Xtables-addons 1.8

The code here is only usable with IPv4.

configure.ac

@@ -1,5 +1,5 @@
 
-AC_INIT([xtables-addons], [1.7])
+AC_INIT([xtables-addons], [1.8])
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_MACRO_DIR([m4])
 AC_PROG_INSTALL

extensions/libxt_TEE.c

@@ -1,7 +1,7 @@
 /*
  *	"TEE" target extension for iptables
  *	Copyright © Sebastian Claßen <sebastian.classen [at] freenet.ag>, 2007
- *	Jan Engelhardt <jengelh [at] medozas de>, 2007 - 2008
+ *	Jan Engelhardt <jengelh [at] medozas de>, 2007 - 2009
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License; either
@@ -70,6 +70,35 @@ static int tee_tg_parse(int c, char **argv, int invert, unsigned int *flags,
 	return false;
 }
 
+static int tee_tg6_parse(int c, char **argv, int invert, unsigned int *flags,
+                         const void *entry, struct xt_entry_target **target)
+{
+	struct xt_tee_tginfo *info = (void *)(*target)->data;
+	const struct in6_addr *ia;
+
+	switch (c) {
+	case 'g':
+		if (*flags & FLAG_GATEWAY)
+			exit_error(PARAMETER_PROBLEM,
+			           "Cannot specify --gw more than once");
+
+		if (check_inverse(optarg, &invert, NULL, 0))
+			exit_error(PARAMETER_PROBLEM,
+			           "Unexpected \"!\" after --gateway");
+
+		ia = numeric_to_ip6addr(optarg);
+		if (ia == NULL)
+			exit_error(PARAMETER_PROBLEM,
+			           "Invalid IP address %s", optarg);
+
+		memcpy(&info->gw, ia, sizeof(*ia));
+		*flags |= FLAG_GATEWAY;
+		return true;
+	}
+
+	return false;
+}
+
 static void tee_tg_check(unsigned int flags)
 {
 	if (flags == 0)
@@ -83,9 +112,20 @@ static void tee_tg_print(const void *ip, const struct xt_entry_target *target,
 	const struct xt_tee_tginfo *info = (const void *)target->data;
 
 	if (numeric)
-		printf("TEE gw:%s ", ipaddr_to_anyname(&info->gw.in));
-	else
 		printf("TEE gw:%s ", ipaddr_to_numeric(&info->gw.in));
+	else
+		printf("TEE gw:%s ", ipaddr_to_anyname(&info->gw.in));
+}
+
+static void tee_tg6_print(const void *ip, const struct xt_entry_target *target,
+                          int numeric)
+{
+	const struct xt_tee_tginfo *info = (const void *)target->data;
+
+	if (numeric)
+		printf("TEE gw:%s ", ip6addr_to_numeric(&info->gw.in6));
+	else
+		printf("TEE gw:%s ", ip6addr_to_anyname(&info->gw.in6));
 }
 
 static void tee_tg_save(const void *ip, const struct xt_entry_target *target)
@@ -95,9 +135,18 @@ static void tee_tg_save(const void *ip, const struct xt_entry_target *target)
 	printf("--gateway %s ", ipaddr_to_numeric(&info->gw.in));
 }
 
+static void tee_tg6_save(const void *ip, const struct xt_entry_target *target)
+{
+	const struct xt_tee_tginfo *info = (const void *)target->data;
+
+	printf("--gateway %s ", ip6addr_to_numeric(&info->gw.in6));
+}
+
 static struct xtables_target tee_tg_reg = {
 	.name          = "TEE",
 	.version       = XTABLES_VERSION,
+	.revision      = 0,
+	.family        = PF_INET,
 	.size          = XT_ALIGN(sizeof(struct xt_tee_tginfo)),
 	.userspacesize = XT_ALIGN(sizeof(struct xt_tee_tginfo)),
 	.help          = tee_tg_help,
@@ -108,7 +157,23 @@ static struct xtables_target tee_tg_reg = {
 	.extra_opts    = tee_tg_opts,
 };
 
