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   1 /*
   2  * linux/net/sunrpc/auth.c
   3  *
   4  * Generic RPC client authentication API.
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/sched.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/errno.h>
  14 #include <linux/hash.h>
  15 #include <linux/sunrpc/clnt.h>
  16 #include <linux/spinlock.h>
  17
  18 #ifdef RPC_DEBUG
  19 # define RPCDBG_FACILITY        RPCDBG_AUTH
  20 #endif
  21
  22 static DEFINE_SPINLOCK(rpc_authflavor_lock);
  23 static const struct rpc_authops *auth_flavors[RPC_AUTH_MAXFLAVOR] = {
  24         &authnull_ops,          /* AUTH_NULL */
  25         &authunix_ops,          /* AUTH_UNIX */
  26         NULL,                   /* others can be loadable modules */
  27 };
  28
  29 static LIST_HEAD(cred_unused);
  30 static unsigned long number_cred_unused;
  31
  32 static u32
  33 pseudoflavor_to_flavor(u32 flavor) {
  34         if (flavor >= RPC_AUTH_MAXFLAVOR)
  35                 return RPC_AUTH_GSS;
  36         return flavor;
  37 }
  38
  39 int
  40 rpcauth_register(const struct rpc_authops *ops)
  41 {
  42         rpc_authflavor_t flavor;
  43         int ret = -EPERM;
  44
  45         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
  46                 return -EINVAL;
  47         spin_lock(&rpc_authflavor_lock);
  48         if (auth_flavors[flavor] == NULL) {
  49                 auth_flavors[flavor] = ops;
  50                 ret = 0;
  51         }
  52         spin_unlock(&rpc_authflavor_lock);
  53         return ret;
  54 }
  55 EXPORT_SYMBOL_GPL(rpcauth_register);
  56
  57 int
  58 rpcauth_unregister(const struct rpc_authops *ops)
  59 {
  60         rpc_authflavor_t flavor;
  61         int ret = -EPERM;
  62
  63         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
  64                 return -EINVAL;
  65         spin_lock(&rpc_authflavor_lock);
  66         if (auth_flavors[flavor] == ops) {
  67                 auth_flavors[flavor] = NULL;
  68                 ret = 0;
  69         }
  70         spin_unlock(&rpc_authflavor_lock);
  71         return ret;
  72 }
  73 EXPORT_SYMBOL_GPL(rpcauth_unregister);
  74
  75 struct rpc_auth *
  76 rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
  77 {
  78         struct rpc_auth         *auth;
  79         const struct rpc_authops *ops;
  80         u32                     flavor = pseudoflavor_to_flavor(pseudoflavor);
  81
  82         auth = ERR_PTR(-EINVAL);
  83         if (flavor >= RPC_AUTH_MAXFLAVOR)
  84                 goto out;
  85
  86 #ifdef CONFIG_KMOD
  87         if ((ops = auth_flavors[flavor]) == NULL)
  88                 request_module("rpc-auth-%u", flavor);
  89 #endif
  90         spin_lock(&rpc_authflavor_lock);
  91         ops = auth_flavors[flavor];
  92         if (ops == NULL || !try_module_get(ops->owner)) {
  93                 spin_unlock(&rpc_authflavor_lock);
  94                 goto out;
  95         }
  96         spin_unlock(&rpc_authflavor_lock);
  97         auth = ops->create(clnt, pseudoflavor);
  98         module_put(ops->owner);
  99         if (IS_ERR(auth))
 100                 return auth;
 101         if (clnt->cl_auth)
 102                 rpcauth_release(clnt->cl_auth);
 103         clnt->cl_auth = auth;
 104
 105 out:
 106         return auth;
 107 }
 108 EXPORT_SYMBOL_GPL(rpcauth_create);
 109
 110 void
 111 rpcauth_release(struct rpc_auth *auth)
 112 {
 113         if (!atomic_dec_and_test(&auth->au_count))
 114                 return;
 115         auth->au_ops->destroy(auth);
 116 }
 117
 118 static DEFINE_SPINLOCK(rpc_credcache_lock);
 119
 120 static void
 121 rpcauth_unhash_cred_locked(struct rpc_cred *cred)
 122 {
 123         hlist_del_rcu(&cred->cr_hash);
 124         smp_mb__before_clear_bit();
 125         clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 126 }
 127
 128 static void
 129 rpcauth_unhash_cred(struct rpc_cred *cred)
 130 {
 131         spinlock_t *cache_lock;
 132
 133         cache_lock = &cred->cr_auth->au_credcache->lock;
