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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         if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
 289                 nr = acred->uid & RPC_CREDCACHE_MASK;
 290
 291         rcu_read_lock();
 292         hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
 293                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 294                         continue;
 295                 spin_lock(&cache->lock);
 296                 if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
 297                         spin_unlock(&cache->lock);
 298                         continue;
 299                 }
 300                 cred = get_rpccred(entry);
 301                 spin_unlock(&cache->lock);
 302                 break;
 303         }
 304         rcu_read_unlock();
 305
 306         if (cred != NULL)
 307                 goto found;
 308
 309         new = auth->au_ops->crcreate(auth, acred, flags);
 310         if (IS_ERR(new)) {
 311                 cred = new;
 312                 goto out;
 313         }
 314
 315         spin_lock(&cache->lock);
 316         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
 317                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 318                         continue;
 319                 cred = get_rpccred(entry);
 320                 break;
 321         }
 322         if (cred == NULL) {
 323                 cred = new;
 324                 set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 325                 hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
 326         } else
 327                 list_add_tail(&new->cr_lru, &free);
 328         spin_unlock(&cache->lock);
 329 found:
 330         if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
 331                         && cred->cr_ops->cr_init != NULL
 332                         && !(flags & RPCAUTH_LOOKUP_NEW)) {
 333                 int res = cred->cr_ops->cr_init(auth, cred);
 334                 if (res < 0) {
 335                         put_rpccred(cred);
 336                         cred = ERR_PTR(res);
 337                 }
 338         }
 339         rpcauth_destroy_credlist(&free);
 340 out:
 341         return cred;
 342 }
 343 EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
 344
 345 struct rpc_cred *
 346 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 347 {
 348         struct auth_cred acred = {
 349                 .uid = current->fsuid,
 350                 .gid = current->fsgid,
 351                 .group_info = current->group_info,
 352         };
 353         struct rpc_cred *ret;
 354
 355         dprintk("RPC:       looking up %s cred\n",
 356                 auth->au_ops->au_name);
 357         get_group_info(acred.group_info);
 358         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 359         put_group_info(acred.group_info);
 360         return ret;
 361 }
 362 EXPORT_SYMBOL_GPL(rpcauth_lookupcred);
 363
 364 void
 365 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 366                   struct rpc_auth *auth, const struct rpc_credops *ops)
 367 {
 368         INIT_HLIST_NODE(&cred->cr_hash);
 369         INIT_LIST_HEAD(&cred->cr_lru);
 370         atomic_set(&cred->cr_count, 1);
 371         cred->cr_auth = auth;
 372         cred->cr_ops = ops;
 373         cred->cr_expire = jiffies;
 374 #ifdef RPC_DEBUG
 375         cred->cr_magic = RPCAUTH_CRED_MAGIC;
 376 #endif
 377         cred->cr_uid = acred->uid;
 378 }
 379 EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 380
 381 struct rpc_cred *
 382 rpcauth_bindcred(struct rpc_task *task)
 383 {
 384         struct rpc_auth *auth = task->tk_client->cl_auth;
 385         struct auth_cred acred = {
 386                 .uid = current->fsuid,
 387                 .gid = current->fsgid,
 388                 .group_info = current->group_info,
 389         };
 390         struct rpc_cred *ret;
 391         int flags = 0;
 392
 393         dprintk("RPC: %5u looking up %s cred\n",
 394                 task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
 395         get_group_info(acred.group_info);
 396         if (task->tk_flags & RPC_TASK_ROOTCREDS)
 397                 flags |= RPCAUTH_LOOKUP_ROOTCREDS;
 398         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 399         if (!IS_ERR(ret))
 400                 task->tk_msg.rpc_cred = ret;
 401         else
 402                 task->tk_status = PTR_ERR(ret);
 403         put_group_info(acred.group_info);
 404         return ret;
 405 }
 406
 407 void
 408 rpcauth_holdcred(struct rpc_task *task)
 409 {
 410         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 411         if (cred != NULL) {
 412                 get_rpccred(cred);
 413                 dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
 414                                 cred->cr_auth->au_ops->au_name, cred);
 415         }
 416 }
 417
 418 void
