| 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) 2006,2008 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 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/skbuff.h> |
| 21 | #include <linux/netfilter/x_tables.h> |
| 22 | #include <linux/netfilter/xt_CONNSECMARK.h> |
| 23 | #include <net/netfilter/nf_conntrack.h> |
| 24 | #include <net/netfilter/nf_conntrack_ecache.h> |
| 25 | |
| 26 | MODULE_LICENSE("GPL"); |
| 27 | MODULE_AUTHOR("James Morris <jmorris@redhat.com>"); |
| 28 | MODULE_DESCRIPTION("Xtables: target for copying between connection and security mark"); |
| 29 | MODULE_ALIAS("ipt_CONNSECMARK"); |
| 30 | MODULE_ALIAS("ip6t_CONNSECMARK"); |
| 31 | |
| 32 | /* |
| 33 | * If the packet has a security mark and the connection does not, copy |
| 34 | * the security mark from the packet to the connection. |
| 35 | */ |
| 36 | static void secmark_save(const struct sk_buff *skb) |
| 37 | { |
| 38 | if (skb->secmark) { |
| 39 | struct nf_conn *ct; |
| 40 | enum ip_conntrack_info ctinfo; |
| 41 | |
| 42 | ct = nf_ct_get(skb, &ctinfo); |
| 43 | if (ct && !ct->secmark) { |
| 44 | ct->secmark = skb->secmark; |
| 45 | nf_conntrack_event_cache(IPCT_SECMARK, ct); |
| 46 | } |
| 47 | } |
| 48 | } |
| 49 | |
| 50 | /* |
| 51 | * If packet has no security mark, and the connection does, restore the |
| 52 | * security mark from the connection to the packet. |
| 53 | */ |
| 54 | static void secmark_restore(struct sk_buff *skb) |
| 55 | { |
| 56 | if (!skb->secmark) { |
| 57 | const struct nf_conn *ct; |
| 58 | enum ip_conntrack_info ctinfo; |
| 59 | |
| 60 | ct = nf_ct_get(skb, &ctinfo); |
| 61 | if (ct && ct->secmark) |
| 62 | skb->secmark = ct->secmark; |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | static unsigned int |
| 67 | connsecmark_tg(struct sk_buff *skb, const struct xt_action_param *par) |
| 68 | { |
| 69 | const struct xt_connsecmark_target_info *info = par->targinfo; |
| 70 | |
| 71 | switch (info->mode) { |
| 72 | case CONNSECMARK_SAVE: |
| 73 | secmark_save(skb); |
| 74 | break; |
| 75 | |
| 76 | case CONNSECMARK_RESTORE: |
| 77 | secmark_restore(skb); |
| 78 | break; |
| 79 | |
| 80 | default: |
| 81 | BUG(); |
| 82 | } |
| 83 | |
| 84 | return XT_CONTINUE; |
| 85 | } |
| 86 | |
| 87 | static int connsecmark_tg_check(const struct xt_tgchk_param *par) |
| 88 | { |
| 89 | const struct xt_connsecmark_target_info *info = par->targinfo; |
| 90 | int ret; |
| 91 | |
| 92 | if (strcmp(par->table, "mangle") != 0 && |
| 93 | strcmp(par->table, "security") != 0) { |
| 94 | pr_info("target only valid in the \'mangle\' " |
| 95 | "or \'security\' tables, not \'%s\'.\n", par->table); |
| 96 | return -EINVAL; |
| 97 | } |
| 98 | |
| 99 | switch (info->mode) { |
| 100 | case CONNSECMARK_SAVE: |
| 101 | case CONNSECMARK_RESTORE: |
| 102 | break; |
| 103 | |
| 104 | default: |
| 105 | pr_info("invalid mode: %hu\n", info->mode); |
| 106 | return -EINVAL; |
| 107 | } |
| 108 | |
| 109 | ret = nf_ct_l3proto_try_module_get(par->family); |
| 110 | if (ret < 0) |
| 111 | pr_info("cannot load conntrack support for proto=%u\n", |
| 112 | par->family); |
| 113 | return ret; |
| 114 | } |
| 115 | |
| 116 | static void connsecmark_tg_destroy(const struct xt_tgdtor_param *par) |
| 117 | { |
| 118 | nf_ct_l3proto_module_put(par->family); |
| 119 | } |
| 120 | |
| 121 | static struct xt_target connsecmark_tg_reg __read_mostly = { |
| 122 | .name = "CONNSECMARK", |
| 123 | .revision = 0, |
| 124 | .family = NFPROTO_UNSPEC, |
| 125 | .checkentry = connsecmark_tg_check, |
| 126 | .destroy = connsecmark_tg_destroy, |
| 127 | .target = connsecmark_tg, |
| 128 | .targetsize = sizeof(struct xt_connsecmark_target_info), |
| 129 | .me = THIS_MODULE, |
| 130 | }; |
| 131 | |
| 132 | static int __init connsecmark_tg_init(void) |
| 133 | { |
| 134 | return xt_register_target(&connsecmark_tg_reg); |
| 135 | } |
| 136 | |
| 137 | static void __exit connsecmark_tg_exit(void) |
| 138 | { |
| 139 | xt_unregister_target(&connsecmark_tg_reg); |
| 140 | } |
| 141 | |
| 142 | module_init(connsecmark_tg_init); |
| 143 | module_exit(connsecmark_tg_exit); |