In the interests of being secure by default, make the default TLS ciphers

be those that are TLSv1.2 with AEAD and PFS. Provide a "compat" mode that
allows the previous default ciphers to be selected.

Discussed with tedu@ during s2k15.

2 files changed, 17 insertions, 2 deletions

diff --git a/src/lib/libtls/tls_config.c b/src/lib/libtls/tls_config.c
index bec7afcb1b..80242861c7 100644
--- a/src/lib/libtls/tls_config.c
+++ b/src/lib/libtls/tls_config.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_config.c,v 1.6 2015/02/12 04:35:17 jsing Exp $ */
+/* $OpenBSD: tls_config.c,v 1.7 2015/02/22 14:50:41 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -74,6 +74,10 @@ tls_config_new(void)
         }
         tls_config_set_dheparams(config, "none");
         tls_config_set_ecdhecurve(config, "auto");
+        if (tls_config_set_ciphers(config, "secure") != 0) {
+                tls_config_free(config);
+                return (NULL);
+        }
         tls_config_set_protocols(config, TLS_PROTOCOLS_DEFAULT);
         tls_config_set_verify_depth(config, 6);
         
@@ -201,6 +205,14 @@ tls_config_set_cert_mem(struct tls_config *config, const uint8_t *cert,
 int
 tls_config_set_ciphers(struct tls_config *config, const char *ciphers)
 {
+        if (ciphers == NULL ||
+            strcasecmp(ciphers, "default") == 0 ||
+            strcasecmp(ciphers, "secure") == 0)
+                ciphers = TLS_CIPHERS_DEFAULT;
+        else if (strcasecmp(ciphers, "compat") == 0 ||
+            strcasecmp(ciphers, "legacy") == 0)
+                ciphers = TLS_CIPHERS_COMPAT;
+
         return set_string(&config->ciphers, ciphers);
 }
 
diff --git a/src/lib/libtls/tls_internal.h b/src/lib/libtls/tls_internal.h
index 78e6b1fe2b..d1ba48ea1a 100644
--- a/src/lib/libtls/tls_internal.h
+++ b/src/lib/libtls/tls_internal.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_internal.h,v 1.10 2015/02/11 06:46:33 jsing Exp $ */
+/* $OpenBSD: tls_internal.h,v 1.11 2015/02/22 14:50:41 jsing Exp $ */
 /*
  * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
@@ -25,6 +25,9 @@
 
 #define _PATH_SSL_CA_FILE "/etc/ssl/cert.pem"
 
+#define TLS_CIPHERS_COMPAT      "ALL:!aNULL:!eNULL"
+#define TLS_CIPHERS_DEFAULT     "TLSv1.2+AEAD+ECDHE:TLSv1.2+AEAD+DHE"
+
 struct tls_config {
         const char *ca_file;
         const char *ca_path;