Fix behavior of NULL ccname for cookie creation

This resolves an issue where the session cookie would not be populated
when sesions were used but unique ccaches were not.

Based on a report from Bhagavan Das.

Signed-off-by: Robbie Harwood <rharwood@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Closes #98

Author: frozencemetery

src/sessions.c

@@ -236,8 +236,13 @@ void mag_attempt_session(struct mag_req_cfg *cfg, struct mag_conn *mc)
                              (const char *)mc->basic_hash.value,
                              mc->basic_hash.length) != 0)
         goto done;
-    if (OCTET_STRING_fromString(&gsessdata.ccname, mc->ccname) != 0)
+
+    /* NULL ccname here just means default ccache */
+    if (mc->ccname &&
+        OCTET_STRING_fromString(&gsessdata.ccname, mc->ccname) != 0) {
         goto done;
+    }
+
     ret = encode_GSSSessionData(req->pool, &gsessdata,
                                 &plainbuf.value, &plainbuf.length);
     if (ret == false) {