hlist_del_rcu(&cred->cr_hash);
 318         return true;
 319 }
 320
 321 static bool
 322 rpcauth_unhash_cred(struct rpc_cred *cred)
 323 {
 324         spinlock_t *cache_lock;
 325         bool ret;
 326
 327         if (!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 328                 return false;
 329         cache_lock = &cred->cr_auth->au_credcache->lock;
 330         spin_lock(cache_lock);
 331         ret = rpcauth_unhash_cred_locked(cred);
 332         spin_unlock(cache_lock);
 333         return ret;
 334 }
 335
 336 /*
 337  * Initialize RPC credential cache
 338  */
 339 int
 340 rpcauth_init_credcache(struct rpc_auth *auth)
 341 {
 342         struct rpc_cred_cache *new;
 343         unsigned int hashsize;
 344
 345         new = kmalloc(sizeof(*new), GFP_KERNEL);
 346         if (!new)
 347                 goto out_nocache;
 348         new->hashbits = auth_hashbits;
 349         hashsize = 1U << new->hashbits;
 350         new->hashtable = kcalloc(hashsize, sizeof(new->hashtable[0]), GFP_KERNEL);
 351         if (!new->hashtable)
 352                 goto out_nohashtbl;
 353         spin_lock_init(&new->lock);
 354         auth->au_credcache = new;
 355         return 0;
 356 out_nohashtbl:
 357         kfree(new);
 358 out_nocache:
 359         return -ENOMEM;
 360 }
 361 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
 362
 363 char *
 364 rpcauth_stringify_acceptor(struct rpc_cred *cred)
 365 {
 366         if (!cred->cr_ops->crstringify_acceptor)
 367                 return NULL;
 368         return cred->cr_ops->crstringify_acceptor(cred);
 369 }
 370 EXPORT_SYMBOL_GPL(rpcauth_stringify_acceptor);
 371
 372 /*
 373  * Destroy a list of credentials
 374  */
 375 static inline
 376 void rpcauth_destroy_credlist(struct list_head *head)
 377 {
 378         struct rpc_cred *cred;
 379
 380         while (!list_empty(head)) {
 381                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
 382                 list_del_init(&cred->cr_lru);
 383                 put_rpccred(cred);
 384         }
 385 }
 386
 387 static void
 388 rpcauth_lru_add_locked(struct rpc_cred *cred)
 389 {
 390         if (!list_empty(&cred->cr_lru))
 391                 return;
 392         number_cred_unused++;
 393         list_add_tail(&cred->cr_lru, &cred_unused);
 394 }
 395
 396 static void
 397 rpcauth_lru_add(struct rpc_cred *cred)
 398 {
 399         if (!list_empty(&cred->cr_lru))
 400                 return;
 401         spin_lock(&rpc_credcache_lock);
 402         rpcauth_lru_add_locked(cred);
 403         spin_unlock(&rpc_credcache_lock);
 404 }
 405
 406 static void
 407 rpcauth_lru_remove_locked(struct rpc_cred *cred)
 408 {
 409         if (list_empty(&cred->cr_lru))
 410                 return;
 411         number_cred_unused--;
 412         list_del_init(&cred->cr_lru);
 413 }
 414
 415 static void
 416 rpcauth_lru_remove(struct rpc_cred *cred)
 417 {
 418         if (list_empty(&cred->cr_lru))
 419                 return;
 420         spin_lock(&rpc_credcache_lock);
 421         rpcauth_lru_remove_locked(cred);
 422         spin_unlock(&rpc_credcache_lock);
 423 }
 424
 425 /*
 426  * Clear the RPC credential cache, and delete those credentials
 427  * that are not referenced.
