From: Peter Zijlstra <peterz@infradead.org>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Andi Kleen <andi@firstfloor.org>,
x86@kernel.org, keescook@chromium.org,
linux-kernel@vger.kernel.org, sashal@kernel.org,
Andi Kleen <ak@linux.intel.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v1] x86: Pin cr4 FSGSBASE
Date: Tue, 26 May 2020 09:57:36 +0200 [thread overview]
Message-ID: <20200526075736.GH317569@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200526065618.GC2580410@kroah.com>
On Tue, May 26, 2020 at 08:56:18AM +0200, Greg KH wrote:
> On Mon, May 25, 2020 at 10:28:48PM -0700, Andi Kleen wrote:
> > From: Andi Kleen <ak@linux.intel.com>
> >
> > Since there seem to be kernel modules floating around that set
> > FSGSBASE incorrectly, prevent this in the CR4 pinning. Currently
> > CR4 pinning just checks that bits are set, this also checks
> > that the FSGSBASE bit is not set, and if it is clears it again.
>
> So we are trying to "protect" ourselves from broken out-of-tree kernel
> modules now? Why stop with this type of check, why not just forbid them
> entirely if we don't trust them? :)
Oh, I have a bunch of patches pending for that :-)
It will basically decode the module text and refuse to load the module
for most CPL0 instruction.
next prev parent reply other threads:[~2020-05-26 7:57 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-26 5:28 [PATCH v1] x86: Pin cr4 FSGSBASE Andi Kleen
2020-05-26 6:56 ` Greg KH
2020-05-26 7:57 ` Peter Zijlstra [this message]
2020-05-26 8:17 ` Greg KH
2020-05-26 9:17 ` Peter Zijlstra
2020-05-26 10:16 ` Greg KH
2020-05-26 15:48 ` Andi Kleen
2020-05-26 16:20 ` Kees Cook
2020-05-26 16:32 ` Greg KH
2020-05-26 17:24 ` Wojtek Porczyk
2020-05-27 7:07 ` Greg KH
2020-05-27 10:58 ` Wojtek Porczyk
2020-05-26 16:15 ` Kees Cook
2020-05-26 21:16 ` Greg KH
2020-05-26 16:38 ` Kees Cook
2020-05-26 23:14 ` Andi Kleen
2020-05-27 10:31 ` Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200526075736.GH317569@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=ak@linux.intel.com \
--cc=andi@firstfloor.org \
--cc=gregkh@linuxfoundation.org \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=sashal@kernel.org \
--cc=stable@vger.kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).