diff --git a/Dockerfile b/Dockerfile index 91282d779..17d2499dd 100644 --- a/Dockerfile +++ b/Dockerfile @@ -54,6 +54,10 @@ RUN for dir in \ WORKDIR /runner +# NB: this appears to be necessary for container builds based on this container, since we can't rely on the entrypoint +# script to run during a build to fix up /etc/passwd. This envvar value, and the fact that all user homedirs are +# set to /home/runner is an implementation detail that may change with future versions of runner and should not be +# assumed by other code or tools. ENV HOME=/home/runner ADD utils/entrypoint.sh /bin/entrypoint diff --git a/utils/entrypoint.sh b/utils/entrypoint.sh index b28be9cf8..1bb01d34d 100755 --- a/utils/entrypoint.sh +++ b/utils/entrypoint.sh @@ -1,27 +1,60 @@ #!/usr/bin/env bash -# In OpenShift, containers are run as a random high number uid -# that doesn't exist in /etc/passwd, but Ansible module utils -# require a named user. So if we're in OpenShift, we need to make -# one before Ansible runs. -if [[ (`id -u` -ge 500 || -z "${CURRENT_UID}") ]]; then - - # Only needed for RHEL 8. Try deleting this conditional (not the code) - # sometime in the future. Seems to be fixed on Fedora 32 - # If we are running in rootless podman, this file cannot be overwritten - ROOTLESS_MODE=$(cat /proc/self/uid_map | head -n1 | awk '{ print $2; }') - if [[ "$ROOTLESS_MODE" -eq "0" ]]; then -cat << EOF > /etc/passwd -root:x:0:0:root:/root:/bin/bash -runner:x:`id -u`:`id -g`:,,,:/home/runner:/bin/bash -EOF - fi +# We need to fix a number of problems here that manifest under different container runtimes, as well as tweak some +# things to simplify runner's containerized launch behavior. Since runner currently always expects to bind-mount its +# callback plugins under ~/.ansible, it must have prior knowledge of the user's homedir before the container is launched +# in order to know where to mount in the callback dir. In all cases, we must get a consistent answer from $HOME +# and anything that queries /etc/passwd for a homedir (eg, `~root`), or lots of things (including parts of Ansible +# core itself) will be broken. + +# If we're running as a legit default user that has an entry in /etc/passwd and a valid homedir, we're all good. + +# If the username/uid we're running under is not represented in /etc/passwd or the current user's homedir is something +# other than /home/runner (eg, the container was run with --user and some dynamic unmapped UID from the host with +# primary GID 0), we need to correct that in order for ansible-runner's callbacks to function properly. Some things +# (eg podman/cri-o today) already create an /etc/passwd entry on the fly in this case, but they set the homedir to +# WORKDIR, which causes potential collisions with mounted/mapped volumes. For consistency, we'll +# just always set the current user's homedir to `/home/runner`, which we've already configured in a way +# that should always work with known container runtimes (eg, ug+rwx and all dirs owned by the root group). + +# If current user is not listed in /etc/passwd, add an entry with username==uid, primary gid 0, and homedir /home/runner + +# If current user is in /etc/passwd but $HOME != `/home/runner`, rewrite that user's homedir in /etc/passwd to +# /home/runner and export HOME=/home/runner for this session only. All new sessions (eg podman exec) should +# automatically set HOME to the value in /etc/passwd going forward. + +# Ideally in the future, we can come up with a better way for the outer runner to dynamically inject its callbacks, or +# rely on the inner runner's copy. This would allow us to restore the typical POSIX user homedir conventions. + +# if any of this business fails, we probably want to fail fast +if [ -n "$EP_DEBUG" ]; then + set -eux + echo 'hello from entrypoint' +else + set -e +fi + +# current user might not exist in /etc/passwd at all +if ! $(whoami &> /dev/null) || ! getent passwd $(whoami || id -u) &> /dev/null ; then + if [ -n "$EP_DEBUG" ]; then + echo "adding missing uid $(id -u) into /etc/passwd" + fi + echo "$(id -u):x:$(id -u):0:container user $(id -u):/home/runner:/bin/bash" >> /etc/passwd + export HOME=/home/runner +fi -cat < /etc/group -root:x:0:runner -runner:x:`id -g`: -EOF +MYHOME=`getent passwd $(whoami) | cut -d: -f6` +if [ "$MYHOME" != "$HOME" ] || [ "$MYHOME" != "/home/runner" ]; then + if [ -n "$EP_DEBUG" ]; then + echo "replacing homedir for user $(whoami)" + fi + # sed -i wants to create a tempfile next to the original, which won't work with /etc permissions in many cases, + # so just do it in memory and overwrite the existing file if we succeeded + NEWPW=$(sed -r "s/(^$(whoami):(.*:){4})(.*:)/\1\/home\/runner:/g" /etc/passwd) + echo "$NEWPW" > /etc/passwd + # ensure the envvar matches what we just set in /etc/passwd for this session; future sessions set automatically + export HOME=/home/runner fi if [[ -n "${LAUNCHED_BY_RUNNER}" ]]; then