/net/sunrpc/svcauth.c

  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#define RPCDBG_FACILITY	RPCDBG_AUTH
 25
 26
 27/*
 28 * Table of authenticators
 29 */
 30extern struct auth_ops svcauth_null;
 31extern struct auth_ops svcauth_unix;
 32
 33static struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = {
 34	[RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null,
 35	[RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix,
 36};
 37
 38static struct auth_ops *
 39svc_get_auth_ops(rpc_authflavor_t flavor)
 40{
 41	struct auth_ops		*aops;
 42
 43	if (flavor >= RPC_AUTH_MAXFLAVOR)
 44		return NULL;
 45	rcu_read_lock();
 46	aops = rcu_dereference(authtab[flavor]);
 47	if (aops != NULL && !try_module_get(aops->owner))
 48		aops = NULL;
 49	rcu_read_unlock();
 50	return aops;
 51}
 52
 53static void
 54svc_put_auth_ops(struct auth_ops *aops)
 55{
 56	module_put(aops->owner);
 57}
 58
 59int
 60svc_authenticate(struct svc_rqst *rqstp, __be32 *authp)
 61{
 62	rpc_authflavor_t	flavor;
 63	struct auth_ops		*aops;
 64
 65	*authp = rpc_auth_ok;
 66
 67	flavor = svc_getnl(&rqstp->rq_arg.head[0]);
 68
 69	dprintk("svc: svc_authenticate (%d)\n", flavor);
 70
 71	aops = svc_get_auth_ops(flavor);
 72	if (aops == NULL) {
 73		*authp = rpc_autherr_badcred;
 74		return SVC_DENIED;
 75	}
 76
 77	rqstp->rq_auth_slack = 0;
 78	init_svc_cred(&rqstp->rq_cred);
 79
 80	rqstp->rq_authop = aops;
 81	return aops->accept(rqstp, authp);
 82}
 83EXPORT_SYMBOL_GPL(svc_authenticate);
 84
 85int svc_set_client(struct svc_rqst *rqstp)
 86{
 87	rqstp->rq_client = NULL;
 88	return rqstp->rq_authop->set_client(rqstp);
 89}
 90EXPORT_SYMBOL_GPL(svc_set_client);
 91
 92/* A request, which was authenticated, has now executed.
 93 * Time to finalise the credentials and verifier
 94 * and release and resources
 95 */
 96int svc_authorise(struct svc_rqst *rqstp)
 97{
 98	struct auth_ops *aops = rqstp->rq_authop;
 99	int rv = 0;
100
101	rqstp->rq_authop = NULL;
102
103	if (aops) {
104		rv = aops->release(rqstp);
105		svc_put_auth_ops(aops);
106	}
107	return rv;
108}
109
110int
111svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
112{
113	struct auth_ops *old;
114	int rv = -EINVAL;
115
116	if (flavor < RPC_AUTH_MAXFLAVOR) {
117		old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops);
118		if (old == NULL || old == aops)
119			rv = 0;
120	}
121	return rv;
122}
123EXPORT_SYMBOL_GPL(svc_auth_register);
124
125void
126svc_auth_unregister(rpc_authflavor_t flavor)
127{
128	if (flavor < RPC_AUTH_MAXFLAVOR)
129		rcu_assign_pointer(authtab[flavor], NULL);
130}
131EXPORT_SYMBOL_GPL(svc_auth_unregister);
132
133/**************************************************
134 * 'auth_domains' are stored in a hash table indexed by name.
135 * When the last reference to an 'auth_domain' is dropped,
136 * the object is unhashed and freed.
137 * If auth_domain_lookup fails to find an entry, it will return
138 * it's second argument 'new'.  If this is non-null, it will
139 * have been atomically linked into the table.
140 */
141
142#define	DN_HASHBITS	6
143#define	DN_HASHMAX	(1<<DN_HASHBITS)
144
145static struct hlist_head	auth_domain_table[DN_HASHMAX];
146static DEFINE_SPINLOCK(auth_domain_lock);
147
148static void auth_domain_release(struct kref *kref)
149	__releases(&auth_domain_lock)
150{
151	struct auth_domain *dom = container_of(kref, struct auth_domain, ref);
152
153	hlist_del_rcu(&dom->hash);
154	dom->flavour->domain_release(dom);
155	spin_unlock(&auth_domain_lock);
156}
157
158void auth_domain_put(struct auth_domain *dom)
159{
160	kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock);
161}
162EXPORT_SYMBOL_GPL(auth_domain_put);
163
164struct auth_domain *
165auth_domain_lookup(char *name, struct auth_domain *new)
166{
167	struct auth_domain *hp;
168	struct hlist_head *head;
169
170	head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
171
172	spin_lock(&auth_domain_lock);
173
174	hlist_for_each_entry(hp, head, hash) {
175		if (strcmp(hp->name, name)==0) {
176			kref_get(&hp->ref);
177			spin_unlock(&auth_domain_lock);
178			return hp;
179		}
180	}
181	if (new)
182		hlist_add_head_rcu(&new->hash, head);
183	spin_unlock(&auth_domain_lock);
184	return new;
185}
186EXPORT_SYMBOL_GPL(auth_domain_lookup);
187
188struct auth_domain *auth_domain_find(char *name)
189{
190	struct auth_domain *hp;
191	struct hlist_head *head;
192
193	head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
194
195	rcu_read_lock();
196	hlist_for_each_entry_rcu(hp, head, hash) {
197		if (strcmp(hp->name, name)==0) {
198			if (!kref_get_unless_zero(&hp->ref))
199				hp = NULL;
200			rcu_read_unlock();
201			return hp;
202		}
203	}
204	rcu_read_unlock();
205	return NULL;
206}
207EXPORT_SYMBOL_GPL(auth_domain_find);