[glib-networking] Avoid trailing dots in SNI hostnames

[Michael Catanzaro <mcatanzaro src gnome org>]

commit f8703406a623d7bfcf27cc466386dc6532532285
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Wed Aug 8 12:55:15 2018 -0500

    Avoid trailing dots in SNI hostnames
    
    Sending the trailing dot violates RFC 6066 section 3: "The hostname is
    represented as a byte string using ASCII encoding without a trailing
    dot." gnutls_server_name_set() should probably strip the trailing dot
    for us, but man page says we are responsible for doing so manually... so
    do it.
    
    Hopefully fixes #11

 tls/gnutls/gtlsclientconnection-gnutls.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
---
diff --git a/tls/gnutls/gtlsclientconnection-gnutls.c b/tls/gnutls/gtlsclientconnection-gnutls.c
index af8e823..cac2deb 100644
--- a/tls/gnutls/gtlsclientconnection-gnutls.c
+++ b/tls/gnutls/gtlsclientconnection-gnutls.c
@@ -213,8 +213,15 @@ g_tls_client_connection_gnutls_initable_init (GInitable       *initable,
   hostname = get_server_identity (G_TLS_CLIENT_CONNECTION_GNUTLS (gnutls));
   if (hostname)
     {
+      gchar *normalized_hostname = g_strdup (hostname);
+
+      if (hostname[strlen (hostname) - 1] == '.')
+        normalized_hostname[strlen (hostname) - 1] = '\0';
+
       gnutls_server_name_set (session, GNUTLS_NAME_DNS,
-                              hostname, strlen (hostname));
+                              normalized_hostname, strlen (normalized_hostname));
+
+      g_free (normalized_hostname);
     }
 
   return TRUE;