636 lines
14 KiB
C++
636 lines
14 KiB
C++
// vim: set ts=4 sw=4 tw=99 noet:
|
|
//
|
|
// AMX Mod X, based on AMX Mod by Aleksander Naszko ("OLO").
|
|
// Copyright (C) The AMX Mod X Development Team.
|
|
//
|
|
// This software is licensed under the GNU General Public License, version 3 or higher.
|
|
// Additional exceptions apply. For full license details, see LICENSE.txt or visit:
|
|
// https://alliedmods.net/amxmodx-license
|
|
|
|
//
|
|
// Ham Sandwich Module
|
|
//
|
|
|
|
#ifndef TRAMPOLINES_H
|
|
#define TRAMPOLINES_H
|
|
|
|
#ifndef NDEBUG
|
|
#define TPRINT(msg) printf msg
|
|
#else
|
|
#define TPRINT(msg) /* nothing */
|
|
#endif
|
|
|
|
#if defined _WIN32
|
|
#ifndef WIN32_LEAN_AND_MEAN
|
|
#define WIN32_LEAN_AND_MEAN
|
|
#endif // WIN32_LEAN_AND_MEAN
|
|
#if _MSC_VER >= 1400
|
|
#ifdef offsetof
|
|
#undef offsetof
|
|
#endif // offsetof
|
|
#endif // _MSC_VER >= 1400
|
|
#include <windows.h>
|
|
#elif defined(__linux__) || defined(__APPLE__)
|
|
#include <sys/mman.h>
|
|
#if defined (__linux__)
|
|
#include <malloc.h>
|
|
#endif
|
|
#endif
|
|
#include <stddef.h> // size_t
|
|
#include <string.h> // memcpy
|
|
#include <stdlib.h> // memalign
|
|
#include <stdio.h>
|
|
|
|
#include <amtl/am-utility.h>
|
|
|
|
namespace Trampolines
|
|
{
|
|
|
|
/**
|
|
* List of x86 bytecodes for creating
|
|
* basic trampolines at runtime.
|
|
* -
|
|
* These are defined here so that, should
|
|
* the need ever arise, this can be ported
|
|
* to other architectures fairly painlessly
|
|
*/
|
|
namespace Bytecode
|
|
{
|
|
/**
|
|
* Prologue for a function
|
|
*/
|
|
const unsigned char codePrologue[] = {
|
|
0x55, // push ebp
|
|
0x89, 0xE5, // mov ebp, esp
|
|
};
|
|
|
|
/**
|
|
* Align stack on 16 byte boundary
|
|
*/
|
|
const unsigned char codeAlignStack16[] = {
|
|
0x83, 0xE4, 0xF0, // and esp, 0xFFFFFFF0
|
|
};
|
|
|
|
/**
|
|
* Allocate stack space (8-bit) by adding to ESP
|
|
*/
|
|
const unsigned char codeAllocStack[] = {
|
|
0x83, 0xEC, 0xFF, // sub esp, 0xFF
|
|
};
|
|
|
|
/**
|
|
* Offset of codeAllocStack to modify at runtime
|
|
* to contain amount of stack space to allocate.
|
|
*/
|
|
const unsigned int codeAllocStackReplace = 2;
|
|
|
|
/**
|
|
* Takes a paramter from the trampoline's stack
|
|
* and pushes it onto the target's stack.
|
|
*/
|
|
const unsigned char codePushParam[] = {
|
|
0xFF, 0x75, 0xFF // pushl [ebp+0xFF]
|
|
};
|
|
|
|
/**
|
|
* Offset of codePushParam to modify at runtime
|
|
* that contains the stack offset
|
|
*/
|
|
const unsigned int codePushParamReplace = 2;
|
|
|
|
|
|
/**
|
|
* Takes the "this" pointer from the trampoline and
|
|
* pushes it onto the target's stack.
