180 lines
4.7 KiB
NASM
180 lines
4.7 KiB
NASM
; l_exe.asm -- loader & decompressor for the dos/exe format
|
|
;
|
|
; This file is part of the UPX executable compressor.
|
|
;
|
|
; Copyright (C) 1996-2000 Markus Franz Xaver Johannes Oberhumer
|
|
; Copyright (C) 1996-2000 Laszlo Molnar
|
|
; All Rights Reserved.
|
|
;
|
|
; UPX and the UCL library are free software; you can redistribute them
|
|
; and/or modify them under the terms of the GNU General Public License as
|
|
; published by the Free Software Foundation; either version 2 of
|
|
; the License, or (at your option) any later version.
|
|
;
|
|
; This program is distributed in the hope that it will be useful,
|
|
; but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
; GNU General Public License for more details.
|
|
;
|
|
; You should have received a copy of the GNU General Public License
|
|
; along with this program; see the file COPYING.
|
|
; If not, write to the Free Software Foundation, Inc.,
|
|
; 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
;
|
|
; Markus F.X.J. Oberhumer Laszlo Molnar
|
|
; markus.oberhumer@jk.uni-linz.ac.at ml1050@cdata.tvnet.hu
|
|
;
|
|
|
|
|
|
%define EXE
|
|
%define jmps jmp short
|
|
%define jmpn jmp near
|
|
|
|
BITS 16
|
|
ORG 0
|
|
SECTION .text
|
|
|
|
; =============
|
|
; ============= ENTRY POINT
|
|
; =============
|
|
; __EXEENTRY__
|
|
mov cx, 'CX' ; first_copy_len/2
|
|
mov si, 'SI' ; cx*2-2
|
|
mov di, si
|
|
push ds
|
|
db 0xa9
|
|
do_copy:
|
|
mov ch, 0x80 ; 64 kbyte
|
|
mov ax, cs
|
|
add ax, 'DS'
|
|
mov ds, ax
|
|
add ax, 'ES'
|
|
mov es, ax
|
|
|
|
std
|
|
rep
|
|
movsw
|
|
cld
|
|
|
|
sub [byte cs:si+do_copy+6+2], byte 0x10
|
|
jnc do_copy
|
|
xchg ax, dx
|
|
scasw
|
|
lodsw
|
|
%ifdef __EXERELPU__
|
|
push cs
|
|
%endif; __EXEMAIN4__
|
|
push cs
|
|
push cs
|
|
push es
|
|
pop ds
|
|
pop es
|
|
push ss
|
|
mov bp, 'BP' ; entry point [0x1,0x10]
|
|
mov bx, 'BX' ; 0x800F + 0x10*bp - 0x10
|
|
push bp
|
|
retf
|
|
|
|
%include "header.ash"
|
|
|
|
; __EXECUTPO__
|
|
|
|
; =============
|
|
; ============= DECOMPRESSION
|
|
; =============
|
|
|
|
%include "n2b_d8e.ash"
|
|
%include "n2d_d8e.ash"
|
|
|
|
; =============
|
|
; ============= RELOCATION
|
|
; =============
|
|
; __EXEMAIN5__
|
|
pop bp
|
|
%ifdef __EXERELOC__
|
|
%ifdef __EXEADJUS__
|
|
mov ax, es
|
|
sub ah, 0x6 ; MAXRELOCS >> 12
|
|
mov ds, ax
|
|
%else; __EXENOADJ__
|
|
push es
|
|
pop ds
|
|
%endif; __EXERELO1__
|
|
lea si, [di+'RS']
|
|
lodsw
|
|
|
|
pop bx
|
|
|
|
xchg ax, cx ; number of 0x01 bytes (not exactly)
|
|
lodsw
|
|
xchg ax, dx ; seg_hi
|
|
reloc_0:
|
|
lodsw
|
|
xchg ax, di
|
|
lodsw
|
|
add bx, ax
|
|
mov es, bx
|
|
xor ax, ax
|
|
reloc_1:
|
|
add di, ax
|
|
add [es:di], bp
|
|
reloc_2:
|
|
lodsb
|
|
dec ax
|
|
jz reloc_5
|
|
inc ax
|
|
jnz reloc_1
|
|
%ifdef __EXEREL9A__
|
|
inc di
|
|
reloc_4:
|
|
inc di
|
|
cmp byte [es:di], 0x9a
|
|
jne reloc_4
|
|
cmp [es:di+3], dx
|
|
ja reloc_4
|
|
mov al, 3
|
|
jmps reloc_1
|
|
%endif; __EXERELO2__
|
|
reloc_5:
|
|
add di, 0xfe
|
|
%ifdef __EXEREBIG__
|
|
jc reloc_0
|
|
%endif; __EXERELO3__
|
|
loop reloc_2
|
|
%endif; __EXEMAIN8__
|
|
|
|
; =============
|
|
|
|
pop es
|
|
push es
|
|
pop ds
|
|
%ifdef __EXESTACK__
|
|
lea ax, ['SS'+bp]
|
|
mov ss, ax
|
|
%endif; __EXEDUMMS__
|
|
%ifdef __EXESTASP__
|
|
mov sp, 'SP'
|
|
%endif; __EXEDUMMP__
|
|
|
|
; =============
|
|
|
|
%ifdef __EXEJUMPF__
|
|
jmp 'CS':'IP'
|
|
%else; __EXERETUR__
|
|
%ifdef __EXERCSPO__
|
|
add bp, 'CS'
|
|
%endif; __EXERETIP__
|
|
push bp
|
|
mov ax, 'IP'
|
|
push ax
|
|
retf
|
|
%endif; __EXEDUMMZ__
|
|
eof:
|
|
; __EXETHEND__
|
|
section .data
|
|
dd -1
|
|
dw eof
|
|
|
|
|
|
; vi:ts=8:et:nowrap
|