fix(pe): validate SignedData version INTEGER content (#10054)

fix(pe): validate SignedData version integer encoding

src/native/pe/PeCertificateAsn1.ts

@@ -230,11 +230,7 @@ const decodeDirectoryString = (
 // X.690 8.3.1 and 8.3.2 hold for BER as well as DER: an INTEGER has at least
 // one content octet, and its first nine bits are never all zeros or all ones.
 // Padded encodings would otherwise collapse onto the minimal serial's hex.
-const integerHex = (
-  content: Buffer,
-  budget: DecodedNameBudget,
-  label: string,
-): string => {
+const requireIntegerContent = (content: Buffer, label: string): void => {
   if (content.length === 0) return fail(`${label} INTEGER is empty.`);
   const second = content[1];
   if (
@@ -243,6 +239,14 @@ const integerHex = (
       (content[0] === 0xff && second >= 0x80))
   )
     return fail(`${label} INTEGER is not minimally encoded.`);
+};
+
+const integerHex = (
+  content: Buffer,
+  budget: DecodedNameBudget,
+  label: string,
+): string => {
+  requireIntegerContent(content, label);
   let start = 0;
   while (start < content.length - 1 && content[start] === 0) start += 1;
   chargeDecodedName(budget, (content.length - start) * 2);
@@ -716,6 +720,7 @@ const parseSignedData = (
   const [version, digestSet, encapContentInfo] = children;
   if (version === undefined || version.tag !== 0x02)
     return fail("SignedData is missing version.");
+  requireIntegerContent(version.content, "SignedData version");
   if (digestSet === undefined || digestSet.tag !== 0x31)
     return fail("SignedData is missing digestAlgorithms.");
   if (

src/native/pe/PeCertificateParser.test.ts

@@ -1274,3 +1274,49 @@ it("rejects malformed and repeated certificate extensions", () => {
     ).subject.text,
   ).toBe("commonName=Fixture");
 });
+
+it.each([[], [0x00, 0x01], [0xff, 0xff]].map((version) => ({ version })))(
+  "rejects malformed SignedData version INTEGER content $version",
+  ({ version }) => {
+    const original = pkcs7SignedDataFixture();
+    const signed = readAsn1(original).children[1]!.children[0]!;
+    const payload = contentInfo(
+      derSeq(
+        der(0x02, Buffer.from(version)),
+        ...signed.children
+          .slice(1)
+          .map((node) => original.subarray(node.start, node.end)),
+      ),
+    );
+    expect(() => parse(peCertificateFixture(false, payload))).toThrow(
+      /SignedData version INTEGER/u,
+    );
+  },
+);
+
+it.each([
+  { name: "short form", version: Buffer.from([0x02, 0x01, 0x01]) },
+  { name: "BER long form", version: Buffer.from([0x02, 0x81, 0x01, 0x01]) },
+])(
+  "retains a valid SignedData version with $name length encoding",
+  ({ version }) => {
+    const original = pkcs7SignedDataFixture();
+    const signed = readAsn1(original).children[1]!.children[0]!;
+    const payload = contentInfo(
+      derSeq(
+        version,
+        ...signed.children
+          .slice(1)
+          .map((node) => original.subarray(node.start, node.end)),
+      ),
+    );
+    const report = parse(peCertificateFixture(false, payload));
+    expect(report.coverage).toMatchObject({
+      status: "complete",
+      certificates: 1,
+    });
+    expect(report.entries[0]?.pkcs7?.signers[0]).toMatchObject({
+      serial_hex: "11223344",
+    });
+  },
+);