netlink.c revision 9785e10aedfa0fad5c1aac709dce5ada1b123783 
1/*
2 * Netlink event notifications for SELinux.
3 *
4 * Author: James Morris <jmorris@redhat.com>
5 *
6 * Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2,
10 * as published by the Free Software Foundation.
11 */
12#include <linux/init.h>
13#include <linux/types.h>
14#include <linux/slab.h>
15#include <linux/stddef.h>
16#include <linux/kernel.h>
17#include <linux/export.h>
18#include <linux/skbuff.h>
19#include <linux/netlink.h>
20#include <linux/selinux_netlink.h>
21#include <net/net_namespace.h>
22#include <net/netlink.h>
23
24#include "security.h"
25
26static struct sock *selnl;
27
28static int selnl_msglen(int msgtype)
29{
30	int ret = 0;
31
32	switch (msgtype) {
33	case SELNL_MSG_SETENFORCE:
34		ret = sizeof(struct selnl_msg_setenforce);
35		break;
36
37	case SELNL_MSG_POLICYLOAD:
38		ret = sizeof(struct selnl_msg_policyload);
39		break;
40
41	default:
42		BUG();
43	}
44	return ret;
45}
46
47static void selnl_add_payload(struct nlmsghdr *nlh, int len, int msgtype, void *data)
48{
49	switch (msgtype) {
50	case SELNL_MSG_SETENFORCE: {
51		struct selnl_msg_setenforce *msg = nlmsg_data(nlh);
52
53		memset(msg, 0, len);
54		msg->val = *((int *)data);
55		break;
56	}
57
58	case SELNL_MSG_POLICYLOAD: {
59		struct selnl_msg_policyload *msg = nlmsg_data(nlh);
60
61		memset(msg, 0, len);
62		msg->seqno = *((u32 *)data);
63		break;
64	}
65
66	default:
67		BUG();
68	}
69}
70
71static void selnl_notify(int msgtype, void *data)
72{
73	int len;
74	sk_buff_data_t tmp;
75	struct sk_buff *skb;
76	struct nlmsghdr *nlh;
77
78	len = selnl_msglen(msgtype);
79
80	skb = alloc_skb(NLMSG_SPACE(len), GFP_USER);
81	if (!skb)
82		goto oom;
83
84	tmp = skb->tail;
85	nlh = nlmsg_put(skb, 0, 0, msgtype, len, 0);
86	if (!nlh)
87		goto out_kfree_skb;
88	selnl_add_payload(nlh, len, msgtype, data);
89	nlh->nlmsg_len = skb->tail - tmp;
90	NETLINK_CB(skb).dst_group = SELNLGRP_AVC;
91	netlink_broadcast(selnl, skb, 0, SELNLGRP_AVC, GFP_USER);
92out:
93	return;
94
95out_kfree_skb:
96	kfree_skb(skb);
97oom:
98	printk(KERN_ERR "SELinux:  OOM in %s\n", __func__);
99	goto out;
100}
101
102void selnl_notify_setenforce(int val)
103{
104	selnl_notify(SELNL_MSG_SETENFORCE, &val);
105}
106
107void selnl_notify_policyload(u32 seqno)
108{
109	selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
110}
111
112static int __init selnl_init(void)
113{
114	struct netlink_kernel_cfg cfg = {
115		.groups	= SELNLGRP_MAX,
116		.flags	= NL_CFG_F_NONROOT_RECV,
117	};
118
119	selnl = netlink_kernel_create(&init_net, NETLINK_SELINUX,
120				      THIS_MODULE, &cfg);
121	if (selnl == NULL)
122		panic("SELinux:  Cannot create netlink socket.");
123	return 0;
124}
125
126__initcall(selnl_init);
127