fix for CVE-2010-4180

diff --git a/CHANGES b/CHANGES
index 00067bf14c6d878ab42ea1e712188876e5ee2087..365201d22aeca7e911d3e3540919f180f2123959 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -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

diff --git a/NEWS b/NEWS
index 34b27af76cd90d4cee0a01e9298a2740996d9fbd..df190f815e66095e2443cbb48c9e913fc2f35b3a 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -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:

diff --git a/doc/ssl/SSL_CTX_set_options.pod b/doc/ssl/SSL_CTX_set_options.pod
index 06025d13fafb0ffda9abd8eecaf3c53d4b4387fd..a703ce0b8860e860b5565a3346e20227c42df46a 100644 (file)
--- a/doc/ssl/SSL_CTX_set_options.pod
+++ b/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
 

diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index f0995b96acea28bf7e40f6e23b983d7877bc9189..a7cb7a1ebf30761fb5435ee3ef9037d59540ea41 100644 (file)
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -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);

diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c
index e696450d6569a9593c226d5a694610fd81e91141..e2d570f80f0a373b846755a2c115cb96a7c8f98d 100644 (file)
--- a/ssl/s3_srvr.c
+++ b/ssl/s3_srvr.c
@@ -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