netlink.c revision 066286071d3542243baa68166acb779187c848b3 
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/stddef.h>
15#include <linux/kernel.h>
16#include <linux/list.h>
17#include <linux/skbuff.h>
18#include <linux/netlink.h>
19#include <linux/selinux_netlink.h>
20
21static struct sock *selnl;
22
23static int selnl_msglen(int msgtype)
24{
25	int ret = 0;
26
27	switch (msgtype) {
28	case SELNL_MSG_SETENFORCE:
29		ret = sizeof(struct selnl_msg_setenforce);
30		break;
31
32	case SELNL_MSG_POLICYLOAD:
33		ret = sizeof(struct selnl_msg_policyload);
34		break;
35
36	default:
37		BUG();
38	}
39	return ret;
40}
41
42static void selnl_add_payload(struct nlmsghdr *nlh, int len, int msgtype, void *data)
43{
44	switch (msgtype) {
45	case SELNL_MSG_SETENFORCE: {
46		struct selnl_msg_setenforce *msg = NLMSG_DATA(nlh);
47
48		memset(msg, 0, len);
49		msg->val = *((int *)data);
50		break;
51	}
52
53	case SELNL_MSG_POLICYLOAD: {
54		struct selnl_msg_policyload *msg = NLMSG_DATA(nlh);
55
56		memset(msg, 0, len);
57		msg->seqno = *((u32 *)data);
58		break;
59	}
60
61	default:
62		BUG();
63	}
64}
65
66static void selnl_notify(int msgtype, void *data)
67{
68	int len;
69	unsigned char *tmp;
70	struct sk_buff *skb;
71	struct nlmsghdr *nlh;
72
73	len = selnl_msglen(msgtype);
74
75	skb = alloc_skb(NLMSG_SPACE(len), GFP_USER);
76	if (!skb)
77		goto oom;
78
79	tmp = skb->tail;
80	nlh = NLMSG_PUT(skb, 0, 0, msgtype, len);
81	selnl_add_payload(nlh, len, msgtype, data);
82	nlh->nlmsg_len = skb->tail - tmp;
83	NETLINK_CB(skb).dst_group = SELNLGRP_AVC;
84	netlink_broadcast(selnl, skb, 0, SELNLGRP_AVC, GFP_USER);
85out:
86	return;
87
88nlmsg_failure:
89	kfree_skb(skb);
90oom:
91	printk(KERN_ERR "SELinux:  OOM in %s\n", __FUNCTION__);
92	goto out;
93}
94
95void selnl_notify_setenforce(int val)
96{
97	selnl_notify(SELNL_MSG_SETENFORCE, &val);
98}
99
100void selnl_notify_policyload(u32 seqno)
101{
102	selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
103}
104
105static int __init selnl_init(void)
106{
107	selnl = netlink_kernel_create(NETLINK_SELINUX, SELNLGRP_MAX, NULL,
108	                              THIS_MODULE);
109	if (selnl == NULL)
110		panic("SELinux:  Cannot create netlink socket.");
111	netlink_set_nonroot(NETLINK_SELINUX, NL_NONROOT_RECV);
112	return 0;
113}
114
115__initcall(selnl_init);
116