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From: Daniel Colascione <dancol@google.com>
To: Jonathan Corbet <corbet@lwn.net>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Iurii Zaikin <yzaikin@google.com>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Mel Gorman <mgorman@techsingularity.net>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Peter Xu <peterx@redhat.com>,
	Daniel Colascione <dancol@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Jerome Glisse <jglisse@redhat.com>, Shaohua Li <shli@fb.com>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, timmurray@google.com,
	minchan@google.com, sspatil@google.com, lokeshgidra@google.com
Subject: [PATCH 0/2] Control over userfaultfd kernel-fault handling
Date: Wed, 22 Apr 2020 17:26:30 -0700
Message-ID: <20200423002632.224776-1-dancol@google.com> (raw)

This small patch series adds a new flag to userfaultfd(2) that allows
callers to give up the ability to handle user-mode faults with the
resulting UFFD file object. In then add a new sysctl to require
unprivileged callers to use this new flag.

The purpose of this new interface is to decrease the change of an
unprivileged userfaultfd user taking advantage of userfaultfd to
enhance security vulnerabilities by lengthening the race window in
kernel code.

This patch series is split from [1].

[1] https://lore.kernel.org/lkml/20200211225547.235083-1-dancol@google.com/

Daniel Colascione (2):
  Add UFFD_USER_MODE_ONLY
  Add a new sysctl knob: unprivileged_userfaultfd_user_mode_only

 Documentation/admin-guide/sysctl/vm.rst | 13 +++++++++++++
 fs/userfaultfd.c                        | 18 ++++++++++++++++--
 include/linux/userfaultfd_k.h           |  1 +
 include/uapi/linux/userfaultfd.h        |  9 +++++++++
 kernel/sysctl.c                         |  9 +++++++++
 5 files changed, 48 insertions(+), 2 deletions(-)

-- 
2.26.2.303.gf8c07b1a785-goog


             reply index

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-23  0:26 Daniel Colascione [this message]
2020-04-23  0:26 ` [PATCH 1/2] Add UFFD_USER_MODE_ONLY Daniel Colascione
2020-07-24 14:28   ` Michael S. Tsirkin
2020-07-24 14:46     ` Lokesh Gidra
2020-07-26 10:09       ` Michael S. Tsirkin
2020-04-23  0:26 ` [PATCH 2/2] Add a new sysctl knob: unprivileged_userfaultfd_user_mode_only Daniel Colascione
2020-05-06 19:38   ` Peter Xu
2020-05-07 19:15     ` Jonathan Corbet
2020-05-20  4:06       ` Andrea Arcangeli
2020-05-08 16:52   ` Michael S. Tsirkin
2020-05-08 16:54     ` Michael S. Tsirkin
2020-05-20  4:59       ` Andrea Arcangeli
2020-05-20 18:03         ` Kees Cook
2020-05-20 19:48           ` Andrea Arcangeli
2020-05-20 19:51             ` Andrea Arcangeli
2020-05-20 20:17               ` Lokesh Gidra
2020-05-20 21:16                 ` Andrea Arcangeli
2020-07-17 12:57                   ` Jeffrey Vander Stoep
2020-07-23 17:30                     ` Lokesh Gidra
2020-07-24  0:13                       ` Nick Kralevich
2020-07-24 13:40                         ` Michael S. Tsirkin
2020-08-06  0:43                           ` Nick Kralevich
2020-08-06  5:44                             ` Michael S. Tsirkin
2020-08-17 22:11                               ` Lokesh Gidra
2020-09-04  3:34                                 ` Andrea Arcangeli
2020-09-05  0:36                                   ` Lokesh Gidra
2020-07-24 14:01 ` [PATCH 0/2] Control over userfaultfd kernel-fault handling Michael S. Tsirkin
2020-07-24 14:41   ` Lokesh Gidra

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