Commit 9dfd2be8 authored by Viktor Dukhovni's avatar Viktor Dukhovni Committed by Matt Caswell
Browse files

Disable SSLv2 default build, default negotiation and weak ciphers. 



SSLv2 is by default disabled at build-time.  Builds that are not
configured with "enable-ssl2" will not support SSLv2.  Even if
"enable-ssl2" is used, users who want to negotiate SSLv2 via the
version-flexible SSLv23_method() will need to explicitly call either
of:

    SSL_CTX_clear_options(ctx, SSL_OP_NO_SSLv2);
or
    SSL_clear_options(ssl, SSL_OP_NO_SSLv2);

as appropriate.  Even if either of those is used, or the application
explicitly uses the version-specific SSLv2_method() or its client
or server variants, SSLv2 ciphers vulnerable to exhaustive search
key recovery have been removed.  Specifically, the SSLv2 40-bit
EXPORT ciphers, and SSLv2 56-bit DES are no longer available.

Mitigation for CVE-2016-0800

Reviewed-by: default avatarEmilia Käsper <emilia@openssl.org>
parent c1753084

CHANGES

+17 −0
Original line number Diff line number Diff line
@@ -4,6 +4,23 @@ 


 Changes between 1.0.2f and 1.0.2g [xx XXX xxxx]



  * Disable SSLv2 default build, default negotiation and weak ciphers.  SSLv2

    is by default disabled at build-time.  Builds that are not configured with

    "enable-ssl2" will not support SSLv2.  Even if "enable-ssl2" is used,

    users who want to negotiate SSLv2 via the version-flexible SSLv23_method()

    will need to explicitly call either of:



        SSL_CTX_clear_options(ctx, SSL_OP_NO_SSLv2);

    or

        SSL_clear_options(ssl, SSL_OP_NO_SSLv2);



    as appropriate.  Even if either of those is used, or the application

    explicitly uses the version-specific SSLv2_method() or its client and

    server variants, SSLv2 ciphers vulnerable to exhaustive search key

    recovery have been removed.  Specifically, the SSLv2 40-bit EXPORT

    ciphers, and SSLv2 56-bit DES are no longer available.

    [Viktor Dukhovni]

    

  *) Disable SRP fake user seed to address a server memory leak.



     Add a new method SRP_VBASE_get1_by_user that handles the seed properly.

Configure

+2 −1
Original line number Diff line number Diff line
@@ -784,6 +784,7 @@ my %disabled = ( # "what" => "comment" [or special keyword "experimental 
		 "sctp"           => "default",

		 "shared"         => "default",

		 "ssl-trace"	  => "default",

		 "ssl2"           => "default",

		 "store"	  => "experimental",

		 "unit-test"	  => "default",

		 "zlib"           => "default",

NEWS

+1 −1
Original line number Diff line number Diff line
@@ -7,7 +7,7 @@ 


  Major changes between OpenSSL 1.0.2f and OpenSSL 1.0.2g [under development]



      o

      o Disable SSLv2 default build, default negotiation and weak ciphers.



  Major changes between OpenSSL 1.0.2e and OpenSSL 1.0.2f [28 Jan 2016]

ssl/s2_lib.c

+6 −0
Original line number Diff line number Diff line
@@ -156,6 +156,7 @@ OPENSSL_GLOBAL const SSL_CIPHER ssl2_ciphers[] = { 
     128,

     },



# if 0

/* RC4_128_EXPORT40_WITH_MD5 */

    {

     1,
@@ -171,6 +172,7 @@ OPENSSL_GLOBAL const SSL_CIPHER ssl2_ciphers[] = { 
     40,

     128,

     },

# endif



/* RC2_128_CBC_WITH_MD5 */

    {
@@ -188,6 +190,7 @@ OPENSSL_GLOBAL const SSL_CIPHER ssl2_ciphers[] = { 
     128,

     },



# if 0

/* RC2_128_CBC_EXPORT40_WITH_MD5 */

    {

     1,
@@ -203,6 +206,7 @@ OPENSSL_GLOBAL const SSL_CIPHER ssl2_ciphers[] = { 
     40,

     128,

     },

# endif



# ifndef OPENSSL_NO_IDEA

/* IDEA_128_CBC_WITH_MD5 */
@@ -222,6 +226,7 @@ OPENSSL_GLOBAL const SSL_CIPHER ssl2_ciphers[] = { 
     },

# endif



# if 0

/* DES_64_CBC_WITH_MD5 */

    {

     1,
@@ -237,6 +242,7 @@ OPENSSL_GLOBAL const SSL_CIPHER ssl2_ciphers[] = { 
     56,

     56,

     },

# endif



/* DES_192_EDE3_CBC_WITH_MD5 */

    {

ssl/ssl_conf.c

+9 −1
Original line number Diff line number Diff line
@@ -330,11 +330,19 @@ static int cmd_Protocol(SSL_CONF_CTX *cctx, const char *value) 
        SSL_FLAG_TBL_INV("TLSv1.1", SSL_OP_NO_TLSv1_1),

        SSL_FLAG_TBL_INV("TLSv1.2", SSL_OP_NO_TLSv1_2)

    };

    int ret;

    int sslv2off;



    if (!(cctx->flags & SSL_CONF_FLAG_FILE))

        return -2;

    cctx->tbl = ssl_protocol_list;

    cctx->ntbl = sizeof(ssl_protocol_list) / sizeof(ssl_flag_tbl);

    return CONF_parse_list(value, ',', 1, ssl_set_option_list, cctx);



    sslv2off = *cctx->poptions & SSL_OP_NO_SSLv2;

    ret = CONF_parse_list(value, ',', 1, ssl_set_option_list, cctx);

    /* Never turn on SSLv2 through configuration */

    *cctx->poptions |= sslv2off;

    return ret;

}



static int cmd_Options(SSL_CONF_CTX *cctx, const char *value)