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Message #84345
[Bug 1890501] Re: [OSSA-2020-006] Soft reboot after live-migration reverts instance to original source domain XML (CVE-2020-17376)
** Changed in: nova/pike
Status: Fix Committed => Fix Released
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https://bugs.launchpad.net/bugs/1890501
Title:
[OSSA-2020-006] Soft reboot after live-migration reverts instance to
original source domain XML (CVE-2020-17376)
Status in OpenStack Compute (nova):
Fix Released
Status in OpenStack Compute (nova) pike series:
Fix Released
Status in OpenStack Compute (nova) queens series:
Fix Released
Status in OpenStack Compute (nova) rocky series:
Fix Released
Status in OpenStack Compute (nova) stein series:
Fix Released
Status in OpenStack Compute (nova) train series:
Fix Released
Status in OpenStack Compute (nova) ussuri series:
Fix Released
Status in OpenStack Compute (nova) victoria series:
Fix Released
Status in OpenStack Security Advisory:
Fix Released
Bug description:
Description
===========
When live migrating instances with attached volumes Nova will first
ensure that the volumes are connected on the destination before
updating the underlying domain XML to be used on the destination to
correctly map to these volumes.
At present in the case of volumes connected over iSCSI or FC this
ensures that the instance points to the correct host block devices as
these may differ from the source.
However if a user requests a soft reboot of an instance after a successful live migration the underlying libvirt domain will rollback to the XML definition used on the source. In the case of volumes provided over iSCSI or FC etc this can potentially lead to the wrong
volume being attached to the instance on the destination leading to possible data exfiltration or corruption.
It appears that this is due to Nova not providing
VIR_MIGRATE_PARAM_PERSIST_XML during the migration resulting in the
original source domains persistent configuration being used instead:
/**
* VIR_MIGRATE_PARAM_DEST_XML:
*
* virDomainMigrate* params field: the new configuration to be used for the
* domain on the destination host as VIR_TYPED_PARAM_STRING. The configuration
* must include an identical set of virtual devices, to ensure a stable guest
* ABI across migration. Only parameters related to host side configuration
* can be changed in the XML. Hypervisors which support this field will forbid
* migration if the provided XML would cause a change in the guest ABI. This
* field cannot be used to rename the domain during migration (use
* VIR_MIGRATE_PARAM_DEST_NAME field for that purpose). Domain name in the
* destination XML must match the original domain name.
*
* Omitting this parameter keeps the original domain configuration. Using this
* field with hypervisors that do not support changing domain configuration
* during migration will result in a failure.
*/
# define VIR_MIGRATE_PARAM_DEST_XML "destination_xml"
/**
* VIR_MIGRATE_PARAM_PERSIST_XML:
*
* virDomainMigrate* params field: the new persistent configuration to be used
* for the domain on the destination host as VIR_TYPED_PARAM_STRING.
* This field cannot be used to rename the domain during migration (use
* VIR_MIGRATE_PARAM_DEST_NAME field for that purpose). Domain name in the
* destination XML must match the original domain name.
*
* Omitting this parameter keeps the original domain persistent configuration.
* Using this field with hypervisors that do not support changing domain
* configuration during migration will result in a failure.
*/
# define VIR_MIGRATE_PARAM_PERSIST_XML "persistent_xml"
Steps to reproduce
==================
0) Deploy overcloud with multipath and iscsi/LVM cinder backend.
1) Delete all instances and check no device path remained on both host1 and host2.
2) Boot instances, VM1 on host1 and VM2 on host2.
$ cinder create --name cirros1 --volume-type lvm --image cirros 1
$ cinder create --name cirros2 --volume-type lvm --image cirros 1
$ nova boot --block-device-mapping vda=$cirrosvol1 ... --host host1.localdomain testvm1
$ nova boot --block-device-mapping vda=$cirrosvol2 ... --host host2.localdomain testvm2
$ openstack server add floating ip testvm1 xx.xx.xx.xx
$ openstack server add floating ip testvm2 yy.yy.yy.yy
3) Soft reboot each instances and check no problem has occured.
$ nova reboot testvm1
$ nova reboot testvm2
4) Execute live-migration VM1 to host2, check VMs for the device path setting in
each XML.
$ nova live-migration testvm1 host2.localdomain
5) Execute soft reboot VM1, check VMs for the device path setting in each XML.
$ nova reboot testvm1
6) Login to each VMs and check syslogs.
Expected result
===============
After live-migration and soft reboot instance, device paths indicated
by virsh dumpxml --inactive and qemu XML file are changed to new value
fit to destination host.
Actual result
=============
After live-migration and soft reboot instance, device paths indicated
by virsh dumpxml --inactive and qemu XML file are the value of source
host before migration.
Environment
===========
1. Exact version of OpenStack you are running. See the following
list for all releases: http://docs.openstack.org/releases/
Reported downstream against stable/train and libvirt 5.6.0-10.
2. Which hypervisor did you use?
(For example: Libvirt + KVM, Libvirt + XEN, Hyper-V, PowerKVM, ...)
What's the version of that?
libvirt + KVM
2. Which storage type did you use?
(For example: Ceph, LVM, GPFS, ...)
What's the version of that?
LVM/iSCSI with multipath enabled but any host block based storage
backend will do.
3. Which networking type did you use?
(For example: nova-network, Neutron with OpenVSwitch, ...)
