From ae3e9adc1bb19ed4db9ea4bf95bb436df91f687b Mon Sep 17 00:00:00 2001
From: James Price <jrprice@google.com>
Date: Mon, 27 Feb 2023 21:21:02 +0000
Subject: [PATCH] dawn/node: Fix array buffer view conversion

A Napi::TypedArray may have a non-zero offset on its underlying
ArrayBuffer backing buffer. Also use the length of the typed array,
not the backing buffer.

Change-Id: Icaa310ef8f87393b4d7582ba0a0afb2b87318664
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/121820
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: James Price <jrprice@google.com>
---
 src/dawn/node/binding/Converter.cpp | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/dawn/node/binding/Converter.cpp b/src/dawn/node/binding/Converter.cpp
index e645c44dc1..94c91d62e8 100644
--- a/src/dawn/node/binding/Converter.cpp
+++ b/src/dawn/node/binding/Converter.cpp
@@ -153,15 +153,20 @@ bool Converter::Convert(wgpu::ImageCopyBuffer& out, const interop::GPUImageCopyB
 bool Converter::Convert(BufferSource& out, interop::BufferSource in) {
     out = {};
     if (auto* view = std::get_if<interop::ArrayBufferView>(&in)) {
-        std::visit(
+        return std::visit(
             [&](auto&& v) {
                 auto arr = v.ArrayBuffer();
-                out.data = arr.Data();
-                out.size = arr.ByteLength();
+                if (v.ByteOffset() + v.ByteLength() > arr.ByteLength()) {
+                    Napi::Error::New(env, "offset + length exceeds underlying buffer size")
+                        .ThrowAsJavaScriptException();
+                    return false;
+                }
+                out.data = static_cast<uint8_t*>(arr.Data()) + v.ByteOffset();
+                out.size = v.ByteLength();
                 out.bytesPerElement = v.ElementSize();
+                return true;
             },
             *view);
-        return true;
     }
     if (auto* arr = std::get_if<interop::ArrayBuffer>(&in)) {
         out.data = arr->Data();