Re: [Bug-tar] opening files with O_NONBLOCK causes problems

[Kamil Dudka]

On Thursday 05 January 2012 23:30:26 Paul Eggert wrote:
> On 01/04/12 07:20, Vitezslav Cizek wrote:
> > Opening an
> > offline file with O_NONBLOCK and issuing a read(2) tells DMF (HSM
> > software) to initiate recall of the file, but the O_NONBLOCK tells DMF to
> > not block the process
>
> Thanks for reporting the problem.  GNU tar uses O_NONBLOCK for security
> reasons, to avoid problems when attackers substitute special files for
> regular ones just before tar opens them.

Is there a known attack on tar that the use of O_NONBLOCK can prevent?  
Otherwise, there is no excuse to introduce an unspecified behavior IMO.

Kamil