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Subject[PATCH 5.3 097/140] vxlan: check tun_info options_len properly
Date
From: Xin Long <lucien.xin@gmail.com>

[ 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>
---
drivers/net/vxlan.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2487,9 +2487,11 @@ static void vxlan_xmit_one(struct sk_buf
vni = tunnel_id_to_key32(info->key.tun_id);
ifindex = 0;
dst_cache = &info->dst_cache;
- if (info->options_len &&
- info->key.tun_flags & TUNNEL_VXLAN_OPT)
+ if (info->key.tun_flags & TUNNEL_VXLAN_OPT) {
+ 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;

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