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eip712.go
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eip712.go
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package cosmos
import (
"fmt"
errorsmod "cosmossdk.io/errors"
"github.com/servprotocolorg/serv/v12/crypto/ethsecp256k1"
"github.com/servprotocolorg/serv/v12/ethereum/eip712"
"github.com/servprotocolorg/serv/v12/types"
"github.com/cosmos/cosmos-sdk/codec"
codectypes "github.com/cosmos/cosmos-sdk/codec/types"
cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
sdk "github.com/cosmos/cosmos-sdk/types"
errortypes "github.com/cosmos/cosmos-sdk/types/errors"
"github.com/cosmos/cosmos-sdk/types/tx/signing"
authante "github.com/cosmos/cosmos-sdk/x/auth/ante"
"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
authsigning "github.com/cosmos/cosmos-sdk/x/auth/signing"
ethcrypto "github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/crypto/secp256k1"
"github.com/ethereum/go-ethereum/signer/core/apitypes"
evmtypes "github.com/servprotocolorg/serv/v12/x/evm/types"
)
var servCodec codec.ProtoCodecMarshaler
func init() {
registry := codectypes.NewInterfaceRegistry()
types.RegisterInterfaces(registry)
servCodec = codec.NewProtoCodec(registry)
}
// Deprecated: LegacyEip712SigVerificationDecorator Verify all signatures for a tx and return an error if any are invalid. Note,
// the LegacyEip712SigVerificationDecorator decorator will not get executed on ReCheck.
// NOTE: As of v10, EIP-712 signature verification is handled by the ethsecp256k1 public key (see ethsecp256k1.go)
//
// CONTRACT: Pubkeys are set in context for all signers before this decorator runs
// CONTRACT: Tx must implement SigVerifiableTx interface
type LegacyEip712SigVerificationDecorator struct {
ak evmtypes.AccountKeeper
signModeHandler authsigning.SignModeHandler
}
// Deprecated: NewLegacyEip712SigVerificationDecorator creates a new LegacyEip712SigVerificationDecorator
func NewLegacyEip712SigVerificationDecorator(
ak evmtypes.AccountKeeper,
signModeHandler authsigning.SignModeHandler,
) LegacyEip712SigVerificationDecorator {
return LegacyEip712SigVerificationDecorator{
ak: ak,
signModeHandler: signModeHandler,
}
}
// AnteHandle handles validation of EIP712 signed cosmos txs.
// it is not run on RecheckTx
func (svd LegacyEip712SigVerificationDecorator) AnteHandle(ctx sdk.Context,
tx sdk.Tx,
simulate bool,
next sdk.AnteHandler,
) (newCtx sdk.Context, err error) {
// no need to verify signatures on recheck tx
if ctx.IsReCheckTx() {
return next(ctx, tx, simulate)
}
sigTx, ok := tx.(authsigning.SigVerifiableTx)
if !ok {
return ctx, errorsmod.Wrapf(errortypes.ErrInvalidType, "tx %T doesn't implement authsigning.SigVerifiableTx", tx)
}
authSignTx, ok := tx.(authsigning.Tx)
if !ok {
return ctx, errorsmod.Wrapf(errortypes.ErrInvalidType, "tx %T doesn't implement the authsigning.Tx interface", tx)
}
// stdSigs contains the sequence number, account number, and signatures.
// When simulating, this would just be a 0-length slice.
sigs, err := sigTx.GetSignaturesV2()
if err != nil {
return ctx, err
}
signerAddrs := sigTx.GetSigners()
// EIP712 allows just one signature
if len(sigs) != 1 {
return ctx, errorsmod.Wrapf(
errortypes.ErrTooManySignatures,
"invalid number of signers (%d); EIP712 signatures allows just one signature",
len(sigs),
)
}
// check that signer length and signature length are the same
if len(sigs) != len(signerAddrs) {
return ctx, errorsmod.Wrapf(errortypes.ErrorInvalidSigner, "invalid number of signers; expected: %d, got %d", len(signerAddrs), len(sigs))
}
// EIP712 has just one signature, avoid looping here and only read index 0
i := 0
sig := sigs[i]
acc, err := authante.GetSignerAcc(ctx, svd.ak, signerAddrs[i])
if err != nil {
return ctx, err
}
// retrieve pubkey
pubKey := acc.GetPubKey()
if !simulate && pubKey == nil {
return ctx, errorsmod.Wrap(errortypes.ErrInvalidPubKey, "pubkey on account is not set")
}
// Check account sequence number.
if sig.Sequence != acc.GetSequence() {
return ctx, errorsmod.Wrapf(
errortypes.ErrWrongSequence,
"account sequence mismatch, expected %d, got %d", acc.GetSequence(), sig.Sequence,
)
}
// retrieve signer data
genesis := ctx.BlockHeight() == 0
chainID := ctx.ChainID()
var accNum uint64
if !genesis {
accNum = acc.GetAccountNumber()
}
signerData := authsigning.SignerData{
ChainID: chainID,
AccountNumber: accNum,
Sequence: acc.GetSequence(),
}
if simulate {
return next(ctx, tx, simulate)
}
if err := VerifySignature(pubKey, signerData, sig.Data, svd.signModeHandler, authSignTx); err != nil {
errMsg := fmt.Errorf("signature verification failed; please verify account number (%d) and chain-id (%s): %w", accNum, chainID, err)
return ctx, errorsmod.Wrap(errortypes.ErrUnauthorized, errMsg.Error())
}
return next(ctx, tx, simulate)
}
// VerifySignature verifies a transaction signature contained in SignatureData abstracting over different signing modes
// and single vs multi-signatures.
