Commit 9ae57435 authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

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.
parent c184b140

CHANGES

+6 −0
Original line number Diff line number Diff line
@@ -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.

ssl/s23_clnt.c

+17 −0
Original line number Diff line number Diff line
@@ -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;

ssl/ssl.h

+2 −2
Original line number Diff line number Diff line
@@ -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