枚举与删除注册表回调
注册表回调是一个监控注册表读写的回调，它的效果非常明显，一个回调能实现在SSDT 上 HOOK 十几个 API 的效果。部分游戏保护还会在注册表回调上做功夫，监控 service
键的子键，实现双层拦截驱动加载（在映像回调那里还有一层）。而在卡巴斯基等 HIPS 类软件里，则用来监控自启动等键值。
注册表回调在 XP 系统上貌似是一个数组，但是从 WINDOWS 2003 开始，就变成了一个链表。这个链表的头称为 CallbackListHead，可在 CmUnRegisterCallback 中找到：
搜索的过程跟寻找进程、线程、映像的数组类似，根据 lea REG,XXX 来定位。不过为了更加精准，这次资料中是采用两次 lea REG,XXX 来定位：
ULONG64 FindCmpCallbackAfterXP()
{
ULONG64 uiAddress=0;
PUCHAR pCheckArea=NULL, i=0, j=0, StartAddress=0, EndAddress=0;
ULONG64 dwCheckAddr=0;
UNICODE_STRING unstrFunc;
UCHAR b1=0,b2=0,b3=0;
ULONG templong=0,QuadPart=0xfffff800;
RtlInitUnicodeString(&unstrFunc, L"CmUnRegisterCallback");
pCheckArea = (UCHAR*)MmGetSystemRoutineAddress (&unstrFunc) ;
if (!pCheckArea)
{
KdPrint(("MmGetSystemRoutineAddress failed."));
return 0;
}
StartAddress = (PUCHAR)pCheckArea;
EndAddress = (PUCHAR)pCheckArea + PAGE_SIZE;
for(i=StartAddress;i<EndAddress;i++)
{
if( MmIsAddressValid(i) && MmIsAddressValid(i+1) && MmIsAddressValid(i+2) )
{
b1=*i;
b2=*(i+1);
b3=*(i+2);
if( b1==0x48 && b2==0x8d && b3==0x0d ) //488d0d(lea rcx,)
{
j=i-5;
b1=*j;
b2=*(j+1);
b3=*(j+2);
if( b1==0x48 && b2==0x8d && b3==0x54 ) //488d54(lea rdx,)
{
memcpy(&templong,i+3,4);
uiAddress = MakeLong64ByLong32(templong) + (ULONGLONG)i + 7;
return uiAddress;
}
}
}
}
return 0;
}定位完毕之后，就是枚举链表了。注册表回调是一个“结构体链表”，类似于 EPROCESS，它的定义如下：
typedef struct _CM_NOTIFY_ENTRY
{
LIST_ENTRY ListEntryHead;
ULONG UnKnown1;
ULONG UnKnown2;
LARGE_INTEGER Cookie;
ULONG64 Context;
ULONG64 Function;
}CM_NOTIFY_ENTRY, *PCM_NOTIFY_ENTRY;
我们只关心两个值，一个是 Cookie，一个是 Function。前者可以理解成注册表回调的“句柄”（用 CmUnRegisterCallback 注销回调传入的就是这个 Cookie），后者是回调函数的地址。代码如下：
ULONG CountCmpCallbackAfterXP(ULONG64* pPspLINotifyRoutine)
{
ULONG sum = 0;
ULONG64 dwNotifyItemAddr;
ULONG64* pNotifyFun;
ULONG64* baseNotifyAddr;
ULONG64 dwNotifyFun;
LARGE_INTEGER cmpCookie;
PLIST_ENTRY notifyList;
PCM_NOTIFY_ENTRY notify;
dwNotifyItemAddr = *pPspLINotifyRoutine;
notifyList = (LIST_ENTRY *)dwNotifyItemAddr;
do
{
notify = (CM_NOTIFY_ENTRY *)notifyList;
if (MmIsAddressValid(notify))
{
if (MmIsAddressValid((PVOID)(notify->Function)) && notify->Function > 0x8000000000000000)
{
DbgPrint("[CmCallback]Function=%p Cookie=%p", (PVOID)(notify->Function),(PVOID)(notify->Cookie.QuadPart));
//notify->Function=(ULONG64)MyRegistryCallback;
sum ++;
}
}
notifyList = notifyList->Flink;
