1 /* 2 * This module is used to copy security markings from packets 3 * to connections, and restore security markings from connections 4 * back to packets. This would normally be performed in conjunction 5 * with the SECMARK target and state match. 6 * 7 * Based somewhat on CONNMARK: 8 * Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com> 9 * by Henrik Nordstrom <hno@marasystems.com> 10 * 11 * (C) 2006 Red Hat, Inc., James Morris <jmorris@redhat.com> 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License version 2 as 15 * published by the Free Software Foundation. 16 * 17 */ 18 #include <linux/module.h> 19 #include <linux/skbuff.h> 20 #include <linux/netfilter/x_tables.h> 21 #include <linux/netfilter/xt_CONNSECMARK.h> 22 #include <net/netfilter/nf_conntrack.h> 23 #include <net/netfilter/nf_conntrack_ecache.h> 24 25 #define PFX "CONNSECMARK: " 26 27 MODULE_LICENSE("GPL"); 28 MODULE_AUTHOR("James Morris <jmorris@redhat.com>"); 29 MODULE_DESCRIPTION("ip[6]tables CONNSECMARK module"); 30 MODULE_ALIAS("ipt_CONNSECMARK"); 31 MODULE_ALIAS("ip6t_CONNSECMARK"); 32 33 /* 34 * If the packet has a security mark and the connection does not, copy 35 * the security mark from the packet to the connection. 36 */ 37 static void secmark_save(const struct sk_buff *skb) 38 { 39 if (skb->secmark) { 40 struct nf_conn *ct; 41 enum ip_conntrack_info ctinfo; 42 43 ct = nf_ct_get(skb, &ctinfo); 44 if (ct && !ct->secmark) { 45 ct->secmark = skb->secmark; 46 nf_conntrack_event_cache(IPCT_SECMARK, skb); 47 } 48 } 49 } 50 51 /* 52 * If packet has no security mark, and the connection does, restore the 53 * security mark from the connection to the packet. 54 */ 55 static void secmark_restore(struct sk_buff *skb) 56 { 57 if (!skb->secmark) { 58 struct nf_conn *ct; 59 enum ip_conntrack_info ctinfo; 60 61 ct = nf_ct_get(skb, &ctinfo); 62 if (ct && ct->secmark) 63 skb->secmark = ct->secmark; 64 } 65 } 66 67 static unsigned int 68 connsecmark_tg(struct sk_buff *skb, const struct net_device *in, 69 const struct net_device *out, unsigned int hooknum, 70 const struct xt_target *target, const void *targinfo) 71 { 72 const struct xt_connsecmark_target_info *info = targinfo; 73 74 switch (info->mode) { 75 case CONNSECMARK_SAVE: 76 secmark_save(skb); 77 break; 78 79 case CONNSECMARK_RESTORE: 80 secmark_restore(skb); 81 break; 82 83 default: 84 BUG(); 85 } 86 87 return XT_CONTINUE; 88 } 89 90 static bool 91 connsecmark_tg_check(const char *tablename, const void *entry, 92 const struct xt_target *target, void *targinfo, 93 unsigned int hook_mask) 94 { 95 const struct xt_connsecmark_target_info *info = targinfo; 96 97 switch (info->mode) { 98 case CONNSECMARK_SAVE: 99 case CONNSECMARK_RESTORE: 100 break; 101 102 default: 103 printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode); 104 return false; 105 } 106 107 if (nf_ct_l3proto_try_module_get(target->family) < 0) { 108 printk(KERN_WARNING "can't load conntrack support for " 109 "proto=%d\n", target->family); 110 return false; 111 } 112 return true; 113 } 114 115 static void 116 connsecmark_tg_destroy(const struct xt_target *target, void *targinfo) 117 { 118 nf_ct_l3proto_module_put(target->family); 119 } 120 121 static struct xt_target connsecmark_tg_reg[] __read_mostly = { 122 { 123 .name = "CONNSECMARK", 124 .family = AF_INET, 125 .checkentry = connsecmark_tg_check, 126 .destroy = connsecmark_tg_destroy, 127 .target = connsecmark_tg, 128 .targetsize = sizeof(struct xt_connsecmark_target_info), 129 .table = "mangle", 130 .me = THIS_MODULE, 131 }, 132 { 133 .name = "CONNSECMARK", 134 .family = AF_INET6, 135 .checkentry = connsecmark_tg_check, 136 .destroy = connsecmark_tg_destroy, 137 .target = connsecmark_tg, 138 .targetsize = sizeof(struct xt_connsecmark_target_info), 139 .table = "mangle", 140 .me = THIS_MODULE, 141 }, 142 }; 143 144 static int __init connsecmark_tg_init(void) 145 { 146 return xt_register_targets(connsecmark_tg_reg, 147 ARRAY_SIZE(connsecmark_tg_reg)); 148 } 149 150 static void __exit connsecmark_tg_exit(void) 151 { 152 xt_unregister_targets(connsecmark_tg_reg, 153 ARRAY_SIZE(connsecmark_tg_reg)); 154 } 155 156 module_init(connsecmark_tg_init); 157 module_exit(connsecmark_tg_exit); 158