linux/security/selinux/netlink.c
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   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
  26static struct sock *selnl;
  27
  28static 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
  47static 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
  71static 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);
  92out:
  93        return;
  94
  95out_kfree_skb:
  96        kfree_skb(skb);
  97oom:
  98        printk(KERN_ERR "SELinux:  OOM in %s\n", __func__);
  99        goto out;
 100}
 101
 102void selnl_notify_setenforce(int val)
 103{
 104        selnl_notify(SELNL_MSG_SETENFORCE, &val);
 105}
 106
 107void selnl_notify_policyload(u32 seqno)
 108{
 109        selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
 110}
 111
 112static 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);
 127
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