}while ( notifyList != ((LIST_ENTRY*)(*pPspLINotifyRoutine)) );
return sum;
}
执行效果（在有360的机器上执行的）：
对付注册表回调有三种方法：
1.直接使用CmUnRegisterCallback 把回调注销；
2.把链表中记录的回调地址修改为自定义的空函数的回调地址；
3.直接在目标回调地址上写一个 RET，使其不执行任何代码就返回。 第三种 方法 没有针对性，可以用于对付 任何 回调函数。DisableFunctionWithReturnValue 用来对付有返回值的回调函数，DisableFunctionWithoutReturnValue 用于对付无返回值的回调函数。
/*
给函数头写RET废除函数功能，这份代码可以用于对抗任意回调函数，但仅限于WIN64系统。
DisableFunctionWithReturnValue用于有返回值的回调
DisableFunctionWithoutReturnValue用于无返回值的回调
*/
KIRQL WPOFFx64()
{
KIRQL irql=KeRaiseIrqlToDpcLevel();
UINT64 cr0=__readcr0();
cr0 &= 0xfffffffffffeffff;
__writecr0(cr0);
_disable();
return irql;
}
void WPONx64(KIRQL irql)
{
UINT64 cr0=__readcr0();
cr0 |= 0x10000;
_enable();
__writecr0(cr0);
KeLowerIrql(irql);
}
VOID DisableFunctionWithReturnValue(PVOID Address)
{
KIRQL irql;
CHAR patchCode[] = "x33xC0xC3"; //xor eax,eax + ret
if(MmIsAddressValid(Address))
{
irql=WPOFFx64();
memcpy(Address,patchCode,3);
WPONx64(irql);
}
}
VOID DisableFunctionWithoutReturnValue(PVOID Address)
{
KIRQL irql;
if(MmIsAddressValid(Address))
{
irql=WPOFFx64();
RtlFillMemory(Address,1,0xC3);
WPONx64(irql);
}
}代码备份：win7 X64
typedef struct _CM_NOTIFY_ENTRY
{
LIST_ENTRY ListEntryHead;
ULONG UnKnown1;
ULONG UnKnown2;
LARGE_INTEGER Cookie;
ULONG64 Context;
ULONG64 Function;
}CM_NOTIFY_ENTRY, *PCM_NOTIFY_ENTRY;
LARGE_INTEGER Cookie;
ULONG64 CmCallbackListHead=0;
NTSTATUS MyRegistryCallback(
IN PVOID CallbackContext,
IN PVOID Argument1,
IN PVOID Argument2
)
{
return STATUS_SUCCESS;
}
ULONG CountCmpCallbackAfterXP(ULONG64* pPspLINotifyRoutine)
{
ULONG sum = 0;
ULONG64 dwNotifyItemAddr;
ULONG64* pNotifyFun;
ULONG64* baseNotifyAddr;
ULONG64 dwNotifyFun;
LARGE_INTEGER cmpCookie;
PLIST_ENTRY notifyList;
PCM_NOTIFY_ENTRY notify;
dwNotifyItemAddr = *pPspLINotifyRoutine;
notifyList = (LIST_ENTRY *)dwNotifyItemAddr;
do
{
notify = (CM_NOTIFY_ENTRY *)notifyList;
if (MmIsAddressValid(notify))
{
if (MmIsAddressValid((PVOID)(notify->Function)) && notify->Function > 0x8000000000000000)
{
DbgPrint("[CmCallback]Function=%p Cookie=%p", (PVOID)(notify->Function),(PVOID)(notify->Cookie.QuadPart));
//notify->Function=(ULONG64)MyRegistryCallback;
sum ++;
}
}
notifyList = notifyList->Flink;
}while ( notifyList != ((LIST_ENTRY*)(*pPspLINotifyRoutine)) );
return sum;
}
LONG64 MakeLong64ByLong32(LONG lng32)
{
LONG64 lng64=0;