+static struct xtables_target tee_tg6_reg = {
+	.name          = "TEE",
+	.version       = XTABLES_VERSION,
+	.revision      = 0,
+	.family        = PF_INET6,
+	.size          = XT_ALIGN(sizeof(struct xt_tee_tginfo)),
+	.userspacesize = XT_ALIGN(sizeof(struct xt_tee_tginfo)),
+	.help          = tee_tg_help,
+	.parse         = tee_tg6_parse,
+	.final_check   = tee_tg_check,
+	.print         = tee_tg6_print,
+	.save          = tee_tg6_save,
+	.extra_opts    = tee_tg_opts,
+};
+
 static __attribute__((constructor)) void tee_tg_ldr(void)
 {
 	xtables_register_target(&tee_tg_reg);
+	xtables_register_target(&tee_tg6_reg);
 }

extensions/libxt_ipp2p.c

@@ -22,7 +22,7 @@
 static void ipp2p_mt_help(void)
 {
 	printf(
-	"IPP2P v%s options:\n"
+	"ipp2p v%s match options:\n"
 	"  --edk    [tcp,udp]  All known eDonkey/eMule/Overnet packets\n"
 	"  --dc     [tcp]      All known Direct Connect packets\n"
 	"  --kazaa  [tcp,udp]  All known KaZaA packets\n"
@@ -32,19 +32,10 @@ static void ipp2p_mt_help(void)
 	"  --winmx  [tcp]      All known WinMX\n"
 	"  --soul   [tcp]      All known SoulSeek\n"
 	"  --ares   [tcp]      All known Ares\n\n"
-	"EXPERIMENTAL protocols (please send feedback to: ipp2p@ipp2p.org) :\n"
+	"EXPERIMENTAL protocols:\n"
 	"  --mute   [tcp]      All known Mute packets\n"
 	"  --waste  [tcp]      All known Waste packets\n"
 	"  --xdcc   [tcp]      All known XDCC packets (only xdcc login)\n\n"
-	"DEBUG SUPPPORT, use only if you know why\n"
-	"  --debug             Generate kernel debug output, THIS WILL SLOW DOWN THE FILTER\n"
-	"\nIPP2P was intended for TCP only. Due to increasing usage of UDP we needed to change this.\n"
-	"You can now use -p udp to search UDP packets only or without -p switch to search UDP and TCP packets.\n"
-	"\nSee README included with this package for more details or visit http://www.ipp2p.org\n"
-	"\nExamples:\n"
-	" iptables -A FORWARD -m ipp2p --ipp2p -j MARK --set-mark 0x01\n"
-	" iptables -A FORWARD -p udp -m ipp2p --kazaa --bit -j DROP\n"
-	" iptables -A FORWARD -p tcp -m ipp2p --edk --soul -j DROP\n\n"
 	, IPP2P_VERSION);
 }
 

extensions/libxt_ipp2p.man

@@ -1,12 +1,12 @@
 This module matches certain packets in P2P flows. It is not
 designed to match all packets belonging to a P2P connection - 
-use IPP2P together with CONNMARK for this purpose. Also visit
-http://www.ipp2p.org for detailed information.
-
+use IPP2P together with CONNMARK for this purpose.
+.PP
 Use it together with -p tcp or -p udp to search these protocols
 only or without -p switch to search packets of both protocols.
-
-IPP2P provides the following options:
+.PP
+IPP2P provides the following options, of which one or more may be specified
+on the command line:
 .TP
 .B "--edk "
 Matches as many eDonkey/eMule packets as possible.
@@ -38,3 +38,11 @@ Matches Ares and AresLite packets. Use together with -j DROP only.
 .B "--debug "
 Prints some information about each hit into kernel logfile. May 
 produce huge logfiles so beware!
+.PP
+Note that ipp2p may not (and often, does not) identify all packets that are
+exchanged as a result of running filesharing programs.
+.PP
+There is more information on http://ipp2p.org/ , but it has not been updated
+since September 2006, and the syntax there is different from the ipp2p.c
+provided in Xtables-addons; most importantly, the --ipp2p flag was removed due
+to its ambiguity to match "all known" protocols.