func VerifySignature(
pubKey cryptotypes.PubKey,
signerData authsigning.SignerData,
sigData signing.SignatureData,
_ authsigning.SignModeHandler,
tx authsigning.Tx,
) error {
switch data := sigData.(type) {
case *signing.SingleSignatureData:
if data.SignMode != signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON {
return errorsmod.Wrapf(errortypes.ErrNotSupported, "unexpected SignatureData %T: wrong SignMode", sigData)
}
// Note: this prevents the user from sending trash data in the signature field
if len(data.Signature) != 0 {
return errorsmod.Wrap(errortypes.ErrTooManySignatures, "invalid signature value; EIP712 must have the cosmos transaction signature empty")
}
// @contract: this code is reached only when Msg has Web3Tx extension (so this custom Ante handler flow),
// and the signature is SIGN_MODE_LEGACY_AMINO_JSON which is supported for EIP712 for now
msgs := tx.GetMsgs()
if len(msgs) == 0 {
return errorsmod.Wrap(errortypes.ErrNoSignatures, "tx doesn't contain any msgs to verify signature")
}
txBytes := legacytx.StdSignBytes(
signerData.ChainID,
signerData.AccountNumber,
signerData.Sequence,
tx.GetTimeoutHeight(),
legacytx.StdFee{
Amount: tx.GetFee(),
Gas: tx.GetGas(),
},
msgs, tx.GetMemo(), tx.GetTip(),
)
signerChainID, err := types.ParseChainID(signerData.ChainID)
if err != nil {
return errorsmod.Wrapf(err, "failed to parse chain-id: %s", signerData.ChainID)
}
txWithExtensions, ok := tx.(authante.HasExtensionOptionsTx)
if !ok {
return errorsmod.Wrap(errortypes.ErrUnknownExtensionOptions, "tx doesnt contain any extensions")
}
opts := txWithExtensions.GetExtensionOptions()
if len(opts) != 1 {
return errorsmod.Wrap(errortypes.ErrUnknownExtensionOptions, "tx doesnt contain expected amount of extension options")
}
extOpt, ok := opts[0].GetCachedValue().(*types.ExtensionOptionsWeb3Tx)
if !ok {
return errorsmod.Wrap(errortypes.ErrUnknownExtensionOptions, "unknown extension option")
}
if extOpt.TypedDataChainID != signerChainID.Uint64() {
return errorsmod.Wrap(errortypes.ErrInvalidChainID, "invalid chain-id")
}
if len(extOpt.FeePayer) == 0 {
return errorsmod.Wrap(errortypes.ErrUnknownExtensionOptions, "no feePayer on ExtensionOptionsWeb3Tx")
}
feePayer, err := sdk.AccAddressFromBech32(extOpt.FeePayer)
if err != nil {
return errorsmod.Wrap(err, "failed to parse feePayer from ExtensionOptionsWeb3Tx")
}
feeDelegation := &eip712.FeeDelegationOptions{
FeePayer: feePayer,
}
typedData, err := eip712.LegacyWrapTxToTypedData(servCodec, extOpt.TypedDataChainID, msgs[0], txBytes, feeDelegation)
if err != nil {
return errorsmod.Wrap(err, "failed to create EIP-712 typed data from tx")
}
sigHash, _, err := apitypes.TypedDataAndHash(typedData)
if err != nil {
return err
}
feePayerSig := extOpt.FeePayerSig
if len(feePayerSig) != ethcrypto.SignatureLength {
return errorsmod.Wrap(errortypes.ErrorInvalidSigner, "signature length doesn't match typical [R||S||V] signature 65 bytes")
}
// Remove the recovery offset if needed (ie. Metamask eip712 signature)
if feePayerSig[ethcrypto.RecoveryIDOffset] == 27 || feePayerSig[ethcrypto.RecoveryIDOffset] == 28 {
feePayerSig[ethcrypto.RecoveryIDOffset] -= 27
}
feePayerPubkey, err := secp256k1.RecoverPubkey(sigHash, feePayerSig)
if err != nil {
return errorsmod.Wrap(err, "failed to recover delegated fee payer from sig")
}
ecPubKey, err := ethcrypto.UnmarshalPubkey(feePayerPubkey)
if err != nil {
return errorsmod.Wrap(err, "failed to unmarshal recovered fee payer pubkey")
}
pk := ðsecp256k1.PubKey{
Key: ethcrypto.CompressPubkey(ecPubKey),
}
if !pubKey.Equals(pk) {
return errorsmod.Wrapf(errortypes.ErrInvalidPubKey, "feePayer pubkey %s is different from transaction pubkey %s", pubKey, pk)
}
recoveredFeePayerAcc := sdk.AccAddress(pk.Address().Bytes())
if !recoveredFeePayerAcc.Equals(feePayer) {
return errorsmod.Wrapf(errortypes.ErrorInvalidSigner, "failed to verify delegated fee payer %s signature", recoveredFeePayerAcc)
}
// VerifySignature of ethsecp256k1 accepts 64 byte signature [R||S]
// WARNING! Under NO CIRCUMSTANCES try to use pubKey.VerifySignature there
if !secp256k1.VerifySignature(pubKey.Bytes(), sigHash, feePayerSig[:len(feePayerSig)-1]) {
return errorsmod.Wrap(errortypes.ErrorInvalidSigner, "unable to verify signer signature of EIP712 typed data")
}
return nil
default:
return errorsmod.Wrapf(errortypes.ErrTooManySignatures, "unexpected SignatureData %T", sigData)
}
}