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 };
  45
  46 /*
  47  * Return the machine_cred pointer to be used whenever
  48  * the a generic machine credential is needed.
  49  */
  50 const struct cred *rpc_machine_cred(void)
  51 {
  52         return &machine_cred;
  53 }
  54 EXPORT_SYMBOL_GPL(rpc_machine_cred);
  55
  56 #define MAX_HASHTABLE_BITS (14)
  57 static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
  58 {
  59         unsigned long num;
  60         unsigned int nbits;
  61         int ret;
  62
  63         if (!val)
  64                 goto out_inval;
  65         ret = kstrtoul(val, 0, &num);
  66         if (ret)
  67                 goto out_inval;
  68         nbits = fls(num - 1);
  69         if (nbits > MAX_HASHTABLE_BITS || nbits < 2)
  70                 goto out_inval;
  71         *(unsigned int *)kp->arg = nbits;
  72         return 0;
  73 out_inval:
  74         return -EINVAL;
  75 }
  76
  77 static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
  78 {
  79         unsigned int nbits;
  80
  81         nbits = *(unsigned int *)kp->arg;
  82         return sprintf(buffer, "%u", 1U << nbits);
  83 }
  84
  85 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
  86
  87 static const struct kernel_param_ops param_ops_hashtbl_sz = {
  88         .set = param_set_hashtbl_sz,
  89         .get = param_get_hashtbl_sz,
  90 };
  91
  92 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
  93 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");
  94
  95 static unsigned long auth_max_cred_cachesize = ULONG_MAX;
  96 module_param(auth_max_cred_cachesize, ulong, 0644);
  97 MODULE_PARM_DESC(auth_max_cred_cachesize, "RPC credential maximum total cache size");
  98
  99 static u32
 100 pseudoflavor_to_flavor(u32 flavor) {
 101         if (flavor > RPC_AUTH_MAXFLAVOR)
 102                 return RPC_AUTH_GSS;
 103         return flavor;
 104 }
 105
 106 int
 107 rpcauth_register(const struct rpc_authops *ops)
 108 {
 109         const struct rpc_authops *old;
 110         rpc_authflavor_t flavor;
 111
 112         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 113                 return -EINVAL;
 114         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], NULL, ops);
 115         if (old == NULL || old == ops)
 116                 return 0;
 117         return -EPERM;
 118 }
 119 EXPORT_SYMBOL_GPL(rpcauth_register);
 120
 121 int
 122 rpcauth_unregister(const struct rpc_authops *ops)
 123 {
 124         const struct rpc_authops *old;
 125         rpc_authflavor_t flavor;
 126
 127         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
 128                 return -EINVAL;
 129
 130         old = cmpxchg((const struct rpc_authops ** __force)&auth_flavors[flavor], ops, NULL);
 131         if (old == ops || old == NULL)
 132                 return 0;
 133         return -EPERM;
 134 }
 135 EXPORT_SYMBOL_GPL(rpcauth_unregister);
 136
 137 static const struct rpc_authops *
 138 rpcauth_get_authops(rpc_authflavor_t flavor)
 139 {
 140         const struct rpc_authops *ops;
 141
 142         if (flavor >= RPC_AUTH_MAXFLAVOR)
 143                 return NULL;
 144
 145         rcu_read_lock();
 146         ops = rcu_dereference(auth_flavors[flavor]);
 147         if (ops == NULL) {
 148                 rcu_read_unlock();
 149                 request_module("rpc-auth-%u", flavor);
 150                 rcu_read_lock();
 151                 ops = rcu_dereference(auth_flavors[flavor]);
 152                 if (ops == NULL)
 153                         goto out;
 154         }
 155         if (!try_module_get(ops->owner))
 156                 ops = NULL;
 157 out:
 158         rcu_read_unlock();
 159         return ops;
 160 }
 161
 162 static void
 163 rpcauth_put_authops(const struct rpc_authops *ops)
 164 {
 165         module_put(ops->owner);
 166 }
 167
 168 /**
 169  * rpcauth_get_pseudoflavor - check if security flavor is supported
 170  * @flavor: a security flavor
 171  * @info: a GSS mech OID, quality of protection, and service value
 172  *
 173  * Verifies that an appropriate kernel module is available or already loaded.
 174  * Returns an equivalent pseudoflavor, or RPC_AUTH_MAXFLAVOR if "flavor" is
 175  * not supported locally.
