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