On Mon, Jan 30, 2017 at 10:35:18PM +0000, Robert Sharp wrote: > Just when I thought I was getting near to switching on strict and all of > a sudden my cron jobs are throwing AVCs all over. > > > The gist of it is all the same, for example: > scontext=user_u:user_r:cronjob_t tcontext=system_u:object_r:crond_tmp_t. > This is from /etc/crontab and has USER=root, so it should be run as a > system crontab and therefore be system_cronjob_t? Here are a couple of > specific AVCs that show this but there are many more similar or > otherwise to do with cron jobs that worked alright until recently:
Yeah, its cuz vixie-cron is dumb. Ive been meaning to fix it but ENOTIME recently. It's related to removing system_u from seusers http://blog.perfinion.com/2016/10/selinux-userspace-26-released/ As a workaround, you can echo "system_u:system_u:s0-s0:c0.c1023" >> /etc/selinux/mcs/seusers you cant use semanage to add it since system_u isnt a valid user, and you'll have to re-add that after loading modules since the file is re-generated. after adding that, restarting vixie-cron will make cronjobs work right again. I will get around to fixing it real-soon-now, sorry about that! -- Jason > > ---- > time->Mon Jan 30 13:00:01 2017 > type=AVC msg=audit(1485781201.744:14756): avc: denied { write open } > for pid=26263 comm="touch" path="/var/spool/cron/lastrun/cron.hourly" > dev="dm-0" ino=787203 scontext=user_u:user_r:cronjob_t > tcontext=user_u:object_r:crond_tmp_t tclass=file permissive=1 > type=AVC msg=audit(1485781201.744:14756): avc: denied { create } for > pid=26263 comm="touch" name="cron.hourly" > scontext=user_u:user_r:cronjob_t tcontext=user_u:object_r:crond_tmp_t > tclass=file permissive=1 > type=AVC msg=audit(1485781201.744:14756): avc: denied { add_name } > for pid=26263 comm="touch" name="cron.hourly" > scontext=user_u:user_r:cronjob_t tcontext=system_u:object_r:crond_tmp_t > tclass=dir permissive=1 > ---- > time->Mon Jan 30 15:40:01 2017 > type=PROCTITLE msg=audit(1485790801.293:14758): > proctitle=2F62696E2F7368002F7573722F7362696E2F72756E2D63726F6E73 > type=PATH msg=audit(1485790801.293:14758): item=0 > name="/var/lock/cron.hourly" inode=5592510 dev=00:11 mode=0120777 ouid=0 > ogid=0 rdev=00:00 obj=user_u:object_r:var_lock_t nametype=NORMAL > type=CWD msg=audit(1485790801.293:14758): cwd="/" > type=SYSCALL msg=audit(1485790801.293:14758): arch=c000003e syscall=6 > success=yes exit=0 a0=1626565d30 a1=3b84123bb70 a2=3b84123bb70 a3=40 > items=1 ppid=26697 pid=26698 auid=4294967295 uid=0 gid=0 euid=0 suid=0 > fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="run-crons" > exe="/bin/bash" subj=user_u:user_r:cronjob_t key=(null) > type=AVC msg=audit(1485790801.293:14758): avc: denied { getattr } for > pid=26698 comm="run-crons" path="/run/lock/cron.hourly" dev="tmpfs" > ino=5592510 scontext=user_u:user_r:cronjob_t > tcontext=user_u:object_r:var_lock_t tclass=lnk_file permissive=1 > > Also, I noticed that the files in /var/spool/cron/lastrun/ have the > following contexts: > > -rw-r--r--. 1 root root user_u:object_r:crond_tmp_t 0 Jan 30 > 03:10 cron.daily > -rw-r--r--. 1 root root user_u:object_r:crond_tmp_t 0 Jan 30 > 15:00 cron.hourly > -rw-r--r--. 1 root root system_u:object_r:system_cronjob_tmp_t 0 Jan 1 > 05:30 cron.monthly > -rw-r--r--. 1 root root user_u:object_r:crond_tmp_t 0 Jan 28 > 04:20 cron.weekly > > the cron.monthly looks like I would expect (system_cronjob_t) but the > rest have been changed since then. > > I have just checked the logs and it confirms that this behaviour started > on 11th Jan, when I updated sec-policy/selinux-base-policy to > 2.20161023-r3. So either something got reset that I need to change, I > haven't restarted something or there is some sort of error in the cron > policy that is causing this? > > Any ideas? > > Thanks - Robert Sharp >
