On Thu, Mar 16, 2006 at 08:28:28PM -0800, laura fairhead wrote:
>
>
> Hello,
Hi Laura,
> I just found a bug that affects a number of shells (pressumably the
> code there is from the same roots) in the parser.
>
> The following code;
>
> l='eval "$l"'
> eval "$l"
>
> Which sets off an infinite recursion on 'eval', should result in an
> infinite loop to be terminated by INT (doesnt' work) or at least
> end gracefully with an error "bash: out of memory". Instead the
> system has to kill the shell process because of SEGV fault.
[...]
It's the same with
f() { f; }; f
actually.
~$ bash -c 'f() { f; }; f'
zsh: segmentation fault bash -c 'f() { f; }; f'
(139)~$ zsh -c 'f() { f; }; f'
zsh: segmentation fault zsh -c 'f() { f; }; f'
(139)~$ ksh -c 'f() { f; }; f'
zsh: segmentation fault ksh -c 'f() { f; }; f'
(139)~$ ash -c 'f() { f; }; f'
zsh: segmentation fault ash -c 'f() { f; }; f'
(139)~$ gawk 'function f() { f() } BEGIN { f() }'
zsh: segmentation fault awk 'function f() { f() } BEGIN { f() }'
(139)~$ perl -le 'sub f { f(); }; f'
zsh: killed perl -le 'sub f { f(); }; f'
(137)~$
For perl, it was probably the OOM killer, my Xserver was killed as well.
TCL:
~$ expect -c 'proc f {} { f }; f' 2>&1 | tail
"f "
(procedure "f" line 1)
invoked from within
"f "
(procedure "f" line 1)
invoked from within
"f "
(procedure "f" line 1)
invoked from within
"f"
The recursion limit seems to be 1000, there.
Same for:
expect -c 'set f {eval $f}; eval $f'
Same thing in python (limit 1000 as well) and ruby (limit seems higher).
~$ perl -le '$f = "eval \$f"; eval $f'
is still running but is slowly grabbing all the memory.
--
Stéphane
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