我原本不想问的(不敢),毕竟，我是一名小菜鸟，但是，我在苦苦挣扎了半天以后，确实没则了,故请你们那位朋友帮我理解一下下面的几句代码，感激不尽.
对于你们这些大牛来说，一定非常简单，请不要笑话我哈.
我先上全部代码.
;Inline Hook NtOpenFile 简单实现保护指定路径文件
.386
.model flat,stdcall
option casemap:none
;头文件声明;
include \masm32\include\w2k\ntstatus.inc
include \masm32\include\w2k\ntddk.inc
include \masm32\include\w2k\hal.inc
include \masm32\include\w2k\ntoskrnl.inc
includelib \masm32\lib\w2k\ntoskrnl.lib
includelib \masm32\lib\w2k\hal.lib
include \masm32\Macros\Strings.mac
;数据段;
.data
OldNtOpenFile proto :DWORD,:DWORD,:DWORD,:DWORD,:DWORD,:DWORD ;声明函数体;
NtOpenFile_Addr dd ? ;保存NtOpenFile的真实地址;
oldIrql dd ? ;保存IRQL;
szName UNICODE_STRING <?> ;文件名(UNICODE);
uCmdPathName dw '\','?','?','\','C',':','\','W','I','N','D','O','W','S','\','S','Y','S','T','E','M','3','2','\','c','m','d','.','e','x','e',0 ;欲保护文件的绝对路径(此CMD为例);
;代码段;
.code
DriverUnload proc pDriverObject:PDRIVER_OBJECT ;驱动卸载函数(start);
pushad
cli
mov eax, cr0 ;将CR0的WP(Write Protect)写保护置0->关闭写保护;
and eax,0fffeffffh
mov cr0, eax
invoke KeRaiseIrqlToDpcLevel ;提升中断级,返回值:KeRaiseIrqlToDpcLevel returns the IRQL at which the call occurred;
mov oldIrql,eax ;将返回值保存在oldIrpl中;
mov ecx,5
mov edi,NtOpenFile_Addr
mov esi,offset OldNtOpenFile
rep movsb
invoke KeLowerIrql,oldIrql ;降低中断级;
mov eax, cr0 ;恢复只读页写保护;
or eax,10000h
mov cr0, eax
sti
popad
ret
DriverUnload endp
OldNtOpenFile proc FileHandle,DesiredAccess,ObjectAttributes,IoStatusBlock,ShareAccess,OpenOptions
nop
nop
mov eax,NtOpenFile_Addr
add eax,5
jmp eax
OldNtOpenFile endp
MyNtOpenFile proc FileHandle,DesiredAccess,ObjectAttributes,IoStatusBlock,ShareAccess,OpenOptions
mov eax,ObjectAttributes
assume eax:ptr OBJECT_ATTRIBUTES
invoke RtlCompareUnicodeString ,[eax].ObjectName,offset szName,TRUE ;比较字符串(UNICODE);
.if eax == 0
mov eax,STATUS_ACCESS_DENIED
ret
.endif
assume eax:nothing
invoke OldNtOpenFile,FileHandle,DesiredAccess,ObjectAttributes,IoStatusBlock,ShareAccess,OpenOptions
ret
MyNtOpenFile endp
DriverEntry proc pDriverObject:PDRIVER_OBJECT,pRegistryPath:PUNICODE_STRING ;多么熟悉,驱动的入口函数,相当于win32的main;
pushad
invoke RtlInitUnicodeString,offset szName,offset uCmdPathName ;初始化UNICODE字符;
cli
mov eax, cr0 ;去掉只读页写保护;
and eax,0fffeffffh
mov cr0, eax
invoke KeRaiseIrqlToDpcLevel ;提升中断级;
mov oldIrql,eax
invoke MmGetSystemRoutineAddress,$CCOUNTED_UNICODE_STRING("NtOpenFile") ;直接调用MmGetSystemRoutineAddress获取已经导出的内核函数地址;
mov NtOpenFile_Addr,eax
mov ecx,5 ;计数寄存器置5(传送5个字节);
mov esi,eax
mov edi,offset OldNtOpenFile
rep movsb
mov edx,offset MyNtOpenFile
sub edx,eax
sub edx,5
mov byte ptr [eax],0e9h
xchg [eax+1],edx
invoke KeLowerIrql,oldIrql ;恢复中断级;
mov eax, cr0 ;去掉只读页写保护;
or eax,10000h
mov cr0, eax
sti
mov eax,pDriverObject
assume eax:ptr DRIVER_OBJECT
mov [eax].DriverUnload,offset DriverUnload
assume eax:nothing
popad
mov eax,STATUS_SUCCESS
ret
DriverEntry endp
end DriverEntry
以上就是全部代码了.
那么，那位朋友帮助我解释一下下面几句代码呢?谢谢.
在获取NtOpenFile的地址后:
mov NtOpenFile_Addr,eax
mov ecx,5
mov esi,eax
mov edi,offset OldNtOpenFile
rep movsb
mov edx,offset MyNtOpenFile
sub edx,eax
sub edx,5
mov byte ptr [eax],0e9h
xchg [eax+1],edx
谢谢哈，我在线等.一定要帮我哈.
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