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184
common-tasks/backup-restore.md
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@ -11,96 +11,218 @@ redirect_from:
Qubes Backup, Restoration, and Migration
========================================
**Caution:** The Qubes backup system currently relies on a [weak key derivation scheme](https://github.com/QubesOS/qubes-issues/issues/971). It is *strongly recommended* that users select a *high-entropy* passphrase for use with Qubes backups.
**Caution:** The Qubes R3.2 backup system currently relies on a [weak key derivation scheme](https://github.com/QubesOS/qubes-issues/issues/971).
Although resolved in R4.0 and higher with the switch to scrypt, it is *strongly recommended* that users select a *high-entropy* passphrase for use with Qubes backups.
With Qubes, it's easy to back up and restore your whole system, as well as to migrate between two physical machines.
As of Qubes R2B3, these functions are integrated into the Qubes VM Manager GUI. There are also two command-line tools available which perform the same functions: [qvm-backup](/doc/dom0-tools/qvm-backup/) and [qvm-backup-restore](/doc/dom0-tools/qvm-backup-restore/).
As of Qubes R2B3, these functions are integrated into the Qubes VM Manager GUI.
There are also two command-line tools available which perform the same functions: [qvm-backup](/doc/dom0-tools/qvm-backup/) and [qvm-backup-restore](/doc/dom0-tools/qvm-backup-restore/).
Creating a Backup
Creating a Backup (R4.0 and later)
-----------------
1. In **Qubes VM Manager**, click **System** on the menu bar, then click **Backup VMs** in the drop-down list. This brings up the **Qubes Backup VMs** window.
1. Go to **Applications menu -> System Tools -> Backup Qubes**.
This brings up the **Qubes Backup VMs** window.
2. Move the VMs that you want to back up to the right-hand **Selected** column. VMs in the left-hand **Available** column will not be backed up.
2. Move the VMs that you want to back up to the right-hand **Selected** column.
VMs in the left-hand **Available** column will not be backed up.
**Note:** A VM must be shut down in order to be backed up. Currently running VMs appear in red.
You may choose whether to compress backups by checking or unchecking the **Compress the backup** box.
Normally this should be left on unless you have a specific reason otherwise.
Once you have selected all desired VMs, click **Next**.
3. Select the destination for the backup:
If you wish to send your backup to a (currently running) VM, select the VM in the drop-down box next to **Target AppVM**.
If you wish to send your backup to a [USB mass storage device](/doc/usb/), you can use the directory selection widget to mount a connected device (under "Other locations" item on the left); or first mount the device in a VM, then select the mount point inside that VM as the backup destination.
You must also specify a directory on the device or in the VM, or a command to be executed in the VM as a destination for your backup.
For example, if you wish to send your backup to the `~/backups` folder in the target VM, you would simply browse to it using the convenient directory selection dialog (`...`) at the right.
This destination directory must already exist.
If it does not exist, you must create it manually prior to backing up.
By specifying the appropriate directory as the destination in a VM, it is possible to send the backup directly to, e.g., a USB mass storage device attached to the VM.
Likewise, it is possible to enter any command as a backup target by specifying the command as the destination in the VM.
This can be used to send your backup directly to, e.g., a remote server using SSH.
**Note:** The supplied passphrase is used for **both** encryption/decryption and integrity verification.
At this point, you may also choose whether to save your settings by checking or unchecking the **Save settings as default backup profile** box.
**Warning: Saving the settings will result in your backup passphrase being saved in plaintext in dom0, so consider your threat model before checking this box.**
4. You will now see the summary of VMs to be backed up.
If there are any issues preventing the backup, they will be listed here and the **Next** button grayed out.
5. When you are ready, click **Next**.
Qubes will proceed to create your backup.
Once the progress bar has completed, you may click **Finish**.
Creating a Backup (R3.2 and earlier)
-----------------
1. In **Qubes VM Manager**, click **System** on the menu bar, then click **Backup VMs** in the drop-down list.
This brings up the **Qubes Backup VMs** window.
2. Move the VMs that you want to back up to the right-hand **Selected** column.
VMs in the left-hand **Available** column will not be backed up.
**Note:** A VM must be shut down in order to be backed up.
Currently running VMs appear in red.
Once you have selected all desired VMs, click **Next**.
3. Select the destination for the backup:
If you wish to send your backup to a (currently running) VM, select the VM in the drop-down box next to **Target AppVM**.
If you wish to send your backup to a [USB mass storage device](/doc/stick-mounting/), first mount the device in a VM, then select the mount point inside that VM as the backup destination.
If you wish to send your backup to a [USB mass storage device](/doc/usb/), you can use the directory selection widget to mount a connected device (under "Other locations" item on the left); or first mount the device in a VM, then select the mount point inside that VM as the backup destination.
You must also specify a directory on the device or in the VM, or a command to be executed in the VM as a destination for your backup. For example, if you wish to send your backup to the `~/backups` folder in the target VM, you would simply type `backups` in this field. This destination directory must already exist. If it does not exist, you must create it manually prior to backing up.
You must also specify a directory on the device or in the VM, or a command to be executed in the VM as a destination for your backup.
For example, if you wish to send your backup to the `~/backups` folder in the target VM, you would simply browse to it using the convenient directory selection dialog (`...`) at the right.
If it does not exist, you must create it manually prior to backing up.
By specifying the appropriate directory as the destination in a VM, it is possible to send the backup directly to, e.g., a USB mass storage device attached to the VM. Likewise, it is possible to enter any command as a backup target by specifying the command as the destination in the VM. This can be used to send your backup directly to, e.g., a remote server using SSH.
By specifying the appropriate directory as the destination in a VM, it is possible to send the backup directly to, e.g., a USB mass storage device attached to the VM.
Likewise, it is possible to enter any command as a backup target by specifying the command as the destination in the VM.
This can be used to send your backup directly to, e.g., a remote server using SSH.
At this point, you must also choose whether to encrypt your backup by checking or unchecking the **Encrypt backup** box.
**Note:** It is strongly recommended that you opt to encrypt all backups which will be sent to untrusted destinations!
**Note:** The supplied passphrase is used for **both** encryption/decryption and integrity verification. If you decide not to encrypt your backup (by unchecking the **Encrypt backup** box), the passphrase you supply will be used **only** for integrity verification. If you supply a passphrase but do not check the **Encrypt backup** box, your backup will **not** be encrypted!
**Note:** The supplied passphrase is used for **both** encryption/decryption and integrity verification.
If you decide not to encrypt your backup (by unchecking the **Encrypt backup** box), the passphrase you supply will be used **only** for integrity verification.
If you supply a passphrase but do not check the **Encrypt backup** box, your backup will **not** be encrypted!
4. When you are ready, click **Next**. Qubes will proceed to create your backup. Once the progress bar has completed, you may click **Finish**.
4. You will now see the summary of VMs to be backed up.
If there are any issues preventing the backup, they will be listed here and the **Next** button grayed out.
5. When you are ready, click **Next**.
Qubes will proceed to create your backup.
Once the progress bar has completed, you may click **Finish**.
Restoring from a Backup
Restoring from a Backup (R4.0 and later)
-----------------------
1. In **Qubes VM Manager**, click **System** on the menu bar, then click **Restore VMs from backup** in the drop-down list. This brings up the **Qubes Restore VMs** window.
1. Go to **Applications menu -> System Tools -> Restore Backup**.
This brings up the **Qubes Restore VMs** window.
2. Select the source location of the backup to be restored:
- If your backup is located on a [USB mass storage device](/doc/stick-mounting/), select the device in the drop-down box next to **Device**.
- If your backup is located on a [USB mass storage device](/doc/usb/), attach it first to another VM or select `sys-usb` in the next item.
- If your backup is located in a (currently running) VM, select the VM in the drop-down box next to **AppVM**.
You must also specify the directory in which the backup resides (or a command to be executed in a VM). If you followed the instructions in the previous section, "Creating a Backup," then your backup is most likely in the location you chose as the destination in step 3. For example, if you had chosen the `~/backups` directory of a VM as your destination in step 3, you would now select the same VM and again type `backups` into the **Backup directory** field.
**Note:** After you have typed the directory location of the backup in the **Backup directory** field, click the ellipsis button `...` to the right of the field.
You must also specify the directory and filename of the backup (or a command to be executed in a VM) in the **Backup file** field.
