Improve logging on signature verification

If xmlsec and vgauth are built inconsistently, xmlSecSize
can differ between the two, which results in a key datastructure
being a different size, and vgauth ends up looking in the
wrong place in memory for the signature check status.

Log the status, so that if its not one of the two
expected values, we have some ideas of what went wrong.

diff --git a/open-vm-tools/vgauth/serviceImpl/saml-xmlsec1.c b/open-vm-tools/vgauth/serviceImpl/saml-xmlsec1.c
index 2906d293207963f790a4d7ea401fd84eb743a788..d5bb4f8b9e34bc694d0e72922587cbb7c8847049 100644 (file)
--- a/open-vm-tools/vgauth/serviceImpl/saml-xmlsec1.c
+++ b/open-vm-tools/vgauth/serviceImpl/saml-xmlsec1.c
@@ -1,5 +1,5 @@
 /*********************************************************
- * Copyright (C) 2016-2019 VMware, Inc. All rights reserved.
+ * Copyright (C) 2016-2020 VMware, Inc. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as published
@@ -1297,11 +1297,22 @@ VerifySignature(xmlDocPtr doc,
    /*
     * Check status to verify the signature is correct.
     *
+    * This check can fail due to build issues.  If xmlSecSize is
+    * different between this layer and the xmlsec library,
+    * dsigCtx->status can be at the wrong offset.  So
+    * dump the value of status, which should be either
+    * 1 (xmlSecDSigStatusSucceeded) or 2 (xmlSecDSigStatusInvalid).
+    * If its something else, that's a sign there's a
+    * build issue and XMLSEC_NO_SIZE_T may be set at one layer but
+    * not the other.
+    *
     */
    if (dsigCtx->status != xmlSecDSigStatusSucceeded) {
-      g_warning("Signature is INVALID\n");
+      g_warning("%s: Signature is invalid (got %d)\n",
+                __FUNCTION__, dsigCtx->status);
       VMXLog_Log(VMXLOG_LEVEL_WARNING,
-                 "%s: signature is invalid\n", __FUNCTION__);
+                 "%s: signature is invalid (got %d)\n", __FUNCTION__,
+                 dsigCtx->status);
       goto done;
    }