extensions/libxt_portscan.man

@@ -20,7 +20,11 @@ connection was torn down after completion of the 3-way handshake.
 \fB--grscan\fR
 Match if data in the connection only flew in the direction of the remote side,
 e.g. if the connection was terminated after a locally running daemon sent its
-identification. (e.g. openssh)
+identification. (E.g. openssh, smtp, ftpd.) This may falsely trigger on
+warranted single-direction data flows, usually bulk data transfers such as
+FTP DATA connections or IRC DCC. Grab Scan Detection should only be used on
+ports where a protocol runs that is guaranteed to do a bidirectional exchange
+of bytes.
 .PP
 NOTE: Some clients (Windows XP for example) may do what looks like a SYN scan,
 so be advised to carefully use xt_portscan in conjunction with blocking rules,

extensions/xt_TEE.c

@@ -1,7 +1,7 @@
 /*
  *	"TEE" target extension for Xtables
  *	Copyright © Sebastian Claßen <sebastian.classen [at] freenet de>, 2007
- *	Jan Engelhardt <jengelh [at] medozas de>, 2007
+ *	Jan Engelhardt <jengelh [at] medozas de>, 2007 - 2008
  *
  *	based on ipt_ROUTE.c from Cédric de Launois
  *	<delaunois [at] info ucl ac be>
@@ -17,6 +17,7 @@
 #include <net/checksum.h>
 #include <net/icmp.h>
 #include <net/ip.h>
+#include <net/ip6_route.h>
 #include <net/route.h>
 #include <linux/netfilter/x_tables.h>
 
@@ -29,7 +30,7 @@ static struct nf_conn tee_track;
 #include "compat_xtables.h"
 #include "xt_TEE.h"
 
-static const union nf_inet_addr zero_address;
+static const union nf_inet_addr tee_zero_address;
 
 /*
  * Try to route the packet according to the routing keys specified in
@@ -47,21 +48,16 @@ static const union nf_inet_addr zero_address;
  *         true  - if the packet was succesfully routed to the
  *                 destination desired
  */
-static bool tee_routing(struct sk_buff *skb,
-                        const struct xt_tee_tginfo *info)
+static bool
+tee_tg_route4(struct sk_buff *skb, const struct xt_tee_tginfo *info)
 {
 	int err;
 	struct rtable *rt;
-	struct iphdr *iph = ip_hdr(skb);
-	struct flowi fl = {
-		.nl_u = {
-			.ip4_u = {
-				.daddr = info->gw.ip,
-				.tos   = RT_TOS(iph->tos),
-				.scope = RT_SCOPE_UNIVERSE,
-			}
-		}
-	};
+	struct flowi fl;
+
+	memset(&fl, 0, sizeof(fl));
+	fl.nl_u.ip4_u.daddr = info->gw.ip;
+	fl.nl_u.ip4_u.scope = RT_SCOPE_UNIVERSE;
 
 	/* Trying to route the packet using the standard routing table. */
 	err = ip_route_output_key(&init_net, &rt, &fl);
@@ -72,22 +68,14 @@ static bool tee_routing(struct sk_buff *skb,
 		return false;
 	}
 
-	/* Drop old route. */
 	dst_release(skb->dst);
-	skb->dst = NULL;
-
-	/*
-	 * Success if no oif specified or if the oif correspond to the
-	 * one desired.
-	 * [SC]: always the case, because we have no oif.
-	 */
 	skb->dst      = &rt->u.dst;
 	skb->dev      = skb->dst->dev;
 	skb->protocol = htons(ETH_P_IP);
 	return true;
 }
 
-static bool dev_hh_avail(const struct net_device *dev)
+static inline bool dev_hh_avail(const struct net_device *dev)
 {
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 23)
 	return dev->hard_header != NULL;
@@ -103,14 +91,14 @@ static bool dev_hh_avail(const struct net_device *dev)
  * POST: the packet is sent with the link layer header pushed
  *       the packet is destroyed
  */
-static void tee_ip_direct_send(struct sk_buff *skb)
+static void tee_tg_send(struct sk_buff *skb)
 {
 	const struct dst_entry *dst  = skb->dst;
 	const struct net_device *dev = dst->dev;
 	unsigned int hh_len = LL_RESERVED_SPACE(dev);
 
