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Index > Linux > mmx segment fault !?

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catafest



Joined: 05 Aug 2010
Posts: 122
catafest
Hi , can you tell me what is wrong with my source code ?
Thank you . Regards
Code:
use32
format ELF executable 3
entry start
segment readable executable
start:
        call mmxtest
mmxtest:
        push ebx
        push ecx
        push edx
        mov eax,1
        cpuid
        mov eax,edx
        shr eax,23
        and eax,1
        pop edx
        pop ecx
        pop ebx
        ret
segment readable writeable
align 4    
Post 16 Apr 2013, 22:00
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randall



Joined: 03 Dec 2011
Posts: 155
Location: Poland
randall
You have to call sys_exit syscall after 'call mmxtest'.
Post 16 Apr 2013, 22:26
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HaHaAnonymous



Joined: 02 Dec 2012
Posts: 1180
Location: Unknown
HaHaAnonymous
[ Post removed by author. ]


Last edited by HaHaAnonymous on 28 Feb 2015, 21:02; edited 1 time in total
Post 16 Apr 2013, 22:40
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catafest



Joined: 05 Aug 2010
Posts: 122
catafest
$ ./fasm mmm.asm
flat assembler version 1.70.03 (16384 kilobytes memory)
mmm.asm [5]:
here
error: illegal instruction.
Post 25 Jun 2013, 14:06
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17716
Location: In your JS exploiting you and your system
revolution
Show your source code please.
Post 25 Jun 2013, 14:33
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Madis731



Joined: 25 Sep 2003
Posts: 2140
Location: Estonia
Madis731
Code:
use32
format ELF executable 3
entry start
segment readable executable

start: 
        ; program entry point. OK!
        call mmxtest
        ; after calling "mmxtest" it will return here, so put an end here
        ; param1 in ebx (0)
        xor ebx,ebx
        ; syscall number in eax (1 = sys_exit)
        mov eax,$00000001
        ; int $80, call kernel function (it won't return, program terminates)
        int $80
        ; no more execution after this
mmxtest:
        push ebx 
        push ecx 
        push edx 
        mov eax,1 
        cpuid 
        mov eax,edx 
        shr eax,23 
        and eax,1 
        pop edx 
        pop ecx 
        pop ebx 
        ret
    

flat assembler version 1.71.10 (16384 kilobytes memory)
2 passes, 120 bytes.
FDBG shows that eax resolves to 1
Post 25 Jun 2013, 16:41
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