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 /*
 116  * Initialize RPC credential cache
 117  */
 118 int
 119 rpcauth_init_credcache(struct rpc_auth *auth, unsigned long expire)
 120 {
 121         struct rpc_cred_cache *new;
 122         int i;
 123
 124         new = kmalloc(sizeof(*new), GFP_KERNEL);
 125         if (!new)
 126                 return -ENOMEM;
 127         for (i = 0; i < RPC_CREDCACHE_NR; i++)
 128                 INIT_HLIST_HEAD(&new->hashtable[i]);
 129         new->expire = expire;
 130         new->nextgc = jiffies + (expire >> 1);
 131         auth->au_credcache = new;
 132         return 0;
 133 }
 134
 135 /*
 136  * Destroy a list of credentials
 137  */
 138 static inline
 139 void rpcauth_destroy_credlist(struct list_head *head)
 140 {
 141         struct rpc_cred *cred;
 142
 143         while (!list_empty(head)) {
 144                 cred = list_entry(head->next, struct rpc_cred, cr_lru);
 145                 list_del_init(&cred->cr_lru);
 146                 put_rpccred(cred);
 147         }
 148 }
 149
 150 /*
 151  * Clear the RPC credential cache, and delete those credentials
 152  * that are not referenced.
 153  */
 154 void
 155 rpcauth_clear_credcache(struct rpc_cred_cache *cache)
 156 {
 157         LIST_HEAD(free);
 158         struct hlist_head *head;
 159         struct rpc_cred *cred;
 160         int             i;
 161
 162         spin_lock(&rpc_credcache_lock);
 163         for (i = 0; i < RPC_CREDCACHE_NR; i++) {
 164                 head = &cache->hashtable[i];
 165                 while (!hlist_empty(head)) {
 166                         cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
 167                         get_rpccred(cred);
 168                         list_move_tail(&cred->cr_lru, &free);
 169                         smp_wmb();
 170                         hlist_del_init(&cred->cr_hash);
 171                 }
 172         }
 173         spin_unlock(&rpc_credcache_lock);
 174         rpcauth_destroy_credlist(&free);
 175 }
 176
 177 /*
 178  * Destroy the RPC credential cache
 179  */
 180 void
 181 rpcauth_destroy_credcache(struct rpc_auth *auth)
 182 {
 183         struct rpc_cred_cache *cache = auth->au_credcache;
 184
 185         if (cache) {
 186                 auth->au_credcache = NULL;
 187                 rpcauth_clear_credcache(cache);
 188                 kfree(cache);
 189         }
 190 }
 191
 192 /*
 193  * Remove stale credentials. Avoid sleeping inside the loop.
 194  */
 195 static void
 196 rpcauth_prune_expired(struct list_head *free)
 197 {
 198         struct rpc_cred *cred;
 199
 200         while (!list_empty(&cred_unused)) {
 201                 cred = list_entry(cred_unused.next, struct rpc_cred, cr_lru);
 202                 if (time_after(jiffies, cred->cr_expire +
 203                                         cred->cr_auth->au_credcache->expire))
 204                         break;
 205                 list_del_init(&cred->cr_lru);
 206                 if (atomic_read(&cred->cr_count) != 0)
 207                         continue;
 208                 get_rpccred(cred);
 209                 list_add_tail(&cred->cr_lru, free);
 210                 smp_wmb();
 211                 hlist_del_init(&cred->cr_hash);
 212         }
 213 }
 214
 215 /*
 216  * Run garbage collector.
