Question

我一直在尝试在Ruby中读取和编写进程内存，希望将一些旧的C ++程序转换为更动态的语言。但是我一直没有轻松过去。我已经做了一些阅读，但我找不到我的具体问题。我可能在下面有一些非常基本的错误，因为我不太确定指针管理在Ruby-ffi中是如何工作的。

无论如何，我目前安装了ffi gem并且一直在使用它来获取功能。这就是我所拥有的：

module Memory
  PROC_READ = 0x10
  PROC_WRITE = 0x20
  PROC_RW = PROC_READ | PROC_WRITE

  extend FFI::Library

  ffi_lib 'kernel32'

  # HANDLE WINAPI OpenProcess(DWORD, BOOL, DWORD)
  attach_function :open, :OpenProcess, [:uint, :bool, :uint], :pointer

  # BOOL WINAPI CloseHandle(HANDLE)
  attach_function :close, :CloseHandle, [:pointer], :bool

  # BOOL WINAPI ReadProcessMemory(HANDLE, LPCVOID, out LPVOID, SIZE_T, out SIZE_T)
  attach_function :read, :ReadProcessMemory, [:pointer, :pointer, :pointer, :int, :int], :bool

  # BOOL WINAPI WriteProcessMemory(HANDLE, LPCVOID, LPVOID, SIZE_T, out SIZE_T)
  attach_function :write, :WriteProcessMemory, [:pointer, :pointer, :pointer, :int, :int], :bool

  # DWORD WINAPI GetLastError(void)
  attach_function :error, :GetLastError, [], :uint
end

似乎当我调用Memory.open时，我得到一个正确的句柄。我不太确定，但这里是存储结果的变量的输出，以防我错了。

#<FFI::Pointer address=0x00000000000150>

这是我目前的完整代码：

# 1048 is a fixed pid currently
handle = Memory::open(Memory::PROC_RW, false, 1048)
puts "GetLastError: #{Memory::error()}"

# Address to read from
loc = 0x057C75F8

out = 0
read = 0

# Supposed to be the address of out to store the value read
val = FFI::MemoryPointer.new :uint, out

# Supposed to be a pointer to loc which holds the address to read from
addr = FFI::MemoryPointer.new :pointer, loc

res = Memory::read(handle, addr, val, 4, read)

puts "GetLastError: #{Memory::error()}"
puts "ReadProcessMemory: #{res}"
puts read
puts out

Memory::close(handle)

这打印出以下内容：

GetLastError: 0
GetLastError: 0
ReadProcessMemory: false
0
0

我知道我必须做一些根本错误的指针变量。如果我将addr更改为FFI::Pointer类型的:uint和值loc，则ReadProcessMemory会返回true，但out和read变量不会改变。

我希望这已经足够清楚了。我可以尝试澄清是否有遗漏。

Answer 1

在阅读Github上的示例页面后，我终于能够找出指针的问题：

https://github.com/ffi/ffi/wiki/Examples

具体在“带MemoryPointer的输出参数”部分下。在阅读之后，我能够将我的代码更改为以下内容：

require 'ffi'

module Memory
  PROC_READ = 0x10
  PROC_WRITE = 0x20
  PROC_RW = PROC_READ | PROC_WRITE

  extend FFI::Library

  ffi_lib 'kernel32'
  ffi_convention :stdcall

  attach_function :open, :OpenProcess, [:uint, :bool, :uint], :pointer
  attach_function :close, :CloseHandle, [:pointer], :bool
  attach_function :read, :ReadProcessMemory, [:pointer, :pointer, :pointer, :size_t, :pointer], :bool
  attach_function :write, :WriteProcessMemory, [:pointer, :pointer, :pointer, :size_t, :pointer], :bool
  attach_function :error, :GetLastError, [], :uint
end

# 1048 is a fixed pid currently
handle = Memory::open(Memory::PROC_RW, false, 1048)
puts "GetLastError: #{Memory::error()}"

# Output parameters for ReadProcessMemory
out = FFI::MemoryPointer.new :pointer
read = FFI::MemoryPointer.new :pointer

# Pointer holding the location to read from
addr = FFI::Pointer.new :pointer, 0x057C75F8

res = Memory::read(handle, addr, out, 4, read)

# get_pointer(0) grabs the pointer to the value
# address holds the value we actually want (at least in this case)
read = read.get_pointer(0).address
out = out.get_pointer(0).address

puts "GetLastError: #{Memory::error()}"
puts "ReadProcessMemory: #{res}"
puts "Bytes Read: #{read}"
puts "Value Read: #{out}"
Memory::close(handle)

我特定情况下的上述代码正确输出以下内容：

GetLastError: 0
GetLastError: 0
ReadProcessMemory: true
Bytes Read: 4
Value Read: 10

我希望这将有助于将来。

Ruby中的Read / WriteProcessMemory

1 个答案: