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 */
33extern struct auth_ops svcauth_null;
34extern struct auth_ops svcauth_unix;
35extern struct auth_ops svcauth_tls;
36
37static 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
43static struct auth_ops *
44svc_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(module: aops->owner))
53 aops = NULL;
54 rcu_read_unlock();
55 return aops;
56}
57
58static void
59svc_put_auth_ops(struct auth_ops *aops)
60{
61 module_put(module: 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 */
76enum 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(xdr: &rqstp->rq_arg_stream, ptr: &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(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 */
113enum 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}
118EXPORT_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 */
126int 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
140int
141svc_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}
153EXPORT_SYMBOL_GPL(svc_auth_register);
154
155void
156svc_auth_unregister(rpc_authflavor_t flavor)
157{
158 if (flavor < RPC_AUTH_MAXFLAVOR)
159 rcu_assign_pointer(authtab[flavor], NULL);
160}
161EXPORT_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 */
169rpc_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}
177EXPORT_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 */
186void 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(s: svc, c: 0, n: 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(gi: 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}
204EXPORT_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
218static struct hlist_head auth_domain_table[DN_HASHMAX];
219static DEFINE_SPINLOCK(auth_domain_lock);
220
221static 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(n: &dom->hash);
227 dom->flavour->domain_release(dom);
228 spin_unlock(lock: &auth_domain_lock);
229}
230
231void auth_domain_put(struct auth_domain *dom)
232{
233 kref_put_lock(kref: &dom->ref, release: auth_domain_release, lock: &auth_domain_lock);
234}
235EXPORT_SYMBOL_GPL(auth_domain_put);
236
237struct auth_domain *
238auth_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(lock: &auth_domain_lock);
246
247 hlist_for_each_entry(hp, head, hash) {
248 if (strcmp(hp->name, name)==0) {
249 kref_get(kref: &hp->ref);
250 spin_unlock(lock: &auth_domain_lock);
251 return hp;
252 }
253 }
254 if (new)
255 hlist_add_head_rcu(n: &new->hash, h: head);
256 spin_unlock(lock: &auth_domain_lock);
257 return new;
258}
259EXPORT_SYMBOL_GPL(auth_domain_lookup);
260
261struct 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(kref: &hp->ref))
272 hp = NULL;
273 rcu_read_unlock();
274 return hp;
275 }
276 }
277 rcu_read_unlock();
278 return NULL;
279}
280EXPORT_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
294void 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