From: Ingo Molnar <mingo@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>,
Alex Shi <alex.shi@intel.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Will Drewry <wad@chromium.org>, Julien Tinnes <jln@google.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Dan Rosenberg <drosenberg@vsecurity.com>,
"x86@kernel.org" <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Borislav Petkov <borislav.petkov@amd.com>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [kernel-hardening] Re: [PATCH] x86: make IDT read-only
Date: Wed, 10 Apr 2013 11:41:35 +0200 [thread overview]
Message-ID: <20130410094135.GD24443@gmail.com> (raw)
In-Reply-To: <CAGXu5jJNG4o+_-kk=A2AfSRwyQE0pgaQh7YpSjnD_fB-s7U+wA@mail.gmail.com>
* Kees Cook <keescook@chromium.org> wrote:
> > That's the area in which we just map 1:1 to memory. Anything allocated with
> > e.g. kmalloc() ends up with those addresses.
>
> Ah-ha! Yes, I see now when comparing the debug/kernel_page_tables reports. It's
> just the High Kernel Mapping that we care about. Addresses outside that range
> are less of a leak. Excellent, then GDT may not be a problem. Whew.
It's still an infoleak to worry about: any function pointers nearby matter, and
the x86 GDT is obviously full of useful and highly privilege-relevant function
pointers ...
I have no objections against read-only mapping the GDT as well.
Thanks,
Ingo
next prev parent reply other threads:[~2013-04-10 9:41 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-08 22:43 [PATCH] x86: make IDT read-only Kees Cook
2013-04-08 22:47 ` H. Peter Anvin
2013-04-08 22:55 ` Kees Cook
2013-04-08 22:48 ` H. Peter Anvin
2013-04-09 9:23 ` Thomas Gleixner
2013-04-09 9:45 ` Eric W. Biederman
2013-04-10 9:57 ` Ingo Molnar
2013-04-10 10:40 ` Eric W. Biederman
2013-04-10 16:31 ` Eric Northup
2013-04-10 16:48 ` H. Peter Anvin
[not found] ` <alpine.LFD.2.02.1304091122490.21884@ionos>
2013-04-09 18:22 ` [kernel-hardening] " Kees Cook
2013-04-09 18:26 ` H. Peter Anvin
2013-04-09 18:31 ` Kees Cook
2013-04-09 18:39 ` H. Peter Anvin
2013-04-09 18:46 ` Kees Cook
2013-04-09 18:50 ` H. Peter Anvin
2013-04-09 18:53 ` Kees Cook
2013-04-09 18:54 ` Eric Northup
2013-04-09 18:59 ` H. Peter Anvin
2013-04-10 0:43 ` Readonly GDT H. Peter Anvin
2013-04-10 0:53 ` Steven Rostedt
2013-04-10 0:58 ` H. Peter Anvin
2013-04-10 9:42 ` [Xen-devel] " Jan Beulich
2013-04-10 14:16 ` H. Peter Anvin
2013-04-10 18:28 ` H. Peter Anvin
2013-04-10 9:41 ` Ingo Molnar [this message]
2013-04-10 0:03 ` [kernel-hardening] Re: [PATCH] x86: make IDT read-only H. Peter Anvin
2013-04-10 9:52 ` Ingo Molnar
2013-04-08 22:56 ` Maciej W. Rozycki
[not found] ` <alpine.LFD.2.03.1304082350540.25182@linux-mips.org>
2013-04-08 23:00 ` Kees Cook
2013-04-08 23:05 ` Kees Cook
2013-04-08 23:42 ` Maciej W. Rozycki
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=20130410094135.GD24443@gmail.com \
--to=mingo@kernel.org \
--cc=alex.shi@intel.com \
--cc=alexander.h.duyck@intel.com \
--cc=borislav.petkov@amd.com \
--cc=drosenberg@vsecurity.com \
--cc=fweisbec@gmail.com \
--cc=hpa@zytor.com \
--cc=jeremy@goop.org \
--cc=jln@google.com \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=konrad.wilk@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=rostedt@goodmis.org \
--cc=virtualization@lists.linux-foundation.org \
--cc=wad@chromium.org \
--cc=x86@kernel.org \
--cc=xen-devel@lists.xensource.com \
/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).