From b66ff2c29817f5efa18f5120fd6f089fbf59a933 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Mon, 6 Jul 2020 15:39:52 -0500 Subject: iotests: Specify explicit backing format where sensible There are many existing qcow2 images that specify a backing file but no format. This has been the source of CVEs in the past, but has become more prominent of a problem now that libvirt has switched to -blockdev. With older -drive, at least the probing was always done by qemu (so the only risk of a changed format between successive boots of a guest was if qemu was upgraded and probed differently). But with newer -blockdev, libvirt must specify a format; if libvirt guesses raw where the image was formatted, this results in data corruption visible to the guest; conversely, if libvirt guesses qcow2 where qemu was using raw, this can result in potential security holes, so modern libvirt instead refuses to use images without explicit backing format. The change in libvirt to reject images without explicit backing format has pointed out that a number of tools have been far too reliant on probing in the past. It's time to set a better example in our own iotests of properly setting this parameter. iotest calls to create, rebase, and convert are all impacted to some degree. It's a bit annoying that we are inconsistent on command line - while all of those accept -o backing_file=...,backing_fmt=..., the shortcuts are different: create and rebase have -b and -F, while convert has -B but no -F. (amend has no shortcuts, but the previous patch just deprecated the use of amend to change backing chains). Signed-off-by: Eric Blake Message-Id: <20200706203954.341758-9-eblake@redhat.com> Signed-off-by: Kevin Wolf --- tests/qemu-iotests/270.out | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tests/qemu-iotests/270.out') diff --git a/tests/qemu-iotests/270.out b/tests/qemu-iotests/270.out index c7be111..6dc3b23 100644 --- a/tests/qemu-iotests/270.out +++ b/tests/qemu-iotests/270.out @@ -2,7 +2,7 @@ QA output created by 270 Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=4294967296 wrote 512/512 bytes at offset 0 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) -Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294967296 backing_file=TEST_DIR/t.IMGFMT.base data_file=TEST_DIR/t.IMGFMT.orig +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294967296 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT data_file=TEST_DIR/t.IMGFMT.orig wrote 2147483136/2147483136 bytes at offset 768 2 GiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) No errors were found on the image. -- cgit v1.1