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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: hch@infradead.org, akpm@linux-foundation.org, tytso@mit.edu,
	viro@zeniv.linux.org.uk, darrick.wong@oracle.com
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH v2 0/2] vfs: make active swap files unwritable
Date: Fri, 28 Jun 2019 11:35:11 -0700
Message-ID: <156174691124.1557844.14293659081769020256.stgit@magnolia> (raw)

Hi all,

I discovered that it's possible for userspace to write to active swap
files and swap devices.  While activated, the kernel effectively holds
an irrevocable (except by swapoff) longterm lease on the storage
associated with the swap device, so we need to shut down this vector for
memory corruption of userspace programs.

If you're going to start using this mess, you probably ought to just
pull from my git trees, which are linked below.

This has been lightly tested with fstests.  Enjoy!
Comments and questions are, as always, welcome.

--D

kernel git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=immutable-swapfiles

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=immutable-swapfiles

             reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-28 18:35 Darrick J. Wong [this message]
2019-06-28 18:35 ` [PATCH 1/2] mm: set S_SWAPFILE on blockdev swap devices Darrick J. Wong
2019-06-28 18:35 ` [PATCH 2/2] vfs: don't allow writes to swap files Darrick J. Wong

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