N/A
Logs & Configs
==============
The following test env logs are copied verbatim from a private
downstream security bug:
https://bugzilla.redhat.com/show_bug.cgi?id=1862353
* Device paths initial state
host1 host2
===================================================================================================
VM1 multipath -ll 360014053825c172898b4ba4a5353515c dm-0 ---
virsh dumpxml <source dev='/dev/dm-0' index='1'/> ---
virsh dumpxml --inactive <source dev='/dev/dm-0'/> ---
qemu xml file <source dev='/dev/dm-0'/> ---
---------------------------------------------------------------------------------------------------
VM2 multipath -ll --- 36001405fc681536d0124af2a9fd99c10 dm-0
virsh dumpxml --- <source dev='/dev/dm-0' index='1'/>
virsh dumpxml --inactive --- <source dev='/dev/dm-0'/>
qemu xml file --- <source dev='/dev/dm-0'/>
* Device paths after VM1 live-migration to host2
host1 host2
===================================================================================================
VM1 multipath -ll --- 360014053825c172898b4ba4a5353515c dm-2
virsh dumpxml --- <source dev='/dev/dm-2' index='1'/>
virsh dumpxml --inactive --- <source dev='/dev/dm-0'/> <== not dm-2
qemu xml file --- <source dev='/dev/dm-0'/> <== not dm-2
---------------------------------------------------------------------------------------------------
VM2 multipath -ll --- 36001405fc681536d0124af2a9fd99c10 dm-0
virsh dumpxml --- <source dev='/dev/dm-0' index='1'/>
virsh dumpxml --inactive --- <source dev='/dev/dm-0'/>
qemu xml file --- <source dev='/dev/dm-0'/>
* Device paths after soft reboot VM1 on host2
host1 host2
===================================================================================================
VM1 multipath -ll --- 360014053825c172898b4ba4a5353515c dm-2
virsh dumpxml --- <source dev='/dev/dm-0' index='1'/> <== changed to dm-0
virsh dumpxml --inactive --- <source dev='/dev/dm-0'/>
qemu xml file --- <source dev='/dev/dm-0'/>
---------------------------------------------------------------------------------------------------
VM2 multipath -ll --- 36001405fc681536d0124af2a9fd99c10 dm-0
virsh dumpxml --- <source dev='/dev/dm-0' index='1'/>
virsh dumpxml --inactive --- <source dev='/dev/dm-0'/>
qemu xml file --- <source dev='/dev/dm-0'/>
* VM1 syslog file before live-migration
$ cat /var/log/messages
...
Jul 28 05:28:38 cirrostestvm1 kern.info kernel: [ 0.780031] usb 1-1: new full-speed USB device number 2 using uhci_hcd
Jul 28 05:28:39 cirrostestvm1 kern.info kernel: [ 1.272305] Refined TSC clocksource calibration: 2099.976 MHz.
Jul 28 05:28:40 cirrostestvm1 authpriv.info dropbear[260]: Running in background
Jul 28 05:28:40 cirrostestvm1 daemon.info init: reloading /etc/inittab
Jul 28 05:28:40 cirrostestvm1 daemon.info init: starting pid 1, tty '/dev/ttyS0': '/sbin/getty -L 115200 ttyS0 vt100 '
Jul 28 05:28:40 cirrostestvm1 daemon.info init: starting pid 1, tty '/dev/tty1': '/sbin/getty 115200 tty1'
Jul 28 05:28:48 cirrostestvm1 kern.debug kernel: [ 10.992106] eth0: no IPv6 routers present
Jul 28 05:29:45 cirrostestvm1 authpriv.info dropbear[301]: Child connection from **.**.**.**:33648
Jul 28 05:29:48 cirrostestvm1 authpriv.notice dropbear[301]: Password auth succeeded for 'cirros' from **.**.**.**:33648
$
* VM1 syslog file after soft reboot on host2
hostname command return correct value, but VM1 syslog is recorded by VM2.
(in some cases, VM1 and VM2 syslog files are destroyed and cannot be read as text file)
$ hostname
cirrostestvm1
$ cat /var/log/messages | tail
Jul 28 06:03:01 cirrostestvm2 authpriv.info dropbear[325]: Child connection from 172.31.151.1:35894
Jul 28 06:03:05 cirrostestvm2 authpriv.notice dropbear[325]: Password auth succeeded for 'cirros' from **.**.**.**:35894
Jul 28 06:03:05 cirrostestvm2 authpriv.info dropbear[325]: Exit (cirros): Disconnect received
Jul 28 06:03:30 cirrostestvm2 authpriv.info dropbear[328]: Child connection from **.**.**.**:36352
Jul 28 06:03:34 cirrostestvm2 authpriv.notice dropbear[328]: Password auth succeeded for 'cirros' from **.**.**.**:36352
Jul 28 06:03:34 cirrostestvm2 authpriv.info dropbear[328]: Exit (cirros): Disconnect received
Jul 28 06:03:39 cirrostestvm2 authpriv.info dropbear[331]: Child connection from **.**.**.**:36484
Jul 28 06:03:41 cirrostestvm2 authpriv.info dropbear[331]: Exit before auth (user 'cirros', 0 fails): Exited normally
Jul 28 06:03:45 cirrostestvm2 authpriv.info dropbear[332]: Child connection from **.**.**.**:36588
Jul 28 06:03:49 cirrostestvm2 authpriv.notice dropbear[332]: Password auth succeeded for 'cirros' from **.**.**.**:36588
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