 428  */
 429 void
 430 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
 431 {
 432         LIST_HEAD(free);
 433         struct hlist_head *head;
 434         struct rpc_cred *cred;
 435         unsigned int hashsize = 1U << cache->hashbits;
 436         int             i;
 437
 438         spin_lock(&rpc_credcache_lock);
 439         spin_lock(&cache->lock);
 440         for (i = 0; i < hashsize; i++) {
 441                 head = &cache->hashtable[i];
 442                 while (!hlist_empty(head)) {
 443                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
 444                         rpcauth_unhash_cred_locked(cred);
 445                         /* Note: We now hold a reference to cred */
 446                         rpcauth_lru_remove_locked(cred);
 447                         list_add_tail(&cred->cr_lru, &free);
 448                 }
 449         }
 450         spin_unlock(&cache->lock);
 451         spin_unlock(&rpc_credcache_lock);
 452         rpcauth_destroy_credlist(&free);
 453 }
 454
 455 /*
 456  * Destroy the RPC credential cache
 457  */
 458 void
 459 rpcauth_destroy_credcache(struct rpc_auth *auth)
 460 {
 461         struct rpc_cred_cache *cache = auth->au_credcache;
 462
 463         if (cache) {
 464                 auth->au_credcache = NULL;
 465                 rpcauth_clear_credcache(cache);
 466                 kfree(cache->hashtable);
 467                 kfree(cache);
 468         }
 469 }
 470 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
 471
 472
 473 #define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
 474
 475 /*
 476  * Remove stale credentials. Avoid sleeping inside the loop.
 477  */
 478 static long
 479 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
 480 {
 481         struct rpc_cred *cred, *next;
 482         unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
 483         long freed = 0;
 484
 485         list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
 486
 487                 if (nr_to_scan-- == 0)
 488                         break;
 489                 if (refcount_read(&cred->cr_count) > 1) {
 490                         rpcauth_lru_remove_locked(cred);
 491                         continue;
 492                 }
 493                 /*
 494                  * Enforce a 60 second garbage collection moratorium
 495                  * Note that the cred_unused list must be time-ordered.
 496                  */
 497                 if (!time_in_range(cred->cr_expire, expired, jiffies))
 498                         continue;
 499                 if (!rpcauth_unhash_cred(cred))
 500                         continue;
 501
 502                 rpcauth_lru_remove_locked(cred);
 503                 freed++;
 504                 list_add_tail(&cred->cr_lru, free);
 505         }
 506         return freed ? freed : SHRINK_STOP;
 507 }
 508
 509 static unsigned long
 510 rpcauth_cache_do_shrink(int nr_to_scan)
 511 {
 512         LIST_HEAD(free);
 513         unsigned long freed;
 514
 515         spin_lock(&rpc_credcache_lock);
 516         freed = rpcauth_prune_expired(&free, nr_to_scan);
 517         spin_unlock(&rpc_credcache_lock);
 518         rpcauth_destroy_credlist(&free);
 519
 520         return freed;
 521 }
 522
 523 /*
 524  * Run memory cache shrinker.
 525  */
 526 static unsigned long
 527 rpcauth_cache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 528
 529 {
 530         if ((sc->gfp_mask & GFP_KERNEL) != GFP_KERNEL)
 531                 return SHRINK_STOP;
 532
 533         /* nothing left, don't come back */
 534         if (list_empty(&cred_unused))
 535                 return SHRINK_STOP;
 536
 537         return rpcauth_cache_do_shrink(sc->nr_to_scan);
 538 }
 539
 540 static unsigned long
 541 rpcauth_cache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 542
 543 {
 544         return number_cred_unused * sysctl_vfs_cache_pressure / 100;
 545 }
 546
 547 static void
 548 rpcauth_cache_enforce_limit(void)
 549 {
 550         unsigned long diff;
 551         unsigned int nr_to_scan;
 552
 553         if (number_cred_unused <= auth_max_cred_cachesize)
 554                 return;
 555         diff = number_cred_unused - auth_max_cred_cachesize;
 556         nr_to_scan = 100;
 557         if (diff < nr_to_scan)
 558                 nr_to_scan = diff;
 559         rpcauth_cache_do_shrink(nr_to_scan);
 560 }
 561
 562 /*
 563  * Look up a process' credentials in the authentication cache
