| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (c) 2010 Patrick McHardy <kaber@trash.net> |
| */ |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| #include <linux/module.h> |
| #include <linux/gfp.h> |
| #include <linux/skbuff.h> |
| #include <linux/netfilter_ipv4/ip_tables.h> |
| #include <linux/netfilter_ipv6/ip6_tables.h> |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter/xt_CT.h> |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_conntrack_l4proto.h> |
| #include <net/netfilter/nf_conntrack_helper.h> |
| #include <net/netfilter/nf_conntrack_ecache.h> |
| #include <net/netfilter/nf_conntrack_timeout.h> |
| #include <net/netfilter/nf_conntrack_zones.h> |
| |
| static inline int xt_ct_target(struct sk_buff *skb, struct nf_conn *ct) |
| { |
| /* Previously seen (loopback)? Ignore. */ |
| if (skb->_nfct != 0) |
| return XT_CONTINUE; |
| |
| if (ct) { |
| atomic_inc(&ct->ct_general.use); |
| nf_ct_set(skb, ct, IP_CT_NEW); |
| } else { |
| nf_ct_set(skb, ct, IP_CT_UNTRACKED); |
| } |
| |
| return XT_CONTINUE; |
| } |
| |
| static unsigned int xt_ct_target_v0(struct sk_buff *skb, |
| const struct xt_action_param *par) |
| { |
| const struct xt_ct_target_info *info = par->targinfo; |
| struct nf_conn *ct = info->ct; |
| |
| return xt_ct_target(skb, ct); |
| } |
| |
| static unsigned int xt_ct_target_v1(struct sk_buff *skb, |
| const struct xt_action_param *par) |
| { |
| const struct xt_ct_target_info_v1 *info = par->targinfo; |
| struct nf_conn *ct = info->ct; |
| |
| return xt_ct_target(skb, ct); |
| } |
| |
| static u8 xt_ct_find_proto(const struct xt_tgchk_param *par) |
| { |
| if (par->family == NFPROTO_IPV4) { |
| const struct ipt_entry *e = par->entryinfo; |
| |
| if (e->ip.invflags & IPT_INV_PROTO) |
| return 0; |
| return e->ip.proto; |
| } else if (par->family == NFPROTO_IPV6) { |
| const struct ip6t_entry *e = par->entryinfo; |
| |
| if (e->ipv6.invflags & IP6T_INV_PROTO) |
| return 0; |
| return e->ipv6.proto; |
| } else |
| return 0; |
| } |
| |
| static int |
| xt_ct_set_helper(struct nf_conn *ct, const char *helper_name, |
| const struct xt_tgchk_param *par) |
| { |
| struct nf_conntrack_helper *helper; |
| struct nf_conn_help *help; |
| u8 proto; |
| |
| proto = xt_ct_find_proto(par); |
| if (!proto) { |
| pr_info_ratelimited("You must specify a L4 protocol and not use inversions on it\n"); |
| return -ENOENT; |
| } |
| |
| helper = nf_conntrack_helper_try_module_get(helper_name, par->family, |
| proto); |
| if (helper == NULL) { |
| pr_info_ratelimited("No such helper \"%s\"\n", helper_name); |
| return -ENOENT; |
| } |
| |
| help = nf_ct_helper_ext_add(ct, GFP_KERNEL); |
| if (help == NULL) { |
| nf_conntrack_helper_put(helper); |
| return -ENOMEM; |
| } |
| |
| help->helper = helper; |
| return 0; |
| } |
| |
| static int |
| xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par, |
| const char *timeout_name) |
| { |
| #ifdef CONFIG_NF_CONNTRACK_TIMEOUT |
| const struct nf_conntrack_l4proto *l4proto; |
| u8 proto; |
| |
| proto = xt_ct_find_proto(par); |
| if (!proto) { |
| pr_info_ratelimited("You must specify a L4 protocol and not " |
| "use inversions on it"); |
| return -EINVAL; |
| } |
| l4proto = nf_ct_l4proto_find(proto); |
| return nf_ct_set_timeout(par->net, ct, par->family, l4proto->l4proto, |
| timeout_name); |
| |
| #else |
| return -EOPNOTSUPP; |
| #endif |
| } |
| |
| static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info) |
