Disallow complex expressions as argument of abi.decode

Changelog.md

@@ -12,6 +12,7 @@ Compiler Features:
  * SMTChecker: Add ``--model-checker-print-query`` CLI option and ``settings.modelChecker.printQuery`` JSON option to output the SMTChecker queries in the SMTLIB2 format. This requires using `smtlib2` solver only.
  * Standard JSON Interface: Add ``ast`` file-level output for Yul input.
  * Standard JSON Interface: Add ``irAst`` and ``irOptimizedAst`` contract-level outputs for Solidity input, providing AST in compact JSON format for IR and optimized IR.
+ * Type Checker: Disallow complex expressions such ternary conditionals and nested tuples as arguments for ``abi.decode``.
  * Yul Optimizer: Stack-to-memory mover is now enabled by default whenever possible for via IR code generation and pure Yul compilation.
 
 

libsolidity/analysis/TypeChecker.cpp

@@ -249,7 +249,23 @@ TypePointers TypeChecker::typeCheckABIDecodeAndRetrieveReturnType(FunctionCall c
  for (auto const& typeArgument: tupleExpression->components())
  {
  solAssert(typeArgument, "");
- if (TypeType const* argTypeType = dynamic_cast<TypeType const*>(type(*typeArgument)))
+ if (
+ !dynamic_cast<ElementaryTypeNameExpression const*>(typeArgument.get()) &&
+ !dynamic_cast<Identifier const*>(typeArgument.get()) &&
+ !dynamic_cast<IndexAccess const*>(typeArgument.get()) &&
+ !dynamic_cast<MemberAccess const*>(typeArgument.get())
+ )
+ {
+
+ m_errorReporter.typeError(
+ 5901_error,
+ typeArgument->location(),
+ "Expression is not allowed as argument here. Argument must be "
+ "a built-in type name, an user-defined type name or an array of those."
+ );
+ components.push_back(TypeProvider::emptyTuple());
+ }
+ else if (TypeType const* argTypeType = dynamic_cast<TypeType const*>(type(*typeArgument)))
  {
  Type const* actualType = argTypeType->actualType();
  solAssert(actualType, "");

test/libsolidity/syntaxTests/nameAndTypeResolution/584_abi_decode_with_tuple_of_other_than_types.sol

@@ -2,4 +2,4 @@ contract C {
  function f() pure public { abi.decode("", (0)); }
 }
 // ----
-// TypeError 1039: (60-61): Argument has to be a type name.
+// TypeError 5901: (60-61): Expression is not allowed as argument here. Argument must be a built-in type name, an user-defined type name or an array of those.

test/libsolidity/syntaxTests/specialFunctions/abidecode/abi_decode_array_of_tuples.sol

@@ -0,0 +1,15 @@
+contract C {
+ function f() pure public {
+ abi.decode("", ((uint)[2]));
+ abi.decode("", ((uint)[]));
+ abi.decode("", ((uint)[][3]));
+ abi.decode("", ((uint)[4][]));
+ abi.decode("", ((uint)[5][6]));
+ }
+}
+// ----
+// Warning 6133: (52-79): Statement has no effect.
+// Warning 6133: (89-115): Statement has no effect.
+// Warning 6133: (125-154): Statement has no effect.
+// Warning 6133: (164-193): Statement has no effect.
+// Warning 6133: (203-233): Statement has no effect.

test/libsolidity/syntaxTests/specialFunctions/abidecode/abi_decode_enum.sol

@@ -0,0 +1,8 @@
+contract C {
+ enum Color { red, green, blue }
+ function f() pure public {
+ abi.decode("", (Color));
+ }
+}
+// ----
+// Warning 6133: (88-111): Statement has no effect.

test/libsolidity/syntaxTests/specialFunctions/abidecode/abi_decode_invalid_argument_indexed_array_literal.sol

@@ -0,0 +1,7 @@
+contract C {
+ function f() pure public {
+ abi.decode("", ([uint][2]));
+ }
+}
+// ----
+// TypeError 9656: (68-74): Unable to deduce nameable type for array elements. Try adding explicit type conversion for the first element.

test/libsolidity/syntaxTests/specialFunctions/abidecode/abi_decode_invalid_argument_ternary_condition_expression.sol

@@ -0,0 +1,10 @@
+contract C {
+ function f() pure public {
+ int x;
+ abi.decode("", ((x = 1) > 0 ? int : int));
+ abi.decode("", (true ? uint : uint));
+ }
+}
+// ----
+// TypeError 5901: (83-106): Expression is not allowed as argument here. Argument must be a built-in type name, an user-defined type name or an array of those.
+// TypeError 5901: (134-152): Expression is not allowed as argument here. Argument must be a built-in type name, an user-defined type name or an array of those.

test/libsolidity/syntaxTests/specialFunctions/abidecode/abi_decode_invalid_argument_tuple_type.sol

@@ -0,0 +1,9 @@
+contract C {
+ function f() pure public {
+ abi.decode("", ((uint)));
+ abi.decode("", ((uint, int)));
+ }
+}
+// ----
+// TypeError 5901: (68-74): Expression is not allowed as argument here. Argument must be a built-in type name, an user-defined type name or an array of those.
+// TypeError 5901: (102-113): Expression is not allowed as argument here. Argument must be a built-in type name, an user-defined type name or an array of those.

test/libsolidity/syntaxTests/specialFunctions/abidecode/abi_decode_member_acess.sol

@@ -0,0 +1,19 @@
+library L {
+ struct S { int a; }
+ enum State { idle, running, blocked }
+}
+
+contract D {
+ struct X { uint b; }
+ enum Color { red, green, blue }
+}
+
+contract C {
+ function f() pure public {
+ abi.decode("", (L.S));
+ abi.decode("", (L.State));
+ abi.decode("", (D.X));
+ abi.decode("", (D.Color));
+ }
+}
+// ----