openssl/Do-not-allow-dropping-Extended-Master-Secret-extensi.patch

68 lines
2.2 KiB
Diff

From 4b7097025305b219694dd8b04f84155cd12fb71d Mon Sep 17 00:00:00 2001
From: Tomas Mraz <tmraz@fedoraproject.org>
Date: Thu, 4 Jun 2020 11:40:29 +0200
Subject: [PATCH 018/147] Do not allow dropping Extended Master Secret
extension on renegotiaton
Abort renegotiation if server receives client hello with Extended Master
Secret extension dropped in comparison to the initial session.
Fixes #9754
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/12099)
---
include/openssl/ssl3.h | 3 +++
ssl/statem/extensions.c | 14 +++++++++++++-
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/include/openssl/ssl3.h b/include/openssl/ssl3.h
index 8d01fcc..407db0b 100644
--- a/include/openssl/ssl3.h
+++ b/include/openssl/ssl3.h
@@ -292,6 +292,9 @@ extern "C" {
# define TLS1_FLAGS_STATELESS 0x0800
+/* Set if extended master secret extension required on renegotiation */
+# define TLS1_FLAGS_REQUIRED_EXTMS 0x1000
+
# define SSL3_MT_HELLO_REQUEST 0
# define SSL3_MT_CLIENT_HELLO 1
# define SSL3_MT_SERVER_HELLO 2
diff --git a/ssl/statem/extensions.c b/ssl/statem/extensions.c
index 4ef8b41..c785ab7 100644
--- a/ssl/statem/extensions.c
+++ b/ssl/statem/extensions.c
@@ -1168,14 +1168,26 @@ static int init_etm(SSL *s, unsigned int context)
static int init_ems(SSL *s, unsigned int context)
{
- if (!s->server)
+ if (s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) {
s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS;
+ s->s3->flags |= TLS1_FLAGS_REQUIRED_EXTMS;
+ }
return 1;
}
static int final_ems(SSL *s, unsigned int context, int sent)
{
+ /*
+ * Check extended master secret extension is not dropped on
+ * renegotiation.
+ */
+ if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS)
+ && (s->s3->flags & TLS1_FLAGS_REQUIRED_EXTMS)) {
+ SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_FINAL_EMS,
+ SSL_R_INCONSISTENT_EXTMS);
+ return 0;
+ }
if (!s->server && s->hit) {
/*
* Check extended master secret extension is consistent with
--
1.8.3.1