Re: os.tmpname security risk?

[Patrick Donnelly <batrick@...>]

On Wed, Jul 13, 2011 at 8:25 PM, HyperHacker <hyperhacker@gmail.com> wrote:
> True, you usually open the file immediately after creating it, but
> that leads to the potential security risk/race condition mentioned in
> the first post (and the reason os.tmpname() creates the file for you)
> - there is still a small window of opportunity (which an attacker
> might have various ways of enlarging) to sneak in and tamper with the
> file between the time you create it and the time you open it. (Or
> another app creates the same file, overwriting yours during that
> window - unlikely, but possible.)

You appear confused. There is no "small window of opportunity" between
when the file is made and when you open it. In fact, the file is
created when it is opened (O_CREAT|O_EXCL). There is no opportunity
with those flags for someone to "sneak" in a fake version of the file.

-- 
- Patrick Donnelly