If you followed the instructions in the previous section, "Creating a Backup," then your backup is most likely in the location you chose as the destination in step 3.
For example, if you had chosen the `~/backups` directory of a VM as your destination in step 3, you would now select the same VM and again browse to (using `...`) the `backups` folder.
Once you've located the backup file, double-click it or select it and hit **OK**.
3. There are three options you may select when restoring from a backup:
1. **ignore missing**: If any of the VMs in your backup depended upon a NetVM, ProxyVM, or TemplateVM that is not present in (i.e., "missing from") the current system, checking this box will ignore the fact that they are missing and restore the VMs anyway.
2. **ignore username mismatch**: This option applies only to the restoration of dom0's home directory. If your backup was created on a Qubes system which had a different dom0 username than the dom0 username of the current system, then checking this box will ignore the mismatch between the two usernames and proceed to restore the home directory anyway.
3. **skip dom0**: If this box is checked, dom0's home directory will not be restored from your backup.
1. **ignore missing templates and net VMs**: If any of the VMs in your backup depended upon a NetVM or TemplateVM that is not present in (i.e., "missing from") the current system, checking this box will ignore the fact that they are missing and restore the VMs anyway and set them to use the default NetVM and system default template.
2. **ignore username mismatch**: This option applies only to the restoration of dom0's home directory.
If your backup was created on a Qubes system which had a different dom0 username than the dom0 username of the current system, then checking this box will ignore the mismatch between the two usernames and proceed to restore the home directory anyway.
3. **Verify backup integrity, do not restore the data**: This will scan the backup file for corrupted data.
However, it does not currently detect if it is missing data as long as it is a correctly structured, non-corrupted backup file.
See [issue #3498](https://github.com/QubesOS/qubes-issues/issues/3498) for more details.
4. If your backup is encrypted, you must check the **Encrypted backup** box. If a passphrase was supplied during the creation of your backup (regardless of whether it is encrypted), then you must supply it here.
4. If your backup is encrypted, you must check the **Encrypted backup** box.
If a passphrase was supplied during the creation of your backup (regardless of whether it is encrypted), then you must supply it here.
**Note:** The passphrase which was supplied when the backup was created was used for **both** encryption/decryption and integrity verification. If the backup was not encrypted, the supplied passphrase is used only for integrity verification.
**Note:** The passphrase which was supplied when the backup was created was used for **both** encryption/decryption and integrity verification.
If the backup was not encrypted, the supplied passphrase is used only for integrity verification.
All backups made from a Qubes R4.0 system will be encrypted.
**Note:** A VM cannot be restored from a backup if a VM with the same name already exists on the current system. You must first remove or change the name of any VM with the same name in order to restore such a VM.
5. You will now see the summary of VMs to be restored.
If there are any issues preventing the restore, they will be listed here and the **Next** button grayed out.
5. When you are ready, click **Next**. Qubes will proceed to restore from your backup. Once the progress bar has completed, you may click **Finish**.
6. When you are ready, click **Next**.
Qubes will proceed to restore from your backup.
Once the progress bar has completed, you may click **Finish**.
Restoring from a Backup (R3.2 and earlier)
-----------------------
1. In **Qubes VM Manager**, click **System** on the menu bar, then click **Restore VMs from backup** in the drop-down list.
This brings up the **Qubes Restore VMs** window.
2. Select the source location of the backup to be restored:
- If your backup is located on a [USB mass storage device](/doc/usb/), attach it first to another VM or select `sys-usb` in the next item.
- If your backup is located in a (currently running) VM, select the VM in the drop-down box next to **AppVM**.
You must also specify the directory and filename of the backup (or a command to be executed in a VM) in the **Backup file** field.
If you followed the instructions in the previous section, "Creating a Backup," then your backup is most likely in the location you chose as the destination in step 3.
For example, if you had chosen the `~/backups` directory of a VM as your destination in step 3, you would now select the same VM and again browse to (using `...`) the `backups` folder.
Once you've located the backup file, double-click or select it and hit **OK**.
3. There are three options you may select when restoring from a backup:
1. **ignore missing**: If any of the VMs in your backup depended upon a NetVM, ProxyVM, or TemplateVM that is not present in (i.e., "missing from") the current system, checking this box will ignore the fact that they are missing and restore the VMs anyway and set them to use the default NetVM and system default template.
2. **ignore username mismatch**: This option applies only to the restoration of dom0's home directory.
If your backup was created on a Qubes system which had a different dom0 username than the dom0 username of the current system, then checking this box will ignore the mismatch between the two usernames and proceed to restore the home directory anyway.
3. **Verify backup integrity, do not restore the data**: This will scan the backup file for corrupted data.
However, it does not currently detect if it is missing data as long as it is a correctly structured, non-corrupted backup file. See [issue #3498](https://github.com/QubesOS/qubes-issues/issues/3498) for more details.
4. If your backup is encrypted, you must check the **Encrypted backup** box.
If a passphrase was supplied during the creation of your backup (regardless of whether it is encrypted), then you must supply it here.
**Note:** The passphrase which was supplied when the backup was created was used for **both** encryption/decryption and integrity verification.
If the backup was not encrypted, the supplied passphrase is used only for integrity verification.
**Note:** A VM cannot be restored from a backup if a VM with the same name already exists on the current system.
You must first remove or change the name of any VM with the same name in order to restore such a VM.
5. You will now see the summary of VMs to be restored.
If there are any issues preventing the restore, they will be listed here and the **Next** button grayed out.
6. When you are ready, click **Next**.
Qubes will proceed to restore from your backup.
Once the progress bar has completed, you may click **Finish**.
Emergency Backup Recovery without Qubes
---------------------------------------
The Qubes backup system has been designed with emergency disaster recovery in mind. No special Qubes-specific tools are required to access data backed up by Qubes. In the event a Qubes system is unavailable, you can access your data on any GNU/Linux system with the following procedure.
The Qubes backup system has been designed with emergency disaster recovery in mind.
No special Qubes-specific tools are required to access data backed up by Qubes.
In the event a Qubes system is unavailable, you can access your data on any GNU/Linux system with the following procedure.
For emergency restore of backup created on Qubes R2 or newer take a look [here](/doc/backup-emergency-restore-v3/). For backups created on earlier Qubes versions, take a look [here](/doc/backup-emergency-restore-v2/).
Refer to the following for emergency restore of a backup created on:
* [Qubes R4 or newer](/doc/backup-emergency-restore-v4/)
* [Qubes R3](/doc/backup-emergency-restore-v3/)
* [Qubes R2 or older](/doc/backup-emergency-restore-v2/)
Migrating Between Two Physical Machines
---------------------------------------
In order to migrate your Qubes system from one physical machine to another, simply follow the backup procedure on the old machine, [install Qubes](/downloads/) on the new machine, and follow the restoration procedure on the new machine. All of your settings and data will be preserved!
In order to migrate your Qubes system from one physical machine to another, simply follow the backup procedure on the old machine, [install Qubes](/downloads/) on the new machine, and follow the restoration procedure on the new machine.
All of your settings and data will be preserved!
Choosing a Backup Passphrase
----------------------------
Here are some things to consider when selecting a passphrase for your backups:
* If you plan to store the backup for a long time or on third-party servers, you should make sure to use a very long, high-entropy passphrase. (Depending on the decryption passphrase you use for your system drive, this may necessitate selecting a stronger passphrase. If your system drive decryption passphrase is already sufficiently strong, it may not.)
* An adversary who has access to your backups may try to substitute one backup for another. For example, when you attempt to retrieve a recent backup, the adversary may instead give you a very old backup containing a compromised VM. If you're concerned about this type of attack, you may wish to use a different passphrase for each backup, e.g., by appending a number or date to the passphrase.
* If you're forced to enter your system drive decryption passphrase in plain view of others (where it can be shoulder-surfed), then you may want to use a different passphrase for your backups (even if your system drive decryption passphrase is already maximally strong). On the other hand, if you're careful to avoid shoulder-surfing and/or have a passphrase that's difficult to detect via shoulder-surfing, then this may not be a problem for you.
* If you plan to store the backup for a long time or on third-party servers, you should make sure to use a very long, high-entropy passphrase.
(Depending on the decryption passphrase you use for your system drive, this may necessitate selecting a stronger passphrase.
If your system drive decryption passphrase is already sufficiently strong, it may not.)
* An adversary who has access to your backups may try to substitute one backup for another.