 419 put_rpccred(struct rpc_cred *cred)
 420 {
 421         /* Fast path for unhashed credentials */
 422         if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
 423                 goto need_lock;
 424
 425         if (!atomic_dec_and_test(&cred->cr_count))
 426                 return;
 427         goto out_destroy;
 428 need_lock:
 429         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
 430                 return;
 431         if (!list_empty(&cred->cr_lru)) {
 432                 number_cred_unused--;
 433                 list_del_init(&cred->cr_lru);
 434         }
 435         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
 436                 rpcauth_unhash_cred(cred);
 437         else if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
 438                 cred->cr_expire = jiffies;
 439                 list_add_tail(&cred->cr_lru, &cred_unused);
 440                 number_cred_unused++;
 441                 spin_unlock(&rpc_credcache_lock);
 442                 return;
 443         }
 444         spin_unlock(&rpc_credcache_lock);
 445 out_destroy:
 446         cred->cr_ops->crdestroy(cred);
 447 }
 448 EXPORT_SYMBOL_GPL(put_rpccred);
 449
 450 void
 451 rpcauth_unbindcred(struct rpc_task *task)
 452 {
 453         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 454
 455         dprintk("RPC: %5u releasing %s cred %p\n",
 456                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 457
 458         put_rpccred(cred);
 459         task->tk_msg.rpc_cred = NULL;
 460 }
 461
 462 __be32 *
 463 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
 464 {
 465         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 466
 467         dprintk("RPC: %5u marshaling %s cred %p\n",
 468                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 469
 470         return cred->cr_ops->crmarshal(task, p);
 471 }
 472
 473 __be32 *
 474 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
 475 {
 476         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 477
 478         dprintk("RPC: %5u validating %s cred %p\n",
 479                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 480
 481         return cred->cr_ops->crvalidate(task, p);
 482 }
 483
 484 int
 485 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
 486                 __be32 *data, void *obj)
 487 {
 488         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 489
 490         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
 491                         task->tk_pid, cred->cr_ops->cr_name, cred);
 492         if (cred->cr_ops->crwrap_req)
 493                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
 494         /* By default, we encode the arguments normally. */
 495         return rpc_call_xdrproc(encode, rqstp, data, obj);
 496 }
 497
 498 int
 499 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
 500                 __be32 *data, void *obj)
 501 {
 502         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 503
 504         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
 505                         task->tk_pid, cred->cr_ops->cr_name, cred);
 506         if (cred->cr_ops->crunwrap_resp)
 507                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
 508                                                    data, obj);
 509         /* By default, we decode the arguments normally. */
 510         return rpc_call_xdrproc(decode, rqstp, data, obj);
 511 }
 512
 513 int
 514 rpcauth_refreshcred(struct rpc_task *task)
 515 {
 516         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 517         int err;
 518
 519         dprintk("RPC: %5u refreshing %s cred %p\n",
 520                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 521
 522         err = cred->cr_ops->crrefresh(task);
 523         if (err < 0)
 524                 task->tk_status = err;
 525         return err;
 526 }
 527
 528 void
 529 rpcauth_invalcred(struct rpc_task *task)
 530 {
 531         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 532
 533         dprintk("RPC: %5u invalidating %s cred %p\n",
 534                 task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 535         if (cred)
 536                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 537 }
 538
 539 int
 540 rpcauth_uptodatecred(struct rpc_task *task)
 541 {
 542         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 543
 544         return cred == NULL ||
 545                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 546 }
 547
 548 static struct shrinker rpc_cred_shrinker = {
 549         .shrink = rpcauth_cache_shrinker,
 550         .seeks = DEFAULT_SEEKS,
 551 };
 552
 553 void __init rpcauth_init_module(void)
 554 {
 555         rpc_init_authunix();
 556         register_shrinker(&rpc_cred_shrinker);
 557 }
 558
 559 void __exit rpcauth_remove_module(void)
 560 {
 561         unregister_shrinker(&rpc_cred_shrinker);
 562 }