From: Baptiste Assmann <bedis9@gmail.com>
Date: Wed, 28 Nov 2018 14:20:25 +0000 (+0100)
Subject: BUG/MINOR: ssl: ssl_sock_parse_clienthello ignores session id
X-Git-Tag: v1.9-dev9~114
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6be139f86735156384d373fb5633fc4140250f60;p=thirdparty%2Fhaproxy.git

BUG/MINOR: ssl: ssl_sock_parse_clienthello ignores session id

In ssl_sock_parse_clienthello(), the code considers that SSL Sessionid
size is '1', and then considers that the SSL cipher suite is availble
right after the session id size information.
This actually works in a single case, when the client does not send a
session id.

This patch fixes this issue by introducing the a propoer way to parse
the session id and move forward the cursor by the session id length when
required.

Need to be backported to 1.8.
---

diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index a73fb2dd97..95d12e9a09 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -1561,10 +1561,19 @@ void ssl_sock_parse_clienthello(int write_p, int version, int content_type,
 
 	/* Expect 2 bytes for protocol version (1 byte for major and 1 byte
 	 * for minor, the random, composed by 4 bytes for the unix time and
-	 * 28 bytes for unix payload, and them 1 byte for the session id. So
-	 * we jump 1 + 1 + 4 + 28 + 1 bytes.
+	 * 28 bytes for unix payload. So we jump 1 + 1 + 4 + 28.
 	 */
-	msg += 1 + 1 + 4 + 28 + 1;
+	msg += 1 + 1 + 4 + 28;
+	if (msg > end)
+		return;
+
+	/* Next, is session id:
+	 * if present, we have to jump by length + 1 for the size information
+	 * if not present, we have to jump by 1 only
+	 */
+	if (msg[0] > 0)
+		msg += msg[0];
+	msg += 1;
 	if (msg > end)
 		return;