linux/net/sunrpc/auth.c
<<
>>
Prefs
   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
  22static DEFINE_SPINLOCK(rpc_authflavor_lock);
  23static 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
  29static LIST_HEAD(cred_unused);
  30static unsigned long number_cred_unused;
  31
  32static u32
  33pseudoflavor_to_flavor(u32 flavor) {
  34        if (flavor >= RPC_AUTH_MAXFLAVOR)
  35                return RPC_AUTH_GSS;
  36        return flavor;
  37}
  38
  39int
  40rpcauth_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}
  55EXPORT_SYMBOL_GPL(rpcauth_register);
  56
  57int
  58rpcauth_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}
  73EXPORT_SYMBOL_GPL(rpcauth_unregister);
  74
  75struct rpc_auth *
  76rpcauth_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        if ((ops = auth_flavors[flavor]) == NULL)
  87                request_module("rpc-auth-%u", flavor);
  88        spin_lock(&rpc_authflavor_lock);
  89        ops = auth_flavors[flavor];
  90        if (ops == NULL || !try_module_get(ops->owner)) {
  91                spin_unlock(&rpc_authflavor_lock);
  92                goto out;
  93        }
  94        spin_unlock(&rpc_authflavor_lock);
  95        auth = ops->create(clnt, pseudoflavor);
  96        module_put(ops->owner);
  97        if (IS_ERR(auth))
  98                return auth;
  99        if (clnt->cl_auth)
 100                rpcauth_release(clnt->cl_auth);
 101        clnt->cl_auth = auth;
 102
 103out:
 104        return auth;
 105}
 106EXPORT_SYMBOL_GPL(rpcauth_create);
 107
 108void
 109rpcauth_release(struct rpc_auth *auth)
 110{
 111        if (!atomic_dec_and_test(&auth->au_count))
 112                return;
 113        auth->au_ops->destroy(auth);
 114}
 115
 116static DEFINE_SPINLOCK(rpc_credcache_lock);
 117
 118static void
 119rpcauth_unhash_cred_locked(struct rpc_cred *cred)
 120{
 121        hlist_del_rcu(&cred->cr_hash);
 122        smp_mb__before_clear_bit();
 123        clear_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 124}
 125
 126static int
 127rpcauth_unhash_cred(struct rpc_cred *cred)
 128{
 129        spinlock_t *cache_lock;
 130        int ret;
 131
 132        cache_lock = &cred->cr_auth->au_credcache->lock;
 133        spin_lock(cache_lock);
 134        ret = atomic_read(&cred->cr_count) == 0;
 135        if (ret)
 136                rpcauth_unhash_cred_locked(cred);
 137        spin_unlock(cache_lock);
 138        return ret;
 139}
 140
 141/*
 142 * Initialize RPC credential cache
 143 */
 144int
 145rpcauth_init_credcache(struct rpc_auth *auth)
 146{
 147        struct rpc_cred_cache *new;
 148        int i;
 149
 150        new = kmalloc(sizeof(*new), GFP_KERNEL);
 151        if (!new)
 152                return -ENOMEM;
 153        for (i = 0; i < RPC_CREDCACHE_NR; i++)
 154                INIT_HLIST_HEAD(&new->hashtable[i]);
 155        spin_lock_init(&new->lock);
 156        auth->au_credcache = new;
 157        return 0;
 158}
 159EXPORT_SYMBOL_GPL(rpcauth_init_credcache);
 160
 161/*
 162 * Destroy a list of credentials
 163 */
 164static inline
 165void rpcauth_destroy_credlist(struct list_head *head)
 166{
 167        struct rpc_cred *cred;
 168
 169        while (!list_empty(head)) {
 170                cred = list_entry(head->next, struct rpc_cred, cr_lru);
 171                list_del_init(&cred->cr_lru);
 172                put_rpccred(cred);
 173        }
 174}
 175
 176/*
 177 * Clear the RPC credential cache, and delete those credentials
 178 * that are not referenced.
