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 struct rpc_authops *     auth_flavors[RPC_AUTH_MAXFLAVOR] = {
  22         &authnull_ops,          /* AUTH_NULL */
  23         &authunix_ops,          /* AUTH_UNIX */
  24         NULL,                   /* others can be loadable modules */
  25 };
  26
  27 static u32
  28 pseudoflavor_to_flavor(u32 flavor) {
  29         if (flavor >= RPC_AUTH_MAXFLAVOR)
  30                 return RPC_AUTH_GSS;
  31         return flavor;
  32 }
  33
  34 int
  35 rpcauth_register(struct rpc_authops *ops)
  36 {
  37         rpc_authflavor_t flavor;
  38
  39         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
  40                 return -EINVAL;
  41         if (auth_flavors[flavor] != NULL)
  42                 return -EPERM;          /* what else? */
  43         auth_flavors[flavor] = ops;
  44         return 0;
  45 }
  46
  47 int
  48 rpcauth_unregister(struct rpc_authops *ops)
  49 {
  50         rpc_authflavor_t flavor;
  51
  52         if ((flavor = ops->au_flavor) >= RPC_AUTH_MAXFLAVOR)
  53                 return -EINVAL;
  54         if (auth_flavors[flavor] != ops)
  55                 return -EPERM;          /* what else? */
  56         auth_flavors[flavor] = NULL;
  57         return 0;
  58 }
  59
  60 struct rpc_auth *
  61 rpcauth_create(rpc_authflavor_t pseudoflavor, struct rpc_clnt *clnt)
  62 {
  63         struct rpc_auth         *auth;
  64         struct rpc_authops      *ops;
  65         u32                     flavor = pseudoflavor_to_flavor(pseudoflavor);
  66
  67         auth = ERR_PTR(-EINVAL);
  68         if (flavor >= RPC_AUTH_MAXFLAVOR)
  69                 goto out;
  70
  71         /* FIXME - auth_flavors[] really needs an rw lock,
  72          * and module refcounting. */
  73 #ifdef CONFIG_KMOD
  74         if ((ops = auth_flavors[flavor]) == NULL)
  75                 request_module("rpc-auth-%u", flavor);
  76 #endif
  77         if ((ops = auth_flavors[flavor]) == NULL)
  78                 goto out;
  79         auth = ops->create(clnt, pseudoflavor);
  80         if (IS_ERR(auth))
  81                 return auth;
  82         if (clnt->cl_auth)
  83                 rpcauth_destroy(clnt->cl_auth);
  84         clnt->cl_auth = auth;
  85
  86 out:
  87         return auth;
  88 }
  89
  90 void
  91 rpcauth_destroy(struct rpc_auth *auth)
  92 {
  93         if (!atomic_dec_and_test(&auth->au_count))
  94                 return;
  95         auth->au_ops->destroy(auth);
  96 }
  97
  98 static DEFINE_SPINLOCK(rpc_credcache_lock);
  99
 100 /*
 101  * Initialize RPC credential cache
 102  */
 103 int
 104 rpcauth_init_credcache(struct rpc_auth *auth, unsigned long expire)
 105 {
 106         struct rpc_cred_cache *new;
 107         int i;
 108
 109         new = kmalloc(sizeof(*new), GFP_KERNEL);
 110         if (!new)
 111                 return -ENOMEM;
 112         for (i = 0; i < RPC_CREDCACHE_NR; i++)
 113                 INIT_HLIST_HEAD(&new->hashtable[i]);
 114         new->expire = expire;
 115         new->nextgc = jiffies + (expire >> 1);
 116         auth->au_credcache = new;
 117         return 0;
 118 }
 119
 120 /*
 121  * Destroy a list of credentials
 122  */
 123 static inline
 124 void rpcauth_destroy_credlist(struct hlist_head *head)
 125 {
 126         struct rpc_cred *cred;
 127
 128         while (!hlist_empty(head)) {
 129                 cred = hlist_entry(head->first, struct rpc_cred, cr_hash);
 130                 hlist_del_init(&cred->cr_hash);
 131                 put_rpccred(cred);
 132         }
 133 }
 134
 135 /*
 136  * Clear the RPC credential cache, and delete those credentials
 137  * that are not referenced.
 138  */
 139 void
 140 rpcauth_free_credcache(struct rpc_auth *auth)
 141 {
 142         struct rpc_cred_cache *cache = auth->au_credcache;
 143         HLIST_HEAD(free);
 144         struct hlist_node *pos, *next;
 145         struct rpc_cred *cred;
 146         int             i;
 147
 148         spin_lock(&rpc_credcache_lock);
 149         for (i = 0; i < RPC_CREDCACHE_NR; i++) {
 150                 hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
 151                         cred = hlist_entry(pos, struct rpc_cred, cr_hash);
 152                         __hlist_del(&cred->cr_hash);
 153                         hlist_add_head(&cred->cr_hash, &free);
 154                 }
 155         }
 156         spin_unlock(&rpc_credcache_lock);
 157         rpcauth_destroy_credlist(&free);
 158 }
 159
 160 static void
 161 rpcauth_prune_expired(struct rpc_auth *auth, struct rpc_cred *cred, struct hlist_head *free)
 162 {
 163         if (atomic_read(&cred->cr_count) != 1)
 164                return;
 165         if (time_after(jiffies, cred->cr_expire + auth->au_credcache->expire))
 166                 cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
 167         if (!(cred->cr_flags & RPCAUTH_CRED_UPTODATE)) {
 168                 __hlist_del(&cred->cr_hash);
 169                 hlist_add_head(&cred->cr_hash, free);
 170         }
 171 }
 172
 173 /*
 174  * Remove stale credentials. Avoid sleeping inside the loop.
