c++/clr StructureToPtr Stack buffer overflow - c++-cli

Question

as I have asked in this question c++/clr StructureToPtr exit application without any exception or error
and thanks to the comment, I found out the exit code is -1073740791, which means Stack buffer overflow / overrun. So let me post my two structures,
[StructLayout(LayoutKind::Sequential)]
public ref struct ThostFtdcInputOrderField
{
[MarshalAs(UnmanagedType::ByValTStr, SizeConst = 11)]
String^ BrokerID;
[MarshalAs(UnmanagedType::ByValTStr, SizeConst = 13)]
String^ InvestorID;
[MarshalAs(UnmanagedType::ByValTStr, SizeConst = 31)]
String^ InstrumentID;
[MarshalAs(UnmanagedType::ByValTStr, SizeConst = 13)]
String^ OrderRef;
[MarshalAs(UnmanagedType::ByValTStr, SizeConst = 16)]
String^ UserID;
EnumOrderPriceTypeType OrderPriceType;
EnumDirectionType Direction;
EnumOffsetFlagType CombOffsetFlag;
EnumOffsetFlagType CombHedgeFlag;
double LimitPrice;
int VolumeTotalOriginal;
EnumTimeConditionType TimeCondition;
[MarshalAs(UnmanagedType::ByValTStr, SizeConst = 9)]
String^ GTDDate;
EnumVolumeConditionType VolumeCondition;
int MinVolume;
EnumContingentConditionType ContingentCondition;
double StopPrice;
EnumForceCloseReasonType ForceCloseReason;
int IsAutoSuspend;
[MarshalAs(UnmanagedType::ByValTStr, SizeConst = 21)]
String^ BusinessUnit;
int RequestID;
int UserForceClose;
};
The Enums
public enum struct EnumOrderPriceTypeType
{
AnyPrice = (Byte)'1',
LimitPrice = (Byte)'2',
BestPrice = (Byte)'3',
LastPrice = (Byte)'4',
LastPricePlusOneTicks = (Byte)'5',
LastPricePlusTwoTicks = (Byte)'6',
LastPricePlusThreeTicks = (Byte)'7',
AskPrice1 = (Byte)'8',
AskPrice1PlusOneTicks = (Byte)'9',
AskPrice1PlusTwoTicks = (Byte)'A',
AskPrice1PlusThreeTicks = (Byte)'B',
BidPrice1 = (Byte)'C',
BidPrice1PlusOneTicks = (Byte)'D',
BidPrice1PlusTwoTicks = (Byte)'E',
BidPrice1PlusThreeTicks = (Byte)'F'
};
public enum struct EnumDirectionType
{
Buy = (Byte)'0',
Sell = (Byte)'1'
};
public enum struct EnumOffsetFlagType
{
Open = (Byte)'0',
Close = (Byte)'1',
ForceClose = (Byte)'2',
CloseToday = (Byte)'3',
CloseYesterday = (Byte)'4',
ForceOff = (Byte)'5',
LocalForceClose = (Byte)'6'
};
public enum struct EnumTimeConditionType
{
IOC = (Byte)'1',
GFS = (Byte)'2',
GFD = (Byte)'3',
GTD = (Byte)'4',
GTC = (Byte)'5',
GFA = (Byte)'6'
};
public enum struct EnumVolumeConditionType
{
AV = (Byte)'1',
MV = (Byte)'2',
CV = (Byte)'3'
};
public enum struct EnumContingentConditionType
{
Immediately = (Byte)'1',
Touch = (Byte)'2',
TouchProfit = (Byte)'3',
ParkedOrder = (Byte)'4',
LastPriceGreaterThanStopPrice = (Byte)'5',
LastPriceGreaterEqualStopPrice = (Byte)'6',
LastPriceLesserThanStopPrice = (Byte)'7',
LastPriceLesserEqualStopPrice = (Byte)'8',
AskPriceGreaterThanStopPrice = (Byte)'9',
AskPriceGreaterEqualStopPrice = (Byte)'A',
AskPriceLesserThanStopPrice = (Byte)'B',
AskPriceLesserEqualStopPrice = (Byte)'C',
BidPriceGreaterThanStopPrice = (Byte)'D',
BidPriceGreaterEqualStopPrice = (Byte)'E',
BidPriceLesserThanStopPrice = (Byte)'F',
BidPriceLesserEqualStopPrice = (Byte)'H'
