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