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