};
public enum struct EnumForceCloseReasonType
{
NotForceClose = (Byte)'0',
LackDeposit = (Byte)'1',
ClientOverPositionLimit = (Byte)'2',
MemberOverPositionLimit = (Byte)'3',
NotMultiple = (Byte)'4',
Violation = (Byte)'5',
Other = (Byte)'6',
PersonDeliv = (Byte)'7'
};
The C++ struct
struct CThostFtdcInputOrderField
{
TThostFtdcBrokerIDType BrokerID;
TThostFtdcInvestorIDType InvestorID;
TThostFtdcInstrumentIDType InstrumentID;
TThostFtdcOrderRefType OrderRef;
TThostFtdcUserIDType UserID;
TThostFtdcOrderPriceTypeType OrderPriceType;
TThostFtdcDirectionType Direction;
TThostFtdcCombOffsetFlagType CombOffsetFlag;
TThostFtdcCombHedgeFlagType CombHedgeFlag;
TThostFtdcPriceType LimitPrice;
TThostFtdcVolumeType VolumeTotalOriginal;
TThostFtdcTimeConditionType TimeCondition;
TThostFtdcDateType GTDDate;
TThostFtdcVolumeConditionType VolumeCondition;
TThostFtdcVolumeType MinVolume;
TThostFtdcContingentConditionType ContingentCondition;
TThostFtdcPriceType StopPrice;
TThostFtdcForceCloseReasonType ForceCloseReason;
TThostFtdcBoolType IsAutoSuspend;
TThostFtdcBusinessUnitType BusinessUnit;
TThostFtdcRequestIDType RequestID;
TThostFtdcBoolType UserForceClose;
};
The types
typedef char TThostFtdcBrokerIDType[11];
typedef char TThostFtdcInvestorIDType[13];
typedef char TThostFtdcInstrumentIDType[31];
typedef char TThostFtdcOrderRefType[13];
typedef char TThostFtdcUserIDType[16];
typedef char TThostFtdcOrderPriceTypeType;
typedef char TThostFtdcDirectionType;
typedef char TThostFtdcCombOffsetFlagType[5];
typedef char TThostFtdcCombHedgeFlagType[5];
typedef double TThostFtdcPriceType;
typedef int TThostFtdcVolumeType;
typedef char TThostFtdcTimeConditionType;
typedef char TThostFtdcDateType[9];
typedef char TThostFtdcVolumeConditionType;
typedef char TThostFtdcContingentConditionType;
typedef char TThostFtdcForceCloseReasonType;.
typedef int TThostFtdcBoolType;
typedef char TThostFtdcBusinessUnitType[21];
typedef int TThostFtdcRequestIDType;
typedef int TThostFtdcBoolType;
As I dont know much of c++, so I have present the whole demo I was given. The demo calls this function to do the transform,
class MNConv
{
public:
/// Native to Managed
static M N2M(N* pNative){
return safe_cast<M>(Marshal::PtrToStructure(IntPtr(pNative), M::typeid));
};
// Managed to Native
static void M2N(M managed, N* pNative){
Marshal::StructureToPtr(managed, IntPtr(pNative), true);
};
};
MNConv<ThostFtdcInputOrderField^, CThostFtdcInputOrderField>::M2N(pInputOrder, &native);
The problem is this exit with exit code is -1073740791, with no exception. I am not sure what went wrong, as the same demo actually convert a few other structure with success.

Answer 1

When you use UnmanagedType::ByValTStr you MUST also specify the encoding.
Because your C++ typedef lines all use char, not wchar_t, you need
[StructLayout(LayoutKind::Sequential, CharSet = CharSet::Ansi)]
If the marshaller incorrectly uses Unicode, it will write twice as much data for each string as it should, overflowing the buffer and corrupting nearby memory.