gecko/toolkit/xre/nsWindowsDllInterceptor.h

383 lines
11 KiB
C++

/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is the Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2009
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Vladimir Vukicevic <vladimir@pobox.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef NS_WINDOWS_DLL_INTERCEPTOR_H_
#define NS_WINDOWS_DLL_INTERCEPTOR_H_
#include <windows.h>
#include <winternl.h>
/*
* Simple trampoline interception
*
* 1. Save first N bytes of OrigFunction to trampoline, where N is a
* number of bytes >= 5 that are instruction aligned.
*
* 2. Replace first 5 bytes of OrigFunction with a jump to the Hook
* function.
*
* 3. After N bytes of the trampoline, add a jump to OrigFunction+N to
* continue original program flow.
*
* 4. Hook function needs to call the trampoline during its execution,
* to invoke the original function (so address of trampoline is
* returned).
*
*/
class WindowsDllInterceptor
{
typedef unsigned char *byteptr_t;
public:
WindowsDllInterceptor()
: mModule(0)
{
}
WindowsDllInterceptor(const char *modulename, int nhooks = 0) {
Init(modulename, nhooks);
}
void Init(const char *modulename, int nhooks = 0) {
if (mModule)
return;
mModule = LoadLibraryExA(modulename, NULL, 0);
if (!mModule) {
//printf("LoadLibraryEx for '%s' failed\n", modulename);
return;
}
int hooksPerPage = 4096 / kHookSize;
if (nhooks == 0)
nhooks = hooksPerPage;
mMaxHooks = nhooks + (hooksPerPage % nhooks);
mCurHooks = 0;
mHookPage = (byteptr_t) VirtualAllocEx(GetCurrentProcess(), NULL, mMaxHooks * kHookSize,
MEM_COMMIT | MEM_RESERVE,
PAGE_EXECUTE_READWRITE);
if (!mHookPage) {
mModule = 0;
return;
}
}
void LockHooks() {
if (!mModule)
return;
DWORD op;
VirtualProtectEx(GetCurrentProcess(), mHookPage, mMaxHooks * kHookSize, PAGE_EXECUTE_READ, &op);
mModule = 0;
}
bool AddHook(const char *pname,
intptr_t hookDest,
void **origFunc)
{
if (!mModule)
return false;
void *pAddr = (void *) GetProcAddress(mModule, pname);
if (!pAddr) {
//printf ("GetProcAddress failed\n");
return false;
}
void *tramp = CreateTrampoline(pAddr, hookDest);
if (!tramp) {
//printf ("CreateTrampoline failed\n");
return false;
}
*origFunc = tramp;
return true;
}
protected:
const static int kPageSize = 4096;
const static int kHookSize = 128;
HMODULE mModule;
byteptr_t mHookPage;
int mMaxHooks;
int mCurHooks;
byteptr_t CreateTrampoline(void *origFunction,
intptr_t dest)
{
byteptr_t tramp = FindTrampolineSpace();
if (!tramp)
return 0;
byteptr_t origBytes = (byteptr_t) origFunction;
int nBytes = 0;
#if defined(_M_IX86)
while (nBytes < 5) {
// Understand some simple instructions that might be found in a
// prologue; we might need to extend this as necessary.
//
// Note! If we ever need to understand jump instructions, we'll
// need to rewrite the displacement argument.
if (origBytes[nBytes] >= 0x88 && origBytes[nBytes] <= 0x8B) {
// various MOVs; but only handle the case where it truly is a 2-byte instruction
unsigned char b = origBytes[nBytes+1];
if (((b & 0xc0) == 0xc0) ||
(((b & 0xc0) == 0x00) &&
((b & 0x38) != 0x20) && ((b & 0x38) != 0x28)))
{
nBytes += 2;
} else {
// complex MOV, bail
return 0;
}
} else if (origBytes[nBytes] == 0x68) {
// PUSH with 4-byte operand
nBytes += 5;
} else if ((origBytes[nBytes] & 0xf0) == 0x50) {
// 1-byte PUSH/POP
nBytes++;
} else if (origBytes[nBytes] == 0x6A) {
// PUSH imm8
nBytes += 2;
} else {
//printf ("Unknown x86 instruction byte 0x%02x, aborting trampoline\n", origBytes[nBytes]);
return 0;
}
}
#elif defined(_M_X64)
int pJmp32 = -1;
while (nBytes < 13) {
// if found JMP 32bit offset, next bytes must be NOP
if (pJmp32 >= 0) {
if (origBytes[nBytes++] != 0x90)
return 0;
continue;
}
if (origBytes[nBytes] == 0x41) {
// REX.B
nBytes++;
