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authorMax Reitz <mreitz@redhat.com>2021-03-31 14:28:15 +0200
committerKevin Wolf <kwolf@redhat.com>2021-04-09 18:00:29 +0200
commitf940b0ac6fa67deb9d0b671cf83070f0286c67e1 (patch)
tree7e4851a7f38a63d9e9581c645483d36940fc28cd /tests/qemu-iotests
parent030262a6e4f48b4566778a51d14eb471b2fd2b84 (diff)
iotests: Test mirror-top filter permissions
Add a test accompanying commit 53431b9086b2832ca1aeff0c55e186e9ed79bd11 ("block/mirror: Fix mirror_top's permissions"). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210331122815.51491-1-mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'tests/qemu-iotests')
-rwxr-xr-xtests/qemu-iotests/tests/mirror-top-perms121
-rw-r--r--tests/qemu-iotests/tests/mirror-top-perms.out5
2 files changed, 126 insertions, 0 deletions
diff --git a/tests/qemu-iotests/tests/mirror-top-perms b/tests/qemu-iotests/tests/mirror-top-perms
new file mode 100755
index 0000000000..451a0666f8
--- /dev/null
+++ b/tests/qemu-iotests/tests/mirror-top-perms
@@ -0,0 +1,121 @@
+#!/usr/bin/env python3
+# group: rw
+#
+# Test permissions taken by the mirror-top filter
+#
+# Copyright (C) 2021 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import iotests
+from iotests import qemu_img
+
+# Import qemu after iotests.py has amended sys.path
+# pylint: disable=wrong-import-order
+import qemu
+
+
+image_size = 1 * 1024 * 1024
+source = os.path.join(iotests.test_dir, 'source.img')
+
+
+class TestMirrorTopPerms(iotests.QMPTestCase):
+ def setUp(self):
+ assert qemu_img('create', '-f', iotests.imgfmt, source,
+ str(image_size)) == 0
+ self.vm = iotests.VM()
+ self.vm.add_drive(source)
+ self.vm.add_blockdev(f'null-co,node-name=null,size={image_size}')
+ self.vm.launch()
+
+ # Will be created by the test function itself
+ self.vm_b = None
+
+ def tearDown(self):
+ try:
+ self.vm.shutdown()
+ except qemu.machine.AbnormalShutdown:
+ pass
+
+ if self.vm_b is not None:
+ self.vm_b.shutdown()
+
+ os.remove(source)
+
+ def test_cancel(self):
+ """
+ Before commit 53431b9086b28, mirror-top used to not take any
+ permissions but WRITE and share all permissions. Because it
+ is inserted between the source's original parents and the
+ source, there generally was no parent that would have taken or
+ unshared any permissions on the source, which means that an
+ external process could access the image unhindered by locks.
+ (Unless there was a parent above the protocol node that would
+ take its own locks, e.g. a format driver.)
+ This is bad enough, but if the mirror job is then cancelled,
+ the mirroring VM tries to take back the image, restores the
+ original permissions taken and unshared, and assumes this must
+ just work. But it will not, and so the VM aborts.
+
+ Commit 53431b9086b28 made mirror keep the original permissions
+ and so no other process can "steal" the image.
+
+ (Note that you cannot really do the same with the target image
+ and then completing the job, because the mirror job always
+ took/unshared the correct permissions on the target. For
+ example, it does not share READ_CONSISTENT, which makes it
+ difficult to let some other qemu process open the image.)
+ """
+
+ result = self.vm.qmp('blockdev-mirror',
+ job_id='mirror',
+ device='drive0',
+ target='null',
+ sync='full')
+ self.assert_qmp(result, 'return', {})
+
+ self.vm.event_wait('BLOCK_JOB_READY')
+
+ # We want this to fail because the image cannot be locked.
+ # If it does not fail, continue still and see what happens.
+ self.vm_b = iotests.VM(path_suffix='b')
+ # Must use -blockdev -device so we can use share-rw.
+ # (And we need share-rw=on because mirror-top was always
+ # forced to take the WRITE permission so it can write to the
+ # source image.)
+ self.vm_b.add_blockdev(f'file,node-name=drive0,filename={source}')
+ self.vm_b.add_device('virtio-blk,drive=drive0,share-rw=on')
+ try:
+ self.vm_b.launch()
+ print('ERROR: VM B launched successfully, this should not have '
+ 'happened')
+ except qemu.qmp.QMPConnectError:
+ assert 'Is another process using the image' in self.vm_b.get_log()
+
+ result = self.vm.qmp('block-job-cancel',
+ device='mirror')
+ self.assert_qmp(result, 'return', {})
+
+ self.vm.event_wait('BLOCK_JOB_COMPLETED')
+
+
+if __name__ == '__main__':
+ # No metadata format driver supported, because they would for
+ # example always unshare the WRITE permission. The raw driver
+ # just passes through the permissions from the guest device, and
+ # those are the permissions that we want to test.
+ iotests.main(supported_fmts=['raw'],
+ supported_protocols=['file'])
diff --git a/tests/qemu-iotests/tests/mirror-top-perms.out b/tests/qemu-iotests/tests/mirror-top-perms.out
new file mode 100644
index 0000000000..ae1213e6f8
--- /dev/null
+++ b/tests/qemu-iotests/tests/mirror-top-perms.out
@@ -0,0 +1,5 @@
+.
+----------------------------------------------------------------------
+Ran 1 tests
+
+OK