[glib-networking] gnutls: Provide better error message when TLS alert is received

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 0160a89e195d25635596198e82691d29375f3c87
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Tue May 16 23:16:20 2017 -0500

    gnutls: Provide better error message when TLS alert is received
    
    Print a message describing the alert.
    
    This also changes the error code used when a TLS alert is received from
    G_TLS_ERROR_NOT_TLS, which is clearly inappropriate as the peer must
    support TLS if it is sending a TLS alert, to G_TLS_ERROR_MISC.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=782218

 tls/gnutls/gtlsconnection-gnutls.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)
---
diff --git a/tls/gnutls/gtlsconnection-gnutls.c b/tls/gnutls/gtlsconnection-gnutls.c
index 05e38b6..d2914fa 100644
--- a/tls/gnutls/gtlsconnection-gnutls.c
+++ b/tls/gnutls/gtlsconnection-gnutls.c
@@ -784,7 +784,6 @@ end_gnutls_io (GTlsConnectionGnutls  *gnutls,
       if (g_error_matches (my_error, G_IO_ERROR, G_IO_ERROR_FAILED) ||
          g_error_matches (my_error, G_IO_ERROR, G_IO_ERROR_BROKEN_PIPE) ||
          status == GNUTLS_E_UNEXPECTED_PACKET_LENGTH ||
-         status == GNUTLS_E_FATAL_ALERT_RECEIVED ||
          status == GNUTLS_E_DECRYPTION_FAILED ||
          status == GNUTLS_E_UNSUPPORTED_VERSION_PACKET)
        {
@@ -848,6 +847,13 @@ end_gnutls_io (GTlsConnectionGnutls  *gnutls,
                            _("TLS connection peer did not send a certificate"));
       return status;
     }
+  else if (status == GNUTLS_E_FATAL_ALERT_RECEIVED)
+    {
+      g_set_error (error, G_TLS_ERROR, G_TLS_ERROR_MISC,
+                  _("Peer sent fatal TLS alert: %s"),
+                  gnutls_alert_get_name (gnutls_alert_get (gnutls->priv->session)));
+      return status;
+    }
 
   if (error)
     {