For example, when you attempt to retrieve a recent backup, the adversary may instead give you a very old backup containing a compromised VM.
If you're concerned about this type of attack, you may wish to use a different passphrase for each backup, e.g., by appending a number or date to the passphrase.
* If you're forced to enter your system drive decryption passphrase in plain view of others (where it can be shoulder-surfed), then you may want to use a different passphrase for your backups (even if your system drive decryption passphrase is already maximally strong).
On the other hand, if you're careful to avoid shoulder-surfing and/or have a passphrase that's difficult to detect via shoulder-surfing, then this may not be a problem for you.
Notes
-----
* The Qubes backup system relies on `openssl enc`, which is known to use a very weak key derivation scheme. The Qubes backup system also uses the same passphrase for authentication and for encryption, which is problematic from a security perspective. Users are advised to use a very high entropy passphrase for Qubes backups. For a full discussion, see [this ticket](https://github.com/QubesOS/qubes-issues/issues/971) and [this thread](https://groups.google.com/d/msg/qubes-devel/CZ7WRwLXcnk/u_rZPoVxL5IJ).
* The Qubes R3.2 and earlier backup system relies on `openssl enc`, which is known to use a very weak key derivation scheme.
The Qubes backup system also uses the same passphrase for authentication and for encryption, which is problematic from a security perspective.
Users are advised to use a very high entropy passphrase for Qubes backups.
For a full discussion, see [this ticket](https://github.com/QubesOS/qubes-issues/issues/971) and [this thread](https://groups.google.com/d/msg/qubes-devel/CZ7WRwLXcnk/u_rZPoVxL5IJ).
* For the technical details of the backup system, please refer to [this thread](https://groups.google.com/d/topic/qubes-devel/TQr_QcXIVww/discussion).
* If working with symlinks, note the issues described in [this thread](https://groups.google.com/d/topic/qubes-users/EITd1kBHD30/discussion).

29
common-tasks/copying-files.md
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@ -19,20 +19,36 @@ In order to copy file(s) from qube A to qube B, follow these steps:
GUI
---
1. Open file manager in the source qube (qube A), choose file(s) that you wish to copy, and right click on the selection, and choose `Copy to another AppVM`
1. Open file manager in the source qube (qube A), choose file(s) that you wish to copy, and right click on the selection, and choose `Copy to another AppVM`
1. A dialog box will appear asking for the name of the destination qube (qube B).
2. A dialog box will appear asking for the name of the destination qube (qube B).
1. A confirmation dialog box will appear(this will be displayed by Dom0, so none of the qubes can fake your consent). After you click ok, qube B will be started if it is not already running, the file copy operation will start, and the files will be copied into the following folder in qube B:
3. A confirmation dialog box will appear(this will be displayed by Dom0, so none of the qubes can fake your consent). After you click ok, qube B will be started if it is not already running, the file copy operation will start, and the files will be copied into the following folder in qube B:
- `/home/user/QubesIncoming/<source>`
`/home/user/QubesIncoming/<source>`
4. You can now move them whenever you like in the qube B filesystem using the file manager there.
1. You can now move them whenever you like in the qube B filesystem using the file manager there.
CLI
---
[qvm-copy-to-vm](/doc/vm-tools/qvm-copy-to-vm/)
```
qvm-copy-to-vm [--without-progress] dest_vmname file [file]+
```
Also see: [qvm-copy-to-vm](/doc/vm-tools/qvm-copy-to-vm/)
Qubes 4.0
---------
In Qubes 4.0, qvm-copy-to-vm and qvm-move-to-vm are deprecated (GUI behaviour is unchanged from Qubes 3.2). In the command line, use qvm-copy or qvm-move to avoid typing target qube name twice.
```
qvm-copy [--without-progress] file [file]+
```
On inter-qube file copy security
----------------------------------
@ -44,3 +60,4 @@ However, one should keep in mind that performing a data transfer from *less trus
See also [this article](https://blog.invisiblethings.org/2011/03/13/partitioning-my-digital-life-into.html) for more information on this topic, and some ideas of how we might solve this problem in some future version of Qubes.
You may also want to read how to [revoke "Yes to All" authorization](/doc/qrexec3/#revoking-yes-to-all-authorization)

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common-tasks/dispvm.md
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@ -11,74 +11,95 @@ redirect_from:
Disposable VMs (DispVMs)
========================
Background
----------
A Disposable VM (DispVM) is a lightweight VM that can be created quickly and will disappear when closed.
Disposable VMs are usually created in order to host a single application, like a viewer, editor, or web browser.
Changes made to a file opened in a Disposable VM are passed back to the originating VM.
This means that you can safely work with untrusted files without risk of compromising your other VMs.
DispVMs can be created either directly from Dom0 or from within AppVMs.
Once a DispVM has been created it will appear in Qubes VM Manager with the name "dispX".
A Disposable VM (DispVM) is a lightweight VM that can be created quickly and which will disappear when it is finished with. Usually a Disposable VM is created in order to host a single application, like a viewer or an editor. This means that you can safely work with files without risk of compromising any of your VMs. Changes made to a file opened in a disposable VM are passed back to the originating VM. See [this article](https://blog.invisiblethings.org/2010/06/01/disposable-vms.html) for more on why would one want to use a Disposable VM.
See [this article](https://blog.invisiblethings.org/2010/06/01/disposable-vms.html) for more on why one would want to use a Disposable VM.
By default a DispVM will inherit the NetVM and firewall settings of the ancestor VM, that is the VM it is launched from. Thus if an AppVM uses sys-net as NetVM (instead of, say, sys-whonix), any DispVM launched from this AppVM will also have sys-net as its NetVM. You can change this behaviour for individual VMs: in Qubes VM Manager open VM Settings for the VM in question and go to the "Advanced" tab. Here you can edit the "NetVM for DispVM" setting to change the NetVM of any DispVM launched from that VM.
Disposable VMs and Networking
-----------------------------
A DispVM launched from the Start Menu inherits the NetVM of the [DVM Template](https://www.qubes-os.org/doc/glossary/#dvm-template). By default it is named `fedora-XX-dvm` (where `XX` is the Fedora version of the default TemplateVM) and, as a so-called internal VM, hidden in Qubes VM Manager; it can be shown by selecting "Show/Hide internal VMs". Notice that changing the "NetVM for DispVM" setting for the DVM Template does *not* affect the NetVM of DispVMs launched from the Start Menu; only changing the DVM Template's own NetVM does.
NetVM and firewall rules for Disposable VMs can be set as they can for a normal VM.
By default a DispVM will inherit the NetVM and firewall settings of the VM from which it is launched.
Thus if an AppVM uses sys-net as its NetVM, any DispVM launched from this AppVM will also have sys-net as its NetVM.
You can change this behaviour for individual VMs: in Qubes VM Manager open VM Settings for the VM in question and go to the "Advanced" tab.
Here you can edit the "NetVM for DispVM" setting to change the NetVM of any DispVM launched from that VM.
Once a DispVM has been created it will appear in Qubes VM Manager with the name "dispX", and NetVM and firewall rules can be set as for a normal VM.
A Disposable VM launched from the Start Menu inherits the NetVM of the [DVM Template](/doc/glossary/#dvm-template).
By default the DVM template is called `fedora-XX-dvm` (where `XX` is the Fedora version of the default TemplateVM).
As an "internal" VM it is hidden in Qubes VM Manager, but can be shown by selecting "Show/Hide internal VMs".
Note that changing the "NetVM for DispVM" setting for the DVM Template does *not* affect the NetVM of DispVMs launched from the Start Menu; only changing the DVM Template's own NetVM does.
Opening a file in a Disposable VM via GUI
-----------------------------------------
Opening a file in a Disposable VM (via GUI)
-------------------------------------------
In some AppVM, right click on the file you wish to open in a Disposable VM (in the Nautilus file manager), then choose "Open in Disposable VM". Wait a few seconds and the default application for this file type should appear displaying the file content. This app is running in a whole new VM -- a disposable VM created for the purpose of viewing or editing this very file. Once you close the viewing application the whole Disposable VM will be destroyed. If you have edited the file and saved the changes the changed file will be saved back to the original VM, overwriting the original.
In an AppVM's file manager, right click on the file you wish to open in a Disposable VM, then choose "Open in Disposable VM".
Wait a few seconds and the default application for this file type should appear displaying the file content.
