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/module.h>
  14 #include <linux/sunrpc/types.h>
  15 #include <linux/sunrpc/xdr.h>
  16 #include <linux/sunrpc/svcsock.h>
  17 #include <linux/sunrpc/svcauth.h>
  18 #include <linux/err.h>
  19 #include <linux/hash.h>
  20
  21 #define RPCDBG_FACILITY RPCDBG_AUTH
  22
  23
  24 /*
  25  * Table of authenticators
  26  */
  27 extern struct auth_ops svcauth_null;
  28 extern struct auth_ops svcauth_unix;
  29
  30 static DEFINE_SPINLOCK(authtab_lock);
  31 static struct auth_ops  *authtab[RPC_AUTH_MAXFLAVOR] = {
  32         [0] = &svcauth_null,
  33         [1] = &svcauth_unix,
  34 };
  35
  36 int
  37 svc_authenticate(struct svc_rqst *rqstp, __be32 *authp)
  38 {
  39         rpc_authflavor_t        flavor;
  40         struct auth_ops         *aops;
  41
  42         *authp = rpc_auth_ok;
  43
  44         flavor = svc_getnl(&rqstp->rq_arg.head[0]);
  45
  46         dprintk("svc: svc_authenticate (%d)\n", flavor);
  47
  48         spin_lock(&authtab_lock);
  49         if (flavor >= RPC_AUTH_MAXFLAVOR || !(aops = authtab[flavor]) ||
  50             !try_module_get(aops->owner)) {
  51                 spin_unlock(&authtab_lock);
  52                 *authp = rpc_autherr_badcred;
  53                 return SVC_DENIED;
  54         }
  55         spin_unlock(&authtab_lock);
  56
  57         rqstp->rq_auth_slack = 0;
  58         init_svc_cred(&rqstp->rq_cred);
  59
  60         rqstp->rq_authop = aops;
  61         return aops->accept(rqstp, authp);
  62 }
  63 EXPORT_SYMBOL_GPL(svc_authenticate);
  64
  65 int svc_set_client(struct svc_rqst *rqstp)
  66 {
  67         rqstp->rq_client = NULL;
  68         return rqstp->rq_authop->set_client(rqstp);
  69 }
  70 EXPORT_SYMBOL_GPL(svc_set_client);
  71
  72 /* A request, which was authenticated, has now executed.
  73  * Time to finalise the credentials and verifier
  74  * and release and resources
  75  */
  76 int svc_authorise(struct svc_rqst *rqstp)
  77 {
  78         struct auth_ops *aops = rqstp->rq_authop;
  79         int rv = 0;
  80
  81         rqstp->rq_authop = NULL;
  82
  83         if (aops) {
  84                 rv = aops->release(rqstp);
  85                 module_put(aops->owner);
  86         }
  87         return rv;
  88 }
  89
  90 int
  91 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
  92 {
  93         int rv = -EINVAL;
  94         spin_lock(&authtab_lock);
  95         if (flavor < RPC_AUTH_MAXFLAVOR && authtab[flavor] == NULL) {
  96                 authtab[flavor] = aops;
  97                 rv = 0;
  98         }
  99         spin_unlock(&authtab_lock);
 100         return rv;
 101 }
 102 EXPORT_SYMBOL_GPL(svc_auth_register);
 103
 104 void
 105 svc_auth_unregister(rpc_authflavor_t flavor)
 106 {
 107         spin_lock(&authtab_lock);
 108         if (flavor < RPC_AUTH_MAXFLAVOR)
 109                 authtab[flavor] = NULL;
 110         spin_unlock(&authtab_lock);
 111 }
 112 EXPORT_SYMBOL_GPL(svc_auth_unregister);
 113
 114 /**************************************************
 115  * 'auth_domains' are stored in a hash table indexed by name.
 116  * When the last reference to an 'auth_domain' is dropped,
 117  * the object is unhashed and freed.
 118  * If auth_domain_lookup fails to find an entry, it will return
 119  * it's second argument 'new'.  If this is non-null, it will
 120  * have been atomically linked into the table.
 121  */
 122
 123 #define DN_HASHBITS     6
 124 #define DN_HASHMAX      (1<<DN_HASHBITS)
 125
 126 static struct hlist_head        auth_domain_table[DN_HASHMAX];
 127 static spinlock_t       auth_domain_lock =
 128         __SPIN_LOCK_UNLOCKED(auth_domain_lock);
 129
 130 void auth_domain_put(struct auth_domain *dom)
 131 {
 132         if (atomic_dec_and_lock(&dom->ref.refcount, &auth_domain_lock)) {
 133                 hlist_del(&dom->hash);
 134                 dom->flavour->domain_release(dom);
 135                 spin_unlock(&auth_domain_lock);
 136         }
 137 }
 138 EXPORT_SYMBOL_GPL(auth_domain_put);
 139
 140 struct auth_domain *
 141 auth_domain_lookup(char *name, struct auth_domain *new)
 142 {
 143         struct auth_domain *hp;
 144         struct hlist_head *head;
 145
 146         head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
 147
 148         spin_lock(&auth_domain_lock);
 149
 150         hlist_for_each_entry(hp, head, hash) {
 151                 if (strcmp(hp->name, name)==0) {
 152                         kref_get(&hp->ref);
 153                         spin_unlock(&auth_domain_lock);
 154                         return hp;
 155                 }
 156         }
 157         if (new)
 158                 hlist_add_head(&new->hash, head);
 159         spin_unlock(&auth_domain_lock);
 160         return new;
 161 }
 162 EXPORT_SYMBOL_GPL(auth_domain_lookup);
 163
 164 struct auth_domain *auth_domain_find(char *name)
 165 {
 166         return auth_domain_lookup(name, NULL);
 167 }
 168 EXPORT_SYMBOL_GPL(auth_domain_find);