CVE-2010-4180 fix (from OpenSSL_1_0_0-stable)

CHANGES

@@ -175,6 +175,11 @@
 
  Changes between 1.0.0b and 1.0.0c  [2 Dec 2010]
 
+  *) 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

@@ -5,6 +5,14 @@
   This file gives a brief overview of the major changes between each OpenSSL
   release. For more details please read the CHANGES file.
 
+  Major changes between OpenSSL 1.0.0b and OpenSSL 1.0.0c:
+
+      o Fix for security issue CVE-2010-4180
+      o Fix for CVE-2010-4252
+      o Fix mishandling of absent EC point format extension.
+      o Fix various platform compilation issues.
+      o Corrected fix for security issue CVE-2010-3864.
+
   Major changes between OpenSSL 1.0.0a and OpenSSL 1.0.0b:
 
       o Fix for security issue CVE-2010-3864.

doc/ssl/SSL_CTX_set_options.pod

@@ -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

@@ -884,8 +884,11 @@ 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

@@ -1019,6 +1019,10 @@ 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
@@ -1033,6 +1037,7 @@ int ssl3_get_client_hello(SSL *s)
 				j = 1;
 				}
 			}
+#endif
 		if (j == 0)
 			{
 			/* we need to have the cipher in the cipher