Re: [PATCH v1.1 1/2] generic: test suid/sgid behavior with reflink and dedupe

Darrick J. Wong
2022-03-10T17:48:55Z

On Thu, Feb 17, 2022 at 09:26:15PM -0800, Darrick J. Wong wrote:
> On Wed, Feb 16, 2022 at 03:09:20PM +0000, Filipe Manana wrote:
> > On Thu, Jan 27, 2022 at 9:01 AM Darrick J. Wong <djwong@kernel.org> wrote:
> > >
> > > From: Darrick J. Wong <djwong@kernel.org>
> > >
> > > Make sure that we drop the setuid and setgid bits any time reflink or
> > > dedupe change the file contents.
> > >
> > > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > > ---
> > > v2: drop the congruent oplen checks, that was a mismerge
> > > ---
> > > tests/generic/950 | 107 +++++++++++++++++++++++++++++++++++++++++++++
> > > tests/generic/950.out | 49 +++++++++++++++++++++
> > > tests/generic/951 | 117 +++++++++++++++++++++++++++++++++++++++++++++++++
> > > tests/generic/951.out | 49 +++++++++++++++++++++
> > > tests/generic/952 | 70 +++++++++++++++++++++++++++++
> > > tests/generic/952.out | 13 +++++
> > > 6 files changed, 405 insertions(+)
> > > create mode 100755 tests/generic/950
> > > create mode 100644 tests/generic/950.out
> > > create mode 100755 tests/generic/951
> > > create mode 100644 tests/generic/951.out
> > > create mode 100755 tests/generic/952
> > > create mode 100644 tests/generic/952.out
> > >
> > > diff --git a/tests/generic/950 b/tests/generic/950
> > > new file mode 100755
> > > index 00000000..a7398cb5
> > > --- /dev/null
> > > +++ b/tests/generic/950
> > > @@ -0,0 +1,107 @@
> > > +#! /bin/bash
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +# Copyright (c) 2022 Oracle. All Rights Reserved.
> > > +#
> > > +# FS QA Test 950
> > > +#
> > > +# Functional test for dropping suid and sgid bits as part of a reflink.
> > > +#
> > > +. ./common/preamble
> > > +_begin_fstest auto clone quick
> > > +
> > > +# Import common functions.
> > > +. ./common/filter
> > > +. ./common/reflink
> > > +
> > > +# real QA test starts here
> > > +
> > > +# Modify as appropriate.
> > > +_supported_fs generic
> > > +_require_user
> > > +_require_scratch_reflink
> > > +
> > > +_scratch_mkfs >> $seqres.full
> > > +_scratch_mount
> > > +chmod a+rw $SCRATCH_MNT/
> > > +
> > > +setup_testfile() {
> > > + rm -f $SCRATCH_MNT/a $SCRATCH_MNT/b
> > > + _pwrite_byte 0x58 0 1m $SCRATCH_MNT/a >> $seqres.full
> > > + _pwrite_byte 0x57 0 1m $SCRATCH_MNT/b >> $seqres.full
> > > + chmod a+r $SCRATCH_MNT/b
> > > + sync
> > > +}
> > > +
> > > +commit_and_check() {
> > > + local user="$1"
> > > +
> > > + md5sum $SCRATCH_MNT/a | _filter_scratch
> > > + stat -c '%a %A %n' $SCRATCH_MNT/a | _filter_scratch
> > > +
> > > + local cmd="$XFS_IO_PROG -c 'reflink $SCRATCH_MNT/b 0 0 1m' $SCRATCH_MNT/a"
> > > + if [ -n "$user" ]; then
> > > + su - "$user" -c "$cmd" >> $seqres.full
> > > + else
> > > + $SHELL -c "$cmd" >> $seqres.full
> > > + fi
> > > +
> > > + _scratch_cycle_mount
> > > + md5sum $SCRATCH_MNT/a | _filter_scratch
> > > + stat -c '%a %A %n' $SCRATCH_MNT/a | _filter_scratch
> > > +
> > > + # Blank line in output
> > > + echo
> > > +}
> > > +
> >
> > Hi Darrick,
> >
> > > +# Commit to a non-exec file by an unprivileged user clears suid but leaves
> > > +# sgid.
