From 5d8aade01dd4a3dbbda1a39bbca0d755987d8d7c Mon Sep 17 00:00:00 2001
From: Andres Amaya Garcia <andres.amayagarcia@arm.com>
Date: Tue, 30 Oct 2018 18:21:41 +0000
Subject: [PATCH] Reduce priority of 3DES ciphersuites
---
ChangeLog | 5 ++++
include/mbedtls/config.h | 13 +++++++++
library/ssl_ciphersuites.c | 57 +++++++++++++++++++++++---------------
library/version_features.c | 3 ++
scripts/config.pl | 2 ++
5 files changed, 58 insertions(+), 22 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 311a51a55..3b1ab53dc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,10 @@ mbed TLS ChangeLog (Sorted per branch, date)
= mbed TLS 2.x.x branch released xxxx-xx-xx
+Features
+ * Add MBEDTLS_REMOVE_3DES_CIPHERSUITES to allow removing 3DES ciphersuites
+ from the default list (inactive by default).
+
Bugfix
* Fix a compilation issue with mbedtls_ecp_restart_ctx not being defined
when MBEDTLS_ECP_ALT is defined. Reported by jwhui. Fixes #2242.
@@ -37,6 +41,7 @@ Changes
* Ensure that ssl-opt.h can be run in OS X. #2029
* Reduce the complexity of the timing tests. They were assuming more than the
underlying OS actually guarantees.
+ * Ciphersuites based on 3DES now have the lowest priority by default.
= mbed TLS 2.16.0 branch released 2018-12-21
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 91cc5bddf..0505e8993 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -686,6 +686,19 @@
*/
#define MBEDTLS_REMOVE_ARC4_CIPHERSUITES
+/**
+ * \def MBEDTLS_REMOVE_3DES_CIPHERSUITES
+ *
+ * Remove 3DES ciphersuites by default in SSL / TLS.
+ * This flag removes the ciphersuites based on 3DES from the default list as
+ * returned by mbedtls_ssl_list_ciphersuites(). However, it is still possible
+ * to enable (some of) them with mbedtls_ssl_conf_ciphersuites() by including
+ * them explicitly.
+ *
+ * Comment this macro to keep 3DES in the default ciphersuite list.
+ */
+#define MBEDTLS_REMOVE_3DES_CIPHERSUITES
+
/**
* \def MBEDTLS_ECP_DP_SECP192R1_ENABLED
*
diff --git a/library/ssl_ciphersuites.c b/library/ssl_ciphersuites.c
index 745474eff..518f7dde0 100644
--- a/library/ssl_ciphersuites.c
+++ b/library/ssl_ciphersuites.c
@@ -43,11 +43,11 @@
/*
* Ordered from most preferred to least preferred in terms of security.
*
- * Current rule (except rc4, weak and null which come last):
+ * Current rule (except RC4 and 3DES, weak and null which come last):
* 1. By key exchange:
* Forward-secure non-PSK > forward-secure PSK > ECJPAKE > other non-PSK > other PSK
* 2. By key length and cipher:
- * ChaCha > AES-256 > Camellia-256 > ARIA-256 > AES-128 > Camellia-128 > ARIA-128 > 3DES
+ * ChaCha > AES-256 > Camellia-256 > ARIA-256 > AES-128 > Camellia-128 > ARIA-128
* 3. By cipher mode when relevant GCM > CCM > CBC > CCM_8
* 4. By hash function used when relevant
* 5. By key exchange/auth again: EC > non-EC
@@ -126,11 +126,6 @@ static const int ciphersuite_preference[] =
MBEDTLS_TLS_ECDHE_RSA_WITH_ARIA_128_CBC_SHA256,
MBEDTLS_TLS_DHE_RSA_WITH_ARIA_128_CBC_SHA256,
- /* All remaining >= 128-bit ephemeral suites */
- MBEDTLS_TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA,
- MBEDTLS_TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
- MBEDTLS_TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA,
-
/* The PSK ephemeral suites */
MBEDTLS_TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256,
MBEDTLS_TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256,
@@ -162,9 +157,6 @@ static const int ciphersuite_preference[] =
MBEDTLS_TLS_ECDHE_PSK_WITH_ARIA_128_CBC_SHA256,
MBEDTLS_TLS_DHE_PSK_WITH_ARIA_128_CBC_SHA256,
- MBEDTLS_TLS_ECDHE_PSK_WITH_3DES_EDE_CBC_SHA,
- MBEDTLS_TLS_DHE_PSK_WITH_3DES_EDE_CBC_SHA,
-
/* The ECJPAKE suite */
MBEDTLS_TLS_ECJPAKE_WITH_AES_128_CCM_8,
@@ -228,11 +220,6 @@ static const int ciphersuite_preference[] =
MBEDTLS_TLS_ECDH_RSA_WITH_ARIA_128_CBC_SHA256,
MBEDTLS_TLS_RSA_WITH_ARIA_128_CBC_SHA256,
- /* All remaining >= 128-bit suites */
