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Simple size check for old ABI decoder.

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This commit is contained in:
chriseth 2017-12-13 17:23:37 +01:00 committed by Alex Beregszaszi
parent 2cdf44f65c
commit 32c94f5059
3 changed files with 97 additions and 32 deletions
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117
libsolidity/codegen/CompilerUtils.cpp
View File

@ -22,11 +22,14 @@
#include <libsolidity/codegen/CompilerUtils.h>
#include <libsolidity/ast/AST.h>
#include <libevmasm/Instruction.h>
#include <libsolidity/codegen/ArrayUtils.h>
#include <libsolidity/codegen/LValue.h>
#include <libsolidity/codegen/ABIFunctions.h>
#include <libevmasm/Instruction.h>
#include <libdevcore/Whiskers.h>
using namespace std;
namespace dev
@ -159,26 +162,37 @@ void CompilerUtils::storeInMemoryDynamic(Type const& _type, bool _padToWordBound
}
}
void CompilerUtils::abiDecode(TypePointers const& _typeParameters, bool _fromMemory)
void CompilerUtils::abiDecode(TypePointers const& _typeParameters, bool _fromMemory, bool _revertOnOutOfBounds)
{
// We do not check the calldata size, everything is zero-padded
/// Stack: <source_offset> <length>
if (m_context.experimentalFeatureActive(ExperimentalFeature::ABIEncoderV2))
{
// Use the new JULIA-based decoding function
auto stackHeightBefore = m_context.stackHeight();
abiDecodeV2(_typeParameters, _fromMemory);
solAssert(m_context.stackHeight() - stackHeightBefore == sizeOnStack(_typeParameters) - 1, "");
solAssert(m_context.stackHeight() - stackHeightBefore == sizeOnStack(_typeParameters) - 2, "");
return;
}
//@todo this does not yet support nested dynamic arrays
if (_revertOnOutOfBounds)
{
size_t encodedSize = 0;
for (auto const& t: _typeParameters)
encodedSize += t->decodingType()->calldataEncodedSize(true);
m_context.appendInlineAssembly("{ if lt(len, " + to_string(encodedSize) + ") { revert(0, 0) } }", {"len"});
}
m_context << Instruction::DUP2 << Instruction::ADD;
m_context << Instruction::SWAP1;
/// Stack: <input_end> <source_offset>
// Retain the offset pointer as base_offset, the point from which the data offsets are computed.
m_context << Instruction::DUP1;
for (TypePointer const& parameterType: _typeParameters)
{
// stack: v1 v2 ... v(k-1) base_offset current_offset
// stack: v1 v2 ... v(k-1) input_end base_offset current_offset
TypePointer type = parameterType->decodingType();
solUnimplementedAssert(type, "No decoding type found.");
if (type->category() == Type::Category::Array)
@ -198,13 +212,35 @@ void CompilerUtils::abiDecode(TypePointers const& _typeParameters, bool _fromMem
{
// compute data pointer
m_context << Instruction::DUP1 << Instruction::MLOAD;
m_context << Instruction::DUP3 << Instruction::ADD;
m_context << Instruction::SWAP2 << Instruction::SWAP1;
if (_revertOnOutOfBounds)
{
// Check that the data pointer is valid and that length times
// item size is still inside the range.
Whiskers templ(R"({
if gt(ptr, 0x100000000) { revert(0, 0) }
ptr := add(ptr, base_offset)
let array_data_start := add(ptr, 0x20)
if gt(array_data_start, input_end) { revert(0, 0) }
let array_length := mload(ptr)
if or(
gt(array_length, 0x100000000),
gt(add(array_data_start, mul(array_length, <item_size>)), input_end)
) { revert(0, 0) }
})");
templ("item_size", to_string(arrayType.isByteArray() ? 1 : arrayType.baseType()->calldataEncodedSize(true)));
m_context.appendInlineAssembly(templ.render(), {"input_end", "base_offset", "offset", "ptr"});
}
else
m_context << Instruction::DUP3 << Instruction::ADD;
// stack: v1 v2 ... v(k-1) input_end base_offset current_offset v(k)
moveIntoStack(3);
m_context << u256(0x20) << Instruction::ADD;
}
else
{
m_context << Instruction::SWAP1 << Instruction::DUP2;
// Size has already been checked for this one.
moveIntoStack(2);
m_context << Instruction::DUP3;
m_context << u256(arrayType.calldataEncodedSize(true)) << Instruction::ADD;
}
}
@ -216,24 +252,43 @@ void CompilerUtils::abiDecode(TypePointers const& _typeParameters, bool _fromMem
{
// put on stack: data_pointer length
