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Index > Windows > Need help about SEH.

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Overflowz



Joined: 03 Sep 2010
Posts: 1046
Overflowz
Hi, I'm learning SEH things and I'm bit stuck on it.. I have some questions and can anybody help me with it ?
1) How SEH works ?
2) How can I initialize SEH chain ?

I have written little proggy here but I don't understand alot from there Smile
Code:
proc main
     push msgbox
     push dword [fs:0]
     mov [fs:0],esp
     mov eax,0
     mov eax,[eax]
     ret
endp

proc msgbox
invoke MessageBox,0,msg,ttl,MB_OK+MB_ICONINFORMATION
jmp fixa
ret
endp

proc fixa
invoke MessageBox,0,msg1,ttl,MB_OK+MB_ICONINFORMATION
ret
endp    

I found some example on web and trying to understand things..
I'm pushing procedure which will occured when exception will happen, after that pushing [fs:0] which is SEH I guess and then moving ESP (SEH address) to [fs:0] but I don't understand why... Also, I'm trying to not destroy stack but after adding these instructions forward from mov [fs:0],esp and then add esp,8 - exception says can't read address from 00000..
Can someone explain me how to do it without destroying stack and how it works ? Thank you.. Smile
Post 01 Jul 2011, 20:07
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vid
Verbosity in development


Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia
vid
Internet is full of SEH tutorials, did you try following one?
Post 02 Jul 2011, 08:11
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Overflowz



Joined: 03 Sep 2010
Posts: 1046
Overflowz
Yes, I already tried but I don't understand a lot from there.
P.S First of all, I'm trying to find something in google and if nothing useful found, I'm posting here..
If you know better tutorial, can you give me link ? Thanks.
Post 02 Jul 2011, 08:18
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