From cc5a28ea6d2a0de9bcd56f07684bdc53cdfd10af Mon Sep 17 00:00:00 2001
From: jsing <>
Date: Wed, 12 Mar 2025 14:03:55 +0000
Subject: Provide SSL_OP_NO_RENEGOTIATION and
 SSL_OP_ALLOW_CLIENT_RENEGOTIATION.

In January 2017 we added SSL_OP_NO_CLIENT_RENEGOTIATION, which results in a
SSL_AD_NO_RENEGOTIATION fatal alert if a ClientHello message is seen on an
active connection (client initiated renegotation). Then in May 2017 OpenSSL
added SSL_OP_NO_RENEGOTIATION, which results in a SSL_AD_NO_RENEGOTIATION
warning alert if a server receives a ClientHello on an active connection
(client initiated renegotation), or a client receives a HelloRequest
(server requested renegotation). This option also causes calls to
SSL_renegotiate() and SSL_renegotiate_abbreviated() to fail. Then in 2021,
OpenSSL also added SSL_OP_ALLOW_CLIENT_RENEGOTIATION, which trumps
SSL_OP_NO_RENEGOTIATION but only for incoming ClientHello messages
(apparently unsetting SSL_OP_NO_RENEGOTIATION is too hard).

Provide SSL_OP_NO_RENEGOTIATION and SSL_OP_ALLOW_CLIENT_RENEGOTIATION,
primarily to make life easier for ports. If SSL_OP_NO_CLIENT_RENEGOTIATION
is set it will take precedence and render SSL_OP_ALLOW_CLIENT_RENEGOTIATION
ineffective. The rest of the behaviour should match OpenSSL, with the
exception of ClientHellos triggering fatal alerts instead of warnings.

ok tb@
---
 src/lib/libssl/ssl_lib.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

(limited to 'src/lib/libssl/ssl_lib.c')

diff --git a/src/lib/libssl/ssl_lib.c b/src/lib/libssl/ssl_lib.c
index 63d72baf8e..ce68981493 100644
--- a/src/lib/libssl/ssl_lib.c
+++ b/src/lib/libssl/ssl_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_lib.c,v 1.330 2024/09/22 14:59:48 tb Exp $ */
+/* $OpenBSD: ssl_lib.c,v 1.331 2025/03/12 14:03:55 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1308,6 +1308,11 @@ LSSL_ALIAS(SSL_shutdown);
 int
 SSL_renegotiate(SSL *s)
 {
+	if ((s->options & SSL_OP_NO_RENEGOTIATION) != 0) {
+		SSLerror(s, SSL_R_NO_RENEGOTIATION);
+		return 0;
+	}
+
 	if (s->renegotiate == 0)
 		s->renegotiate = 1;
 
@@ -1320,6 +1325,11 @@ LSSL_ALIAS(SSL_renegotiate);
 int
 SSL_renegotiate_abbreviated(SSL *s)
 {
+	if ((s->options & SSL_OP_NO_RENEGOTIATION) != 0) {
+		SSLerror(s, SSL_R_NO_RENEGOTIATION);
+		return 0;
+	}
+
 	if (s->renegotiate == 0)
 		s->renegotiate = 1;
 
-- 
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