lkml.org 
[lkml]   [2024]   [May]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: CVE-2024-26821: fs: relax mount_setattr() permission checks
On Tue, May 14, 2024 at 02:49:39PM +0200, Anthony Iliopoulos wrote:
> On Wed, Apr 17, 2024 at 11:44:04AM +0200, Greg Kroah-Hartman wrote:
> > Description
> > ===========
> >
> > In the Linux kernel, the following vulnerability has been resolved:
> >
> > fs: relax mount_setattr() permission checks
> >
> > When we added mount_setattr() I added additional checks compared to the
> > legacy do_reconfigure_mnt() and do_change_type() helpers used by regular
> > mount(2). If that mount had a parent then verify that the caller and the
> > mount namespace the mount is attached to match and if not make sure that
> > it's an anonymous mount.
> >
> > The real rootfs falls into neither category. It is neither an anoymous
> > mount because it is obviously attached to the initial mount namespace
> > but it also obviously doesn't have a parent mount. So that means legacy
> > mount(2) allows changing mount properties on the real rootfs but
> > mount_setattr(2) blocks this. I never thought much about this but of
> > course someone on this planet of earth changes properties on the real
> > rootfs as can be seen in [1].
> >
> > Since util-linux finally switched to the new mount api in 2.39 not so
> > long ago it also relies on mount_setattr() and that surfaced this issue
> > when Fedora 39 finally switched to it. Fix this.
> >
> > The Linux kernel CVE team has assigned CVE-2024-26821 to this issue.
>
> This one probably needs to be disputed as it isn't an actual
> vulnerability, but rather a fix for the mount_setattr which previously
> didn't allow reconfiguring the real rootfs similar to what the mount
> syscall always allowed to do.
>
> So it merely brings mount_attr up to par with mount in terms of allowing
> the real rootfs to be reconfigured.
>
> Christian, what do you think ?

Yeah, it's not security related at all. It just allows _additional_
functionality. Not sure how that ended up on the CVE list. Thanks for
pinging about this!

\
 
 \ /
  Last update: 2024-05-15 18:59    [W:0.031 / U:0.208 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site