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: v4.14.153~17
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=41a230fef787315d982dd915ef2a33a136e9a1d5;p=thirdparty%2Fkernel%2Fstable.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 2fbaa279988e2..6d26bbd190dd6 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2169,8 +2169,11 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		vni = tunnel_id_to_key32(info->key.tun_id);
 		ifindex = 0;
 		dst_cache = &info->dst_cache;
-		if (info->options_len)
+		if (info->options_len) {
+			if (info->options_len < sizeof(*md))
+				goto drop;
 			md = ip_tunnel_info_opts(info);
+		}
 		ttl = info->key.ttl;
 		tos = info->key.tos;
 		label = info->key.label;