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Commit 68b0faa8 authored by Alvaro Neira's avatar Alvaro Neira Committed by Pablo Neira Ayuso
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netfilter: nf_tables_bridge: export nft_reject_ip*hdr_validate functions 



This patch exports the functions nft_reject_iphdr_validate and
nft_reject_ip6hdr_validate to use it in follow up patches.
These functions check if the IPv4/IPv6 header is correct.

Signed-off-by: default avatarAlvaro Neira Ayuso <alvaroneay@gmail.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent c41884ce

include/net/netfilter/nf_tables_bridge.h

0 → 100644
+7 −0
Original line number Diff line number Diff line 
#ifndef _NET_NF_TABLES_BRIDGE_H

#define _NET_NF_TABLES_BRIDGE_H



int nft_bridge_iphdr_validate(struct sk_buff *skb);

int nft_bridge_ip6hdr_validate(struct sk_buff *skb);



#endif /* _NET_NF_TABLES_BRIDGE_H */

net/bridge/netfilter/nf_tables_bridge.c

+48 −0
Original line number Diff line number Diff line
@@ -13,6 +13,54 @@ 
#include <linux/module.h>

#include <linux/netfilter_bridge.h>

#include <net/netfilter/nf_tables.h>

#include <net/netfilter/nf_tables_bridge.h>

#include <linux/ip.h>

#include <linux/ipv6.h>



int nft_bridge_iphdr_validate(struct sk_buff *skb)

{

	struct iphdr *iph;

	u32 len;



	if (!pskb_may_pull(skb, sizeof(struct iphdr)))

		return 0;



	iph = ip_hdr(skb);

	if (iph->ihl < 5 || iph->version != 4)

		return 0;



	len = ntohs(iph->tot_len);

	if (skb->len < len)

		return 0;

	else if (len < (iph->ihl*4))

		return 0;



	if (!pskb_may_pull(skb, iph->ihl*4))

		return 0;



	return 1;

}

EXPORT_SYMBOL_GPL(nft_bridge_iphdr_validate);



int nft_bridge_ip6hdr_validate(struct sk_buff *skb)

{

	struct ipv6hdr *hdr;

	u32 pkt_len;



	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))

		return 0;



	hdr = ipv6_hdr(skb);

	if (hdr->version != 6)

		return 0;



	pkt_len = ntohs(hdr->payload_len);

	if (pkt_len + sizeof(struct ipv6hdr) > skb->len)

		return 0;



	return 1;

}

EXPORT_SYMBOL_GPL(nft_bridge_ip6hdr_validate);



static unsigned int

nft_do_chain_bridge(const struct nf_hook_ops *ops,

net/bridge/netfilter/nft_reject_bridge.c

+5 −47
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/netfilter/nf_tables.h>

#include <net/netfilter/nf_tables.h>

#include <net/netfilter/nft_reject.h>

#include <net/netfilter/nf_tables_bridge.h>

#include <net/netfilter/ipv4/nf_reject.h>

#include <net/netfilter/ipv6/nf_reject.h>

#include <linux/ip.h>
@@ -35,30 +36,6 @@ static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb, 
	skb_pull(nskb, ETH_HLEN);

}



static int nft_reject_iphdr_validate(struct sk_buff *oldskb)

{

	struct iphdr *iph;

	u32 len;



	if (!pskb_may_pull(oldskb, sizeof(struct iphdr)))

		return 0;



	iph = ip_hdr(oldskb);

	if (iph->ihl < 5 || iph->version != 4)

		return 0;



	len = ntohs(iph->tot_len);

	if (oldskb->len < len)

		return 0;

	else if (len < (iph->ihl*4))

		return 0;



	if (!pskb_may_pull(oldskb, iph->ihl*4))

		return 0;



	return 1;

}



static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook)

{

	struct sk_buff *nskb;
@@ -66,7 +43,7 @@ static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook) 
	const struct tcphdr *oth;

	struct tcphdr _oth;



	if (!nft_reject_iphdr_validate(oldskb))

	if (!nft_bridge_iphdr_validate(oldskb))

		return;



	oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
@@ -101,7 +78,7 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, 
	void *payload;

	__wsum csum;



	if (!nft_reject_iphdr_validate(oldskb))

	if (!nft_bridge_iphdr_validate(oldskb))

		return;



	/* IP header checks: fragment. */
@@ -146,25 +123,6 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook, 
	br_deliver(br_port_get_rcu(oldskb->dev), nskb);

}



static int nft_reject_ip6hdr_validate(struct sk_buff *oldskb)

{

	struct ipv6hdr *hdr;

	u32 pkt_len;



	if (!pskb_may_pull(oldskb, sizeof(struct ipv6hdr)))

		return 0;



	hdr = ipv6_hdr(oldskb);

	if (hdr->version != 6)

		return 0;



	pkt_len = ntohs(hdr->payload_len);

	if (pkt_len + sizeof(struct ipv6hdr) > oldskb->len)

		return 0;



	return 1;

}



static void nft_reject_br_send_v6_tcp_reset(struct net *net,

					    struct sk_buff *oldskb, int hook)

{
@@ -174,7 +132,7 @@ static void nft_reject_br_send_v6_tcp_reset(struct net *net, 
	unsigned int otcplen;

	struct ipv6hdr *nip6h;



	if (!nft_reject_ip6hdr_validate(oldskb))

	if (!nft_bridge_ip6hdr_validate(oldskb))

		return;



	oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
@@ -207,7 +165,7 @@ static void nft_reject_br_send_v6_unreach(struct net *net, 
	unsigned int len;

	void *payload;



	if (!nft_reject_ip6hdr_validate(oldskb))

	if (!nft_bridge_ip6hdr_validate(oldskb))

		return;



	/* Include "As much of invoking packet as possible without the ICMPv6