From bc6e019b6ee65ff4ebf3ca272f774cf6c67db669 Mon Sep 17 00:00:00 2001
From: Stefano Brivio <sbrivio@redhat.com>
Date: Thu, 3 Jan 2019 21:43:34 +0100
Subject: [PATCH] fou: Prevent unbounded recursion in GUE error handler also
with UDP-Lite
In commit 11789039da53 ("fou: Prevent unbounded recursion in GUE error
handler"), I didn't take care of the case where UDP-Lite is encapsulated
into UDP or UDP-Lite with GUE. From a syzbot report about a possibly
similar issue with GUE on IPv6, I just realised the same thing might
happen with a UDP-Lite inner payload.
Also skip exception handling for inner UDP-Lite protocol.
Fixes: 11789039da53 ("fou: Prevent unbounded recursion in GUE error handler")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/fou.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 0c9f171fb085e..6328635410822 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -1065,7 +1065,8 @@ static int gue_err(struct sk_buff *skb, u32 info)
* recursion. Besides, this kind of encapsulation can't even be
* configured currently. Discard this.
*/
- if (guehdr->proto_ctype == IPPROTO_UDP)
+ if (guehdr->proto_ctype == IPPROTO_UDP ||
+ guehdr->proto_ctype == IPPROTO_UDPLITE)
return -EOPNOTSUPP;
skb_set_transport_header(skb, -(int)sizeof(struct icmphdr));
--
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