From f474ec2a887f2ef1dba536683f5a7c8b6dc7e283 Mon Sep 17 00:00:00 2001 From: Dan Winship Date: Thu, 13 Nov 2014 22:30:13 -0500 Subject: [PATCH 2/2] gnutls: update default priority string and fallback rules Change the default "priority" string from "NORMAL:%COMPAT" to "NORMAL:%COMPAT:%LATEST_RECORD_VERSION". (Correctly-implemented servers won't care either way, but apparently some servers have been incorrectly updated for POODLE-safeness by rejecting all handshakes with SSL 3.0 in the version field [which had long been recommended for compatibility reasons], even if the handshake offered to negotiate TLS versions too.) Change the fallback/"ssl3" priority code so that it never includes %LATEST_RECORD_VERSION, but does include %COMPAT even if the default priority doesn't (eg, because it was overridden with G_TLS_GNUTLS_PRIORITY). https://bugzilla.gnome.org/show_bug.cgi?id=740087 --- tls/gnutls/gtlsconnection-gnutls.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/tls/gnutls/gtlsconnection-gnutls.c b/tls/gnutls/gtlsconnection-gnutls.c index 444ca36..7436451 100644 --- a/tls/gnutls/gtlsconnection-gnutls.c +++ b/tls/gnutls/gtlsconnection-gnutls.c @@ -197,6 +197,8 @@ g_tls_connection_gnutls_init (GTlsConnectionGnutls *gnutls) /* First field is "fallback", second is "allow unsafe rehandshaking" */ static gnutls_priority_t priorities[2][2]; +#define DEFAULT_BASE_PRIORITY "NORMAL:%COMPAT:%LATEST_RECORD_VERSION" + static void g_tls_connection_gnutls_init_priorities (void) { @@ -207,12 +209,12 @@ g_tls_connection_gnutls_init_priorities (void) base_priority = g_getenv ("G_TLS_GNUTLS_PRIORITY"); if (!base_priority) - base_priority = "NORMAL:%COMPAT"; + base_priority = DEFAULT_BASE_PRIORITY; ret = gnutls_priority_init (&priorities[FALSE][FALSE], base_priority, NULL); if (ret == GNUTLS_E_INVALID_REQUEST) { g_warning ("G_TLS_GNUTLS_PRIORITY is invalid; ignoring!"); - base_priority = "NORMAL:%COMPAT"; + base_priority = DEFAULT_BASE_PRIORITY; gnutls_priority_init (&priorities[FALSE][FALSE], base_priority, NULL); } @@ -236,8 +238,21 @@ g_tls_connection_gnutls_init_priorities (void) } else { - fallback_priority = g_strdup_printf ("%s:!VERS-TLS-ALL:+VERS-%s", - base_priority, + gchar *cleaned_base, *p, *rest; + + /* fallback_priority should be based on base_priority, except + * that we don't want %LATEST_RECORD_VERSION in it. + */ + cleaned_base = g_strdup (base_priority); + p = strstr (cleaned_base, ":%LATEST_RECORD_VERSION"); + if (p) + { + rest = p + strlen (":%LATEST_RECORD_VERSION"); + memmove (p, rest, strlen (rest) + 1); + } + + fallback_priority = g_strdup_printf ("%s:%%COMPAT:!VERS-TLS-ALL:+VERS-%s", + cleaned_base, gnutls_protocol_get_name (fallback_proto)); } fallback_unsafe_rehandshake_priority = g_strdup_printf ("%s:%%UNSAFE_RENEGOTIATION", -- 2.1.0