|
|
*/
|
|
const unsigned char codePushThis[] = {
|
|
#if defined(_WIN32)
|
|
0x51 // push ecx
|
|
#elif defined(__linux__) || defined(__APPLE__)
|
|
0xFF, 0x75, 0x04 // pushl [ebp+0x08h]
|
|
#endif
|
|
};
|
|
|
|
#if defined(__linux__) || defined(__APPLE__)
|
|
const int codePushThisReplace = 2;
|
|
#endif
|
|
|
|
/**
|
|
* Pushes a raw number onto the target's stack
|
|
*/
|
|
const unsigned char codePushID[] = {
|
|
0x68, 0xDE, 0xFA, 0xAD, 0xDE // push DEADFADEh
|
|
};
|
|
|
|
/**
|
|
* Offset of codePushID to modify at runtime
|
|
* to contain the number to push
|
|
*/
|
|
const unsigned int codePushIDReplace = 1;
|
|
|
|
/**
|
|
* Call our procedure
|
|
*/
|
|
const unsigned char codeCall[] = {
|
|
0xB8, 0xDE, 0xFA, 0xAD, 0xDE,// mov eax, DEADFADEh
|
|
0xFF, 0xD0 // call eax
|
|
};
|
|
|
|
/**
|
|
* Offset of codeCall to modify at runtime
|
|
* to contain the pointer to the function
|
|
*/
|
|
const unsigned int codeCallReplace = 1;
|
|
|
|
/**
|
|
* Adds to ESP, freeing up stack space
|
|
*/
|
|
const unsigned char codeFreeStack[] = {
|
|
0x81, 0xC4, 0xFF, 0xFF, 0xFF, 0xFF// add esp REPLACEME
|
|
};
|
|
|
|
/**
|
|
* Offset of codeFreeStack to modify at runtime
|
|
* to contain how much data to free
|
|
*/
|
|
const unsigned int codeFreeStackReplace = 2;
|
|
|
|
/**
|
|
* Epilogue of a simple function
|
|
*/
|
|
const unsigned char codeEpilogue[] = {
|
|
0x89, 0xEC, // mov esp, ebp
|
|
0x5D, // pop ebp
|
|
0xC3 // ret
|
|
};
|
|
const unsigned char codeEpilogueN[] = {
|
|
0x89, 0xEC, // mov esp, ebp
|
|
0x5D, // pop ebp
|
|
0xC2, 0xCD, 0xAB // retn 0xABCD
|
|
};
|
|
const int codeEpilogueNReplace = 4;
|
|
|
|
const unsigned char codeBreakpoint[] = {
|
|
0xCC // int 3
|
|
};
|
|
|
|
}
|
|
|
|
/**
|
|
* Our actual maker of the trampolines!!@$
|
|
* I've no idea why I made this a class and not a namespace
|
|
* Oh well!
|
|
*/
|
|
|
|
class TrampolineMaker
|
|
{
|
|
private:
|
|
unsigned char *m_buffer; // the actual buffer containing the code
|
|
int m_size; // size of the buffer
|
|
int m_mystack; // stack for the trampoline itself
|
|
int m_calledstack; // stack for the target function
|
|
int m_paramstart;
|
|
int m_thiscall;
|
|
int m_maxsize;
|
|
|
|
/**
|
|
* Adds data to the buffer
|
|
* data must be pre-formatted before hand!
|
|
*/
|
|
void Append(const unsigned char *src, size_t size)
|
|
{
|
|
int orig=m_size;
|
|
m_size+=size;
|
|
|
|
if (m_buffer==NULL)
|
|
{
|
|
m_maxsize=512;
|
|
m_buffer=(unsigned char *)malloc(m_maxsize);
|
|
}
|
|
else if (m_size > m_maxsize)
|
|
{
|
|
m_maxsize = m_size + 512;
|
|
m_buffer=(unsigned char *)realloc(m_buffer,m_maxsize);
|
|
}
|
|
|
|
unsigned char *dat=m_buffer+orig; // point dat to the end of the prewritten
|
|
|
|
while (orig<m_size)
|
|
{
|
|
*dat++=*src++;
|
|
|
|
orig++;
|
|
};
|
|
|
|
};
|
|
public:
|
|
TrampolineMaker()
|
|
{
|
|
m_buffer=NULL;
|
|
m_size=0;
|
|
m_mystack=0;
|
|
m_calledstack=0;
|
|
m_paramstart=0;
|
|
m_thiscall=0;
|
|
m_maxsize=0;
|
|
};
|
|
|
|
/**
|
|
* Inserts a breakpoint (int 3) into the trampoline.
|
|
*/
|
|
void Breakpoint()
|
|
{
|
|
Append(&::Trampolines::Bytecode::codeBreakpoint[0],sizeof(::Trampolines::Bytecode::codeBreakpoint));
|
|
};
|
|
|
|
/**
|
|
* Adds the prologue, pushes registers, prepares the stack
|
|
*/
|
|
void Prologue()
|
|
{
|
|
Append(&::Trampolines::Bytecode::codePrologue[0],sizeof(::Trampolines::Bytecode::codePrologue));
|
|
m_paramstart=0;
|
|
m_thiscall=0;
|
|
};
|
|
|
|
/**
|
|
* Flags this trampoline as a thiscall trampoline, and prepares the prologue.
