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