From: Xin Long <lucien.xin@gmail.com>
Date: Mon, 28 Oct 2019 17:24:32 +0000 (+0800)
Subject: vxlan: check tun_info options_len properly
X-Git-Tag: v4.9.200~9
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0ee544c2c10dc6f7b2b29ebbe917ffad2e0591dc;p=platform%2Fkernel%2Flinux-amlogic.git

vxlan: check tun_info options_len properly

[ Upstream commit eadf52cf1852196a1363044dcda22fa5d7f296f7 ]

This patch is to improve the tun_info options_len by dropping
the skb when TUNNEL_VXLAN_OPT is set but options_len is less
than vxlan_metadata. This can void a potential out-of-bounds
access on ip_tun_info.

Fixes: ee122c79d422 ("vxlan: Flow based tunneling")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index b6ee0c1690d8..340bd98b8dbd 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2049,8 +2049,11 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		label = info->key.label;
 		udp_sum = !!(info->key.tun_flags & TUNNEL_CSUM);
 
-		if (info->options_len)
+		if (info->options_len) {
+			if (info->options_len < sizeof(*md))
+				goto drop;
 			md = ip_tunnel_info_opts(info);
+		}
 	} else {
 		md->gbp = skb->mark;
 	}