> > > +echo "Test 1 - qa_user, non-exec file"
> > > +setup_testfile
> > > +chmod a+rws $SCRATCH_MNT/a
> > > +commit_and_check "$qa_user"
> >
> > So this test fails on btrfs, and after taking a look at it, I'm not
> > sure if this expected result is xfs specific or not.
>
> It's.... complicated. g+s without g+x is some holdover from System V
> mandatory file locks, wherein:
>
> "Note that the group-id bit is usually automatically cleared by the
> kernel when a setgid file is written to. This is a security measure. The
> kernel has been modified to recognize the special case of a mandatory
> lock candidate and to refrain from clearing this bit. Similarly the
> kernel has been modified not to run mandatory lock candidates with
> setgid privileges."
>
> https://www.kernel.org/doc/html/v5.14/filesystems/mandatory-locking.html#marking-a-file-for-mandatory-locking
>
> Which, I think, is why XFS preserves the setgid bit. Of course, with
> mandatory locking now deprecated, it's perhaps time to get rid of that
> behavior?
>
> The funny part is, XFS itself doesn't make this decision;
> should_remove_suid in the VFS does:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/inode.c?h=v5.17-rc4#n1967
>
> So XFS has this behavior because generic_remap_file_range_prep calls
> file_modified -> file_remove_privs -> dentry_needs_remove_privs ->
> should_remove_suid...
>
> > On btrfs we get sgid cleared:
> >
> > 310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > 6666 -rwSrwSrw- SCRATCH_MNT/a
> > 3784de23efab7a2074c9ec66901e39e5 SCRATCH_MNT/a
> > -2666 -rw-rwSrw- SCRATCH_MNT/a
> > +666 -rw-rw-rw- SCRATCH_MNT/a
> >
> > This happens because at btrfs_setattr() we use setattr_copy() to
> > change the inode's ->i_mode.
> > I see that xfs does not use it, instead it manipulates ->i_mode
> > directly with xfs_setattr_mode().
> >
> > At setattr_copy() we get the sgid removed:
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/attr.c?h=v5.17-rc4#n241
>
> ...OH, now I get it. notify_change() sees that ATTR_KILL_SUID is set,
> and sets ATTR_MODE. If you use setattr_copy, will always clear the
> setgid bit. XFS doesn't (as you point out) which is why the behavior is
> different. xfs_setattr_nonsize looks like it open-codes a lot of what
> setattr_copy does, but without the gid-killing quirk.
>
> I'm not sure what to do here -- the VFS code is clearly conflicted about
> this. Given that the weird behavior only exists to support a dying
> feature, we might as well just make everyone clear sgid.
>
> Digging around in xfs_setattr_nonsize a bit more, I suspect the reason
> why we handle ATTR_[UG]ID separately is because of the xfs quota
> subsystem, but I don't see any reason why xfs couldn't adopt
> setattr_copy for the rest of the ATTR_* bits.

For anyone still following this thread: I ported XFS to setattr_copy and
will send a patch to Eryu fixing generic/673:

https://lore.kernel.org/linux-xfs/8aa8a6d8-109e-99dd-d904-268df6058447@virtuozzo.com/T/#t

Apparently XFS has simply been out of date since 7fa294c8991c ("userns:
Allow chown and setgid preservation")

--D

> Sorry about injecting a new fail test at you all. :/
>
> > Testing this with buffered writes instead of reflink, to see how xfs,
> > btrfs and ext4 behave:
> >
> > #!/bin/bash
> >
> > DEV=/dev/sdj
> > MNT=/mnt/sdj
> > XFS_IO=/home/fdmanana/xfsprogs/sbin/xfs_io
> >
> > mkfs.btrfs -f $DEV >/dev/null
> > #mkfs.ext4 -F $DEV >/dev/null
> > #mkfs.xfs -f $DEV >/dev/null
> > mount $DEV $MNT
> >
> > $XFS_IO -f -c "pwrite -S 0xab 0 128K" $MNT/foo >/dev/null
> > chmod a+rws $MNT/foo
> >
> > echo "Inode mode before: $(stat -c '%a %A %n' $MNT/foo)"
> >
> > cmd="$XFS_IO -c 'pwrite -S 0xcd 64K 4K' $MNT/foo"
> > su - fsgqa -c "$cmd" >/dev/null
> >
> > echo "Inode mode after: $(stat -c '%a %A %n' $MNT/foo)"
> >
> > umount $DEV
> >
> > btrfs and ext4 give the same result, as both use the setattr_copy()
> > from generic code, where sgid gets removed:
> >
> > Inode mode before: 6666 -rwSrwSrw- /mnt/sdj/foo
> > Inode mode after: 666 -rw-rw-rw- /mnt/sdj/foo
> >
> > xfs gives the same behaviour as this test expects for reflinks, sgid
> > is preserved:
> >
> > Inode mode before: 6666 -rwSrwSrw- /mnt/sdj/foo
> > Inode mode after: 2666 -rw-rwSrw- /mnt/sdj/foo
> >
> > So I wonder if this is a behaviour that can be fs specific, if xfs is
> > behaving incorrectly, or the generic code, setattr_copy(), is not
> > correct.