loadFromMemoryDynamic(IntegerType(256), !_fromMemory);
// stack: base_offset data_offset next_pointer
m_context << Instruction::SWAP1 << Instruction::DUP3 << Instruction::ADD;
// stack: base_offset next_pointer data_pointer
m_context << Instruction::SWAP1;
// stack: input_end base_offset next_pointer data_offset
if (_revertOnOutOfBounds)
m_context.appendInlineAssembly("{ if gt(data_offset, 0x100000000) { revert(0, 0) } }", {"data_offset"});
m_context << Instruction::DUP3 << Instruction::ADD;
// stack: input_end base_offset next_pointer array_head_ptr
if (_revertOnOutOfBounds)
m_context.appendInlineAssembly(
"{ if gt(add(array_head_ptr, 0x20), input_end) { revert(0, 0) } }",
{"input_end", "base_offset", "next_ptr", "array_head_ptr"}
);
// retrieve length
loadFromMemoryDynamic(IntegerType(256), !_fromMemory, true);
// stack: base_offset next_pointer length data_pointer
// stack: input_end base_offset next_pointer array_length data_pointer
m_context << Instruction::SWAP2;
// stack: base_offset data_pointer length next_pointer
// stack: input_end base_offset data_pointer array_length next_pointer
if (_revertOnOutOfBounds)
{
unsigned itemSize = arrayType.isByteArray() ? 1 : arrayType.baseType()->calldataEncodedSize(true);
m_context.appendInlineAssembly(R"({
if or(
gt(array_length, 0x100000000),
gt(add(data_ptr, mul(array_length, )" + to_string(itemSize) + R"()), input_end)
) { revert(0, 0) }
})", {"input_end", "base_offset", "data_ptr", "array_length", "next_ptr"});
}
}
else
{
// leave the pointer on the stack
// size has already been checked
// stack: input_end base_offset data_offset
m_context << Instruction::DUP1;
m_context << u256(calldataType->calldataEncodedSize()) << Instruction::ADD;
}
if (arrayType.location() == DataLocation::Memory)
{
// stack: base_offset calldata_ref [length] next_calldata
// stack: input_end base_offset calldata_ref [length] next_calldata
// copy to memory
// move calldata type up again
moveIntoStack(calldataType->sizeOnStack());
@ -241,21 +296,27 @@ void CompilerUtils::abiDecode(TypePointers const& _typeParameters, bool _fromMem
// fetch next pointer again
moveToStackTop(arrayType.sizeOnStack());
}
// move base_offset up
moveToStackTop(1 + arrayType.sizeOnStack());
// move input_end up
// stack: input_end base_offset calldata_ref [length] next_calldata
moveToStackTop(2 + arrayType.sizeOnStack());
m_context << Instruction::SWAP1;
// stack: base_offset calldata_ref [length] input_end next_calldata
moveToStackTop(2 + arrayType.sizeOnStack());
m_context << Instruction::SWAP1;
// stack: calldata_ref [length] input_end base_offset next_calldata
}
}
else
{
solAssert(!type->isDynamicallySized(), "Unknown dynamically sized type: " + type->toString());
loadFromMemoryDynamic(*type, !_fromMemory, true);
moveToStackTop(1 + type->sizeOnStack());
m_context << Instruction::SWAP1;
// stack: v1 v2 ... v(k-1) input_end base_offset v(k) mem_offset
moveToStackTop(1, type->sizeOnStack());
moveIntoStack(3, type->sizeOnStack());
}
// stack: v1 v2 ... v(k-1) v(k) base_offset mem_offset
// stack: v1 v2 ... v(k-1) v(k) input_end base_offset next_offset
}
m_context << Instruction::POP << Instruction::POP;
popStackSlots(3);
}
void CompilerUtils::encodeToMemory(
@ -420,15 +481,13 @@ void CompilerUtils::abiEncodeV2(
void CompilerUtils::abiDecodeV2(TypePointers const& _parameterTypes, bool _fromMemory)
{
// stack: <source_offset>
// stack: <source_offset> <length> [stack top]
auto ret = m_context.pushNewTag();
moveIntoStack(2);
// stack: <return tag> <source_offset> <length> [stack top]
m_context << Instruction::DUP2 << Instruction::ADD;
m_context << Instruction::SWAP1;
if (_fromMemory)
// TODO pass correct size for the memory case
m_context << (u256(1) << 63);
else
m_context << Instruction::CALLDATASIZE;
m_context << Instruction::SWAP1;
// stack: <return tag> <end> <start>
string decoderName = m_context.abiFunctions().tupleDecoder(_parameterTypes, _fromMemory);
m_context.appendJumpTo(m_context.namedTag(decoderName));
m_context.adjustStackOffset(int(sizeOnStack(_parameterTypes)) - 3);

