qvm-block treats system disks as attachable block devices #1600

andrewdavidwong · Jan 9, 2016

qvm-block and Qubes Manager both treat the disk(s) on which Qubes is installed as attachable block devices:

[user@dom0 ~]$ qvm-block -l
dom0:sda     <name>
dom0:sdb     <name>

In Qubes Manager, these disks are available as options to attach to VMs.

sda and sdb are in a RAID1 configuration, with an encrypted LUKS volume on top, and Qubes installed in that volume.

I have not attempted to attach sda or sdb to any VM, for obvious reasons.

LUKS volumes on secondary internal disks are also treated the same way:

[user@dom0 ~]$ qvm-block -l
dom0:dm-2     luks-<UUID>

(At least when on a RAID1 configuration.)

andrewdavidwong · Jan 9, 2016

LUKS volumes on secondary internal disks are also treated the same way:

[user@dom0 ~]$ qvm-block -l
dom0:dm-2     luks-<UUID>

(At least when on a RAID1 configuration.)

Does anything bad happen if a user accidentally clicks on one of these options in the Qubes Manager "attach block devices" list?

If so, then I think this is pretty serious (but mainly a UI issue). It's very easy to slip and misclick something in the Qubes Manager menu, and the user currently has no way to protect themselves from such a mistake, even if they're fully aware that those options are things they never want to click. If there's any simple, easy-to-implement solution that allows users to hide all dom0 devices from this menu, or something like that, it would be a significant improvement.

andrewdavidwong · Jan 9, 2016

Does anything bad happen if a user accidentally clicks on one of these options in the Qubes Manager "attach block devices" list?

If so, then I think this is pretty serious (but mainly a UI issue). It's very easy to slip and misclick something in the Qubes Manager menu, and the user currently has no way to protect themselves from such a mistake, even if they're fully aware that those options are things they never want to click. If there's any simple, easy-to-implement solution that allows users to hide all dom0 devices from this menu, or something like that, it would be a significant improvement.

Potentially easier way to take care of this: Add a confirmation box.

Are you sure you want to attach <device-name> to <vm-name>?

andrewdavidwong · Jan 13, 2016

Potentially easier way to take care of this: Add a confirmation box.

Are you sure you want to attach <device-name> to <vm-name>?

I guess the RAID is /dev/md0 or sth like this, right? Devices used by anything theoretically shouldn't be included. It is checked based on /sys/block/sda/holders. But apparently there is a bug in that code...
Check in udev database: udevadm info -q all -n sda and look for QUBES_EXPOSED variable. If it is 0, but device is still visible, I think I know where the problem is.

marmarek · Jan 13, 2016

I guess the RAID is /dev/md0 or sth like this, right? Devices used by anything theoretically shouldn't be included. It is checked based on /sys/block/sda/holders. But apparently there is a bug in that code...
Check in udev database: udevadm info -q all -n sda and look for QUBES_EXPOSED variable. If it is 0, but device is still visible, I think I know where the problem is.

I guess the RAID is /dev/md0 or sth like this, right?

Yes, exactly.

Check in udev database: udevadm info -q all -n sda and look for QUBES_EXPOSED variable.

$ udevadm info -q all -n sda | grep QUBES_EXPOSED
E: QUBES_EXPOSED=1

andrewdavidwong · Jan 13, 2016

I guess the RAID is /dev/md0 or sth like this, right?

Yes, exactly.

Check in udev database: udevadm info -q all -n sda and look for QUBES_EXPOSED variable.

$ udevadm info -q all -n sda | grep QUBES_EXPOSED
E: QUBES_EXPOSED=1

On Tue, Jan 12, 2016 at 08:41:18PM -0800, Axon wrote:

$ udevadm info -q all -n sda | grep QUBES_EXPOSED
E: QUBES_EXPOSED=1

Is the array made of all the disk, or just some partition(s)? Check the
same for the partitions. This may be another case of 2nd point of
#1072 (comment)

Basically, the whole disk device (sda in this case) should not be
listed if any partition is busy, for whatever reason.

Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

marmarek · Jan 13, 2016

On Tue, Jan 12, 2016 at 08:41:18PM -0800, Axon wrote:

$ udevadm info -q all -n sda | grep QUBES_EXPOSED
E: QUBES_EXPOSED=1

Is the array made of all the disk, or just some partition(s)? Check the
same for the partitions. This may be another case of 2nd point of
#1072 (comment)

Basically, the whole disk device (sda in this case) should not be
listed if any partition is busy, for whatever reason.

Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

Is the array made of all the disk, or just some partition(s)?

