From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Olaf Hering <olaf@aepfle.de>
Cc: Wei Liu <wei.liu2@citrix.com>,
Ian Jackson <Ian.Jackson@eu.citrix.com>,
Ian Campbell <Ian.Campbell@citrix.com>,
Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH for-4.5] tools/pygrub: Fix TOCTOU race introduced by c/s 63dcc68
Date: Wed, 29 Oct 2014 18:09:31 +0000 [thread overview]
Message-ID: <54512D5B.1040003@citrix.com> (raw)
In-Reply-To: <20141029160322.GA22428@aepfle.de>
On 29/10/14 16:03, Olaf Hering wrote:
> On Wed, Oct 29, Andrew Cooper wrote:
>
>> In addition, use os.makedirs() which will also create intermediate directories
>> if they don't exist.
> Can this happen in practice, given that /var/run/xen is created by the
> runlevel scripts already? The mkdir is now really just @XEN_RUN_DIR@/pygrub.
>
> Olaf
Yes, although I presume not given the runlevel scripts.
XenServer, and Xapi in particular, is very different from an upstream xl
based system. It has traditionally had its own initscripts. We are in
the process of disentangling these, but it is not a trivial amount of work.
The result is that I have positively proved that XenServer hit this race
during automatic testing. I agree that it shouldn't happen in reality
for a system configured as expected, but that fact alone doesn't
invalidate the fix itself.
~Andrew
next prev parent reply other threads:[~2014-10-29 18:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-29 14:09 [PATCH for-4.5] tools/pygrub: Fix TOCTOU race introduced by c/s 63dcc68 Andrew Cooper
2014-10-29 16:03 ` Olaf Hering
2014-10-29 18:09 ` Andrew Cooper [this message]
2014-10-29 19:43 ` Olaf Hering
2014-11-04 10:48 ` Ian Campbell
2014-11-04 10:52 ` Please *justify* your use of the for-4.5 tag when posting patches Ian Campbell
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