 134         spin_lock(cache_lock);
 135         if (atomic_read(&cred->cr_count) == 0)
 136                 rpcauth_unhash_cred_locked(cred);
 137         spin_unlock(cache_lock);
 138 }
 139
 140 /*
 141  * Initialize RPC credential cache
 142  */
 143 int
 144 rpcauth_init_credcache(struct rpc_auth *auth)
 145 {
 146         struct rpc_cred_cache *new;
 147         int i;
 148
 149         new = kmalloc(sizeof(*new), GFP_KERNEL);
 150         if (!new)
 151                 return -ENOMEM;
 152         for (i = 0; i < RPC_CREDCACHE_NR; i++)
 153                 INIT_HLIST_HEAD(&new->hashtable[i]);
 154         spin_lock_init(&new->lock);
 155         auth->au_credcache = new;
 156         return 0;
 157 }
 158 EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
 159
 160 /*
 161  * Destroy a list of credentials
 162  */
 163 static inline
 164 void rpcauth_destroy_credlist(struct list_head *head)
 165 {
 166         struct rpc_cred *cred;
 167
 168         while (!list_empty(head)) {
 169                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
 170                 list_del_init(&cred->cr_lru);
 171                 put_rpccred(cred);
 172         }
 173 }
 174
 175 /*
 176  * Clear the RPC credential cache, and delete those credentials
 177  * that are not referenced.
 178  */
 179 void
 180 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
 181 {
 182         LIST_HEAD(free);
 183         struct hlist_head *head;
 184         struct rpc_cred *cred;
 185         int             i;
 186
 187         spin_lock(&rpc_credcache_lock);
 188         spin_lock(&cache->lock);
 189         for (i = 0; i < RPC_CREDCACHE_NR; i++) {
 190                 head = &cache->hashtable[i];
 191                 while (!hlist_empty(head)) {
 192                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
 193                         get_rpccred(cred);
 194                         if (!list_empty(&cred->cr_lru)) {
 195                                 list_del(&cred->cr_lru);
 196                                 number_cred_unused--;
 197                         }
 198                         list_add_tail(&cred->cr_lru, &free);
 199                         rpcauth_unhash_cred_locked(cred);
 200                 }
 201         }
 202         spin_unlock(&cache->lock);
 203         spin_unlock(&rpc_credcache_lock);
 204         rpcauth_destroy_credlist(&free);
 205 }
 206
 207 /*
 208  * Destroy the RPC credential cache
 209  */
 210 void
 211 rpcauth_destroy_credcache(struct rpc_auth *auth)
 212 {
 213         struct rpc_cred_cache *cache = auth->au_credcache;
 214
 215         if (cache) {
 216                 auth->au_credcache = NULL;
 217                 rpcauth_clear_credcache(cache);
 218                 kfree(cache);
 219         }
 220 }
 221 EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
 222
 223 /*
 224  * Remove stale credentials. Avoid sleeping inside the loop.
 225  */
 226 static int
 227 rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
 228 {
 229         spinlock_t *cache_lock;
 230         struct rpc_cred *cred;
 231
 232         while (!list_empty(&cred_unused)) {
 233                 cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru);
 234                 list_del_init(&cred->cr_lru);
 235                 number_cred_unused--;
 236                 if (atomic_read(&cred->cr_count) != 0)
 237                         continue;
 238                 cache_lock = &cred->cr_auth->au_credcache->lock;
 239                 spin_lock(cache_lock);
 240                 if (atomic_read(&cred->cr_count) == 0) {
 241                         get_rpccred(cred);
 242                         list_add_tail(&cred->cr_lru, free);
 243                         rpcauth_unhash_cred_locked(cred);
 244                         nr_to_scan--;
 245                 }
 246                 spin_unlock(cache_lock);
 247                 if (nr_to_scan == 0)
 248                         break;
 249         }
 250         return nr_to_scan;
 251 }
 252
 253 /*
 254  * Run memory cache shrinker.
