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View Full Version : Kgm1 crackme - gdb segmentation fault


Xgrzyb90
October 25th, 2010, 01:59
By debugging kgm1 crackme from: http://www.crackmes.de/users/ascii/kgm1/ site, I encountered on such a problem. When I'm trying to debug crackme with gdb (anything else I'm not trying - I'm on linux), debugger shows segmentation fault.

Quote:

tomasz@darkstar:~/Pobrane/kgm1/ascii_kgm1$ objdump -d --section .text -M intel kgm1 | head -n 20

kgm1: file format elf32-i386


Disassembly of section .text:

08048380 <.text>:
8048380: 31 ed xor ebp,ebp
8048382: 5e pop esi
8048383: 89 e1 mov ecx,esp
8048385: 83 e4 f0 and esp,0xfffffff0
8048388: 50 push eax
8048389: 54 push esp
804838a: 52 push edx
804838b: 68 ec 84 04 08 push 0x80484ec
8048390: 68 f1 84 04 08 push 0x80484f1
8048395: 51 push ecx
8048396: 56 push esi
8048397: 68 22 84 04 08 push 0x8048422
804839c: e8 a7 ff ff ff call 8048348 <__libc_start_main@plt>


So I'm asking what I'm doing wrong.

I'm setting breakpoint on entrypoint and it shows error on push eax

disavowed
October 25th, 2010, 09:00
If "push eax" is throwing a segmentation fault then it means that the value of ESP is bad.