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 "smack.h"
  21
  22 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
  23
  24 static unsigned int smack_ipv6_output(void *priv,
  25                                         struct sk_buff *skb,
  26                                         const struct nf_hook_state *state)
  27 {
  28         struct socket_smack *ssp;
  29         struct smack_known *skp;
  30
  31         if (skb && skb->sk && skb->sk->sk_security) {
  32                 ssp = skb->sk->sk_security;
  33                 skp = ssp->smk_out;
  34                 skb->secmark = skp->smk_secid;
  35         }
  36
  37         return NF_ACCEPT;
  38 }
  39 #endif  /* IPV6 */
  40
  41 static unsigned int smack_ipv4_output(void *priv,
  42                                         struct sk_buff *skb,
  43                                         const struct nf_hook_state *state)
  44 {
  45         struct socket_smack *ssp;
  46         struct smack_known *skp;
  47
  48         if (skb && skb->sk && skb->sk->sk_security) {
  49                 ssp = skb->sk->sk_security;
  50                 skp = ssp->smk_out;
  51                 skb->secmark = skp->smk_secid;
  52         }
  53
  54         return NF_ACCEPT;
  55 }
  56
  57 static struct nf_hook_ops smack_nf_ops[] = {
  58         {
  59                 .hook =         smack_ipv4_output,
  60                 .pf =           NFPROTO_IPV4,
  61                 .hooknum =      NF_INET_LOCAL_OUT,
  62                 .priority =     NF_IP_PRI_SELINUX_FIRST,
  63         },
  64 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
  65         {
  66                 .hook =         smack_ipv6_output,
  67                 .pf =           NFPROTO_IPV6,
  68                 .hooknum =      NF_INET_LOCAL_OUT,
  69                 .priority =     NF_IP6_PRI_SELINUX_FIRST,
  70         },
  71 #endif  /* IPV6 */
  72 };
  73
  74 static int __init smack_nf_ip_init(void)
  75 {
  76         int err;
  77
  78         if (smack_enabled == 0)
  79                 return 0;
  80
  81         printk(KERN_DEBUG "Smack: Registering netfilter hooks\n");
  82
  83         err = nf_register_hooks(smack_nf_ops, ARRAY_SIZE(smack_nf_ops));
  84         if (err)
  85                 pr_info("Smack: nf_register_hooks: error %d\n", err);
  86
  87         return 0;
  88 }
  89
  90 __initcall(smack_nf_ip_init);