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Commit 6745591c authored by Haishuang Yan's avatar Haishuang Yan Committed by Greg Kroah-Hartman
Browse files

ip_gre: fix parsing gre header in ipgre_err 



[ Upstream commit b0350d51f001e6edc13ee4f253b98b50b05dd401 ]

gre_parse_header stops parsing when csum_err is encountered, which means
tpi->key is undefined and ip_tunnel_lookup will return NULL improperly.

This patch introduce a NULL pointer as csum_err parameter. Even when
csum_err is encountered, it won't return error and continue parsing gre
header as expected.

Fixes: 9f57c67c ("gre: Remove support for sharing GRE protocol hook.")
Reported-by: default avatarJiri Benc <jbenc@redhat.com>
Signed-off-by: default avatarHaishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent ada2a0f1

net/ipv4/gre_demux.c

+4 −3
Original line number Diff line number Diff line
@@ -87,13 +87,14 @@ int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi, 


	options = (__be32 *)(greh + 1);

	if (greh->flags & GRE_CSUM) {

		if (skb_checksum_simple_validate(skb)) {

		if (!skb_checksum_simple_validate(skb)) {

			skb_checksum_try_convert(skb, IPPROTO_GRE, 0,

						 null_compute_pseudo);

		} else if (csum_err) {

			*csum_err = true;

			return -EINVAL;

		}



		skb_checksum_try_convert(skb, IPPROTO_GRE, 0,

					 null_compute_pseudo);

		options++;

	}

net/ipv4/ip_gre.c

+3 −6
Original line number Diff line number Diff line
@@ -232,13 +232,10 @@ static void gre_err(struct sk_buff *skb, u32 info) 
	const int type = icmp_hdr(skb)->type;

	const int code = icmp_hdr(skb)->code;

	struct tnl_ptk_info tpi;

	bool csum_err = false;



	if (gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP),

			     iph->ihl * 4) < 0) {

		if (!csum_err)		/* ignore csum errors. */

	if (gre_parse_header(skb, &tpi, NULL, htons(ETH_P_IP),

			     iph->ihl * 4) < 0)

		return;

	}



	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {

		ipv4_update_pmtu(skb, dev_net(skb->dev), info,