/// <summary>
/// Finds an available already present buffer and writes writes your own memory bytes into
/// the specified buffer, giving you back the address of said buffer. If there is no available
/// buffer, a new buffer will be automatically created.
/// </summary>
/// <param name="bytesToWrite">Individual bytes to be written onto a buffer.</param>
/// <returns>Pointer to the passed in bytes written to memory.</returns>
public static IntPtr Add(byte[] bytesToWrite)
{
// Get available buffers.
List <MemoryBuffer> buffers = GetCachedBuffers(bytesToWrite.Length);
// If there are no available buffers, create one.
if (buffers.Count < 1)
{
// Get System Allocation Granularity.
GetSystemInfo(out var systemInfo);
// Get the desired page size, that being 1 allocation granularity greater than the bytes to be written.
// 40 is an (over) estimate on the buffer header size, which cannot be properly read due string.
// Retrieves the total size of the object to be added to a buffer, and the buffer header.
int totalObjectSize = bytesToWrite.Length + Marshal.SizeOf(typeof(MemoryBufferHeader));
int desiredGranularity = (totalObjectSize / (int)systemInfo.allocationGranularity) + 1;
uint desiredBufferSize = (uint)(desiredGranularity * systemInfo.allocationGranularity);
// Create new buffer.
var memoryPageSet = Bindings.TargetProcess.GetPages();
foreach (var memoryPages in memoryPageSet)
{
// For clarity, will be optimized out by the JIT compiler.
// We have to align the starting address with the allocation granularity, it must be a multiple of it.
long pageEnd = (long)memoryPages.BaseAddress + (long)memoryPages.RegionSize;
// Place on next 64K boundary (or allocation granularity)
long firstPageBase = (((long)memoryPages.BaseAddress / systemInfo.allocationGranularity) + 1) * systemInfo.allocationGranularity;
long firstPageEnd = firstPageBase + desiredBufferSize;
long lastPageBase = ((pageEnd - desiredBufferSize) / systemInfo.allocationGranularity) * systemInfo.allocationGranularity;
long lastPageEnd = lastPageBase + desiredBufferSize;
// Check if desired buffer would fit in the free page region.
if ((uint)memoryPages.RegionSize > desiredBufferSize && memoryPages.State == PageState.Free)
{
// 1. Check if inbounds. 2. Check if new page start aligned to 64K/Granularity still fits.
if (lastPageBase > (long)memoryPages.BaseAddress)
{
MemoryBuffer buffer = new MemoryBuffer((IntPtr)lastPageBase, desiredBufferSize);
_knownBuffers.Add(buffer);
return(buffer.Add(bytesToWrite));
}
// 1. Check if inbounds. 2. Check if new page start aligned to 64K/Granularity still fits.
else if (firstPageEnd < (long)memoryPages.BaseAddress + (long)memoryPages.RegionSize)
{
MemoryBuffer buffer = new MemoryBuffer((IntPtr)firstPageBase, desiredBufferSize);
_knownBuffers.Add(buffer);
return(buffer.Add(bytesToWrite));
}
}
}
// Probably out of memory.
return(IntPtr.Zero);
}
else
{
return(buffers[0].Add(bytesToWrite));
}
}
/// <summary>
/// See <see cref="Add(byte[])"/> for details. Intended to use for X64 assembly purely.
/// Adds the specified byte contents into a buffer in 32bit signed (2GB) proximity to a specified target address.
/// Intended to be used in conjunction with 64bit Assembly, where 64bit immediates are not available.
/// </summary>
/// <param name="bytesToWrite">Individual bytes to be written onto a buffer.</param>
/// <param name="targetAddress">
/// The target address within which the buffer to be written to must lie in 2GB memory proximity of.
/// Specify 0 for 32bit address, else near whatever assembly code you are targeting.
/// </param>
/// <returns>Pointer to the passed in bytes written to memory.</returns>
public static unsafe IntPtr Add(byte[] bytesToWrite, IntPtr targetAddress)
{
// Get available buffers.
List <MemoryBuffer> buffers = GetCachedBuffers(bytesToWrite.Length);
// Iterate over all buffers to see if any fits the desired target.
ulong minimumAddress = (ulong)(targetAddress + -2000000000); // 2GB
ulong maximumAddress = (ulong)targetAddress + 2000000000; // 2GB
// Check in case minimum address < 0
if (minimumAddress > (ulong)targetAddress)
{
minimumAddress = 0;
}
// Find appropriate buffer, add and return.
// If buffer not found, fallback is provided below to create a new buffer.
foreach (var buffer in buffers)
{
ulong startAddress = (ulong)buffer.BaseBufferAddress;
ulong endAddress = (ulong)buffer.BaseBufferAddress + buffer.BufferHeader.BufferSize;
if (startAddress >= minimumAddress && endAddress < maximumAddress)
{
// Ensure our bytes fit to the buffer.
if (buffer.CheckItemSize(bytesToWrite.Length))
{
return(buffer.Add(bytesToWrite));
}
}
}
// If we have not returned, no buffer was found in the specified range.
// Get a list of all pages.
var memoryBasicInformation = Bindings.TargetProcess.GetPages();
// Get System Allocation Granularity.
GetSystemInfo(out var systemInfo);
// Get the desired page size, that being 1 allocation granularity greater than the bytes to be written.
int totalBytesToWrite = bytesToWrite.Length + sizeof(MemoryBufferHeader);
int desiredGranularity = (totalBytesToWrite / (int)systemInfo.allocationGranularity) + 1;
uint desiredBufferSize = (uint)(desiredGranularity * systemInfo.allocationGranularity);
// Iterate each page.
foreach (var memoryPages in memoryBasicInformation)
{
// For clarity, will be optimized out by the JIT compiler.
// We have to align the starting address with the allocation granularity, it must be a multiple of it.
ulong pageEnd = (ulong)memoryPages.BaseAddress + (ulong)memoryPages.RegionSize;
// Place on next 64K boundary (or allocation granularity)
ulong firstPageBase = (((ulong)memoryPages.BaseAddress / systemInfo.allocationGranularity) + 1) * systemInfo.allocationGranularity;
ulong firstPageEnd = firstPageBase + desiredBufferSize;
ulong lastPageBase = ((pageEnd - desiredBufferSize) / systemInfo.allocationGranularity) * systemInfo.allocationGranularity;
ulong lastPageEnd = lastPageBase + desiredBufferSize;
// Check if desired buffer would fit in the free page region.
if ((ulong)memoryPages.RegionSize > desiredBufferSize && memoryPages.State == PageState.Free)
{
// 1. Check if inbounds. 2. Check if new page start aligned to 64K/Granularity still fits.
if (lastPageBase >= minimumAddress && lastPageEnd < maximumAddress &&
lastPageBase > (ulong)memoryPages.BaseAddress)
{
MemoryBuffer buffer = new MemoryBuffer((IntPtr)lastPageBase, desiredBufferSize);
_knownBuffers.Add(buffer);
return(buffer.Add(bytesToWrite));
}
// 1. Check if inbounds. 2. Check if new page start aligned to 64K/Granularity still fits.
else if (firstPageBase >= minimumAddress && firstPageEnd < maximumAddress &&
firstPageEnd < (ulong)memoryPages.BaseAddress + (ulong)memoryPages.RegionSize)
{
MemoryBuffer buffer = new MemoryBuffer((IntPtr)firstPageBase, desiredBufferSize);
_knownBuffers.Add(buffer);
return(buffer.Add(bytesToWrite));
}
}
}
return(IntPtr.Zero);
}
