Merge pull request #384 from yamoyamoto/chore/unset-envs-before-launch-service

feat: Prevent exposure of configuration environment variables to runner workflows

Author: myoung34

README.md

@@ -73,7 +73,7 @@ These containers are built via Github actions that [copy the dockerfile](https:/
 | `NO_DEFAULT_LABELS` | Optional environment variable to disable adding the default self-hosted, platform, and architecture labels to the runner. Any value is considered truthy and will disable them. |
 | `DEBUG_ONLY` | Optional boolean to print debug output but not run any actual registration or runner commands. Used in CI and testing. Default: false |
 | `DEBUG_OUTPUT` | Optional boolean to print additional debug output. Default: false |
-
+| `UNSET_CONFIG_VARS` | Optional flag to unset all configuration environment variables after runner setup but before starting the runner. This prevents these variables from leaking into the workflow environment. Set to 'true' to enable. Defaults to 'false' for backward compatibility. |
 
 ## Tests ##
 

entrypoint.sh

@@ -57,6 +57,8 @@ _RUNNER_GROUP=${RUNNER_GROUP:-Default}
 _GITHUB_HOST=${GITHUB_HOST:="github.com"}
 _RUN_AS_ROOT=${RUN_AS_ROOT:="true"}
 _START_DOCKER_SERVICE=${START_DOCKER_SERVICE:="false"}
+_UNSET_CONFIG_VARS=${UNSET_CONFIG_VARS:="false"}
+_CONFIGURED_ACTIONS_RUNNER_FILES_DIR=${CONFIGURED_ACTIONS_RUNNER_FILES_DIR:-""}
 
 # ensure backwards compatibility
 if [[ -z ${RUNNER_SCOPE} ]]; then
@@ -151,15 +153,42 @@ configure_runner() {
 
 }
 
+unset_config_vars() {
+  echo "Unsetting configuration environment variables"
+  unset RUN_AS_ROOT
+  unset RUNNER_NAME
+  unset RUNNER_NAME_PREFIX
+  unset RANDOM_RUNNER_SUFFIX
+  unset ACCESS_TOKEN
+  unset APP_ID
+  unset APP_PRIVATE_KEY
+  unset APP_LOGIN
+  unset RUNNER_SCOPE
+  unset ORG_NAME
+  unset ENTERPRISE_NAME
+  unset LABELS
+  unset REPO_URL
+  unset RUNNER_TOKEN
+  unset RUNNER_WORKDIR
+  unset RUNNER_GROUP
+  unset GITHUB_HOST
+  unset DISABLE_AUTOMATIC_DEREGISTRATION
+  unset CONFIGURED_ACTIONS_RUNNER_FILES_DIR
+  unset EPHEMERAL
+  unset DISABLE_AUTO_UPDATE
+  unset START_DOCKER_SERVICE
+  unset NO_DEFAULT_LABELS
+  unset UNSET_CONFIG_VARS
+}
 
 # Opt into runner reusage because a value was given
-if [[ -n "${CONFIGURED_ACTIONS_RUNNER_FILES_DIR}" ]]; then
+if [[ -n "${_CONFIGURED_ACTIONS_RUNNER_FILES_DIR}" ]]; then
   echo "Runner reusage is enabled"
 
   # directory exists, copy the data
-  if [[ -d "${CONFIGURED_ACTIONS_RUNNER_FILES_DIR}" ]]; then
+  if [[ -d "${_CONFIGURED_ACTIONS_RUNNER_FILES_DIR}" ]]; then
     echo "Copying previous data"
-    cp -p -r "${CONFIGURED_ACTIONS_RUNNER_FILES_DIR}/." "/actions-runner"
+    cp -p -r "${_CONFIGURED_ACTIONS_RUNNER_FILES_DIR}/." "/actions-runner"
   fi
 
   if [ -f "/actions-runner/.runner" ]; then
@@ -177,10 +206,10 @@ else
   fi
 fi
 
-if [[ -n "${CONFIGURED_ACTIONS_RUNNER_FILES_DIR}" ]]; then
-  echo "Reusage is enabled. Storing data to ${CONFIGURED_ACTIONS_RUNNER_FILES_DIR}"
+if [[ -n "${_CONFIGURED_ACTIONS_RUNNER_FILES_DIR}" ]]; then
+  echo "Reusage is enabled. Storing data to ${_CONFIGURED_ACTIONS_RUNNER_FILES_DIR}"
   # Quoting (even with double-quotes) the regexp brokes the copying
-  cp -p -r "/actions-runner/_diag" "/actions-runner/svc.sh" /actions-runner/.[^.]* "${CONFIGURED_ACTIONS_RUNNER_FILES_DIR}"
+  cp -p -r "/actions-runner/_diag" "/actions-runner/svc.sh" /actions-runner/.[^.]* "${_CONFIGURED_ACTIONS_RUNNER_FILES_DIR}"
 fi
 
 
@@ -204,6 +233,11 @@ if [[ ${_START_DOCKER_SERVICE} == "true" ]]; then
   fi
 fi
 
+# Unset configuration environment variables if the flag is set
+if [[ ${_UNSET_CONFIG_VARS} == "true" ]]; then
+  unset_config_vars
+fi
+
 # Container's command (CMD) execution as runner user
 
 
@@ -235,7 +269,7 @@ if [[ ${_RUN_AS_ROOT} == "true" ]]; then
   fi
 else
   if [[ $(id -u) -eq 0 ]]; then
-    [[ -n "${CONFIGURED_ACTIONS_RUNNER_FILES_DIR}" ]] && chown -R runner "${CONFIGURED_ACTIONS_RUNNER_FILES_DIR}"
+    [[ -n "${_CONFIGURED_ACTIONS_RUNNER_FILES_DIR}" ]] && chown -R runner "${_CONFIGURED_ACTIONS_RUNNER_FILES_DIR}"
     chown -R runner "${_RUNNER_WORKDIR}" /actions-runner
     # The toolcache is not recursively chowned to avoid recursing over prepulated tooling in derived docker images
     chown runner /opt/hostedtoolcache/