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/* $Id: PATMGuest.cpp $ */
/** @file
* PATMGuest - Guest OS Patching Manager (non-generic)
*/
/*
* Copyright (C) 2006-2019 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#define LOG_GROUP LOG_GROUP_PATM
#include <VBox/vmm/patm.h>
#include <VBox/vmm/pgm.h>
#include <VBox/vmm/iom.h>
#include <VBox/param.h>
#include <iprt/avl.h>
#include "PATMInternal.h"
#include <VBox/vmm/vm.h>
#include <VBox/vmm/csam.h>
#include <VBox/dbg.h>
#include <VBox/err.h>
#include <VBox/log.h>
#include <iprt/assert.h>
#include <iprt/string.h>
#include <VBox/dis.h>
#include <VBox/disopcode.h>
/*
* ntdll!KiFastSystemCall:
* 7c90eb8b 8bd4 mov edx,esp
* 7c90eb8d 0f34 sysenter
* 7c90eb8f 90 nop
* 7c90eb90 90 nop
* 7c90eb91 90 nop
* 7c90eb92 90 nop
* 7c90eb93 90 nop
* ntdll!KiFastSystemCallRet:
* 7c90eb94 c3 ret
*
* ntdll!KiIntSystemCall:
* 7c90eba5 8d542408 lea edx,[esp+0x8]
* 7c90eba9 cd2e int 2e
* 7c90ebab c3 ret
*
*/
static uint8_t uFnKiFastSystemCall[7] = {0x8b, 0xd4, 0x0f, 0x34, 0x90, 0x90, 0x90};
static uint8_t uFnKiIntSystemCall[7] = {0x8d, 0x54, 0x24, 0x08, 0xcd, 0x2e, 0xc3};
/*
* OpenBSD 3.7 & 3.8:
*
* D0101B6D: push CS [0E]
* D0101B6E: push ESI [56]
* D0101B6F: cli [FA]
*/
static uint8_t uFnOpenBSDHandlerPrefix1[3] = { 0x0E, 0x56, 0xFA };
/*
* OpenBSD 3.9 & 4.0
*
* D0101BD1: push CS [0E]
* D0101BD2: push ESI [56]
* D0101BD3: push 0x00 [6A 00]
* D0101BD4: push 0x03 [6A 03]
*/
static uint8_t uFnOpenBSDHandlerPrefix2[6] = { 0x0E, 0x56, 0x6A, 0x00, 0x6A, 0x03 };
/**
* Check Windows XP sysenter heuristics and install patch
*
* @returns VBox status code.
* @param pVM The cross context VM structure.
* @param pInstrGC GC Instruction pointer for sysenter
* @param pPatchRec Patch structure
*
*/
int PATMPatchSysenterXP(PVM pVM, RTGCPTR32 pInstrGC, PPATMPATCHREC pPatchRec)
{
PPATCHINFO pPatch = &pPatchRec->patch;
uint8_t uTemp[16];
RTGCPTR32 lpfnKiFastSystemCall, lpfnKiIntSystemCall = 0; /* (initializing it to shut up warning.) */
int rc, i;
PVMCPU pVCpu = VMMGetCpu0(pVM);
Assert(sizeof(uTemp) > sizeof(uFnKiIntSystemCall));
Assert(sizeof(uTemp) > sizeof(uFnKiFastSystemCall));
/* Guest OS specific patch; check heuristics first */
/* check the epilog of KiFastSystemCall */
lpfnKiFastSystemCall = pInstrGC - 2;
rc = PGMPhysSimpleReadGCPtr(pVCpu, uTemp, lpfnKiFastSystemCall, sizeof(uFnKiFastSystemCall));
if ( RT_FAILURE(rc)
|| memcmp(uFnKiFastSystemCall, uTemp, sizeof(uFnKiFastSystemCall)))
{
return VERR_PATCHING_REFUSED;
}
/* Now search for KiIntSystemCall */
for (i=0;i<64;i++)
{
rc = PGMPhysSimpleReadGCPtr(pVCpu, uTemp, pInstrGC + i, sizeof(uFnKiIntSystemCall));
if(RT_FAILURE(rc))
{
break;
}
if(!memcmp(uFnKiIntSystemCall, uTemp, sizeof(uFnKiIntSystemCall)))
{
lpfnKiIntSystemCall = pInstrGC + i;
/* Found it! */
break;
}
}
if (i == 64)
{
Log(("KiIntSystemCall not found!!\n"));
return VERR_PATCHING_REFUSED;
}
if (PAGE_ADDRESS(lpfnKiFastSystemCall) != PAGE_ADDRESS(lpfnKiIntSystemCall))
{
Log(("KiFastSystemCall and KiIntSystemCall not in the same page!!\n"));
return VERR_PATCHING_REFUSED;
}
// make a copy of the guest code bytes that will be overwritten
rc = PGMPhysSimpleReadGCPtr(pVCpu, pPatch->aPrivInstr, pPatch->pPrivInstrGC, SIZEOF_NEARJUMP32);
AssertRC(rc);
/* Now we simply jump from the fast version to the 'old and slow' system call */
uTemp[0] = 0xE9;
*(RTGCPTR32 *)&uTemp[1] = lpfnKiIntSystemCall - (pInstrGC + SIZEOF_NEARJUMP32);
rc = PGMPhysSimpleDirtyWriteGCPtr(pVCpu, pInstrGC, uTemp, SIZEOF_NEARJUMP32);
if (RT_FAILURE(rc))
{
Log(("PGMPhysSimpleDirtyWriteGCPtr failed with rc=%Rrc!!\n", rc));
return VERR_PATCHING_REFUSED;
}
#ifdef LOG_ENABLED
Log(("Sysenter Patch code ----------------------------------------------------------\n"));
PATMP2GLOOKUPREC cacheRec;
RT_ZERO(cacheRec);
cacheRec.pPatch = pPatch;
patmr3DisasmCodeStream(pVM, pInstrGC, pInstrGC, patmR3DisasmCallback, &cacheRec);
/* Free leftover lock if any. */
if (cacheRec.Lock.pvMap)
PGMPhysReleasePageMappingLock(pVM, &cacheRec.Lock);
Log(("Sysenter Patch code ends -----------------------------------------------------\n"));
#endif
pPatch->uState = PATCH_ENABLED;
return VINF_SUCCESS;
}
/**
* Patch OpenBSD interrupt handler prefix
*
* @returns VBox status code.
