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Just when I thought I was getting near to switching on strict and all of |
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a sudden my cron jobs are throwing AVCs all over. |
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The gist of it is all the same, for example: |
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scontext=user_u:user_r:cronjob_t tcontext=system_u:object_r:crond_tmp_t. |
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This is from /etc/crontab and has USER=root, so it should be run as a |
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system crontab and therefore be system_cronjob_t? Here are a couple of |
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specific AVCs that show this but there are many more similar or |
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otherwise to do with cron jobs that worked alright until recently: |
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---- |
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time->Mon Jan 30 13:00:01 2017 |
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type=AVC msg=audit(1485781201.744:14756): avc: denied { write open } |
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for pid=26263 comm="touch" path="/var/spool/cron/lastrun/cron.hourly" |
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dev="dm-0" ino=787203 scontext=user_u:user_r:cronjob_t |
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tcontext=user_u:object_r:crond_tmp_t tclass=file permissive=1 |
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type=AVC msg=audit(1485781201.744:14756): avc: denied { create } for |
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pid=26263 comm="touch" name="cron.hourly" |
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scontext=user_u:user_r:cronjob_t tcontext=user_u:object_r:crond_tmp_t |
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tclass=file permissive=1 |
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type=AVC msg=audit(1485781201.744:14756): avc: denied { add_name } |
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for pid=26263 comm="touch" name="cron.hourly" |
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scontext=user_u:user_r:cronjob_t tcontext=system_u:object_r:crond_tmp_t |
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tclass=dir permissive=1 |
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---- |
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time->Mon Jan 30 15:40:01 2017 |
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type=PROCTITLE msg=audit(1485790801.293:14758): |
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proctitle=2F62696E2F7368002F7573722F7362696E2F72756E2D63726F6E73 |
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type=PATH msg=audit(1485790801.293:14758): item=0 |
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name="/var/lock/cron.hourly" inode=5592510 dev=00:11 mode=0120777 ouid=0 |
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ogid=0 rdev=00:00 obj=user_u:object_r:var_lock_t nametype=NORMAL |
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type=CWD msg=audit(1485790801.293:14758): cwd="/" |
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type=SYSCALL msg=audit(1485790801.293:14758): arch=c000003e syscall=6 |
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success=yes exit=0 a0=1626565d30 a1=3b84123bb70 a2=3b84123bb70 a3=40 |
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items=1 ppid=26697 pid=26698 auid=4294967295 uid=0 gid=0 euid=0 suid=0 |
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fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="run-crons" |
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exe="/bin/bash" subj=user_u:user_r:cronjob_t key=(null) |
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type=AVC msg=audit(1485790801.293:14758): avc: denied { getattr } for |
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pid=26698 comm="run-crons" path="/run/lock/cron.hourly" dev="tmpfs" |
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ino=5592510 scontext=user_u:user_r:cronjob_t |
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tcontext=user_u:object_r:var_lock_t tclass=lnk_file permissive=1 |
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Also, I noticed that the files in /var/spool/cron/lastrun/ have the |
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following contexts: |
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-rw-r--r--. 1 root root user_u:object_r:crond_tmp_t 0 Jan 30 |
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03:10 cron.daily |
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-rw-r--r--. 1 root root user_u:object_r:crond_tmp_t 0 Jan 30 |
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15:00 cron.hourly |
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-rw-r--r--. 1 root root system_u:object_r:system_cronjob_tmp_t 0 Jan 1 |
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05:30 cron.monthly |
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-rw-r--r--. 1 root root user_u:object_r:crond_tmp_t 0 Jan 28 |
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04:20 cron.weekly |
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the cron.monthly looks like I would expect (system_cronjob_t) but the |
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rest have been changed since then. |
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I have just checked the logs and it confirms that this behaviour started |
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on 11th Jan, when I updated sec-policy/selinux-base-policy to |
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2.20161023-r3. So either something got reset that I need to change, I |
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haven't restarted something or there is some sort of error in the cron |
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policy that is causing this? |
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Any ideas? |
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Thanks - Robert Sharp |
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