Re: [PATCH v2] ci: run SELinux kernel test suite

[Ondrej Mosnacek <omosnace@redhat.com>]

Apologies for getting back to this so late... Just some small nitpicks.

On Wed, May 20, 2020 at 6:34 PM <bill.c.roberts@gmail.com> wrote:
> From: William Roberts <william.c.roberts@intel.com>
>
> The current Travis CI runs the userspace tooling and libraries against
> policy files, but cannot test against an SELinux enabled kernel. Thus,
> some tests are not being done in the CI. Travis, unfortunately only
> provides Ubuntu images, so in order to run against a modern distro with
> SELinux in enforcing mode, we need to launch a KVM with something like
> Fedora.
>
> This patch enables this support by launching a Fedora32 Cloud Image with
> the SELinux userspace library passed on from the Travis clone, it then
> builds and replaces the current SELinux bits on the Fedora32 image and
> runs the SELinux testsuite.
>
> Signed-off-by: William Roberts <william.c.roberts@intel.com>
> ---
>  .travis.yml                      |   8 +++
>  scripts/ci/README.md             |   8 +++
>  scripts/ci/fedora-test-runner.sh |  89 ++++++++++++++++++++++++
>  scripts/ci/travis-kvm-setup.sh   | 113 +++++++++++++++++++++++++++++++
>  4 files changed, 218 insertions(+)
>  create mode 100644 scripts/ci/README.md
>  create mode 100755 scripts/ci/fedora-test-runner.sh
>  create mode 100755 scripts/ci/travis-kvm-setup.sh
>
[...]
> diff --git a/scripts/ci/fedora-test-runner.sh b/scripts/ci/fedora-test-runner.sh
> new file mode 100755
> index 000000000000..14bcf5fc469d
> --- /dev/null
> +++ b/scripts/ci/fedora-test-runner.sh
> @@ -0,0 +1,89 @@
> +#!/usr/bin/env bash
> +
> +set -ev
> +
> +# CI Debug output if things go squirrely.
> +getenforce
> +id -Z
> +nproc
> +pwd

I'd add also "uname -r" here to dump the running kernel version (will
probably be also printed later somewhere, but better to have it also
in one place with the other debug info).

> +
> +# Turn off enforcing for the setup to prevent any weirdness from breaking
> +# the CI.
> +setenforce 0
> +
> +dnf clean all -y
> +dnf install -y \
[...]
> diff --git a/scripts/ci/travis-kvm-setup.sh b/scripts/ci/travis-kvm-setup.sh
> new file mode 100755
> index 000000000000..66606e9d4a5b
> --- /dev/null
> +++ b/scripts/ci/travis-kvm-setup.sh
> @@ -0,0 +1,113 @@
> +#!/usr/bin/env bash
> +
> +set -ev
> +
> +TEST_RUNNER="scripts/ci/fedora-test-runner.sh"
> +
> +#
> +# Travis gives us 7.5GB of RAM and two cores:
> +# https://docs.travis-ci.com/user/reference/overview/
> +#
> +MEMORY=4096
> +VCPUS=2

Why not "VCPUS=$(nproc)"?

> +
> +# Install these here so other builds don't have to wait on these deps to download and install
> +sudo apt-get install qemu-kvm libvirt-bin virtinst bridge-utils cpu-checker libguestfs-tools
> +
> +sudo usermod -a -G kvm,libvirt,libvirt-qemu $USER
> +
> +# Verify that KVM is working, useful if Travis every changes anything.

s/every/ever/

> +kvm-ok
> +
> +sudo systemctl enable libvirtd
> +sudo systemctl start libvirtd
> +
> +# Set up a key so we can ssh into the VM
> +ssh-keygen -N "" -f "$HOME/.ssh/id_rsa"
> +
> +#
> +# Get the Fedora Cloud Image, It is a base image that small and ready to go, extract it and modify it with virt-sysprep
> +#  - https://alt.fedoraproject.org/en/verify.html
> +cd $HOME
> +wget https://download.fedoraproject.org/pub/fedora/linux/releases/32/Cloud/x86_64/images/Fedora-Cloud-Base-32-1.6.x86_64.raw.xz

I'd suggest extracting the Fedora release version (32) + the image
version (1.6) into variables, so they can be easily bumped later.

