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Merge pull request #2679 from ethereum/delegatecall

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.delegatecall() should always return a boolean of execution status
This commit is contained in:
chriseth 2017-08-02 15:46:02 +02:00 committed by GitHub
commit bd9e91085b
6 changed files with 97 additions and 4 deletions
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1
Changelog.md
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@ -3,6 +3,7 @@
Features:
Bugfixes:
* Code Generator: ``.delegatecall()`` should always return execution outcome.
* Code Generator: Provide "new account gas" for low-level ``callcode`` and ``delegatecall``.
### 0.4.14 (2017-07-31)

8
docs/bugs.json
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@ -1,4 +1,12 @@
[
{
"name": "DelegateCallReturnValue",
"summary": "The low-level .delegatecall() does not return the execution outcome, but converts the value returned by the functioned called to a boolean instead.",
"description": "The return value of the low-level .delegatecall() function is taken from a position in memory, where the call data or the return data resides. This value is interpreted as a boolean and put onto the stack. This means if the called function returns at least 32 zero bytes, .delegatecall() returns false even if the call was successuful.",
"introduced": "0.3.0",
"fixed": "0.4.15",
"severity": "low"
},
{
"name": "ECRecoverMalformedInput",
"summary": "The ecrecover() builtin can return garbage for malformed input.",

25
docs/bugs_by_version.json
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@ -182,6 +182,7 @@
},
"0.3.0": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -198,6 +199,7 @@
},
"0.3.1": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -213,6 +215,7 @@
},
"0.3.2": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -228,6 +231,7 @@
},
"0.3.3": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -242,6 +246,7 @@
},
"0.3.4": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -256,6 +261,7 @@
},
"0.3.5": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -270,6 +276,7 @@
},
"0.3.6": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -282,6 +289,7 @@
},
"0.4.0": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -294,6 +302,7 @@
},
"0.4.1": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -306,6 +315,7 @@
},
"0.4.10": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction"
@ -314,6 +324,7 @@
},
"0.4.11": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral"
],
@ -321,22 +332,27 @@
},
"0.4.12": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput"
],
"released": "2017-07-03"
},
"0.4.13": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput"
],
"released": "2017-07-06"
},
"0.4.14": {
"bugs": [],
"bugs": [
"DelegateCallReturnValue"
],
"released": "2017-07-31"
},
"0.4.2": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -348,6 +364,7 @@
},
"0.4.3": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -358,6 +375,7 @@
},
"0.4.4": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -367,6 +385,7 @@
},
"0.4.5": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -377,6 +396,7 @@
},
"0.4.6": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction",
@ -386,6 +406,7 @@
},
"0.4.7": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction"
@ -394,6 +415,7 @@
},
"0.4.8": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction"
@ -402,6 +424,7 @@
},
"0.4.9": {
"bugs": [
"DelegateCallReturnValue",
"ECRecoverMalformedInput",
"SkipEmptyStringLiteral",
"ConstantOptimizerSubtraction"

3
docs/control-structures.rst
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@ -393,6 +393,9 @@ When exceptions happen in a sub-call, they "bubble up" (i.e. exceptions are reth
and the low-level functions ``call``, ``delegatecall`` and ``callcode`` -- those return ``false`` in case
of an exception instead of "bubbling up".
.. warning::
The low-level ``call``, ``delegatecall`` and ``callcode`` will return success if the calling account is non-existent, as part of the design of EVM. Existence must be checked prior to calling if desired.
Catching exceptions is not yet possible.
In the following example, you can see how ``require`` can be used to easily check conditions on inputs

2
libsolidity/codegen/ExpressionCompiler.cpp
View File

@ -1560,7 +1560,7 @@ void ExpressionCompiler::appendExternalFunctionCall(
utils().moveToStackTop(gasValueSize, _functionType.selfType()->sizeOnStack());
auto funKind = _functionType.kind();
bool returnSuccessCondition = funKind == FunctionType::Kind::BareCall || funKind == FunctionType::Kind::BareCallCode;
bool returnSuccessCondition = funKind == FunctionType::Kind::BareCall || funKind == FunctionType::Kind::BareCallCode || funKind == FunctionType::Kind::BareDelegateCall;
bool isCallCode = funKind == FunctionType::Kind::BareCallCode || funKind == FunctionType::Kind::CallCode;
bool isDelegateCall = funKind == FunctionType::Kind::BareDelegateCall || funKind == FunctionType::Kind::DelegateCall;

58
test/libsolidity/SolidityEndToEndTest.cpp
View File

@ -9897,6 +9897,64 @@ BOOST_AUTO_TEST_CASE(inlineasm_empty_let)
BOOST_CHECK(callContractFunction("f()") == encodeArgs(u256(0), u256(0)));
}
BOOST_AUTO_TEST_CASE(bare_call_invalid_address)
{
char const* sourceCode = R"(
contract C {
/// Calling into non-existant account is successful (creates the account)
function f() external constant returns (bool) {
return address(0x4242).call();
}
function g() external constant returns (bool) {
return address(0x4242).callcode();
}
function h() external constant returns (bool) {
return address(0x4242).delegatecall();
}
}
)";
compileAndRun(sourceCode, 0, "C");
BOOST_CHECK(callContractFunction("f()") == encodeArgs(u256(1)));
BOOST_CHECK(callContractFunction("g()") == encodeArgs(u256(1)));
BOOST_CHECK(callContractFunction("h()") == encodeArgs(u256(1)));
}
BOOST_AUTO_TEST_CASE(delegatecall_return_value)
{
char const* sourceCode = R"DELIMITER(
contract C {
uint value;
function set(uint _value) external {
value = _value;
}
function get() external constant returns (uint) {
return value;
}
function get_delegated() external constant returns (bool) {
return this.delegatecall(bytes4(sha3("get()")));
}
function assert0() external constant {
assert(value == 0);
}
function assert0_delegated() external constant returns (bool) {
return this.delegatecall(bytes4(sha3("assert0()")));
}
}
)DELIMITER";
compileAndRun(sourceCode, 0, "C");
BOOST_CHECK(callContractFunction("get()") == encodeArgs(u256(0)));
BOOST_CHECK(callContractFunction("assert0_delegated()") == encodeArgs(u256(1)));
BOOST_CHECK(callContractFunction("get_delegated()") == encodeArgs(u256(1)));
BOOST_CHECK(callContractFunction("set(uint256)", u256(1)) == encodeArgs());
BOOST_CHECK(callContractFunction("get()") == encodeArgs(u256(1)));
BOOST_CHECK(callContractFunction("assert0_delegated()") == encodeArgs(u256(0)));
BOOST_CHECK(callContractFunction("get_delegated()") == encodeArgs(u256(1)));
BOOST_CHECK(callContractFunction("set(uint256)", u256(42)) == encodeArgs());
BOOST_CHECK(callContractFunction("get()") == encodeArgs(u256(42)));
BOOST_CHECK(callContractFunction("assert0_delegated()") == encodeArgs(u256(0)));
BOOST_CHECK(callContractFunction("get_delegated()") == encodeArgs(u256(1)));
}
BOOST_AUTO_TEST_SUITE_END()
}