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 int 64 svc_authenticate(struct svc_rqst *rqstp) 65 { 66 struct auth_ops *aops; 67 u32 flavor; 68 69 rqstp->rq_auth_stat = rpc_auth_ok; 70 71 /* 72 * Decode the Call credential's flavor field. The credential's 73 * body field is decoded in the chosen ->accept method below. 74 */ 75 if (xdr_stream_decode_u32(&rqstp->rq_arg_stream, &flavor) < 0) 76 return SVC_GARBAGE; 77 78 aops = svc_get_auth_ops(flavor); 79 if (aops == NULL) { 80 rqstp->rq_auth_stat = rpc_autherr_badcred; 81 return SVC_DENIED; 82 } 83 84 rqstp->rq_auth_slack = 0; 85 init_svc_cred(&rqstp->rq_cred); 86 87 rqstp->rq_authop = aops; 88 return aops->accept(rqstp); 89 } 90 EXPORT_SYMBOL_GPL(svc_authenticate); 91 92 int svc_set_client(struct svc_rqst *rqstp) 93 { 94 rqstp->rq_client = NULL; 95 return rqstp->rq_authop->set_client(rqstp); 96 } 97 EXPORT_SYMBOL_GPL(svc_set_client); 98 99 /* A request, which was authenticated, has now executed. 100 * Time to finalise the credentials and verifier 101 * and release and resources 102 */ 103 int svc_authorise(struct svc_rqst *rqstp) 104 { 105 struct auth_ops *aops = rqstp->rq_authop; 106 int rv = 0; 107 108 rqstp->rq_authop = NULL; 109 110 if (aops) { 111 rv = aops->release(rqstp); 112 svc_put_auth_ops(aops); 113 } 114 return rv; 115 } 116 117 int 118 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops) 119 { 120 struct auth_ops *old; 121 int rv = -EINVAL; 122 123 if (flavor < RPC_AUTH_MAXFLAVOR) { 124 old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops); 125 if (old == NULL || old == aops) 126 rv = 0; 127 } 128 return rv; 129 } 130 EXPORT_SYMBOL_GPL(svc_auth_register); 131 132 void 133 svc_auth_unregister(rpc_authflavor_t flavor) 134 { 135 if (flavor < RPC_AUTH_MAXFLAVOR) 136 rcu_assign_pointer(authtab[flavor], NULL); 137 } 138 EXPORT_SYMBOL_GPL(svc_auth_unregister); 139 140 /************************************************** 141 * 'auth_domains' are stored in a hash table indexed by name. 142 * When the last reference to an 'auth_domain' is dropped, 143 * the object is unhashed and freed. 144 * If auth_domain_lookup fails to find an entry, it will return 145 * it's second argument 'new'. If this is non-null, it will 146 * have been atomically linked into the table. 147 */ 148 149 #define DN_HASHBITS 6 150 #define DN_HASHMAX (1<<DN_HASHBITS) 151 152 static struct hlist_head auth_domain_table[DN_HASHMAX]; 153 static DEFINE_SPINLOCK(auth_domain_lock); 154 155 static void auth_domain_release(struct kref *kref) 156 __releases(&auth_domain_lock) 157 { 158 struct auth_domain *dom = container_of(kref, struct auth_domain, ref); 159 160 hlist_del_rcu(&dom->hash); 161 dom->flavour->domain_release(dom); 162 spin_unlock(&auth_domain_lock); 163 } 164 165 void auth_domain_put(struct auth_domain *dom) 166 { 167 kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock); 168 } 169 EXPORT_SYMBOL_GPL(auth_domain_put); 170 171 struct auth_domain * 172 auth_domain_lookup(char *name, struct auth_domain *new) 173 { 174 struct auth_domain *hp; 175 struct hlist_head *head; 176 177 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 178 179 spin_lock(&auth_domain_lock); 180 181 hlist_for_each_entry(hp, head, hash) { 182 if (strcmp(hp->name, name)==0) { 183 kref_get(&hp->ref); 184 spin_unlock(&auth_domain_lock); 185 return hp; 186 } 187 } 188 if (new) 189 hlist_add_head_rcu(&new->hash, head); 190 spin_unlock(&auth_domain_lock); 191 return new; 192 } 193 EXPORT_SYMBOL_GPL(auth_domain_lookup); 194 195 struct auth_domain *auth_domain_find(char *name) 196 { 197 struct auth_domain *hp; 198 struct hlist_head *head; 199 200 head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; 201 202 rcu_read_lock(); 203 hlist_for_each_entry_rcu(hp, head, hash) { 204 if (strcmp(hp->name, name)==0) { 205 if (!kref_get_unless_zero(&hp->ref)) 206 hp = NULL; 207 rcu_read_unlock(); 208 return hp; 209 } 210 } 211 rcu_read_unlock(); 212 return NULL; 213 } 214 EXPORT_SYMBOL_GPL(auth_domain_find); 215 216 /** 217 * auth_domain_cleanup - check that the auth_domain table is empty 218 * 219 * On module unload the auth_domain_table must be empty. To make it 220 * easier to catch bugs which don't clean up domains properly, we 221 * warn if anything remains in the table at cleanup time. 222 * 223 * Note that we cannot proactively remove the domains at this stage. 224 * The ->release() function might be in a module that has already been 225 * unloaded. 226 */ 227 228 void auth_domain_cleanup(void) 229 { 230 int h; 231 struct auth_domain *hp; 232 233 for (h = 0; h < DN_HASHMAX; h++) 234 hlist_for_each_entry(hp, &auth_domain_table[h], hash) 235 pr_warn("svc: domain %s still present at module unload.\n", 236 hp->name); 237 } 238