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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: david@fromorbit.com, darrick.wong@oracle.com
Cc: sandeen@redhat.com, linux-nfs@vger.kernel.org,
	linux-cifs@vger.kernel.org, linux-unionfs@vger.kernel.org,
	linux-xfs@vger.kernel.org, linux-mm@kvack.org,
	linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	ocfs2-devel@oss.oracle.com
Subject: [PATCH v6 00/28] fs: fixes for serious clone/dedupe problems
Date: Sun, 21 Oct 2018 09:15:03 -0700	[thread overview]
Message-ID: <154013850285.29026.16168387526580596209.stgit@magnolia> (raw)

Hi all,

Dave, Eric, and I have been chasing a stale data exposure bug in the XFS
reflink implementation, and tracked it down to reflink forgetting to do
some of the file-extending activities that must happen for regular
writes.

We then started auditing the clone, dedupe, and copyfile code and
realized that from a file contents perspective, clonerange isn't any
different from a regular file write.  Unfortunately, we also noticed
that *unlike* a regular write, clonerange skips a ton of overflow
checks, such as validating the ranges against s_maxbytes, MAX_NON_LFS,
and RLIMIT_FSIZE.  We also observed that cloning into a file did not
strip security privileges (suid, capabilities) like a regular write
would.  I also noticed that xfs and ocfs2 need to dump the page cache
before remapping blocks, not after.

In fixing the range checking problems I also realized that both dedupe
and copyfile tell userspace how much of the requested operation was
acted upon.  Since the range validation can shorten a clone request (or
we can ENOSPC midway through), we might as well plumb the short
operation reporting back through the VFS indirection code to userspace.
I added a few more cleanups to the xfs code per reviewer suggestions.

So, here's the whole giant pile of patches[1] that fix all the problems.
This branch is against current upstream (4.19-rc8).  The patch
"generic: test reflink side effects" recently sent to fstests exercises
the fixes in this series.  Tests are in [2].

--D

[1] https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=djwong-devel
[2] https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfstests-dev.git/log/?h=djwong-devel

             reply	other threads:[~2018-10-21 16:15 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-21 16:15 Darrick J. Wong [this message]
2018-10-21 16:15 ` [PATCH 01/28] vfs: vfs_clone_file_prep_inodes should return EINVAL for a clone from beyond EOF Darrick J. Wong
2018-10-21 16:15 ` [PATCH 02/28] vfs: check file ranges before cloning files Darrick J. Wong
2018-10-21 16:15 ` [PATCH 03/28] vfs: exit early from zero length remap operations Darrick J. Wong
2018-10-21 16:15 ` [PATCH 04/28] vfs: strengthen checking of file range inputs to generic_remap_checks Darrick J. Wong
2018-10-21 16:15 ` [PATCH 05/28] vfs: avoid problematic remapping requests into partial EOF block Darrick J. Wong
2018-10-21 16:15 ` [PATCH 06/28] vfs: skip zero-length dedupe requests Darrick J. Wong
2018-10-21 16:15 ` [PATCH 07/28] vfs: rename vfs_clone_file_prep to be more descriptive Darrick J. Wong
2018-10-21 16:15 ` [PATCH 08/28] vfs: rename clone_verify_area to remap_verify_area Darrick J. Wong
2018-10-21 16:16 ` [PATCH 09/28] vfs: combine the clone and dedupe into a single remap_file_range Darrick J. Wong
2018-10-21 16:16 ` [PATCH 10/28] vfs: pass remap flags to generic_remap_file_range_prep Darrick J. Wong
2018-10-21 16:16 ` [PATCH 11/28] vfs: pass remap flags to generic_remap_checks Darrick J. Wong
2018-10-21 16:16 ` [PATCH 12/28] vfs: remap helper should update destination inode metadata Darrick J. Wong
2018-10-21 16:16 ` [PATCH 13/28] vfs: make remap_file_range functions take and return bytes completed Darrick J. Wong
2018-10-21 16:16 ` [PATCH 14/28] vfs: plumb remap flags through the vfs clone functions Darrick J. Wong
2018-10-21 16:16 ` [PATCH 15/28] vfs: plumb remap flags through the vfs dedupe functions Darrick J. Wong
2018-10-21 16:16 ` [PATCH 16/28] vfs: enable remap callers that can handle short operations Darrick J. Wong
2018-10-21 16:17 ` [PATCH 17/28] vfs: hide file range comparison function Darrick J. Wong
2018-10-21 16:17 ` [PATCH 18/28] vfs: clean up generic_remap_file_range_prep return value Darrick J. Wong
2018-10-21 16:17 ` [PATCH 19/28] ocfs2: truncate page cache for clone destination file before remapping Darrick J. Wong
2018-10-21 16:17 ` [PATCH 20/28] ocfs2: fix pagecache truncation prior to reflink Darrick J. Wong
2018-10-21 16:17 ` [PATCH 21/28] ocfs2: support partial clone range and dedupe range Darrick J. Wong
2018-10-21 16:17 ` [PATCH 22/28] ocfs2: remove ocfs2_reflink_remap_range Darrick J. Wong
2018-10-21 16:17 ` [PATCH 23/28] xfs: fix pagecache truncation prior to reflink Darrick J. Wong
2018-10-21 16:17 ` [PATCH 24/28] xfs: clean up xfs_reflink_remap_blocks call site Darrick J. Wong
2018-10-22  2:11   ` Dave Chinner
2018-10-21 16:17 ` [PATCH 25/28] xfs: support returning partial reflink results Darrick J. Wong
2018-10-22  2:14   ` Dave Chinner
2018-10-21 16:18 ` [PATCH 26/28] xfs: remove redundant remap partial EOF block checks Darrick J. Wong
2018-10-21 16:18 ` [PATCH 27/28] xfs: remove xfs_reflink_remap_range Darrick J. Wong
2018-10-22  2:17   ` Dave Chinner
2018-10-21 16:18 ` [PATCH 28/28] xfs: remove [cm]time update from reflink calls Darrick J. Wong
2018-10-22  2:18   ` Dave Chinner
2018-10-22  2:21 ` [PATCH v6 00/28] fs: fixes for serious clone/dedupe problems Dave Chinner
2018-10-22  4:37   ` Dave Chinner
2018-10-22  4:52     ` Al Viro
2018-10-22  5:08       ` Dave Chinner
2018-10-22  5:42         ` Amir Goldstein
2018-10-22  6:55           ` Dave Chinner

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