fix(firo): parse OP_PUSHDATA1 OP_RETURN data

.changeset/firo-pushdata1-op-return.md

@@ -0,0 +1,5 @@
+---
+'@rosen-bridge/rosen-extractor': patch
+---
+
+Fix Firo OP_RETURN parsing for OP_PUSHDATA1 payloads.

packages/rosen-extractor/lib/getRosenData/firo/utils.ts

@@ -3,6 +3,12 @@ import { address } from 'bitcoinjs-lib';
 import { MinimalOnChainRosenData } from '../../types';
 import { parseRosenData } from '../../utils';
 
+const OP_RETURN = 0x6a;
+const OP_PUSHDATA1 = 0x4c;
+const OP_PUSHDATA2 = 0x4d;
+const OP_PUSHDATA4 = 0x4e;
+const MAX_OP_RETURN_DATA_BYTES = 80;
+
 const firoNetwork = {
   // Firo network parameters
   messagePrefix: '\x19Firo Signed Message:\n',
@@ -16,6 +22,64 @@ const firoNetwork = {
   wif: 0xd2,
 };
 
+/**
+ * Extracts Rosen OP_RETURN payload from a Firo scriptPubKey.
+ *
+ * Supports direct push and OP_PUSHDATA1/2/4 encodings while enforcing Rosen's
+ * 80-byte OP_RETURN payload limit.
+ *
+ * @param scriptPubKeyHex Firo scriptPubKey hex
+ * @returns OP_RETURN payload hex
+ */
+const parseOpReturnData = (scriptPubKeyHex: string): string => {
+  if (scriptPubKeyHex.length % 2 !== 0) throw Error(`script hex length is odd`);
+
+  const scriptLength = scriptPubKeyHex.length / 2;
+  let offset = 0;
+
+  const readBytes = (length: number) => {
+    if (offset + length > scriptLength)
+      throw Error(
+        `script length is unexpected [${offset + length} > ${scriptLength}]`,
+      );
+
+    const result = scriptPubKeyHex.slice(offset * 2, (offset + length) * 2);
+    offset += length;
+    return result;
+  };
+
+  const opcode = parseInt(readBytes(1), 16);
+  if (opcode !== OP_RETURN)
+    throw Error(`script does not start with OP_RETURN opcode (6a)`);
+
+  const pushOpcode = parseInt(readBytes(1), 16);
+  let dataLength: number;
+  if (pushOpcode < OP_PUSHDATA1) {
+    dataLength = pushOpcode;
+  } else if (pushOpcode === OP_PUSHDATA1) {
+    dataLength = parseInt(readBytes(1), 16);
+  } else if (pushOpcode === OP_PUSHDATA2) {
+    dataLength = Buffer.from(readBytes(2), 'hex').readUInt16LE();
+  } else if (pushOpcode === OP_PUSHDATA4) {
+    dataLength = Buffer.from(readBytes(4), 'hex').readUInt32LE();
+  } else {
+    throw Error(`script contains unsupported push opcode [${pushOpcode}]`);
+  }
+
+  if (dataLength > MAX_OP_RETURN_DATA_BYTES)
+    throw Error(
+      `OP_RETURN data length exceeds Rosen limit [${dataLength} > ${MAX_OP_RETURN_DATA_BYTES}]`,
+    );
+
+  const expectedScriptLength = offset + dataLength;
+  if (Number.isNaN(dataLength) || expectedScriptLength !== scriptLength)
+    throw Error(
+      `script length is unexpected [${expectedScriptLength} !== ${scriptLength}]`,
+    );
+
+  return readBytes(dataLength);
+};
+
 /**
  * Converts a Firocoin address to its corresponding output script
  * @param addr The Firocoin address to convert
@@ -38,20 +102,5 @@ export const addressToOutputScript = (addr: string): string => {
 export const parseOpReturn = (
   scriptPubKeyHex: string,
 ): MinimalOnChainRosenData => {
-  // check OP_RETURN opcode
-  if (scriptPubKeyHex.slice(0, 2) !== '6a')
-    throw Error(`script does not start with OP_RETURN opcode (6a)`);
-
-  // check script length (should not use more than one OP_RETURN)
-  const dataLength = scriptPubKeyHex.slice(2, 4);
-  if (parseInt(dataLength, 16) + 2 !== scriptPubKeyHex.length / 2)
-    throw Error(
-      `script length is unexpected [${parseInt(dataLength, 16) + 3} !== ${
-        scriptPubKeyHex.length / 2
-      }]`,
-    );
-
-  const remainingData = scriptPubKeyHex.slice(4);
-
-  return parseRosenData(remainingData);
+  return parseRosenData(parseOpReturnData(scriptPubKeyHex));
 };