This app is running in its own dedicated VM -- a Disposable VM created for the purpose of viewing or editing this very file.
Once you close the viewing application the whole Disposable VM will be destroyed.
If you have edited the file and saved the changes, the changed file will be saved back to the original AppVM, overwriting the original.
![r1-open-in-dispvm-1.png](/attachment/wiki/DisposableVms/r1-open-in-dispvm-1.png) ![r1-open-in-dispvm-2.png](/attachment/wiki/DisposableVms/r1-open-in-dispvm-2.png)
Opening a fresh web browser instance in a new Disposable VM
-----------------------------------------------------------
Sometimes it is convenient to open a fresh instance of Firefox within a new fresh Disposable VM. This can be easily done by using the Start Menu: just go to Start -\> System Tools -\> DispVM:Firefox web browser . Wait a few seconds until a web browser starts. Once you close the viewing application the whole Disposable VM will get destroyed.
Sometimes it is desirable to open an instance of Firefox within a new fresh Disposable VM.
This can be done easily using the Start Menu: just go to Start -\> System Tools -\> DispVM:Firefox web browser.
Wait a few seconds until a web browser starts.
Once you close the viewing application the whole Disposable VM will be destroyed.
![r1-open-in-dispvm-3.png](/attachment/wiki/DisposableVms/r1-open-in-dispvm-3.png)
Opening a file in a Disposable VM via command line (from AppVM)
---------------------------------------------------------------
Use the `qvm-open-in-dvm` command line (from your AppVM), e.g.:
Use the `qvm-open-in-dvm` command from a terminal in your AppVM:
~~~
[user@work-pub ~]$ qvm-open-in-dvm Downloads/apple-sandbox.pdf
~~~
The qvm-open-in-dvm will not exit until you close the application in the Disposable VM.
Starting an arbitrary application in a disposable VM via command line (from Dom0)
---------------------------------------------------------------------------------
**Note:** Normally there should be no need for doing this -- this is just for Qubes hackers ;)
~~~
[joanna@dom0 ~]$ echo xterm | /usr/lib/qubes/qfile-daemon-dvm qubes.VMShell dom0 DEFAULT red
~~~
In fact the Disposable VM appmenu used for starting Firefox contains a very similar command to the above. Please note, however, that it generally makes little sense to start any other application other than a Web Browser this way...
Note that the `qvm-open-in-dvm` process will not exit until you close the application in the Disposable VM.
Starting an arbitrary program in a Disposable VM from an AppVM
--------------------------------------------------------------
Sometimes it might be useful to start an arbitrary program, such as e.g. terminal in an Disposable VM from an AppVM. This could be simply done this way:
Sometimes it can be useful to start an arbitrary program in a DispVM. This can be done from an AppVM by running
~~~
[user@vault ~]$ qvm-run '$dispvm' xterm
~~~
Note the above command is issued in an AppVM, not in Dom0. The created Disposable VM can be normally accessed via other tools, such as e.g. `qvm-copy-to-vm`, using its 'dispX' name, as shown by the Qubes Manager or `qvm-ls` tools.
The created Disposable VM can be accessed via other tools (such as `qvm-copy-to-vm`) using its "dispX" name as shown in the Qubes Manager or `qvm-ls`.
Starting an arbitrary application in a Disposable VM via command line (from Dom0)
---------------------------------------------------------------------------------
The Start Menu has shortcuts for opening a terminal and a web browser in dedicated DispVMs, since these are very common tasks.
However, it is possible to start an arbitrary application in a DispVM directly from Dom0 by running
~~~
[joanna@dom0 ~]$ echo xterm | /usr/lib/qubes/qfile-daemon-dvm qubes.VMShell dom0 DEFAULT red
~~~
(The Disposable VM appmenu used for starting Firefox runs a very similar command to the one above.)
Customizing Disposable VMs
---------------------------------------------------------
You can change the template used to generate the Disposable VM, and change settings used in the Disposable VM savefile. These changes will be reflected in every new Disposable VM.
Full instructions are [here](/doc/dispvm-customization/)
--------------------------
You can change the template used to generate the Disposable VM, and change settings used in the Disposable VM savefile.
These changes will be reflected in every new Disposable VM.
Full instructions can be found [here](/doc/dispvm-customization/).
Disposable VMs and Local Forensics
----------------------------------
At this time, DispVMs should not be relied upon to circumvent local forensics, as they do not run entirely in RAM. For details, see [this thread](https://groups.google.com/d/topic/qubes-devel/QwL5PjqPs-4/discussion).
At this time, DispVMs should not be relied upon to circumvent local forensics, as they do not run entirely in RAM.
For details, see [this thread](https://groups.google.com/d/topic/qubes-devel/QwL5PjqPs-4/discussion).
When it is essential to avoid leaving any trace, consider using [Tails](https://tails.boum.org/).

24
common-tasks/software-update-dom0.md
View file

@ -14,7 +14,7 @@ Updating software in dom0
Why would one want to update software in dom0?
----------------------------------------------
Normally, there should be few reasons for updating software in dom0. This is because there is no networking in dom0, which means that even if some bugs are discovered e.g. in the dom0 Desktop Manager, this really is not a problem for Qubes, because none of the 3rd party software running in dom0 is accessible from VMs or the network in any way. Some exceptions to this include: Qubes GUI daemon, Xen store daemon, and disk back-ends. (We plan to move the disk backends to an untrusted domain in a future Qubes release) Of course, we believe this software is reasonably secure, and we hope it will not need patching.
Normally, there should be few reasons for updating software in dom0. This is because there is no networking in dom0, which means that even if some bugs are discovered e.g. in the dom0 Desktop Manager, this really is not a problem for Qubes, because none of the third-party software running in dom0 is accessible from VMs or the network in any way. Some exceptions to this include: Qubes GUI daemon, Xen store daemon, and disk back-ends. (We plan move the disk backends to an untrusted domain in a future Qubes release.) Of course, we believe this software is reasonably secure, and we hope it will not need patching.
However, we anticipate some other situations in which updating dom0 software might be necessary or desirable:
@ -58,12 +58,12 @@ Of course, command line tools are still available for accomplishing various upda
sudo qubes-dom0-update package-version
~~~
Yum will say that there is no update, but the package will nonetheless be downloaded to dom0.
Dnf will say that there is no update, but the package will nonetheless be downloaded to dom0.
2. Downgrade the package:
~~~
sudo yum downgrade package-version
sudo dnf downgrade package-version
~~~
### How to re-install a package
@ -76,21 +76,21 @@ You can re-install in a similar fashion to downgrading.
sudo qubes-dom0-update package
~~~
Yum will say that there is no update, but the package will nonetheless be downloaded to dom0.
Dnf will say that there is no update, but the package will nonetheless be downloaded to dom0.
2. Re-install the package:
~~~
sudo yum reinstall package
sudo dnf reinstall package
~~~
Note that yum will only re-install if the installed and downloaded versions match. You can ensure they match by either updating the package to the latest version, or specifying the package version in the first step using the form `package-version`.
Note that Dnf will only re-install if the installed and downloaded versions match. You can ensure they match by either updating the package to the latest version, or specifying the package version in the first step using the form `package-version`.
### How to uninstall a package
If you've installed a package such as anti-evil-maid, you can remove it with the following command:
sudo yum remove anti-evil-maid
sudo dnf remove anti-evil-maid
### Testing repositories
@ -124,8 +124,16 @@ is needed for the VMs. (Note that the following example enables the unstable rep
sudo qubes-dom0-update --enablerepo=qubes-dom0-unstable kernel kernel-qubes-vm
~~~
Rebuild grub config.
If the update process does not automatically do it (you should see it mentioned in the CLI output
from the update command), you may need to manually rebuild the EFI or grub config depending on which
your system uses.
EFI (Replace the file names with the correct versions for your updated kernel)
~~~
sudo /usr/bin/dracut -f /boot/efi/EFI/qubes/initramfs-4.4.31-11.pvops.qubes.x86_64.img 4.4.31-11.pvops.qubes.x86_64
~~~
Grub2
~~~
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
~~~

35
common-tasks/software-update-vm.md
View file

@ -18,20 +18,24 @@ Most of the AppVMs (domains) are based on a *TemplateVM*, which means that their
In addition to saving on the disk space, and reducing domain creation time, another advantage of such scheme is the possibility for centralized software update. It's just enough to do the update in the template VM, and then all the AppVMs based on this template get updates automatically after they are restarted.
