This is a note to let you know that I've just added the patch titled ip6_gre: Revert "ip6_gre: add validation for csum_start" to the 5.14-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: ip6_gre-revert-ip6_gre-add-validation-for-csum_start.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2e18327e8f11a6a18ad7315fb2e543cb8f5ff4e5 Author: Willem de Bruijn <willemb@xxxxxxxxxx> Date: Mon Sep 6 10:27:38 2021 -0400 ip6_gre: Revert "ip6_gre: add validation for csum_start" [ Upstream commit fe63339ef36bfb1cc12962015a9b254170eea057 ] This reverts commit 9cf448c200ba9935baa94e7a0964598ce947db9d. This commit was added for equivalence with a similar fix to ip_gre. That fix proved to have a bug. Upon closer inspection, ip6_gre is not susceptible to the original bug. So revert the unnecessary extra check. In short, ipgre_xmit calls skb_pull to remove ipv4 headers previously inserted by dev_hard_header. ip6gre_tunnel_xmit does not. Link: https://lore.kernel.org/netdev/CA+FuTSe+vJgTVLc9SojGuN-f9YQ+xWLPKE_S4f=f+w+_P2hgUg@xxxxxxxxxxxxxx/#t Fixes: 9cf448c200ba ("ip6_gre: add validation for csum_start") Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index 7a5e90e09363..bc224f917bbd 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -629,8 +629,6 @@ drop: static int gre_handle_offloads(struct sk_buff *skb, bool csum) { - if (csum && skb_checksum_start(skb) < skb->data) - return -EINVAL; return iptunnel_handle_offloads(skb, csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE); }