RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 906639 - libvirt should clean and revert env after fail to create snapshot with a bad img using --reuse-external
Summary: libvirt should clean and revert env after fail to create snapshot with a bad ...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: libvirt
Version: 6.4
Hardware: x86_64
OS: Linux
medium
medium
Target Milestone: rc
: ---
Assignee: Peter Krempa
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2013-02-01 05:24 UTC by Huang Wenlong
Modified: 2014-10-14 04:15 UTC (History)
7 users (show)

Fixed In Version: libvirt-0.10.2-32.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2014-10-14 04:15:09 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2014:1374 0 normal SHIPPED_LIVE libvirt bug fix and enhancement update 2014-10-14 08:11:54 UTC

Description Huang Wenlong 2013-02-01 05:24:33 UTC 
Description of problem:
libvirt should clean and revert env after fail to create snapshot with a
bad img useing --reuse-external
virsh fail should clean and revert env and guest should not be effected

Version-Release number of selected component (if applicable):
libvirt-0.10.2-18.el6.x86_64
qemu-kvm-rhev-0.12.1.2-2.355.el6.x86_64


How reproducible:
100%

Steps to Reproduce:
1.prepare a running guest
# virsh list
Id Name State
----------------------------------------------------
8 bug running


2.touch a empty(bad)img for snapshot create
#touch /var/lib/libvirt/images/bug.bad

# ll /tmp/bad
ls: cannot access /tmp/bad: No such file or directory

3.create a snapshot --with reuse-external even add atomic
#virsh snapshot-create-as bug bad --memspec /tmp/bad --reuse-external
--atomic
error: internal error unable to execute QEMU command 'transaction':
Could not open '/var/lib/libvirt/images/bug.bad': Invalid argument
#echo $?
1

4.check env bad file still there , bug.img's context is cleaned , it
will make selinux AVC denied and guest image turn to read-only
# ll /tmp/bad
-rw-------. 1 root root 307951050 Jan 31 15:10 /tmp/bad

]# ll -Z
-rw-r--r--. qemu qemu unconfined_u:object_r:svirt_image_t:s0:c101,c640
bug.bad
-rw-------. root root system_u:object_r:virt_image_t:s0 bug.img


type=AVC msg=audit(1359615628.274:81086): avc: denied { write } for
pid=25034 comm="qemu-kvm" path="/var/lib/libvirt/images/bug.img"
dev=sda1 ino=7920 scontext=unconfined_u:system_r:svirt_t:s0:c367,c445
tcontext=system_u:object_r:virt_image_t:s0 tclass=file


Actual results:
as steps

Expected results:
virsh fail should clean and revert env and guest should not be effected

Additional info:

--
Comment 1 Peter Krempa 2013-02-04 14:39:06 UTC 
The memory image file is deleted on failure since:

commit a912977a657ae92724c04e8c4e6f70c6e8231849
Author: Peter Krempa <pkrempa>
Date:   Tue Dec 11 12:02:16 2012 +0100

    qemu: snapshot: Remove memory image if external checkpoint fails
    
    When the disk snapshot part of an external system checkpoint fails the
    memory image is retained. This patch adds code to remove the image in
    such case.

v1.0.0-292-ga912977

as of the AVC/selinux issues, those are probably still present.
Comment 2 Peter Krempa 2013-05-31 14:06:39 UTC 
The issue with damaging permissions of the original image is now fixed with:
commit 177046753fa427609f217c319dba6fa465a4add4
Author: Peter Krempa <pkrempa>
Date:   Fri May 31 15:38:46 2013 +0200

    qemu: snapshot: Don't kill access to disk if snapshot creation fails
    
    If snapshot creation failed for example due to invalid use of the
    "REUSE_EXTERNAL" flag, libvirt killed access to the original image file
    instead of the new image file. On machines with selinux this kills the
    whole VM as the selinux context is enforced immediately.
    
    * qemu_driver.c:qemuDomainSnapshotUndoSingleDiskActive():
        - Kill access to the new image file instead of the old one.

v1.0.6-rc2-7-g1770467
Comment 3 Jiri Denemark 2013-06-11 10:05:48 UTC 
We decided not to rebase libvirt in RHEL 6.5 to avoid stability issues
we faced in 6.4. This bug has already been trivially fixed upstream but
it is not considered important enough to be backported to RHEL 6.5.

Thus I'm pushing this bug to RHEL 6.6 (and setting Upstream keyword to
indicate we have patches upstream) for now. If you don't agree with
this resolution, please, give us reasons which you think are strong
enough for us to reevaluate the decision not to backport patches for
this bug.
Comment 9 Shanzhi Yu 2014-04-15 04:02:35 UTC 
verify this bug with libvirt-0.10.2-32.el6.x86_64

Steps:

1. #touch /var/lib/libvirt/images/kvm-rhel6.5-x86_64-qcow2.bad
2. #ll /tmp/bad
ls: cannot access /tmp/bad: No such file or directory
3. #virsh snapshot-create-as rhel6.5 bad  --memspec /tmp/bad  --reuse-external --atomic
error: internal error unable to execute QEMU command 'transaction': Could not open '/var/lib/libvirt/images/kvm-rhel6.5-x86_64-qcow2.bad': Invalid argument
4. ll /tmp/bad
ls: cannot access /tmp/bad: No such file or directory
Comment 11 errata-xmlrpc 2014-10-14 04:15:09 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2014-1374.html
Note You need to log in before you can comment on or make changes to this bug.