The default template is called **fedora-14-x64** in Qubes R1 and **fedora-20-x64** in Qubes R2.
The default template is called **fedora-23** in Qubes R3.2 and **fedora-26** in Qubes R4.0.
The side effect of this mechanism is, of course, that if you install any software in your AppVM, more specifically in any directory other than `/home` or `/usr/local` then it will disappear after the AppVM reboot (as the root filesystem for this AppVM will again be "taken" from the TemplateVM). **This means one normally installs software in the TemplateVM, not in AppVMs.**
The side effect of this mechanism is, of course, that if you install any software in your AppVM, more specifically in any directory other than `/home`, `/usr/local`, or `/rw` then it will disappear after the AppVM reboots (as the root filesystem for this AppVM will again be "taken" from the TemplateVM). **This means one normally installs software in the TemplateVM, not in AppVMs.**
Unlike VM private filesystems, the template VM root filesystem does not support discard, so deleting files does not free the space in dom0. See [these instructions](/doc/template/fedora/upgrade-23-to-24/#compacting-the-upgraded-template) to recover space in dom0.
Unlike VM private filesystems, under R3.x the template VM root filesystem does not support discard by default, so deleting files does not free the space in dom0. See [these instructions](/doc/template/fedora/upgrade-23-to-24/#compacting-the-upgraded-template) to recover space in dom0.
In R4.0 and higher, the template root filesystem is created in a thin pool so manual trims are no longer needed.
See [here](/doc/disk-trim) for further discussion on enabling discards/trim support under all versions.
Installing (or updating) software in the TemplateVM
----------------------------------------------------
In order to permanently install new software, you should:
- Start the template VM and then start either console (e.g. `gnome-terminal`) or dedicated software management application, such as `gpk-application` (*Start-\>Applications-\>Template: fedora-XX-x64-\>Add/Remove software*),
- Start the template VM and then start either console (e.g. `gnome-terminal`) or dedicated software management application, such as `gpk-application` (*Start-\>Applications-\>Template: fedora-XX-\>Add/Remove software*),
- Install/update software as usual (e.g. using yum, or the dedicated GUI application). Then, shutdown the template VM,
- Install/update software as usual (e.g. using dnf, or the dedicated GUI application). Then, shutdown the template VM,
- You will see now that all the AppVMs based on this template (by default all your VMs) will be marked as "outdated" in the manager. This is because their filesystems have not been yet updated -- in order to do that, you must restart each VM. You don't need to restart all of them at the same time -- e.g. if you just need the newly installed software to be available in your 'personal' domain, then restart only this VM. You can restart others whenever this will be convenient to you.
@ -73,9 +77,14 @@ Debian also has three Qubes VM testing repositories (where `*` denotes the Relea
repository; mostly experimental debugging packages
To enable or disable any of these repos permanently, uncomment the corresponding `deb` line in
`/etc/apt/sources.list.d/qubes-r3.list`
`/etc/apt/sources.list.d/qubes-r*.list`
Reverting changes to a TemplateVM
Reverting changes to a TemplateVM (R4.0)
---------------------------------
TBD- Qubes 4.0 uses a CoW system that permits snapshotting. To revert changes, one would...
Reverting changes to a TemplateVM (R3.2)
---------------------------------
Perhaps you've just updated your TemplateVM, and the update broke your template.
@ -123,7 +132,7 @@ There are several ways to deal with this problem:
Some popular questions:
- So, why should we actually trust Fedora repos -- it also contains large amount of 3rd party software that might buggy, right?
- So, why should we actually trust Fedora repos -- it also contains large amount of third-party software that might buggy, right?
As far as the template's compromise is concerned, it doesn't really matter whether /usr/bin/firefox is buggy and can be exploited, or not. What matters is whether its *installation* scripts (such as %post in the rpm.spec) are benign or not. Template VM should be used only for installation of packages, and nothing more, so it should never get a chance to actually run the /usr/bin/firefox and get infected from it, in case it was compromised. Also, some of your more trusted AppVMs, would have networking restrictions enforced by the [firewall VM](/doc/firewall/), and again they should not fear this proverbial /usr/bin/firefox being potentially buggy and easy to compromise.
@ -168,14 +177,14 @@ qvm-create <vmname> --template <templatename> --label <label>
Temporarily allowing networking for software installation
---------------------------------------------------------
Some 3rd party applications cannot be installed using the standard yum repositories, and need to be manually downloaded and installed. When the installation requires internet connection to access 3rd party repositories, it will naturally fail when run in a Template VM because the default firewall rules for templates only allow connections to standard yum repositories. So it is necessary to modify firewall rules to allow less restrictive internet access for the time of the installation, if one really wants to install those applications into a template. As soon as software installation is completed, firewall rules should be returned back to the default state. The user should decide by themselves whether such 3rd party applications should be equally trusted as the ones that come from the standard Fedora signed repositories and whether their installation will not compromise the default Template VM, and potentially consider installing them into a separate template or a standalone VM (in which case the problem of limited networking access doesn't apply by default), as described above.
Some third-party applications cannot be installed using the standard yum repositories, and need to be manually downloaded and installed. When the installation requires internet connection to access third-party repositories, it will naturally fail when run in a Template VM because the default firewall rules for templates only allow connections to standard yum repositories. So it is necessary to modify firewall rules to allow less restrictive internet access for the time of the installation, if one really wants to install those applications into a template. As soon as software installation is completed, firewall rules should be returned back to the default state. The user should decide by themselves whether such third-party applications should be equally trusted as the ones that come from the standard Fedora signed repositories and whether their installation will not compromise the default Template VM, and potentially consider installing them into a separate template or a standalone VM (in which case the problem of limited networking access doesn't apply by default), as described above.
Updates proxy
Updates proxy (some content applies only to versions earlier than R3.2)
-------------
Updates proxy is a service which filters http access to allow access to only something that looks like a yum or apt repository. This is meant to mitigate user errors (like using browser in the template VM), rather than some real isolation. It is done with http proxy instead of simple firewall rules because it is hard to list all the repository mirrors (and keep that list up to date). The proxy is used only to filter the traffic, not to cache anything.
The proxy is running in selected VMs (by default all the NetVMs (1)) and intercepts traffic directed to 10.137.255.254:8082. Thanks to such configuration all the VMs can use the same proxy address, and if there is a proxy on network path, it will handle the traffic (of course when firewall rules allow that). If the VM is configured to have access to the updates proxy (2), the startup scripts will automatically configure yum to really use the proxy (3). Also access to updates proxy is independent of any other firewall settings (VM will have access to updates proxy, even if policy is set to block all the traffic).
The proxy is running in selected VMs (by default all the NetVMs (1)) and intercepts traffic directed to 10.137.255.254:8082. Thanks to such configuration all the VMs can use the same proxy address, and if there is a proxy on network path, it will handle the traffic (of course when firewall rules allow that). If the VM is configured to have access to the updates proxy (2), the startup scripts will automatically configure dnf to really use the proxy (3). Also access to updates proxy is independent of any other firewall settings (VM will have access to updates proxy, even if policy is set to block all the traffic).
(1) Services tab -\> "qubes-yum-proxy" entry; check qvm-service manual for details
@ -199,12 +208,12 @@ The proxy is running in selected VMs (by default all the NetVMs (1)) and interce
line, or be empty. Note that this file is specifically included from main yum.conf, yum does not support real conf.d configuration style...
Note on treating AppVM's root filesystem non-persistency as a security feature
Note on treating AppVM's root filesystem non-persistence as a security feature
------------------------------------------------------------------------------
As explained above, any AppVM that is based on a Template VM (i.e. which is not a Standalone VM) has its root filesystem non-persistent across the VM reboots. In other words whatever changes the VM makes (or the malware running in this AppVM makes) to its root filesystem, are automatically discarded whenever one restarts the AppVM. This might seem like an excellent anti-malware mechanism to be used inside the AppVM...
However, one should be careful with treating this property as a reliable way to keep the AppVM malware-free. This is because the non-persistency, in the case of normal AppVMs, applies only to the root filesystem and not to the user filesystem (on which the `/home`, `/rw`, and `/usr/local` are stored) for obvious reasons. It is possible that malware, especially malware that could be specifically written to target a Qubes-based AppVMs, could install its hooks inside the user home directory files only. Examples of obvious places for such hooks could be: `.bashrc`, the Firefox profile directory which contains the extensions, or some PDF or DOC documents that are expected to be opened by the user frequently (assuming the malware found an exploitable bug in the PDF or DOC reader), and surely many others places, all in the user's home directory.
