From: Jiri Kosina <jikos@kernel.org>
To: Jann Horn <jannh@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Greg KH <gregkh@linuxfoundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@suse.com>, Linux-MM <linux-mm@kvack.org>,
kernel list <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged
Date: Sun, 6 Jan 2019 00:09:02 +0100 (CET) [thread overview]
Message-ID: <nycvar.YFH.7.76.1901060001590.16954@cbobk.fhfr.pm> (raw)
In-Reply-To: <CAG48ez2jAp9xkPXQmVXm0PqNrFGscg9BufQRem2UD8FGX-YzPw@mail.gmail.com>
On Sat, 5 Jan 2019, Jann Horn wrote:
> > Provide vm.mincore_privileged sysctl, which makes it possible to mincore()
> > start returning -EPERM in case it's invoked by a process lacking
> > CAP_SYS_ADMIN.
> >
> > The default behavior stays "mincore() can be used by anybody" in order to
> > be conservative with respect to userspace behavior.
> >
> > [1] https://www.theregister.co.uk/2019/01/05/boffins_beat_page_cache/
>
> Just checking: I guess /proc/$pid/pagemap (iow, the pagemap_read()
> handler) is less problematic because it only returns data about the
> state of page tables, and doesn't query the address_space? In other
> words, it permits monitoring evictions, but non-intrusively detecting
> that something has been loaded into memory by another process is
> harder?
So I was just about to immediately reply that we don't expose pagemap
anymore due to rowhammer, but apparently that's not true any more
(this behavioud was originally introduced by ab676b7d6fbf, but then
changed via 1c90308e7a77 (and further adjusted for swap entries in
ab6ecf247a, but I guess that's not all that interesting).
Hmm.
But unless it has been mapped with MAP_POPULATE (whcih is outside the
attacker's control), there is no guarantee that the mappings would
actually be there, right?
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2019-01-05 23:09 UTC|newest]
Thread overview: 161+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-05 17:27 [PATCH] mm/mincore: allow for making sys_mincore() privileged Jiri Kosina
2019-01-05 19:14 ` Vlastimil Babka
2019-01-05 19:24 ` Jiri Kosina
2019-01-05 19:38 ` Vlastimil Babka
2019-01-08 9:14 ` Bernd Petrovitsch
2019-01-08 11:37 ` Jiri Kosina
2019-01-08 13:53 ` Bernd Petrovitsch
2019-01-08 14:08 ` Kirill A. Shutemov
2019-01-05 19:44 ` kbuild test robot
2019-01-05 19:46 ` Linus Torvalds
2019-01-05 20:12 ` Jiri Kosina
2019-01-05 20:17 ` Linus Torvalds
2019-01-05 20:43 ` Jiri Kosina
2019-01-05 21:54 ` Linus Torvalds
2019-01-06 11:33 ` Kevin Easton
2019-01-08 8:50 ` Kevin Easton
2019-01-18 14:23 ` Tejun Heo
2019-01-05 20:13 ` Linus Torvalds
2019-01-05 19:56 ` kbuild test robot
2019-01-05 22:54 ` Jann Horn
2019-01-05 23:05 ` Linus Torvalds
2019-01-05 23:16 ` Linus Torvalds
2019-01-05 23:28 ` Linus Torvalds
2019-01-05 23:39 ` Linus Torvalds
2019-01-06 0:11 ` Matthew Wilcox
2019-01-06 0:22 ` Linus Torvalds
2019-01-06 1:50 ` Linus Torvalds
2019-01-06 21:46 ` Linus Torvalds
2019-01-08 4:43 ` Dave Chinner
2019-01-08 17:57 ` Linus Torvalds
2019-01-09 2:24 ` Dave Chinner
2019-01-09 2:31 ` Jiri Kosina
2019-01-09 4:39 ` Dave Chinner
2019-01-09 10:08 ` Jiri Kosina
2019-01-10 1:15 ` Dave Chinner
2019-01-10 7:54 ` Jiri Kosina
2019-01-09 18:25 ` Linus Torvalds
2019-01-10 0:44 ` Dave Chinner
2019-01-10 1:18 ` Linus Torvalds
2019-01-10 5:26 ` Andy Lutomirski
2019-01-10 14:47 ` Matthew Wilcox
2019-01-10 21:44 ` Dave Chinner
2019-01-10 21:59 ` Linus Torvalds
2019-01-11 1:47 ` Dave Chinner
2019-01-10 7:03 ` Dave Chinner
2019-01-10 11:47 ` Linus Torvalds
2019-01-10 12:24 ` Dominique Martinet
2019-01-10 22:11 ` Linus Torvalds
2019-01-11 2:03 ` Dave Chinner
2019-01-11 2:18 ` Linus Torvalds
2019-01-11 4:04 ` Dave Chinner
2019-01-11 4:08 ` Andy Lutomirski
2019-01-11 7:20 ` Dave Chinner
2019-01-11 7:08 ` Linus Torvalds
2019-01-11 7:36 ` Dave Chinner
2019-01-11 16:26 ` Linus Torvalds
2019-01-15 23:45 ` Dave Chinner
2019-01-16 4:54 ` Linus Torvalds
2019-01-16 5:49 ` Linus Torvalds