10
libsolidity/codegen/CompilerUtils.h
View File

@ -90,8 +90,12 @@ public:
/// Creates code that unpacks the arguments according to their types specified by a vector of TypePointers.
/// From memory if @a _fromMemory is true, otherwise from call data.
/// Expects source offset on the stack, which is removed.
void abiDecode(TypePointers const& _typeParameters, bool _fromMemory = false);
/// Calls revert if @a _revertOnOutOfBounds is true and the supplied size is shorter
/// than the static data requirements or if dynamic data pointers reach outside of the
/// area. Also has a hard cap of 0x100000000 for any given length/offset field.
/// Stack pre: <source_offset> <length>
/// Stack post: <value0> <value1> ... <valuen>
void abiDecode(TypePointers const& _typeParameters, bool _fromMemory = false, bool _revertOnOutOfBounds = false);
/// Copies values (of types @a _givenTypes) given on the stack to a location in memory given
/// at the stack top, encoding them according to the ABI as the given types @a _targetTypes.
@ -154,7 +158,7 @@ public:
/// Decodes data from ABI encoding into internal encoding. If @a _fromMemory is set to true,
/// the data is taken from memory instead of from calldata.
/// Can allocate memory.
/// Stack pre: <source_offset>
/// Stack pre: <source_offset> <length>
/// Stack post: <value0> <value1> ... <valuen>
void abiDecodeV2(TypePointers const& _parameterTypes, bool _fromMemory = false);

2
libsolidity/codegen/ContractCompiler.cpp
View File

@ -278,6 +278,7 @@ void ContractCompiler::appendConstructor(FunctionDefinition const& _constructor)
m_context.appendProgramSize();
m_context << Instruction::DUP4 << Instruction::CODECOPY;
m_context << Instruction::DUP2 << Instruction::ADD;
m_context << Instruction::DUP1;
CompilerUtils(m_context).storeFreeMemoryPointer();
// stack: <memptr>
CompilerUtils(m_context).abiDecode(FunctionType(_constructor).parameterTypes(), true);
@ -367,6 +368,7 @@ void ContractCompiler::appendFunctionSelector(ContractDefinition const& _contrac
{
// Parameter for calldataUnpacker
m_context << CompilerUtils::dataStartOffset;
m_context << Instruction::DUP1 << Instruction::CALLDATASIZE << Instruction::SUB;
CompilerUtils(m_context).abiDecode(functionType->parameterTypes());
}
m_context.appendJumpTo(m_context.functionEntryLabel(functionType->declaration()));