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 #include "sunrpc.h" 25 26 #define RPCDBG_FACILITY RPCDBG_AUTH 27 28 29 /* 30 * Table of authenticators 31 */ 32 extern struct auth_ops svcauth_null; 33 extern struct auth_ops svcauth_unix; 34 extern struct auth_ops svcauth_tls; 35 36 static struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = { 37 [RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null, 38 [RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix, 39 [RPC_AUTH_TLS] = (struct auth_ops __force __rcu *)&svcauth_tls, 40 }; 41 42 static struct auth_ops * 43 svc_get_auth_ops(rpc_authflavor_t flavor) 44 { 45 struct auth_ops *aops; 46 47 if (flavor >= RPC_AUTH_MAXFLAVOR) 48 return NULL; 49 rcu_read_lock(); 50 aops = rcu_dereference(authtab[flavor]); 51 if (aops != NULL && !try_module_get(aops->owner)) 52 aops = NULL; 53 rcu_read_unlock(); 54 return aops; 55 } 56 57 static void 58 svc_put_auth_ops(struct auth_ops *aops) 59 { 60 module_put(aops->owner); 61 } 62 63 /** 64 * svc_authenticate - Initialize an outgoing credential 65 * @rqstp: RPC execution context 66 * 67 * Return values: 68 * %SVC_OK: XDR encoding of the result can begin 69 * %SVC_DENIED: Credential or verifier is not valid 70 * %SVC_GARBAGE: Failed to decode credential or verifier 71 * %SVC_COMPLETE: GSS context lifetime event; no further action 72 * %SVC_DROP: Drop this request; no further action 73 * %SVC_CLOSE: Like drop, but also close transport connection 74 */ 75 enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp) 76 { 77 struct auth_ops *aops; 78 u32 flavor; 79 80 rqstp->rq_auth_stat = rpc_auth_ok; 81 82 /* 83 * Decode the Call credential's flavor field. The credential's 84 * body field is decoded in the chosen ->accept method below. 85 */ 86 if (xdr_stream_decode_u32(&rqstp->rq_arg_stream, &flavor) < 0) 87 return SVC_GARBAGE; 88 89 aops = svc_get_auth_ops(flavor); 90 if (aops == NULL) { 91 rqstp->rq_auth_stat = rpc_autherr_badcred; 92 return SVC_DENIED; 93 } 94 95 rqstp->rq_auth_slack = 0; 96 init_svc_cred(&rqstp->rq_cred); 97 98 rqstp->rq_authop = aops; 99 return aops->accept(rqstp); 100 } 101 EXPORT_SYMBOL_GPL(svc_authenticate); 102 103 /** 104 * svc_set_client - Assign an appropriate 'auth_domain' as the client 105 * @rqstp: RPC execution context 106 * 107 * Return values: 108 * %SVC_OK: Client was found and assigned 109 * %SVC_DENY: Client was explicitly denied 110 * %SVC_DROP: Ignore this request 111 * %SVC_CLOSE: Ignore this request and close the connection 112 */ 113 enum svc_auth_status svc_set_client(struct svc_rqst *rqstp) 114 { 115 rqstp->rq_client = NULL; 116 return rqstp->rq_authop->set_client(rqstp); 117 } 118 EXPORT_SYMBOL_GPL(svc_set_client); 119 120 /** 121 * svc_authorise - Finalize credentials/verifier and release resources 122 * @rqstp: RPC execution context 123 * 124 * Returns zero on success, or a negative errno. 125 */ 126 int svc_authorise(struct svc_rqst *rqstp) 127 { 128 struct auth_ops *aops = rqstp->rq_authop; 129 int rv = 0; 130 131 rqstp->rq_authop = NULL; 132 133 if (aops) { 134 rv = aops->release(rqstp); 135 svc_put_auth_ops(aops); 136 } 137 return rv; 138 } 139 140 int 141 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops) 142 { 143 struct auth_ops *old; 144 int rv = -EINVAL; 145 146 if (flavor < RPC_AUTH_MAXFLAVOR) { 147 old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops); 148 if (old == NULL || old == aops) 149 rv = 0; 150 } 151 return rv; 152 } 153 EXPORT_SYMBOL_GPL(svc_auth_register); 154 155 void 156 svc_auth_unregister(rpc_authflavor_t flavor) 157 { 158 if (flavor < RPC_AUTH_MAXFLAVOR) 159 rcu_assign_pointer(authtab[flavor], NULL); 160 } 161 EXPORT_SYMBOL_GPL(svc_auth_unregister); 162 163 /** 164 * svc_auth_flavor - return RPC transaction's RPC_AUTH flavor 165 * @rqstp: RPC transaction context 166 * 167 * Returns an RPC flavor or GSS pseudoflavor. 