check-ethereum-scanner/Ethereum-Renounced-Contract-Scanner-backup/node_modules/@ethereumjs/tx/src/legacyTransaction.ts

Safety checks for new Ethereum tokens

import {
  BN,
  bnToHex,
  bnToUnpaddedBuffer,
  ecrecover,
  MAX_INTEGER,
  rlp,
  rlphash,
  toBuffer,
  unpadBuffer,
  validateNoLeadingZeroes,
} from 'ethereumjs-util'
import { TxOptions, TxData, JsonTx, N_DIV_2, TxValuesArray, Capability } from './types'
import { BaseTransaction } from './baseTransaction'
import Common from '@ethereumjs/common'
import { checkMaxInitCodeSize } from './util'

const TRANSACTION_TYPE = 0

/**
 * An Ethereum non-typed (legacy) transaction
 */
export default class Transaction extends BaseTransaction<Transaction> {
  public readonly gasPrice: BN

  public readonly common: Common

  /**
   * Instantiate a transaction from a data dictionary.
   *
   * Format: { nonce, gasPrice, gasLimit, to, value, data, v, r, s }
   *
   * Notes:
   * - All parameters are optional and have some basic default values
   */
  public static fromTxData(txData: TxData, opts: TxOptions = {}) {
    return new Transaction(txData, opts)
  }

  /**
   * Instantiate a transaction from the serialized tx.
   *
   * Format: `rlp([nonce, gasPrice, gasLimit, to, value, data, v, r, s])`
   */
  public static fromSerializedTx(serialized: Buffer, opts: TxOptions = {}) {
    const values = rlp.decode(serialized)

    if (!Array.isArray(values)) {
      throw new Error('Invalid serialized tx input. Must be array')
    }

    return this.fromValuesArray(values, opts)
  }

  /**
   * Instantiate a transaction from the serialized tx.
   * (alias of {@link Transaction.fromSerializedTx})
   *
   * @deprecated this constructor alias is deprecated and will be removed
   * in favor of the {@link Transaction.fromSerializedTx} constructor
   */
  public static fromRlpSerializedTx(serialized: Buffer, opts: TxOptions = {}) {
    return Transaction.fromSerializedTx(serialized, opts)
  }

  /**
   * Create a transaction from a values array.
   *
   * Format: `[nonce, gasPrice, gasLimit, to, value, data, v, r, s]`
   */
  public static fromValuesArray(values: TxValuesArray, opts: TxOptions = {}) {
    // If length is not 6, it has length 9. If v/r/s are empty Buffers, it is still an unsigned transaction
    // This happens if you get the RLP data from `raw()`
    if (values.length !== 6 && values.length !== 9) {
      throw new Error(
        'Invalid transaction. Only expecting 6 values (for unsigned tx) or 9 values (for signed tx).'
      )
    }

    const [nonce, gasPrice, gasLimit, to, value, data, v, r, s] = values

    validateNoLeadingZeroes({ nonce, gasPrice, gasLimit, value, v, r, s })

    return new Transaction(
      {
        nonce,
        gasPrice,
        gasLimit,
        to,
        value,
        data,
        v,
        r,
        s,
      },
      opts
    )
  }

  /**
   * This constructor takes the values, validates them, assigns them and freezes the object.
   *
   * It is not recommended to use this constructor directly. Instead use
   * the static factory methods to assist in creating a Transaction object from
   * varying data types.
   */
  public constructor(txData: TxData, opts: TxOptions = {}) {
    super({ ...txData, type: TRANSACTION_TYPE }, opts)

    this.common = this._validateTxV(this.v, opts.common)

    this.gasPrice = new BN(toBuffer(txData.gasPrice === '' ? '0x' : txData.gasPrice))

    if (this.gasPrice.mul(this.gasLimit).gt(MAX_INTEGER)) {
      const msg = this._errorMsg('gas limit * gasPrice cannot exceed MAX_INTEGER (2^256-1)')
      throw new Error(msg)
    }
    this._validateCannotExceedMaxInteger({ gasPrice: this.gasPrice })

