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