FatMin

Finding / Eliminating rogue NFS mounts in Mac OS X

There is a handy utility called Directory Utility which allows you to configure connections to directory servers.  It also contains information for persistent NFS mounts across reboots.  If you ever wondered where these phantom mounts came from or you are trying to eliminate a mount that no longer exists go to /System/Library/CoreServices/Directory Utility.

From within Directory utility, click on Directory Editor and then select Mounts from the Viewing categories.  There you will find all mounts and add/remove as required.

 

RHEL6 - More on Cryptsetup and Luks -- Removing Encryption

Way back in the day -- back in March of two thousand-naught-eleven, I added a blog post on how to encrypt a partion using crypsetup and luks on RHEL. Its title, ironically enought was, RHEL, How to Encrypt a Partition Using Cryptsetup and Luks.

Today we are going to talk about how to revert an encyrpted partion back to its unencrypted state so that i can use my usb drive normally again.

# cryptsetup status freeagent
/dev/mapper/freeagent is active.
  type:    LUKS1
  cipher:  aes-cbc-essiv:sha256
  keysize: 256 bits
  device:  /dev/sdd1
  offset:  4096 sectors
  size:    2930267906 sectors
  mode:    read/write

First take note of the device name and the name the dev mapper has given the device. The former is /dev/sdd1 and the latter is /dev/mapper/freeagent.

So first lets remove the key file mapping. You will be prompted for your LUKS passphrase

#cryptsetup luksRemoveKey /dev/sdd1
Enter LUKS passphrase to be deleted:

Then lets remove the dev/mapper mapping for /dev/sdd1. Once complete we are free to create a new filesystem on the disk as needed.

#cryptsetup remove /dev/mapper/freeagent /dev/sdd1

 

Disk Encryption: High-impact Strategies - What You Need to Know: Definitions, Adoptions, Impact, Benefits, Maturity, Vendors

RHEL - How to Encrypt a Partition using Cryptsetup and LUKS

Cryptsetup uses dm-crypt to encrypt a disk at the partition level.  In RHEL, cryptsetup is used with Linux Unified Key Setup (LUKS), a disk encryption specification. Mounting a LUKS encrypted partiton requires a passphrase, which can either be passed in a file or via the command line. Read more about dm-crypt here.

Anyway to use crypsetup, you first must have a free partiton on a disk. In this instance I am using /dev/sdc1, which is a freeagent external usb drive.

First initialize the LUKS partition. My target is /dev/sdc1

#cryptsetup luksFormat /dev/sdc1

Then open the LUKS partition setup the dev mapper device. The command below creates /dev/mapper/freeagent

#cryptsetup luksOpen /dev/sdc1 freeagent

Create a passkey file if you want the device to be able to automount at boot. 

#vi /root/freeagent_passkey && chmod 600 /root/freeagent_passkey

Make cryptsetup aware of the key

#cryptsetup luksAddKey /dev/sdc1 /root/freeagent_passkey

Dont forget to make a filesystem

#mkfs -t ext4 /dev/mapper/freeagent

Then add the following to /etc/fstab...

/dev/mapper/freeagent   /freeagent              ext4    _netdev         1 1

And add the following to /etc/crypttab. Note that the first entry is the name of the /dev/mapper device

freeagent       /dev/sdc1       /freeagent

To get a status on a device and to see the mappings between /dev/mapper and /dev/sdc1

#cryptsetup status

/dev/mapper/freeagent
/dev/mapper//dev/mapper/freeagent is active:
  cipher:  aes-cbc-essiv:sha256
  keysize: 128 bits
  device:  /dev/sdc1
  offset:  1032 sectors
  size:    2930270970 sectors
  mode:    read/write

Make sure you keep track of when to use /dev/mapper/freeagent vs /dev/sdc1 in the commands above.

8 Levels of IT Security

Via: Wikibon