fix(cbor): incorrect decoding with subarrays (#6344)

denoland · Jan 15, 2025 · c73f668 · c73f668
1 parent 55b1c7e
commit c73f668
Show file tree

Hide file tree

Showing 2 changed files with 34 additions and 2 deletions.
diff --git a/cbor/_common_decode.ts b/cbor/_common_decode.ts
@@ -10,7 +10,7 @@ function calcLength(
   offset: number,
 ): [number | bigint, number] {
   if (aI < 24) return [aI, offset];
-  const view = new DataView(input.buffer);
+  const view = new DataView(input.buffer, input.byteOffset, input.byteLength);
   switch (aI) {
     case 24:
       return [view.getUint8(offset), offset + 1];
@@ -312,7 +312,7 @@ function decodeSeven(
     case 23:
       return [undefined, offset];
   }
-  const view = new DataView(input.buffer);
+  const view = new DataView(input.buffer, input.byteOffset, input.byteLength);
   switch (aI) {
     case 25:
       return [view.getFloat16(offset), offset + 2];

diff --git a/cbor/decode_cbor_test.ts b/cbor/decode_cbor_test.ts
@@ -814,3 +814,35 @@ Deno.test("decodeCbor() rejecting tagNumber 259 due to invalid indefinite length
     "More bytes were expected",
   );
 });
+
+Deno.test("decodeCbor() correctly decoding with subarrays", () => {
+  let encodedData = encodeCbor(0);
+  let buffer = new Uint8Array(encodedData.length + 7);
+  buffer.set(encodedData, 7);
+  assertEquals(decodeCbor(buffer.subarray(7)), 0);
+
+  encodedData = encodeCbor(24);
+  buffer = new Uint8Array(encodedData.length + 7);
+  buffer.set(encodedData, 7);
+  assertEquals(decodeCbor(buffer.subarray(7)), 24);
+
+  encodedData = encodeCbor(2 ** 8);
+  buffer = new Uint8Array(encodedData.length + 7);
+  buffer.set(encodedData, 7);
+  assertEquals(decodeCbor(buffer.subarray(7)), 2 ** 8);
+
+  encodedData = encodeCbor(2 ** 16);
+  buffer = new Uint8Array(encodedData.length + 7);
+  buffer.set(encodedData, 7);
+  assertEquals(decodeCbor(buffer.subarray(7)), 2 ** 16);
+
+  encodedData = encodeCbor(2 ** 32);
+  buffer = new Uint8Array(encodedData.length + 7);
+  buffer.set(encodedData, 7);
+  assertEquals(decodeCbor(buffer.subarray(7)), 2n ** 32n);
+
+  encodedData = encodeCbor(3.14);
+  buffer = new Uint8Array(encodedData.length + 7);
+  buffer.set(encodedData, 7);
+  assertEquals(decodeCbor(buffer.subarray(7)), 3.14);
+});