From 6630841d9c05ae2888f729f453466c8e2f30014c Mon Sep 17 00:00:00 2001 From: tb <> Date: Tue, 19 May 2020 20:22:33 +0000 Subject: OpenBSD 6.7 errata 004 6.7/004_libssl.patch.sig original commits: CVSROOT: /cvs Module name: src Changes by: jsing@cvs.openbsd.org 2020/05/16 08:44:55 Modified files: lib/libssl : tls13_client.c Log message: Ensure that a TLSv1.3 server has provided a certificate. The RFC requires that a server always provide a certificate for authentication. Ensure that this is the case, rather than proceeding and attempting validation. In the case where validation was disabled and the server returned an empty certificate list, this would have previously resulted in a NULL pointer deference. Issue reported by otto@ ok inoguchi@ tb@ CVSROOT: /cvs Module name: src Changes by: jsing@cvs.openbsd.org 2020/05/17 08:26:15 Modified files: lib/libssl : tls13_client.c Log message: Send a decode error alert if a server provides an empty certificate list. According to RFC 8446 section 4.4.2.4, a client receiving an empty certificate list must abort the handshake with a decode error alert. ok beck@ inoguchi@ tb@ ('it rarely is the alert you'd expect it to be...') --- src/lib/libssl/tls13_client.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'src/lib/libssl/tls13_client.c') diff --git a/src/lib/libssl/tls13_client.c b/src/lib/libssl/tls13_client.c index 79318d9313..24286569b1 100644 --- a/src/lib/libssl/tls13_client.c +++ b/src/lib/libssl/tls13_client.c @@ -1,4 +1,4 @@ -/* $OpenBSD: tls13_client.c,v 1.54 2020/04/28 20:37:22 jsing Exp $ */ +/* $OpenBSD: tls13_client.c,v 1.54.4.1 2020/05/19 20:22:33 tb Exp $ */ /* * Copyright (c) 2018, 2019 Joel Sing * @@ -587,6 +587,14 @@ tls13_server_certificate_recv(struct tls13_ctx *ctx, CBS *cbs) cert = NULL; } + /* A server must always provide a non-empty certificate list. */ + if (sk_X509_num(certs) < 1) { + ctx->alert = SSL_AD_DECODE_ERROR; + tls13_set_errorx(ctx, TLS13_ERR_NO_PEER_CERTIFICATE, 0, + "peer failed to provide a certificate", NULL); + goto err; + } + /* * At this stage we still have no proof of possession. As such, it would * be preferable to keep the chain and verify once we have successfully -- cgit v1.2.3-55-g6feb