From 9cf448c200ba9935baa94e7a0964598ce947db9d Mon Sep 17 00:00:00 2001 From: Shreyansh Chouhan Date: Sat, 21 Aug 2021 12:44:25 +0530 Subject: ip6_gre: add validation for csum_start Validate csum_start in gre_handle_offloads before we call _gre_xmit so that we do not crash later when the csum_start value is used in the lco_csum function call. This patch deals with ipv6 code. Fixes: Fixes: b05229f44228 ("gre6: Cleanup GREv6 transmit path, call common GRE functions") Reported-by: syzbot+ff8e1b9f2f36481e2efc@syzkaller.appspotmail.com Signed-off-by: Shreyansh Chouhan Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller --- net/ipv6/ip6_gre.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/ipv6') diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index bc224f917bbd..7a5e90e09363 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -629,6 +629,8 @@ 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); } -- cgit v1.2.3