From: Willy Tarreau <w@1wt.eu>
Date: Fri, 5 Aug 2022 08:09:32 +0000 (+0200)
Subject: BUG/MINOR: quic: do not reject datagrams matching minimum permitted size
X-Git-Tag: v2.7-dev3~16
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=af5138fd0725a917956a7b85df9ac74f11984ceb;p=thirdparty%2Fhaproxy.git

BUG/MINOR: quic: do not reject datagrams matching minimum permitted size

The dgram length check in quic_get_dgram_dcid() rejects datagrams
matching exactly the minimum allowed length, which doesn't seem
correct. I doubt any useful packet would be that small but better
fix this to avoid confusing debugging sessions in the future.

This might be backported to 2.6.
---

diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index a6e257d7af..4046b670c6 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -6615,7 +6615,7 @@ int quic_get_dgram_dcid(unsigned char *buf, const unsigned char *end,
 	minlen = long_header ? QUIC_LONG_PACKET_MINLEN :
 		QUIC_SHORT_PACKET_MINLEN + QUIC_HAP_CID_LEN + QUIC_TLS_TAG_LEN;
 	skip = long_header ? QUIC_LONG_PACKET_DCID_OFF : QUIC_SHORT_PACKET_DCID_OFF;
-	if (end - buf <= minlen)
+	if (end - buf < minlen)
 		goto err;
 
 	buf += skip;