Just some partitions.

Check the same for the partitions.

Indeed:

$ udevadm info -q all -n sda1 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sda2 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sda3 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sdb1 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sdb2 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sdb3 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0

andrewdavidwong · Jan 13, 2016

Is the array made of all the disk, or just some partition(s)?

Just some partitions.

Check the same for the partitions.

Indeed:

$ udevadm info -q all -n sda1 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sda2 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sda3 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sdb1 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sdb2 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0
$ udevadm info -q all -n sdb3 | grep QUBES_EXPOSED
E: QUBES_EXPOSED=0

Automated announcement from builder-github

The package qubes-utils-3.1.9-1.fc21 has been pushed to the r3.1 testing repository for the Fedora fc21 template.
To test this update, please install it with the following command:

sudo yum update --enablerepo=qubes-vm-r3.1-current-testing

QubesOS/qubes-issues

Join GitHub today

qvm-block treats system disks as attachable block devices #1600

Comments

andrewdavidwong commented Jan 9, 2016

This comment has been minimized.

andrewdavidwong commented Jan 9, 2016

This comment has been minimized.

andrewdavidwong commented Jan 9, 2016

This comment has been minimized.

andrewdavidwong commented Jan 13, 2016

marmarek added bug C: core P: major labels Jan 13, 2016

This comment has been minimized.

marmarek commented Jan 13, 2016

This comment has been minimized.

andrewdavidwong commented Jan 13, 2016

This comment has been minimized.

marmarek commented Jan 13, 2016

This comment has been minimized.

andrewdavidwong commented Jan 13, 2016

marmarek added a commit to marmarek/qubes-linux-utils that referenced this issue Jan 17, 2016

marmarek added this to the Release 3.0 updates milestone Mar 23, 2016

marmarek added a commit to QubesOS/qubes-linux-utils that referenced this issue May 1, 2016

marmarek closed this in marmarek/qubes-linux-utils@efd9854 May 16, 2016

marmarek added a commit to marmarek/old-qubes-core-admin that referenced this issue May 18, 2016

marmarek added a commit to QubesOS/qubes-core-admin that referenced this issue Jun 25, 2016

marmarek added a commit to QubesOS/qubes-linux-utils that referenced this issue Jun 25, 2016

This comment has been minimized.

marmarek commented Jun 25, 2016

marmarek added the r3.1-fc21-cur-test label Jun 25, 2016

This comment has been minimized.

marmarek commented Jun 25, 2016

marmarek added the r3.1-fc22-cur-test label Jun 25, 2016

This comment has been minimized.

marmarek commented Jun 25, 2016

marmarek added the r3.1-fc23-cur-test label Jun 25, 2016

This comment has been minimized.

marmarek commented Jun 25, 2016

marmarek added the r3.1-dom0-cur-test label Jun 25, 2016

This comment has been minimized.

marmarek commented Jun 25, 2016

marmarek added the r3.1-jessie-cur-test label Jun 25, 2016

This comment has been minimized.

marmarek commented Jun 25, 2016

marmarek added the r3.1-stretch-cur-test label Jun 25, 2016

This comment has been minimized.

marmarek commented Jun 25, 2016

marmarek added the r3.1-wheezy-cur-test label Jun 25, 2016

This comment has been minimized.

marmarek commented Jul 25, 2016

marmarek added r3.1-fc21-stable and removed r3.1-fc21-cur-test labels Jul 25, 2016

This comment has been minimized.

marmarek commented Jul 25, 2016

marmarek added r3.1-fc22-stable and removed r3.1-fc22-cur-test labels Jul 25, 2016

This comment has been minimized.

marmarek commented Jul 25, 2016

marmarek added r3.1-fc23-stable and removed r3.1-fc23-cur-test labels Jul 25, 2016

This comment has been minimized.

marmarek commented Jul 25, 2016

marmarek added r3.1-dom0-stable and removed r3.1-dom0-cur-test labels Jul 25, 2016

This comment has been minimized.

marmarek commented Jul 25, 2016

marmarek added r3.1-jessie-stable and removed r3.1-jessie-cur-test labels Jul 25, 2016

This comment has been minimized.

marmarek commented Jul 25, 2016

marmarek added r3.1-stretch-stable and removed r3.1-stretch-cur-test labels Jul 25, 2016

This comment has been minimized.

marmarek commented Jul 25, 2016

marmarek added r3.1-wheezy-stable and removed r3.1-wheezy-cur-test labels Jul 25, 2016

marmarek closed this in `marmarek/qubes-linux-utils@efd9854` May 16, 2016