From bbcfd60e388ab9aa244d652453b52ff490be9b27 Mon Sep 17 00:00:00 2001 From: Matt Caswell Date: Wed, 17 Oct 2018 16:17:25 +0100 Subject: [PATCH 1/1] Don't artificially limit the size of the ClientHello We were setting a limit of SSL3_RT_MAX_PLAIN_LENGTH on the size of the ClientHello. AFAIK there is nothing in the standards that requires this limit. The limit goes all the way back to when support for extensions was first added for TLSv1.0. It got converted into a WPACKET max size in 1.1.1. Most likely it was originally added to avoid the complexity of having to grow the init_buf in the middle of adding extensions. With WPACKET this is irrelevant since it will grow automatically. This issue came up when an attempt was made to send a very large certificate_authorities extension in the ClientHello. We should just remove the limit. Reviewed-by: Paul Dale Reviewed-by: Viktor Dukhovni (Merged from https://github.com/openssl/openssl/pull/7424) (cherry picked from commit 7835e97b6ff5cd94a10c5aeac439f4aa145a77b2) --- ssl/statem/statem_clnt.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c index a0e495d8e8..bb2d98ea24 100644 --- a/ssl/statem/statem_clnt.c +++ b/ssl/statem/statem_clnt.c @@ -1112,13 +1112,6 @@ int tls_construct_client_hello(SSL *s, WPACKET *pkt) SSL_SESSION *sess = s->session; unsigned char *session_id; - if (!WPACKET_set_max_size(pkt, SSL3_RT_MAX_PLAIN_LENGTH)) { - /* Should not happen */ - SSLfatal(s, SSL_AD_INTERNAL_ERROR, - SSL_F_TLS_CONSTRUCT_CLIENT_HELLO, ERR_R_INTERNAL_ERROR); - return 0; - } - /* Work out what SSL/TLS/DTLS version to use */ protverr = ssl_set_client_hello_version(s); if (protverr != 0) { -- 2.34.1