- MBEDTLS_TLS_RSA_WITH_3DES_EDE_CBC_SHA,
- MBEDTLS_TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA,
- MBEDTLS_TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA,
-
/* The RSA PSK suites */
MBEDTLS_TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256,
MBEDTLS_TLS_RSA_PSK_WITH_AES_256_GCM_SHA384,
@@ -251,8 +238,6 @@ static const int ciphersuite_preference[] =
MBEDTLS_TLS_RSA_PSK_WITH_ARIA_128_GCM_SHA256,
MBEDTLS_TLS_RSA_PSK_WITH_ARIA_128_CBC_SHA256,
- MBEDTLS_TLS_RSA_PSK_WITH_3DES_EDE_CBC_SHA,
-
/* The PSK suites */
MBEDTLS_TLS_PSK_WITH_CHACHA20_POLY1305_SHA256,
MBEDTLS_TLS_PSK_WITH_AES_256_GCM_SHA384,
@@ -275,6 +260,16 @@ static const int ciphersuite_preference[] =
MBEDTLS_TLS_PSK_WITH_ARIA_128_GCM_SHA256,
MBEDTLS_TLS_PSK_WITH_ARIA_128_CBC_SHA256,
+ /* 3DES suites */
+ MBEDTLS_TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA,
+ MBEDTLS_TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
+ MBEDTLS_TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA,
+ MBEDTLS_TLS_ECDHE_PSK_WITH_3DES_EDE_CBC_SHA,
+ MBEDTLS_TLS_DHE_PSK_WITH_3DES_EDE_CBC_SHA,
+ MBEDTLS_TLS_RSA_WITH_3DES_EDE_CBC_SHA,
+ MBEDTLS_TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA,
+ MBEDTLS_TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA,
+ MBEDTLS_TLS_RSA_PSK_WITH_3DES_EDE_CBC_SHA,
MBEDTLS_TLS_PSK_WITH_3DES_EDE_CBC_SHA,
/* RC4 suites */
@@ -2187,6 +2182,26 @@ const int *mbedtls_ssl_list_ciphersuites( void )
static int supported_ciphersuites[MAX_CIPHERSUITES];
static int supported_init = 0;
+static int ciphersuite_is_removed( const mbedtls_ssl_ciphersuite_t *cs_info )
+{
+ (void)cs_info;
+
+#if defined(MBEDTLS_REMOVE_ARC4_CIPHERSUITES)
+ if( cs_info->cipher == MBEDTLS_CIPHER_ARC4_128 )
+ return( 1 );
+#endif /* MBEDTLS_REMOVE_ARC4_CIPHERSUITES */
+
+#if defined(MBEDTLS_REMOVE_3DES_CIPHERSUITES)
+ if( cs_info->cipher == MBEDTLS_CIPHER_DES_EDE3_ECB ||
+ cs_info->cipher == MBEDTLS_CIPHER_DES_EDE3_CBC )
+ {
+ return( 1 );
+ }
+#endif /* MBEDTLS_REMOVE_3DES_CIPHERSUITES */
+
+ return( 0 );
+}
+
const int *mbedtls_ssl_list_ciphersuites( void )
{
/*
@@ -2202,14 +2217,12 @@ const int *mbedtls_ssl_list_ciphersuites( void )
*p != 0 && q < supported_ciphersuites + MAX_CIPHERSUITES - 1;
p++ )
{
-#if defined(MBEDTLS_REMOVE_ARC4_CIPHERSUITES)
const mbedtls_ssl_ciphersuite_t *cs_info;
if( ( cs_info = mbedtls_ssl_ciphersuite_from_id( *p ) ) != NULL &&
- cs_info->cipher != MBEDTLS_CIPHER_ARC4_128 )
-#else
- if( mbedtls_ssl_ciphersuite_from_id( *p ) != NULL )
-#endif
+ !ciphersuite_is_removed( cs_info ) )
+ {
*(q++) = *p;
+ }
}
*q = 0;
diff --git a/library/version_features.c b/library/version_features.c
index 4c36d3caa..24143d052 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -300,6 +300,9 @@ static const char *features[] = {
#if defined(MBEDTLS_REMOVE_ARC4_CIPHERSUITES)
"MBEDTLS_REMOVE_ARC4_CIPHERSUITES",
#endif /* MBEDTLS_REMOVE_ARC4_CIPHERSUITES */
+#if defined(MBEDTLS_REMOVE_3DES_CIPHERSUITES)
+ "MBEDTLS_REMOVE_3DES_CIPHERSUITES",
+#endif /* MBEDTLS_REMOVE_3DES_CIPHERSUITES */
#if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
"MBEDTLS_ECP_DP_SECP192R1_ENABLED",
#endif /* MBEDTLS_ECP_DP_SECP192R1_ENABLED */
diff --git a/scripts/config.pl b/scripts/config.pl
index 3d2884cc9..42ec6f81b 100755
--- a/scripts/config.pl
+++ b/scripts/config.pl
@@ -29,6 +29,7 @@
# MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES
# MBEDTLS_NO_PLATFORM_ENTROPY
# MBEDTLS_REMOVE_ARC4_CIPHERSUITES
+# MBEDTLS_REMOVE_3DES_CIPHERSUITES
# MBEDTLS_SSL_HW_RECORD_ACCEL
# MBEDTLS_RSA_NO_CRT
# MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3
@@ -89,6 +90,7 @@ MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES
MBEDTLS_NO_PLATFORM_ENTROPY
MBEDTLS_RSA_NO_CRT
MBEDTLS_REMOVE_ARC4_CIPHERSUITES
+MBEDTLS_REMOVE_3DES_CIPHERSUITES
MBEDTLS_SSL_HW_RECORD_ACCEL
MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3
MBEDTLS_X509_ALLOW_UNSUPPORTED_CRITICAL_EXTENSION