[issue1372] zlibmodule.c: int overflow in PyZlib_decompress

[Peter Weseloh]

Peter Weseloh added the comment:

You are right. The format should be 'l'. I overlooked that. In my case the
optional 'buf_size' parameter of 'decompress' is not used anyhow.
Shall I change the patch accordingly?

It work well for me and I now checked the code of PyArg_ParseTuple
(Python/getargs.c) to see what happens. As far as I understand, the given
pointer is casted to a pointer to int if the format is 'i' (line  630) . On
a 64 bit machine this leads to a downcast from a (64 bit) long to a (32 bit)
int, which is OK AFAIK, but I could be wrong.

Thanks for pointing that out,
Peter
2007/11/2, Guido van Rossum <[EMAIL PROTECTED]>:
>
>
> Guido van Rossum added the comment:
>
> I trust that there's a problem, but this can't be right -- the address
> of r_strlen is passed to PyArg_ParseTuple corresponding to an 'i' format
> letter.  That will never do.
>
> ----------
> assignee:  -> nnorwitz
> nosy: +gvanrossum, nnorwitz
>
> __________________________________
> Tracker <[EMAIL PROTECTED]>
> <http://bugs.python.org/issue1372>
> __________________________________
>

Added file: http://bugs.python.org/file8681/unnamed

__________________________________
Tracker <[EMAIL PROTECTED]>
<http://bugs.python.org/issue1372>
__________________________________
You are right. The format should be &#39;l&#39;. I overlooked that. In my case 
the optional &#39;buf_size&#39; parameter of &#39;decompress&#39; is not used 
anyhow.<br>Shall I change the patch accordingly?<br><br>It work well for me and 
I now checked the code of PyArg_ParseTuple (Python/getargs.c) to see what 
happens. As far as I understand, the given pointer is casted to a pointer to 
int if the format is &#39;i&#39; (line&nbsp; 630) . On a 64 bit machine this 
leads to a downcast from a (64 bit) long to a (32 bit) int, which is OK AFAIK, 
but I could be wrong. 
<br><br>Thanks for pointing that out,<br>Peter<br><div><span 
class="gmail_quote">2007/11/2, Guido van Rossum &lt;<a href="mailto:[EMAIL 
PROTECTED]">[EMAIL PROTECTED]</a>&gt;:</span><blockquote class="gmail_quote" 
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; 
padding-left: 1ex;">
<br>Guido van Rossum added the comment:<br><br>I trust that there&#39;s a 
problem, but this can&#39;t be right -- the address<br>of r_strlen is passed to 
PyArg_ParseTuple corresponding to an &#39;i&#39; 
format<br>letter.&nbsp;&nbsp;That will never do.
<br><br>----------<br>assignee:&nbsp;&nbsp;-&gt; nnorwitz<br>nosy: +gvanrossum, 
nnorwitz<br><br>__________________________________<br>Tracker &lt;<a 
href="mailto:[EMAIL PROTECTED]">[EMAIL PROTECTED]</a>&gt;<br>&lt;<a 
href="http://bugs.python.org/issue1372";>
http://bugs.python.org/issue1372</a>&gt;<br>__________________________________<br></blockquote></div><br>


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