packages/rosen-extractor/tests/getRosenData/firo/utils.spec.ts

@@ -22,6 +22,43 @@ describe('parseOpReturn', () => {
     expect(result).toStrictEqual(testData.opReturnData);
   });
 
+  /**
+   * @target parseOpReturn should extract rosen data from %s
+   * @dependencies
+   * @scenario
+   * - mock OP_RETURN scriptPubKeys using OP_PUSHDATA1, OP_PUSHDATA2 and OP_PUSHDATA4
+   * - run test for each script
+   * - check returned value
+   * @expected
+   * - it should return expected rosen data
+   */
+  it.each([
+    ['OP_PUSHDATA1', testData.opReturnScripts.validPushData1],
+    ['OP_PUSHDATA2', testData.opReturnScripts.validPushData2],
+    ['OP_PUSHDATA4', testData.opReturnScripts.validPushData4],
+  ])('should extract rosen data from %s', (_pushDataEncoding, script) => {
+    const result = parseOpReturn(script);
+
+    expect(result).toStrictEqual(testData.opReturnData);
+  });
+
+  /**
+   * @target parseOpReturn should reject OP_RETURN data over Rosen 80-byte limit
+   * @dependencies
+   * @scenario
+   * - mock OP_RETURN scriptPubKey with OP_PUSHDATA1 and 81-byte payload
+   * - run test & check thrown exception
+   * @expected
+   * - it should throw error
+   */
+  it('should reject OP_RETURN data over Rosen 80-byte limit', () => {
+    const script = testData.opReturnScripts.tooLongPushData1;
+
+    expect(() => {
+      parseOpReturn(script);
+    }).toThrow('OP_RETURN data length exceeds Rosen limit [81 > 80]');
+  });
+
   /**
    * @target parseOpReturn should throw error
    * when script does not start with OP_RETURN opcode

packages/rosen-extractor/tests/getRosenData/firo/utilsTestData.ts

@@ -2,9 +2,18 @@ export const validFiroAddress = 'a3io3zMLfg9nchA3KSoSEvPz1tztnKDuaT';
 export const validFiroOutputScript =
   '76a91420f87f7f202c3d40dea06df136862fdbeef3f8e788ac';
 export const invalidFiroAddress = 'a3io3zMLfg9nchA3KSoSEvPz1tztnKDUZZ';
+const validOpReturnPayload =
+  '00000000000098968000000000009896802103f999da8e6e42660e4464d17d29e63bc006734a6710a24eb489b466323d3a9339';
+const padOpReturnPayload = (length: number) =>
+  validOpReturnPayload + '00'.repeat(length - validOpReturnPayload.length / 2);
+const pushData1Script = (length: number) =>
+  `6a4c${length.toString(16).padStart(2, '0')}${padOpReturnPayload(length)}`;
 export const opReturnScripts = {
-  valid:
-    '6a3300000000000098968000000000009896802103f999da8e6e42660e4464d17d29e63bc006734a6710a24eb489b466323d3a9339',
+  valid: `6a33${validOpReturnPayload}`,
+  validPushData1: pushData1Script(76),
+  validPushData2: `6a4d3300${validOpReturnPayload}`,
+  validPushData4: `6a4e33000000${validOpReturnPayload}`,
+  tooLongPushData1: pushData1Script(81),
   noOpReturn:
     '3300000000000098968000000000009896802103f999da8e6e42660e4464d17d29e63bc006734a6710a24eb489b466323d3a9339',
   invalidToChain: