1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/net/sunrpc/svcauth.c 4 * 5 * The generic interface for RPC authentication on the server side. 6 * 7 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> 8 * 9 * CHANGES 10 * 19-Apr-2000 Chris Evans - Security fix 11 */ 12 13 #include <linux/types.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 struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = { 32 [RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null, 33 [RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix, 34 }; 35 36 static struct auth_ops * 37 svc_get_auth_ops(rpc_authflavor_t flavor) 38 { 39 struct auth_ops *aops; 40 41 if (flavor >= RPC_AUTH_MAXFLAVOR) 42 return NULL; 43 rcu_read_lock(); 44 aops = rcu_dereference(authtab[flavor]); 45 if (aops != NULL && !try_module_get(aops->owner)) 46 aops = NULL; 47 rcu_read_unlock(); 48 return aops; 49 } 50 51 static void 52 svc_put_auth_ops(struct auth_ops *aops) 53 { 54 module_put(aops->owner); 55 } 56 57 int 58 svc_authenticate(struct svc_rqst *rqstp, __be32 *authp) 59 { 60 rpc_authflavor_t flavor; 61 struct auth_ops *aops; 62 63 *authp = rpc_auth_ok; 64 65 flavor = svc_getnl(&rqstp->rq_arg.head[0]); 66 67 dprintk("svc: svc_authenticate (%d)\n", flavor); 68 69 aops = svc_get_auth_ops(flavor); 70 if (aops == NULL) { 71 *authp = rpc_autherr_badcred; 72 return SVC_DENIED; 73 } 74 75 rqstp->rq_auth_slack = 0; 76 init_svc_cred(&rqstp->rq_cred); 77 78 rqstp->rq_authop = aops; 79 return aops->accept(rqstp, authp); 80 } 81 EXPORT_SYMBOL_GPL(svc_authenticate); 82 83 int svc_set_client(struct svc_rqst *rqstp) 84 { 85 rqstp->rq_client = NULL; 86 return rqstp->rq_authop->set_client(rqstp); 87 } 88 EXPORT_SYMBOL_GPL(svc_set_client); 89 90 /* A request, which was authenticated, has now executed. 91 * Time to finalise the credentials and verifier 92 * and release and resources 93 */ 94 int svc_authorise(struct svc_rqst *rqstp) 95 { 96 struct auth_ops *aops = rqstp->rq_authop; 97 int rv = 0; 98 99 rqstp->rq_authop = NULL; 100 101 if (aops) { 102 rv = aops->release(rqstp); 103 svc_put_auth_ops(aops); 104 } 105 return rv; 106 } 107 108 int 109 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops) 110 { 111 struct auth_ops *old; 112 int rv = -EINVAL; 113 114 if (flavor < RPC_AUTH_MAXFLAVOR) { 115 old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops); 116 if (old == NULL || old == aops) 117 rv = 0; 118 } 119 return rv; 120 } 121 EXPORT_SYMBOL_GPL(svc_auth_register); 122 123 void 124 svc_auth_unregister(rpc_authflavor_t flavor) 125 { 126 if (flavor < RPC_AUTH_MAXFLAVOR) 127 rcu_assign_pointer(authtab[flavor], NULL); 128 } 129 EXPORT_SYMBOL_GPL(svc_auth_unregister); 130 131 /************************************************** 132 * 'auth_domains' are stored in a hash table indexed by name. 133 * When the last reference to an 'auth_domain' is dropped, 134 * the object is unhashed and freed. 135 * If auth_domain_lookup fails to find an entry, it will return 136 * it's second argument 'new'. If this is non-null, it will 137 * have been atomically linked into the table. 138 */ 139 140 #define DN_HASHBITS 6 141 #define DN_HASHMAX (1<<DN_HASHBITS) 142 143 static struct hlist_head auth_domain_table[DN_HASHMAX]; 144 static DEFINE_SPINLOCK(auth_domain_lock); 145 146 static void auth_domain_release(struct kref *kref) 147 __releases(&auth_domain_lock) 148 { 149 struct auth_domain *dom = container_of(kref, struct auth_domain, ref); 150 151 hlist_del_rcu(&dom->hash); 152 dom->flavour->domain_release(dom); 153 spin_unlock(&auth_domain_lock); 154 } 155 156 void auth_domain_put(struct auth_domain *dom) 157 { 158 kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock); 159 } 160 EXPORT_SYMBOL_GPL(auth_domain_put); 161 162 struct auth_domain * 163 auth_domain_lookup(char *name, struct auth_domain *new) 164 { 165 struct auth_domain *hp; 166 struct hlist_head *head; 167 168 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 169 170 spin_lock(&auth_domain_lock); 171 172 hlist_for_each_entry(hp, head, hash) { 173 if (strcmp(hp->name, name)==0) { 174 kref_get(&hp->ref); 175 spin_unlock(&auth_domain_lock); 176 return hp; 177 } 178 } 179 if (new) 180 hlist_add_head_rcu(&new->hash, head); 181 spin_unlock(&auth_domain_lock); 182 return new; 183 } 184 EXPORT_SYMBOL_GPL(auth_domain_lookup); 185 186 struct auth_domain *auth_domain_find(char *name) 187 { 188 struct auth_domain *hp; 189 struct hlist_head *head; 190 191 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 192 193 rcu_read_lock(); 194 hlist_for_each_entry_rcu(hp, head, hash) { 195 if (strcmp(hp->name, name)==0) { 196 if (!kref_get_unless_zero(&hp->ref)) 197 hp = NULL; 198 rcu_read_unlock(); 199 return hp; 200 } 201 } 202 rcu_read_unlock(); 203 return NULL; 204 } 205 EXPORT_SYMBOL_GPL(auth_domain_find); 206