1/*
2 * NetLabel Unlabeled Support
3 *
4 * This file defines functions for dealing with unlabeled packets for the
5 * NetLabel system.  The NetLabel system manages static and dynamic label
6 * mappings for network protocols such as CIPSO and RIPSO.
7 *
8 * Author: Paul Moore <paul.moore@hp.com>
9 *
10 */
11
12/*
13 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
14 *
15 * This program is free software;  you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 *
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY;  without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
23 * the GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public License
26 * along with this program;  if not, write to the Free Software
27 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 *
29 */
30
31#include <linux/types.h>
32#include <linux/rcupdate.h>
33#include <linux/list.h>
34#include <linux/spinlock.h>
35#include <linux/socket.h>
36#include <linux/string.h>
37#include <linux/skbuff.h>
38#include <linux/audit.h>
39#include <net/sock.h>
40#include <net/netlink.h>
41#include <net/genetlink.h>
42
43#include <net/netlabel.h>
44#include <asm/bug.h>
45
46#include "netlabel_user.h"
47#include "netlabel_domainhash.h"
48#include "netlabel_unlabeled.h"
49
50/* Accept unlabeled packets flag */
51static DEFINE_SPINLOCK(netlabel_unlabel_acceptflg_lock);
52static u8 netlabel_unlabel_acceptflg = 0;
53
54/* NetLabel Generic NETLINK CIPSOv4 family */
55static struct genl_family netlbl_unlabel_gnl_family = {
56	.id = GENL_ID_GENERATE,
57	.hdrsize = 0,
58	.name = NETLBL_NLTYPE_UNLABELED_NAME,
59	.version = NETLBL_PROTO_VERSION,
60	.maxattr = NLBL_UNLABEL_A_MAX,
61};
62
63/* NetLabel Netlink attribute policy */
64static const struct nla_policy netlbl_unlabel_genl_policy[NLBL_UNLABEL_A_MAX + 1] = {
65	[NLBL_UNLABEL_A_ACPTFLG] = { .type = NLA_U8 },
66};
67
68/*
69 * Helper Functions
70 */
71
72/**
73 * netlbl_unlabel_acceptflg_set - Set the unlabeled accept flag
74 * @value: desired value
75 * @audit_info: NetLabel audit information
76 *
77 * Description:
78 * Set the value of the unlabeled accept flag to @value.
79 *
80 */
81static void netlbl_unlabel_acceptflg_set(u8 value,
82					 struct netlbl_audit *audit_info)
83{
84	struct audit_buffer *audit_buf;
85	u8 old_val;
86
87	rcu_read_lock();
88	old_val = netlabel_unlabel_acceptflg;
89	spin_lock(&netlabel_unlabel_acceptflg_lock);
90	netlabel_unlabel_acceptflg = value;
91	spin_unlock(&netlabel_unlabel_acceptflg_lock);
92	rcu_read_unlock();
93
94	audit_buf = netlbl_audit_start_common(AUDIT_MAC_UNLBL_ALLOW,
95					      audit_info);
96	if (audit_buf != NULL) {
97		audit_log_format(audit_buf,
98				 " unlbl_accept=%u old=%u", value, old_val);
99		audit_log_end(audit_buf);
100	}
101}
102
103/*
104 * NetLabel Command Handlers
105 */
106
107/**
108 * netlbl_unlabel_accept - Handle an ACCEPT message
109 * @skb: the NETLINK buffer
110 * @info: the Generic NETLINK info block
111 *
112 * Description:
113 * Process a user generated ACCEPT message and set the accept flag accordingly.
114 * Returns zero on success, negative values on failure.
115 *
116 */
117static int netlbl_unlabel_accept(struct sk_buff *skb, struct genl_info *info)
118{
119	u8 value;
120	struct netlbl_audit audit_info;
121
122	if (info->attrs[NLBL_UNLABEL_A_ACPTFLG]) {
123		value = nla_get_u8(info->attrs[NLBL_UNLABEL_A_ACPTFLG]);
124		if (value == 1 || value == 0) {
125			netlbl_netlink_auditinfo(skb, &audit_info);
126			netlbl_unlabel_acceptflg_set(value, &audit_info);
127			return 0;
128		}
129	}
130
131	return -EINVAL;
132}
133
134/**
135 * netlbl_unlabel_list - Handle a LIST message
136 * @skb: the NETLINK buffer
137 * @info: the Generic NETLINK info block
138 *
139 * Description:
140 * Process a user generated LIST message and respond with the current status.
141 * Returns zero on success, negative values on failure.