    if (this.common.gteHardfork('spuriousDragon')) {
      if (!this.isSigned()) {
        this.activeCapabilities.push(Capability.EIP155ReplayProtection)
      } else {
        // EIP155 spec:
        // If block.number >= 2,675,000 and v = CHAIN_ID * 2 + 35 or v = CHAIN_ID * 2 + 36
        // then when computing the hash of a transaction for purposes of signing or recovering
        // instead of hashing only the first six elements (i.e. nonce, gasprice, startgas, to, value, data)
        // hash nine elements, with v replaced by CHAIN_ID, r = 0 and s = 0.
        const v = this.v!
        const chainIdDoubled = this.common.chainIdBN().muln(2)

        // v and chain ID meet EIP-155 conditions
        if (v.eq(chainIdDoubled.addn(35)) || v.eq(chainIdDoubled.addn(36))) {
          this.activeCapabilities.push(Capability.EIP155ReplayProtection)
        }
      }
    }

    if (this.common.isActivatedEIP(3860)) {
      checkMaxInitCodeSize(this.common, this.data.length)
    }

    const freeze = opts?.freeze ?? true
    if (freeze) {
      Object.freeze(this)
    }
  }

  /**
   * Returns a Buffer Array of the raw Buffers of the legacy transaction, in order.
   *
   * Format: `[nonce, gasPrice, gasLimit, to, value, data, v, r, s]`
   *
   * For legacy txs this is also the correct format to add transactions
   * to a block with {@link Block.fromValuesArray} (use the `serialize()` method
   * for typed txs).
   *
   * For an unsigned tx this method returns the empty Buffer values
   * for the signature parameters `v`, `r` and `s`. For an EIP-155 compliant
   * representation have a look at {@link Transaction.getMessageToSign}.
   */
  raw(): TxValuesArray {
    return [
      bnToUnpaddedBuffer(this.nonce),
      bnToUnpaddedBuffer(this.gasPrice),
      bnToUnpaddedBuffer(this.gasLimit),
      this.to !== undefined ? this.to.buf : Buffer.from([]),
      bnToUnpaddedBuffer(this.value),
      this.data,
      this.v !== undefined ? bnToUnpaddedBuffer(this.v) : Buffer.from([]),
      this.r !== undefined ? bnToUnpaddedBuffer(this.r) : Buffer.from([]),
      this.s !== undefined ? bnToUnpaddedBuffer(this.s) : Buffer.from([]),
    ]
  }

  /**
   * Returns the serialized encoding of the legacy transaction.
   *
   * Format: `rlp([nonce, gasPrice, gasLimit, to, value, data, v, r, s])`
   *
   * For an unsigned tx this method uses the empty Buffer values for the
   * signature parameters `v`, `r` and `s` for encoding. For an EIP-155 compliant
   * representation for external signing use {@link Transaction.getMessageToSign}.
   */
  serialize(): Buffer {
    return rlp.encode(this.raw())
  }

  private _getMessageToSign() {
    const values = [
      bnToUnpaddedBuffer(this.nonce),
      bnToUnpaddedBuffer(this.gasPrice),
      bnToUnpaddedBuffer(this.gasLimit),
      this.to !== undefined ? this.to.buf : Buffer.from([]),
      bnToUnpaddedBuffer(this.value),
      this.data,
    ]

    if (this.supports(Capability.EIP155ReplayProtection)) {
      values.push(toBuffer(this.common.chainIdBN()))
      values.push(unpadBuffer(toBuffer(0)))
      values.push(unpadBuffer(toBuffer(0)))
    }

    return values
  }

  /**
   * Returns the unsigned tx (hashed or raw), which can be used
   * to sign the transaction (e.g. for sending to a hardware wallet).
   *
   * Note: the raw message message format for the legacy tx is not RLP encoded
   * and you might need to do yourself with:
   *
   * ```javascript
   * import { rlp } from 'ethereumjs-util'
   * const message = tx.getMessageToSign(false)
   * const serializedMessage = rlp.encode(message) // use this for the HW wallet input
   * ```
   *
   * @param hashMessage - Return hashed message if set to true (default: true)
   */
  getMessageToSign(hashMessage: false): Buffer[]
  getMessageToSign(hashMessage?: true): Buffer
  getMessageToSign(hashMessage = true) {
    const message = this._getMessageToSign()
    if (hashMessage) {
      return rlphash(message)
    } else {
      return message
    }
  }