2019-01-17 1:26 ` Dave Chinner
2019-02-20 15:49 ` Nicolai Stange
2019-01-11 4:57 ` Dominique Martinet
2019-01-11 7:11 ` Linus Torvalds
2019-01-11 7:32 ` Dominique Martinet
2019-01-16 0:42 ` Josh Snyder
2019-01-16 5:00 ` Linus Torvalds
2019-01-16 5:25 ` Andy Lutomirski
2019-01-16 5:34 ` Linus Torvalds
2019-01-16 5:46 ` Dominique Martinet
2019-01-16 5:58 ` Linus Torvalds
2019-01-16 6:34 ` Dominique Martinet
2019-01-16 7:52 ` Josh Snyder
2019-01-16 12:18 ` Kevin Easton
2019-01-17 21:45 ` Vlastimil Babka
2019-01-18 4:49 ` Linus Torvalds
2019-01-18 18:58 ` Vlastimil Babka
2019-01-16 16:12 ` Jiri Kosina
2019-01-16 17:48 ` Linus Torvalds
2019-01-16 20:23 ` Jiri Kosina
2019-01-16 21:37 ` Matthew Wilcox
2019-01-16 21:41 ` Jiri Kosina
2019-01-17 9:52 ` Cyril Hrubis
2019-01-28 13:49 ` Cyril Hrubis
2019-01-17 4:51 ` Linus Torvalds
2019-01-18 4:54 ` Linus Torvalds
2019-01-17 1:49 ` Dominique Martinet
2019-01-23 20:27 ` Linus Torvalds
2019-01-23 20:35 ` Linus Torvalds
2019-01-23 23:12 ` Jiri Kosina
2019-01-24 0:20 ` Linus Torvalds
2019-01-24 0:24 ` Dominique Martinet
2019-01-24 12:45 ` Dominique Martinet
2019-01-24 14:25 ` Jiri Kosina
2019-01-27 22:35 ` Jiri Kosina
2019-01-28 0:05 ` Dominique Martinet
2019-01-29 23:52 ` Jiri Kosina
2019-01-30 9:09 ` Michal Hocko
2019-01-30 12:29 ` Jiri Kosina
2019-01-16 12:36 ` Matthew Wilcox
2019-01-10 14:50 ` Matthew Wilcox
2019-01-11 7:36 ` Jiri Kosina
2019-01-17 2:22 ` Dave Chinner
2019-01-17 8:18 ` Jiri Kosina
2019-01-17 21:06 ` Dave Chinner
2019-01-07 4:32 ` Dominique Martinet
2019-01-07 10:33 ` Vlastimil Babka
2019-01-07 11:08 ` Dominique Martinet
2019-01-07 11:59 ` Vlastimil Babka
2019-01-07 13:29 ` Daniel Gruss
2019-01-07 10:10 ` Michael Ellerman
2019-01-05 23:09 ` Jiri Kosina [this message]
2019-01-30 12:44 ` [PATCH 0/3] mincore() and IOCB_NOWAIT adjustments Vlastimil Babka
2019-01-30 12:44 ` [PATCH 1/3] mm/mincore: make mincore() more conservative Vlastimil Babka
2019-01-31 9:43 ` Michal Hocko
2019-01-31 9:51 ` Dominique Martinet
2019-01-31 17:46 ` Josh Snyder
2019-02-01 8:56 ` Vlastimil Babka
2019-03-06 23:13 ` Andrew Morton
2019-03-07 0:01 ` Jiri Kosina
2019-03-07 0:40 ` Dominique Martinet
2019-03-07 5:46 ` Jiri Kosina
2019-01-30 12:44 ` [PATCH 2/3] mm/filemap: initiate readahead even if IOCB_NOWAIT is set for the I/O Vlastimil Babka
2019-01-30 15:04 ` Florian Weimer
2019-01-30 15:15 ` Jiri Kosina
2019-01-31 10:47 ` Florian Weimer
2019-01-31 11:34 ` Jiri Kosina
2019-01-31 9:56 ` Michal Hocko
2019-01-31 10:15 ` Jiri Kosina
2019-01-31 10:23 ` Michal Hocko
2019-01-31 10:30 ` Jiri Kosina
2019-01-31 11:32 ` Michal Hocko
2019-01-31 17:54 ` Linus Torvalds
2019-02-01 5:13 ` Dave Chinner
2019-02-01 7:05 ` Linus Torvalds
2019-02-01 7:21 ` Linus Torvalds
2019-02-01 1:44 ` Dave Chinner
2019-02-12 15:48 ` Jiri Kosina
2019-01-31 12:04 ` Daniel Gruss
2019-01-31 12:06 ` Vlastimil Babka
2019-01-31 12:08 ` Jiri Kosina
2019-01-31 12:57 ` Daniel Gruss
2019-01-30 12:44 ` [PATCH 3/3] mm/mincore: provide mapped status when cached status is not allowed Vlastimil Babka
2019-01-31 10:09 ` Michal Hocko
2019-02-01 9:04 ` Vlastimil Babka
2019-02-01 9:11 ` Michal Hocko
2019-02-01 9:27 ` Vlastimil Babka
2019-02-06 20:14 ` Jiri Kosina
2019-02-12 3:44 ` Jiri Kosina
2019-02-12 6:36 ` Michal Hocko
2019-02-12 13:09 ` Jiri Kosina
2019-02-12 14:01 ` Michal Hocko
2019-03-06 12:11 ` [PATCH 0/3] mincore() and IOCB_NOWAIT adjustments Jiri Kosina
2019-03-06 22:35 ` Andrew Morton
2019-03-06 22:48 ` Jiri Kosina
2019-03-06 23:23 ` Andrew Morton
2019-03-06 23:32 ` Dominique Martinet
2019-03-06 23:38 ` Andrew Morton
2019-03-09 16:53 ` Linus Torvalds
2019-03-12 14:17 ` [PATCH v2 0/2] prevent mincore() page cache leaks Vlastimil Babka
2019-03-12 14:17 ` [PATCH v2 1/2] mm/mincore: make mincore() more conservative Vlastimil Babka
2019-03-12 14:17 ` [PATCH v2 2/2] mm/mincore: provide mapped status when cached status is not allowed Vlastimil Babka
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