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_authop = aops;
  58         return aops->accept(rqstp, authp);
  59 }
  60
  61 int svc_set_client(struct svc_rqst *rqstp)
  62 {
  63         return rqstp->rq_authop->set_client(rqstp);
  64 }
  65
  66 /* A request, which was authenticated, has now executed.
  67  * Time to finalise the credentials and verifier
  68  * and release and resources
  69  */
  70 int svc_authorise(struct svc_rqst *rqstp)
  71 {
  72         struct auth_ops *aops = rqstp->rq_authop;
  73         int rv = 0;
  74
  75         rqstp->rq_authop = NULL;
  76
  77         if (aops) {
  78                 rv = aops->release(rqstp);
  79                 module_put(aops->owner);
  80         }
  81         return rv;
  82 }
  83
  84 int
  85 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
  86 {
  87         int rv = -EINVAL;
  88         spin_lock(&authtab_lock);
  89         if (flavor < RPC_AUTH_MAXFLAVOR && authtab[flavor] == NULL) {
  90                 authtab[flavor] = aops;
  91                 rv = 0;
  92         }
  93         spin_unlock(&authtab_lock);
  94         return rv;
  95 }
  96
  97 void
  98 svc_auth_unregister(rpc_authflavor_t flavor)
  99 {
 100         spin_lock(&authtab_lock);
 101         if (flavor < RPC_AUTH_MAXFLAVOR)
 102                 authtab[flavor] = NULL;
 103         spin_unlock(&authtab_lock);
 104 }
 105 EXPORT_SYMBOL(svc_auth_unregister);
 106
 107 /**************************************************
 108  * 'auth_domains' are stored in a hash table indexed by name.
 109  * When the last reference to an 'auth_domain' is dropped,
 110  * the object is unhashed and freed.
 111  * If auth_domain_lookup fails to find an entry, it will return
 112  * it's second argument 'new'.  If this is non-null, it will
 113  * have been atomically linked into the table.
 114  */
 115
 116 #define DN_HASHBITS     6
 117 #define DN_HASHMAX      (1<<DN_HASHBITS)
 118 #define DN_HASHMASK     (DN_HASHMAX-1)
 119
 120 static struct hlist_head        auth_domain_table[DN_HASHMAX];
 121 static spinlock_t       auth_domain_lock =
 122         __SPIN_LOCK_UNLOCKED(auth_domain_lock);
 123
 124 void auth_domain_put(struct auth_domain *dom)
 125 {
 126         if (atomic_dec_and_lock(&dom->ref.refcount, &auth_domain_lock)) {
 127                 hlist_del(&dom->hash);
 128                 dom->flavour->domain_release(dom);
 129                 spin_unlock(&auth_domain_lock);
 130         }
 131 }
 132
 133 struct auth_domain *
 134 auth_domain_lookup(char *name, struct auth_domain *new)
 135 {
 136         struct auth_domain *hp;
 137         struct hlist_head *head;
 138         struct hlist_node *np;
 139
 140         head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
 141
 142         spin_lock(&auth_domain_lock);
 143
 144         hlist_for_each_entry(hp, np, head, hash) {
 145                 if (strcmp(hp->name, name)==0) {
 146                         kref_get(&hp->ref);
 147                         spin_unlock(&auth_domain_lock);
 148                         return hp;
 149                 }
 150         }
 151         if (new)
 152                 hlist_add_head(&new->hash, head);
 153         spin_unlock(&auth_domain_lock);
 154         return new;
 155 }
 156
 157 struct auth_domain *auth_domain_find(char *name)
 158 {
 159         return auth_domain_lookup(name, NULL);
 160 }