 217  */
 218 static void
 219 rpcauth_gc_credcache(struct rpc_cred_cache *cache, struct list_head *free)
 220 {
 221         if (time_before(jiffies, cache->nextgc))
 222                 return;
 223         cache->nextgc = jiffies + cache->expire;
 224         rpcauth_prune_expired(free);
 225 }
 226
 227 /*
 228  * Look up a process' credentials in the authentication cache
 229  */
 230 struct rpc_cred *
 231 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 232                 int flags)
 233 {
 234         LIST_HEAD(free);
 235         struct rpc_cred_cache *cache = auth->au_credcache;
 236         struct hlist_node *pos;
 237         struct rpc_cred *new = NULL,
 238                         *cred = NULL,
 239                         *entry;
 240         int             nr = 0;
 241
 242         if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
 243                 nr = acred->uid & RPC_CREDCACHE_MASK;
 244 retry:
 245         spin_lock(&rpc_credcache_lock);
 246         hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
 247                 if (!entry->cr_ops->crmatch(acred, entry, flags))
 248                         continue;
 249                 cred = get_rpccred(entry);
 250                 hlist_del(&entry->cr_hash);
 251                 break;
 252         }
 253         if (new) {
 254                 if (cred)
 255                         list_add_tail(&new->cr_lru, &free);
 256                 else
 257                         cred = new;
 258         }
 259         if (cred) {
 260                 hlist_add_head(&cred->cr_hash, &cache->hashtable[nr]);
 261         }
 262         rpcauth_gc_credcache(cache, &free);
 263         spin_unlock(&rpc_credcache_lock);
 264
 265         rpcauth_destroy_credlist(&free);
 266
 267         if (!cred) {
 268                 new = auth->au_ops->crcreate(auth, acred, flags);
 269                 if (!IS_ERR(new))
 270                         goto retry;
 271                 cred = new;
 272         } else if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags)
 273                         && cred->cr_ops->cr_init != NULL
 274                         && !(flags & RPCAUTH_LOOKUP_NEW)) {
 275                 int res = cred->cr_ops->cr_init(auth, cred);
 276                 if (res < 0) {
 277                         put_rpccred(cred);
 278                         cred = ERR_PTR(res);
 279                 }
 280         }
 281
 282         return (struct rpc_cred *) cred;
 283 }
 284
 285 struct rpc_cred *
 286 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 287 {
 288         struct auth_cred acred = {
 289                 .uid = current->fsuid,
 290                 .gid = current->fsgid,
 291                 .group_info = current->group_info,
 292         };
 293         struct rpc_cred *ret;
 294
 295         dprintk("RPC:       looking up %s cred\n",
 296                 auth->au_ops->au_name);
 297         get_group_info(acred.group_info);
 298         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 299         put_group_info(acred.group_info);
 300         return ret;
 301 }
 302
 303 void
 304 rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 305                   struct rpc_auth *auth, const struct rpc_credops *ops)
 306 {
 307         INIT_HLIST_NODE(&cred->cr_hash);
 308         INIT_LIST_HEAD(&cred->cr_lru);
 309         atomic_set(&cred->cr_count, 1);
 310         cred->cr_auth = auth;
 311         cred->cr_ops = ops;
 312         cred->cr_expire = jiffies;
 313 #ifdef RPC_DEBUG
 314         cred->cr_magic = RPCAUTH_CRED_MAGIC;
 315 #endif
 316         cred->cr_uid = acred->uid;
 317 }
 318 EXPORT_SYMBOL(rpcauth_init_cred);
 319
 320 struct rpc_cred *
 321 rpcauth_bindcred(struct rpc_task *task)
 322 {
 323         struct rpc_auth *auth = task->tk_auth;
 324         struct auth_cred acred = {
 325                 .uid = current->fsuid,
 326                 .gid = current->fsgid,
 327                 .group_info = current->group_info,
 328         };
 329         struct rpc_cred *ret;
 330         int flags = 0;
 331
 332         dprintk("RPC: %5u looking up %s cred\n",
 333                 task->tk_pid, task->tk_auth->au_ops->au_name);
 334         get_group_info(acred.group_info);
 335         if (task->tk_flags & RPC_TASK_ROOTCREDS)
 336                 flags |= RPCAUTH_LOOKUP_ROOTCREDS;
 337         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 338         if (!IS_ERR(ret))
 339                 task->tk_msg.rpc_cred = ret;
 340         else
 341                 task->tk_status = PTR_ERR(ret);
 342         put_group_info(acred.group_info);
 343         return ret;
 344 }
 345
 346 void
 347 rpcauth_holdcred(struct rpc_task *task)
