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svcauth.c
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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 <[email protected]>
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
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 }
61 
62 int svc_set_client(struct svc_rqst *rqstp)
63 {
64  return rqstp->rq_authop->set_client(rqstp);
65 }
67 
68 /* A request, which was authenticated, has now executed.
69  * Time to finalise the credentials and verifier
70  * and release and resources
71  */
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
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 }
99 
100 void
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 }
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 
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 }
135 
136 struct auth_domain *
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 }
160 
161 struct auth_domain *auth_domain_find(char *name)
162 {
163  return auth_domain_lookup(name, NULL);
164 }