However, one should be careful with treating this property as a reliable way to keep the AppVM malware-free. This is because the non-persistence, in the case of normal AppVMs, applies only to the root filesystem and not to the user filesystem (on which the `/home`, `/rw`, and `/usr/local` are stored) for obvious reasons. It is possible that malware, especially malware that could be specifically written to target a Qubes-based AppVMs, could install its hooks inside the user home directory files only. Examples of obvious places for such hooks could be: `.bashrc`, the Firefox profile directory which contains the extensions, or some PDF or DOC documents that are expected to be opened by the user frequently (assuming the malware found an exploitable bug in the PDF or DOC reader), and surely many others places, all in the user's home directory.
One advantage of the non-persistent rootfs though, is that the malware is still inactive before the user's filesystem gets mounted and "processed" by system/applications, which might theoretically allow for some scanning programs (or a skilled user) to reliably scan for signs of infections of the AppVM. But, of course, the problem of finding malware hooks in general is hard, so this would work likely only for some special cases (e.g. an AppVM which doesn't use Firefox, as otherwise it would be hard to scan the Firefox profile directory reliably to find malware hooks there). Also note that the user filesystem's metadata might got maliciously modified by malware in order to exploit a hypothetical bug in the AppVM kernel whenever it mounts the malformed filesystem. However, these exploits will automatically stop working (and so the infection might be cleared automatically) after the hypothetical bug got patched and the update applied (via template update), which is an exceptional feature of Qubes OS.

3
common-tasks/tips-and-tricks.md
View file

@ -58,4 +58,5 @@ Trim for standalone AppVMs
---------------------
The `qvm-trim-template` command is not available for a standalone AppVM.
It is still possible to trim the AppVM disks by using the `fstrim --all` command from the appvm
It is still possible to trim the AppVM disks by using the `fstrim --all` command from the appvm.
You can also add the `discard` option to the mount line in `/etc/fstab` inside the standalone AppVM if you want trimming to be performed automatically, but there may be a performance impact on writes and deletes.

447
common-tasks/usb.md
View file

@ -150,67 +150,32 @@ If you have only a USB mouse connected to a USB qube, but the keyboard is connec
You must do this every time you leave your computer unattended, even if there no risk of anyone else having direct physical access to your computer.
This is because you are guarding the system not only against anyone with local access, but also against possible actions from a potentially compromised USB qube.
If your keyboard is also connected to a USB qube, things are much harder.
Locking the screen (with a traditional password) does not solve the problem, because the USB qube can simply sniff this password and later easily unlock the screen.
One possibility is to set up the screen locker to require an additional step to unlock (i.e., two-factor authentication).
One way to achieve this is to use a [YubiKey], or some other hardware token, or even to manually enter a one-time password.
How to use a USB keyboard
-------------------------
**Caution:** Please carefully read the [Security Warning about USB Input Devices] before proceeding.
In order to use a USB keyboard, you must first attach it to a USB qube, then give that qube permission to pass keyboard input to dom0.
Edit the `qubes.InputKeyboard` policy file in dom0, which is located here:
/etc/qubes-rpc/policy/qubes.InputKeyboard
Add a line like this one to the top of the file:
sys-usb dom0 ask,user=root
(Change `sys-usb` to your desired USB qube.)
You can now use your USB keyboard.
How to use a USB mouse
----------------------
**Caution:** Please carefully read the [Security Warning about USB Input Devices] before proceeding.
In order to use a USB mouse, you must first attach it to a USB qube, then give that qube permission to pass mouse input to dom0.
Edit the `qubes.InputMouse` policy file in dom0, which is located here:
/etc/qubes-rpc/policy/qubes.InputMouse
Add a line like this to the op of the file:
sys-usb dom0 ask,user=root
(Change `sys-usb` to your desired USB qube.)
You can now use your USB mouse.
How to attach USB drives
------------------------
(**Note:** In the present context, the term "USB drive" denotes any
[USB mass storage device][mass-storage]. In addition to smaller flash memory
sticks, this includes things like USB external hard drives.)
Qubes OS supports the ability to attach a USB drive (or just one or more of its
partitions) to any qube easily, no matter which qube actually handles the USB
controller. (The USB controller may be assigned on the **Devices** tab of a
qube's settings page in Qubes VM Manager or by using the
[qvm-pci][Assigning Devices] command. For guidance on finding the correct USB
controller, see [here][usb-controller].)
controller.
USB drive mounting is integrated into the Qubes VM Manager GUI. Simply insert
your USB drive, right-click on the desired qube in the Qubes VM Manager list,
click **Attach/detach block devices**, and select your desired action and
device. This, however, only works for the whole device. If you would like to
attach individual partitions, you must use the command-line tool.
### R4.0 ###
USB drive mounting is integrated into the Devices Widget. This is the tool tray
icon with a yellow square located in the top right of your screen by default.
Simply insert
your USB drive and click on the widget. You will see multiple entries for your
USB drive; typically, `sys-usb:sda`, `sys-usb:sda1`, and `sys-usb:2-1` for example.
The simplest (but slightly less secure, see note below about attaching individual
partitions) option is to attach the entire block drive. In our example, this is `sda`,
so hover over it.
This will pop up a submenu showing running VMs to which the USB drive can be connected.
Click on one and your USB drive will be attached!
Note that attaching individual partitions can be slightly more secure because it doesn't
force the target AppVM to parse the partition table. However, it often means the
AppVM won't detect the new partition and you will need to manually mount it inside
the AppVM. See below for more detailed steps.
The command-line tool you may use to mount whole USB drives or their partitions
is `qvm-block`. This tool can be used to assign a USB drive to a qube as
follows:
@ -220,7 +185,7 @@ follows:
2. In a dom0 console (running as a normal user), list all available block
devices:
qvm-block -l
qvm-block
This will list all available block devices connected to any USB controller
in your system, no matter which qube hosts the controller. The name of the
@ -233,14 +198,14 @@ follows:
usbVM:sdb1 Disk () 2GiB
**Note:** If your device is not listed here, you may refresh the list by
calling (from the qube to which the device is connected):
calling from the qube to which the device is connected (typically `sys-usb`):
sudo udevadm trigger --action=change
3. Assuming your USB drive is attached to dom0 and is `sdb`, we attach the
3. Assuming your USB drive is attached to `sys-usb` and is `sdb`, we attach the
device to a qube with the name `personal` like so:
qvm-block -a personal dom0:sdb
qvm-block attach personal sys-usb:sdb
This will attach the device to the qube as `/dev/xvdi` if that name is not
already taken by another attached device, or `/dev/xvdj`, etc.
@ -248,6 +213,78 @@ follows:
You may also mount one partition at a time by using the same command with
the partition number after `sdb`.
4. The USB drive is now attached to the qube. If using a default qube, you may
open the Nautilus file manager in the qube, and your drive should be
visible in the **Devices** panel on the left. If you've attached a single
partition, you may need to manually mount before it becomes visible:
```
cd ~
mkdir mnt
sudo mount /dev/xvdi mnt
```
5. When you finish using your USB drive, click the eject button or right-click
and select **Unmount**. If you've manually mounted a single partition
in the above step, use:
`sudo umount mnt`
6. In a dom0 console, detach the stick
qvm-block detach <vmname> <device>
7. You may now remove the device.
### R3.2 ###
USB drive mounting is integrated into the Qubes VM Manager GUI. Simply insert
your USB drive, right-click on the desired qube in the Qubes VM Manager list,
click **Attach/detach block devices**, and select your desired action and
device. This, however, only works for the whole device. If you would like to
attach individual partitions, you must use the command-line tool.
Note that attaching individual partitions can be slightly more secure because it doesn't
force the target AppVM to parse the partition table. However, it often means the
AppVM won't detect the new partition and you will need to manually mount it inside
the AppVM. See below for more detailed steps.
