Merge branch 'GUE-error-recursion'

Stefano Brivio says:

====================
Fix two further potential unbounded recursions in GUE error handlers

Patch 1/2 takes care of preventing the issue fixed by commit 11789039
("fou: Prevent unbounded recursion in GUE error handler") also with
UDP-Lite payloads -- I just realised this might happen from a syzbot
report.

Patch 2/2 fixes the issue for both UDP and UDP-Lite on IPv6, which I also
forgot to deal with in that same commit.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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));

net/ipv6/fou6.c

@@ -131,6 +131,14 @@ static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	if (validate_gue_flags(guehdr, optlen))
 		return -EINVAL;
 
+	/* Handling exceptions for direct UDP encapsulation in GUE would lead to
+	 * recursion. Besides, this kind of encapsulation can't even be
+	 * configured currently. Discard this.
+	 */
+	if (guehdr->proto_ctype == IPPROTO_UDP ||
+	    guehdr->proto_ctype == IPPROTO_UDPLITE)
+		return -EOPNOTSUPP;
+
 	skb_set_transport_header(skb, -(int)sizeof(struct icmp6hdr));
 	ret = gue6_err_proto_handler(guehdr->proto_ctype, skb,
 				     opt, type, code, offset, info);