From: Matt Caswell Date: Wed, 17 Oct 2018 15:17:25 +0000 (+0100) Subject: Don't artificially limit the size of the ClientHello X-Git-Tag: openssl-3.0.0-alpha1~2648 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=7835e97b6ff5cd94a10c5aeac439f4aa145a77b2;p=oweals%2Fopenssl.git 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) --- diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c index 3b6cbb76cd..53bc5ef3f4 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) {