Re: O_NOLINK for open()

[Andreas Schwab]

Brent Casavant <bcasavan@xxxxxxx> writes:

> I could mmap a temporary tmpfs file (tmpfs so that if there is a
> machine crash no sensitive data persists) which is created with
> permissions of 0, immediately unlink it, and pass the file
> descriptor through an AF_UNIX socket.  This does open up a very
> small window of vulnerability if another process is able to chmod
> the file and open it before the unlink.

Only the owner can chmod a file, so why is that a vulnerability?

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@xxxxxxx
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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