 564  */
 565 struct rpc_cred *
 566 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 567                 int flags, gfp_t gfp)
 568 {
 569         LIST_HEAD(free);
 570         struct rpc_cred_cache *cache = auth->au_credcache;
 571         struct rpc_cred *cred = NULL,
 572                         *entry, *new;
 573         unsigned int nr;
 574
 575         nr = auth->au_ops->hash_cred(acred, cache->hashbits);
 576
 577         rcu_read_lock();
 578         hlist_for_each_entry_rcu(entry, &cache->hashtable[nr], cr_hash) {
 579                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 580                         continue;
 581                 cred = get_rpccred(entry);
 582                 if (cred)
 583                         break;
 584         }
 585         rcu_read_unlock();
 586
 587         if (cred != NULL)
 588                 goto found;
 589
 590         new = auth->au_ops->crcreate(auth, acred, flags, gfp);
 591         if (IS_ERR(new)) {
 592                 cred = new;
 593                 goto out;
 594         }
 595
 596         spin_lock(&cache->lock);
 597         hlist_for_each_entry(entry, &cache->hashtable[nr], cr_hash) {
 598                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 599                         continue;
 600                 cred = get_rpccred(entry);
 601                 if (cred)
 602                         break;
 603         }
 604         if (cred == NULL) {
 605                 cred = new;
 606                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 607                 refcount_inc(&cred->cr_count);
 608                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
 609         } else
 610                 list_add_tail(&new->cr_lru, &free);
 611         spin_unlock(&cache->lock);
 612         rpcauth_cache_enforce_limit();
 613 found:
 614         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
 615             cred->cr_ops->cr_init != NULL &&
 616             !(flags & RPCAUTH_LOOKUP_NEW)) {
 617                 int res = cred->cr_ops->cr_init(auth, cred);
 618                 if (res < 0) {
 619                         put_rpccred(cred);
 620                         cred = ERR_PTR(res);
 621                 }
 622         }
 623         rpcauth_destroy_credlist(&free);
 624 out:
 625         return cred;
 626 }
 627 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
 628
 629 struct rpc_cred *
 630 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 631 {
 632         struct auth_cred acred;
 633         struct rpc_cred *ret;
 634         const struct cred *cred = current_cred();
 635
 636         memset(&acred, 0, sizeof(acred));
 637         acred.cred = cred;
 638         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 639         return ret;
 640 }
 641 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
 642
 643 void
 644 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 645                   struct rpc_auth *auth, const struct rpc_credops *ops)
 646 {
 647         INIT_HLIST_NODE(&cred->cr_hash);
 648         INIT_LIST_HEAD(&cred->cr_lru);
 649         refcount_set(&cred->cr_count, 1);
 650         cred->cr_auth = auth;
 651         cred->cr_flags = 0;
 652         cred->cr_ops = ops;
 653         cred->cr_expire = jiffies;
 654         cred->cr_cred = get_cred(acred->cred);
 655 }
 656 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 657
 658 static struct rpc_cred *
 659 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
 660 {
 661         struct rpc_auth *auth = task->tk_client->cl_auth;
 662         struct auth_cred acred = {
 663                 .cred = get_task_cred(&init_task),
 664         };
 665         struct rpc_cred *ret;
 666
 667         ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 668         put_cred(acred.cred);
 669         return ret;
 670 }
 671
 672 static struct rpc_cred *
 673 rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags)
 674 {
 675         struct rpc_auth *auth = task->tk_client->cl_auth;
 676         struct auth_cred acred = {
 677                 .principal = task->tk_client->cl_principal,
 678                 .cred = init_task.cred,
 679         };
 680
 681         if (!acred.principal)
 682                 return NULL;
 683         return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 684 }
 685
 686 static struct rpc_cred *
 687 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
