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import { schemas } from '@0xproject/json-schemas';
import { ECSignature, Provider } from '@0xproject/types';
import { Web3Wrapper } from '@0xproject/web3-wrapper';
import * as ethUtil from 'ethereumjs-util';
import * as _ from 'lodash';
import { assert } from './assert';
import { OrderError } from './types';
/**
* Verifies that the elliptic curve signature `signature` was generated
* by signing `data` with the private key corresponding to the `signerAddress` address.
* @param data The hex encoded data signed by the supplied signature.
* @param signature An object containing the elliptic curve signature parameters.
* @param signerAddress The hex encoded address that signed the data, producing the supplied signature.
* @return Whether the signature is valid for the supplied signerAddress and data.
*/
export function isValidSignature(data: string, signature: ECSignature, signerAddress: string): boolean {
assert.isHexString('data', data);
assert.doesConformToSchema('signature', signature, schemas.ecSignatureSchema);
assert.isETHAddressHex('signerAddress', signerAddress);
const normalizedSignerAddress = signerAddress.toLowerCase();
const dataBuff = ethUtil.toBuffer(data);
const msgHashBuff = ethUtil.hashPersonalMessage(dataBuff);
try {
const pubKey = ethUtil.ecrecover(
msgHashBuff,
signature.v,
ethUtil.toBuffer(signature.r),
ethUtil.toBuffer(signature.s),
);
const retrievedAddress = ethUtil.bufferToHex(ethUtil.pubToAddress(pubKey));
return retrievedAddress === signerAddress;
} catch (err) {
return false;
}
}
/**
* Signs an orderHash and returns it's elliptic curve signature.
* This method currently supports TestRPC, Geth and Parity above and below V1.6.6
* @param orderHash Hex encoded orderHash to sign.
* @param signerAddress The hex encoded Ethereum address you wish to sign it with. This address
* must be available via the Provider supplied to 0x.js.
* @param shouldAddPersonalMessagePrefix Some signers add the personal message prefix `\x19Ethereum Signed Message`
* themselves (e.g Parity Signer, Ledger, TestRPC) and others expect it to already be done by the client
* (e.g Metamask). Depending on which signer this request is going to, decide on whether to add the prefix
* before sending the request.
* @return An object containing the Elliptic curve signature parameters generated by signing the orderHash.
*/
export async function signOrderHashAsync(
provider: Provider,
orderHash: string,
signerAddress: string,
shouldAddPersonalMessagePrefix: boolean,
): Promise<ECSignature> {
assert.isHexString('orderHash', orderHash);
const web3Wrapper = new Web3Wrapper(provider);
await assert.isSenderAddressAsync('signerAddress', signerAddress, web3Wrapper);
const normalizedSignerAddress = signerAddress.toLowerCase();
let msgHashHex = orderHash;
if (shouldAddPersonalMessagePrefix) {
const orderHashBuff = ethUtil.toBuffer(orderHash);
const msgHashBuff = ethUtil.hashPersonalMessage(orderHashBuff);
msgHashHex = ethUtil.bufferToHex(msgHashBuff);
}
const signature = await web3Wrapper.signMessageAsync(normalizedSignerAddress, msgHashHex);
// HACK: There is no consensus on whether the signatureHex string should be formatted as
// v + r + s OR r + s + v, and different clients (even different versions of the same client)
// return the signature params in different orders. In order to support all client implementations,
// we parse the signature in both ways, and evaluate if either one is a valid signature.
// tslint:disable-next-line:custom-no-magic-numbers
const validVParamValues = [27, 28];
const ecSignatureVRS = parseSignatureHexAsVRS(signature);
if (_.includes(validVParamValues, ecSignatureVRS.v)) {
const isValidVRSSignature = isValidSignature(orderHash, ecSignatureVRS, normalizedSignerAddress);
if (isValidVRSSignature) {
return ecSignatureVRS;
}
}
const ecSignatureRSV = parseSignatureHexAsRSV(signature);
if (_.includes(validVParamValues, ecSignatureRSV.v)) {
const isValidRSVSignature = isValidSignature(orderHash, ecSignatureRSV, normalizedSignerAddress);
if (isValidRSVSignature) {
return ecSignatureRSV;
}
}
throw new Error(OrderError.InvalidSignature);
}
function parseSignatureHexAsVRS(signatureHex: string): ECSignature {
const signatureBuffer = ethUtil.toBuffer(signatureHex);
let v = signatureBuffer[0];
// HACK: Sometimes v is returned as [0, 1] and sometimes as [27, 28]
// If it is returned as [0, 1], add 27 to both so it becomes [27, 28]
const lowestValidV = 27;
const isProperlyFormattedV = v >= lowestValidV;
if (!isProperlyFormattedV) {
v += lowestValidV;
}
// signatureBuffer contains vrs
const vEndIndex = 1;
const rsIndex = 33;
const r = signatureBuffer.slice(vEndIndex, rsIndex);
const sEndIndex = 65;
const s = signatureBuffer.slice(rsIndex, sEndIndex);
const ecSignature: ECSignature = {
v,
r: ethUtil.bufferToHex(r),
s: ethUtil.bufferToHex(s),
};
return ecSignature;
}
function parseSignatureHexAsRSV(signatureHex: string): ECSignature {
const { v, r, s } = ethUtil.fromRpcSig(signatureHex);
const ecSignature: ECSignature = {
v,
r: ethUtil.bufferToHex(r),
s: ethUtil.bufferToHex(s),
};
return ecSignature;
}
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