security/smack/smack_netfilter.c

   1 /*
   2  *  Simplified MAC Kernel (smack) security module
   3  *
   4  *  This file contains the Smack netfilter implementation
   5  *
   6  *  Author:
   7  *      Casey Schaufler <casey@schaufler-ca.com>
   8  *
   9  *  Copyright (C) 2014 Casey Schaufler <casey@schaufler-ca.com>
  10  *  Copyright (C) 2014 Intel Corporation.
  11  *
  12  *      This program is free software; you can redistribute it and/or modify
  13  *      it under the terms of the GNU General Public License version 2,
  14  *      as published by the Free Software Foundation.
  15  */
  16
  17 #include <linux/netfilter_ipv4.h>
  18 #include <linux/netfilter_ipv6.h>
  19 #include <linux/netdevice.h>
  20 #include <net/inet_sock.h>
  21 #include "smack.h"
  22
  23 #if IS_ENABLED(CONFIG_IPV6)
  24
  25 static unsigned int smack_ipv6_output(void *priv,
  26                                         struct sk_buff *skb,
  27                                         const struct nf_hook_state *state)
  28 {
  29         struct sock *sk = skb_to_full_sk(skb);
  30         struct socket_smack *ssp;
  31         struct smack_known *skp;
  32
  33         if (sk && sk->sk_security) {
  34                 ssp = sk->sk_security;
  35                 skp = ssp->smk_out;
  36                 skb->secmark = skp->smk_secid;
  37         }
  38
  39         return NF_ACCEPT;
  40 }
  41 #endif  /* IPV6 */
  42
  43 static unsigned int smack_ipv4_output(void *priv,
  44                                         struct sk_buff *skb,
  45                                         const struct nf_hook_state *state)
  46 {
  47         struct sock *sk = skb_to_full_sk(skb);
  48         struct socket_smack *ssp;
  49         struct smack_known *skp;
  50
  51         if (sk && sk->sk_security) {
  52                 ssp = sk->sk_security;
  53                 skp = ssp->smk_out;
  54                 skb->secmark = skp->smk_secid;
  55         }
  56
  57         return NF_ACCEPT;
  58 }
  59
  60 static struct nf_hook_ops smack_nf_ops[] = {
  61         {
  62                 .hook =         smack_ipv4_output,
  63                 .pf =           NFPROTO_IPV4,
  64                 .hooknum =      NF_INET_LOCAL_OUT,
  65                 .priority =     NF_IP_PRI_SELINUX_FIRST,
  66         },
  67 #if IS_ENABLED(CONFIG_IPV6)
  68         {
  69                 .hook =         smack_ipv6_output,
  70                 .pf =           NFPROTO_IPV6,
  71                 .hooknum =      NF_INET_LOCAL_OUT,
  72                 .priority =     NF_IP6_PRI_SELINUX_FIRST,
  73         },
  74 #endif  /* IPV6 */
  75 };
  76
  77 static int __init smack_nf_ip_init(void)
  78 {
  79         int err;
  80
  81         if (smack_enabled == 0)
  82                 return 0;
  83
  84         printk(KERN_DEBUG "Smack: Registering netfilter hooks\n");
  85
  86         err = nf_register_hooks(smack_nf_ops, ARRAY_SIZE(smack_nf_ops));
  87         if (err)
  88                 pr_info("Smack: nf_register_hooks: error %d\n", err);
  89
  90         return 0;
  91 }
  92
  93 __initcall(smack_nf_ip_init);