[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date: Fri, 16 Apr 2021 08:04:50 -0700
From: Steve Beattie <steve.beattie@...onical.com>
To: oss-security@...ts.openwall.com
Subject: Re: [CVE-2021-3493] Ubuntu Linux kernel overlayfs fs
caps privilege escalation
On Fri, Apr 16, 2021 at 04:53:50PM +0200, Salvatore Bonaccorso wrote:
> Hi Steve,
>
> On Thu, Apr 15, 2021 at 02:31:14PM -0700, Steve Beattie wrote:
> > Hello,
> >
> > An independent security researcher reported via the SSD Secure
> > Disclosure program that the overlayfs stacking file system within the
> > Linux kernel as used within Ubuntu did not properly validate the
> > application of file capabilities against user namespaces.
> >
> > This issue is likely Ubuntu specific, as Ubuntu carries a patch to
> > enable unprivileged overlayfs mounts. The combination of that patch
> > plus allowing unprivileged user namespaces by default in Ubuntu allows
> > an unprivileged attacker to gain elevated privileges.
> >
> > A commit that addresses the issue was applied in the upstream kernel:
> >
> > 7c03e2cda4a5 ("vfs: move cap_convert_nscap() call into vfs_setxattr()") (v5.10)
>
> For completeness, this though was in v5.11-rc1 right?
Yes, sorry, thanks for the correction.
--
Steve Beattie
<sbeattie@...ntu.com>
Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
