qubes-test-mirage

These scripts can be used to test Mirage unikernels on Qubes. They provide a secure way to transfer the image to dom0 and run it. Hopefully.

First, use qubes-manager to create a new AppVM called mirage-test. You can make it standalone or not and use any template (it doesn't matter because unikernels already contain all their code and don't need to use a disk to boot).

Next, still in dom0, create a new mirage-test kernel, with an empty modules.img and vmlinuz and a compressed empty file for the initramfs, and then set that as the kernel for the new VM:

# mkdir /var/lib/qubes/vm-kernels/mirage-test
# cd /var/lib/qubes/vm-kernels/mirage-test
# touch modules.img
# touch vmlinuz
# cat /dev/null | gzip > initramfs
# touch test-mirage-ok
# qvm-prefs -s mirage-test kernel mirage-test

Only kernels with a test-mirage-ok file can be updated using this program.

Build the test-mirage binaries:

$ make

The default make target uses Docker to build statically-linking binaries, which ensures they will work with the version of Fedora in dom0. You can also use make local to build without Docker, but you'll need to use a compatible version of glibc in that case.

This will generate two binaries in the _build/default directory:

• dom0.exe will run in dom0 and accepts kernel uploads.
• dev.exe will run in your dev VM and sends kernel images to dom0.

Copy dom0.exe to dom0 as /usr/local/bin/test-mirage-dom0 (and make it executable). The easiest way to do this is to run these commands in dom0 (dev is the name of the build VM and you'll need to adjust the path):

# qvm-run -p dev 'cat /path/to/test-mirage/_build/default/dom0.exe' > dom0.exe
# mv dom0.exe /usr/local/bin/test-mirage-dom0
# chmod a+x /usr/local/bin/test-mirage-dom0

Create /etc/qubes-rpc/talex5.TestMirage containing just that path:

# echo /usr/local/bin/test-mirage-dom0 > /etc/qubes-rpc/talex5.TestMirage

Create a policy allowing your dev VM to use the service, as /etc/qubes-rpc/policy/talex5.TestMirage:

# cat > /etc/qubes-rpc/policy/talex5.TestMirage << EOF
dev dom0 allow
\$anyvm	\$anyvm	deny
EOF

The policy says that dev (your dev VM) can use the talex5.TestMirage service in dom0.

Then you can test any Mirage image with the test-mirage script, e.g.

$ /path/to/test-mirage/test-mirage mir-console.xen mirage-test
Waiting for 'Ready'... OK
Uploading 'mir-console.xen' (4184144 bytes) to "mirage-test"
Waiting for 'Booting'... OK
ERROR: VM already stopped!
--> Creating volatile image: /var/lib/qubes/appvms/mirage-test/volatile.img...
--> Loading the VM (type = AppVM)...
--> Starting Qubes DB...
--> Setting Qubes DB info for the VM...
--> Updating firewall rules...
--> Starting the VM...
MirageOS booting...
Initialising timer interface
Initialising console ... done.
hello
world
...

Note: the ERROR: VM already stopped! line is because it tries to stop any existing VM first, and this gets printed if it isn't already running.

Once started, the test VM console is attached using sudo xl console -c, with stdin and stdout connected to the process in your dev VM. I am assuming that this command does not provide a way to escape from the VM by entering some special character sequence (the usual Ctrl-] does not work since this is not a tty, and would just end the process in any case).

Note: Your unikernel should implement the qrexec protocol so that Qubes can control it with qvm-run. See qubes-mirage-skeleton for an example unikernel that does this. Alternatively, you can configure with mirage configure -t qubes to have this set up automatically.

LICENSE

Copyright (c) 2015, Thomas Leonard All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

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