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/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
  23 #include "security.h"
  24
  25 static struct sock *selnl;
  26
  27 static int selnl_msglen(int msgtype)
  28 {
  29         int ret = 0;
  30
  31         switch (msgtype) {
  32         case SELNL_MSG_SETENFORCE:
  33                 ret = sizeof(struct selnl_msg_setenforce);
  34                 break;
  35
  36         case SELNL_MSG_POLICYLOAD:
  37                 ret = sizeof(struct selnl_msg_policyload);
  38                 break;
  39
  40         default:
  41                 BUG();
  42         }
  43         return ret;
  44 }
  45
  46 static void selnl_add_payload(struct nlmsghdr *nlh, int len, int msgtype, void *data)
  47 {
  48         switch (msgtype) {
  49         case SELNL_MSG_SETENFORCE: {
  50                 struct selnl_msg_setenforce *msg = NLMSG_DATA(nlh);
  51
  52                 memset(msg, 0, len);
  53                 msg->val = *((int *)data);
  54                 break;
  55         }
  56
  57         case SELNL_MSG_POLICYLOAD: {
  58                 struct selnl_msg_policyload *msg = NLMSG_DATA(nlh);
  59
  60                 memset(msg, 0, len);
  61                 msg->seqno = *((u32 *)data);
  62                 break;
  63         }
  64
  65         default:
  66                 BUG();
  67         }
  68 }
  69
  70 static void selnl_notify(int msgtype, void *data)
  71 {
  72         int len;
  73         sk_buff_data_t tmp;
  74         struct sk_buff *skb;
  75         struct nlmsghdr *nlh;
  76
  77         len = selnl_msglen(msgtype);
  78
  79         skb = alloc_skb(NLMSG_SPACE(len), GFP_USER);
  80         if (!skb)
  81                 goto oom;
  82
  83         tmp = skb->tail;
  84         nlh = NLMSG_PUT(skb, 0, 0, msgtype, len);
  85         selnl_add_payload(nlh, len, msgtype, data);
  86         nlh->nlmsg_len = skb->tail - tmp;
  87         NETLINK_CB(skb).dst_group = SELNLGRP_AVC;
  88         netlink_broadcast(selnl, skb, 0, SELNLGRP_AVC, GFP_USER);
  89 out:
  90         return;
  91
  92 nlmsg_failure:
  93         kfree_skb(skb);
  94 oom:
  95         printk(KERN_ERR "SELinux:  OOM in %s\n", __func__);
  96         goto out;
  97 }
  98
  99 void selnl_notify_setenforce(int val)
 100 {
 101         selnl_notify(SELNL_MSG_SETENFORCE, &val);
 102 }
 103
 104 void selnl_notify_policyload(u32 seqno)
 105 {
 106         selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
 107 }
 108
 109 static int __init selnl_init(void)
 110 {
 111         selnl = netlink_kernel_create(&init_net, NETLINK_SELINUX,
 112                                       SELNLGRP_MAX, NULL, NULL, THIS_MODULE);
 113         if (selnl == NULL)
 114                 panic("SELinux:  Cannot create netlink socket.");
 115         netlink_set_nonroot(NETLINK_SELINUX, NL_NONROOT_RECV);
 116         return 0;
 117 }
 118
 119 __initcall(selnl_init);