From 33feba63fc645f4db5e3c18a54203252c172314f Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Thu, 19 Jan 2012 20:07:44 +0100
Subject: [PATCH] OpenSSL: don't disable security work-around
OpenSSL added a work-around for a SSL 3.0/TLS 1.0 CBC vulnerability
(http://www.openssl.org/~bodo/tls-cbc.txt). In 0.9.6e they added a bit
to SSL_OP_ALL that _disables_ that work-around despite the fact that
SSL_OP_ALL is documented to do "rather harmless" workarounds.
The libcurl code uses the SSL_OP_ALL define and thus logically always
disables the OpenSSL fix.
In order to keep the secure work-around workding, the
SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS bit must not be set and this change
makes sure of this.
Reported by: product-security at Apple
---
lib/ssluse.c | 22 +++++++++++++++++-----
1 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/lib/ssluse.c b/lib/ssluse.c
index af70fe0..d9c0a8f 100644
--- lib/ssluse.c
+++ lib/ssluse.c
@@ -1422,6 +1422,7 @@ ossl_connect_step1(struct connectdata *conn,
X509_LOOKUP *lookup=NULL;
curl_socket_t sockfd = conn->sock[sockindex];
struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+ long ctx_options;
#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
bool sni;
#ifdef ENABLE_IPV6
@@ -1502,16 +1503,27 @@ ossl_connect_step1(struct connectdata *conn,
If someone writes an application with libcurl and openssl who wants to
enable the feature, one can do this in the SSL callback.
+ OpenSSL added a work-around for a SSL 3.0/TLS 1.0 CBC vulnerability
+ (http://www.openssl.org/~bodo/tls-cbc.txt). In 0.9.6e they added a bit to
+ SSL_OP_ALL that _disables_ that work-around despite the fact that
+ SSL_OP_ALL is documented to do "rather harmless" workarounds. In order to
+ keep the secure work-around, the SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS bit
+ must not be set.
+
*/
+
+ ctx_options = SSL_OP_ALL;
+
#ifdef SSL_OP_NO_TICKET
/* expect older openssl releases to not have this define so only use it if
present */
-#define CURL_CTX_OPTIONS SSL_OP_ALL|SSL_OP_NO_TICKET
-#else
-#define CURL_CTX_OPTIONS SSL_OP_ALL
+ ctx_options |= SSL_OP_NO_TICKET;
+#endif
+#ifdef SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
+ ctx_options &= ~SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS;
#endif
- SSL_CTX_set_options(connssl->ctx, CURL_CTX_OPTIONS);
+ SSL_CTX_set_options(connssl->ctx, ctx_options);
/* disable SSLv2 in the default case (i.e. allow SSLv3 and TLSv1) */
if(data->set.ssl.version == CURL_SSLVERSION_DEFAULT)
--
1.7.8.3