Red Hat Bugzilla – Bug 988519
cron jobs fail due to selinux context mismatch
Last modified: 2016-11-07 22:47:14 EST
Description of problem: Commands which call "oo_spawn" (e.g., "gear" or "ctl_app" commands) do not work inside cron jobs. The reason is that the "user" part of selinux context is expected to be "unconfined_u", but under cron it is "system_u" Steps to Reproduce: 1. create an app which has the "cron" cartridge installed 2. add a script called .openshift/cron/minutely/restart.sh to your git repo with these contents: #!/bin/sh gear stop gear start Actual results: The script will fail with a "could not open session" error Expected results: The script should succeed Additional info: I tracked this down to the oo_spawn function in node/lib/openshift-origin-node/utils/shell_exec.rb The code runs: current_context = SELinux.getcon target_context = SELinux.context_from_defaults(SELinux.get_mcs_label(options[:uid])) and compares the two. if they do not match, then it tries to spawn the specified command under runuser / runcon; with our PAM configuration, this is only allowed for root. When a command fails in this way under cron, you'll see messages like this in /var/log/secure: Jul 25 14:35:16 ex-std-nodeXX runuser: pam_unix(runuser:session): session opened for user XXXXXXXXX by (uid=XXXX) Jul 25 14:35:16 ex-std-nodeXX runuser: pam_namespace(runuser:session): Error opening config file /etc/security/namespace.d/shm.conf Jul 25 14:35:16 ex-std-nodeXX runuser: PAM audit_open() failed: Permission denied Jul 25 14:35:16 ex-std-nodeXX runuser: pam_unix(runuser:session): session closed for user XXXXXXXXX
I don't know whether it's the _correct_ fix, but one possible fix would be to change the runcon invocation in daemon_as_user in oo-scheduled-jobs. It currently has: daemon --user="$uuid" runcon -r system_r -t openshift_t -l $mcs_level "$@" which could be: daemon --user="$uuid" runcon -u unconfined_u -r system_r -t openshift_t -l $mcs_level "$@"
Implemented the above fix: https://github.com/openshift/origin-server/pull/3173 Stopping gear... CLIENT_RESULT: Stopping CRON cart Waiting for stop to finish Starting gear... App container start_gear CLIENT_RESULT: Starting CRON cart __________________________________________________________________________ Thu Jul 25 16:40:11 EDT 2013: END minutely cron run - status=0 __________________________________________________________________________
Commit pushed to master at https://github.com/openshift/origin-server https://github.com/openshift/origin-server/commit/d1f0ecc25c07ef8c1c9aaabc616b3e4353bedd22 Bug 988519 - Ensure that the gear task runs as unconfined_u.
It's fixed, verified on devenv_3572, please refer to the following results: 1. create an app which has the "cron" cartridge installed 2. add a script called .openshift/cron/minutely/restart.sh to your git repo with these contents and git push: #!/bin/sh gear stop gear start 3. ssh into this app and check the cron log \> cat ./cron/log/cron.minutely.log Stopping gear... CLIENT_RESULT: Stopping CRON cart Waiting for stop to finish Starting gear... CLIENT_RESULT: Starting CRON cart __________________________________________________________________________ Mon Jul 29 01:40:14 EDT 2013: END minutely cron run - status=0 __________________________________________________________________________