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