|
|
*/
|
|
void ThisPrologue()
|
|
{
|
|
this->Prologue();
|
|
m_thiscall=1;
|
|
};
|
|
|
|
/**
|
|
* Epilogue for a function pops registers but does not free any more of the stack!
|
|
*/
|
|
void Epilogue()
|
|
{
|
|
Append(&::Trampolines::Bytecode::codeEpilogue[0],sizeof(::Trampolines::Bytecode::codeEpilogue));
|
|
};
|
|
|
|
/**
|
|
* Epilogue that also frees it's estimated stack usage. Useful for stdcall/thiscall/fastcall.
|
|
*/
|
|
void EpilogueAndFree()
|
|
{
|
|
this->Epilogue(m_mystack);
|
|
};
|
|
|
|
/**
|
|
* Epilogue. Pops registers, and frees given amount of data from the stack.
|
|
*
|
|
* @param howmuch How many bytes to free from the stack.
|
|
*/
|
|
void Epilogue(int howmuch)
|
|
{
|
|
unsigned char code[sizeof(::Trampolines::Bytecode::codeEpilogueN)];
|
|
|
|
memcpy(&code[0],&::Trampolines::Bytecode::codeEpilogueN[0],sizeof(::Trampolines::Bytecode::codeEpilogueN));
|
|
|
|
|
|
unsigned char *c=&code[0];
|
|
|
|
union
|
|
{
|
|
int i;
|
|
unsigned char b[4];
|
|
} bi;
|
|
|
|
bi.i=howmuch;
|
|
|
|
c+=::Trampolines::Bytecode::codeEpilogueNReplace;
|
|
*c++=bi.b[0];
|
|
*c++=bi.b[1];
|
|
|
|
Append(&code[0],sizeof(::Trampolines::Bytecode::codeEpilogueN));
|
|
};
|
|
|
|
/**
|
|
* Aligns stack on 16 byte boundary for functions that use aligned SSE instructions.
|
|
* This also allocates extra stack space to allow the specified number of slots to be used
|
|
* for function paramaters that will be pushed onto the stack.
|
|
*/
|
|
void AlignStack16(int slots)
|
|
{
|
|
const size_t stackNeeded = slots * sizeof(void *);
|
|
const size_t stackReserve = ke::Align(stackNeeded, 16);
|
|
const size_t stackExtra = stackReserve - stackNeeded;
|
|
|
|
// Stack space should fit in a byte
|
|
assert(stackExtra <= 0xFF);
|
|
|
|
const size_t codeAlignStackSize = sizeof(::Trampolines::Bytecode::codeAlignStack16);
|
|
const size_t codeAllocStackSize = sizeof(::Trampolines::Bytecode::codeAllocStack);
|
|
unsigned char code[codeAlignStackSize + codeAllocStackSize];
|
|
|
|
memcpy(&code[0], &::Trampolines::Bytecode::codeAlignStack16[0], codeAlignStackSize);
|
|
|
|
if (stackExtra > 0)
|
|
{
|
|
unsigned char *c = &code[codeAlignStackSize];
|
|
memcpy(c, &::Trampolines::Bytecode::codeAllocStack[0], codeAllocStackSize);
|
|
|
|
c += ::Trampolines::Bytecode::codeAllocStackReplace;
|
|
*c = (unsigned char)stackExtra;
|
|
|
|
Append(&code[0], codeAlignStackSize + codeAllocStackSize);
|
|
}
|
|
else
|
|
{
|
|
Append(&code[0], codeAlignStackSize);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Pushes the "this" pointer onto the callee stack. Pushes ECX for MSVC, and param0 on GCC.
