1/*
2 * linux/net/sunrpc/svcauth.c
3 *
4 * The generic interface for RPC authentication on the server side.
5 *
6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7 *
8 * CHANGES
9 * 19-Apr-2000 Chris Evans      - Security fix
10 */
11
12#include <linux/types.h>
13#include <linux/module.h>
14#include <linux/sunrpc/types.h>
15#include <linux/sunrpc/xdr.h>
16#include <linux/sunrpc/svcsock.h>
17#include <linux/sunrpc/svcauth.h>
18#include <linux/err.h>
19#include <linux/hash.h>
20
21#define RPCDBG_FACILITY	RPCDBG_AUTH
22
23
24/*
25 * Table of authenticators
26 */
27extern struct auth_ops svcauth_null;
28extern struct auth_ops svcauth_unix;
29
30static DEFINE_SPINLOCK(authtab_lock);
31static struct auth_ops	*authtab[RPC_AUTH_MAXFLAVOR] = {
32	[0] = &svcauth_null,
33	[1] = &svcauth_unix,
34};
35
36int
37svc_authenticate(struct svc_rqst *rqstp, __be32 *authp)
38{
39	rpc_authflavor_t	flavor;
40	struct auth_ops		*aops;
41
42	*authp = rpc_auth_ok;
43
44	flavor = svc_getnl(&rqstp->rq_arg.head[0]);
45
46	dprintk("svc: svc_authenticate (%d)\n", flavor);
47
48	spin_lock(&authtab_lock);
49	if (flavor >= RPC_AUTH_MAXFLAVOR || !(aops = authtab[flavor])
50			|| !try_module_get(aops->owner)) {
51		spin_unlock(&authtab_lock);
52		*authp = rpc_autherr_badcred;
53		return SVC_DENIED;
54	}
55	spin_unlock(&authtab_lock);
56
57	rqstp->rq_authop = aops;
58	return aops->accept(rqstp, authp);
59}
60
61int svc_set_client(struct svc_rqst *rqstp)
62{
63	return rqstp->rq_authop->set_client(rqstp);
64}
65
66/* A request, which was authenticated, has now executed.
67 * Time to finalise the credentials and verifier
68 * and release and resources
69 */
70int svc_authorise(struct svc_rqst *rqstp)
71{
72	struct auth_ops *aops = rqstp->rq_authop;
73	int rv = 0;
74
75	rqstp->rq_authop = NULL;
76
77	if (aops) {
78		rv = aops->release(rqstp);
79		module_put(aops->owner);
80	}
81	return rv;
82}
83
84int
85svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
86{
87	int rv = -EINVAL;
88	spin_lock(&authtab_lock);
89	if (flavor < RPC_AUTH_MAXFLAVOR && authtab[flavor] == NULL) {
90		authtab[flavor] = aops;
91		rv = 0;
92	}
93	spin_unlock(&authtab_lock);
94	return rv;
95}
96
97void
98svc_auth_unregister(rpc_authflavor_t flavor)
99{
100	spin_lock(&authtab_lock);
101	if (flavor < RPC_AUTH_MAXFLAVOR)
102		authtab[flavor] = NULL;
103	spin_unlock(&authtab_lock);
104}
105EXPORT_SYMBOL(svc_auth_unregister);
106
107/**************************************************
108 * 'auth_domains' are stored in a hash table indexed by name.
109 * When the last reference to an 'auth_domain' is dropped,
110 * the object is unhashed and freed.
111 * If auth_domain_lookup fails to find an entry, it will return
112 * it's second argument 'new'.  If this is non-null, it will
113 * have been atomically linked into the table.
114 */
115
116#define	DN_HASHBITS	6
117#define	DN_HASHMAX	(1<<DN_HASHBITS)
118#define	DN_HASHMASK	(DN_HASHMAX-1)
119
120static struct hlist_head	auth_domain_table[DN_HASHMAX];
121static spinlock_t	auth_domain_lock =
122	__SPIN_LOCK_UNLOCKED(auth_domain_lock);
123
124void auth_domain_put(struct auth_domain *dom)
125{
126	if (atomic_dec_and_lock(&dom->ref.refcount, &auth_domain_lock)) {
127		hlist_del(&dom->hash);
128		dom->flavour->domain_release(dom);
129		spin_unlock(&auth_domain_lock);
130	}
131}
132
133struct auth_domain *
134auth_domain_lookup(char *name, struct auth_domain *new)
135{
136	struct auth_domain *hp;
137	struct hlist_head *head;
138	struct hlist_node *np;
139
140	head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
141
142	spin_lock(&auth_domain_lock);
143
144	hlist_for_each_entry(hp, np, head, hash) {
145		if (strcmp(hp->name, name)==0) {
146			kref_get(&hp->ref);
147			spin_unlock(&auth_domain_lock);
148			return hp;
149		}
150	}
151	if (new)
152		hlist_add_head(&new->hash, head);
153	spin_unlock(&auth_domain_lock);
154	return new;
155}
156
157struct auth_domain *auth_domain_find(char *name)
158{
159	return auth_domain_lookup(name, NULL);
160}
161