fix for CVE-2010-4180

diff --git a/CHANGES b/CHANGES
index 6c302f77875fdae5ecf29aafb3d036c979fd48b6..408255ddf63c0bb9977d75e92b17a3bce2feaa0e 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,11 @@
 
  Changes between 1.0.0b and 1.0.0c  [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 dc78b1bafcf9ea20b87130a6f2bf8ecb1988ff99..139c1e02b4509589005c9b5b8c9a404d57f78c04 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,7 @@
 
   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.

diff --git a/doc/ssl/SSL_CTX_set_options.pod b/doc/ssl/SSL_CTX_set_options.pod
index 310db84b31429dd036468f5f268de8ae653d787f..cc588f3a78f3a302a4b422bc2fdc9dc55728e5d9 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 6eab135c05689aefd10c0bfe751b6930bea535e5..c22837d05dc90fe3f15d66e7a128d581cfa46a3f 100644 (file)
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -866,8 +866,11 @@ 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 d0921c59fc38bdb52faaf62b2775da6334b753db..514f72c97fa6bc08a614846dbf7f791b314a23d5 100644 (file)
--- a/ssl/s3_srvr.c
+++ b/ssl/s3_srvr.c
@@ -985,6 +985,10 @@ 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
@@ -999,6 +1003,7 @@ int ssl3_get_client_hello(SSL *s)
                                j = 1;
                                }
                        }
+#endif
                if (j == 0)
                        {
                        /* we need to have the cipher in the cipher