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