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 #include <trace/events/sunrpc.h> 23 24 #define RPCDBG_FACILITY RPCDBG_AUTH 25 26 27 /* 28 * Table of authenticators 29 */ 30 extern struct auth_ops svcauth_null; 31 extern struct auth_ops svcauth_unix; 32 33 static struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = { 34 [RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null, 35 [RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix, 36 }; 37 38 static struct auth_ops * 39 svc_get_auth_ops(rpc_authflavor_t flavor) 40 { 41 struct auth_ops *aops; 42 43 if (flavor >= RPC_AUTH_MAXFLAVOR) 44 return NULL; 45 rcu_read_lock(); 46 aops = rcu_dereference(authtab[flavor]); 47 if (aops != NULL && !try_module_get(aops->owner)) 48 aops = NULL; 49 rcu_read_unlock(); 50 return aops; 51 } 52 53 static void 54 svc_put_auth_ops(struct auth_ops *aops) 55 { 56 module_put(aops->owner); 57 } 58 59 int 60 svc_authenticate(struct svc_rqst *rqstp, __be32 *authp) 61 { 62 rpc_authflavor_t flavor; 63 struct auth_ops *aops; 64 65 *authp = rpc_auth_ok; 66 67 flavor = svc_getnl(&rqstp->rq_arg.head[0]); 68 69 dprintk("svc: svc_authenticate (%d)\n", flavor); 70 71 aops = svc_get_auth_ops(flavor); 72 if (aops == NULL) { 73 *authp = rpc_autherr_badcred; 74 return SVC_DENIED; 75 } 76 77 rqstp->rq_auth_slack = 0; 78 init_svc_cred(&rqstp->rq_cred); 79 80 rqstp->rq_authop = aops; 81 return aops->accept(rqstp, authp); 82 } 83 EXPORT_SYMBOL_GPL(svc_authenticate); 84 85 int svc_set_client(struct svc_rqst *rqstp) 86 { 87 rqstp->rq_client = NULL; 88 return rqstp->rq_authop->set_client(rqstp); 89 } 90 EXPORT_SYMBOL_GPL(svc_set_client); 91 92 /* A request, which was authenticated, has now executed. 93 * Time to finalise the credentials and verifier 94 * and release and resources 95 */ 96 int svc_authorise(struct svc_rqst *rqstp) 97 { 98 struct auth_ops *aops = rqstp->rq_authop; 99 int rv = 0; 100 101 rqstp->rq_authop = NULL; 102 103 if (aops) { 104 rv = aops->release(rqstp); 105 svc_put_auth_ops(aops); 106 } 107 return rv; 108 } 109 110 int 111 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops) 112 { 113 struct auth_ops *old; 114 int rv = -EINVAL; 115 116 if (flavor < RPC_AUTH_MAXFLAVOR) { 117 old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops); 118 if (old == NULL || old == aops) 119 rv = 0; 120 } 121 return rv; 122 } 123 EXPORT_SYMBOL_GPL(svc_auth_register); 124 125 void 126 svc_auth_unregister(rpc_authflavor_t flavor) 127 { 128 if (flavor < RPC_AUTH_MAXFLAVOR) 129 rcu_assign_pointer(authtab[flavor], NULL); 130 } 131 EXPORT_SYMBOL_GPL(svc_auth_unregister); 132 133 /************************************************** 134 * 'auth_domains' are stored in a hash table indexed by name. 135 * When the last reference to an 'auth_domain' is dropped, 136 * the object is unhashed and freed. 137 * If auth_domain_lookup fails to find an entry, it will return 138 * it's second argument 'new'. If this is non-null, it will 139 * have been atomically linked into the table. 140 */ 141 142 #define DN_HASHBITS 6 143 #define DN_HASHMAX (1<<DN_HASHBITS) 144 145 static struct hlist_head auth_domain_table[DN_HASHMAX]; 146 static DEFINE_SPINLOCK(auth_domain_lock); 147 148 static void auth_domain_release(struct kref *kref) 149 __releases(&auth_domain_lock) 150 { 151 struct auth_domain *dom = container_of(kref, struct auth_domain, ref); 152 153 hlist_del_rcu(&dom->hash); 154 dom->flavour->domain_release(dom); 155 spin_unlock(&auth_domain_lock); 156 } 157 158 void auth_domain_put(struct auth_domain *dom) 159 { 160 kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock); 161 } 162 EXPORT_SYMBOL_GPL(auth_domain_put); 163 164 struct auth_domain * 165 auth_domain_lookup(char *name, struct auth_domain *new) 166 { 167 struct auth_domain *hp; 168 struct hlist_head *head; 169 170 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 171 172 spin_lock(&auth_domain_lock); 173 174 hlist_for_each_entry(hp, head, hash) { 175 if (strcmp(hp->name, name)==0) { 176 kref_get(&hp->ref); 177 spin_unlock(&auth_domain_lock); 178 return hp; 179 } 180 } 181 if (new) 182 hlist_add_head_rcu(&new->hash, head); 183 spin_unlock(&auth_domain_lock); 184 return new; 185 } 186 EXPORT_SYMBOL_GPL(auth_domain_lookup); 187 188 struct auth_domain *auth_domain_find(char *name) 189 { 190 struct auth_domain *hp; 191 struct hlist_head *head; 192 193 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 194 195 rcu_read_lock(); 196 hlist_for_each_entry_rcu(hp, head, hash) { 197 if (strcmp(hp->name, name)==0) { 198 if (!kref_get_unless_zero(&hp->ref)) 199 hp = NULL; 200 rcu_read_unlock(); 201 return hp; 202 } 203 } 204 rcu_read_unlock(); 205 return NULL; 206 } 207 EXPORT_SYMBOL_GPL(auth_domain_find); 208