 179 */
 180void
 181rpcauth_clear_credcache(struct rpc_cred_cache *cache)
 182{
 183        LIST_HEAD(free);
 184        struct hlist_head *head;
 185        struct rpc_cred *cred;
 186        int             i;
 187
 188        spin_lock(&rpc_credcache_lock);
 189        spin_lock(&cache->lock);
 190        for (i = 0; i < RPC_CREDCACHE_NR; i++) {
 191                head = &cache->hashtable[i];
 192                while (!hlist_empty(head)) {
 193                        cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
 194                        get_rpccred(cred);
 195                        if (!list_empty(&cred->cr_lru)) {
 196                                list_del(&cred->cr_lru);
 197                                number_cred_unused--;
 198                        }
 199                        list_add_tail(&cred->cr_lru, &free);
 200                        rpcauth_unhash_cred_locked(cred);
 201                }
 202        }
 203        spin_unlock(&cache->lock);
 204        spin_unlock(&rpc_credcache_lock);
 205        rpcauth_destroy_credlist(&free);
 206}
 207
 208/*
 209 * Destroy the RPC credential cache
 210 */
 211void
 212rpcauth_destroy_credcache(struct rpc_auth *auth)
 213{
 214        struct rpc_cred_cache *cache = auth->au_credcache;
 215
 216        if (cache) {
 217                auth->au_credcache = NULL;
 218                rpcauth_clear_credcache(cache);
 219                kfree(cache);
 220        }
 221}
 222EXPORT_SYMBOL_GPL(rpcauth_destroy_credcache);
 223
 224
 225#define RPC_AUTH_EXPIRY_MORATORIUM (60 * HZ)
 226
 227/*
 228 * Remove stale credentials. Avoid sleeping inside the loop.
 229 */
 230static int
 231rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
 232{
 233        spinlock_t *cache_lock;
 234        struct rpc_cred *cred, *next;
 235        unsigned long expired = jiffies - RPC_AUTH_EXPIRY_MORATORIUM;
 236
 237        list_for_each_entry_safe(cred, next, &cred_unused, cr_lru) {
 238
 239                if (nr_to_scan-- == 0)
 240                        break;
 241                /*
 242                 * Enforce a 60 second garbage collection moratorium
 243                 * Note that the cred_unused list must be time-ordered.
 244                 */
 245                if (time_in_range(cred->cr_expire, expired, jiffies) &&
 246                    test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0)
 247                        return 0;
 248
 249                list_del_init(&cred->cr_lru);
 250                number_cred_unused--;
 251                if (atomic_read(&cred->cr_count) != 0)
 252                        continue;
 253
 254                cache_lock = &cred->cr_auth->au_credcache->lock;
 255                spin_lock(cache_lock);
 256                if (atomic_read(&cred->cr_count) == 0) {
 257                        get_rpccred(cred);
 258                        list_add_tail(&cred->cr_lru, free);
 259                        rpcauth_unhash_cred_locked(cred);
 260                }
 261                spin_unlock(cache_lock);
 262        }
 263        return (number_cred_unused / 100) * sysctl_vfs_cache_pressure;
 264}
 265
 266/*
 267 * Run memory cache shrinker.
 268 */
 269static int
 270rpcauth_cache_shrinker(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
 271{
 272        LIST_HEAD(free);
 273        int res;
 274
 275        if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
 276                return (nr_to_scan == 0) ? 0 : -1;
 277        if (list_empty(&cred_unused))
 278                return 0;
 279        spin_lock(&rpc_credcache_lock);
 280        res = rpcauth_prune_expired(&free, nr_to_scan);
 281        spin_unlock(&rpc_credcache_lock);
 282        rpcauth_destroy_credlist(&free);
 283        return res;
 284}
 285
 286/*
 287 * Look up a process' credentials in the authentication cache
 288 */
 289struct rpc_cred *
 290rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 291                int flags)
 292{
 293        LIST_HEAD(free);
 294        struct rpc_cred_cache *cache = auth->au_credcache;
 295        struct hlist_node *pos;
 296        struct rpc_cred *cred = NULL,
 297                        *entry, *new;
 298        unsigned int nr;
 299
 300        nr = hash_long(acred->uid, RPC_CREDCACHE_HASHBITS);
 301
 302        rcu_read_lock();
 303        hlist_for_each_entry_rcu(entry, pos, &cache->hashtable[nr], cr_hash) {
 304                if (!entry->cr_ops->crmatch(acred, entry, flags))
 305                        continue;
 306                spin_lock(&cache->lock);
 307                if (test_bit(RPCAUTH_CRED_HASHED, &entry->cr_flags) == 0) {
 308                        spin_unlock(&cache->lock);
 309                        continue;
 310                }
 311                cred = get_rpccred(entry);
 312                spin_unlock(&cache->lock);
 313                break;
 314        }
 315        rcu_read_unlock();
 316
