Date: Tue Nov  1 18:25:43 2005
From: ben at decadentplace.org.uk (Ben Hutchings)
Subject: readdir_r considered harmful

3APA3A wrote:
> Dear Ben Hutchings,
> 
> 
> If  someone  uses pathconf to determine buffer size it's his own problem
> and  he creates vulnerability by himself. You can list such applications
> as vulnerable to race conditions.
<snip>
> NAME_MAX  is  defined  in limits.h and should be 255 according to latest
> POSIX extension. I see no problem with POSIX standard in this case.
> 
> See:
> http://www.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html
<snip>

If you had read the above page more carefully, you would have seen these
paragraphs:

"The values in the following list may be constants within an
implementation or may vary from one pathname to another. For example,
file systems or directories may have different characteristics.

"A definition of one of the values shall be omitted from the <limits.h>
header on specific implementations where the corresponding value is
equal to or greater than the stated minimum, but where the value can
vary depending on the file to which it is applied. The actual value
supported for a specific pathname shall be provided by the pathconf()
function."

-- 
Ben Hutchings
When you say `I wrote a program that crashed Windows', people just stare ...
and say `Hey, I got those with the system, *for free*'. - Linus Torvalds
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