> > Any thoughts?
>
> "Ow, my brain hurts." and "I wonder if Dave has better context about
> this"...
>
> --D
>
> >
> > Thanks.
> >
> >
> >
> >
> >
> > > +
> > > +# Commit to a group-exec file by an unprivileged user clears suid and sgid.
> > > +echo "Test 2 - qa_user, group-exec file"
> > > +setup_testfile
> > > +chmod g+x,a+rws $SCRATCH_MNT/a
> > > +commit_and_check "$qa_user"
> > > +
> > > +# Commit to a user-exec file by an unprivileged user clears suid but not sgid.
> > > +echo "Test 3 - qa_user, user-exec file"
> > > +setup_testfile
> > > +chmod u+x,a+rws,g-x $SCRATCH_MNT/a
> > > +commit_and_check "$qa_user"
> > > +
> > > +# Commit to a all-exec file by an unprivileged user clears suid and sgid.
> > > +echo "Test 4 - qa_user, all-exec file"
> > > +setup_testfile
> > > +chmod a+rwxs $SCRATCH_MNT/a
> > > +commit_and_check "$qa_user"
> > > +
> > > +# Commit to a non-exec file by root clears suid but leaves sgid.
> > > +echo "Test 5 - root, non-exec file"
> > > +setup_testfile
> > > +chmod a+rws $SCRATCH_MNT/a
> > > +commit_and_check
> > > +
> > > +# Commit to a group-exec file by root clears suid and sgid.
> > > +echo "Test 6 - root, group-exec file"
> > > +setup_testfile
> > > +chmod g+x,a+rws $SCRATCH_MNT/a
> > > +commit_and_check
> > > +
> > > +# Commit to a user-exec file by root clears suid but not sgid.
> > > +echo "Test 7 - root, user-exec file"
> > > +setup_testfile
> > > +chmod u+x,a+rws,g-x $SCRATCH_MNT/a
> > > +commit_and_check
> > > +
> > > +# Commit to a all-exec file by root clears suid and sgid.
> > > +echo "Test 8 - root, all-exec file"
> > > +setup_testfile
> > > +chmod a+rwxs $SCRATCH_MNT/a
> > > +commit_and_check
> > > +
> > > +# success, all done
> > > +status=0
> > > +exit
> > > diff --git a/tests/generic/950.out b/tests/generic/950.out
> > > new file mode 100644
> > > index 00000000..b42e4931
> > > --- /dev/null
> > > +++ b/tests/generic/950.out
> > > @@ -0,0 +1,49 @@
> > > +QA output created by 950
> > > +Test 1 - qa_user, non-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6666 -rwSrwSrw- SCRATCH_MNT/a
> > > +3784de23efab7a2074c9ec66901e39e5 SCRATCH_MNT/a
> > > +2666 -rw-rwSrw- SCRATCH_MNT/a
> > > +
> > > +Test 2 - qa_user, group-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6676 -rwSrwsrw- SCRATCH_MNT/a
> > > +3784de23efab7a2074c9ec66901e39e5 SCRATCH_MNT/a
> > > +676 -rw-rwxrw- SCRATCH_MNT/a
> > > +
> > > +Test 3 - qa_user, user-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6766 -rwsrwSrw- SCRATCH_MNT/a
> > > +3784de23efab7a2074c9ec66901e39e5 SCRATCH_MNT/a
> > > +2766 -rwxrwSrw- SCRATCH_MNT/a
> > > +
> > > +Test 4 - qa_user, all-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6777 -rwsrwsrwx SCRATCH_MNT/a
> > > +3784de23efab7a2074c9ec66901e39e5 SCRATCH_MNT/a
> > > +777 -rwxrwxrwx SCRATCH_MNT/a
> > > +
> > > +Test 5 - root, non-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6666 -rwSrwSrw- SCRATCH_MNT/a
