How to change removable devices default mount permission on Red Hat Enterprise Linux 5.

Solution Verified - Updated -

Environment

Red Hat Enterprise Linux 5

Issue

  • How to change default mount permission of CDROM.
  • How to change default mount permission of USB Drive.
  • Changing /dev/ permission using chmod will persist upon reboot?

Resolution

Changing /dev/(usb,cdrom,dvd) permissions using chmod will not persist over reboot. because all system device nodes in the  dev  directory are managed by the udev program and permissions in udev are a bit misleading.

For removable devices (and other security sensitive devices), the OS sets the permissions  based on the console security settings.

Console security settings can be modified by editing following file.

/etc/security/console.perms.d/50-default.perm

For example :

To change CDROM(sr0) default mount permission from 0600(rw------) to 0660 (rw-rw----), Modify following entry in 50-default-perms.

From

<console>  0600 <cdrom>      0660 root,disk</code>

To

<console>  0660 <cdrom>      0660 root.disk

Similarly, other removable devices. e.g Floppy,DVD,USB Drive,Camera default mount permissions can be changed by editing above file.

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