if ((origBytes[nBytes] & 0xf0) == 0x50) {
// push/pop with Rx register
nBytes++;
} else if (origBytes[nBytes] >= 0xb8 && origBytes[nBytes] <= 0xbf) {
// mov r32, imm32
nBytes += 5;
} else {
return 0;
}
} else if (origBytes[nBytes] == 0x45) {
// REX.R & REX.B
nBytes++;
if (origBytes[nBytes] == 0x33) {
// xor r32, r32
nBytes += 2;
} else {
return 0;
}
} else if (origBytes[nBytes] == 0x48) {
// REX.W
nBytes++;
if (origBytes[nBytes] == 0x81 && (origBytes[nBytes+1] & 0xf8) == 0xe8) {
// sub r, dword
nBytes += 6;
} else if (origBytes[nBytes] == 0x83 &&
(origBytes[nBytes+1] & 0xf8) == 0xe8) {
// sub r, byte
nBytes += 3;
} else if (origBytes[nBytes] == 0x83 &&
(origBytes[nBytes+1] & 0xf8) == 0x60) {
// and [r+d], imm8
nBytes += 5;
} else if (origBytes[nBytes] == 0x89) {
// MOV r/m64, r64
if ((origBytes[nBytes+1] & 0xc0) == 0x40) {
if ((origBytes[nBytes+1] & 0x7) == 0x04) {
// mov [SIB+disp8], r64
nBytes += 4;
} else {
// mov [r64+disp8], r64
nBytes += 3;
}
} else {
// complex mov
return 0;
}
} else if (origBytes[nBytes] == 0x8b) {
// mov r64, r/m64
if ((origBytes[nBytes+1] & 0xc0) == 0x40) {
if ((origBytes[nBytes+1] & 0x7) == 0x04) {
// mov r64, [SIB+disp8]
nBytes += 4;
} else {
// mov r64, [r64+disp8]
nBytes += 3;
}
} else if ((origBytes[nBytes+1] & 0xc0) == 0xc0) {
// MOV r64, r64
nBytes += 2;
} else {
// complex MOV
return 0;
}
} else {
// not support yet!
return 0;
}
} else if ((origBytes[nBytes] & 0xf0) == 0x50) {
// 1-byte push/pop
nBytes++;
} else if (origBytes[nBytes] == 0x90) {
// nop
nBytes++;
} else if (origBytes[nBytes] == 0xe9) {
pJmp32 = nBytes;
// jmp 32bit offset
nBytes += 5;
} else if (origBytes[nBytes] == 0xff) {
nBytes++;
if ((origBytes[nBytes] & 0xf8) == 0xf0) {
// push r64
nBytes++;
} else {
return 0;
}
} else {
return 0;
}
}
#else
#error "Unknown processor type"
#endif
if (nBytes > 100) {
//printf ("Too big!");
return 0;
}
memcpy(tramp, origFunction, nBytes);
// OrigFunction+N, the target of the trampoline
byteptr_t trampDest = origBytes + nBytes;
#if defined(_M_IX86)
tramp[nBytes] = 0xE9; // jmp
*((intptr_t*)(tramp+nBytes+1)) = (intptr_t)trampDest - (intptr_t)(tramp+nBytes+5); // target displacement
#elif defined(_M_X64)
// If JMP32 opcode found, we don't insert to trampoline jump
if (pJmp32 >= 0) {
// convert JMP 32bit offset to JMP 64bit direct
byteptr_t directJmpAddr = origBytes + pJmp32 + 5 + (*((LONG*)(origBytes+pJmp32+1)));
// mov r11, address
tramp[pJmp32] = 0x49;
tramp[pJmp32+1] = 0xbb;
*((intptr_t*)(tramp+pJmp32+2)) = (intptr_t)directJmpAddr;
// jmp r11
tramp[pJmp32+10] = 0x41;
tramp[pJmp32+11] = 0xff;
tramp[pJmp32+12] = 0xe3;
} else {
// mov r11, address
tramp[nBytes] = 0x49;
tramp[nBytes+1] = 0xbb;
*((intptr_t*)(tramp+nBytes+2)) = (intptr_t)trampDest;
// jmp r11
tramp[nBytes+10] = 0x41;
tramp[nBytes+11] = 0xff;
tramp[nBytes+12] = 0xe3;
}
#endif
// ensure we can modify the original code
DWORD op;
if (!VirtualProtectEx(GetCurrentProcess(), origFunction, nBytes, PAGE_EXECUTE_READWRITE, &op)) {
//printf ("VirtualProtectEx failed! %d\n", GetLastError());
return 0;
}
#if defined(_M_IX86)
// now modify the original bytes
origBytes[0] = 0xE9; // jmp
*((intptr_t*)(origBytes+1)) = dest - (intptr_t)(origBytes+5); // target displacement
#elif defined(_M_X64)
// mov r11, address
origBytes[0] = 0x49;
origBytes[1] = 0xbb;
*((intptr_t*)(origBytes+2)) = dest;
// jmp r11
origBytes[10] = 0x41;
origBytes[11] = 0xff;
origBytes[12] = 0xe3;
#endif
// restore protection; if this fails we can't really do anything about it
VirtualProtectEx(GetCurrentProcess(), origFunction, nBytes, op, &op);
return tramp;
}
byteptr_t FindTrampolineSpace() {
if (mCurHooks >= mMaxHooks)
return 0;
byteptr_t p = mHookPage + mCurHooks*kHookSize;
mCurHooks++;
return p;
}
};
#endif /* NS_WINDOWS_DLL_INTERCEPTOR_H_ */