security/smack/smack_netfilter.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Simplified MAC Kernel (smack) security module
   4  *
   5  *  This file contains the Smack netfilter implementation
   6  *
   7  *  Author:
   8  *      Casey Schaufler <casey@schaufler-ca.com>
   9  *
  10  *  Copyright (C) 2014 Casey Schaufler <casey@schaufler-ca.com>
  11  *  Copyright (C) 2014 Intel Corporation.
  12  */
  13
  14 #include <linux/netfilter_ipv4.h>
  15 #include <linux/netfilter_ipv6.h>
  16 #include <linux/netdevice.h>
  17 #include <net/inet_sock.h>
  18 #include <net/net_namespace.h>
  19 #include "smack.h"
  20
  21 static unsigned int smack_ip_output(void *priv,
  22                                         struct sk_buff *skb,
  23                                         const struct nf_hook_state *state)
  24 {
  25         struct sock *sk = skb_to_full_sk(skb);
  26         struct socket_smack *ssp;
  27         struct smack_known *skp;
  28
  29         if (sk && sk->sk_security) {
  30                 ssp = sk->sk_security;
  31                 skp = ssp->smk_out;
  32                 skb->secmark = skp->smk_secid;
  33         }
  34
  35         return NF_ACCEPT;
  36 }
  37
  38 static const struct nf_hook_ops smack_nf_ops[] = {
  39         {
  40                 .hook =         smack_ip_output,
  41                 .pf =           NFPROTO_IPV4,
  42                 .hooknum =      NF_INET_LOCAL_OUT,
  43                 .priority =     NF_IP_PRI_SELINUX_FIRST,
  44         },
  45 #if IS_ENABLED(CONFIG_IPV6)
  46         {
  47                 .hook =         smack_ip_output,
  48                 .pf =           NFPROTO_IPV6,
  49                 .hooknum =      NF_INET_LOCAL_OUT,
  50                 .priority =     NF_IP6_PRI_SELINUX_FIRST,
  51         },
  52 #endif  /* IPV6 */
  53 };
  54
  55 static int __net_init smack_nf_register(struct net *net)
  56 {
  57         return nf_register_net_hooks(net, smack_nf_ops,
  58                                      ARRAY_SIZE(smack_nf_ops));
  59 }
  60
  61 static void __net_exit smack_nf_unregister(struct net *net)
  62 {
  63         nf_unregister_net_hooks(net, smack_nf_ops, ARRAY_SIZE(smack_nf_ops));
  64 }
  65
  66 static struct pernet_operations smack_net_ops = {
  67         .init = smack_nf_register,
  68         .exit = smack_nf_unregister,
  69 };
  70
  71 static int __init smack_nf_ip_init(void)
  72 {
  73         if (smack_enabled == 0)
  74                 return 0;
  75
  76         printk(KERN_DEBUG "Smack: Registering netfilter hooks\n");
  77         return register_pernet_subsys(&smack_net_ops);
  78 }
  79
  80 __initcall(smack_nf_ip_init);