| { |
| switch (info->flags & (XT_CT_ZONE_DIR_ORIG | |
| XT_CT_ZONE_DIR_REPL)) { |
| case XT_CT_ZONE_DIR_ORIG: |
| return NF_CT_ZONE_DIR_ORIG; |
| case XT_CT_ZONE_DIR_REPL: |
| return NF_CT_ZONE_DIR_REPL; |
| default: |
| return NF_CT_DEFAULT_ZONE_DIR; |
| } |
| } |
| |
| static int xt_ct_tg_check(const struct xt_tgchk_param *par, |
| struct xt_ct_target_info_v1 *info) |
| { |
| struct nf_conntrack_zone zone; |
| struct nf_conn_help *help; |
| struct nf_conn *ct; |
| int ret = -EOPNOTSUPP; |
| |
| if (info->flags & XT_CT_NOTRACK) { |
| ct = NULL; |
| goto out; |
| } |
| |
| #ifndef CONFIG_NF_CONNTRACK_ZONES |
| if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG | |
| XT_CT_ZONE_DIR_REPL | |
| XT_CT_ZONE_MARK)) |
| goto err1; |
| #endif |
| |
| ret = nf_ct_netns_get(par->net, par->family); |
| if (ret < 0) |
| goto err1; |
| |
| memset(&zone, 0, sizeof(zone)); |
| zone.id = info->zone; |
| zone.dir = xt_ct_flags_to_dir(info); |
| if (info->flags & XT_CT_ZONE_MARK) |
| zone.flags |= NF_CT_FLAG_MARK; |
| |
| ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL); |
| if (!ct) { |
| ret = -ENOMEM; |
| goto err2; |
| } |
| |
| ret = 0; |
| if ((info->ct_events || info->exp_events) && |
| !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events, |
| GFP_KERNEL)) { |
| ret = -EINVAL; |
| goto err3; |
| } |
| |
| if (info->helper[0]) { |
| if (strnlen(info->helper, sizeof(info->helper)) == sizeof(info->helper)) { |
| ret = -ENAMETOOLONG; |
| goto err3; |
| } |
| |
| ret = xt_ct_set_helper(ct, info->helper, par); |
| if (ret < 0) |
| goto err3; |
| } |
| |
| if (info->timeout[0]) { |
| if (strnlen(info->timeout, sizeof(info->timeout)) == sizeof(info->timeout)) { |
| ret = -ENAMETOOLONG; |
| goto err4; |
| } |
| |
| ret = xt_ct_set_timeout(ct, par, info->timeout); |
| if (ret < 0) |
| goto err4; |
| } |
| __set_bit(IPS_CONFIRMED_BIT, &ct->status); |
| nf_conntrack_get(&ct->ct_general); |
| out: |
| info->ct = ct; |
| return 0; |
| |
| err4: |
| help = nfct_help(ct); |
| if (help) |
| nf_conntrack_helper_put(help->helper); |
| err3: |
| nf_ct_tmpl_free(ct); |
| err2: |
| nf_ct_netns_put(par->net, par->family); |
| err1: |
| return ret; |
| } |
| |
| static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par) |
| { |
| struct xt_ct_target_info *info = par->targinfo; |
| struct xt_ct_target_info_v1 info_v1 = { |
| .flags = info->flags, |
| .zone = info->zone, |
| .ct_events = info->ct_events, |
| .exp_events = info->exp_events, |
| }; |
| int ret; |
| |
| if (info->flags & ~XT_CT_NOTRACK) |
| return -EINVAL; |
| |
| memcpy(info_v1.helper, info->helper, sizeof(info->helper)); |
| |
| ret = xt_ct_tg_check(par, &info_v1); |
| if (ret < 0) |
| return ret; |
| |
| info->ct = info_v1.ct; |
| |
| return ret; |
| } |
| |
| static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par) |
| { |
| struct xt_ct_target_info_v1 *info = par->targinfo; |
| |
| if (info->flags & ~XT_CT_NOTRACK) |
| return -EINVAL; |
| |
| return xt_ct_tg_check(par, par->targinfo); |
| } |
| |
| static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par) |
| { |
| struct xt_ct_target_info_v1 *info = par->targinfo; |
| |
| if (info->flags & ~XT_CT_MASK) |
| return -EINVAL; |
| |
| return xt_ct_tg_check(par, par->targinfo); |
| } |
| |
| static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par, |
| struct xt_ct_target_info_v1 *info) |
| { |
| struct nf_conn *ct = info->ct; |
| struct nf_conn_help *help; |
