How to verify your Ledger signature of Gnosis Safe transaction

verifyLedgerSignature.js

const { TypedDataUtils } = require('eth-sig-util')
const { sha256 } = require('ethereumjs-util')

function generateSafeTxHash(safeAddress, txArgs) {
  const messageTypes = {
    EIP712Domain: [{ type: 'address', name: 'verifyingContract' }],
    SafeTx: [
      { type: 'address', name: 'to' },
      { type: 'uint256', name: 'value' },
      { type: 'bytes', name: 'data' },
      { type: 'uint8', name: 'operation' },
      { type: 'uint256', name: 'safeTxGas' },
      { type: 'uint256', name: 'baseGas' },
      { type: 'uint256', name: 'gasPrice' },
      { type: 'address', name: 'gasToken' },
      { type: 'address', name: 'refundReceiver' },
      { type: 'uint256', name: 'nonce' },
    ],
  }

  const primaryType = 'SafeTx'

  const typedData = {
    types: messageTypes,
    domain: {
      verifyingContract: safeAddress,
    },
    primaryType,
    message: txArgs,
  }

  return TypedDataUtils.sign(typedData)
}

const safeTxHashBuffer = generateSafeTxHash(
  '0x0000000000000000000000000000000000000000', // Safe address
  {
    to: '0x0000000000000000000000000000000000000000',
    value: '0',
    data: '0x',
    operation: '0',
    safeTxGas: '0',
    baseGas: '0',
    gasPrice: '0',
    gasToken: '0x0000000000000000000000000000000000000000',
    refundReceiver: '0x0000000000000000000000000000000000000000',
    nonce: 0,
  }
)

const dataHashBuf = sha256(safeTxHashBuffer)

console.log(`safeTxHash: 0x${safeTxHashBuffer.toString('hex')}`)

console.log(`ledgerSignature: 0x${dataHashBuf.toString('hex')}`)