> +
> +# Verify the image
> +curl https://getfedora.org/static/fedora.gpg | gpg --import
> +wget https://getfedora.org/static/checksums/Fedora-Cloud-32-1.6-x86_64-CHECKSUM
> +gpg --verify-files *-CHECKSUM
> +sha256sum --ignore-missing -c *-CHECKSUM
> +
> +# Extract the image
> +unxz -T0 Fedora-Cloud-Base-32-1.6.x86_64.raw.xz
> +
> +# Search is needed for $HOME so virt service can access the image file.
> +chmod a+x $HOME
> +
> +#
> +# Modify the virtual image to:
> +#   - Enable a login, we just use root
> +#   - Enable passwordless login
> +#     - Force a relabel to fix labels on ssh keys
> +#
> +sudo virt-sysprep -a "$HOME/Fedora-Cloud-Base-32-1.6.x86_64.raw" \
> +  --root-password password:123456 \

Do you need to set the password when you use an SSH key to login?

> +  --hostname fedoravm \
> +  --append-line '/etc/ssh/sshd_config:PermitRootLogin yes' \
> +  --append-line '/etc/ssh/sshd_config:PubkeyAuthentication yes' \
> +  --mkdir /root/.ssh \
> +  --upload "$HOME/.ssh/id_rsa.pub:/root/.ssh/authorized_keys" \
> +  --chmod '0600:/root/.ssh/authorized_keys' \
> +  --run-command 'chown root:root /root/.ssh/authorized_keys' \

Could these be replaced with just "--ssh-inject root"?

> +  --copy-in "$TRAVIS_BUILD_DIR:/root" \
> +  --network \
> +  --selinux-relabel
> +
> +#
> +# Now we create a domain by using virt-install. This not only creates the domain, but runs the VM as well
> +# It should be ready to go for ssh, once ssh starts.
> +#
> +sudo virt-install \
> +  --name fedoravm \
> +  --memory $MEMORY \
> +  --vcpus $VCPUS \
> +  --disk "$HOME/Fedora-Cloud-Base-32-1.6.x86_64.raw" \
> +  --import --noautoconsole
> +
> +#
> +# Here comes the tricky part, we have to figure out when the VM comes up AND we need the ip address for ssh. So we
> +# can check the net-dhcp leases, for our host. We have to poll, and we will poll for up 3 minutes in 6 second
> +# intervals, so 30 poll attempts (0-29 inclusive). I don't know of a better way to do this.
> +#
> +# We have a full reboot + relabel, so first sleep gets us close
> +#
> +sleep 30
> +for i in $(seq 0 29); do
> +    echo "loop $i"
> +    sleep 6s
> +    # Get the leases, but tee it so it's easier to debug
> +    sudo virsh net-dhcp-leases default | tee dhcp-leases.txt
> +
> +    # get our ipaddress
> +    ipaddy=$(grep fedoravm dhcp-leases.txt | awk {'print $5'} | cut -d'/' -f 1-1)

Looks cleaner this way:
[...] | awk '{ print $5 }' | cut -d / -f 1)

> +    if [ -n "$ipaddy" ]; then
> +        # found it, we're done looking, print it for debug logs
> +        echo "ipaddy: $ipaddy"
> +        break
> +    fi
> +    # it's empty/not found, loop back and try again.
> +done
> +
> +# Did we find it? If not die.
> +if [ -z "$ipaddy" ]; then
> +    echo "ipaddy zero length, exiting with error 1"
> +    exit 1
> +fi
> +
> +#
> +# Great we have a host running, ssh into it. We specify -o so
> +# we don't get blocked on asking to add the servers key to
> +# our known_hosts.
> +#
> +ssh -tt -o StrictHostKeyChecking=no -o LogLevel=QUIET "root@$ipaddy" "/root/selinux/$TEST_RUNNER"
> +
> +exit 0
> --
> 2.17.1

-- 
Ondrej Mosnacek
Software Engineer, Platform Security - SELinux kernel
Red Hat, Inc.