Base64 pour Linux x32
format ELF executable 3
entry start
include 'include/linux/lin32a.inc'
include 'base64.inc'
interpreter '/lib/ld-linux.so.2'
needed 'libc.so.6'
import printf
;-------------------------------------------------------------------------
segment readable executable
;-------------------------------------------------------------------------
start:
mov edx,S_IRU
mov ecx,O_RD
mov ebx,fpath1
mov eax,_open
int 0x80
mov [fd1],eax
mov edx,S_IRWU
mov ecx,O_CREAT or O_RDWR
mov ebx,fpath2
mov eax,_open
int 0x80
mov [fd2],eax
mov ecx,statbuf
mov ebx,fpath1
mov eax,_stat
int 0x80
mov edx,dword [statbuf+20]
mov ecx,readbuf
mov ebx,[fd1]
mov eax,_read
int 0x80
stdcall cBase64,readbuf,writebuf,writebuflen
; stdcall dBase64,readbuf,writebuf,writebuflen
mov edx,[writebuflen]
mov ecx,writebuf
mov ebx,[fd2]
mov eax,_write
int 0x80
xor ebx,ebx
mov eax,_exit
int 0x80
;-------------------------------------------------------------------------
segment readable writeable
;-------------------------------------------------------------------------
fd1 dd 0
fd2 dd 0
fpath1 db 'test.txt',0
fpath2 db 'file64.txt',0
;fpath1 db 'file64.txt',0
;fpath2 db 'test.txt',0
statbuf rb 144
readbuf rb 1024
writebuf rb 1024
writebuflen dd 0;-------------------------------------------------------------------------
segment readable executable
;-------------------------------------------------------------------------
proc cBase64 inbuf,outbuf,outbuflen
mov esi,[inbuf]
mov edi,[outbuf]
mov ecx,[outbuflen]
@re:
or byte [esi],0
jz @end
add dword [ecx],4
xor eax,eax
or byte [esi+2],0
jz @f
mov al,byte [esi]
inc esi
ror eax,8
mov ax,word [esi]
add esi,2
bswap eax
call Encode
mov dword [edi],eax
add edi,4
jmp @re
@@:
or byte [esi+1],0
jz @f
mov ax,word [esi]
add esi,2
ror ax,8
ror eax,8
call Encode
rol eax,8
mov al,0x3d
ror eax,8
mov dword [edi],eax
add edi,4
jmp @re
@@:
mov al,byte [esi]
inc esi
call Encode
rol eax,16
mov ax,0x3d3d
ror eax,16
mov dword [edi],eax
add edi,4
jmp @re
@end:
ret
endp
proc Encode
push ecx
xor ecx,ecx
mov cl,4
@@:
xor ebx,ebx
mov bl,al
shr bl,2
rol eax,6
mov dl,byte [base64+ebx]
ror edx,8
dec cl
jnz @b
mov eax,edx
pop ecx
ret
endp
proc dBase64 inbuf,outbuf,outbuflen
mov esi,[inbuf]
mov edi,[outbuf]
mov ecx,[outbuflen]
@re:
or byte [esi],0
jz @end
or byte [esi+1],0
jz @end
cmp byte [esi+3],0x3d
jz @f
add dword [ecx],3
call Decode
mov word [edi],ax
add edi,2
ror eax,16
mov byte [edi],al
inc edi
jmp @re
@@:
cmp byte [esi+2],0x3d
jz @f
mov byte [esi+3],0
add dword [ecx],2
call Decode
mov word [edi],ax
add edi,2
jmp @re
@@:
mov byte [esi+2],0
add dword [ecx],1
call Decode
mov byte [edi],al
inc edi
jmp @re
@end:
ret
endp
proc Decode
push ecx
mov cl,4
@@:
mov al,byte [esi]
inc esi
call strlen
shl dl,2
mov al,dl
shr eax,2
shl eax,8
dec cl
jnz @b
bswap eax
pop ecx
ret
endp
proc strlen
push edi
push ecx
xor ecx,ecx
mov edi,base64
@@:
inc ecx
inc edi
cmp al,byte [edi]
jnz @b
mov dl,cl
pop ecx
pop edi
ret
endp
base64 db 0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,\
0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f,0x50,\
0x51,0x52,0x53,0x54,0x55,0x56,0x57,0x58,\
0x59,0x5a,0x61,0x62,0x63,0x64,0x65,0x66,\
0x67,0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,\
0x6f,0x70,0x71,0x72,0x73,0x74,0x75,0x76,\
0x77,0x78,0x79,0x7a,0x30,0x31,0x32,0x33,\
0x34,0x35,0x36,0x37,0x38,0x39,0x2b,0x2f,0A compiler avec Fasm
