Re: os.tmpname security risk?

[Steve Litt <slitt@...>]

On Saturday, July 02, 2011 06:29:52 AM HyperHacker wrote:
> The 5.1 manual states, for os.tmpname():
> > On some systems (POSIX), this function also creates a file with
> > that name, to avoid security risks. (Someone else might create
> > the file with wrong permissions in the time between getting the
> > name and creating the file.)
> 
> But what stops someone from removing that file and creating their
> own, or changing its permissions? It doesn't seem like this really
> mitigates the risk at all.

I think the assumption is you'll use the file very quickly and then 
erase it, making it very hard for someone to switch out the file during 
the short time you'll be using it.

I rolled my own temp file maker that in my opinion is better than those 
offered by Lua's distribution:

http://www.troubleshooters.com/codecorn/lua/luaos.htm#_Temporary_Files

Be careful -- I think the "%%%" in the error message should be "@@@".

Good luck.

SteveT


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Steve Litt
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