www.pudn.com > schddog.zip > ZKPASS.ASM

data segment at 0h 
     org 9h*4 
     KeyboardInt dd ? 
     org 13H*4 
     DiskInt dd ? 
     org 50H*4 
     HDInt dd ? 
     org 3f0h 
     ProSeg dw ? 
     org 413h 
     Memory_size dw ? 
     org 7C00H 
Boot proc far 
Boot endp 
data ends 
code segment 
     assume cs:code,ds:data 
     org 0h 
Head: 
     jmp start 
     RealInt label dword 
     RealOFF dw 0a189h 
     RealCS  dw 0f000h 
start: 
     cli 
     mov ax,cs 
     mov ds,ax 
     mov es,ax 
     mov ss,ax 
     mov sp,7C00h 
     xor si,si 
     sti 
     dec [memory_size] 
     dec [memory_size] 
     mov ax,[memory_size] 
     mov cl,6 
     shl ax,cl 
     mov es,ax 
     mov di,0 
     mov si,7c00h 
     mov cx,200h 
     rep movsb 
     push es 
     mov ax,offset continue 
     push ax 
     retf 
continue: 
     xor ax,ax 
     mov ds,ax 
     mov [ProSeg],es 
     cli 
     mov ax,word ptr [DiskInt] 
     mov word ptr cs:[RealOFF],ax 
     mov word ptr [HDInt],ax 
     mov ax,word ptr [DiskInt+2] 
     mov word ptr cs:[RealCS],ax 
     mov word ptr [HDInt+2],ax 
      
     mov ax,offset Int_Handler 
     mov word ptr [DiskInt],ax 
     mov word ptr [DiskInt+2],cs 
      
     mov ax,word ptr [KeyboardInt] 
     mov word ptr cs:[OldInt9],ax 
     mov ax,word ptr [KeyboardInt+2] 
     mov word ptr cs:[OldInt9+2],ax 
     mov ax,offset Int9_Handler 
     mov word ptr [KeyboardInt],ax 
     mov word ptr [KeyboardInt+2],cs 
      
     mov si,0002h 
$CheckBoot: 
     mov ax,0201h 
     mov bx,0200h 
     mov cx,0001h 
     mov dx,0080h 
     pushf 
     call dword ptr Realint 
     jnb $4 
     dec si 
     jnz $CheckBoot 
$4: 
     xor si,si 
     mov di,200h 
     push cs 
     pop ds 
     repe cmpsb 
     jz $Right 
     mov si,offset Virus_IN 
     xor ch,ch 
     lodsb 
     mov cl,al 
     mov ax,1301h 
     mov bx,7 
     sub dx,dx 
     mov bp,si 
     int 10h 
$Right: 
     mov ax,cs 
     mov es,ax 
     xor bx,bx 
     mov ax,0301h 
     mov cx,0001h 
     mov dx,0080h 
     pushf 
     call dword ptr Realint 
     mov si,0002h 
$ReadPass: 
     mov ax,0203h 
     mov bx,0200h 
     mov cx,0004h 
     mov dx,0080h 
     pushf 
     call dword ptr RealInt 
     jnb $1 
     dec si 
     jnz $ReadPass 
$1: 
     mov ax,offset $J1 
     push ax 
     mov ax,0200h 
     push ax 
     ret 
$J1: 
     sti 
     xor ax,ax 
     mov es,ax 
     mov si,0002h 
$ReadBoot: 
     mov ax,0201h 
     mov bx,7c00h 
     mov cx,0003h 
     mov dx,0080h 
     pushf 
     call dword ptr RealInt 
     jnb $2 
     dec si 
     jnz $ReadBoot 
$2: 
     jmp boot 
      
     OldInt9 dd ? 
     Virus_IN db VirusLen,'[Virus] Self Protect...',0ah,0dh 
     VirusLen equ ($-Virus_IN)-1 
     Priority db 00h 
              db 0ffh,0ffh 
     Cyl dw 619 
     Hotkey equ 1 
     Shift_Mask equ 00001010b 
Int_Handler: 
     sti 
     cmp dx,0080h 
     jne @01 
     cmp cx,0001h 
     jne @01 
     mov cx,0003h 
@01:  
     cmp ah,03h 
     jz check 
     cmp ah,05h 
     jz check 
     cmp ah,06h 
     jz check 
     cmp ah,07h 
     jz check 
     cmp ah,0bh 
     jz check 
     cmp ah,0fh 
     jz check 
     cmp ah,13h 
     jz check 
     cmp ah,19h 
     jz check 
Conti: 
     jmp cs:[RealInt] 
check: 
     cmp dl,80h 
     jne conti 
     push cx 
     push dx 
     xchg ch,cl 
     and ch,11000000b 
     mov dx,cx 
     mov cl,6 
     shr dh,cl 
     cmp dx,word ptr Cyl 
     pop dx 
     pop cx 
     jge conti 
     cmp cs:Priority,00h 
     je Error 
     cmp dh,00h 
     jne conti 
     cmp cx,0001h 
     jz Error 
     cmp cx,0002h 
     jz Error 
     cmp cx,0003h 
     jz Error 
     cmp cx,0007h 
     jz Error 
     cmp cx,0008h 
     jz Error 
     jmp conti 
Error: 
     mov ah,00h 
     std 
     retf 2 
Int9_Handler: 
     sti 
     push ax 
     in al,60h 
     cmp al,Hotkey 
     je Trigger 
Int9_Exit: 
     pop ax 
     jmp cs:[OldInt9] 
Trigger: 
     mov ah,2 
     int 16h 
     and al,0fh 
     cmp al,Shift_Mask 
     jnz Int9_Exit 
     pushf 
     call cs:[OldInt9] 
     pushf 
     mov ax,offset @j2 
     push ax 
     mov ax,600h 
     push ax 
     ret 
@j2: 
     jc $lock 
     mov cs:Priority,0ffh 
     jmp @j3 
$lock: 
     mov cs:Priority,00h 
@j3: 
     popf 
     pop ax 
     iret                     
Tail: 
     Filler_Amount equ 512-(Tail-Head)-2 
     db Filler_Amount dup(0) 
     dw 0AA55h 
code ends 
     end