svcauth.c revision 1da177e4c3f41524e886b7f1b8a0c1fc7321cac 
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/sched.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#define RPCDBG_FACILITY	RPCDBG_AUTH
23
24
25/*
26 * Table of authenticators
27 */
28extern struct auth_ops svcauth_null;
29extern struct auth_ops svcauth_unix;
30
31static DEFINE_SPINLOCK(authtab_lock);
32static struct auth_ops	*authtab[RPC_AUTH_MAXFLAVOR] = {
33	[0] = &svcauth_null,
34	[1] = &svcauth_unix,
35};
36
37int
38svc_authenticate(struct svc_rqst *rqstp, u32 *authp)
39{
40	rpc_authflavor_t	flavor;
41	struct auth_ops		*aops;
42
43	*authp = rpc_auth_ok;
44
45	flavor = ntohl(svc_getu32(&rqstp->rq_arg.head[0]));
46
47	dprintk("svc: svc_authenticate (%d)\n", flavor);
48
49	spin_lock(&authtab_lock);
50	if (flavor >= RPC_AUTH_MAXFLAVOR || !(aops = authtab[flavor])
51			|| !try_module_get(aops->owner)) {
52		spin_unlock(&authtab_lock);
53		*authp = rpc_autherr_badcred;
54		return SVC_DENIED;
55	}
56	spin_unlock(&authtab_lock);
57
58	rqstp->rq_authop = aops;
59	return aops->accept(rqstp, authp);
60}
61
62int svc_set_client(struct svc_rqst *rqstp)
63{
64	return rqstp->rq_authop->set_client(rqstp);
65}
66
67/* A request, which was authenticated, has now executed.
68 * Time to finalise the the credentials and verifier
69 * and release and resources
70 */
71int svc_authorise(struct svc_rqst *rqstp)
72{
73	struct auth_ops *aops = rqstp->rq_authop;
74	int rv = 0;
75
76	rqstp->rq_authop = NULL;
77
78	if (aops) {
79		rv = aops->release(rqstp);
80		module_put(aops->owner);
81	}
82	return rv;
83}
84
85int
86svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
87{
88	int rv = -EINVAL;
89	spin_lock(&authtab_lock);
90	if (flavor < RPC_AUTH_MAXFLAVOR && authtab[flavor] == NULL) {
91		authtab[flavor] = aops;
92		rv = 0;
93	}
94	spin_unlock(&authtab_lock);
95	return rv;
96}
97
98void
99svc_auth_unregister(rpc_authflavor_t flavor)
100{
101	spin_lock(&authtab_lock);
102	if (flavor < RPC_AUTH_MAXFLAVOR)
103		authtab[flavor] = NULL;
104	spin_unlock(&authtab_lock);
105}
106EXPORT_SYMBOL(svc_auth_unregister);
107
108/**************************************************
109 * cache for domain name to auth_domain
110 * Entries are only added by flavours which will normally
111 * have a structure that 'inherits' from auth_domain.
112 * e.g. when an IP -> domainname is given to  auth_unix,
113 * and the domain name doesn't exist, it will create a
114 * auth_unix_domain and add it to this hash table.
115 * If it finds the name does exist, but isn't AUTH_UNIX,
116 * it will complain.
117 */
118
119/*
120 * Auth auth_domain cache is somewhat different to other caches,
121 * largely because the entries are possibly of different types:
122 * each auth flavour has it's own type.
123 * One consequence of this that DefineCacheLookup cannot
124 * allocate a new structure as it cannot know the size.
125 * Notice that the "INIT" code fragment is quite different
126 * from other caches.  When auth_domain_lookup might be
127 * creating a new domain, the new domain is passed in
128 * complete and it is used as-is rather than being copied into
129 * another structure.
130 */
131#define	DN_HASHBITS	6
132#define	DN_HASHMAX	(1<<DN_HASHBITS)
133#define	DN_HASHMASK	(DN_HASHMAX-1)
134
135static struct cache_head	*auth_domain_table[DN_HASHMAX];
136
137static void auth_domain_drop(struct cache_head *item, struct cache_detail *cd)
138{
139	struct auth_domain *dom = container_of(item, struct auth_domain, h);
140	if (cache_put(item,cd))
141		authtab[dom->flavour]->domain_release(dom);
142}
143
144
145struct cache_detail auth_domain_cache = {
146	.hash_size	= DN_HASHMAX,
147	.hash_table	= auth_domain_table,
148	.name		= "auth.domain",
149	.cache_put	= auth_domain_drop,
150};
151
152void auth_domain_put(struct auth_domain *dom)
153{
154	auth_domain_drop(&dom->h, &auth_domain_cache);
155}
156
157static inline int auth_domain_hash(struct auth_domain *item)
158{
159	return hash_str(item->name, DN_HASHBITS);
160}
161static inline int auth_domain_match(struct auth_domain *tmp, struct auth_domain *item)
162{
163	return strcmp(tmp->name, item->name) == 0;
164}
165
166struct auth_domain *
167auth_domain_lookup(struct auth_domain *item, int set)
168{
169	struct auth_domain *tmp = NULL;
170	struct cache_head **hp, **head;
171	head = &auth_domain_cache.hash_table[auth_domain_hash(item)];
172
173	if (set)
174		write_lock(&auth_domain_cache.hash_lock);
175	else
176		read_lock(&auth_domain_cache.hash_lock);
177	for (hp=head; *hp != NULL; hp = &tmp->h.next) {
178		tmp = container_of(*hp, struct auth_domain, h);
179		if (!auth_domain_match(tmp, item))
180			continue;
181		if (!set) {
182			cache_get(&tmp->h);
183			goto out_noset;
184		}
185		*hp = tmp->h.next;
186		tmp->h.next = NULL;
187		auth_domain_drop(&tmp->h, &auth_domain_cache);
188		goto out_set;
189	}
190	/* Didn't find anything */
191	if (!set)
192		goto out_nada;
193	auth_domain_cache.entries++;
194out_set:
195	item->h.next = *head;
196	*head = &item->h;
197	cache_get(&item->h);
198	write_unlock(&auth_domain_cache.hash_lock);
199	cache_fresh(&auth_domain_cache, &item->h, item->h.expiry_time);
200	cache_get(&item->h);
201	return item;
202out_nada:
203	tmp = NULL;
204out_noset:
205	read_unlock(&auth_domain_cache.hash_lock);
206	return tmp;
207}
208
209struct auth_domain *auth_domain_find(char *name)
210{
211	struct auth_domain *rv, ad;
212
213	ad.name = name;
214	rv = auth_domain_lookup(&ad, 0);
215	return rv;
216}
217