| |
| if (ct) { |
| help = nfct_help(ct); |
| if (help) |
| nf_conntrack_helper_put(help->helper); |
| |
| nf_ct_netns_put(par->net, par->family); |
| |
| nf_ct_destroy_timeout(ct); |
| nf_ct_put(info->ct); |
| } |
| } |
| |
| static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par) |
| { |
| struct xt_ct_target_info *info = par->targinfo; |
| struct xt_ct_target_info_v1 info_v1 = { |
| .flags = info->flags, |
| .zone = info->zone, |
| .ct_events = info->ct_events, |
| .exp_events = info->exp_events, |
| .ct = info->ct, |
| }; |
| memcpy(info_v1.helper, info->helper, sizeof(info->helper)); |
| |
| xt_ct_tg_destroy(par, &info_v1); |
| } |
| |
| static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par) |
| { |
| xt_ct_tg_destroy(par, par->targinfo); |
| } |
| |
| static struct xt_target xt_ct_tg_reg[] __read_mostly = { |
| { |
| .name = "CT", |
| .family = NFPROTO_UNSPEC, |
| .targetsize = sizeof(struct xt_ct_target_info), |
| .usersize = offsetof(struct xt_ct_target_info, ct), |
| .checkentry = xt_ct_tg_check_v0, |
| .destroy = xt_ct_tg_destroy_v0, |
| .target = xt_ct_target_v0, |
| .table = "raw", |
| .me = THIS_MODULE, |
| }, |
| { |
| .name = "CT", |
| .family = NFPROTO_UNSPEC, |
| .revision = 1, |
| .targetsize = sizeof(struct xt_ct_target_info_v1), |
| .usersize = offsetof(struct xt_ct_target_info, ct), |
| .checkentry = xt_ct_tg_check_v1, |
| .destroy = xt_ct_tg_destroy_v1, |
| .target = xt_ct_target_v1, |
| .table = "raw", |
| .me = THIS_MODULE, |
| }, |
| { |
| .name = "CT", |
| .family = NFPROTO_UNSPEC, |
| .revision = 2, |
| .targetsize = sizeof(struct xt_ct_target_info_v1), |
| .usersize = offsetof(struct xt_ct_target_info, ct), |
| .checkentry = xt_ct_tg_check_v2, |
| .destroy = xt_ct_tg_destroy_v1, |
| .target = xt_ct_target_v1, |
| .table = "raw", |
| .me = THIS_MODULE, |
| }, |
| }; |
| |
| static unsigned int |
| notrack_tg(struct sk_buff *skb, const struct xt_action_param *par) |
| { |
| /* Previously seen (loopback)? Ignore. */ |
| if (skb->_nfct != 0) |
| return XT_CONTINUE; |
| |
| nf_ct_set(skb, NULL, IP_CT_UNTRACKED); |
| |
| return XT_CONTINUE; |
| } |
| |
| static int notrack_chk(const struct xt_tgchk_param *par) |
| { |
| if (!par->net->xt.notrack_deprecated_warning) { |
| pr_info("netfilter: NOTRACK target is deprecated, " |
| "use CT instead or upgrade iptables\n"); |
| par->net->xt.notrack_deprecated_warning = true; |
| } |
| return 0; |
| } |
| |
| static struct xt_target notrack_tg_reg __read_mostly = { |
| .name = "NOTRACK", |
| .revision = 0, |
| .family = NFPROTO_UNSPEC, |
| .checkentry = notrack_chk, |
| .target = notrack_tg, |
| .table = "raw", |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init xt_ct_tg_init(void) |
| { |
| int ret; |
| |
| ret = xt_register_target(¬rack_tg_reg); |
| if (ret < 0) |
| return ret; |
| |
| ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); |
| if (ret < 0) { |
| xt_unregister_target(¬rack_tg_reg); |
| return ret; |
| } |
| return 0; |
| } |
| |
| static void __exit xt_ct_tg_exit(void) |
| { |
| xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); |
| xt_unregister_target(¬rack_tg_reg); |
| } |
| |
| module_init(xt_ct_tg_init); |
| module_exit(xt_ct_tg_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_DESCRIPTION("Xtables: connection tracking target"); |
| MODULE_ALIAS("ipt_CT"); |
| MODULE_ALIAS("ip6t_CT"); |
| MODULE_ALIAS("ipt_NOTRACK"); |
| MODULE_ALIAS("ip6t_NOTRACK"); |