LXR linux/security/selinux/netlink.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Netlink event notifications for SELinux.
   4 *
   5 * Author: James Morris <jmorris@redhat.com>
   6 *
   7 * Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
   8 */
   9#include <linux/init.h>
  10#include <linux/types.h>
  11#include <linux/slab.h>
  12#include <linux/stddef.h>
  13#include <linux/kernel.h>
  14#include <linux/export.h>
  15#include <linux/skbuff.h>
  16#include <linux/selinux_netlink.h>
  17#include <net/net_namespace.h>
  18#include <net/netlink.h>
  19
  20#include "security.h"
  21
  22static struct sock *selnl __ro_after_init;
  23
  24static int selnl_msglen(int msgtype)
  25{
  26        int ret = 0;
  27
  28        switch (msgtype) {
  29        case SELNL_MSG_SETENFORCE:
  30                ret = sizeof(struct selnl_msg_setenforce);
  31                break;
  32
  33        case SELNL_MSG_POLICYLOAD:
  34                ret = sizeof(struct selnl_msg_policyload);
  35                break;
  36
  37        default:
  38                BUG();
  39        }
  40        return ret;
  41}
  42
  43static void selnl_add_payload(struct nlmsghdr *nlh, int len, int msgtype, void *data)
  44{
  45        switch (msgtype) {
  46        case SELNL_MSG_SETENFORCE: {
  47                struct selnl_msg_setenforce *msg = nlmsg_data(nlh);
  48
  49                memset(msg, 0, len);
  50                msg->val = *((int *)data);
  51                break;
  52        }
  53
  54        case SELNL_MSG_POLICYLOAD: {
  55                struct selnl_msg_policyload *msg = nlmsg_data(nlh);
  56
  57                memset(msg, 0, len);
  58                msg->seqno = *((u32 *)data);
  59                break;
  60        }
  61
  62        default:
  63                BUG();
  64        }
  65}
  66
  67static void selnl_notify(int msgtype, void *data)
  68{
  69        int len;
  70        sk_buff_data_t tmp;
  71        struct sk_buff *skb;
  72        struct nlmsghdr *nlh;
  73
  74        len = selnl_msglen(msgtype);
  75
  76        skb = nlmsg_new(len, GFP_USER);
  77        if (!skb)
  78                goto oom;
  79
  80        tmp = skb->tail;
  81        nlh = nlmsg_put(skb, 0, 0, msgtype, len, 0);
  82        if (!nlh)
  83                goto out_kfree_skb;
  84        selnl_add_payload(nlh, len, msgtype, data);
  85        nlh->nlmsg_len = skb->tail - tmp;
  86        NETLINK_CB(skb).dst_group = SELNLGRP_AVC;
  87        netlink_broadcast(selnl, skb, 0, SELNLGRP_AVC, GFP_USER);
  88out:
  89        return;
  90
  91out_kfree_skb:
  92        kfree_skb(skb);
  93oom:
  94        pr_err("SELinux:  OOM in %s\n", __func__);
  95        goto out;
  96}
  97
  98void selnl_notify_setenforce(int val)
  99{
 100        selnl_notify(SELNL_MSG_SETENFORCE, &val);
 101}
 102
 103void selnl_notify_policyload(u32 seqno)
 104{
 105        selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
 106}
 107
 108static int __init selnl_init(void)
 109{
 110        struct netlink_kernel_cfg cfg = {
 111                .groups = SELNLGRP_MAX,
 112                .flags  = NL_CFG_F_NONROOT_RECV,
 113        };
 114
 115        selnl = netlink_kernel_create(&init_net, NETLINK_SELINUX, &cfg);
 116        if (selnl == NULL)
 117                panic("SELinux:  Cannot create netlink socket.");
 118        return 0;
 119}
 120
 121__initcall(selnl_init);
 122