[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date: Fri, 4 Nov 2011 21:04:06 +0400
From: Solar Designer <solar@...nwall.com>
To: oss-security@...ts.openwall.com
Cc: cve-assign@...re.org
Subject: Re: CVE Request -- kernel: sysctl: restrict write access to dmesg_restrict
Hi Steve,
On Thu, Oct 27, 2011 at 11:38:47PM -0400, Steven M. Christey wrote:
> So, I'll repeat my subtle request in January for someone to try and define
> what the acceptable security boundaries are at this stage, and then it
> should make it easier to interpret what needs a CVE (or not). It sounds
> like this could have some benefits beyond CVE. Looks like Brad Spengler's
> blog post at http://forums.grsecurity.net/viewtopic.php?f=7&t=2522 is a
> great start; based on my (limited) understanding, this suggests that
> CAP_SYS_ADMIN can legitimately transition to full root.
What's "full root"? Full root in the current container or full root on
the host system?
Without container-based virtualization, CAP_SYS_ADMIN is pretty much
equivalent to full root (and I wouldn't ask what that is).
With containers, CAP_SYS_ADMIN inside a container is not supposed to be
equivalent to full root on the host. Such privilege escalation
possibilities are CVE-worthy. However, LXC with procfs mounted is
currently an exception. We can instead have a CVE id for this exception
(not for dmesg_restrict specifically), if desired/appropriate.
With OpenVZ, it is OK to have procfs mounted in a container and not
have a CAP_SYS_ADMIN in container (or other container root access
equivalent) to host root privilege escalation vulnerability (or rather,
such vulnerabilities when found would deserve CVEs of their own).
Since such container-based virtualization for Linux exists where
CAP_SYS_ADMIN is not meant to be equivalent to host root, we should not
disregard CAP_SYS_ADMIN to root privilege escalation bugs in Linux in
general. Many of these are CVE-worthy. However, there are occasional
exceptions, such as this case with LXC and procfs where individual
bypasses are not CVE-worthy (but this entire exception might be
CVE-worthy on its own).
I hope this helps.
Alexander
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.
