[BUG] Stack overflow

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LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4624
Location: Argentina

LocoDelAssembly 30 Aug 2009, 17:33

Compiling the following code twice (re-opening the source first), will produce a stack overflow situation (not stack buffer overflow):

Code:

format binary as 'asm' ; Self destructible source :D

repeat 1000000
  ; db "(" ; This will make FASMW crash
  db "-" ; This crash FASMW and command line fasm
end repeat

[edit]Command line version also silently crash when "-" is used. I've changed the code to test for that and commented the "(" test.[/edit]

Last edited by LocoDelAssembly on 30 Aug 2009, 18:38; edited 1 time in total

30 Aug 2009, 17:33

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20413
Location: In your JS exploiting you and your system

revolution 30 Aug 2009, 17:45

fasm (command line version) is fine with that above code (I get 'error: out of stack space.')

At 100000000 I only get 'error: out of memory.'

At 1000 I get 'error: illegal instruction'

30 Aug 2009, 17:45

LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4624
Location: Argentina

LocoDelAssembly 30 Aug 2009, 18:29

Quote:

fasm (command line version) is fine with that above code (I get 'error: out of stack space.')

Yep, I almost posted this on Compilers Internals but after verifying this I posted here. Smile

BTW, that is just minimal example, but actually the same will happen if a very long chain of "(" or "-" is found in any expression.

30 Aug 2009, 18:29

Borsuc

Joined: 29 Dec 2005
Posts: 2465
Location: Bucharest, Romania

Borsuc 01 Sep 2009, 18:30

Is this really a bug, or simply because of too deep recursion? Confused

01 Sep 2009, 18:30

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8356
Location: Kraków, Poland

Tomasz Grysztar 01 Sep 2009, 18:34

It is a bug, because fasm should display "out of stack space" error in all cases.

01 Sep 2009, 18:34

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