Fix registry validation (#471)

The `signature` field can have a variable length depending on leading
zeroes in the raw bytes.

src/verify.test.ts

@@ -3,9 +3,30 @@ import { verify } from './verify';
 const MOCK_REGISTRY = `test\n`;
 const MOCK_PUBLIC_KEY =
   '0x0351e33621fd89183c3db90db7db2a518a91ad0534d1345d031625d33e581e495a';
+
 const MOCK_SIGNATURE = {
   signature:
-    '0x304402206d433e9172960de6717d94ae263e47eefacd3584a3274a452f8f9567b3a797db02201b2e423188fb3f9daa6ce6a8723f69df26bd3ceeee81f77250526b91e093614f',
+    '0x304402206d433e9172960de6717d94ae263e47eefacd3584a3274a452f8f9567b3a797db02201b2e423188fb3f9daa6ce6a8723f69df26bd3ceeee81f77250526b91e093614f' as const,
+  curve: 'secp256k1' as const,
+  format: 'DER' as const,
+};
+
+const MOCK_LONG_REGISTRY = '2';
+const MOCK_LONG_PUBLIC_KEY =
+  '0x03a885324b8520fba54a173999629952cfa1f97930c20902ec389f9c32c6ffbc40';
+const MOCK_LONG_SIGNATURE = {
+  signature:
+    '0x3045022100d601f4258b9db55994778fc7c24056f7089ff4c3976f9278ec2cea643e26dbd302205632524cb060bb82b7a966916016dca21bf8b52bb8569c87317112132ce02af0' as const,
+  curve: 'secp256k1' as const,
+  format: 'DER' as const,
+};
+
+const MOCK_SHORT_REGISTRY = '310';
+const MOCK_SHORT_PUBLIC_KEY =
+  '0x03a885324b8520fba54a173999629952cfa1f97930c20902ec389f9c32c6ffbc40';
+const MOCK_SHORT_SIGNATURE = {
+  signature:
+    '0x30430220434042b4f8fc06534c2023286d45d6433e75a477131cb38b1e5a89dc604ea3f5021f3f2b0fcbf7c5dfc1b517a19114467c65f751f6e2b402f2b6db7f94f92f6143' as const,
   curve: 'secp256k1' as const,
   format: 'DER' as const,
 };
@@ -21,6 +42,26 @@ describe('verify', () => {
     ).toBe(true);
   });
 
+  it('verifies a valid signature with a longer format', async () => {
+    expect(
+      verify({
+        registry: MOCK_LONG_REGISTRY,
+        signature: MOCK_LONG_SIGNATURE,
+        publicKey: MOCK_LONG_PUBLIC_KEY,
+      }),
+    ).toBe(true);
+  });
+
+  it('verifies a valid signature with a shorter format', async () => {
+    expect(
+      verify({
+        registry: MOCK_SHORT_REGISTRY,
+        signature: MOCK_SHORT_SIGNATURE,
+        publicKey: MOCK_SHORT_PUBLIC_KEY,
+      }),
+    ).toBe(true);
+  });
+
   it('rejects an invalid signature', async () => {
     expect(
       verify({

src/verify.ts

@@ -1,5 +1,6 @@
 import type { Hex } from '@metamask/utils';
 import {
+  StrictHexStruct,
   remove0x,
   stringToBytes,
   assertStruct,
@@ -8,10 +9,10 @@ import {
 import { secp256k1 } from '@noble/curves/secp256k1';
 import { sha256 } from '@noble/hashes/sha256';
 import type { Infer } from 'superstruct';
-import { literal, object, pattern, string } from 'superstruct';
+import { literal, object } from 'superstruct';
 
 export const SignatureStruct = object({
-  signature: pattern(string(), /0x[0-9a-f]{140}/u),
+  signature: StrictHexStruct,
   curve: literal('secp256k1'),
   format: literal('DER'),
 });