feat: EIP191 sign mode (backport #11533)

CHANGELOG.md

@@ -39,6 +39,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Features
 
+* (tx) [#\11533](https://github.com/cosmos/cosmos-sdk/pull/11533) Register [`EIP191`](https://eips.ethereum.org/EIPS/eip-191) as an available `SignMode` for chains to use.
 * [\#11430](https://github.com/cosmos/cosmos-sdk/pull/11430) Introduce a new `grpc-only` flag, such that when enabled, will start the node in a query-only mode. Note, gRPC MUST be enabled with this flag.
 * (x/upgrade) [\#11116](https://github.com/cosmos/cosmos-sdk/pull/11116) `MsgSoftwareUpgrade` and  has been added to support v1beta2 msgs-based gov proposals.
 * (x/bank) [\#11417](https://github.com/cosmos/cosmos-sdk/pull/11417) Introduce a new `SpendableBalances` gRPC query that retrieves an account's total (paginated) spendable balances.

client/cmd.go

@@ -274,7 +274,7 @@ func readTxCommandFlags(clientCtx Context, flagSet *pflag.FlagSet) (Context, err
 				clientCtx = clientCtx.WithOutputFormat("json")
 			}
 
-			// If the user didn't explicity set a --sign-mode flag, use
+			// If the user didn't explicitly set a --sign-mode flag, use
 			// DIRECT_AUX by default.
 			if clientCtx.SignModeStr == "" || !flagSet.Changed(flags.FlagSignMode) {
 				clientCtx = clientCtx.WithSignModeStr(flags.SignModeDirectAux)

client/flags/flags.go

@@ -37,6 +37,8 @@ const (
 	SignModeLegacyAminoJSON = "amino-json"
 	// SignModeDirectAux is the value of the --sign-mode flag for SIGN_MODE_DIRECT_AUX
 	SignModeDirectAux = "direct-aux"
+	// SignModeEIP191 is the value of the --sign-mode flag for SIGN_MODE_EIP_191
+	SignModeEIP191 = "eip-191"
 )
 
 // List of CLI flags

client/tx/factory.go

@@ -51,6 +51,8 @@ func NewFactoryCLI(clientCtx client.Context, flagSet *pflag.FlagSet) Factory {
 		signMode = signing.SignMode_SIGN_MODE_LEGACY_AMINO_JSON
 	case flags.SignModeDirectAux:
 		signMode = signing.SignMode_SIGN_MODE_DIRECT_AUX
+	case flags.SignModeEIP191:
+		signMode = signing.SignMode_SIGN_MODE_EIP_191
 	}
 
 	accNum, _ := flagSet.GetUint64(flags.FlagAccountNumber)

proto/cosmos/tx/signing/v1beta1/signing.proto

@@ -39,6 +39,18 @@ enum SignMode {
   // SIGN_MODE_LEGACY_AMINO_JSON is a backwards compatibility mode which uses
   // Amino JSON and will be removed in the future.
   SIGN_MODE_LEGACY_AMINO_JSON = 127;
+
+  // SIGN_MODE_EIP_191 specifies the sign mode for EIP 191 signing on the Cosmos
+  // SDK. Ref: https://eips.ethereum.org/EIPS/eip-191
+  // 
+  // Currently, SIGN_MODE_EIP_191 is registered as a SignMode enum variant,
+  // but is not implemented on the SDK by default. To enable EIP-191, you need
+  // to pass a custom `TxConfig` that has an implementation of
+  // `SignModeHandler` for EIP-191. The SDK may decide to fully support
+  // EIP-191 in the future.
+  //
+  // Since: cosmos-sdk 0.45.2
+  SIGN_MODE_EIP_191 = 191;
 }
 
 // SignatureDescriptors wraps multiple SignatureDescriptor's.

x/auth/tx/config.go

@@ -23,9 +23,16 @@ type config struct {
 
 // NewTxConfig returns a new protobuf TxConfig using the provided ProtoCodec and sign modes. The
 // first enabled sign mode will become the default sign mode.
+// NOTE: Use NewTxConfigWithHandler to provide a custom signing handler in case the sign mode
+// is not supported by default (eg: SignMode_SIGN_MODE_EIP_191).
 func NewTxConfig(protoCodec codec.ProtoCodecMarshaler, enabledSignModes []signingtypes.SignMode) client.TxConfig {
+	return NewTxConfigWithHandler(protoCodec, makeSignModeHandler(enabledSignModes))
+}
+
+// NewTxConfig returns a new protobuf TxConfig using the provided ProtoCodec and signing handler.
+func NewTxConfigWithHandler(protoCodec codec.ProtoCodecMarshaler, handler signing.SignModeHandler) client.TxConfig {
 	return &config{
-		handler:     makeSignModeHandler(enabledSignModes),
+		handler:     handler,
 		decoder:     DefaultTxDecoder(protoCodec),
 		encoder:     DefaultTxEncoder(),
 		jsonDecoder: DefaultJSONTxDecoder(protoCodec),