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
  22 static struct sock *selnl;
  23
  24 static 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
  43 static 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
  67 static 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);
  88 out:
  89         return;
  90
  91 out_kfree_skb:
  92         kfree_skb(skb);
  93 oom:
  94         pr_err("SELinux:  OOM in %s\n", __func__);
  95         goto out;
  96 }
  97
  98 void selnl_notify_setenforce(int val)
  99 {
 100         selnl_notify(SELNL_MSG_SETENFORCE, &val);
 101 }
 102
 103 void selnl_notify_policyload(u32 seqno)
 104 {
 105         selnl_notify(SELNL_MSG_POLICYLOAD, &seqno);
 106 }
 107
 108 static 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);