 255  */
 256 static int
 257 rpcauth_cache_shrinker(int nr_to_scan, gfp_t gfp_mask)
 258 {
 259         LIST_HEAD(free);
 260         int res;
 261
 262         if (list_empty(&cred_unused))
 263                 return 0;
 264         spin_lock(&rpc_credcache_lock);
 265         nr_to_scan = rpcauth_prune_expired(&free, nr_to_scan);
 266         res = (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
 267         spin_unlock(&rpc_credcache_lock);
 268         rpcauth_destroy_credlist(&free);
 269         return res;
 270 }
 271
 272 /*
 273  * Look up a process' credentials in the authentication cache
 274  */
 275 struct rpc_cred *
 276 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 277                 int flags)
 278 {
 279         LIST_HEAD(free);
 280         struct rpc_cred_cache *cache = auth->au_credcache;
 281         struct hlist_node *pos;
 282         struct rpc_cred *cred = NULL,
 283                         *entry, *new;
 284         unsigned int nr;
 285
 286         nr = hash_long(acred->uid, RPC_CREDCACHE_HASHBITS);
 287
 288         rcu_read_lock();
 289         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
 290                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 291                         continue;
 292                 spin_lock(&cache->lock);
 293                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
 294                         spin_unlock(&cache->lock);
 295                         continue;
 296                 }
 297                 cred = get_rpccred(entry);
 298                 spin_unlock(&cache->lock);
 299                 break;
 300         }
 301         rcu_read_unlock();
 302
 303         if (cred != NULL)
 304                 goto found;
 305
 306         new = auth->au_ops->crcreate(auth, acred, flags);
 307         if (IS_ERR(new)) {
 308                 cred = new;
 309                 goto out;
 310         }
 311
 312         spin_lock(&cache->lock);
 313         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
 314                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 315                         continue;
 316                 cred = get_rpccred(entry);
 317                 break;
 318         }
 319         if (cred == NULL) {
 320                 cred = new;
 321                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 322                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
 323         } else
 324                 list_add_tail(&new->cr_lru, &free);
 325         spin_unlock(&cache->lock);
 326 found:
 327         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
 328                         && cred->cr_ops->cr_init != NULL
 329                         && !(flags & RPCAUTH_LOOKUP_NEW)) {
 330                 int res = cred->cr_ops->cr_init(auth, cred);
 331                 if (res < 0) {
 332                         put_rpccred(cred);
 333                         cred = ERR_PTR(res);
 334                 }
 335         }
 336         rpcauth_destroy_credlist(&free);
 337 out:
 338         return cred;
 339 }
 340 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
 341
 342 struct rpc_cred *
 343 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 344 {
 345         struct auth_cred acred = {
 346                 .uid = current->fsuid,
 347                 .gid = current->fsgid,
 348                 .group_info = current->group_info,
 349         };
 350         struct rpc_cred *ret;
 351
 352         dprintk("RPC:       looking up %s cred\n",
 353                 auth->au_ops->au_name);
 354         get_group_info(acred.group_info);
 355         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 356         put_group_info(acred.group_info);
 357         return ret;
 358 }
 359 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
 360
 361 void
 362 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 363                   struct rpc_auth *auth, const struct rpc_credops *ops)
 364 {
 365         INIT_HLIST_NODE(&cred->cr_hash);
 366         INIT_LIST_HEAD(&cred->cr_lru);
 367         atomic_set(&cred->cr_count, 1);
 368         cred->cr_auth = auth;
 369         cred->cr_ops = ops;
 370         cred->cr_expire = jiffies;
 371 #ifdef RPC_DEBUG
 372         cred->cr_magic = RPCAUTH_CRED_MAGIC;
 373 #endif
 374         cred->cr_uid = acred->uid;
 375 }
 376 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 377
 378 void
 379 rpcauth_bind_root_cred(struct rpc_task *task)
 380 {
 381         struct rpc_auth *auth = task->tk_client->cl_auth;
 382         struct auth_cred acred = {
 383                 .uid = 0,
 384                 .gid = 0,
 385         };
 386         struct rpc_cred *ret;
 387
 388         dprintk("RPC: %5u looking up %s cred\n",
 389                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
 390         ret = auth->au_ops->lookup_cred(auth, &acred, 0);
 391         if (!IS_ERR(ret))
 392                 task->tk_msg.rpc_cred = ret;
 393         else
 394                 task->tk_status = PTR_ERR(ret);
 395 }
 396
 397 void
 398 rpcauth_bindcred(struct rpc_task *task)
 399 {
 400         struct rpc_auth *auth = task->tk_client->cl_auth;
 401         struct rpc_cred *ret;
 402
 403         dprintk("RPC: %5u looking up %s cred\n",
 404                 task->tk_pid, auth->au_ops->au_name);
 405         ret = rpcauth_lookupcred(auth, 0);
 406         if (!IS_ERR(ret))
 407                 task->tk_msg.rpc_cred = ret;