 176  */
 177 rpc_authflavor_t
 178 rpcauth_get_pseudoflavor(rpc_authflavor_t flavor, struct rpcsec_gss_info *info)
 179 {
 180         const struct rpc_authops *ops = rpcauth_get_authops(flavor);
 181         rpc_authflavor_t pseudoflavor;
 182
 183         if (!ops)
 184                 return RPC_AUTH_MAXFLAVOR;
 185         pseudoflavor = flavor;
 186         if (ops->info2flavor != NULL)
 187                 pseudoflavor = ops->info2flavor(info);
 188
 189         rpcauth_put_authops(ops);
 190         return pseudoflavor;
 191 }
 192 EXPORT_SYMBOL_GPL(rpcauth_get_pseudoflavor);
 193
 194 /**
 195  * rpcauth_get_gssinfo - find GSS tuple matching a GSS pseudoflavor
 196  * @pseudoflavor: GSS pseudoflavor to match
 197  * @info: rpcsec_gss_info structure to fill in
 198  *
 199  * Returns zero and fills in "info" if pseudoflavor matches a
 200  * supported mechanism.
 201  */
 202 int
 203 rpcauth_get_gssinfo(rpc_authflavor_t pseudoflavor, struct rpcsec_gss_info *info)
 204 {
 205         rpc_authflavor_t flavor = pseudoflavor_to_flavor(pseudoflavor);
 206         const struct rpc_authops *ops;
 207         int result;
 208
 209         ops = rpcauth_get_authops(flavor);
 210         if (ops == NULL)
 211                 return -ENOENT;
 212
 213         result = -ENOENT;
 214         if (ops->flavor2info != NULL)
 215                 result = ops->flavor2info(pseudoflavor, info);
 216
 217         rpcauth_put_authops(ops);
 218         return result;
 219 }
 220 EXPORT_SYMBOL_GPL(rpcauth_get_gssinfo);
 221
 222 /**
 223  * rpcauth_list_flavors - discover registered flavors and pseudoflavors
 224  * @array: array to fill in
 225  * @size: size of "array"
 226  *
 227  * Returns the number of array items filled in, or a negative errno.
 228  *
 229  * The returned array is not sorted by any policy.  Callers should not
 230  * rely on the order of the items in the returned array.
 231  */
 232 int
 233 rpcauth_list_flavors(rpc_authflavor_t *array, int size)
 234 {
 235         const struct rpc_authops *ops;
 236         rpc_authflavor_t flavor, pseudos[4];
 237         int i, len, result = 0;
 238
 239         rcu_read_lock();
 240         for (flavor = 0; flavor < RPC_AUTH_MAXFLAVOR; flavor++) {
 241                 ops = rcu_dereference(auth_flavors[flavor]);
 242                 if (result >= size) {
 243                         result = -ENOMEM;
 244                         break;
 245                 }
 246
 247                 if (ops == NULL)
 248                         continue;
 249                 if (ops->list_pseudoflavors == NULL) {
 250                         array[result++] = ops->au_flavor;
 251                         continue;
 252                 }
 253                 len = ops->list_pseudoflavors(pseudos, ARRAY_SIZE(pseudos));
 254                 if (len < 0) {
 255                         result = len;
 256                         break;
 257                 }
 258                 for (i = 0; i < len; i++) {
 259                         if (result >= size) {
 260                                 result = -ENOMEM;
 261                                 break;
 262                         }
 263                         array[result++] = pseudos[i];
 264                 }
 265         }
 266         rcu_read_unlock();
 267
 268         dprintk("RPC:       %s returns %d\n", __func__, result);
 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         dprintk("RPC:       looking up %s cred\n",
 637                 auth->au_ops->au_name);
 638
 639         memset(&acred, 0, sizeof(acred));
 640         acred.cred = cred;
 641         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 642         return ret;
 643 }
 644 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
 645
 646 void
 647 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 648                   struct rpc_auth *auth, const struct rpc_credops *ops)
 649 {
 650         INIT_HLIST_NODE(&cred->cr_hash);
 651         INIT_LIST_HEAD(&cred->cr_lru);
 652         refcount_set(&cred->cr_count, 1);
 653         cred->cr_auth = auth;
 654         cred->cr_flags = 0;
 655         cred->cr_ops = ops;
 656         cred->cr_expire = jiffies;
 657         cred->cr_cred = get_cred(acred->cred);
 658 }
 659 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 660
 661 static struct rpc_cred *
 662 rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
 663 {
 664         struct rpc_auth *auth = task->tk_client->cl_auth;
 665         struct auth_cred acred = {
 666                 .cred = get_task_cred(&init_task),