 317        if (cred != NULL)
 318                goto found;
 319
 320        new = auth->au_ops->crcreate(auth, acred, flags);
 321        if (IS_ERR(new)) {
 322                cred = new;
 323                goto out;
 324        }
 325
 326        spin_lock(&cache->lock);
 327        hlist_for_each_entry(entry, pos, &cache->hashtable[nr], cr_hash) {
 328                if (!entry->cr_ops->crmatch(acred, entry, flags))
 329                        continue;
 330                cred = get_rpccred(entry);
 331                break;
 332        }
 333        if (cred == NULL) {
 334                cred = new;
 335                set_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags);
 336                hlist_add_head_rcu(&cred->cr_hash, &cache->hashtable[nr]);
 337        } else
 338                list_add_tail(&new->cr_lru, &free);
 339        spin_unlock(&cache->lock);
 340found:
 341        if (test_bit(RPCAUTH_CRED_NEW, &cred->cr_flags) &&
 342            cred->cr_ops->cr_init != NULL &&
 343            !(flags & RPCAUTH_LOOKUP_NEW)) {
 344                int res = cred->cr_ops->cr_init(auth, cred);
 345                if (res < 0) {
 346                        put_rpccred(cred);
 347                        cred = ERR_PTR(res);
 348                }
 349        }
 350        rpcauth_destroy_credlist(&free);
 351out:
 352        return cred;
 353}
 354EXPORT_SYMBOL_GPL(rpcauth_lookup_credcache);
 355
 356struct rpc_cred *
 357rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 358{
 359        struct auth_cred acred;
 360        struct rpc_cred *ret;
 361        const struct cred *cred = current_cred();
 362
 363        dprintk("RPC:       looking up %s cred\n",
 364                auth->au_ops->au_name);
 365
 366        memset(&acred, 0, sizeof(acred));
 367        acred.uid = cred->fsuid;
 368        acred.gid = cred->fsgid;
 369        acred.group_info = get_group_info(((struct cred *)cred)->group_info);
 370
 371        ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 372        put_group_info(acred.group_info);
 373        return ret;
 374}
 375
 376void
 377rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
 378                  struct rpc_auth *auth, const struct rpc_credops *ops)
 379{
 380        INIT_HLIST_NODE(&cred->cr_hash);
 381        INIT_LIST_HEAD(&cred->cr_lru);
 382        atomic_set(&cred->cr_count, 1);
 383        cred->cr_auth = auth;
 384        cred->cr_ops = ops;
 385        cred->cr_expire = jiffies;
 386#ifdef RPC_DEBUG
 387        cred->cr_magic = RPCAUTH_CRED_MAGIC;
 388#endif
 389        cred->cr_uid = acred->uid;
 390}
 391EXPORT_SYMBOL_GPL(rpcauth_init_cred);
 392
 393void
 394rpcauth_generic_bind_cred(struct rpc_task *task, struct rpc_cred *cred, int lookupflags)
 395{
 396        task->tk_msg.rpc_cred = get_rpccred(cred);
 397        dprintk("RPC: %5u holding %s cred %p\n", task->tk_pid,
 398                        cred->cr_auth->au_ops->au_name, cred);
 399}
 400EXPORT_SYMBOL_GPL(rpcauth_generic_bind_cred);
 401
 402static void
 403rpcauth_bind_root_cred(struct rpc_task *task, int lookupflags)
 404{
 405        struct rpc_auth *auth = task->tk_client->cl_auth;
 406        struct auth_cred acred = {
 407                .uid = 0,
 408                .gid = 0,
 409        };
 410        struct rpc_cred *ret;
 411
 412        dprintk("RPC: %5u looking up %s cred\n",
 413                task->tk_pid, task->tk_client->cl_auth->au_ops->au_name);
 414        ret = auth->au_ops->lookup_cred(auth, &acred, lookupflags);
 415        if (!IS_ERR(ret))
 416                task->tk_msg.rpc_cred = ret;
 417        else
 418                task->tk_status = PTR_ERR(ret);
 419}
 420
 421static void
 422rpcauth_bind_new_cred(struct rpc_task *task, int lookupflags)
 423{
 424        struct rpc_auth *auth = task->tk_client->cl_auth;
 425        struct rpc_cred *ret;
 426
 427        dprintk("RPC: %5u looking up %s cred\n",
 428                task->tk_pid, auth->au_ops->au_name);
 429        ret = rpcauth_lookupcred(auth, lookupflags);
 430        if (!IS_ERR(ret))
 431                task->tk_msg.rpc_cred = ret;
 432        else
 433                task->tk_status = PTR_ERR(ret);
 434}
 435
 436void
 437rpcauth_bindcred(struct rpc_task *task, struct rpc_cred *cred, int flags)
 438{
 439        int lookupflags = 0;
 440
 441        if (flags & RPC_TASK_ASYNC)
 442                lookupflags |= RPCAUTH_LOOKUP_NEW;
 443        if (cred != NULL)
 444                cred->cr_ops->crbind(task, cred, lookupflags);
 445        else if (flags & RPC_TASK_ROOTCREDS)
 446                rpcauth_bind_root_cred(task, lookupflags);
 447        else
 448                rpcauth_bind_new_cred(task, lookupflags);
 449}
 450
 451void
 452put_rpccred(struct rpc_cred *cred)
 453{
 454        /* Fast path for unhashed credentials */
 455        if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) == 0) {
 456                if (atomic_dec_and_test(&cred->cr_count))
