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/selinux_netlink.h>
  20 #include <net/net_namespace.h>
  21 #include <net/netlink.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 = nlmsg_new(len, GFP_USER);
  80         if (!skb)
  81                 goto oom;
  82
  83         tmp = skb->tail;
  84         nlh = nlmsg_put(skb, 0, 0, msgtype, len, 0);
  85         if (!nlh)
  86                 goto out_kfree_skb;
  87         selnl_add_payload(nlh, len, msgtype, data);
  88         nlh->nlmsg_len = skb->tail - tmp;
  89         NETLINK_CB(skb).dst_group = SELNLGRP_AVC;
  90         netlink_broadcast(selnl, skb, 0, SELNLGRP_AVC, GFP_USER);
  91 out:
  92         return;
  93
  94 out_kfree_skb:
  95         kfree_skb(skb);
  96 oom:
  97         pr_err("SELinux:  OOM in %s\n", __func__);
  98         goto out;
  99 }
 100
 101 void selnl_notify_setenforce(int val)
 102 {
 103         selnl_notify(SELNL_MSG_SETENFORCE, &val);
 104 }
 105
 106 void selnl_notify_policyload(u32 seqno)
 107 {
 108         selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
 109 }
 110
 111 static int __init selnl_init(void)
 112 {
 113         struct netlink_kernel_cfg cfg = {
 114                 .groups = SELNLGRP_MAX,
 115                 .flags  = NL_CFG_F_NONROOT_RECV,
 116         };
 117
 118         selnl = netlink_kernel_create(&init_net, NETLINK_SELINUX, &cfg);
 119         if (selnl == NULL)
 120                 panic("SELinux:  Cannot create netlink socket.");
 121         return 0;
 122 }
 123
 124 __initcall(selnl_init);