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 #include <net/netlink.h>
  23
  24 #include "security.h"
  25
  26 static struct sock *selnl;
  27
  28 static int selnl_msglen(int msgtype)
  29 {
  30         int ret = 0;
  31
  32         switch (msgtype) {
  33         case SELNL_MSG_SETENFORCE:
  34                 ret = sizeof(struct selnl_msg_setenforce);
  35                 break;
  36
  37         case SELNL_MSG_POLICYLOAD:
  38                 ret = sizeof(struct selnl_msg_policyload);
  39                 break;
  40
  41         default:
  42                 BUG();
  43         }
  44         return ret;
  45 }
  46
  47 static void selnl_add_payload(struct nlmsghdr *nlh, int len, int msgtype, void *data)
  48 {
  49         switch (msgtype) {
  50         case SELNL_MSG_SETENFORCE: {
  51                 struct selnl_msg_setenforce *msg = nlmsg_data(nlh);
  52
  53                 memset(msg, 0, len);
  54                 msg->val = *((int *)data);
  55                 break;
  56         }
  57
  58         case SELNL_MSG_POLICYLOAD: {
  59                 struct selnl_msg_policyload *msg = nlmsg_data(nlh);
  60
  61                 memset(msg, 0, len);
  62                 msg->seqno = *((u32 *)data);
  63                 break;
  64         }
  65
  66         default:
  67                 BUG();
  68         }
  69 }
  70
  71 static void selnl_notify(int msgtype, void *data)
  72 {
  73         int len;
  74         sk_buff_data_t tmp;
  75         struct sk_buff *skb;
  76         struct nlmsghdr *nlh;
  77
  78         len = selnl_msglen(msgtype);
  79
  80         skb = alloc_skb(NLMSG_SPACE(len), GFP_USER);
  81         if (!skb)
  82                 goto oom;
  83
  84         tmp = skb->tail;
  85         nlh = nlmsg_put(skb, 0, 0, msgtype, len, 0);
  86         if (!nlh)
  87                 goto out_kfree_skb;
  88         selnl_add_payload(nlh, len, msgtype, data);
  89         nlh->nlmsg_len = skb->tail - tmp;
  90         NETLINK_CB(skb).dst_group = SELNLGRP_AVC;
  91         netlink_broadcast(selnl, skb, 0, SELNLGRP_AVC, GFP_USER);
  92 out:
  93         return;
  94
  95 out_kfree_skb:
  96         kfree_skb(skb);
  97 oom:
  98         printk(KERN_ERR "SELinux:  OOM in %s\n", __func__);
  99         goto out;
 100 }
 101
 102 void selnl_notify_setenforce(int val)
 103 {
 104         selnl_notify(SELNL_MSG_SETENFORCE, &val);
 105 }
 106
 107 void selnl_notify_policyload(u32 seqno)
 108 {
 109         selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
 110 }
 111
 112 static int __init selnl_init(void)
 113 {
 114         struct netlink_kernel_cfg cfg = {
 115                 .groups = SELNLGRP_MAX,
 116         };
 117
 118         selnl = netlink_kernel_create(&init_net, NETLINK_SELINUX,
 119                                       THIS_MODULE, &cfg);
 120         if (selnl == NULL)
 121                 panic("SELinux:  Cannot create netlink socket.");
 122         netlink_set_nonroot(NETLINK_SELINUX, NL_NONROOT_RECV);
 123         return 0;
 124 }
 125
 126 __initcall(selnl_init);