From aa9b7c959c41903df2bbe62100d2f61284ca2fd6 Mon Sep 17 00:00:00 2001
From: Jaco <jacogr@gmail.com>
Date: Mon, 14 Jun 2021 10:47:04 +0300
Subject: [PATCH] Don't wrap/unwrap Ethereum-style (#748)

* Don't wrap/unwrap Ethereum-style

* Update packages/extension-dapp/src/wrapBytes.spec.ts
---
 packages/extension-dapp/src/wrapBytes.spec.ts | 23 +++++++++++++++++-
 packages/extension-dapp/src/wrapBytes.ts      | 24 ++++++++++++++-----
 2 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/packages/extension-dapp/src/wrapBytes.spec.ts b/packages/extension-dapp/src/wrapBytes.spec.ts
index 1af4bcd0..6f9b7676 100644
--- a/packages/extension-dapp/src/wrapBytes.spec.ts
+++ b/packages/extension-dapp/src/wrapBytes.spec.ts
@@ -3,9 +3,10 @@
 
 import { u8aConcat, u8aEq, u8aToString } from '@polkadot/util';
 
-import { POSTFIX, PREFIX, unwrapBytes, wrapBytes } from './wrapBytes';
+import { ETHEREUM, POSTFIX, PREFIX, unwrapBytes, wrapBytes } from './wrapBytes';
 
 const TEST_DATA = 'this is just some random message that we expect to be wrapped along the way';
+const TEST_ETH = u8aConcat(ETHEREUM, TEST_DATA);
 const TEST_WRAP_EMPTY = `${u8aToString(PREFIX)}${u8aToString(POSTFIX)}`;
 const TEST_WRAP_FULL = `${u8aToString(PREFIX)}${TEST_DATA}${u8aToString(POSTFIX)}`;
 const TEST_WARP_HALF_PRE = `${u8aToString(PREFIX)}${TEST_DATA}`;
@@ -111,4 +112,24 @@ describe('unwrapBytes', (): void => {
       )
     ).toEqual('');
   });
+
+  describe('Ethereum-style', (): void => {
+    it('does not wrap an Ethereum wrap', (): void => {
+      expect(
+        u8aEq(
+          wrapBytes(TEST_ETH),
+          TEST_ETH
+        )
+      ).toBe(true);
+    });
+
+    it('does not unwrap an Ethereum wrap', (): void => {
+      expect(
+        u8aEq(
+          unwrapBytes(TEST_ETH),
+          TEST_ETH
+        )
+      ).toBe(true);
+    });
+  });
 });
diff --git a/packages/extension-dapp/src/wrapBytes.ts b/packages/extension-dapp/src/wrapBytes.ts
index 7ce606f2..a5dcc12c 100644
--- a/packages/extension-dapp/src/wrapBytes.ts
+++ b/packages/extension-dapp/src/wrapBytes.ts
@@ -3,21 +3,32 @@
 
 import { u8aConcat, u8aEq, u8aToU8a } from '@polkadot/util';
 
+export const ETHEREUM = u8aToU8a('\x19Ethereum Signed Message:\n');
 export const PREFIX = u8aToU8a('<Bytes>');
 export const POSTFIX = u8aToU8a('</Bytes>');
 
 const WRAP_LEN = PREFIX.length + POSTFIX.length;
 
-function isWrapped (u8a: Uint8Array): boolean {
-  return u8a.length >= WRAP_LEN &&
-    u8aEq(u8a.subarray(0, PREFIX.length), PREFIX) &&
-    u8aEq(u8a.slice(-POSTFIX.length), POSTFIX);
+function isWrapped (u8a: Uint8Array, withEthereum: boolean): boolean {
+  return (
+    (
+      u8a.length >= WRAP_LEN &&
+      u8aEq(u8a.subarray(0, PREFIX.length), PREFIX) &&
+      u8aEq(u8a.slice(-POSTFIX.length), POSTFIX)
+    ) ||
+    (
+      withEthereum &&
+      u8a.length >= ETHEREUM.length &&
+      u8aEq(u8a.subarray(0, ETHEREUM.length), ETHEREUM)
+    )
+  );
 }
 
 export function unwrapBytes (bytes: string | Uint8Array): Uint8Array {
   const u8a = u8aToU8a(bytes);
 
-  return isWrapped(u8a)
+  // we don't want to unwrap Ethereum-style wraps
+  return isWrapped(u8a, false)
     ? u8a.subarray(PREFIX.length, u8a.length - POSTFIX.length)
     : u8a;
 }
@@ -25,7 +36,8 @@ export function unwrapBytes (bytes: string | Uint8Array): Uint8Array {
 export function wrapBytes (bytes: string | Uint8Array): Uint8Array {
   const u8a = u8aToU8a(bytes);
 
-  return isWrapped(u8a)
+  // if Ethereum-wrapping, we don't add our wrapping bytes
+  return isWrapped(u8a, true)
     ? u8a
     : u8aConcat(PREFIX, u8a, POSTFIX);
 }