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 struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = { 31 [RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null, 32 [RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix, 33 }; 34 35 static struct auth_ops * 36 svc_get_auth_ops(rpc_authflavor_t flavor) 37 { 38 struct auth_ops *aops; 39 40 if (flavor >= RPC_AUTH_MAXFLAVOR) 41 return NULL; 42 rcu_read_lock(); 43 aops = rcu_dereference(authtab[flavor]); 44 if (aops != NULL && !try_module_get(aops->owner)) 45 aops = NULL; 46 rcu_read_unlock(); 47 return aops; 48 } 49 50 static void 51 svc_put_auth_ops(struct auth_ops *aops) 52 { 53 module_put(aops->owner); 54 } 55 56 int 57 svc_authenticate(struct svc_rqst *rqstp, __be32 *authp) 58 { 59 rpc_authflavor_t flavor; 60 struct auth_ops *aops; 61 62 *authp = rpc_auth_ok; 63 64 flavor = svc_getnl(&rqstp->rq_arg.head[0]); 65 66 dprintk("svc: svc_authenticate (%d)\n", flavor); 67 68 aops = svc_get_auth_ops(flavor); 69 if (aops == NULL) { 70 *authp = rpc_autherr_badcred; 71 return SVC_DENIED; 72 } 73 74 rqstp->rq_auth_slack = 0; 75 init_svc_cred(&rqstp->rq_cred); 76 77 rqstp->rq_authop = aops; 78 return aops->accept(rqstp, authp); 79 } 80 EXPORT_SYMBOL_GPL(svc_authenticate); 81 82 int svc_set_client(struct svc_rqst *rqstp) 83 { 84 rqstp->rq_client = NULL; 85 return rqstp->rq_authop->set_client(rqstp); 86 } 87 EXPORT_SYMBOL_GPL(svc_set_client); 88 89 /* A request, which was authenticated, has now executed. 90 * Time to finalise the credentials and verifier 91 * and release and resources 92 */ 93 int svc_authorise(struct svc_rqst *rqstp) 94 { 95 struct auth_ops *aops = rqstp->rq_authop; 96 int rv = 0; 97 98 rqstp->rq_authop = NULL; 99 100 if (aops) { 101 rv = aops->release(rqstp); 102 svc_put_auth_ops(aops); 103 } 104 return rv; 105 } 106 107 int 108 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops) 109 { 110 struct auth_ops *old; 111 int rv = -EINVAL; 112 113 if (flavor < RPC_AUTH_MAXFLAVOR) { 114 old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops); 115 if (old == NULL || old == aops) 116 rv = 0; 117 } 118 return rv; 119 } 120 EXPORT_SYMBOL_GPL(svc_auth_register); 121 122 void 123 svc_auth_unregister(rpc_authflavor_t flavor) 124 { 125 if (flavor < RPC_AUTH_MAXFLAVOR) 126 rcu_assign_pointer(authtab[flavor], NULL); 127 } 128 EXPORT_SYMBOL_GPL(svc_auth_unregister); 129 130 /************************************************** 131 * 'auth_domains' are stored in a hash table indexed by name. 132 * When the last reference to an 'auth_domain' is dropped, 133 * the object is unhashed and freed. 134 * If auth_domain_lookup fails to find an entry, it will return 135 * it's second argument 'new'. If this is non-null, it will 136 * have been atomically linked into the table. 137 */ 138 139 #define DN_HASHBITS 6 140 #define DN_HASHMAX (1<<DN_HASHBITS) 141 142 static struct hlist_head auth_domain_table[DN_HASHMAX]; 143 static DEFINE_SPINLOCK(auth_domain_lock); 144 145 static void auth_domain_release(struct kref *kref) 146 { 147 struct auth_domain *dom = container_of(kref, struct auth_domain, ref); 148 149 hlist_del(&dom->hash); 150 dom->flavour->domain_release(dom); 151 spin_unlock(&auth_domain_lock); 152 } 153 154 void auth_domain_put(struct auth_domain *dom) 155 { 156 kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock); 157 } 158 EXPORT_SYMBOL_GPL(auth_domain_put); 159 160 struct auth_domain * 161 auth_domain_lookup(char *name, struct auth_domain *new) 162 { 163 struct auth_domain *hp; 164 struct hlist_head *head; 165 166 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 167 168 spin_lock(&auth_domain_lock); 169 170 hlist_for_each_entry(hp, head, hash) { 171 if (strcmp(hp->name, name)==0) { 172 kref_get(&hp->ref); 173 spin_unlock(&auth_domain_lock); 174 return hp; 175 } 176 } 177 if (new) 178 hlist_add_head(&new->hash, head); 179 spin_unlock(&auth_domain_lock); 180 return new; 181 } 182 EXPORT_SYMBOL_GPL(auth_domain_lookup); 183 184 struct auth_domain *auth_domain_find(char *name) 185 { 186 return auth_domain_lookup(name, NULL); 187 } 188 EXPORT_SYMBOL_GPL(auth_domain_find); 189