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authorShreyansh Chouhan <chouhan.shreyansh630@gmail.com>2021-08-21 12:44:24 +0530
committerDavid S. Miller <davem@davemloft.net>2021-08-22 21:24:40 +0100
commit1d011c4803c72f3907eccfc1ec63caefb852fcbf (patch)
tree4a1f5079a0345baaee566ad60dc134fb3be704d5
parent12d125b4574bd7f602802d94d7b4a55d85aa8e25 (diff)
ip_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 ipv4 code. Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") 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>
-rw-r--r--net/ipv4/ip_gre.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 12dca0c85f3c..95419b7adf5c 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -473,6 +473,8 @@ static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
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);
}