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  */
27 extern struct auth_ops svcauth_null;
28 extern struct auth_ops svcauth_unix;
29 
30 static DEFINE_SPINLOCK(authtab_lock);
31 static struct auth_ops	*authtab[RPC_AUTH_MAXFLAVOR] = {
32 	[0] = &svcauth_null,
33 	[1] = &svcauth_unix,
34 };
35 
36 int
svc_authenticate(struct svc_rqst * rqstp,__be32 * authp)37 svc_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 EXPORT_SYMBOL_GPL(svc_authenticate);
61 
svc_set_client(struct svc_rqst * rqstp)62 int svc_set_client(struct svc_rqst *rqstp)
63 {
64 	return rqstp->rq_authop->set_client(rqstp);
65 }
66 EXPORT_SYMBOL_GPL(svc_set_client);
67 
68 /* A request, which was authenticated, has now executed.
69  * Time to finalise the credentials and verifier
70  * and release and resources
71  */
svc_authorise(struct svc_rqst * rqstp)72 int svc_authorise(struct svc_rqst *rqstp)
73 {
74 	struct auth_ops *aops = rqstp->rq_authop;
75 	int rv = 0;
76 
77 	rqstp->rq_authop = NULL;
78 
79 	if (aops) {
80 		rv = aops->release(rqstp);
81 		module_put(aops->owner);
82 	}
83 	return rv;
84 }
85 
86 int
svc_auth_register(rpc_authflavor_t flavor,struct auth_ops * aops)87 svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
88 {
89 	int rv = -EINVAL;
90 	spin_lock(&authtab_lock);
91 	if (flavor < RPC_AUTH_MAXFLAVOR && authtab[flavor] == NULL) {
92 		authtab[flavor] = aops;
93 		rv = 0;
94 	}
95 	spin_unlock(&authtab_lock);
96 	return rv;
97 }
98 EXPORT_SYMBOL_GPL(svc_auth_register);
99 
100 void
svc_auth_unregister(rpc_authflavor_t flavor)101 svc_auth_unregister(rpc_authflavor_t flavor)
102 {
103 	spin_lock(&authtab_lock);
104 	if (flavor < RPC_AUTH_MAXFLAVOR)
105 		authtab[flavor] = NULL;
106 	spin_unlock(&authtab_lock);
107 }
108 EXPORT_SYMBOL_GPL(svc_auth_unregister);
109 
110 /**************************************************
111  * 'auth_domains' are stored in a hash table indexed by name.
112  * When the last reference to an 'auth_domain' is dropped,
113  * the object is unhashed and freed.
114  * If auth_domain_lookup fails to find an entry, it will return
115  * it's second argument 'new'.  If this is non-null, it will
116  * have been atomically linked into the table.
117  */
118 
119 #define	DN_HASHBITS	6
120 #define	DN_HASHMAX	(1<<DN_HASHBITS)
121 
122 static struct hlist_head	auth_domain_table[DN_HASHMAX];
123 static spinlock_t	auth_domain_lock =
124 	__SPIN_LOCK_UNLOCKED(auth_domain_lock);
125 
auth_domain_put(struct auth_domain * dom)126 void auth_domain_put(struct auth_domain *dom)
127 {
128 	if (atomic_dec_and_lock(&dom->ref.refcount, &auth_domain_lock)) {
129 		hlist_del(&dom->hash);
130 		dom->flavour->domain_release(dom);
131 		spin_unlock(&auth_domain_lock);
132 	}
133 }
134 EXPORT_SYMBOL_GPL(auth_domain_put);
135 
136 struct auth_domain *
auth_domain_lookup(char * name,struct auth_domain * new)137 auth_domain_lookup(char *name, struct auth_domain *new)
138 {
139 	struct auth_domain *hp;
140 	struct hlist_head *head;
141 	struct hlist_node *np;
142 
143 	head = &auth_domain_table[hash_str(name, DN_HASHBITS)];
144 
145 	spin_lock(&auth_domain_lock);
146 
147 	hlist_for_each_entry(hp, np, head, hash) {
148 		if (strcmp(hp->name, name)==0) {
149 			kref_get(&hp->ref);
150 			spin_unlock(&auth_domain_lock);
151 			return hp;
152 		}
153 	}
154 	if (new)
155 		hlist_add_head(&new->hash, head);
156 	spin_unlock(&auth_domain_lock);
157 	return new;
158 }
159 EXPORT_SYMBOL_GPL(auth_domain_lookup);
160 
auth_domain_find(char * name)161 struct auth_domain *auth_domain_find(char *name)
162 {
163 	return auth_domain_lookup(name, NULL);
164 }
165 EXPORT_SYMBOL_GPL(auth_domain_find);
166