 	/* Be paranoid, rather than too clever. */
-	if (unlikely(skb_headroom(skb) < hh_len) && dev_hh_avail(dev)) {
+	if (unlikely(skb_headroom(skb) < hh_len && dev_hh_avail(dev))) {
 		struct sk_buff *skb2;
 
 		skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
@@ -142,7 +130,7 @@ static void tee_ip_direct_send(struct sk_buff *skb)
  * packets when we see they already have that ->nfct.
  */
 static unsigned int
-tee_tg(struct sk_buff **pskb, const struct xt_target_param *par)
+tee_tg4(struct sk_buff **pskb, const struct xt_target_param *par)
 {
 	const struct xt_tee_tginfo *info = par->targinfo;
 	struct sk_buff *skb = *pskb;
@@ -200,8 +188,78 @@ tee_tg(struct sk_buff **pskb, const struct xt_target_param *par)
 	nf_conntrack_get(skb->nfct);
 #endif
 
-	if (tee_routing(skb, info))
-		tee_ip_direct_send(skb);
+	/*
+	 * Normally, we would just use ip_local_out. Because iph->check is
+	 * already correct, we could take a shortcut and call dst_output
+	 * [forwards to ip_output] directly. ip_output however will invoke
+	 * Netfilter hooks and cause reentrancy. So we skip that too and go
+	 * directly to ip_finish_output. Since we should not do XFRM, control
+	 * passes to ip_finish_output2. That function is not exported, so it is
+	 * copied here as tee_ip_direct_send.
+	 *
+	 * We do no XFRM on the cloned packet on purpose! The choice of
+	 * iptables match options will control whether the raw packet or the
+	 * transformed version is cloned.
+	 *
+	 * Also on purpose, no fragmentation is done, to preserve the
+	 * packet as best as possible.
+	 */
+	if (tee_tg_route4(skb, info))
+		tee_tg_send(skb);
+
+	return XT_CONTINUE;
+}
+
+static bool
+tee_tg_route6(struct sk_buff *skb, const struct xt_tee_tginfo *info)
+{
+	struct dst_entry *dst;
+	struct flowi fl;
+
+	memset(&fl, 0, sizeof(fl));
+	fl.nl_u.ip6_u.daddr = info->gw.in6;
+
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 25)
+	dst = ip6_route_output(NULL, &fl);
+#else
+	dst = ip6_route_output(dev_net(skb->dev), NULL, &fl);
+#endif
+	if (dst == NULL) {
+		if (net_ratelimit())
+			printk(KERN_ERR "ip6_route_output failed for tee\n");
+		return false;
+	}
+
+	dst_release(skb->dst);
+	skb->dst      = dst;
+	skb->dev      = skb->dst->dev;
+	skb->protocol = htons(ETH_P_IPV6);
+	return true;
+}
+
+static unsigned int
+tee_tg6(struct sk_buff **pskb, const struct xt_target_param *par)
+{
+	const struct xt_tee_tginfo *info = par->targinfo;
+	struct sk_buff *skb = *pskb;
+
+	/* Try silence. */
+#ifdef WITH_CONNTRACK
+	if (skb->nfct == &tee_track.ct_general)
+		return NF_DROP;
+#endif
+
+	if ((skb = skb_copy(skb, GFP_ATOMIC)) == NULL)
+		return XT_CONTINUE;
+
+#ifdef WITH_CONNTRACK
+	nf_conntrack_put(skb->nfct);
+	skb->nfct     = &tee_track.ct_general;
+	skb->nfctinfo = IP_CT_NEW;
+	nf_conntrack_get(skb->nfct);
+#endif
+	if (tee_tg_route6(skb, info))
+		tee_tg_send(skb);
 
 	return XT_CONTINUE;
 }
@@ -211,18 +269,31 @@ static bool tee_tg_check(const struct xt_tgchk_param *par)
 	const struct xt_tee_tginfo *info = par->targinfo;
 
 	/* 0.0.0.0 and :: not allowed */
-	return memcmp(&info->gw, &zero_address, sizeof(zero_address)) != 0;
+	return memcmp(&info->gw, &tee_zero_address,
+	       sizeof(tee_zero_address)) != 0;
 }
 