  /**
   * The amount of gas paid for the data in this tx
   */
  getDataFee(): BN {
    if (this.cache.dataFee && this.cache.dataFee.hardfork === this.common.hardfork()) {
      return this.cache.dataFee.value
    }

    if (Object.isFrozen(this)) {
      this.cache.dataFee = {
        value: super.getDataFee(),
        hardfork: this.common.hardfork(),
      }
    }

    return super.getDataFee()
  }

  /**
   * The up front amount that an account must have for this transaction to be valid
   */
  getUpfrontCost(): BN {
    return this.gasLimit.mul(this.gasPrice).add(this.value)
  }

  /**
   * Computes a sha3-256 hash of the serialized tx.
   *
   * This method can only be used for signed txs (it throws otherwise).
   * Use {@link Transaction.getMessageToSign} to get a tx hash for the purpose of signing.
   */
  hash(): Buffer {
    // In contrast to the tx type transaction implementations the `hash()` function
    // for the legacy tx does not throw if the tx is not signed.
    // This has been considered for inclusion but lead to unexpected backwards
    // compatibility problems (no concrete reference found, needs validation).
    //
    // For context see also https://github.com/ethereumjs/ethereumjs-monorepo/pull/1445,
    // September, 2021 as well as work done before.
    //
    // This should be updated along the next major version release by adding:
    //
    //if (!this.isSigned()) {
    //  const msg = this._errorMsg('Cannot call hash method if transaction is not signed')
    //  throw new Error(msg)
    //}

    if (Object.isFrozen(this)) {
      if (!this.cache.hash) {
        this.cache.hash = rlphash(this.raw())
      }
      return this.cache.hash
    }

    return rlphash(this.raw())
  }

  /**
   * Computes a sha3-256 hash which can be used to verify the signature
   */
  getMessageToVerifySignature() {
    if (!this.isSigned()) {
      const msg = this._errorMsg('This transaction is not signed')
      throw new Error(msg)
    }
    const message = this._getMessageToSign()
    return rlphash(message)
  }

  /**
   * Returns the public key of the sender
   */
  getSenderPublicKey(): Buffer {
    const msgHash = this.getMessageToVerifySignature()

    // EIP-2: All transaction signatures whose s-value is greater than secp256k1n/2 are considered invalid.
    // Reasoning: https://ethereum.stackexchange.com/a/55728
    if (this.common.gteHardfork('homestead') && this.s?.gt(N_DIV_2)) {
      const msg = this._errorMsg(
        'Invalid Signature: s-values greater than secp256k1n/2 are considered invalid'
      )
      throw new Error(msg)
    }

    const { v, r, s } = this
    try {
      return ecrecover(
        msgHash,
        v!,
        bnToUnpaddedBuffer(r!),
        bnToUnpaddedBuffer(s!),
        this.supports(Capability.EIP155ReplayProtection) ? this.common.chainIdBN() : undefined
      )
    } catch (e: any) {
      const msg = this._errorMsg('Invalid Signature')
      throw new Error(msg)
    }
  }

  /**
   * Process the v, r, s values from the `sign` method of the base transaction.
   */
  protected _processSignature(v: number, r: Buffer, s: Buffer) {
    const vBN = new BN(v)
    if (this.supports(Capability.EIP155ReplayProtection)) {
      vBN.iadd(this.common.chainIdBN().muln(2).addn(8))
    }

    const opts = { ...this.txOptions, common: this.common }

    return Transaction.fromTxData(
      {
        nonce: this.nonce,
        gasPrice: this.gasPrice,
        gasLimit: this.gasLimit,
        to: this.to,
        value: this.value,
        data: this.data,
        v: vBN,
        r: new BN(r),
        s: new BN(s),
      },
      opts
    )
  }