168 */ 169 rpc_authflavor_t svc_auth_flavor(struct svc_rqst *rqstp) 170 { 171 struct auth_ops *aops = rqstp->rq_authop; 172 173 if (!aops->pseudoflavor) 174 return aops->flavour; 175 return aops->pseudoflavor(rqstp); 176 } 177 EXPORT_SYMBOL_GPL(svc_auth_flavor); 178 179 /************************************************** 180 * 'auth_domains' are stored in a hash table indexed by name. 181 * When the last reference to an 'auth_domain' is dropped, 182 * the object is unhashed and freed. 183 * If auth_domain_lookup fails to find an entry, it will return 184 * it's second argument 'new'. If this is non-null, it will 185 * have been atomically linked into the table. 186 */ 187 188 #define DN_HASHBITS 6 189 #define DN_HASHMAX (1<<DN_HASHBITS) 190 191 static struct hlist_head auth_domain_table[DN_HASHMAX]; 192 static DEFINE_SPINLOCK(auth_domain_lock); 193 194 static void auth_domain_release(struct kref *kref) 195 __releases(&auth_domain_lock) 196 { 197 struct auth_domain *dom = container_of(kref, struct auth_domain, ref); 198 199 hlist_del_rcu(&dom->hash); 200 dom->flavour->domain_release(dom); 201 spin_unlock(&auth_domain_lock); 202 } 203 204 void auth_domain_put(struct auth_domain *dom) 205 { 206 kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock); 207 } 208 EXPORT_SYMBOL_GPL(auth_domain_put); 209 210 struct auth_domain * 211 auth_domain_lookup(char *name, struct auth_domain *new) 212 { 213 struct auth_domain *hp; 214 struct hlist_head *head; 215 216 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 217 218 spin_lock(&auth_domain_lock); 219 220 hlist_for_each_entry(hp, head, hash) { 221 if (strcmp(hp->name, name)==0) { 222 kref_get(&hp->ref); 223 spin_unlock(&auth_domain_lock); 224 return hp; 225 } 226 } 227 if (new) 228 hlist_add_head_rcu(&new->hash, head); 229 spin_unlock(&auth_domain_lock); 230 return new; 231 } 232 EXPORT_SYMBOL_GPL(auth_domain_lookup); 233 234 struct auth_domain *auth_domain_find(char *name) 235 { 236 struct auth_domain *hp; 237 struct hlist_head *head; 238 239 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 240 241 rcu_read_lock(); 242 hlist_for_each_entry_rcu(hp, head, hash) { 243 if (strcmp(hp->name, name)==0) { 244 if (!kref_get_unless_zero(&hp->ref)) 245 hp = NULL; 246 rcu_read_unlock(); 247 return hp; 248 } 249 } 250 rcu_read_unlock(); 251 return NULL; 252 } 253 EXPORT_SYMBOL_GPL(auth_domain_find); 254 255 /** 256 * auth_domain_cleanup - check that the auth_domain table is empty 257 * 258 * On module unload the auth_domain_table must be empty. To make it 259 * easier to catch bugs which don't clean up domains properly, we 260 * warn if anything remains in the table at cleanup time. 261 * 262 * Note that we cannot proactively remove the domains at this stage. 263 * The ->release() function might be in a module that has already been 264 * unloaded. 265 */ 266 267 void auth_domain_cleanup(void) 268 { 269 int h; 270 struct auth_domain *hp; 271 272 for (h = 0; h < DN_HASHMAX; h++) 273 hlist_for_each_entry(hp, &auth_domain_table[h], hash) 274 pr_warn("svc: domain %s still present at module unload.\n", 275 hp->name); 276 } 277