From 9ae5743515f88f481c0e1075c21404e67d9cc197 Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Tue, 7 Apr 2009 17:01:07 +0000
Subject: [PATCH] Disable SSLv2 cipher suites by default and avoid SSLv2
 compatible client hello if no SSLv2 cipher suites are included. This
 effectively disables the broken SSLv2 use by default.

---
 CHANGES        |  6 ++++++
 ssl/s23_clnt.c | 17 +++++++++++++++++
 ssl/ssl.h      |  4 ++--
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/CHANGES b/CHANGES
index e8f1748ac7..dff85b2b6e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,12 @@
 
  Changes between 0.9.8k and 1.0  [xx XXX xxxx]
 
+  *) If no SSLv2 ciphers are used don't use an SSLv2 compatible client hello:
+     this allows the use of compression and extensions. Change default cipher
+     string to remove SSLv2 ciphersuites. This effectively avoids ancient SSLv2
+     by default unless an application cipher string requests it.
+     [Steve Henson]
+
   *) Alter match criteria in PKCS12_parse(). It used to try to use local
      key ids to find matching certificates and keys but some PKCS#12 files
      don't follow the (somewhat unwritten) rules and this strategy fails.
diff --git a/ssl/s23_clnt.c b/ssl/s23_clnt.c
index 0912528f89..a71311e716 100644
--- a/ssl/s23_clnt.c
+++ b/ssl/s23_clnt.c
@@ -250,6 +250,20 @@ end:
 	return(ret);
 	}
 
+static int ssl23_no_ssl2_ciphers(SSL *s)
+	{
+	SSL_CIPHER *cipher;
+	STACK_OF(SSL_CIPHER) *ciphers;
+	int i;
+	ciphers = SSL_get_ciphers(s);
+	for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++)
+		{
+		cipher = sk_SSL_CIPHER_value(ciphers, i);
+		if (cipher->algorithm_ssl == SSL_SSLV2)
+			return 0;
+		}
+	return 1;
+	}
 
 static int ssl23_client_hello(SSL *s)
 	{
@@ -264,6 +278,9 @@ static int ssl23_client_hello(SSL *s)
 
 	ssl2_compat = (s->options & SSL_OP_NO_SSLv2) ? 0 : 1;
 
+	if (ssl2_compat && ssl23_no_ssl2_ciphers(s))
+		ssl2_compat = 0;
+
 	if (!(s->options & SSL_OP_NO_TLSv1))
 		{
 		version = TLS1_VERSION;
diff --git a/ssl/ssl.h b/ssl/ssl.h
index d0c42fa1d1..a9d1fa5fcc 100644
--- a/ssl/ssl.h
+++ b/ssl/ssl.h
@@ -324,8 +324,8 @@ extern "C" {
 /* The following cipher list is used by default.
  * It also is substituted when an application-defined cipher list string
  * starts with 'DEFAULT'. */
-#define SSL_DEFAULT_CIPHER_LIST	"ALL:!aNULL:!eNULL"
-/* As of OpenSSL 0.9.9, ssl_create_cipher_list() in ssl/ssl_ciph.c always
+#define SSL_DEFAULT_CIPHER_LIST	"ALL:!aNULL:!eNULL:!SSlv2"
+/* As of OpenSSL 1.0.0, ssl_create_cipher_list() in ssl/ssl_ciph.c always
  * starts with a reasonable order, and all we have to do for DEFAULT is
  * throwing out anonymous and unencrypted ciphersuites!
  * (The latter are not actually enabled by ALL, but "ALL:RSA" would enable
-- 
2.25.1