  /**
   * Returns an object with the JSON representation of the transaction.
   */
  toJSON(): JsonTx {
    return {
      nonce: bnToHex(this.nonce),
      gasPrice: bnToHex(this.gasPrice),
      gasLimit: bnToHex(this.gasLimit),
      to: this.to !== undefined ? this.to.toString() : undefined,
      value: bnToHex(this.value),
      data: '0x' + this.data.toString('hex'),
      v: this.v !== undefined ? bnToHex(this.v) : undefined,
      r: this.r !== undefined ? bnToHex(this.r) : undefined,
      s: this.s !== undefined ? bnToHex(this.s) : undefined,
    }
  }

  /**
   * Validates tx's `v` value
   */
  private _validateTxV(v?: BN, common?: Common): Common {
    // Check for valid v values in the scope of a signed legacy tx
    if (v !== undefined) {
      // v is 1. not matching the EIP-155 chainId included case and...
      // v is 2. not matching the classic v=27 or v=28 case
      if (v.ltn(37) && !v.eqn(27) && !v.eqn(28)) {
        throw new Error(
          `Legacy txs need either v = 27/28 or v >= 37 (EIP-155 replay protection), got v = ${v}`
        )
      }
    }

    let chainIdBN
    // No unsigned tx and EIP-155 activated and chain ID included
    if (
      v !== undefined &&
      (!common || common.gteHardfork('spuriousDragon')) &&
      !v.eqn(27) &&
      !v.eqn(28)
    ) {
      if (common) {
        const chainIdDoubled = common.chainIdBN().muln(2)
        const isValidEIP155V = v.eq(chainIdDoubled.addn(35)) || v.eq(chainIdDoubled.addn(36))

        if (!isValidEIP155V) {
          throw new Error(
            `Incompatible EIP155-based V ${v} and chain id ${common.chainIdBN()}. See the Common parameter of the Transaction constructor to set the chain id.`
          )
        }
      } else {
        // Derive the original chain ID
        let numSub
        if (v.subn(35).isEven()) {
          numSub = 35
        } else {
          numSub = 36
        }
        // Use derived chain ID to create a proper Common
        chainIdBN = v.subn(numSub).divn(2)
      }
    }
    return this._getCommon(common, chainIdBN)
  }

  /**
   * @deprecated if you have called this internal method please use `tx.supports(Capabilities.EIP155ReplayProtection)` instead
   */
  private _unsignedTxImplementsEIP155() {
    return this.common.gteHardfork('spuriousDragon')
  }

  /**
   * @deprecated if you have called this internal method please use `tx.supports(Capabilities.EIP155ReplayProtection)` instead
   */
  private _signedTxImplementsEIP155() {
    if (!this.isSigned()) {
      const msg = this._errorMsg('This transaction is not signed')
      throw new Error(msg)
    }
    const onEIP155BlockOrLater = this.common.gteHardfork('spuriousDragon')

    // EIP155 spec:
    // If block.number >= 2,675,000 and v = CHAIN_ID * 2 + 35 or v = CHAIN_ID * 2 + 36, then when computing the hash of a transaction for purposes of signing or recovering, instead of hashing only the first six elements (i.e. nonce, gasprice, startgas, to, value, data), hash nine elements, with v replaced by CHAIN_ID, r = 0 and s = 0.
    const v = this.v!

    const chainIdDoubled = this.common.chainIdBN().muln(2)

    const vAndChainIdMeetEIP155Conditions =
      v.eq(chainIdDoubled.addn(35)) || v.eq(chainIdDoubled.addn(36))

    return vAndChainIdMeetEIP155Conditions && onEIP155BlockOrLater
  }

  /**
   * Return a compact error string representation of the object
   */
  public errorStr() {
    let errorStr = this._getSharedErrorPostfix()
    errorStr += ` gasPrice=${this.gasPrice}`
    return errorStr
  }

  /**
   * Internal helper function to create an annotated error message
   *
   * @param msg Base error message
   * @hidden
   */
  protected _errorMsg(msg: string) {
    return `${msg} (${this.errorStr()})`
  }
}