This is a note to let you know that I've just added the patch titled
gtp: fix fragmentation needed check with gso
to the 5.4-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:
gtp-fix-fragmentation-needed-check-with-gso.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 20fc6de0576798e5b43e153df2726f21bf3c32dc
Author: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Date: Sun Oct 22 22:25:18 2023 +0200
gtp: fix fragmentation needed check with gso
[ Upstream commit 4530e5b8e2dad63dcad2206232dd86e4b1489b6c ]
Call skb_gso_validate_network_len() to check if packet is over PMTU.
Fixes: 459aa660eb1d ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)")
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index 0409afe9a53d6..c2e649a4f1bf4 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -544,8 +544,9 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct net_device *dev,
rt->dst.ops->update_pmtu(&rt->dst, NULL, skb, mtu, false);
- if (!skb_is_gso(skb) && (iph->frag_off & htons(IP_DF)) &&
- mtu < ntohs(iph->tot_len)) {
+ if (iph->frag_off & htons(IP_DF) &&
+ ((!skb_is_gso(skb) && skb->len > mtu) ||
+ (skb_is_gso(skb) && !skb_gso_validate_network_len(skb, mtu)))) {
netdev_dbg(dev, "packet too big, fragmentation needed\n");
icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
htonl(mtu));
