Magento changes file permission of cron.sh after backup -

Magento changes file permission of cron.sh after backup -

if backup magento changes file permission of cron.sh 644 , cron daemon sends me error message "/bin/sh: /magento/cron.sh: permission denied". error right because user doing cronjob hasn't permission execute. work if permission @ to the lowest degree 744.

is there possibility set file permission automatically correct? in future backup part of cronjob , take place in night need prepare issue.

magento permissions cron backup