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05_ELF_hooking fails to work well #2

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deathmemory opened this issue Jul 12, 2018 · 7 comments
Closed

05_ELF_hooking fails to work well #2

deathmemory opened this issue Jul 12, 2018 · 7 comments

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@deathmemory
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$ cd 05_ELF_infect_plt-got/
$ make
gcc crackme.c -O3 -o crackme.bin
chmod u+rx crackme.bin
gcc -nostdlib -nodefaultlibs -fPIC -Wl,-shared hook.c -o hook
In file included from hook.c:1:0:
arch/x86_64/syscall.c:24:13: warning: conflicting types for built-in function ‘_exit’ [-Wbuiltin-declaration-mismatch]
 static long _exit(int errcode) {
             ^~~~~
$ python hook_pltgot.py 
$ ./crackme.hooked XXXXXXXXXXXXXXXXXXXXX
Wrong

my OS:

$ uname -a
Linux ubuntu 4.15.0-20-generic #21-Ubuntu SMP Tue Apr 24 06:16:15 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

LIEF version: 0.9.0

I found the segment has to added to the crackme.hooked and the .got address has been changed exactly.
But when it runs, the correct value will be changed back.
it still calls memcmp from libc

Please help
@romainthomas
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Does make run fail ?

@deathmemory
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Yes , it says that

$ make run
python ./hook_pltgot.py
chmod u+x ./crackme.hooked
./crackme.hooked XXXXXXXXXXXXXXXXXXXXX
Wrong
make: *** [run] Error 1

@romainthomas
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could you attach your compiled crackme.bin and crackme.hooked ?

@deathmemory
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yes i can

@romainthomas
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I mean upload it on this github issue

@deathmemory
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OK ~

05_bin_hook.zip

@deathmemory
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It works now , thank you ! 👍

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2 participants
@deathmemory @romainthomas