summaryrefslogtreecommitdiffstats
path: root/net/sunrpc/svcauth.c
blob: aa4429d0b8106ab53479ebf6aa9419f429b2613a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/net/sunrpc/svcauth.c
 *
 * The generic interface for RPC authentication on the server side.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 *
 * CHANGES
 * 19-Apr-2000 Chris Evans      - Security fix
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/err.h>
#include <linux/hash.h>

#include <trace/events/sunrpc.h>

#include "sunrpc.h"

#define RPCDBG_FACILITY	RPCDBG_AUTH


/*
 * Table of authenticators
 */
extern struct auth_ops svcauth_null;
extern struct auth_ops svcauth_unix;
extern struct auth_ops svcauth_tls;

static struct auth_ops __rcu *authtab[RPC_AUTH_MAXFLAVOR] = {
	[RPC_AUTH_NULL] = (struct auth_ops __force __rcu *)&svcauth_null,
	[RPC_AUTH_UNIX] = (struct auth_ops __force __rcu *)&svcauth_unix,
	[RPC_AUTH_TLS]  = (struct auth_ops __force __rcu *)&svcauth_tls,
};

static struct auth_ops *
svc_get_auth_ops(rpc_authflavor_t flavor)
{
	struct auth_ops		*aops;

	if (flavor >= RPC_AUTH_MAXFLAVOR)
		return NULL;
	rcu_read_lock();
	aops = rcu_dereference(authtab[flavor]);
	if (aops != NULL && !try_module_get(aops->owner))
		aops = NULL;
	rcu_read_unlock();
	return aops;
}

static void
svc_put_auth_ops(struct auth_ops *aops)
{
	module_put(aops->owner);
}

/**
 * svc_authenticate - Initialize an outgoing credential
 * @rqstp: RPC execution context
 *
 * Return values:
 *   %SVC_OK: XDR encoding of the result can begin
 *   %SVC_DENIED: Credential or verifier is not valid
 *   %SVC_GARBAGE: Failed to decode credential or verifier
 *   %SVC_COMPLETE: GSS context lifetime event; no further action
 *   %SVC_DROP: Drop this request; no further action
 *   %SVC_CLOSE: Like drop, but also close transport connection
 */
enum svc_auth_status svc_authenticate(struct svc_rqst *rqstp)
{
	struct auth_ops *aops;
	u32 flavor;

	rqstp->rq_auth_stat = rpc_auth_ok;

	/*
	 * Decode the Call credential's flavor field. The credential's
	 * body field is decoded in the chosen ->accept method below.
	 */
	if (xdr_stream_decode_u32(&rqstp->rq_arg_stream, &flavor) < 0)
		return SVC_GARBAGE;

	aops = svc_get_auth_ops(flavor);
	if (aops == NULL) {
		rqstp->rq_auth_stat = rpc_autherr_badcred;
		return SVC_DENIED;
	}

	rqstp->rq_auth_slack = 0;
	init_svc_cred(&rqstp->rq_cred);

	rqstp->rq_authop = aops;
	return aops->accept(rqstp);
}
EXPORT_SYMBOL_GPL(svc_authenticate);

/**
 * svc_set_client - Assign an appropriate 'auth_domain' as the client
 * @rqstp: RPC execution context
 *
 * Return values:
 *   %SVC_OK: Client was found and assigned
 *   %SVC_DENY: Client was explicitly denied
 *   %SVC_DROP: Ignore this request
 *   %SVC_CLOSE: Ignore this request and close the connection
 */
enum svc_auth_status svc_set_client(struct svc_rqst *rqstp)
{
	rqstp->rq_client = NULL;
	return rqstp->rq_authop->set_client(rqstp);
}
EXPORT_SYMBOL_GPL(svc_set_client);