> > > +3784de23efab7a2074c9ec66901e39e5 SCRATCH_MNT/a
> > > +6666 -rwSrwSrw- SCRATCH_MNT/a
> > > +
> > > +Test 6 - root, group-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6676 -rwSrwsrw- SCRATCH_MNT/a
> > > +3784de23efab7a2074c9ec66901e39e5 SCRATCH_MNT/a
> > > +6676 -rwSrwsrw- SCRATCH_MNT/a
> > > +
> > > +Test 7 - root, user-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6766 -rwsrwSrw- SCRATCH_MNT/a
> > > +3784de23efab7a2074c9ec66901e39e5 SCRATCH_MNT/a
> > > +6766 -rwsrwSrw- SCRATCH_MNT/a
> > > +
> > > +Test 8 - root, all-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6777 -rwsrwsrwx SCRATCH_MNT/a
> > > +3784de23efab7a2074c9ec66901e39e5 SCRATCH_MNT/a
> > > +6777 -rwsrwsrwx SCRATCH_MNT/a
> > > +
> > > diff --git a/tests/generic/951 b/tests/generic/951
> > > new file mode 100755
> > > index 00000000..8484f225
> > > --- /dev/null
> > > +++ b/tests/generic/951
> > > @@ -0,0 +1,117 @@
> > > +#! /bin/bash
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +# Copyright (c) 2022 Oracle. All Rights Reserved.
> > > +#
> > > +# FS QA Test 951
> > > +#
> > > +# Functional test for dropping suid and sgid bits as part of a deduplication.
> > > +#
> > > +. ./common/preamble
> > > +_begin_fstest auto clone quick
> > > +
> > > +# Import common functions.
> > > +. ./common/filter
> > > +. ./common/reflink
> > > +
> > > +# real QA test starts here
> > > +
> > > +# Modify as appropriate.
> > > +_supported_fs generic
> > > +_require_user
> > > +_require_scratch_reflink
> > > +_require_xfs_io_command dedupe
> > > +
> > > +_scratch_mkfs >> $seqres.full
> > > +_scratch_mount
> > > +chmod a+rw $SCRATCH_MNT/
> > > +
> > > +setup_testfile() {
> > > + rm -f $SCRATCH_MNT/a $SCRATCH_MNT/b
> > > + _pwrite_byte 0x58 0 1m $SCRATCH_MNT/a >> $seqres.full
> > > + _pwrite_byte 0x58 0 1m $SCRATCH_MNT/b >> $seqres.full
> > > + chmod a+r $SCRATCH_MNT/b
> > > + sync
> > > +}
> > > +
> > > +commit_and_check() {
> > > + local user="$1"
> > > +
> > > + md5sum $SCRATCH_MNT/a | _filter_scratch
> > > + stat -c '%a %A %n' $SCRATCH_MNT/a | _filter_scratch
> > > +
> > > + local before_freesp=$(_get_available_space $SCRATCH_MNT)
> > > +
> > > + local cmd="$XFS_IO_PROG -c 'dedupe $SCRATCH_MNT/b 0 0 1m' $SCRATCH_MNT/a"
> > > + if [ -n "$user" ]; then
> > > + su - "$user" -c "$cmd" >> $seqres.full
> > > + else
> > > + $SHELL -c "$cmd" >> $seqres.full
> > > + fi
> > > +
> > > + _scratch_cycle_mount
> > > + md5sum $SCRATCH_MNT/a | _filter_scratch
> > > + stat -c '%a %A %n' $SCRATCH_MNT/a | _filter_scratch
> > > +
> > > + local after_freesp=$(_get_available_space $SCRATCH_MNT)
> > > +
> > > + echo "before: $before_freesp; after: $after_freesp" >> $seqres.full
> > > + if [ $after_freesp -le $before_freesp ]; then
> > > + echo "expected more free space after dedupe"
> > > + fi
> > > +
> > > + # Blank line in output
> > > + echo
> > > +}
> > > +
> > > +# Commit to a non-exec file by an unprivileged user clears suid but leaves
> > > +# sgid.