 457                        cred->cr_ops->crdestroy(cred);
 458                return;
 459        }
 460
 461        if (!atomic_dec_and_lock(&cred->cr_count, &rpc_credcache_lock))
 462                return;
 463        if (!list_empty(&cred->cr_lru)) {
 464                number_cred_unused--;
 465                list_del_init(&cred->cr_lru);
 466        }
 467        if (test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
 468                if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0) {
 469                        cred->cr_expire = jiffies;
 470                        list_add_tail(&cred->cr_lru, &cred_unused);
 471                        number_cred_unused++;
 472                        goto out_nodestroy;
 473                }
 474                if (!rpcauth_unhash_cred(cred)) {
 475                        /* We were hashed and someone looked us up... */
 476                        goto out_nodestroy;
 477                }
 478        }
 479        spin_unlock(&rpc_credcache_lock);
 480        cred->cr_ops->crdestroy(cred);
 481        return;
 482out_nodestroy:
 483        spin_unlock(&rpc_credcache_lock);
 484}
 485EXPORT_SYMBOL_GPL(put_rpccred);
 486
 487void
 488rpcauth_unbindcred(struct rpc_task *task)
 489{
 490        struct rpc_cred *cred = task->tk_msg.rpc_cred;
 491
 492        dprintk("RPC: %5u releasing %s cred %p\n",
 493                task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 494
 495        put_rpccred(cred);
 496        task->tk_msg.rpc_cred = NULL;
 497}
 498
 499__be32 *
 500rpcauth_marshcred(struct rpc_task *task, __be32 *p)
 501{
 502        struct rpc_cred *cred = task->tk_msg.rpc_cred;
 503
 504        dprintk("RPC: %5u marshaling %s cred %p\n",
 505                task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 506
 507        return cred->cr_ops->crmarshal(task, p);
 508}
 509
 510__be32 *
 511rpcauth_checkverf(struct rpc_task *task, __be32 *p)
 512{
 513        struct rpc_cred *cred = task->tk_msg.rpc_cred;
 514
 515        dprintk("RPC: %5u validating %s cred %p\n",
 516                task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 517
 518        return cred->cr_ops->crvalidate(task, p);
 519}
 520
 521int
 522rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
 523                __be32 *data, void *obj)
 524{
 525        struct rpc_cred *cred = task->tk_msg.rpc_cred;
 526
 527        dprintk("RPC: %5u using %s cred %p to wrap rpc data\n",
 528                        task->tk_pid, cred->cr_ops->cr_name, cred);
 529        if (cred->cr_ops->crwrap_req)
 530                return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
 531        /* By default, we encode the arguments normally. */
 532        return encode(rqstp, data, obj);
 533}
 534
 535int
 536rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
 537                __be32 *data, void *obj)
 538{
 539        struct rpc_cred *cred = task->tk_msg.rpc_cred;
 540
 541        dprintk("RPC: %5u using %s cred %p to unwrap rpc data\n",
 542                        task->tk_pid, cred->cr_ops->cr_name, cred);
 543        if (cred->cr_ops->crunwrap_resp)
 544                return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
 545                                                   data, obj);
 546        /* By default, we decode the arguments normally. */
 547        return decode(rqstp, data, obj);
 548}
 549
 550int
 551rpcauth_refreshcred(struct rpc_task *task)
 552{
 553        struct rpc_cred *cred = task->tk_msg.rpc_cred;
 554        int err;
 555
 556        dprintk("RPC: %5u refreshing %s cred %p\n",
 557                task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 558
 559        err = cred->cr_ops->crrefresh(task);
 560        if (err < 0)
 561                task->tk_status = err;
 562        return err;
 563}
 564
 565void
 566rpcauth_invalcred(struct rpc_task *task)
 567{
 568        struct rpc_cred *cred = task->tk_msg.rpc_cred;
 569
 570        dprintk("RPC: %5u invalidating %s cred %p\n",
 571                task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
 572        if (cred)
 573                clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
 574}
 575
 576int
 577rpcauth_uptodatecred(struct rpc_task *task)
 578{
 579        struct rpc_cred *cred = task->tk_msg.rpc_cred;
 580
 581        return cred == NULL ||
 582                test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
 583}
 584
 585static struct shrinker rpc_cred_shrinker = {
 586        .shrink = rpcauth_cache_shrinker,
 587        .seeks = DEFAULT_SEEKS,
 588};
 589
 590void __init rpcauth_init_module(void)
 591{
 592        rpc_init_authunix();
 593        rpc_init_generic_auth();
 594        register_shrinker(&rpc_cred_shrinker);
 595}
 596
 597void __exit rpcauth_remove_module(void)
 598{
 599        unregister_shrinker(&rpc_cred_shrinker);
 600}
 601