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: b05229f442 ("gre6: Cleanup GREv6 transmit path, call common
GRE functions")
Reported-by: syzbot+ff8e1b9f2f36481e2efc@syzkaller.appspotmail.com
Signed-off-by: Shreyansh Chouhan <chouhan.shreyansh630@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Shreyansh Chouhan 2021-08-21 12:44:25 +05:30 committed by David S. Miller
parent 1d011c4803
commit 9cf448c200

View File

@ -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);
}