// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Netlink event notifications for SELinux.
   *
   * Author: James Morris <jmorris@redhat.com>
   *
   * Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>

   */
  #include <linux/init.h>
  #include <linux/types.h>

  #include <linux/slab.h>

  #include <linux/stddef.h>
  #include <linux/kernel.h>

  #include <linux/export.h>

  #include <linux/skbuff.h>

  #include <linux/selinux_netlink.h>

  #include <net/net_namespace.h>

  #include <net/netlink.h>

  #include "security.h"

  static struct sock *selnl;
  
  static int selnl_msglen(int msgtype)
  {
  	int ret = 0;

  	switch (msgtype) {
  	case SELNL_MSG_SETENFORCE:
  		ret = sizeof(struct selnl_msg_setenforce);
  		break;

  	case SELNL_MSG_POLICYLOAD:
  		ret = sizeof(struct selnl_msg_policyload);
  		break;

  	default:
  		BUG();
  	}
  	return ret;
  }
  
  static void selnl_add_payload(struct nlmsghdr *nlh, int len, int msgtype, void *data)
  {
  	switch (msgtype) {
  	case SELNL_MSG_SETENFORCE: {

  		struct selnl_msg_setenforce *msg = nlmsg_data(nlh);

  		memset(msg, 0, len);
  		msg->val = *((int *)data);
  		break;
  	}

  	case SELNL_MSG_POLICYLOAD: {

  		struct selnl_msg_policyload *msg = nlmsg_data(nlh);

  		memset(msg, 0, len);
  		msg->seqno = *((u32 *)data);
  		break;
  	}
  
  	default:
  		BUG();
  	}
  }
  
  static void selnl_notify(int msgtype, void *data)
  {
  	int len;

  	sk_buff_data_t tmp;

  	struct sk_buff *skb;
  	struct nlmsghdr *nlh;

  	len = selnl_msglen(msgtype);

  	skb = nlmsg_new(len, GFP_USER);

  	if (!skb)
  		goto oom;
  
  	tmp = skb->tail;

  	nlh = nlmsg_put(skb, 0, 0, msgtype, len, 0);
  	if (!nlh)
  		goto out_kfree_skb;

  	selnl_add_payload(nlh, len, msgtype, data);
  	nlh->nlmsg_len = skb->tail - tmp;

  	NETLINK_CB(skb).dst_group = SELNLGRP_AVC;
  	netlink_broadcast(selnl, skb, 0, SELNLGRP_AVC, GFP_USER);

  out:
  	return;

  out_kfree_skb:

  	kfree_skb(skb);
  oom:

  	pr_err("SELinux:  OOM in %s
  ", __func__);

  	goto out;
  }
  
  void selnl_notify_setenforce(int val)
  {
  	selnl_notify(SELNL_MSG_SETENFORCE, &val);
  }
  
  void selnl_notify_policyload(u32 seqno)
  {
  	selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
  }
  
  static int __init selnl_init(void)
  {

  	struct netlink_kernel_cfg cfg = {
  		.groups	= SELNLGRP_MAX,

  		.flags	= NL_CFG_F_NONROOT_RECV,

  	};

  	selnl = netlink_kernel_create(&init_net, NETLINK_SELINUX, &cfg);

  	if (selnl == NULL)
  		panic("SELinux:  Cannot create netlink socket.");

  	return 0;
  }
  
  __initcall(selnl_init);