add validation of compact binary payloads before reading them (#483)

* add validation of compact binary payloads before reading them

3 files changed, 47 insertions, 5 deletions

diff --git a/src/zencore/compactbinaryfile.cpp b/src/zencore/compactbinaryfile.cpp
index 1526c21d5..ec2fc3cd5 100644
--- a/src/zencore/compactbinaryfile.cpp
+++ b/src/zencore/compactbinaryfile.cpp
@@ -1,7 +1,7 @@
 // Copyright Epic Games, Inc. All Rights Reserved.
 
 #include "zencore/compactbinaryfile.h"
-#include "zencore/compactbinaryvalidation.h"
+#include "zencore/compactbinaryutil.h"
 
 #include <zencore/filesystem.h>
 
@@ -19,12 +19,12 @@ LoadCompactBinaryObject(const std::filesystem::path& FilePath)
 
 	IoBuffer ObjectBuffer = ObjectFile.Flatten();
 
-	if (CbValidateError Result = ValidateCompactBinary(ObjectBuffer, CbValidateMode::Default); Result == CbValidateError::None)
+	CbValidateError ValidateResult;
+	CbObject		Object = ValidateAndReadCompactBinaryObject(IoBuffer(ObjectBuffer), ValidateResult);
+	if (ValidateResult == CbValidateError::None)
 	{
-		CbObject	 Object	  = LoadCompactBinaryObject(ObjectBuffer);
 		const IoHash WorkerId = IoHash::HashBuffer(ObjectBuffer);
-
-		return {.Object = Object, .Hash = WorkerId};
+		return {.Object = std::move(Object), .Hash = WorkerId};
 	}
 
 	return {.Hash = IoHash::Zero};
diff --git a/src/zencore/compactbinaryutil.cpp b/src/zencore/compactbinaryutil.cpp
new file mode 100644
index 000000000..c8cde21c3
--- /dev/null
+++ b/src/zencore/compactbinaryutil.cpp
@@ -0,0 +1,33 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zencore/compactbinaryutil.h>
+
+#include <zencore/compress.h>
+#include <zencore/filesystem.h>
+
+namespace zen {
+
+CbObject
+ValidateAndReadCompactBinaryObject(const SharedBuffer&& Payload, CbValidateError& OutError)
+{
+	if (Payload.GetSize() > 0)
+	{
+		if (OutError = ValidateCompactBinary(Payload.GetView(), CbValidateMode::Default); OutError == CbValidateError::None)
+		{
+			return CbObject(std::move(Payload));
+		}
+	}
+	return CbObject();
+}
+
+CbObject
+ValidateAndReadCompactBinaryObject(const CompressedBuffer&& Payload, CbValidateError& OutError)
+{
+	if (CompositeBuffer Decompressed = Payload.DecompressToComposite())
+	{
+		return ValidateAndReadCompactBinaryObject(std::move(Decompressed).Flatten(), OutError);
+	}
+	return CbObject();
+}
+
+}  // namespace zen
diff --git a/src/zencore/include/zencore/compactbinaryutil.h b/src/zencore/include/zencore/compactbinaryutil.h
index 9524d1fc4..d750c6492 100644
--- a/src/zencore/include/zencore/compactbinaryutil.h
+++ b/src/zencore/include/zencore/compactbinaryutil.h
@@ -6,6 +6,7 @@
 
 #include <zencore/compactbinary.h>
 #include <zencore/compactbinarybuilder.h>
+#include <zencore/compactbinaryvalidation.h>
 
 namespace zen {
 
@@ -43,4 +44,12 @@ RewriteCbObject(CbObjectView InObj, Invocable<CbObjectWriter&, CbFieldView&> aut
 	return Writer.Save();
 }
 
+CbObject ValidateAndReadCompactBinaryObject(const SharedBuffer&& Payload, CbValidateError& OutError);
+inline CbObject
+ValidateAndReadCompactBinaryObject(const IoBuffer&& Payload, CbValidateError& OutError)
+{
+	return ValidateAndReadCompactBinaryObject(SharedBuffer(std::move(Payload)), OutError);
+}
+CbObject ValidateAndReadCompactBinaryObject(const CompressedBuffer&& Payload, CbValidateError& OutError);
+
 }  // namespace zen