The command-line tool you may use to mount whole USB drives or their partitions
is `qvm-block`. This tool can be used to assign a USB drive to a qube as
follows:
1. Insert your USB drive.
2. In a dom0 console (running as a normal user), list all available block
devices:
qvm-block
This will list all available block devices connected to any USB controller
in your system, no matter which qube hosts the controller. The name of the
qube hosting the USB controller is displayed before the colon in the device
name. The string after the colon is the name of the device used within the
qube, like so:
dom0:sdb1 Cruzer () 4GiB
usbVM:sdb1 Disk () 2GiB
**Note:** If your device is not listed here, you may refresh the list by
calling from the qube to which the device is connected (typically `sys-usb`):
sudo udevadm trigger --action=change
3. Assuming your USB drive is attached to `sys-usb` and is `sdb`, we attach the
device to a qube with the name `personal` like so:
qvm-block -a personal sys-usb:sdb
This will attach the device to the qube as `/dev/xvdi` if that name is not
already taken by another attached device, or `/dev/xvdj`, etc.
You may also mount one partition at a time by using the same command with
the partition number after `sdb`. This is slightly more secure because it
does not force the target AppVM to parse the partition table.
**Warning:** when working with single partitions, it is possible to assign
the same partition to multiple qubes. For example, you could attach `sdb1`
to qube1 and then `sdb` to qube2. It is up to the user not to make this
@ -257,10 +294,18 @@ follows:
4. The USB drive is now attached to the qube. If using a default qube, you may
open the Nautilus file manager in the qube, and your drive should be
visible in the **Devices** panel on the left.
visible in the **Devices** panel on the left. If you've attached a single
partition, you may need to manually mount before it becomes visible:
```
cd ~
mkdir mnt
sudo mount /dev/xvdi mnt
```
5. When you finish using your USB drive, click the eject button or right-click
and select **Unmount**.
and select **Unmount**. If you've manually mounted a single partition
in the above step, use:
`sudo umount mnt`
6. In a dom0 console, detach the stick
@ -281,7 +326,7 @@ manually. The device will show up as `/dev/xvdi` (or `/dev/xvdj` if there is
already one device attached -- if two, `/dev/xvdk`, and so on).
### What if I removed the device before detaching it from the VM? ###
### What if I removed the device before detaching it from the VM? (R3.2) ###
Currently (until issue [1082] gets implemented), if you remove the device
before detaching it from the qube, Qubes OS (more precisely, `libvirtd`) will
@ -300,7 +345,7 @@ steps:
[user@dom0 ~]$ qvm-block
sys-usb:sda DataTraveler_2.0 () 246 MiB (attached to 'testvm' as 'xvdi')
[user@dom0 ~]$ xl block-attach testvm phy:/dev/sda backend=sys-usb xvdi
[user@dom0 ~]$ sudo xl block-attach testvm phy:/dev/sda backend=sys-usb xvdi
In above example, all `xl block-attach` parameters can be deduced from the
output of `qvm-block`. In order:
@ -341,7 +386,52 @@ you want to attach the USB device to.
- Fedora: `sudo dnf install qubes-usb-proxy`
- Debian/Ubuntu: `sudo apt-get install qubes-usb-proxy`
### Usage of qubes-usb-proxy ###
### Usage of qubes-usb-proxy (R4.0) ###
This feature is also available from the Devices Widget. This is the tool tray
icon with a yellow square located in the top right of your screen by default.
Simply insert
your USB device and click on the widget. You will see an entry for your device
such as `sys-usb:2-5 - 058f_USB_2.0_Camera` for example.
Hover over it.
This will pop up a submenu showing running VMs to which the USB device can be connected.
Click on one and your device will be attached! You may also use the command line:
Listing available USB devices:
[user@dom0 ~]$ qvm-usb
sys-usb:2-4 04ca:300d 04ca_300d
sys-usb:2-5 058f:3822 058f_USB_2.0_Camera
sys-usb:2-1 03f0:0641 PixArt_HP_X1200_USB_Optical_Mouse
Attaching selected USB device:
[user@dom0 ~]$ qvm-usb attach conferences sys-usb:2-5
[user@dom0 ~]$ qvm-usb
conferences:2-1 058f:3822 058f_USB_2.0_Camera
sys-usb:2-4 04ca:300d 04ca_300d
sys-usb:2-5 058f:3822 058f_USB_2.0_Camera (attached to conferences)
sys-usb:2-1 03f0:0641 PixArt_HP_X1200_USB_Optical_Mouse
Now, you can use your USB device (camera in this case) in the `conferences` qube.
If you see the error `ERROR: qubes-usb-proxy not installed in the VM` instead,
please refer to the [Installation Section][installation].
When you finish, detach the device. This can be done in the GUI by
clicking on the Devices Widget. You will see an entry in bold for your device
such as **`sys-usb:2-5 - 058f_USB_2.0_Camera`**.
Hover over it.
This will pop up a submenu showing running VMs. The one which your device is
connected to will have an Eject button next to it. Click that and your device
will be detached. You may also use the command line:
[user@dom0 ~]$ qvm-usb detach conferences sys-usb:2-5
[user@dom0 ~]$ qvm-usb
sys-usb:2-4 04ca:300d 04ca_300d
sys-usb:2-5 058f:3822 058f_USB_2.0_Camera
sys-usb:2-1 03f0:0641 PixArt_HP_X1200_USB_Optical_Mouse
### Usage of qubes-usb-proxy (R3.2) ###
Listing available USB devices:
@ -371,8 +461,231 @@ When you finish, detach the device:
sys-usb:2-5 058f:3822 058f_USB_2.0_Camera
sys-usb:2-1 03f0:0641 PixArt_HP_X1200_USB_Optical_Mouse
This feature is not yet available in Qubes Manager however, if you would like to contribute to Qubes OS project by implementing it and are a student please consider applying for the [Google Summer of Code][gsoc-page] scholarship and choosing QubesOS Project as a mentor organization. You can find list of our Project Ideas [here][project-page].
This feature is not available in Qubes Manager.
Creating and Using a USB qube
-----------------------------
**Warning:** This has the potential to prevent you from connecting a keyboard to Qubes via USB. There are problems with doing this in an encrypted install (LUKS). If you find yourself in this situation, see this [issue][2270-comm23].
Connecting an untrusted USB device to dom0 is a security risk since dom0,
like almost every OS, reads partition tables automatically. The whole
USB stack is put to work to parse the data presented by the USB device in order
to determine if it is a USB mass storage device, to read its configuration, etc.
This happens even if the drive is then assigned and mounted in another qube.
To avoid this risk, it is possible to prepare and utilize a USB qube.
A USB qube acts as a secure handler for potentially malicious USB devices,
preventing them from coming into contact with dom0 (which could otherwise be
fatal to the security of the whole system). With a USB qube, every time you
connect an untrusted USB drive to a USB port managed by that USB controller, you
will have to attach it to the qube in which you wish to use it (if different
from the USB qube itself), either by using Qubes VM Manager or the command line
(see instructions above). The USB controller may be assigned on the **Devices** tab of a
qube's settings page in Qubes VM Manager or by using the
[qvm-pci][Assigning Devices] command. For guidance on finding the correct USB
controller, see [here][usb-controller].
You can create a USB qube using the management stack by performing the following
as root in dom0:
sudo qubesctl state.sls qvm.sys-usb
Alternatively, you can create a USB qube manually as follows:
1. Read the [Assigning Devices] page to learn how to list and identify your
USB controllers. Carefully check whether you have a USB controller that
would be appropriate to assign to a USB qube. Note that it should have no
input devices, programmable devices, and any other devices that must be
directly available to dom0. If you find a free controller, note its name
and proceed to step 2.
2. Create a new qube. Give it an appropriate name and color label
(recommended: `sys-usb`, red). If you need to attach a networking device,
it might make sense to create a NetVM. If not, an AppVM might make more
sense. (The default `sys-usb` is a NetVM.)
3. In the qube's settings, go to the "Devices" tab. Find the USB controller
that you identified in step 1 in the "Available" list. Move it to the
"Selected" list.
**Caution:** By assigning a USB controller to a USB qube, it will no longer
be available to dom0. This can make your system unusable if, for example,
you have only one USB controller, and you are running Qubes off of a USB
drive.
4. Click "OK." Restart the qube.
5. Recommended: Check the box on the "Basic" tab which says "Start VM
automatically on boot." (This will help to mitigate attacks in which
someone forces your system to reboot, then plugs in a malicious USB
device.)
If the USB qube will not start, see [here][faq-usbvm].