 175  */
 176 static void
 177 rpcauth_gc_credcache(struct rpc_auth *auth, struct hlist_head *free)
 178 {
 179         struct rpc_cred_cache *cache = auth->au_credcache;
 180         struct hlist_node *pos, *next;
 181         struct rpc_cred *cred;
 182         int             i;
 183
 184         dprintk("RPC: gc'ing RPC credentials for auth %p\n", auth);
 185         for (i = 0; i < RPC_CREDCACHE_NR; i++) {
 186                 hlist_for_each_safe(pos, next, &cache->hashtable[i]) {
 187                         cred = hlist_entry(pos, struct rpc_cred, cr_hash);
 188                         rpcauth_prune_expired(auth, cred, free);
 189                 }
 190         }
 191         cache->nextgc = jiffies + cache->expire;
 192 }
 193
 194 /*
 195  * Look up a process' credentials in the authentication cache
 196  */
 197 struct rpc_cred *
 198 rpcauth_lookup_credcache(struct rpc_auth *auth, struct auth_cred * acred,
 199                 int flags)
 200 {
 201         struct rpc_cred_cache *cache = auth->au_credcache;
 202         HLIST_HEAD(free);
 203         struct hlist_node *pos, *next;
 204         struct rpc_cred *new = NULL,
 205                         *cred = NULL;
 206         int             nr = 0;
 207
 208         if (!(flags & RPCAUTH_LOOKUP_ROOTCREDS))
 209                 nr = acred->uid & RPC_CREDCACHE_MASK;
 210 retry:
 211         spin_lock(&rpc_credcache_lock);
 212         if (time_before(cache->nextgc, jiffies))
 213                 rpcauth_gc_credcache(auth, &free);
 214         hlist_for_each_safe(pos, next, &cache->hashtable[nr]) {
 215                 struct rpc_cred *entry;
 216                 entry = hlist_entry(pos, struct rpc_cred, cr_hash);
 217                 if (entry->cr_ops->crmatch(acred, entry, flags)) {
 218                         hlist_del(&entry->cr_hash);
 219                         cred = entry;
 220                         break;
 221                 }
 222                 rpcauth_prune_expired(auth, entry, &free);
 223         }
 224         if (new) {
 225                 if (cred)
 226                         hlist_add_head(&new->cr_hash, &free);
 227                 else
 228                         cred = new;
 229         }
 230         if (cred) {
 231                 hlist_add_head(&cred->cr_hash, &cache->hashtable[nr]);
 232                 get_rpccred(cred);
 233         }
 234         spin_unlock(&rpc_credcache_lock);
 235
 236         rpcauth_destroy_credlist(&free);
 237
 238         if (!cred) {
 239                 new = auth->au_ops->crcreate(auth, acred, flags);
 240                 if (!IS_ERR(new)) {
 241 #ifdef RPC_DEBUG
 242                         new->cr_magic = RPCAUTH_CRED_MAGIC;
 243 #endif
 244                         goto retry;
 245                 } else
 246                         cred = new;
 247         } else if ((cred->cr_flags & RPCAUTH_CRED_NEW)
 248                         && cred->cr_ops->cr_init != NULL
 249                         && !(flags & RPCAUTH_LOOKUP_NEW)) {
 250                 int res = cred->cr_ops->cr_init(auth, cred);
 251                 if (res < 0) {
 252                         put_rpccred(cred);
 253                         cred = ERR_PTR(res);
 254                 }
 255         }
 256
 257         return (struct rpc_cred *) cred;
 258 }
 259
 260 struct rpc_cred *
 261 rpcauth_lookupcred(struct rpc_auth *auth, int flags)
 262 {
 263         struct auth_cred acred = {
 264                 .uid = current->fsuid,
 265                 .gid = current->fsgid,
 266                 .group_info = current->group_info,
 267         };
 268         struct rpc_cred *ret;
 269
 270         dprintk("RPC:     looking up %s cred\n",
 271                 auth->au_ops->au_name);
 272         get_group_info(acred.group_info);
 273         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 274         put_group_info(acred.group_info);
 275         return ret;
 276 }
 277
 278 struct rpc_cred *
 279 rpcauth_bindcred(struct rpc_task *task)
 280 {
 281         struct rpc_auth *auth = task->tk_auth;
 282         struct auth_cred acred = {
 283                 .uid = current->fsuid,
 284                 .gid = current->fsgid,
 285                 .group_info = current->group_info,
 286         };
 287         struct rpc_cred *ret;
 288         int flags = 0;
 289
 290         dprintk("RPC: %4d looking up %s cred\n",
 291                 task->tk_pid, task->tk_auth->au_ops->au_name);
