Re: Why side-effects on open(2) are evil. (was Re: [RFD w/info-PATCH] device arguments from lookup)

Alexander Viro
2001-05-19T14:59:16Z

On Sat, 19 May 2001 Andries.Brouwer@cwi.nl wrote:

> > A lot of stuff relies on the fact that close(open(foo, O_RDONLY))
> > is a no-op. Breaking that assumption is a Bad Thing(tm).
>
> Also here I would like to agree. Unfortunately this is false.
> Opening device files often has interesting side effects.

Too bad. They can be triggered by similar races between attacker
changing the type of object (file<->symlink) and backup.