Merge pull request #1182 from ethereum/inline-assembly-magic-variables

Disallow magic variables in inline assembly

Changelog.md

@@ -2,16 +2,18 @@
 
 Features:
 
- * Inline assembly: support both `sucide` and `selfdestruct` opcodes
-   (note: `suicide` is deprecated)
- * Include `keccak256()` as an alias to `sha3()`
+ * Inline assembly: support both ``suicide`` and ``selfdestruct`` opcodes
+   (note: ``suicide`` is deprecated).
+ * Include ``keccak256()`` as an alias to ``sha3()``.
 
 Bugfixes:
- * Disallow unknown options in `solc`
+ * Disallow unknown options in ``solc``.
  * Proper type checking for bound functions.
- * Code Generator: expect zero stack increase after `super` as an expression
- * Inline assembly: support the `address` opcode
+ * Code Generator: expect zero stack increase after `super` as an expression.
+ * Inline assembly: support the ``address`` opcode.
  * Inline assembly: fix parsing of assignment after a label.
+ * Inline assembly: external variables of unsupported type (such as ``this``, ``super``, etc.)
+   are properly detected as unusable.
 
 ### 0.4.2 (2016-09-17)
 

libsolidity/analysis/TypeChecker.cpp

@@ -609,6 +609,8 @@ bool TypeChecker::visit(InlineAssembly const& _inlineAssembly)
 					return false;
 				pushes = 1;
 			}
+			else
+				return false;
 			for (unsigned i = 0; i < pushes; ++i)
 				_assembly.append(u256(0)); // just to verify the stack height
 		}

test/libsolidity/InlineAssembly.cpp

@@ -162,6 +162,13 @@ BOOST_AUTO_TEST_CASE(assignment_after_tag)
 	BOOST_CHECK(successParse("{ let x := 1 { tag: =: x } }"));
 }
 
+BOOST_AUTO_TEST_CASE(magic_variables)
+{
+	BOOST_CHECK(!successAssemble("{ this }"));
+	BOOST_CHECK(!successAssemble("{ ecrecover }"));
+	BOOST_CHECK(successAssemble("{ let ecrecover := 1 ecrecover }"));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }