{StaticResource} references are broken for XPS Paths after December2022 security patch

[ezolenko]

• Windows version: (22H2 19045.2364)
• Does the bug reproduce also in WPF for .NET Framework 4.8?: Yes

Problem description:

{StaticResource} references on Path elements are not loaded in FixedPage after recent security patch.

Actual behavior:

FixedPage fails to load Path elements that have static resource references. Path data is set to null so those elements are not rendered with RenderTargetBitmap for example.

Expected behavior:

Path references are loaded.

Minimal repro:

• Make sure December 13, 2022, security updates for .NET Framework is installed
• Load attached xps file: p1.zip

var filePath = "<path>";
var doc = new XpsDocument(filePath, FileAccess.Read);
var seq = doc.GetFixedDocumentSequence();

foreach (var docRef in seq.References)
{
	var fixedDoc = docRef.GetDocument(false);
	foreach (var page in fixedDoc.Pages)
	{
		var fixedPage = page.GetPageRoot(false);
		foreach (var element in fixedPage.Children)
		{
			Debug.Assert(((System.Windows.Shapes.Path)element).Data != null);
		}
	}
}

You can probably reproduce this by printing most PDF files with some text to Microsoft XPS Document Writer and then trying to present it in a WPF app (that is not Windows XPS Viewer).

Workaround:

Alternate Workaround from kb5022083 (allowing all XPS types) works. I haven't figured out which type needs to be specifically allowed for this particular case. The script they have in the first part to allow certain types explicitly doesn't work.

https://support.microsoft.com/en-au/topic/kb5022083-change-in-how-wpf-based-applications-render-xps-documents-a4ae4fa4-bc58-4c37-acdd-5eebc4e34556

[singhashish-wpf]

We are checking this further. Will update soon.

[wstaelens]

https://developercommunity.visualstudio.com/t/KB5022083---Broken-XPS-prinintg-in-WPF-A/10233950?q=xps

[bradleypeet]

We're seeing the same issue and have some very unhappy customers right now.

[pchaurasia14]

We're sorry that the update broke your application. Rest assured, we're working to the fix the issue at top priority.

[gejosdev]

This issue leaves us with lots of customers not just "unhappy" but unable to invoice their work! This is a really money burning problem!!

[pchaurasia14]

@gejosdev - I agree the situation is not ideal and we're doing everything we can to ensure we restore the functionality without resurrecting the vulnerability. For now, you may attempt to use the workaround mentioned in this KB article.

[wstaelens]

@gejosdev this one also: dotnet/runtime#51929, #3546
but still waiting, after years.... it is not fun to get to your customers/clients and to tell them Microsoft didn't fix it yet.... for something that worked in .NET Framework.

We just take this one also.... The fix takes ages, means the team is not really into XPS/Printing...
Wish i could redirect all my phone calls to the WPF team.

[Toemsel]

There is also a second issue with that one: When you merge XPS files with the following method, the final XpsDocument lacks resources. I did extract the .XPS file and investigated the *.fpage files and encountered, that the ResourceDictionary is missing for the FixedPage after using the method below.

        public void MergeXpsDocument(string newFile, List<XpsDocument> sourceDocuments)
        {
            XpsDocument xpsDocument = new XpsDocument(newFile, System.IO.FileAccess.ReadWrite);
            XpsDocumentWriter xpsDocumentWriter = XpsDocument.CreateXpsDocumentWriter(xpsDocument);
            FixedDocumentSequence fixedDocumentSequence = new FixedDocumentSequence();

            foreach (XpsDocument doc in sourceDocuments)
            {
                FixedDocumentSequence sourceSequence = doc.GetFixedDocumentSequence();
                foreach (DocumentReference dr in sourceSequence.References)
                {
                    DocumentReference newDocumentReference = new DocumentReference();
                    newDocumentReference.Source = dr.Source;
                    (newDocumentReference as IUriContext).BaseUri = (dr as IUriContext).BaseUri;
                    FixedDocument fd = newDocumentReference.GetDocument(true);
                    newDocumentReference.SetDocument(fd);
                    fixedDocumentSequence.References.Add(newDocumentReference);
                }
            }
            xpsDocumentWriter.Write(fixedDocumentSequence);
            xpsDocument.Close();
        }

[pchaurasia14]

We've released an OOB package that should address the XPS compatibility issues.
You may refer to this link for more information on installing the fix.