/**
 * svc_authorise - Finalize credentials/verifier and release resources
 * @rqstp: RPC execution context
 *
 * Returns zero on success, or a negative errno.
 */
int svc_authorise(struct svc_rqst *rqstp)
{
	struct auth_ops *aops = rqstp->rq_authop;
	int rv = 0;

	rqstp->rq_authop = NULL;

	if (aops) {
		rv = aops->release(rqstp);
		svc_put_auth_ops(aops);
	}
	return rv;
}

int
svc_auth_register(rpc_authflavor_t flavor, struct auth_ops *aops)
{
	struct auth_ops *old;
	int rv = -EINVAL;

	if (flavor < RPC_AUTH_MAXFLAVOR) {
		old = cmpxchg((struct auth_ops ** __force)&authtab[flavor], NULL, aops);
		if (old == NULL || old == aops)
			rv = 0;
	}
	return rv;
}
EXPORT_SYMBOL_GPL(svc_auth_register);

void
svc_auth_unregister(rpc_authflavor_t flavor)
{
	if (flavor < RPC_AUTH_MAXFLAVOR)
		rcu_assign_pointer(authtab[flavor], NULL);
}
EXPORT_SYMBOL_GPL(svc_auth_unregister);

/**************************************************
 * 'auth_domains' are stored in a hash table indexed by name.
 * When the last reference to an 'auth_domain' is dropped,
 * the object is unhashed and freed.
 * If auth_domain_lookup fails to find an entry, it will return
 * it's second argument 'new'.  If this is non-null, it will
 * have been atomically linked into the table.
 */

#define	DN_HASHBITS	6
#define	DN_HASHMAX	(1<<DN_HASHBITS)

static struct hlist_head	auth_domain_table[DN_HASHMAX];
static DEFINE_SPINLOCK(auth_domain_lock);

static void auth_domain_release(struct kref *kref)
	__releases(&auth_domain_lock)
{
	struct auth_domain *dom = container_of(kref, struct auth_domain, ref);

	hlist_del_rcu(&dom->hash);
	dom->flavour->domain_release(dom);
	spin_unlock(&auth_domain_lock);
}

void auth_domain_put(struct auth_domain *dom)
{
	kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock);
}
EXPORT_SYMBOL_GPL(auth_domain_put);

struct auth_domain *
auth_domain_lookup(char *name, struct auth_domain *new)
{
	struct auth_domain *hp;
	struct hlist_head *head;

	head = &auth_domain_table[hash_str(name, DN_HASHBITS)];

	spin_lock(&auth_domain_lock);

	hlist_for_each_entry(hp, head, hash) {
		if (strcmp(hp->name, name)==0) {
			kref_get(&hp->ref);
			spin_unlock(&auth_domain_lock);
			return hp;
		}
	}
	if (new)
		hlist_add_head_rcu(&new->hash, head);
	spin_unlock(&auth_domain_lock);
	return new;
}
EXPORT_SYMBOL_GPL(auth_domain_lookup);

struct auth_domain *auth_domain_find(char *name)
{
	struct auth_domain *hp;
	struct hlist_head *head;

	head = &auth_domain_table[hash_str(name, DN_HASHBITS)];

	rcu_read_lock();
	hlist_for_each_entry_rcu(hp, head, hash) {
		if (strcmp(hp->name, name)==0) {
			if (!kref_get_unless_zero(&hp->ref))
				hp = NULL;
			rcu_read_unlock();
			return hp;
		}
	}
	rcu_read_unlock();
	return NULL;
}
EXPORT_SYMBOL_GPL(auth_domain_find);

/**
 * auth_domain_cleanup - check that the auth_domain table is empty
 *
 * On module unload the auth_domain_table must be empty.  To make it
 * easier to catch bugs which don't clean up domains properly, we
 * warn if anything remains in the table at cleanup time.
 *
 * Note that we cannot proactively remove the domains at this stage.
 * The ->release() function might be in a module that has already been
 * unloaded.
 */

void auth_domain_cleanup(void)
{
	int h;
	struct auth_domain *hp;

	for (h = 0; h < DN_HASHMAX; h++)
		hlist_for_each_entry(hp, &auth_domain_table[h], hash)
			pr_warn("svc: domain %s still present at module unload.\n",
				hp->name);
}