 408         else
 409                 task->tk_status = PTR_ERR(ret);
 410 }
 411
 412 void
 413 rpcauth_holdcred(struct rpc_task *task)
 414 {
 415         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 416         if (cred != NULL) {
 417                 get_rpccred(cred);
 418                 dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
 419                                 cred->cr_auth->au_ops->au_name, cred);
 420         }
 421 }
 422
 423 void
 424 put_rpccred(struct rpc_cred *cred)
 425 {
 426         /* Fast path for unhashed credentials */
 427         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
 428                 goto need_lock;
 429
 430         if (!atomic_dec_and_test(&cred->cr_count))
 431                 return;
 432         goto out_destroy;
 433 need_lock:
 434         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
 435                 return;
 436         if (!list_empty(&cred->cr_lru)) {
 437                 number_cred_unused--;
 438                 list_del_init(&cred->cr_lru);
 439         }
 440         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
 441                 rpcauth_unhash_cred(cred);
 442         else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
 443                 cred->cr_expire = jiffies;
 444                 list_add_tail(&cred->cr_lru, &cred_unused);
 445                 number_cred_unused++;
 446                 spin_unlock(&rpc_credcache_lock);
 447                 return;
 448         }
 449         spin_unlock(&rpc_credcache_lock);
 450 out_destroy:
 451         cred->cr_ops->crdestroy(cred);
 452 }
 453 EXPORT_SYMBOL_GPL(put_rpccred);
 454
 455 void
 456 rpcauth_unbindcred(struct rpc_task *task)
 457 {
 458         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 459
 460         dprintk("RPC: %5u releasing %s cred %p\n",
 461                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 462
 463         put_rpccred(cred);
 464         task->tk_msg.rpc_cred = NULL;
 465 }
 466
 467 __be32 *
 468 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
 469 {
 470         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 471
 472         dprintk("RPC: %5u marshaling %s cred %p\n",
 473                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 474
 475         return cred->cr_ops->crmarshal(task, p);
 476 }
 477
 478 __be32 *
 479 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
 480 {
 481         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 482
 483         dprintk("RPC: %5u validating %s cred %p\n",
 484                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 485
 486         return cred->cr_ops->crvalidate(task, p);
 487 }
 488
 489 int
 490 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
 491                 __be32 *data, void *obj)
 492 {
 493         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 494
 495         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
 496                         task->tk_pid, cred->cr_ops->cr_name, cred);
 497         if (cred->cr_ops->crwrap_req)
 498                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
 499         /* By default, we encode the arguments normally. */
 500         return rpc_call_xdrproc(encode, rqstp, data, obj);
 501 }
 502
 503 int
 504 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
 505                 __be32 *data, void *obj)
 506 {
 507         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 508
 509         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
 510                         task->tk_pid, cred->cr_ops->cr_name, cred);
 511         if (cred->cr_ops->crunwrap_resp)
 512                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
 513                                                    data, obj);
 514         /* By default, we decode the arguments normally. */
 515         return rpc_call_xdrproc(decode, rqstp, data, obj);
 516 }
 517
 518 int
 519 rpcauth_refreshcred(struct rpc_task *task)
 520 {
 521         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 522         int err;
 523
 524         dprintk("RPC: %5u refreshing %s cred %p\n",
 525                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 526
 527         err = cred->cr_ops->crrefresh(task);
 528         if (err < 0)
 529                 task->tk_status = err;
 530         return err;
 531 }
 532
 533 void
 534 rpcauth_invalcred(struct rpc_task *task)
 535 {
 536         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 537
 538         dprintk("RPC: %5u invalidating %s cred %p\n",
 539                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 540         if (cred)
 541                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 542 }
 543
 544 int
 545 rpcauth_uptodatecred(struct rpc_task *task)
 546 {
 547         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 548
 549         return cred == NULL ||
 550                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 551 }
 552
 553 static struct shrinker rpc_cred_shrinker = {
 554         .shrink = rpcauth_cache_shrinker,
 555         .seeks = DEFAULT_SEEKS,
 556 };
 557
 558 void __init rpcauth_init_module(void)
 559 {
 560         rpc_init_authunix();
 561         register_shrinker(&rpc_cred_shrinker);
 562 }
 563
 564 void __exit rpcauth_remove_module(void)
 565 {
 566         unregister_shrinker(&rpc_cred_shrinker);
 567 }