 688 {
 689         struct rpc_auth *auth = task->tk_client->cl_auth;
 690
 691         return rpcauth_lookupcred(auth, lookupflags);
 692 }
 693
 694 static int
 695 rpcauth_bindcred(struct rpc_task *task, const struct cred *cred, int flags)
 696 {
 697         struct rpc_rqst *req = task->tk_rqstp;
 698         struct rpc_cred *new = NULL;
 699         int lookupflags = 0;
 700         struct rpc_auth *auth = task->tk_client->cl_auth;
 701         struct auth_cred acred = {
 702                 .cred = cred,
 703         };
 704
 705         if (flags & RPC_TASK_ASYNC)
 706                 lookupflags |= RPCAUTH_LOOKUP_NEW;
 707         if (task->tk_op_cred)
 708                 /* Task must use exactly this rpc_cred */
 709                 new = get_rpccred(task->tk_op_cred);
 710         else if (cred != NULL && cred != &machine_cred)
 711                 new = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 712         else if (cred == &machine_cred)
 713                 new = rpcauth_bind_machine_cred(task, lookupflags);
 714
 715         /* If machine cred couldn't be bound, try a root cred */
 716         if (new)
 717                 ;
 718         else if (cred == &machine_cred || (flags & RPC_TASK_ROOTCREDS))
 719                 new = rpcauth_bind_root_cred(task, lookupflags);
 720         else if (flags & RPC_TASK_NULLCREDS)
 721                 new = authnull_ops.lookup_cred(NULL, NULL, 0);
 722         else
 723                 new = rpcauth_bind_new_cred(task, lookupflags);
 724         if (IS_ERR(new))
 725                 return PTR_ERR(new);
 726         put_rpccred(req->rq_cred);
 727         req->rq_cred = new;
 728         return 0;
 729 }
 730
 731 void
 732 put_rpccred(struct rpc_cred *cred)
 733 {
 734         if (cred == NULL)
 735                 return;
 736         rcu_read_lock();
 737         if (refcount_dec_and_test(&cred->cr_count))
 738                 goto destroy;
 739         if (refcount_read(&cred->cr_count) != 1 ||
 740             !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 741                 goto out;
 742         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
 743                 cred->cr_expire = jiffies;
 744                 rpcauth_lru_add(cred);
 745                 /* Race breaker */
 746                 if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)))
 747                         rpcauth_lru_remove(cred);
 748         } else if (rpcauth_unhash_cred(cred)) {
 749                 rpcauth_lru_remove(cred);
 750                 if (refcount_dec_and_test(&cred->cr_count))
 751                         goto destroy;
 752         }
 753 out:
 754         rcu_read_unlock();
 755         return;
 756 destroy:
 757         rcu_read_unlock();
 758         cred->cr_ops->crdestroy(cred);
 759 }
 760 EXPORT_SYMBOL_GPL(put_rpccred);
 761
 762 /**
 763  * rpcauth_marshcred - Append RPC credential to end of @xdr
 764  * @task: controlling RPC task
 765  * @xdr: xdr_stream containing initial portion of RPC Call header
 766  *
 767  * On success, an appropriate verifier is added to @xdr, @xdr is
 768  * updated to point past the verifier, and zero is returned.
 769  * Otherwise, @xdr is in an undefined state and a negative errno
 770  * is returned.
 771  */
 772 int rpcauth_marshcred(struct rpc_task *task, struct xdr_stream *xdr)
 773 {
 774         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 775
 776         return ops->crmarshal(task, xdr);
 777 }
 778
 779 /**
 780  * rpcauth_wrap_req_encode - XDR encode the RPC procedure
 781  * @task: controlling RPC task
 782  * @xdr: stream where on-the-wire bytes are to be marshalled
 783  *
 784  * On success, @xdr contains the encoded and wrapped message.
 785  * Otherwise, @xdr is in an undefined state.
 786  */
 787 int rpcauth_wrap_req_encode(struct rpc_task *task, struct xdr_stream *xdr)
 788 {
 789         kxdreproc_t encode = task->tk_msg.rpc_proc->p_encode;
 790
 791         encode(task->tk_rqstp, xdr, task->tk_msg.rpc_argp);
 792         return 0;
 793 }
 794 EXPORT_SYMBOL_GPL(rpcauth_wrap_req_encode);
 795
 796 /**
 797  * rpcauth_wrap_req - XDR encode and wrap the RPC procedure
 798  * @task: controlling RPC task
 799  * @xdr: stream where on-the-wire bytes are to be marshalled
 800  *
 801  * On success, @xdr contains the encoded and wrapped message,
 802  * and zero is returned. Otherwise, @xdr is in an undefined
 803  * state and a negative errno is returned.
