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Patch "gre: do not pull header in ICMP error processing" has been added to the 4.4-stable tree

PATCH [email protected] 1 participant 1 message May 16, 2016

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This is a note to let you know that I've just added the patch titled

gre: do not pull header in ICMP error processing

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
gre-do-not-pull-header-in-icmp-error-processing.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Mon May 16 11:21:32 PDT 2016

From: Jiri Benc <[email protected]>
Date: Fri, 29 Apr 2016 23:31:32 +0200
Subject: gre: do not pull header in ICMP error processing

From: Jiri Benc <[email protected]>

[ Upstream commit b7f8fe251e4609e2a437bd2c2dea01e61db6849c ]

iptunnel_pull_header expects that IP header was already pulled; with this expectation, it pulls the tunnel header. This is not true in gre_err. Furthermore, ipv4_update_pmtu and ipv4_redirect expect that skb->data points to the IP header.

We cannot pull the tunnel header in this path. It's just a matter of not calling iptunnel_pull_header - we don't need any of its effects.

Fixes bda7bb463436 ("gre: Allow multiple protocol listener for gre protocol.")
Signed-off-by Jiri Benc <[email protected]>
Signed-off-by David S. Miller <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 net/ipv4/ip_gre.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)
net/ipv4/ip_gre.c +8 -3
@@ -180,6 +180,7 @@ static __be16 tnl_flags_to_gre_flags(__b
 	return flags;
 }
 
+/* Fills in tpi and returns header length to be pulled. */
 static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 			    bool *csum_err)
 {

@@ -239,7 +240,7 @@ static int parse_gre_header(struct sk_bu
 				return -EINVAL;
 		}
 	}
-	return iptunnel_pull_header(skb, hdr_len, tpi->proto);
+	return hdr_len;
 }
 
 static void ipgre_err(struct sk_buff *skb, u32 info,

@@ -342,7 +343,7 @@ static void gre_err(struct sk_buff *skb,
 	struct tnl_ptk_info tpi;
 	bool csum_err = false;
 
-	if (parse_gre_header(skb, &tpi, &csum_err)) {
+	if (parse_gre_header(skb, &tpi, &csum_err) < 0) {
 		if (!csum_err)		/* ignore csum errors. */
 			return;
 	}

@@ -420,6 +421,7 @@ static int gre_rcv(struct sk_buff *skb)
 {
 	struct tnl_ptk_info tpi;
 	bool csum_err = false;
+	int hdr_len;
 
 #ifdef CONFIG_NET_IPGRE_BROADCAST
 	if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {

@@ -429,7 +431,10 @@ static int gre_rcv(struct sk_buff *skb)
 	}
 #endif
 
-	if (parse_gre_header(skb, &tpi, &csum_err) < 0)
+	hdr_len = parse_gre_header(skb, &tpi, &csum_err);
+	if (hdr_len < 0)
+		goto drop;
+	if (iptunnel_pull_header(skb, hdr_len, tpi.proto) < 0)
 		goto drop;
 
 	if (ipgre_rcv(skb, &tpi) == PACKET_RCVD)

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/gre-do-not-pull-header-in-icmp-error-processing.patch