if(lng32>0)
{
lng64=(LONG64)lng32;
}
else
{
lng64=0xffffffffffffffff;
memcpy(&lng64,&lng32,4);
}
return lng64;
}
ULONG64 FindCmpCallbackAfterXP()
{
ULONG64 uiAddress=0;
PUCHAR pCheckArea=NULL, i=0, j=0, StartAddress=0, EndAddress=0;
ULONG64 dwCheckAddr=0;
UNICODE_STRING unstrFunc;
UCHAR b1=0,b2=0,b3=0;
ULONG templong=0,QuadPart=0xfffff800;
RtlInitUnicodeString(&unstrFunc, L"CmUnRegisterCallback");
pCheckArea = (UCHAR*)MmGetSystemRoutineAddress (&unstrFunc) ;
if (!pCheckArea)
{
KdPrint(("MmGetSystemRoutineAddress failed."));
return 0;
}
StartAddress = (PUCHAR)pCheckArea;
EndAddress = (PUCHAR)pCheckArea + PAGE_SIZE;
for(i=StartAddress;i<EndAddress;i++)
{
if( MmIsAddressValid(i) && MmIsAddressValid(i+1) && MmIsAddressValid(i+2) )
{
b1=*i;
b2=*(i+1);
b3=*(i+2);
if( b1==0x48 && b2==0x8d && b3==0x0d ) //488d0d(lea rcx,)
{
j=i-5;
b1=*j;
b2=*(j+1);
b3=*(j+2);
if( b1==0x48 && b2==0x8d && b3==0x54 ) //488d54(lea rdx,)
{
memcpy(&templong,i+3,4);
uiAddress = MakeLong64ByLong32(templong) + (ULONGLONG)i + 7;
return uiAddress;
}
}
}
}
return 0;
}
void EnumCmCallback64()
{
//test to add my reg callback
CmRegisterCallback(MyRegistryCallback, NULL, &Cookie);
DbgPrint("[MY FUNCTION]: %p",(PVOID)MyRegistryCallback);
DbgPrint("[MY COOKIE]: %p",(PVOID)Cookie.QuadPart);
//get CmCallbackListHead address
CmCallbackListHead=FindCmpCallbackAfterXP();
DbgPrint("CmCallbackListHead: %p",(PVOID)CmCallbackListHead);
//enum callback address
CountCmpCallbackAfterXP((ULONG64*)CmCallbackListHead);
//unregister my callback
CmUnRegisterCallback(Cookie);
}
/*
给函数头写RET废除函数功能，这份代码可以用于对抗任意回调函数，但仅限于WIN64系统。
DisableFunctionWithReturnValue用于有返回值的回调
DisableFunctionWithoutReturnValue用于无返回值的回调
*/
KIRQL WPOFFx64()
{
KIRQL irql=KeRaiseIrqlToDpcLevel();
UINT64 cr0=__readcr0();
cr0 &= 0xfffffffffffeffff;
__writecr0(cr0);
_disable();
return irql;
}
void WPONx64(KIRQL irql)
{
UINT64 cr0=__readcr0();
cr0 |= 0x10000;
_enable();
__writecr0(cr0);
KeLowerIrql(irql);
}
VOID DisableFunctionWithReturnValue(PVOID Address)
{
KIRQL irql;
CHAR patchCode[] = "x33xC0xC3"; //xor eax,eax + ret
if(MmIsAddressValid(Address))
{
irql=WPOFFx64();
memcpy(Address,patchCode,3);
WPONx64(irql);
}
}
VOID DisableFunctionWithoutReturnValue(PVOID Address)
{
KIRQL irql;
if(MmIsAddressValid(Address))
{
irql=WPOFFx64();
RtlFillMemory(Address,1,0xC3);
WPONx64(irql);
}
}
宋孖健，13