Backing up permissions on Linux
Solution 1:
To back up all permissions on the system:
getfacl -R / > acl_backup
To restore:
setfacl --restore=acl_backup
Of course, check out the manpages but it's a pretty straight forward command that many people are unaware of:
man getfacl
man setfacl
Solution 2:
You can run ls -lR / > permissions_backup to create a file containing all permissions, but this would be quite hard to restore. You could of course quickly write a script to do it.