How to hide all USB controllers from dom0
-----------------------------------------
If you create a USB qube manually, there will be a brief period of time during the
boot process during which dom0 will be exposed to your USB controllers (and any
attached devices). This is a potential security risk, since even brief exposure
to a malicious USB device could result in dom0 being compromised. There are two
approaches to this problem:
1. Physically disconnect all USB devices whenever you reboot the host.
2. Hide (i.e., blacklist) all USB controllers from dom0.
**Warning:** If you use a USB [AEM] device, do not use the second option. Using
a USB AEM device requires dom0 to have access to the USB controller to which
your USB AEM device is attached. If dom0 cannot read your USB AEM device, AEM
will hang.
The procedure to hide all USB controllers from dom0 is as follows:
* GRUB2
1. Open the file `/etc/default/grub` in dom0.
2. Find the line that begins with `GRUB_CMDLINE_LINUX`.
3. Add `rd.qubes.hide_all_usb` to that line.
4. Save and close the file.
5. Run the command `grub2-mkconfig -o /boot/grub2/grub.cfg` in dom0.
6. Reboot.
* EFI
1. Open the file `/boot/efi/EFI/qubes/xen.cfg` in dom0.
2. Find the lines that begin with `kernel=`. There may be more than one.
3. Add `rd.qubes.hide_all_usb` to those lines.
4. Save and close the file.
5. Reboot.
(Note: Beginning with R3.2, `rd.qubes.hide_all_usb` is set automatically if you
opt to create a USB qube during installation. This also occurs automatically if
you choose to [create a USB qube] using the `qubesctl` method, which is the
first pair of steps in the linked section.)
**Warning:** A USB keyboard cannot be used to type the disk passphrase
if USB controllers were hidden from dom0. Before hiding USB controllers
make sure your laptop keyboard is not internally connected via USB
(by checking output of `lsusb` command) or that you have a PS/2 keyboard at hand
(if using a desktop PC). Failure to do so will render your system unusable.
Removing a USB qube
-------------------
**Warning:** This procedure will result in your USB controller(s) being attached
directly to dom0.
* GRUB2
1. Shut down the USB qube.
2. In Qubes Manager, right-click on the USB qube and select "Remove VM."
3. Open the file `/etc/default/grub` in dom0.
4. Find the line(s) that begins with `GRUB_CMDLINE_LINUX`.
5. If `rd.qubes.hide_all_usb` appears anywhere in those lines, remove it.
6. Save and close the file.
7. Run the command `grub2-mkconfig -o /boot/grub2/grub.cfg` in dom0.
8. Reboot.
* EFI
1. Shut down the USB qube.
2. In Qubes Manager, right-click on the USB qube and select "Remove VM."
3. Open the file `/boot/efi/EFI/qubes/xen.cfg` in dom0.
4. Find the line(s) that begins with `kernel=`.
5. If `rd.qubes.hide_all_usb` appears anywhere in those lines, remove it.
6. Save and close the file.
7. Reboot.
Security Warning about USB Input Devices
----------------------------------------
**Important security warning. Please read this section carefully!**
If you connect USB input devices (keyboard and mouse) to a VM, that VM will effectively have control over your system.
Because of this, the benefits of using a USB qube are much smaller than using a fully untrusted USB qube.
In addition to having control over your system, such VM can also sniff all the input you enter there (for example, passwords in the case of a USB keyboard).
There is no simple way to protect against sniffing, but you can make it harder to exploit control over input devices.
If you have only a USB mouse connected to a USB qube, but the keyboard is connected directly to dom0 (using a PS/2 connector, for example), you simply need to lock the screen when you are away from your computer.
You must do this every time you leave your computer unattended, even if there no risk of anyone else having direct physical access to your computer.
This is because you are guarding the system not only against anyone with local access, but also against possible actions from a potentially compromised USB qube.
If your keyboard is also connected to a USB qube, things are much harder.
Locking the screen (with a traditional password) does not solve the problem, because the USB qube can simply sniff this password and later easily unlock the screen.
One possibility is to set up the screen locker to require an additional step to unlock (i.e., two-factor authentication).
One way to achieve this is to use a [YubiKey], or some other hardware token, or even to manually enter a one-time password.
How to use a USB keyboard
-------------------------
**Caution:** Please carefully read the [Security Warning about USB Input Devices] before proceeding.
If you use USB keyboard, automatic USB qube creation during installation is disabled.
Additional steps are required to avoid locking you out from the system.
Those steps are not performed by default, because of risk explained in [Security Warning about USB Input Devices].
### R4.0, using salt ###
To allow USB keyboard usage (including early boot for LUKS passphrase), make sure you have the latest `qubes-mgmt-salt-dom0-virtual-machines` package (simply [install dom0 updates][dom0-updates]) and execute in dom0:
sudo qubesctl state.sls qvm.usb-keyboard
The above command will take care of all required configuration, including creating USB qube if not present.
Note that it will expose dom0 to USB devices while entering LUKS passphrase.
Users are advised to physically disconnect other devices from the system for that time, to minimize the risk.
If you wish to perform only subset of this configuration (for example do not enable USB keyboard during boot), see manual instructions below.
### R3.2, manual ###
In order to use a USB keyboard, you must first attach it to a USB qube, then give that qube permission to pass keyboard input to dom0.
Edit the `qubes.InputKeyboard` policy file in dom0, which is located here:
/etc/qubes-rpc/policy/qubes.InputKeyboard
Add a line like this one to the top of the file:
sys-usb dom0 allow,user=root
(Change `sys-usb` to your desired USB qube.)
You can now use your USB keyboard.
For a confirmation dialog each time the USB keyboard is connected, change this line to:
```
sys-usb dom0 ask,default_target=dom0
```
Additionally, if you want to use USB keyboard to enter LUKS passphrase, it is incompatible with [hiding USB controllers from dom0][How to hide all USB controllers from dom0].
You need to revert that procedure (remove `rd.qubes.hide_all_usb` option from files mentioned there) and employ alternative protection during system boot - disconnect other devices during startup.
How to use a USB mouse
----------------------
**Caution:** Please carefully read the [Security Warning about USB Input Devices] before proceeding.
In order to use a USB mouse, you must first attach it to a USB qube, then give that
qube permission to pass mouse input to dom0.
The following steps are already done by default if you created the sys-usb qube with
`qubesctl state.sls qvm.sys-usb` above, or let Qubes create it for you on first boot. However,
if you've created the USB qube manually:
Edit the `qubes.InputMouse` policy file in dom0, which is located here:
/etc/qubes-rpc/policy/qubes.InputMouse
Add a line like this to the top of the file:
sys-usb dom0 allow,user=root
(Change `sys-usb` to your desired USB qube.)
You can now use your USB mouse.
For a confirmation dialog each time the USB mouse is connected, change this line to:
```
sys-usb dom0 ask,default_target=dom0
```
[mass-storage]: https://en.wikipedia.org/wiki/USB_mass_storage_device_class
[Assigning Devices]: /doc/assigning-devices/
@ -383,13 +696,13 @@ This feature is not yet available in Qubes Manager however, if you would like to
[2270-comm23]: https://github.com/QubesOS/qubes-issues/issues/2270#issuecomment-242900312
[1082]: https://github.com/QubesOS/qubes-issues/issues/1082
[hide-usb]: #how-to-hide-all-usb-controllers-from-dom0
[faq-usbvm]: /doc/user-faq/#i-created-a-usbvm-and-assigned-usb-controllers-to-it-now-the-usbvm-wont-boot
[faq-usbvm]: /faq/#i-created-a-usbvm-and-assigned-usb-controllers-to-it-now-the-usbvm-wont-boot
[AEM]: /doc/anti-evil-maid/
[1618]: https://github.com/QubesOS/qubes-issues/issues/1618
[create a USB qube]: #creating-and-using-a-usb-qube
[usb-challenges]: https://blog.invisiblethings.org/2011/05/31/usb-security-challenges.html
[project-page]: /gsoc/
[gsoc-page]: https://summerofcode.withgoogle.com/organizations/6239659689508864/
[YubiKey]: /doc/YubiKey/
[Security Warning about USB Input Devices]: #security-warning-about-usb-input-devices
[How to hide all USB controllers from dom0]: #how-to-hide-all-usb-controllers-from-dom0
[qubes-usb-proxy]: https://github.com/QubesOS/qubes-app-linux-usb-proxy
[dom0-updates]: /doc/software-update-dom0/#how-to-update-software-in-dom0