|
|
*/
|
|
void PushThis()
|
|
{
|
|
|
|
if (!m_thiscall)
|
|
{
|
|
return;
|
|
}
|
|
|
|
unsigned char code[sizeof(::Trampolines::Bytecode::codePushThis)];
|
|
|
|
memcpy(&code[0],&::Trampolines::Bytecode::codePushThis[0],sizeof(::Trampolines::Bytecode::codePushThis));
|
|
|
|
|
|
#if defined(__linux__) || defined(__APPLE__)
|
|
unsigned char *c=&code[0];
|
|
|
|
union
|
|
{
|
|
int i;
|
|
unsigned char b[4];
|
|
} bi;
|
|
|
|
bi.i=m_paramstart+8;
|
|
|
|
c+=::Trampolines::Bytecode::codePushThisReplace;
|
|
*c++=bi.b[0];
|
|
#endif
|
|
|
|
Append(&code[0],sizeof(::Trampolines::Bytecode::codePushThis));
|
|
|
|
#if defined(__linux__) || defined(__APPLE__)
|
|
m_mystack+=4;
|
|
#endif
|
|
m_calledstack+=4;
|
|
};
|
|
|
|
/**
|
|
* Frees what is estimated as the stack usage of the trampoline.
|
|
*/
|
|
void FreeMyStack(void)
|
|
{
|
|
|
|
this->FreeStack(m_mystack);
|
|
};
|
|
|
|
/**
|
|
* Frees the estimated stack usage of the callee.
|
|
*/
|
|
void FreeTargetStack(void)
|
|
{
|
|
this->FreeStack(m_calledstack);
|
|
};
|
|
|
|
|
|
/**
|
|
* Frees the estimated stack usage of the callee and the trampoline.
|
|
*/
|
|
void FreeBothStacks(void)
|
|
{
|
|
this->FreeStack(m_calledstack + m_mystack);
|
|
};
|
|
|
|
/**
|
|
* Frees a given amount of bytes from the stack.
|
|
*
|
|
* @param howmuch How many bytes to free.
|
|
*/
|
|
void FreeStack(int howmuch)
|
|
{
|
|
unsigned char code[sizeof(::Trampolines::Bytecode::codeFreeStack)];
|
|
|
|
memcpy(&code[0],&::Trampolines::Bytecode::codeFreeStack[0],sizeof(::Trampolines::Bytecode::codeFreeStack));
|
|
|
|
unsigned char *c=&code[0];
|
|
|
|
union
|
|
{
|
|
int i;
|
|
unsigned char b[4];
|
|
} bi;
|
|
|
|
bi.i=howmuch;
|
|
|
|
c+=::Trampolines::Bytecode::codeFreeStackReplace;
|
|
*c++=bi.b[0];
|
|
*c++=bi.b[1];
|
|
*c++=bi.b[2];
|
|
*c++=bi.b[3];
|
|
|
|
Append(&code[0],sizeof(::Trampolines::Bytecode::codeFreeStack));
|
|
|
|
};
|
|
|
|
/**
|
|
* Pushes a raw number onto the callee stack.
|
|
*
|
|
* @param Number The number to push onto the callee stack.
|
|
*/
|
|
void PushNum(int Number)
|
|
{
|
|
unsigned char code[sizeof(::Trampolines::Bytecode::codePushID)];
|
|
|
|
memcpy(&code[0],&::Trampolines::Bytecode::codePushID[0],sizeof(::Trampolines::Bytecode::codePushID));
|
|
|
|
unsigned char *c=&code[0];
|
|
|
|
union
|
|
{
|
|
int i;
|
|
unsigned char b[4];
|
|
} bi;
|
|
|
|
bi.i=Number;
|
|
|
|
c+=::Trampolines::Bytecode::codePushIDReplace;
|
|
*c++=bi.b[0];
|
|
*c++=bi.b[1];
|
|
*c++=bi.b[2];
|
|
*c++=bi.b[3];
|
|
|
|
Append(&code[0],sizeof(::Trampolines::Bytecode::codePushID));
|
|
|
|
m_calledstack+=4; // increase auto detected stack size
|
|
|
|
};
|
|
|
|
|
|
/**
|
|
* Takes a parameter passed on the trampoline's stack and inserts it into the callee's stack.
|
|
*
|
|
* @param which The parameter number to push. 1-based. "thiscall" trampolines automatically compensate for the off-number on GCC.
|
|
*/
|
|
void PushParam(int which)
|
|
{
|
|
#if defined(__linux__) || defined(__APPLE__)
|
|
if (m_thiscall)
|
|
{
|
|
which++;
|
|
}
|
|
#endif
|
|
which=which*4;
|
|
which+=m_paramstart+4;
|
|
|
|
unsigned char value=which;
|
|
|
|
unsigned char code[sizeof(::Trampolines::Bytecode::codePushParam)];
|
|
|
|
memcpy(&code[0],&::Trampolines::Bytecode::codePushParam[0],sizeof(::Trampolines::Bytecode::codePushParam));
|
|
|
|
unsigned char *c=&code[0];
|
|
|
|
|
|
c+=::Trampolines::Bytecode::codePushParamReplace;
|
|
|
|
*c=value;
|
|
|
|
Append(&code[0],sizeof(::Trampolines::Bytecode::codePushParam));
|
|
|
|
m_calledstack+=4; // increase auto detected stack size
|
|
m_mystack+=4;
|
|
|
|
};
|
|
|
|
/**
|
|
* Insert a function to call into the trampoline.