 667         };
 668         struct rpc_cred *ret;
 669
 670         dprintk("RPC: %5u looking up %s cred\n",
 671                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
 672         ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 673         put_cred(acred.cred);
 674         return ret;
 675 }
 676
 677 static struct rpc_cred *
 678 rpcauth_bind_machine_cred(struct rpc_task *task, int lookupflags)
 679 {
 680         struct rpc_auth *auth = task->tk_client->cl_auth;
 681         struct auth_cred acred = {
 682                 .principal = task->tk_client->cl_principal,
 683                 .cred = init_task.cred,
 684         };
 685
 686         if (!acred.principal)
 687                 return NULL;
 688         dprintk("RPC: %5u looking up %s machine cred\n",
 689                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
 690         return auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 691 }
 692
 693 static struct rpc_cred *
 694 rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
 695 {
 696         struct rpc_auth *auth = task->tk_client->cl_auth;
 697
 698         dprintk("RPC: %5u looking up %s cred\n",
 699                 task->tk_pid, auth->au_ops->au_name);
 700         return rpcauth_lookupcred(auth, lookupflags);
 701 }
 702
 703 static int
 704 rpcauth_bindcred(struct rpc_task *task, const struct cred *cred, int flags)
 705 {
 706         struct rpc_rqst *req = task->tk_rqstp;
 707         struct rpc_cred *new = NULL;
 708         int lookupflags = 0;
 709         struct rpc_auth *auth = task->tk_client->cl_auth;
 710         struct auth_cred acred = {
 711                 .cred = cred,
 712         };
 713
 714         if (flags & RPC_TASK_ASYNC)
 715                 lookupflags |= RPCAUTH_LOOKUP_NEW;
 716         if (task->tk_op_cred)
 717                 /* Task must use exactly this rpc_cred */
 718                 new = get_rpccred(task->tk_op_cred);
 719         else if (cred != NULL && cred != &machine_cred)
 720                 new = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 721         else if (cred == &machine_cred)
 722                 new = rpcauth_bind_machine_cred(task, lookupflags);
 723
 724         /* If machine cred couldn't be bound, try a root cred */
 725         if (new)
 726                 ;
 727         else if (cred == &machine_cred || (flags & RPC_TASK_ROOTCREDS))
 728                 new = rpcauth_bind_root_cred(task, lookupflags);
 729         else if (flags & RPC_TASK_NULLCREDS)
 730                 new = authnull_ops.lookup_cred(NULL, NULL, 0);
 731         else
 732                 new = rpcauth_bind_new_cred(task, lookupflags);
 733         if (IS_ERR(new))
 734                 return PTR_ERR(new);
 735         put_rpccred(req->rq_cred);
 736         req->rq_cred = new;
 737         return 0;
 738 }
 739
 740 void
 741 put_rpccred(struct rpc_cred *cred)
 742 {
 743         if (cred == NULL)
 744                 return;
 745         rcu_read_lock();
 746         if (refcount_dec_and_test(&cred->cr_count))
 747                 goto destroy;
 748         if (refcount_read(&cred->cr_count) != 1 ||
 749             !test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags))
 750                 goto out;
 751         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
 752                 cred->cr_expire = jiffies;
 753                 rpcauth_lru_add(cred);
 754                 /* Race breaker */
 755                 if (unlikely(!test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags)))
 756                         rpcauth_lru_remove(cred);
 757         } else if (rpcauth_unhash_cred(cred)) {
 758                 rpcauth_lru_remove(cred);
 759                 if (refcount_dec_and_test(&cred->cr_count))
 760                         goto destroy;
 761         }
 762 out:
 763         rcu_read_unlock();
 764         return;
 765 destroy:
 766         rcu_read_unlock();
 767         cred->cr_ops->crdestroy(cred);
 768 }
 769 EXPORT_SYMBOL_GPL(put_rpccred);
 770
 771 __be32 *
 772 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
 773 {
 774         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 775
 776         dprintk("RPC: %5u marshaling %s cred %p\n",
 777                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 778
 779         return cred->cr_ops->crmarshal(task, p);
 780 }
 781
 782 __be32 *
 783 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
 784 {
 785         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 786
