Kushal Das

FOSS and life. Kushal Das talks here.

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Running SecureDrop inside of podman containers on Fedora 33

Last week, while setting up a Fedora 33 system, I thought of running the SecureDrop development container there, but using podman instead of the Docker setup we have.

I tried to make minimal changes to our existing scripts. Added a ~/bin/docker file, with podman $@ inside (and the sha-bang line).

Next, I provided the proper label for SELinux:

sudo chcon -Rt container_file_t securedrop

The SecureDrop container runs as the normal user inside of the Docker container. I can not do the same here as the filesystem gets mounted as root, and I can not write in it. So, had to modify one line in the bash script, and also disabled another function call which deletes the /dev/random file inside of the container.

diff --git a/securedrop/bin/dev-shell b/securedrop/bin/dev-shell
index ef424bc01..37215b551 100755
--- a/securedrop/bin/dev-shell
+++ b/securedrop/bin/dev-shell
@@ -72,7 +72,7 @@ function docker_run() {
            -e LANG=C.UTF-8 \
            -e PAGE_LAYOUT_LOCALES \
            -e PATH \
-           --user "${USER:-root}" \
+           --user root \
            --volume "${TOPLEVEL}:${TOPLEVEL}" \
            --workdir "${TOPLEVEL}/securedrop" \
            --name "${SD_CONTAINER}" \
diff --git a/securedrop/bin/run b/securedrop/bin/run
index e82cc6320..0c11aa8db 100755
--- a/securedrop/bin/run
+++ b/securedrop/bin/run
@@ -9,7 +9,7 @@ cd "${REPOROOT}/securedrop"
 source "${BASH_SOURCE%/*}/dev-deps"
 
 run_redis &
-urandom
+#urandom
 run_sass --watch &
 maybe_create_config_py
 reset_demo

This time I felt that build time for verifying each cached layer is much longer than what it used to be for podman. Maybe I am just mistaken. The SecureDrop web application is working very fine inside.

Package build containers

We also use containers to build Debian packages. And those molecule scenarios were failing as ansible.posix.synchronize module could not sync to a podman container. I asked if there is anyway to do that, and by the time I woke up, Adam Miller had a branch that fixed the issue. I directly used the same in my virtual environment. The package build was successful. Then, the testinfra tests failed due as it could not create the temporary directory inside of the container. I already opened an issue for the same.

Podman on Debian Buster

I use podman on all of my production servers, and also inside of the Qubes system in Fedora VMs. A few days ago I saw this post and thought of trying out the steps on my Debian Buster system.

But, it seems it requires one more installation step, so I am adding the updated installation steps for Debian Buster here.

Install all build dependencies

sudo apt -y install \
  gcc \
  make \
  cmake \
  git \
  btrfs-progs \
  golang-go \
  go-md2man \
  iptables \
  libassuan-dev \
  libc6-dev \
  libdevmapper-dev \
  libglib2.0-dev \
  libgpgme-dev \
  libgpg-error-dev \
  libostree-dev \
  libprotobuf-dev \
  libprotobuf-c-dev \
  libseccomp-dev \
  libselinux1-dev \
  libsystemd-dev \
  pkg-config \
  runc \
  uidmap \
  libapparmor-dev \
  libglib2.0-dev \
  libcap-dev \
  libseccomp-dev

Install latest Golang

Download and install latest golang and also make sure that you have a proper $GOPATH variable. You can read more here.

Install conmon

conmon is the OCI container runtime monitor. Install it via the following steps:

git clone https://github.com/containers/conmon
cd conmon
make
sudo make podman
sudo cp /usr/local/libexec/podman/conmon  /usr/local/bin/

Install CNI plugins

git clone https://github.com/containernetworking/plugins.git $GOPATH/src/github.com/containernetworking/plugins
cd $GOPATH/src/github.com/containernetworking/plugins
./build_linux.sh
sudo mkdir -p /usr/libexec/cni
sudo cp bin/* /usr/libexec/cni

Setup the bridge

sudo mkdir -p /etc/cni/net.d
curl -qsSL https://raw.githubusercontent.com/containers/libpod/master/cni/87-podman-bridge.conflist | sudo tee /etc/cni/net.d/99-loopback.conf

Create the configuration files

Next, we need configuration files for the registries and also the policy file.

sudo mkdir -p /etc/containers
sudo curl https://raw.githubusercontent.com/projectatomic/registries/master/registries.fedora -o /etc/containers/registries.conf
sudo curl https://raw.githubusercontent.com/containers/skopeo/master/default-policy.json -o /etc/containers/policy.json

Installing slirp4netns

slirp4netns is used for user-mode networking for unprivileged network namespaces. At the time of the writing this blog post, the latest release is 0.4.2.

git clone https://github.com/rootless-containers/slirp4netns
cd slirp4netns
./autogen.sh
./configure --prefix=/usr
make
sudo make install

Installing podman

Finally we are going to install podman.

git clone https://github.com/containers/libpod/ $GOPATH/src/github.com/containers/libpod
cd $GOPATH/src/github.com/containers/libpod
make
sudo make install

Testing podman

Now you can test podman on your Debian system.

podman pull fedora:latest
podman run -it --rm /usr/bin/bash fedora:latest

Using podman for containers

Podman is one of the newer tool in the container world, it can help you to run OCI containers in pods. It uses Buildah to build containers, and runc or any other OCI compliant runtime. Podman is being actively developed.

I have moved the two major bots we use for dgplug summer training (named batul and tenida) under podman and they are running well for the last few days.

Installation

I am using a Fedora 28 system, installation of podman is as simple as any other standard Fedora package.

$ sudo dnf install podman

While I was trying out podman, I found it was working perfectly in my DigitalOcean instance, but, not so much on the production vm. I was not being able to attach to the stdout.

When I tried to get help in #podman IRC channel, many responded, but none of the suggestions helped. Later, I gave access to the box to Matthew Heon, one of the developer of the tool. He identified the Indian timezone (+5:30) was too large for the timestamp buffer and thus causing this trouble.

The fix was pushed fast, and a Fedora build was also pushed to the testing repo.

Usage

To learn about different available commands, visit this page.

First step was to build the container images, it was as simple as:

$ sudo podman build -t kdas/imagename .

I reused my old Dockerfiles for the same. After this, it was just simple run commands to start the containers.