封送指向结构异常"cannot Read or Write protected memory"的指针数组的指针数组

Question

我正在将一个本机C++库翻译成C#。原始函数分配结构的一些内存，对当前进程进行一些内存操作，并将操作后的字节返回到结构内的字节缓冲区。

结构体定义如下：

typedef struct tdMEM_SCATTER_HEADER {
DWORD magic;            
WORD version;           
WORD Future1;
ULONG64 qwA;            
DWORD cbMax;            
DWORD cb;               
PBYTE pb;             
PVOID pvReserved1;      
PVOID pvReserved2;      
PVOID Future2[8];
} MEM_SCATTER_HEADER, *PMEM_SCATTER_HEADER, **PPMEM_SCATTER_HEADER;

原始功能定义如下：

DWORD Scatter(_Inout_ PPMEM_SCATTER_HEADER ppMEMs, _In_ DWORD count);

分配顺序为

pbBuffer = LocalAlloc(0, count * (sizeof(PMEM_SCATTER_HEADER) + sizeof(MEM_SCATTER_HEADER) + 0x1000));
ZeroMemory(pbBuffer, count * (sizeof(PMEM_SCATTER_HEADER) + sizeof(MEM_SCATTER_HEADER)));
for(i = 0; i < cMEMs; i++) {
pMEM->pb = pbData + ((QWORD)i << 12); // Allocating return bytes buffer.
}

以下是我尝试过的：

结构编组：

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct MEM_SCATTER_HEADER
{
public uint magic;            
public ushort version;        
public ushort Future1;
public ulong qwA;            
public uint cbMax;            
public uint cb;                
[MarshalAs(UnmanagedType.ByValArray)]
public byte[] pb;             
public IntPtr pvReserved1;     
public IntPtr pvReserved2;                
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]
public IntPtr[] Future2;
}

内存分配：

MEM_SCATTER_HEADER[] header = new MEM_SCATTER_HEADER[count];
for (int i = 0; i < count; i++)
{
header[i].pb = new byte[0x1000];
Array.Clear(header[i].pb, 0, header[i].pb.Length); // Fill array with 0
}

DLL导入：

[DllImport("testC.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern uint Scatter(ref MEM_SCATTER_HEADER ppMems, uint count);

最后是函数调用：

uint count = Scatter(ref header, count);

我花了很长时间调试是错误地封送数据，还是必须手动封送才能消除函数调用时出现的异常："试图读取或写入受保护的内存。这通常表明其他内存已损坏。"。

Answer 1

初始分配并没有将其分配的所有内存归零，而且看起来不太好。就好像代码在做：

int bigchunk = sizeof(PMEM_SCATTER_HEADER) + sizeof(MEM_SCATTER_HEADER) + 0x1000;
int smallchunk = sizeof(PMEM_SCATTER_HEADER) + sizeof(MEM_SCATTER_HEADER);
pBuffer = LocalAlloc(0, count * bigchunk);
ZeroMemory(pBuffer, count * smallchunk);

这有关系吗？