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.

diff --git a/CHANGES b/CHANGES
index e8f1748ac7222d7fa752f2358dbfcea48309a210..dff85b2b6e62020f8e4a9e56ccd3c9da34bf498d 100644 (file)
--- 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 0912528f89a144d3e359fff34859998a783c57fe..a71311e71645afca9ffd495db931eb19a99794aa 100644 (file)
--- 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 d0c42fa1d11762b0acaa796d90df51e2447f380c..a9d1fa5fccef0f3f896bb401c2b91160de173d00 100644 (file)
--- 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