From 502d8ed729502a73ebf93ad0937100df6577f417 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc=20B=C3=A4rtschi?=
 <19628374+m-baertschi@users.noreply.github.com>
Date: Wed, 18 Sep 2024 14:11:22 +0200
Subject: [PATCH] fix wrong buffer conversion for Uint8Array (#8787)

If the BufferSource is already an Uint8Array which is a view of a subset of the underlying ArrayBuffer then accessing .buffer caused the whole backing buffer to be returned. Fix this by just returning the original Uint8Array as-is.

Co-authored-by: Justin Baur <19896123+justindbaur@users.noreply.github.com>
---
 libs/common/src/platform/services/fido2/fido2-utils.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libs/common/src/platform/services/fido2/fido2-utils.ts b/libs/common/src/platform/services/fido2/fido2-utils.ts
index 13c9762135..c3c3eba246 100644
--- a/libs/common/src/platform/services/fido2/fido2-utils.ts
+++ b/libs/common/src/platform/services/fido2/fido2-utils.ts
@@ -17,8 +17,10 @@ export class Fido2Utils {
     return Fido2Utils.fromB64ToArray(Fido2Utils.fromUrlB64ToB64(str));
   }
 
-  static bufferSourceToUint8Array(bufferSource: BufferSource) {
-    if (Fido2Utils.isArrayBuffer(bufferSource)) {
+  static bufferSourceToUint8Array(bufferSource: BufferSource): Uint8Array {
+    if (bufferSource instanceof Uint8Array) {
+      return bufferSource;
+    } else if (Fido2Utils.isArrayBuffer(bufferSource)) {
       return new Uint8Array(bufferSource);
     } else {
       return new Uint8Array(bufferSource.buffer);