 292         get_group_info(acred.group_info);
 293         if (task->tk_flags & RPC_TASK_ROOTCREDS)
 294                 flags |= RPCAUTH_LOOKUP_ROOTCREDS;
 295         ret = auth->au_ops->lookup_cred(auth, &acred, flags);
 296         if (!IS_ERR(ret))
 297                 task->tk_msg.rpc_cred = ret;
 298         else
 299                 task->tk_status = PTR_ERR(ret);
 300         put_group_info(acred.group_info);
 301         return ret;
 302 }
 303
 304 void
 305 rpcauth_holdcred(struct rpc_task *task)
 306 {
 307         dprintk("RPC: %4d holding %s cred %p\n",
 308                 task->tk_pid, task->tk_auth->au_ops->au_name, task->tk_msg.rpc_cred);
 309         if (task->tk_msg.rpc_cred)
 310                 get_rpccred(task->tk_msg.rpc_cred);
 311 }
 312
 313 void
 314 put_rpccred(struct rpc_cred *cred)
 315 {
 316         cred->cr_expire = jiffies;
 317         if (!atomic_dec_and_test(&cred->cr_count))
 318                 return;
 319         cred->cr_ops->crdestroy(cred);
 320 }
 321
 322 void
 323 rpcauth_unbindcred(struct rpc_task *task)
 324 {
 325         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 326
 327         dprintk("RPC: %4d releasing %s cred %p\n",
 328                 task->tk_pid, task->tk_auth->au_ops->au_name, cred);
 329
 330         put_rpccred(cred);
 331         task->tk_msg.rpc_cred = NULL;
 332 }
 333
 334 __be32 *
 335 rpcauth_marshcred(struct rpc_task *task, __be32 *p)
 336 {
 337         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 338
 339         dprintk("RPC: %4d marshaling %s cred %p\n",
 340                 task->tk_pid, task->tk_auth->au_ops->au_name, cred);
 341
 342         return cred->cr_ops->crmarshal(task, p);
 343 }
 344
 345 __be32 *
 346 rpcauth_checkverf(struct rpc_task *task, __be32 *p)
 347 {
 348         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 349
 350         dprintk("RPC: %4d validating %s cred %p\n",
 351                 task->tk_pid, task->tk_auth->au_ops->au_name, cred);
 352
 353         return cred->cr_ops->crvalidate(task, p);
 354 }
 355
 356 int
 357 rpcauth_wrap_req(struct rpc_task *task, kxdrproc_t encode, void *rqstp,
 358                 __be32 *data, void *obj)
 359 {
 360         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 361
 362         dprintk("RPC: %4d using %s cred %p to wrap rpc data\n",
 363                         task->tk_pid, cred->cr_ops->cr_name, cred);
 364         if (cred->cr_ops->crwrap_req)
 365                 return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
 366         /* By default, we encode the arguments normally. */
 367         return encode(rqstp, data, obj);
 368 }
 369
 370 int
 371 rpcauth_unwrap_resp(struct rpc_task *task, kxdrproc_t decode, void *rqstp,
 372                 __be32 *data, void *obj)
 373 {
 374         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 375
 376         dprintk("RPC: %4d using %s cred %p to unwrap rpc data\n",
 377                         task->tk_pid, cred->cr_ops->cr_name, cred);
 378         if (cred->cr_ops->crunwrap_resp)
 379                 return cred->cr_ops->crunwrap_resp(task, decode, rqstp,
 380                                                    data, obj);
 381         /* By default, we decode the arguments normally. */
 382         return decode(rqstp, data, obj);
 383 }
 384
 385 int
 386 rpcauth_refreshcred(struct rpc_task *task)
 387 {
 388         struct rpc_cred *cred = task->tk_msg.rpc_cred;
 389         int err;
 390
 391         dprintk("RPC: %4d refreshing %s cred %p\n",
 392                 task->tk_pid, task->tk_auth->au_ops->au_name, cred);
 393
 394         err = cred->cr_ops->crrefresh(task);
 395         if (err < 0)
 396                 task->tk_status = err;
 397         return err;
 398 }
 399
 400 void
 401 rpcauth_invalcred(struct rpc_task *task)
 402 {
 403         dprintk("RPC: %4d invalidating %s cred %p\n",
 404                 task->tk_pid, task->tk_auth->au_ops->au_name, task->tk_msg.rpc_cred);
 405         spin_lock(&rpc_credcache_lock);
 406         if (task->tk_msg.rpc_cred)
 407                 task->tk_msg.rpc_cred->cr_flags &= ~RPCAUTH_CRED_UPTODATE;
 408         spin_unlock(&rpc_credcache_lock);
 409 }
 410
 411 int
 412 rpcauth_uptodatecred(struct rpc_task *task)
 413 {
 414         return !(task->tk_msg.rpc_cred) ||
 415                 (task->tk_msg.rpc_cred->cr_flags & RPCAUTH_CRED_UPTODATE);
 416 }