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From: Mike Rapoport <rppt@linux.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: Andrea Arcangeli <aarcange@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	Daniel Colascione <dancol@google.com>,
	Jann Horn <jannh@google.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Lokesh Gidra <lokeshgidra@google.com>,
	Nick Kralevich <nnk@google.com>, Nosh Minwalla <nosh@google.com>,
	Pavel Emelyanov <ovzxemul@gmail.com>,
	Tim Murray <timmurray@google.com>,
	linux-api@vger.kernel.org, linux-mm@kvack.org,
	Mike Rapoport <rppt@linux.ibm.com>
Subject: [PATCH 0/1] userfaultfd: require CAP_SYS_PTRACE for UFFD_FEATURE_EVENT_FORK
Date: Tue,  5 Nov 2019 17:29:36 +0200	[thread overview]
Message-ID: <1572967777-8812-1-git-send-email-rppt@linux.ibm.com> (raw)

Hi,

A while ago Andy noticed [1] that UFFD_FEATURE_EVENT_FORK used by an
unprivileged user may have security implications.

As the first step of the solution the following patch limits the
availably of UFFD_FEATURE_EVENT_FORK only for those having CAP_SYS_PTRACE.

The usage of CAP_SYS_PTRACE ensures compatibility with CRIU.

Yet, if there are other users of non-cooperative userfaultfd that run
without CAP_SYS_PTRACE, they would be broken :(

[1] https://lore.kernel.org/lkml/CALCETrWY+5ynDct7eU_nDUqx=okQvjm=Y5wJvA4ahBja=CQXGw@mail.gmail.com

Mike Rapoport (1):
  userfaultfd: require CAP_SYS_PTRACE for UFFD_FEATURE_EVENT_FORK

 fs/userfaultfd.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

-- 
2.7.4



             reply	other threads:[~2019-11-05 15:29 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-05 15:29 Mike Rapoport [this message]
2019-11-05 15:29 ` [PATCH 1/1] userfaultfd: require CAP_SYS_PTRACE for UFFD_FEATURE_EVENT_FORK Mike Rapoport
2019-11-05 15:37   ` Andrea Arcangeli
2019-11-05 15:55   ` Daniel Colascione
2019-11-05 16:00     ` Andy Lutomirski
2019-11-05 16:06       ` Daniel Colascione
2019-11-05 16:33         ` Andrea Arcangeli
2019-11-05 16:39           ` Daniel Colascione
2019-11-05 16:55             ` Andrea Arcangeli
2019-11-05 17:02               ` Daniel Colascione
2019-11-05 17:30                 ` Andrea Arcangeli
2019-11-05 22:01                 ` Andy Lutomirski
2019-11-05 22:10                   ` Daniel Colascione
2019-11-05 16:24       ` Andrea Arcangeli
2019-11-05 16:41         ` Daniel Colascione
2019-11-07  8:39           ` Mike Rapoport
2019-11-07  8:54             ` Daniel Colascione
2019-11-07 15:38               ` Andrea Arcangeli
2019-11-07 16:15                 ` Daniel Colascione
2019-11-07 18:22                   ` Andrea Arcangeli
2019-11-07 18:50                     ` Daniel Colascione
2019-11-07 19:27                       ` Andrea Arcangeli
2019-11-10 17:02                     ` Andy Lutomirski
2019-11-05 15:59   ` Aleksa Sarai

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