> > > +echo "Test 1 - qa_user, non-exec file"
> > > +setup_testfile
> > > +chmod a+rws $SCRATCH_MNT/a
> > > +commit_and_check "$qa_user"
> > > +
> > > +# Commit to a group-exec file by an unprivileged user clears suid and sgid.
> > > +echo "Test 2 - qa_user, group-exec file"
> > > +setup_testfile
> > > +chmod g+x,a+rws $SCRATCH_MNT/a
> > > +commit_and_check "$qa_user"
> > > +
> > > +# Commit to a user-exec file by an unprivileged user clears suid but not sgid.
> > > +echo "Test 3 - qa_user, user-exec file"
> > > +setup_testfile
> > > +chmod u+x,a+rws,g-x $SCRATCH_MNT/a
> > > +commit_and_check "$qa_user"
> > > +
> > > +# Commit to a all-exec file by an unprivileged user clears suid and sgid.
> > > +echo "Test 4 - qa_user, all-exec file"
> > > +setup_testfile
> > > +chmod a+rwxs $SCRATCH_MNT/a
> > > +commit_and_check "$qa_user"
> > > +
> > > +# Commit to a non-exec file by root clears suid but leaves sgid.
> > > +echo "Test 5 - root, non-exec file"
> > > +setup_testfile
> > > +chmod a+rws $SCRATCH_MNT/a
> > > +commit_and_check
> > > +
> > > +# Commit to a group-exec file by root clears suid and sgid.
> > > +echo "Test 6 - root, group-exec file"
> > > +setup_testfile
> > > +chmod g+x,a+rws $SCRATCH_MNT/a
> > > +commit_and_check
> > > +
> > > +# Commit to a user-exec file by root clears suid but not sgid.
> > > +echo "Test 7 - root, user-exec file"
> > > +setup_testfile
> > > +chmod u+x,a+rws,g-x $SCRATCH_MNT/a
> > > +commit_and_check
> > > +
> > > +# Commit to a all-exec file by root clears suid and sgid.
> > > +echo "Test 8 - root, all-exec file"
> > > +setup_testfile
> > > +chmod a+rwxs $SCRATCH_MNT/a
> > > +commit_and_check
> > > +
> > > +# success, all done
> > > +status=0
> > > +exit
> > > diff --git a/tests/generic/951.out b/tests/generic/951.out
> > > new file mode 100644
> > > index 00000000..f7099ea2
> > > --- /dev/null
> > > +++ b/tests/generic/951.out
> > > @@ -0,0 +1,49 @@
> > > +QA output created by 951
> > > +Test 1 - qa_user, non-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6666 -rwSrwSrw- SCRATCH_MNT/a
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6666 -rwSrwSrw- SCRATCH_MNT/a
> > > +
> > > +Test 2 - qa_user, group-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6676 -rwSrwsrw- SCRATCH_MNT/a
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6676 -rwSrwsrw- SCRATCH_MNT/a
> > > +
> > > +Test 3 - qa_user, user-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6766 -rwsrwSrw- SCRATCH_MNT/a
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6766 -rwsrwSrw- SCRATCH_MNT/a
> > > +
> > > +Test 4 - qa_user, all-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6777 -rwsrwsrwx SCRATCH_MNT/a
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6777 -rwsrwsrwx SCRATCH_MNT/a
> > > +
> > > +Test 5 - root, non-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6666 -rwSrwSrw- SCRATCH_MNT/a
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6666 -rwSrwSrw- SCRATCH_MNT/a
> > > +
> > > +Test 6 - root, group-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6676 -rwSrwsrw- SCRATCH_MNT/a
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6676 -rwSrwsrw- SCRATCH_MNT/a
> > > +
> > > +Test 7 - root, user-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6766 -rwsrwSrw- SCRATCH_MNT/a
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6766 -rwsrwSrw- SCRATCH_MNT/a
> > > +
> > > +Test 8 - root, all-exec file
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6777 -rwsrwsrwx SCRATCH_MNT/a
> > > +310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
> > > +6777 -rwsrwsrwx SCRATCH_MNT/a
> > > +
> > > diff --git a/tests/generic/952 b/tests/generic/952
> > > new file mode 100755
> > > index 00000000..86443dcc
> > > --- /dev/null
> > > +++ b/tests/generic/952
> > > @@ -0,0 +1,70 @@
> > > +#! /bin/bash
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +# Copyright (c) 2022 Oracle. All Rights Reserved.
