[Devel] vzctl: race condition at open("/sbin/init")

[Vasily Kulikov]

On Tue, Sep 18, 2012 at 19:09 +0400, Kir Kolyshkin wrote:
> On 07/25/2012 11:07 PM, Vasily Kulikov wrote:
> >Hi,
> >
> >stat()+open() is not atomic in the code below, so there is a race
> >condition.  A container root may change /sbin/init between these calls
> >to e.g. FIFO and then make the vzctl's process hang up on read().
> >
> >I'd add O_NOCTTY to open's flags and change stat() before open() to
> >fstat() just after open().
> 
> Thanks a lot for reporting!
> 
> Does this patch seems sufficient to you?
> http://git.openvz.org/?p=vzctl;a=commitdiff;h=7c47a7953

Yes, look good.

Thanks!

-- 
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments