From: Kristen Carlson Accardi <kristen@linux.intel.com>
To: Miroslav Benes <mbenes@suse.cz>
Cc: keescook@chromium.org, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, arjan@linux.intel.com, x86@kernel.org,
linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com, rick.p.edgecombe@intel.com,
live-patching@vger.kernel.org
Subject: Re: [PATCH v5 00/10] Function Granular KASLR
Date: Mon, 28 Sep 2020 10:31:12 -0700 [thread overview]
Message-ID: <5d9b4b306b9cc9109286e2d8f7213be3296d6aa8.camel@linux.intel.com> (raw)
In-Reply-To: <alpine.LSU.2.21.2009251450260.13615@pobox.suse.cz>
Hi,
On Fri, 2020-09-25 at 15:06 +0200, Miroslav Benes wrote:
> Hi Kristen,
>
> On Wed, 23 Sep 2020, Kristen Carlson Accardi wrote:
>
> > Function Granular Kernel Address Space Layout Randomization
> > (fgkaslr)
> > -----------------------------------------------------------------
> > ----
> >
> > This patch set is an implementation of finer grained kernel address
> > space
> > randomization. It rearranges your kernel code at load time
> > on a per-function level granularity, with only around a second
> > added to
> > boot time.
>
> I ran live patching kernel selftests on the patch set and everything
> passed fine.
>
> However, we also use not-yet-upstream set of tests at SUSE for
> testing
> live patching [1] and one of them, klp_tc_12.sh, is failing. You
> should be
> able to run the set on upstream as is.
>
> The test uninterruptedly sleeps in a kretprobed function called by a
> patched one. The current master without fgkaslr patch set reports
> the
> stack of the sleeping task as unreliable and live patching fails.
> The
> situation is different with fgkaslr (even with nofgkaslr on the
> command
> line). The stack is returned as reliable. It looks something like
>
> [<0>] __schedule+0x465/0xa40
> [<0>] schedule+0x55/0xd0
> [<0>] orig_do_sleep+0xb1/0x110 [klp_test_support_mod]
> [<0>] swap_pages+0x7f/0x7f
>
> where the last entry is not reliable. I've seen
> kretprobe_trampoline+0x0/0x4a and some other symbols there too. Since
> the
> patched function (orig_sleep_uninterruptible_set) is not on the
> stack,
> live patching succeeds, which is not intended.
>
> With kprobe setting removed, all works as expected.
>
> So I wonder if there is still some issue with ORC somewhere as you
> mentioned in v4 thread. I'll investigate more next week, but wanted
> to
> report early.
>
> Regards
> Miroslav
>
> [1] https://github.com/lpechacek/qa_test_klp
Thanks for testing and reporting. I will grab your test and see what I
can find.
prev parent reply other threads:[~2020-09-28 17:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200923173905.11219-1-kristen@linux.intel.com>
2020-09-23 17:39 ` [PATCH v5 10/10] livepatch: only match unique symbols when using fgkaslr Kristen Carlson Accardi
2020-09-24 13:06 ` Miroslav Benes
2020-09-25 13:06 ` [PATCH v5 00/10] Function Granular KASLR Miroslav Benes
2020-09-28 17:31 ` Kristen Carlson Accardi [this message]
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=5d9b4b306b9cc9109286e2d8f7213be3296d6aa8.camel@linux.intel.com \
--to=kristen@linux.intel.com \
--cc=arjan@linux.intel.com \
--cc=bp@alien8.de \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-kernel@vger.kernel.org \
--cc=live-patching@vger.kernel.org \
--cc=mbenes@suse.cz \
--cc=mingo@redhat.com \
--cc=rick.p.edgecombe@intel.com \
--cc=tglx@linutronix.de \
--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).