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
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