142 *
143 */
144static int netlbl_unlabel_list(struct sk_buff *skb, struct genl_info *info)
145{
146	int ret_val = -EINVAL;
147	struct sk_buff *ans_skb;
148	void *data;
149
150	ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
151	if (ans_skb == NULL)
152		goto list_failure;
153	data = genlmsg_put_reply(ans_skb, info, &netlbl_unlabel_gnl_family,
154				 0, NLBL_UNLABEL_C_LIST);
155	if (data == NULL) {
156		ret_val = -ENOMEM;
157		goto list_failure;
158	}
159
160	rcu_read_lock();
161	ret_val = nla_put_u8(ans_skb,
162			     NLBL_UNLABEL_A_ACPTFLG,
163			     netlabel_unlabel_acceptflg);
164	rcu_read_unlock();
165	if (ret_val != 0)
166		goto list_failure;
167
168	genlmsg_end(ans_skb, data);
169
170	ret_val = genlmsg_reply(ans_skb, info);
171	if (ret_val != 0)
172		goto list_failure;
173	return 0;
174
175list_failure:
176	kfree_skb(ans_skb);
177	return ret_val;
178}
179
180
181/*
182 * NetLabel Generic NETLINK Command Definitions
183 */
184
185static struct genl_ops netlbl_unlabel_genl_c_accept = {
186	.cmd = NLBL_UNLABEL_C_ACCEPT,
187	.flags = GENL_ADMIN_PERM,
188	.policy = netlbl_unlabel_genl_policy,
189	.doit = netlbl_unlabel_accept,
190	.dumpit = NULL,
191};
192
193static struct genl_ops netlbl_unlabel_genl_c_list = {
194	.cmd = NLBL_UNLABEL_C_LIST,
195	.flags = 0,
196	.policy = netlbl_unlabel_genl_policy,
197	.doit = netlbl_unlabel_list,
198	.dumpit = NULL,
199};
200
201
202/*
203 * NetLabel Generic NETLINK Protocol Functions
204 */
205
206/**
207 * netlbl_unlabel_genl_init - Register the Unlabeled NetLabel component
208 *
209 * Description:
210 * Register the unlabeled packet NetLabel component with the Generic NETLINK
211 * mechanism.  Returns zero on success, negative values on failure.
212 *
213 */
214int netlbl_unlabel_genl_init(void)
215{
216	int ret_val;
217
218	ret_val = genl_register_family(&netlbl_unlabel_gnl_family);
219	if (ret_val != 0)
220		return ret_val;
221
222	ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
223				    &netlbl_unlabel_genl_c_accept);
224	if (ret_val != 0)
225		return ret_val;
226
227	ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
228				    &netlbl_unlabel_genl_c_list);
229	if (ret_val != 0)
230		return ret_val;
231
232	return 0;
233}
234
235/*
236 * NetLabel KAPI Hooks
237 */
238
239/**
240 * netlbl_unlabel_getattr - Get the security attributes for an unlabled packet
241 * @secattr: the security attributes
242 *
243 * Description:
244 * Determine the security attributes, if any, for an unlabled packet and return
245 * them in @secattr.  Returns zero on success and negative values on failure.
246 *
247 */
248int netlbl_unlabel_getattr(struct netlbl_lsm_secattr *secattr)
249{
250	int ret_val;
251
252	rcu_read_lock();
253	if (netlabel_unlabel_acceptflg == 1) {
254		netlbl_secattr_init(secattr);
255		ret_val = 0;
256	} else
257		ret_val = -ENOMSG;
258	rcu_read_unlock();
259
260	return ret_val;
261}
262
263/**
264 * netlbl_unlabel_defconf - Set the default config to allow unlabeled packets
265 *
266 * Description:
267 * Set the default NetLabel configuration to allow incoming unlabeled packets
268 * and to send unlabeled network traffic by default.
269 *
270 */
271int netlbl_unlabel_defconf(void)
272{
273	int ret_val;
274	struct netlbl_dom_map *entry;
275	struct netlbl_audit audit_info;
276
277	/* Only the kernel is allowed to call this function and the only time
278	 * it is called is at bootup before the audit subsystem is reporting
279	 * messages so don't worry to much about these values. */
280	security_task_getsecid(current, &audit_info.secid);
281	audit_info.loginuid = 0;
282
283	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
284	if (entry == NULL)
285		return -ENOMEM;
286	entry->type = NETLBL_NLTYPE_UNLABELED;
287	ret_val = netlbl_domhsh_add_default(entry, &audit_info);
288	if (ret_val != 0)
289		return ret_val;
290
291	netlbl_unlabel_acceptflg_set(1, &audit_info);
292
293	return 0;
294}
295