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