 787         dprintk("RPC: %5u validating %s cred %p\n",
 788                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 789
 790         return cred->cr_ops->crvalidate(task, p);
 791 }
 792
 793 static void rpcauth_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
 794                                    __be32 *data, void *obj)
 795 {
 796         struct xdr_stream xdr;
 797
 798         xdr_init_encode(&xdr, &rqstp->rq_snd_buf, data);
 799         encode(rqstp, &xdr, obj);
 800 }
 801
 802 int
 803 rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp,
 804                 __be32 *data, void *obj)
 805 {
 806         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 807
 808         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
 809                         task->tk_pid, cred->cr_ops->cr_name, cred);
 810         if (cred->cr_ops->crwrap_req)
 811                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
 812         /* By default, we encode the arguments normally. */
 813         rpcauth_wrap_req_encode(encode, rqstp, data, obj);
 814         return 0;
 815 }
 816
 817 static int
 818 rpcauth_unwrap_req_decode(kxdrdproc_t decode, struct rpc_rqst *rqstp,
 819                           __be32 *data, void *obj)
 820 {
 821         struct xdr_stream xdr;
 822
 823         xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, data);
 824         return decode(rqstp, &xdr, obj);
 825 }
 826
 827 int
 828 rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp,
 829                 __be32 *data, void *obj)
 830 {
 831         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 832
 833         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
 834                         task->tk_pid, cred->cr_ops->cr_name, cred);
 835         if (cred->cr_ops->crunwrap_resp)
 836                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
 837                                                    data, obj);
 838         /* By default, we decode the arguments normally. */
 839         return rpcauth_unwrap_req_decode(decode, rqstp, data, obj);
 840 }
 841
 842 bool
 843 rpcauth_xmit_need_reencode(struct rpc_task *task)
 844 {
 845         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 846
 847         if (!cred || !cred->cr_ops->crneed_reencode)
 848                 return false;
 849         return cred->cr_ops->crneed_reencode(task);
 850 }
 851
 852 int
 853 rpcauth_refreshcred(struct rpc_task *task)
 854 {
 855         struct rpc_cred *cred;
 856         int err;
 857
 858         cred = task->tk_rqstp->rq_cred;
 859         if (cred == NULL) {
 860                 err = rpcauth_bindcred(task, task->tk_msg.rpc_cred, task->tk_flags);
 861                 if (err < 0)
 862                         goto out;
 863                 cred = task->tk_rqstp->rq_cred;
 864         }
 865         dprintk("RPC: %5u refreshing %s cred %p\n",
 866                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 867
 868         err = cred->cr_ops->crrefresh(task);
 869 out:
 870         if (err < 0)
 871                 task->tk_status = err;
 872         return err;
 873 }
 874
 875 void
 876 rpcauth_invalcred(struct rpc_task *task)
 877 {
 878         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 879
 880         dprintk("RPC: %5u invalidating %s cred %p\n",
 881                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 882         if (cred)
 883                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 884 }
 885
 886 int
 887 rpcauth_uptodatecred(struct rpc_task *task)
 888 {
 889         struct rpc_cred *cred = task->tk_rqstp->rq_cred;
 890
 891         return cred == NULL ||
 892                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 893 }
 894
 895 static struct shrinker rpc_cred_shrinker = {
 896         .count_objects = rpcauth_cache_shrink_count,
 897         .scan_objects = rpcauth_cache_shrink_scan,
 898         .seeks = DEFAULT_SEEKS,
 899 };
 900
 901 int __init rpcauth_init_module(void)
 902 {
 903         int err;
 904
 905         err = rpc_init_authunix();
 906         if (err < 0)
 907                 goto out1;
 908         err = register_shrinker(&rpc_cred_shrinker);
 909         if (err < 0)
 910                 goto out2;
 911         return 0;
 912 out2:
 913         rpc_destroy_authunix();
 914 out1:
 915         return err;
 916 }
 917
 918 void rpcauth_remove_module(void)
 919 {
 920         rpc_destroy_authunix();
 921         unregister_shrinker(&rpc_cred_shrinker);
 922 }