|
|
*
|
|
* @param ptr The function to call, cast to void*.
|
|
*/
|
|
void Call(void *ptr)
|
|
{
|
|
unsigned char code[sizeof(::Trampolines::Bytecode::codeCall)];
|
|
|
|
memcpy(&code[0],&::Trampolines::Bytecode::codeCall[0],sizeof(::Trampolines::Bytecode::codeCall));
|
|
|
|
unsigned char *c=&code[0];
|
|
|
|
union
|
|
{
|
|
void *p;
|
|
unsigned char b[4];
|
|
} bp;
|
|
|
|
bp.p=ptr;
|
|
|
|
c+=::Trampolines::Bytecode::codeCallReplace;
|
|
|
|
*c++=bp.b[0];
|
|
*c++=bp.b[1];
|
|
*c++=bp.b[2];
|
|
*c++=bp.b[3];
|
|
Append(&code[0],sizeof(::Trampolines::Bytecode::codeCall));
|
|
|
|
|
|
};
|
|
|
|
/**
|
|
* Finalizes the trampoline. Do not try to modify it after this.
|
|
*
|
|
* @param size A pointer to retrieve the size of the trampoline. Ignored if set to NULL.
|
|
* @return The trampoline pointer, cast to void*.
|
|
*/
|
|
void *Finish(int *size)
|
|
{
|
|
//void *ret=(void *)m_buffer;
|
|
|
|
if (size)
|
|
{
|
|
*size=m_size;
|
|
}
|
|
|
|
// Reallocate with proper flags
|
|
#if defined(_WIN32)
|
|
void *ret=VirtualAlloc(NULL, m_size, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
|
|
#elif defined(__GNUC__)
|
|
# if defined(__APPLE__)
|
|
void *ret = valloc(m_size);
|
|
# else
|
|
void *ret=memalign(sysconf(_SC_PAGESIZE), m_size);
|
|
# endif
|
|
mprotect(ret,m_size,PROT_READ|PROT_WRITE|PROT_EXEC);
|
|
#endif
|
|
memcpy(ret, m_buffer, m_size);
|
|
|
|
|
|
m_size=0;
|
|
|
|
free(m_buffer);
|
|
|
|
m_buffer=NULL; // so we don't accidentally rewrite!
|
|
m_mystack=0;
|
|
m_calledstack=0;
|
|
m_maxsize=512;
|
|
|
|
return ret;
|
|
};
|
|
};
|
|
};
|
|
|
|
|
|
/**
|
|
* Utility to make a generic trampoline.
|
|
*/
|
|
inline void *CreateGenericTrampoline(bool thiscall, bool voidcall, bool retbuf, int paramcount, void *extraptr, void *callee)
|
|
{
|
|
Trampolines::TrampolineMaker tramp;
|
|
|
|
if (thiscall)
|
|
{
|
|
tramp.ThisPrologue();
|
|
tramp.AlignStack16(paramcount + 2); // Param count + this ptr + extra ptr
|
|
}
|
|
else
|
|
{
|
|
tramp.Prologue();
|
|
tramp.AlignStack16(paramcount + 1); // Param count + extra ptr
|
|
}
|
|
|
|
while (paramcount)
|
|
{
|
|
tramp.PushParam(paramcount--);
|
|
}
|
|
if (thiscall)
|
|
{
|
|
tramp.PushThis();
|
|
}
|
|
tramp.PushNum(reinterpret_cast<int>(extraptr));
|
|
tramp.Call(callee);
|
|
tramp.FreeTargetStack();
|
|
|
|
#if defined(_WIN32)
|
|
tramp.EpilogueAndFree();
|
|
#elif defined(__linux__) || defined(__APPLE__)
|
|
if (retbuf)
|
|
{
|
|
tramp.Epilogue(4);
|
|
}
|
|
else
|
|
{
|
|
tramp.Epilogue();
|
|
}
|
|
#endif
|
|
|
|
return tramp.Finish(NULL);
|
|
};
|
|
|
|
|
|
#endif // TRAMPOLINEMANAGER_H
|