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 #include <linux/user_namespace.h> 22 23 #include <trace/events/sunrpc.h> 24 25 #include "sunrpc.h" 26 27 #define RPCDBG_FACILITY RPCDBG_AUTH 28 29 30 /* 31 * Table of authenticators 32 */ 33 extern struct auth_ops svcauth_null; 34 extern struct auth_ops svcauth_unix; 35 extern struct auth_ops svcauth_tls; 36 37 static struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = { 38 [RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null, 39 [RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix, 40 [RPC_AUTH_TLS] = (struct auth_ops __force __rcu *)&svcauth_tls, 41 }; 42 43 static struct auth_ops * 44 svc_get_auth_ops(rpc_authflavor_t flavor) 45 { 46 struct auth_ops *aops; 47 48 if (flavor >= RPC_AUTH_MAXFLAVOR) 49 return NULL; 50 rcu_read_lock(); 51 aops = rcu_dereference(authtab[flavor]); 52 if (aops != NULL && !try_module_get(aops->owner)) 53 aops = NULL; 54 rcu_read_unlock(); 55 return aops; 56 } 57 58 static void 59 svc_put_auth_ops(struct auth_ops *aops) 60 { 61 module_put(aops->owner); 62 } 63 64 /** 65 * svc_authenticate - Initialize an outgoing credential 66 * @rqstp: RPC execution context 67 * 68 * Return values: 69 * %SVC_OK: XDR encoding of the result can begin 70 * %SVC_DENIED: Credential or verifier is not valid 71 * %SVC_GARBAGE: Failed to decode credential or verifier 72 * %SVC_COMPLETE: GSS context lifetime event; no further action 73 * %SVC_DROP: Drop this request; no further action 74 * %SVC_CLOSE: Like drop, but also close transport connection 75 */ 76 enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp) 77 { 78 struct auth_ops *aops; 79 u32 flavor; 80 81 rqstp->rq_auth_stat = rpc_auth_ok; 82 83 /* 84 * Decode the Call credential's flavor field. The credential's 85 * body field is decoded in the chosen ->accept method below. 86 */ 87 if (xdr_stream_decode_u32(&rqstp->rq_arg_stream, &flavor) < 0) 88 return SVC_GARBAGE; 89 90 aops = svc_get_auth_ops(flavor); 91 if (aops == NULL) { 92 rqstp->rq_auth_stat = rpc_autherr_badcred; 93 return SVC_DENIED; 94 } 95 96 rqstp->rq_auth_slack = 0; 97 init_svc_cred(&rqstp->rq_cred); 98 99 rqstp->rq_authop = aops; 100 return aops->accept(rqstp); 101 } 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 * svcauth_map_clnt_to_svc_cred_local - maps a generic cred 181 * to a svc_cred suitable for use in nfsd. 182 * @clnt: rpc_clnt associated with nfs client 183 * @cred: generic cred associated with nfs client 184 * @svc: returned svc_cred that is suitable for use in nfsd 185 */ 186 void svcauth_map_clnt_to_svc_cred_local(struct rpc_clnt *clnt, 187 const struct cred *cred, 188 struct svc_cred *svc) 189 { 190 struct user_namespace *userns = clnt->cl_cred ? 191 clnt->cl_cred->user_ns : &init_user_ns; 192 193 memset(svc, 0, sizeof(struct svc_cred)); 194 195 svc->cr_uid = KUIDT_INIT(from_kuid_munged(userns, cred->fsuid)); 196 svc->cr_gid = KGIDT_INIT(from_kgid_munged(userns, cred->fsgid)); 197 svc->cr_flavor = clnt->cl_auth->au_flavor; 198 if (cred->group_info) 199 svc->cr_group_info = get_group_info(cred->group_info); 200 /* These aren't relevant for local (network is bypassed) */ 201 svc->cr_principal = NULL; 202 svc->cr_gss_mech = NULL; 203 } 204 EXPORT_SYMBOL_GPL(svcauth_map_clnt_to_svc_cred_local); 205 206 /************************************************** 207 * 'auth_domains' are stored in a hash table indexed by name. 208 * When the last reference to an 'auth_domain' is dropped, 209 * the object is unhashed and freed. 210 * If auth_domain_lookup fails to find an entry, it will return 211 * it's second argument 'new'. If this is non-null, it will 212 * have been atomically linked into the table. 213 */ 214 215 #define DN_HASHBITS 6 216 #define DN_HASHMAX (1<<DN_HASHBITS) 217 218 static struct hlist_head auth_domain_table[DN_HASHMAX]; 219 static DEFINE_SPINLOCK(auth_domain_lock); 220 221 static void auth_domain_release(struct kref *kref) 222 __releases(&auth_domain_lock) 223 { 224 struct auth_domain *dom = container_of(kref, struct auth_domain, ref); 225 226 hlist_del_rcu(&dom->hash); 227 dom->flavour->domain_release(dom); 228 spin_unlock(&auth_domain_lock); 229 } 230 231 void auth_domain_put(struct auth_domain *dom) 232 { 233 kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock); 234 } 235 EXPORT_SYMBOL_GPL(auth_domain_put); 236 237 struct auth_domain * 238 auth_domain_lookup(char *name, struct auth_domain *new) 239 { 240 struct auth_domain *hp; 241 struct hlist_head *head; 242 243 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 244 245 spin_lock(&auth_domain_lock); 246 247 hlist_for_each_entry(hp, head, hash) { 248 if (strcmp(hp->name, name)==0) { 249 kref_get(&hp->ref); 250 spin_unlock(&auth_domain_lock); 251 return hp; 252 } 253 } 254 if (new) 255 hlist_add_head_rcu(&new->hash, head); 256 spin_unlock(&auth_domain_lock); 257 return new; 258 } 259 EXPORT_SYMBOL_GPL(auth_domain_lookup); 260 261 struct auth_domain *auth_domain_find(char *name) 262 { 263 struct auth_domain *hp; 264 struct hlist_head *head; 265 266 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 267 268 rcu_read_lock(); 269 hlist_for_each_entry_rcu(hp, head, hash) { 270 if (strcmp(hp->name, name)==0) { 271 if (!kref_get_unless_zero(&hp->ref)) 272 hp = NULL; 273 rcu_read_unlock(); 274 return hp; 275 } 276 } 277 rcu_read_unlock(); 278 return NULL; 279 } 280 EXPORT_SYMBOL_GPL(auth_domain_find); 281 282 /** 283 * auth_domain_cleanup - check that the auth_domain table is empty 284 * 285 * On module unload the auth_domain_table must be empty. To make it 286 * easier to catch bugs which don't clean up domains properly, we 287 * warn if anything remains in the table at cleanup time. 288 * 289 * Note that we cannot proactively remove the domains at this stage. 290 * The ->release() function might be in a module that has already been 291 * unloaded. 292 */ 293 294 void auth_domain_cleanup(void) 295 { 296 int h; 297 struct auth_domain *hp; 298 299 for (h = 0; h < DN_HASHMAX; h++) 300 hlist_for_each_entry(hp, &auth_domain_table[h], hash) 301 pr_warn("svc: domain %s still present at module unload.\n", 302 hp->name); 303 } 304