Commit 7890b562 authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

fix for CVE-2010-4180

parent 7258d337

CHANGES

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@@ -4,6 +4,11 @@ 


 Changes between 0.9.8p and 0.9.8q [xx XXX xxxx]



  *) Disable code workaround for ancient and obsolete Netscape browsers

     and servers: an attacker can use it in a ciphersuite downgrade attack.

     Thanks to Martin Rex for discovering this bug. CVE-2010-4180

     [Steve Henson]



  *) Fixed J-PAKE implementation error, originally discovered by

     Sebastien Martini, further info and confirmation from Stefan

     Arentz and Feng Hao. Note that this fix is a security fix. CVE-2010-4252

NEWS

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@@ -7,6 +7,7 @@ 


  Major changes between OpenSSL 0.9.8p and OpenSSL 0.9.8q:



      o Fix for security issue CVE-2010-4180

      o Fix for CVE-2010-4252



  Major changes between OpenSSL 0.9.8o and OpenSSL 0.9.8p:

doc/ssl/SSL_CTX_set_options.pod

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@@ -78,18 +78,7 @@ this breaks this server so 16 bytes is the way to go. 


=item SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG



ssl3.netscape.com:443, first a connection is established with RC4-MD5.

If it is then resumed, we end up using DES-CBC3-SHA.  It should be

RC4-MD5 according to 7.6.1.3, 'cipher_suite'.



Netscape-Enterprise/2.01 (https://merchant.netscape.com) has this bug.

It only really shows up when connecting via SSLv2/v3 then reconnecting

via SSLv3. The cipher list changes....



NEW INFORMATION.  Try connecting with a cipher list of just

DES-CBC-SHA:RC4-MD5.  For some weird reason, each new connection uses

RC4-MD5, but a re-connect tries to use DES-CBC-SHA.  So netscape, when

doing a re-connect, always takes the first cipher in the cipher list.

As of OpenSSL 0.9.8q and 1.0.0c, this option has no effect.



=item SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG

ssl/s3_clnt.c

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@@ -814,8 +814,11 @@ int ssl3_get_server_hello(SSL *s) 
		s->session->cipher_id = s->session->cipher->id;

	if (s->hit && (s->session->cipher_id != c->id))

		{

/* Workaround is now obsolete */

#if 0

		if (!(s->options &

			SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG))

#endif

			{

			al=SSL_AD_ILLEGAL_PARAMETER;

			SSLerr(SSL_F_SSL3_GET_SERVER_HELLO,SSL_R_OLD_SESSION_CIPHER_NOT_RETURNED);

ssl/s3_srvr.c

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@@ -927,6 +927,10 @@ int ssl3_get_client_hello(SSL *s) 
				break;

				}

			}

/* Disabled because it can be used in a ciphersuite downgrade

 * attack: CVE-2010-4180.

 */

#if 0

		if (j == 0 && (s->options & SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG) && (sk_SSL_CIPHER_num(ciphers) == 1))

			{

			/* Special case as client bug workaround: the previously used cipher may
@@ -941,6 +945,7 @@ int ssl3_get_client_hello(SSL *s) 
				j = 1;

				}

			}

#endif

		if (j == 0)

			{

			/* we need to have the cipher in the cipher