Any way to attach a USB drive to a VM by label?

[Qubes Guy]

I've successfully used qvm-block (in Dom0) to attach USB drives to different VMs (persistently), but I've noticed that Qubes (or Linux) sometimes gives them to different devices over time. In other words, on Monday, my BIG_TOSHIBA drive will be on /dev/sda, but it'll be assigned to /dev/sdj when I boot up on Wednesday. This is throwing off my VeraCrypt / FreeFileSync backup routine. (Another way of saying this is if I say "qvm-block attach MyVM sys-usb:sda --persistent" when one of the three drives I use for MyVM is currently attached to that, this will fail if Qubes moves that drive to a different device-name (during boot) that isn't one of the three I previously attached (when I go to start up that VM).

I thought about persistently attaching all 10 of my USB drives to the VM (some HDs, some flash, one SSD - I never use all of them at once - don't ask!) because that would certainly fix this problem, but I get the following error when I try to start the VM: "ERROR: Start failed: XML error: target 'xvdi' duplicated for disk sources '/dev/sdc' and '/dev/sde', see /var/log/libvirt/libxl/libxl-driver.log for details".

Note that I did all the persistent attachment commands while the VM was not running. If I detach all those, start the VM, do the persistent attachments, shut down the VM and then restart it, I get an error along the lines of "qrexec process failed to respond in 60 seconds".

So, I guess I'm asking if there's a way to just persistently attach 2 or 3 external USB drives and have them consistently available on the same device names when I start the VM so VeraCrypt doesn't balk? (VeraCrypt ultimately doesn't care what device a drive is attached to (it could be sda - sdj on my system) because it shows the attached drive as "/media/user/BIG_TOSHIBA, but if a drive isn't where it's supposed to be, that'll fail.

In case you're curious, the error messages in /var/log/libvirt/libxl/libxl-driver.log are meaningless to me, but if you want me to post it, I can.

Any help you guys can give me would be greatly appreciated! Thanks...

[Qubes Guy]

By the way, I'm running version 4.0 of Qubes on a fairly recent laptop with 8GB of RAM...

[awokd]

On Fri, May 18, 2018 1:00 am, Qubes Guy wrote:
> On Thursday, May 17, 2018 at 8:57:09 PM UTC-4, Qubes Guy wrote:

>> So, I guess I'm asking if there's a way to just persistently attach 2 or
>> 3 external USB drives and have them consistently available on the same
>> device names when I start the VM so VeraCrypt doesn't balk? (VeraCrypt
>> ultimately doesn't care what device a drive is attached to (it could be
>> sda - sdj on my system) because it shows the attached drive as
>> "/media/user/BIG_TOSHIBA, but if a drive isn't where it's supposed to
>> be, that'll fail.

> By the way, I'm running version 4.0 of Qubes on a fairly recent laptop
> with 8GB of RAM...

Can you make sys-usb's /etc/fstab persistent, then specify /dev names
there by drive UUID?

[Qubes Guy]

I'm not sure what you mean by either of those things. Are you saying I should put entries in the fstab file in sys-usb to permanently mount those drives? If so, what would the commands look like? (As a side note, I tried to persistently mount a NAS share using the fstab file in my Debian template (and various other things) and couldn't get that to work, but I do know about the fstab file. I'm gonna try to use NFS instead...)

[Marek Marczykowski-Górecki]

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It isn't available yet, related issue:
https://github.com/QubesOS/qubes-issues/issues/3437

- --
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?
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[Qubes Guy]

So, the fix for this is coming? (Sorry, I can't speak the "Github" language too well yet.) I'm trying the method below, but running into the same kind of problems (so far) - qrexec non-responsiveness, sys-net no longer starting, etc

[Qubes Guy]

On Friday, May 18, 2018 at 2:19:09 PM UTC-4, Marek Marczykowski-Górecki wrote:

Oops, forgot the link: https://gist.github.com/etes/aa76a6e9c80579872e5f

[David Hobach]

