From eaf465d0df2ba0d03bea97a7b5e2d9f65afca2ca Mon Sep 17 00:00:00 2001
From: SheetJS <dev@sheetjs.com>
Date: Fri, 27 Jan 2023 01:36:57 -0800
Subject: [PATCH] Blob#slice end <= size (fixes #35959) (#35971)

Summary:
See https://github.com/facebook/react-native/issues/35959 .  Potentially fixes other issues including https://github.com/facebook/react-native/issues/34988

## Changelog

[INTERNAL] [FIXED] - Blob#slice end check avoids overflow

Pull Request resolved: https://github.com/facebook/react-native/pull/35971

Test Plan: Added a test which fails against current release but passes after code changes.

Reviewed By: cipolleschi

Differential Revision: D42772352

Pulled By: jacdebug

fbshipit-source-id: 3c26baedad5cd459061459a9485ae20af1d2417b
---
 Libraries/Blob/Blob.js                | 4 ++++
 Libraries/Blob/__tests__/Blob-test.js | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/Libraries/Blob/Blob.js b/Libraries/Blob/Blob.js
index 862c3f50bdcb0f..a75fb1b3688a16 100644
--- a/Libraries/Blob/Blob.js
+++ b/Libraries/Blob/Blob.js
@@ -98,6 +98,10 @@ class Blob {
           // $FlowFixMe[reassign-const]
           end = this.size + end;
         }
+        if (end > this.size) {
+          // $FlowFixMe[reassign-const]
+          end = this.size;
+        }
         size = end - start;
       }
     }
diff --git a/Libraries/Blob/__tests__/Blob-test.js b/Libraries/Blob/__tests__/Blob-test.js
index 9fdabab67ef530..e5308c0d2c5811 100644
--- a/Libraries/Blob/__tests__/Blob-test.js
+++ b/Libraries/Blob/__tests__/Blob-test.js
@@ -71,6 +71,11 @@ describe('Blob', function () {
     expect(sliceB.data.offset).toBe(2384);
     expect(sliceB.size).toBe(7621 - 2384);
     expect(sliceB.type).toBe('');
+
+    const sliceC = blob.slice(34543, 34569);
+
+    expect(sliceC.data.offset).toBe(34543);
+    expect(sliceC.size).toBe(Math.min(blob.data.size, 34569) - 34543);
   });
 
   it('should close a blob', () => {