fix(evm-precompiles): add assertNumArgs validation (#2060)

CHANGELOG.md

@@ -125,6 +125,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - [#2045](https://github.com/NibiruChain/nibiru/pull/2045) - test(evm): backend tests with test network and real txs
 - [#2053](https://github.com/NibiruChain/nibiru/pull/2053) - refactor(evm): converted untyped event to typed and cleaned up
 - [#2054](https://github.com/NibiruChain/nibiru/pull/2054) - feat(evm-precompile): Precompile for one-way EVM calls to invoke/execute Wasm contracts. 
+- [#2060](https://github.com/NibiruChain/nibiru/pull/2060) - fix(evm-precompiles): add assertNumArgs validation
 
 #### Dapp modules: perp, spot, oracle, etc
 

x/evm/precompile/errors.go

@@ -43,3 +43,13 @@ func assertContractQuery(contract *vm.Contract) error {
 
 	return nil
 }
+
+// assertNumArgs checks if the number of provided arguments matches the expected
+// count. If lenArgs does not equal wantArgsLen, it returns an error describing
+// the mismatch between expected and actual argument counts.
+func assertNumArgs(lenArgs, wantArgsLen int) error {
+	if lenArgs != wantArgsLen {
+		return fmt.Errorf("expected %d arguments but got %d", wantArgsLen, lenArgs)
+	}
+	return nil
+}

x/evm/precompile/funtoken.go

@@ -205,9 +205,10 @@ func (p precompileFunToken) decomposeBankSendArgs(args []any) (
 	to string,
 	err error,
 ) {
-	// Note: The number of arguments is valiated before this function is called
-	// during "DecomposeInput". DecomposeInput calls "method.Inputs.Unpack",
-	// which validates against the the structure of the precompile's ABI.
+	if e := assertNumArgs(len(args), 3); e != nil {
+		err = e
+		return
+	}
 
 	erc20, ok := args[0].(gethcommon.Address)
 	if !ok {

x/evm/precompile/wasm.go

@@ -355,9 +355,10 @@ func (p precompileWasm) queryRaw(
 		return bz, err
 	}
 
-	// Note: The number of arguments is valiated before this function is called
-	// during "DecomposeInput". DecomposeInput calls "method.Inputs.Unpack",
-	// which validates against the the structure of the precompile's ABI.
+	if e := assertNumArgs(len(args), 2); e != nil {
+		err = e
+		return
+	}
 
 	argIdx := 0
 	wasmContract, e := parseContractAddrArg(args[argIdx])

x/evm/precompile/wasm_parse.go

@@ -84,9 +84,10 @@ func (p precompileWasm) parseInstantiateArgs(args []any, sender string) (
 	txMsg wasm.MsgInstantiateContract,
 	err error,
 ) {
-	// Note: The number of arguments is valiated before this function is called
-	// during "DecomposeInput". DecomposeInput calls "method.Inputs.Unpack",
-	// which validates against the the structure of the precompile's ABI.
+	if e := assertNumArgs(len(args), 5); e != nil {
+		err = e
+		return
+	}
 
 	argIdx := 0
 	admin, ok := args[argIdx].(string)
@@ -142,9 +143,10 @@ func (p precompileWasm) parseExecuteArgs(args []any) (
 	funds sdk.Coins,
 	err error,
 ) {
-	// Note: The number of arguments is valiated before this function is called
-	// during "DecomposeInput". DecomposeInput calls "method.Inputs.Unpack",
-	// which validates against the the structure of the precompile's ABI.
+	if e := assertNumArgs(len(args), 3); e != nil {
+		err = e
+		return
+	}
 
 	argIdx := 0
 	contractAddrStr, ok := args[argIdx].(string)
@@ -187,9 +189,10 @@ func (p precompileWasm) parseQueryArgs(args []any) (
 	req wasm.RawContractMessage,
 	err error,
 ) {
-	// Note: The number of arguments is valiated before this function is called
-	// during "DecomposeInput". DecomposeInput calls "method.Inputs.Unpack",
-	// which validates against the the structure of the precompile's ABI.
+	if e := assertNumArgs(len(args), 2); e != nil {
+		err = e
+		return
+	}
 
 	argsIdx := 0
 	wasmContract, e := parseContractAddrArg(args[argsIdx])
@@ -220,9 +223,10 @@ func (p precompileWasm) parseExecuteMultiArgs(args []any) (
 	},
 	err error,
 ) {
-	// Note: The number of arguments is valiated before this function is called
-	// during "DecomposeInput". DecomposeInput calls "method.Inputs.Unpack",
-	// which validates against the the structure of the precompile's ABI.
+	if e := assertNumArgs(len(args), 1); e != nil {
+		err = e
+		return
+	}
 
 	arg := args[0]
 	execMsgs, ok := arg.([]struct {