-static struct xt_target tee_tg_reg __read_mostly = {
-	.name       = "TEE",
-	.revision   = 0,
-	.family     = NFPROTO_IPV4,
-	.table      = "mangle",
-	.target     = tee_tg,
-	.targetsize = sizeof(struct xt_tee_tginfo),
-	.checkentry = tee_tg_check,
-	.me         = THIS_MODULE,
+static struct xt_target tee_tg_reg[] __read_mostly = {
+	{
+		.name       = "TEE",
+		.revision   = 0,
+		.family     = NFPROTO_IPV4,
+		.table      = "mangle",
+		.target     = tee_tg4,
+		.targetsize = sizeof(struct xt_tee_tginfo),
+		.checkentry = tee_tg_check,
+		.me         = THIS_MODULE,
+	},
+	{
+		.name       = "TEE",
+		.revision   = 0,
+		.family     = NFPROTO_IPV6,
+		.table      = "mangle",
+		.target     = tee_tg6,
+		.targetsize = sizeof(struct xt_tee_tginfo),
+		.checkentry = tee_tg_check,
+		.me         = THIS_MODULE,
+	},
 };
 
 static int __init tee_tg_init(void)
@@ -241,19 +312,20 @@ static int __init tee_tg_init(void)
 	tee_track.status |= IPS_NAT_DONE_MASK;
 #endif
 
-	return xt_register_target(&tee_tg_reg);
+	return xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
 }
 
 static void __exit tee_tg_exit(void)
 {
-	xt_unregister_target(&tee_tg_reg);
+	xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
 	/* [SC]: shoud not we cleanup tee_track here? */
 }
 
 module_init(tee_tg_init);
 module_exit(tee_tg_exit);
 MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
-MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
+MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
 MODULE_DESCRIPTION("Xtables: Reroute packet copy");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("ipt_TEE");
+MODULE_ALIAS("ip6t_TEE");

extensions/xt_ipp2p.c

@@ -603,8 +603,13 @@ search_all_kazaa(const unsigned char *payload, const unsigned int plen)
 {
 	uint16_t c, end, rem;
 
-	if (plen >= 5) {
-		printk(KERN_WARNING KBUILD_MODNAME ": %s: plen (%u) < 5\n",
+	if (plen < 5)
+		/* too short for anything we test for - early bailout */
+		return 0;
+
+	if (plen >= 65535) {
+		/* Something seems _really_ fishy */
+		printk(KERN_WARNING KBUILD_MODNAME ": %s: plen (%u) >= 65535\n",
 		       __func__, plen);
 		return 0;
 	}
@@ -618,6 +623,10 @@ search_all_kazaa(const unsigned char *payload, const unsigned int plen)
 	if (memcmp(payload, "GET /", 5) != 0)
 		return 0;
 
+	if (plen < 18)
+		/* The next tests would not succeed anyhow. */
+		return 0;
+
 	end = plen - 18;
 	rem = plen - 5;
 	for (c = 5; c < end; ++c, --rem) {
@@ -828,7 +837,7 @@ ipp2p_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 	switch (ip->protocol) {
 	case IPPROTO_TCP:	/* what to do with a TCP packet */
 	{
-		const struct tcphdr *tcph = tcp_hdr(skb);
+		const struct tcphdr *tcph = (const void *)ip + ip_hdrlen(skb);
 
 		if (tcph->fin) return 0;  /* if FIN bit is set bail out */
 		if (tcph->syn) return 0;  /* if SYN bit is set bail out */
@@ -855,7 +864,7 @@ ipp2p_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 
 	case IPPROTO_UDP:	/* what to do with an UDP packet */
 	{
-		const struct udphdr *udph = udp_hdr(skb);
+		const struct udphdr *udph = (const void *)ip + ip_hdrlen(skb);
 
 		while (udp_list[i].command) {
 			if ((info->cmd & udp_list[i].command) == udp_list[i].command &&

xtables-addons.8.in

@@ -1,4 +1,4 @@
-.TH xtables\-addons 8 "v1.7 (2008\-12\-25)" "" "v1.7 (2008\-12\-25)"
+.TH xtables\-addons 8 "v1.8 (2009\-01\-10)" "" "v1.8 (2009\-01\-10)"
 .SH NAME
 Xtables\-addons - additional extensions for iptables, ip6tables, etc.
 .SH TARGETS