 804  */
 805 int rpcauth_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
 806 {
 807         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 808
 809         return ops->crwrap_req(task, xdr);
 810 }
 811
 812 /**
 813  * rpcauth_checkverf - Validate verifier in RPC Reply header
 814  * @task: controlling RPC task
 815  * @xdr: xdr_stream containing RPC Reply header
 816  *
 817  * On success, @xdr is updated to point past the verifier and
 818  * zero is returned. Otherwise, @xdr is in an undefined state
 819  * and a negative errno is returned.
 820  */
 821 int
 822 rpcauth_checkverf(struct rpc_task *task, struct xdr_stream *xdr)
 823 {
 824         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 825
 826         return ops->crvalidate(task, xdr);
 827 }
 828
 829 /**
 830  * rpcauth_unwrap_resp_decode - Invoke XDR decode function
 831  * @task: controlling RPC task
 832  * @xdr: stream where the Reply message resides
 833  *
 834  * Returns zero on success; otherwise a negative errno is returned.
 835  */
 836 int
 837 rpcauth_unwrap_resp_decode(struct rpc_task *task, struct xdr_stream *xdr)
 838 {
 839         kxdrdproc_t decode = task->tk_msg.rpc_proc->p_decode;
 840
 841         return decode(task->tk_rqstp, xdr, task->tk_msg.rpc_resp);
 842 }
 843 EXPORT_SYMBOL_GPL(rpcauth_unwrap_resp_decode);
 844
 845 /**
 846  * rpcauth_unwrap_resp - Invoke unwrap and decode function for the cred
 847  * @task: controlling RPC task
 848  * @xdr: stream where the Reply message resides
 849  *
 850  * Returns zero on success; otherwise a negative errno is returned.
 851  */
 852 int
 853 rpcauth_unwrap_resp(struct rpc_task *task, struct xdr_stream *xdr)
 854 {
 855         const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 856
 857         return ops->crunwrap_resp(task, xdr);
 858 }
 859
 860 bool
 861 rpcauth_xmit_need_reencode(struct rpc_task *task)
 862 {
 863         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 864
 865         if (!cred || !cred->cr_ops->crneed_reencode)
 866                 return false;
 867         return cred->cr_ops->crneed_reencode(task);
 868 }
 869
 870 int
 871 rpcauth_refreshcred(struct rpc_task *task)
 872 {
 873         struct rpc_cred *cred;
 874         int err;
 875
 876         cred = task->tk_rqstp->rq_cred;
 877         if (cred == NULL) {
 878                 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
 879                 if (err < 0)
 880                         goto out;
 881                 cred = task->tk_rqstp->rq_cred;
 882         }
 883
 884         err = cred->cr_ops->crrefresh(task);
 885 out:
 886         if (err < 0)
 887                 task->tk_status = err;
 888         return err;
 889 }
 890
 891 void
 892 rpcauth_invalcred(struct rpc_task *task)
 893 {
 894         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 895
 896         if (cred)
 897                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 898 }
 899
 900 int
 901 rpcauth_uptodatecred(struct rpc_task *task)
 902 {
 903         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 904
 905         return cred == NULL ||
 906                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 907 }
 908
 909 static struct shrinker rpc_cred_shrinker = {
 910         .count_objects = rpcauth_cache_shrink_count,
 911         .scan_objects = rpcauth_cache_shrink_scan,
 912         .seeks = DEFAULT_SEEKS,
 913 };
 914
 915 int __init rpcauth_init_module(void)
 916 {
 917         int err;
 918
 919         err = rpc_init_authunix();
 920         if (err < 0)
 921                 goto out1;
 922         err = register_shrinker(&rpc_cred_shrinker);
 923         if (err < 0)
 924                 goto out2;
 925         return 0;
 926 out2:
 927         rpc_destroy_authunix();
 928 out1:
 929         return err;
 930 }
 931
 932 void rpcauth_remove_module(void)
 933 {
 934         rpc_destroy_authunix();
 935         unregister_shrinker(&rpc_cred_shrinker);
 936 }