cron job executing script not writing to file

Question

I have a server running AIDE, and a cron job that runs executes a bash script and sends an email alert out. It is still a WIP, but I can't get the script to run properly. When the script is executed, my output file defined here /sbin/aide --check > /tmp/$AIDEOUT is still an empty file. I even tried a simple /bin/echo "hello world" > /tmp/$AIDEOUT and it also doesn't seem to work. The /tmp/$AIDEOUT file remains empty.

However, if I run this script manually without using Cron, it runs fine.

Here is my bash script

#!/bin/bash

PATH=/sbin:/bin:/usr/sbin:/usr/bin

MYDATE=`date +%Y-%m-%d`
AIDEOUT="AIDE-${MYDATE}.txt"
MAIL_TO=
ALLMATCH='All files match AIDE database. Looks okay!'
MAIL_FROM=

/bin/touch /tmp/$AIDEOUT
/bin/chmod 755 /tmp/$AIDEOUT
#/bin/echo "Aide check `date`" > /tmp/$AIDEOUT
/sbin/aide --check > /tmp/$AIDEOUT

if ! grep -q "$ALLMATCH" /tmp/$AIDEOUT; then
    /usr/bin/mailx -s "Daily AIDE report for $(hostname)-${ENVIRONMENT_NAME} ${AWS_REGION}" -r $MAILFROM $MAILTO  < /tmp/$AIDEOUT
fi

#/bin/rm /tmp/$AIDEOUT

/sbin/aide --update
/usr/bin/mv /var/lib/aide/aide.db.gz /var/lib/aide/db_backup/aide.db.gz-$(date +"%m-%d-%y")
/usr/bin/mv /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz

my cronjob is defined in /etc/cron.d/aide */5 * * * * root /usr/local/etc/cron_aide2.sh

Thanks!

Answer 1

You are using selinux. If you "setenforce 0" and then let cron run, you will get the output you expect. At the root shell, your selinux context is:

unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023

But when running from Cron, your selinux context starts as:

system_u:system_r:system_cronjob_t:s0-s0:c0.c1023

The solution is downright silly. Instead of:

/sbin/aide --check > /tmp/$AIDEOUT

use

/sbin/aide --check 2>&1 | cat > /tmp/$AIDEOUT

Answer 2

Probably aide output to stderr but not to stdout. Try redirect stderr

/sbin/aide --check 2> /tmp/$AIDEOUT

Or both stdout and stderr

/sbin/aide --check 2>&1 /tmp/$AIDEOUT

https://stackoverflow.com/a/637834/205355

Answer 3

I would verify that your cron is actually running. You can look in /var/log/cron and see if there is an entry for that. If not, then possibly verify that the file is executable. If selinux is enabled, you might check in the audit logs.