* @param pVM The cross context VM structure.
* @param pCpu Disassembly state of instruction.
* @param pInstrGC GC Instruction pointer for instruction
* @param pInstrHC GC Instruction pointer for instruction
* @param pPatchRec Patch structure
*
*/
int PATMPatchOpenBSDHandlerPrefix(PVM pVM, PDISCPUSTATE pCpu, RTGCPTR32 pInstrGC, uint8_t *pInstrHC, PPATMPATCHREC pPatchRec)
{
uint8_t uTemp[16];
int rc;
Assert(sizeof(uTemp) > RT_MAX(sizeof(uFnOpenBSDHandlerPrefix1), sizeof(uFnOpenBSDHandlerPrefix2)));
/* Guest OS specific patch; check heuristics first */
rc = PGMPhysSimpleReadGCPtr(VMMGetCpu0(pVM), uTemp, pInstrGC, RT_MAX(sizeof(uFnOpenBSDHandlerPrefix1), sizeof(uFnOpenBSDHandlerPrefix2)));
if ( RT_FAILURE(rc)
|| ( memcmp(uFnOpenBSDHandlerPrefix1, uTemp, sizeof(uFnOpenBSDHandlerPrefix1))
&& memcmp(uFnOpenBSDHandlerPrefix2, uTemp, sizeof(uFnOpenBSDHandlerPrefix2))))
{
return VERR_PATCHING_REFUSED;
}
/* Found it; patch the push cs */
pPatchRec->patch.flags &= ~(PATMFL_GUEST_SPECIFIC); /* prevent a breakpoint from being triggered */
return patmR3PatchInstrInt3(pVM, pInstrGC, pInstrHC, pCpu, &pPatchRec->patch);
}
/**
* Install guest OS specific patch
*
* @returns VBox status code.
* @param pVM The cross context VM structure.
* @param pCpu Disassembly state of instruction.
* @param pInstrGC GC Instruction pointer for instruction
* @param pInstrHC GC Instruction pointer for instruction
* @param pPatchRec Patch structure
*
*/
int patmR3InstallGuestSpecificPatch(PVM pVM, PDISCPUSTATE pCpu, RTGCPTR32 pInstrGC, uint8_t *pInstrHC, PPATMPATCHREC pPatchRec)
{
int rc;
/** @todo might have to check if the patch crosses a page boundary. Currently not necessary, but that might change in the future!! */
switch (pCpu->pCurInstr->uOpcode)
{
case OP_SYSENTER:
pPatchRec->patch.flags |= PATMFL_SYSENTER_XP | PATMFL_USER_MODE | PATMFL_GUEST_SPECIFIC;
rc = PATMPatchSysenterXP(pVM, pInstrGC, pPatchRec);
if (RT_FAILURE(rc))
{
return VERR_PATCHING_REFUSED;
}
return VINF_SUCCESS;
case OP_PUSH:
/* OpenBSD guest specific patch for the following code block:
*
* pushf
* push cs <- dangerous because of DPL 0 tests
* push esi
* cli
*/
if (pCpu->pCurInstr->fParam1 == OP_PARM_REG_CS)
return PATMPatchOpenBSDHandlerPrefix(pVM, pCpu, pInstrGC, pInstrHC, pPatchRec);
return VERR_PATCHING_REFUSED;
default:
AssertMsgFailed(("PATMInstallGuestSpecificPatch: unknown opcode %d\n", pCpu->pCurInstr->uOpcode));
return VERR_PATCHING_REFUSED;
}
}
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