> > > +#
> > > +# FS QA Test 952
> > > +#
> > > +# Functional test for dropping suid and sgid capabilities as part of a reflink.
> > > +#
> > > +. ./common/preamble
> > > +_begin_fstest auto clone quick
> > > +
> > > +# Import common functions.
> > > +. ./common/filter
> > > +. ./common/reflink
> > > +
> > > +# real QA test starts here
> > > +
> > > +# Modify as appropriate.
> > > +_supported_fs generic
> > > +_require_user
> > > +_require_command "$GETCAP_PROG" getcap
> > > +_require_command "$SETCAP_PROG" setcap
> > > +_require_scratch_reflink
> > > +
> > > +_scratch_mkfs >> $seqres.full
> > > +_scratch_mount
> > > +chmod a+rw $SCRATCH_MNT/
> > > +
> > > +setup_testfile() {
> > > + rm -f $SCRATCH_MNT/a $SCRATCH_MNT/b
> > > + _pwrite_byte 0x58 0 1m $SCRATCH_MNT/a >> $seqres.full
> > > + _pwrite_byte 0x57 0 1m $SCRATCH_MNT/b >> $seqres.full
> > > + chmod a+rwx $SCRATCH_MNT/a $SCRATCH_MNT/b
> > > + $SETCAP_PROG cap_setgid,cap_setuid+ep $SCRATCH_MNT/a
> > > + sync
> > > +}
> > > +
> > > +commit_and_check() {
> > > + local user="$1"
> > > +
> > > + stat -c '%a %A %n' $SCRATCH_MNT/a | _filter_scratch
> > > + _getcap -v $SCRATCH_MNT/a | _filter_scratch
> > > +
> > > + local cmd="$XFS_IO_PROG -c 'reflink $SCRATCH_MNT/b 0 0 1m' $SCRATCH_MNT/a"
> > > + if [ -n "$user" ]; then
> > > + su - "$user" -c "$cmd" >> $seqres.full
> > > + else
> > > + $SHELL -c "$cmd" >> $seqres.full
> > > + fi
> > > +
> > > + stat -c '%a %A %n' $SCRATCH_MNT/a | _filter_scratch
> > > + _getcap -v $SCRATCH_MNT/a | _filter_scratch
> > > +
> > > + # Blank line in output
> > > + echo
> > > +}
> > > +
> > > +# Commit by an unprivileged user clears capability bits.
> > > +echo "Test 1 - qa_user"
> > > +setup_testfile
> > > +commit_and_check "$qa_user"
> > > +
> > > +# Commit by root leaves capability bits.
> > > +echo "Test 2 - root"
> > > +setup_testfile
> > > +commit_and_check
> > > +
> > > +# success, all done
> > > +status=0
> > > +exit
> > > diff --git a/tests/generic/952.out b/tests/generic/952.out
> > > new file mode 100644
> > > index 00000000..eac9e76a
> > > --- /dev/null
> > > +++ b/tests/generic/952.out
> > > @@ -0,0 +1,13 @@
> > > +QA output created by 952
> > > +Test 1 - qa_user
> > > +777 -rwxrwxrwx SCRATCH_MNT/a
> > > +SCRATCH_MNT/a cap_setgid,cap_setuid=ep
> > > +777 -rwxrwxrwx SCRATCH_MNT/a
> > > +SCRATCH_MNT/a
> > > +
> > > +Test 2 - root
> > > +777 -rwxrwxrwx SCRATCH_MNT/a
> > > +SCRATCH_MNT/a cap_setgid,cap_setuid=ep
> > > +777 -rwxrwxrwx SCRATCH_MNT/a
> > > +SCRATCH_MNT/a
> > > +