net/sunrpc/svcauth.c

   1 /*
   2  * linux/net/sunrpc/svcauth.c
   3  *
   4  * The generic interface for RPC authentication on the server side.
   5  *
   6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7  *
   8  * CHANGES
   9  * 19-Apr-2000 Chris Evans      - Security fix
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/sched.h>
  14 #include <linux/module.h>
  15 #include <linux/sunrpc/types.h>
  16 #include <linux/sunrpc/xdr.h>
  17 #include <linux/sunrpc/svcsock.h>
  18 #include <linux/sunrpc/svcauth.h>
  19 #include <linux/err.h>
  20 #include <linux/hash.h>
  21
  22 #define RPCDBG_FACILITY RPCDBG_AUTH
  23
  24
  25 /*
  26  * Table of authenticators
  27  */
  28 extern struct auth_ops svcauth_null;
  29 extern struct auth_ops svcauth_unix;
  30
  31 static DEFINE_SPINLOCK(authtab_lock);
  32 static struct auth_ops  *authtab[RPC_AUTH_MAXFLAVOR] = {
  33         [0] = &svcauth_null,
  34         [1] = &svcauth_unix,
  35 };
  36
  37 int
  38 svc_authenticate(struct svc_rqst *rqstp, __be32 *authp)
  39 {
  40         rpc_authflavor_t        flavor;
  41         struct auth_ops         *aops;
  42
  43         *authp = rpc_auth_ok;
  44
  45         flavor = svc_getnl(&rqstp->rq_arg.head[0]);
  46
  47         dprintk("svc: svc_authenticate (%d)\n", flavor);
  48
  49         spin_lock(&authtab_lock);
  50         if (flavor >= RPC_AUTH_MAXFLAVOR || !(aops = authtab[flavor])
  51                         || !try_module_get(aops->owner)) {
  52                 spin_unlock(&authtab_lock);
  53                 *authp = rpc_autherr_badcred;
  54                 return SVC_DENIED;
  55         }
  56         spin_unlock(&authtab_lock);
  57
  58         rqstp->rq_authop = aops;
  59         return aops->accept(rqstp, authp);
  60 }
  61
  62 int svc_set_client(struct svc_rqst *rqstp)
  63 {
  64         return rqstp->rq_authop->set_client(rqstp);
  65 }
  66
  67 /* A request, which was authenticated, has now executed.
  68  * Time to finalise the the credentials and verifier
  69  * and release and resources
  70  */
  71 int svc_authorise(struct svc_rqst *rqstp)
  72 {
  73         struct auth_ops *aops = rqstp->rq_authop;
  74         int rv = 0;
  75
  76         rqstp->rq_authop = NULL;
  77
  78         if (aops) {
  79                 rv = aops->release(rqstp);
  80                 module_put(aops->owner);
  81         }
  82         return rv;
  83 }
  84
  85 int
  86 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
  87 {
  88         int rv = -EINVAL;
  89         spin_lock(&authtab_lock);
  90         if (flavor < RPC_AUTH_MAXFLAVOR && authtab[flavor] == NULL) {
  91                 authtab[flavor] = aops;
  92                 rv = 0;
  93         }
  94         spin_unlock(&authtab_lock);
  95         return rv;
  96 }
  97
  98 void
  99 svc_auth_unregister(rpc_authflavor_t flavor)
 100 {
 101         spin_lock(&authtab_lock);
 102         if (flavor < RPC_AUTH_MAXFLAVOR)
 103                 authtab[flavor] = NULL;
 104         spin_unlock(&authtab_lock);
 105 }
 106 EXPORT_SYMBOL(svc_auth_unregister);
 107
 108 /**************************************************
 109  * 'auth_domains' are stored in a hash table indexed by name.
 110  * When the last reference to an 'auth_domain' is dropped,
 111  * the object is unhashed and freed.
 112  * If auth_domain_lookup fails to find an entry, it will return
 113  * it's second argument 'new'.  If this is non-null, it will
 114  * have been atomically linked into the table.
 115  */
 116
 117 #define DN_HASHBITS     6
 118 #define DN_HASHMAX      (1<<DN_HASHBITS)
 119 #define DN_HASHMASK     (DN_HASHMAX-1)
 120
 121 static struct hlist_head        auth_domain_table[DN_HASHMAX];
 122 static spinlock_t       auth_domain_lock =
 123         __SPIN_LOCK_UNLOCKED(auth_domain_lock);
 124
 125 void auth_domain_put(struct auth_domain *dom)
 126 {
 127         if (atomic_dec_and_lock(&dom->ref.refcount, &auth_domain_lock)) {
 128                 hlist_del(&dom->hash);
 129                 dom->flavour->domain_release(dom);
 130                 spin_unlock(&auth_domain_lock);
 131         }
 132 }
 133
 134 struct auth_domain *
 135 auth_domain_lookup(char *name, struct auth_domain *new)
 136 {
 137         struct auth_domain *hp;
 138         struct hlist_head *head;
 139         struct hlist_node *np;
 140
 141         head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
 142
 143         spin_lock(&auth_domain_lock);
 144
 145         hlist_for_each_entry(hp, np, head, hash) {
 146                 if (strcmp(hp->name, name)==0) {
 147                         kref_get(&hp->ref);
 148                         spin_unlock(&auth_domain_lock);
 149                         return hp;
 150                 }
 151         }
 152         if (new)
 153                 hlist_add_head(&new->hash, head);
 154         spin_unlock(&auth_domain_lock);
 155         return new;
 156 }
 157
 158 struct auth_domain *auth_domain_find(char *name)
 159 {
 160         return auth_domain_lookup(name, NULL);
 161 }