On 05/18/2018 08:19 PM, Marek Marczykowski-Górecki wrote:
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>
> On Thu, May 17, 2018 at 05:57:09PM -0700, Qubes Guy wrote:
>> I've successfully used qvm-block (in Dom0) to attach USB drives to different VMs (persistently), but I've noticed that Qubes (or Linux) sometimes gives them to different devices over time. In other words, on Monday, my BIG_TOSHIBA drive will be on /dev/sda, but it'll be assigned to /dev/sdj when I boot up on Wednesday. This is throwing off my VeraCrypt / FreeFileSync backup routine. (Another way of saying this is if I say "qvm-block attach MyVM sys-usb:sda --persistent" when one of the three drives I use for MyVM is currently attached to that, this will fail if Qubes moves that drive to a different device-name (during boot) that isn't one of the three I previously attached (when I go to start up that VM).
>>
>> I thought about persistently attaching all 10 of my USB drives to the VM (some HDs, some flash, one SSD - I never use all of them at once - don't ask!) because that would certainly fix this problem, but I get the following error when I try to start the VM: "ERROR: Start failed: XML error: target 'xvdi' duplicated for disk sources '/dev/sdc' and '/dev/sde', see /var/log/libvirt/libxl/libxl-driver.log for details".
>>
>> Note that I did all the persistent attachment commands while the VM was not running. If I detach all those, start the VM, do the persistent attachments, shut down the VM and then restart it, I get an error along the lines of "qrexec process failed to respond in 60 seconds".
>>
>> So, I guess I'm asking if there's a way to just persistently attach 2 or 3 external USB drives and have them consistently available on the same device names when I start the VM so VeraCrypt doesn't balk? (VeraCrypt ultimately doesn't care what device a drive is attached to (it could be sda - sdj on my system) because it shows the attached drive as "/media/user/BIG_TOSHIBA, but if a drive isn't where it's supposed to be, that'll fail.
>>
>> In case you're curious, the error messages in /var/log/libvirt/libxl/libxl-driver.log are meaningless to me, but if you want me to post it, I can.
>>
>> Any help you guys can give me would be greatly appreciated! Thanks...
>
> It isn't available yet, related issue:
> https://github.com/QubesOS/qubes-issues/issues/3437

As a workaround you could mount the device via uuid or file system label
in sys-usb, create a loop device from the container you want to pass to
another VM and use qvm-block on that loop device (for which you can
define the name yourself).

Of course that's only convenient if you script it...

[Qubes Guy]

Thanks, but how do you do create a loop device? I'm (mostly) a Linux newbie (and, as of 5 weeks ago, I was a Qubes newbie) - I'm your worst nightmare :) I tried the UUID mount thing described in the article I mentioned above, but it just prevents sys-net from starting, but maybe with this loop thing you mention? Can you give me the actual commands required, or direct me to an article showing this? I'm not even sure what to search for. Thanks much!

[David Hobach]

Honestly you'll probably be off better by waiting for the feature to be
implemented then.

Anyway for reference I was talking about something like

in your sys-usb:
1. mount -U [uuid] [mount point]
2. losetup -f --show [your veracrypt file on the mounted file system]

in dom0:
3. qvm-block a [target VM] "sys-usb:[output of 2]"
4. Open the veracrypt block device now attached to [target VM]. (luks
supports that, not sure about veracrypt)

You can script all of that from dom0 using qvm-run. Essentially the idea
was to attach the Veracrypt file to [target VM] instead of attaching the
USB device itself.

qvm-block also supported files itself in 3.2 (i.e. 1. & 2. could be done
with qvm-block), but from my experience that didn't work so well in the
past.
In 4.0 it was then removed I think; qvm-block -p [target VM] [some file]
would have made for some really interesting applications such as the one
described above without much need for scripting.

[Qubes Guy]

Thank you. You might be right about waiting. I've already wasted too much time on this, but I'll take a look at it :) Thanks again

[Djon Snow]

суббота, 19 мая 2018 г., 16:37:55 UTC+3 пользователь Qubes Guy написал:

how to connect USB to standalone VM kali linux?