 348 {
 349         dprintk("RPC: %5u holding %s cred %p\n",
 350                 task->tk_pid, task->tk_auth->au_ops->au_name,
 351                 task->tk_msg.rpc_cred);
 352         if (task->tk_msg.rpc_cred)
 353                 get_rpccred(task->tk_msg.rpc_cred);
 354 }
 355
 356 void
 357 put_rpccred(struct rpc_cred *cred)
 358 {
 359         /* Fast path for unhashed credentials */
 360         if (!hlist_unhashed(&cred->cr_hash))
 361                 goto need_lock;
 362
 363         if (!atomic_dec_and_test(&cred->cr_count))
 364                 return;
 365         goto out_destroy;
 366
 367 need_lock:
 368         if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
 369                 return;
 370         if (!list_empty(&cred->cr_lru))
 371                 list_del_init(&cred->cr_lru);
 372         if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) == 0)
 373                 hlist_del(&cred->cr_hash);
 374         else if (!hlist_unhashed(&cred->cr_hash)) {
 375                 cred->cr_expire = jiffies;
 376                 list_add_tail(&cred->cr_lru, &cred_unused);
 377                 spin_unlock(&rpc_credcache_lock);
 378                 return;
 379         }
 380         spin_unlock(&rpc_credcache_lock);
 381 out_destroy:
 382         cred->cr_ops->crdestroy(cred);
 383 }
 384
 385 void
 386 rpcauth_unbindcred(struct rpc_task *task)
 387 {
 388         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 389
 390         dprintk("RPC: %5u releasing %s cred %p\n",
 391                 task->tk_pid, task->tk_auth->au_ops->au_name, cred);
 392
 393         put_rpccred(cred);
 394         task->tk_msg.rpc_cred = NULL;
 395 }
 396
 397 __be32 *
 398 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
 399 {
 400         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 401
 402         dprintk("RPC: %5u marshaling %s cred %p\n",
 403                 task->tk_pid, task->tk_auth->au_ops->au_name, cred);
 404
 405         return cred->cr_ops->crmarshal(task, p);
 406 }
 407
 408 __be32 *
 409 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
 410 {
 411         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 412
 413         dprintk("RPC: %5u validating %s cred %p\n",
 414                 task->tk_pid, task->tk_auth->au_ops->au_name, cred);
 415
 416         return cred->cr_ops->crvalidate(task, p);
 417 }
 418
 419 int
 420 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
 421                 __be32 *data, void *obj)
 422 {
 423         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 424
 425         dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
 426                         task->tk_pid, cred->cr_ops->cr_name, cred);
 427         if (cred->cr_ops->crwrap_req)
 428                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
 429         /* By default, we encode the arguments normally. */
 430         return encode(rqstp, data, obj);
 431 }
 432
 433 int
 434 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
 435                 __be32 *data, void *obj)
 436 {
 437         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 438
 439         dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
 440                         task->tk_pid, cred->cr_ops->cr_name, cred);
 441         if (cred->cr_ops->crunwrap_resp)
 442                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
 443                                                    data, obj);
 444         /* By default, we decode the arguments normally. */
 445         return decode(rqstp, data, obj);
 446 }
 447
 448 int
 449 rpcauth_refreshcred(struct rpc_task *task)
 450 {
 451         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 452         int err;
 453
 454         dprintk("RPC: %5u refreshing %s cred %p\n",
 455                 task->tk_pid, task->tk_auth->au_ops->au_name, cred);
 456
 457         err = cred->cr_ops->crrefresh(task);
 458         if (err < 0)
 459                 task->tk_status = err;
 460         return err;
 461 }
 462
 463 void
 464 rpcauth_invalcred(struct rpc_task *task)
 465 {
 466         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 467
 468         dprintk("RPC: %5u invalidating %s cred %p\n",
 469                 task->tk_pid, task->tk_auth->au_ops->au_name, cred);
 470         if (cred)
 471                 clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 472 }
 473
 474 int
 475 rpcauth_uptodatecred(struct rpc_task *task)
 476 {
 477         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 478
 479         return cred == NULL ||
 480                 test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 481 }