fix: prevent signing from wrong key in multisig

CHANGELOG.md

@@ -71,6 +71,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (store) [\#1310](https://github.com/Finschia/finschia-sdk/pull/1310) fix app-hash mismatch if upgrade migration commit is interrupted(backport cosmos/cosmos-sdk#13530)
 * (types) [\#1313](https://github.com/Finschia/finschia-sdk/pull/1313) fix correctly coalesce coins even with repeated denominations(backport cosmos/cosmos-sdk#13265)
 * (x/crypto) [\#1316](https://github.com/Finschia/finschia-sdk/pull/1316) error if incorrect ledger public key (backport cosmos/cosmos-sdk#14460, cosmos/cosmos-sdk#19691) 
+* (x/auth) [#1319](https://github.com/Finschia/finschia-sdk/pull/1319) prevent signing from wrong key in multisig
 
 ### Removed
 

x/auth/client/cli/tx_multisign.go

@@ -413,3 +413,13 @@
 
 	return multisigInfo, nil
 }
+
+func getMultisigRecord(clientCtx client.Context, name string) (keyring.Info, error) {
+	kb := clientCtx.Keyring
+	multisigRecord, err := kb.Key(name)
+	if err != nil {
+		return nil, errors.Wrap(err, "error getting keybase multisig account")
+	}
+
+	return multisigRecord, nil
+}

x/auth/client/cli/tx_sign.go

@@ -9,7 +9,7 @@
 	"github.com/Finschia/finschia-sdk/client"
 	"github.com/Finschia/finschia-sdk/client/flags"
 	"github.com/Finschia/finschia-sdk/client/tx"
-	sdk "github.com/Finschia/finschia-sdk/types"
+	kmultisig "github.com/Finschia/finschia-sdk/crypto/keys/multisig"
 	authclient "github.com/Finschia/finschia-sdk/x/auth/client"
 )
 
@@ -258,14 +258,33 @@
 
 		overwrite, _ := f.GetBool(flagOverwrite)
 		if multisig != "" {
-			multisigAddr, err := sdk.AccAddressFromBech32(multisig)
+			// Bech32 decode error, maybe it's a name, we try to fetch from keyring
+			multisigAddr, multisigName, _, err := client.GetFromFields(txFactory.Keybase(), multisig, clientCtx.GenerateOnly)
 			if err != nil {
-				// Bech32 decode error, maybe it's a name, we try to fetch from keyring
-				multisigAddr, _, _, err = client.GetFromFields(txFactory.Keybase(), multisig, clientCtx.GenerateOnly)
-				if err != nil {
-					return fmt.Errorf("error getting account from keybase: %w", err)
+				return fmt.Errorf("error getting account from keybase: %w", err)
+			}
+			multisigkey, err := getMultisigRecord(clientCtx, multisigName)
+			if err != nil {
+				return err
+			}
+			multisigPubKey := multisigkey.GetPubKey()
+			multisigLegacyPub := multisigPubKey.(*kmultisig.LegacyAminoPubKey)
+
+			fromRecord, err := clientCtx.Keyring.Key(fromName)
+			if err != nil {
+				return fmt.Errorf("error getting account from keybase: %w", err)
+			}
+			fromPubKey := fromRecord.GetPubKey()
+
+			var found bool
+			for _, pubkey := range multisigLegacyPub.GetPubKeys() {
+				if pubkey.Equals(fromPubKey) {
+					found = true
 				}
 			}
+			if !found {
+				return fmt.Errorf("signing key is not a part of multisig key")
+			}
 			err = authclient.SignTxWithSignerAddress(
 				txF, clientCtx, multisigAddr, fromName, txBuilder, clientCtx.Offline, overwrite)
 			if err != nil {

x/auth/client/testutil/suite.go

@@ -61,6 +61,10 @@ func (s *IntegrationTestSuite) SetupSuite() {
 	account2, _, err := kb.NewMnemonic("newAccount2", keyring.English, sdk.FullFundraiserPath, keyring.DefaultBIP39Passphrase, hd.Secp256k1)
 	s.Require().NoError(err)
 
+	// Create a dummy account for testing purpose
+	_, _, err = kb.NewMnemonic("dummyAccount", keyring.English, sdk.FullFundraiserPath, keyring.DefaultBIP39Passphrase, hd.Secp256k1)
+	s.Require().NoError(err)
+
 	multi := kmultisig.NewLegacyAminoPubKey(2, []cryptotypes.PubKey{account1.GetPubKey(), account2.GetPubKey()})
 	_, err = kb.SaveMultisig("multi", multi)
 	s.Require().NoError(err)
@@ -789,6 +793,10 @@ func (s *IntegrationTestSuite) TestCLIMultisignSortSignatures() {
 	multisigInfo, err := val1.ClientCtx.Keyring.Key("multi")
 	s.Require().NoError(err)
 
+	// Generate dummy account which is not a part of multisig.
+	dummyAcc, err := val1.ClientCtx.Keyring.Key("dummyAccount")
+	s.Require().NoError(err)
+
 	resp, err := bankcli.QueryBalancesExec(val1.ClientCtx, multisigInfo.GetAddress())
 	s.Require().NoError(err)
 
@@ -841,12 +849,18 @@ func (s *IntegrationTestSuite) TestCLIMultisignSortSignatures() {
 
 	sign1File := testutil.WriteToNewTempFile(s.T(), account1Signature.String())
 
-	// Sign with account1
+	// Sign with account2
 	account2Signature, err := TxSignExec(val1.ClientCtx, account2.GetAddress(), multiGeneratedTxFile.Name(), "--multisig", multisigInfo.GetAddress().String())
 	s.Require().NoError(err)
 
 	sign2File := testutil.WriteToNewTempFile(s.T(), account2Signature.String())
 
+	// Sign with dummy account
+	dummyAddr := dummyAcc.GetAddress()
+	_, err = TxSignExec(val1.ClientCtx, dummyAddr, multiGeneratedTxFile.Name(), "--multisig", multisigInfo.GetAddress().String())
+	s.Require().Error(err)
+	s.Require().Contains(err.Error(), "signing key is not a part of multisig key")
+
 	multiSigWith2Signatures, err := TxMultiSignExec(val1.ClientCtx, multisigInfo.GetName(), multiGeneratedTxFile.Name(), sign1File.Name(), sign2File.Name())
 	s.Require().NoError(err)
 
@@ -901,7 +915,7 @@ func (s *IntegrationTestSuite) TestSignWithMultisig() {
 	// as the main point of this test is to test the `--multisig` flag with an address
 	// that is not in the keyring.
 	_, err = TxSignExec(val1.ClientCtx, addr1, multiGeneratedTx2File.Name(), "--multisig", multisigAddr.String())
-	s.Require().Contains(err.Error(), "tx intended signer does not match the given signer")
+	s.Require().Contains(err.Error(), "error getting account from keybase")
 }
 
 func (s *IntegrationTestSuite) TestCLIMultisign() {