security/selinux/netlink.c

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