Maintaining Cloudera Navigator Encrypt

Backing Up Navigator Encrypt

Perform backups of encrypted data, mount points, and the Navigator Encrypt configuration directory (/etc/navencrypt) on a regular basis.

Access Modes

Navigator Encrypt provides three different access modes:
  • Enforcing is the default mode in which Navigator Encrypt validates access from all processes against the ACL. To protect your data, enforcing mode must be enabled.
  • Permissive mode causes action="denied" messages to be logged in dmesg. It does not prevent access to the encrypted data. This mode is a dry-run feature to run and build ACL rules.
  • Admin mode, as well as permissive mode, does not prevent access to the encrypted data. It allows any process to access the information because the ACL rules are not validated against the process. Admin mode does not cause action="denied" messages to be logged in dmesg.
To view the current access mode, run the following command:
$ sudo /usr/sbin/navencrypt status -d
To change the access mode, use the following command:
$ sudo /usr/sbin/navencrypt set --mode={enforcing|permissive|admin}

You cannot change the Navigator Encrypt access mode unless the Navigator Encrypt module is running. To view the status of the Navigator Encrypt module, run navencrypt status --module.

To start the Navigator Encrypt module there must be at least one active mount-point. To verify the mount-points status, run the following command:
$ sudo /etc/init.d/navencrypt-mount status
For RHEL 7, use systemctl instead:
$ sudo systemctl status navencrypt-mount

Changing and Verifying the Master Key

You can perform two operations with the navencrypt key command: change and verify.

You can verify a key against the Navigator Encrypt module, the Navigator Key Trustee server, or both. For example:
$ sudo /usr/sbin/navencrypt key --verify
$ sudo /usr/sbin/navencrypt key --verify --only-module
$ sudo /usr/sbin/navencrypt key --verify --only-keytrustee
The master key can be changed in the event that another key-type authentication mechanism or a new master key is required. Valid master key types are single-passphrase, dual-passphrase, and RSA key files. To change the master key type, issue the following command and follow the interactive console:
$ sudo /usr/sbin/navencrypt key –-change

You can use the --trustees, --votes, and --recoverable options for the new key as described in Registration Options.

Updating ACL Fingerprints

All rules reference a process fingerprint (a SHA256 digest) that is used to authenticate the process into the file system. If the filesystem detects a fingerprint that is different from the one stored in the ACL, the Linux process is denied access and treated as an untrusted process.

Occasionally this process fingerprint must be updated, such as when software is upgraded. When the fingerprint must be updated, the Navigator Encrypt administrator re-authenticates the process on the ACL by executing the command navencrypt acl --update.

The following example demonstrates how to determine when a process fingerprint has been changed and must be updated:
$ sudo /usr/sbin/navencrypt acl --list
Type MASTER passphrase:
# -  Type Category    Path         Profile  Process
1 !! ALLOW @mysql *            /usr/sbin/mysqld
2 ALLOW @log * /usr/sbin/mysqld
3 !! ALLOW @apache * /usr/lib/apache2/mpm-prefork/

In the example above, the double exclamation (!!) characters indicate that a process fingerprint has changed and must be updated. Similarly, double E (EE) characters indicate a process read error. This error can be caused by a process that does not exist or that has permission issues.

Managing Mount Points

The /etc/init.d/navencrypt-mount command mounts all mount points that were registered with the navencrypt-prepare command and are listed in the /etc/navencrypt/ztab file. The possible operations are:
  • start
  • stop
  • status
  • restart

For RHEL 7, use systemctl [start|stop|status|restart] navencrypt-mount.

When executing the stop operation, the encrypted mount point is unmounted, and your data becomes inaccessible.

The following example shows how to execute navencrypt-mount status with some inactive mount points:
$ sudo /etc/init.d/navencrypt-mount status
The following example shows how to execute the navencrypt-mount stop command:
$ sudo /etc/init.d/navencrypt-mount stop
The following example shows how to execute the navencrypt-mount start command:
$ sudo /etc/init.d/navencrypt-mount start
Here is an example command used to manually mount a directory:
$ sudo /usr/sbin/mount.navencrypt /path/to_encrypted_data/ /path/to/mountpoint

This command can be executed only if the navencrypt-prepare command was previously executed.

Allowing Access to a Single Operation

Sometimes running a single operation on encrypted data is required, such as listing the encrypted files or copying a particular file. The navencrypt exec command provides an efficient method to accomplish this. In the following command example, permission is denied when the command is run without navencrypt exec:
$ ls /mnt/db_encrypted/mysql/
ls: cannot open directory /mnt/db_encrypted/mysql/: Permission denied
If the ls command is executed with navencrypt exec, access is allowed one time only:
$ sudo /usr/sbin/navencrypt exec "ls -l /mnt/db_encrypted/mysql/"

Navigator Encrypt Kernel Module Setup

If the kernel headers were not installed on your host, or if the wrong version of the kernel headers were installed, the Navigator Encrypt module was not built at installation time. To avoid reinstalling the system, install the correct headers and execute the navencrypt-module-setup command. This attempts to build the module and install it.

This method is also an efficient way to install any new Navigator Encrypt module feature or fix without otherwise modifying your current Navigator Encrypt environment.

Navigator Encrypt Configuration Directory Structure

The file and directory structure of /etc/navencrypt is as follows:
$ tree /etc/navencrypt/
/etc/navencrypt/
├── control -> /etc/navencrypt/jSpi9SM65xUIIhrau1Nn8ZXmQhrrQ9e363EUz8HKiRs
├── jSpi9SM65xUIIhrau1Nn8ZXmQhrrQ9e363EUz8HKiRs
├── rules
├── ztab
locust
└── keytrustee

├── clientname

├── deposits

│   ├── dev.loop0

│   ├── media.31E5-79B9locustlocust[system ~]# . /etc/*release[system ~]# . /etc/*release

│   ├── mnt.a

│   ├── mnt.encrypted

│   └── mnt.tomount

├── pubring.gpg

├── pubring.gpg~

├── random_seed

├── secring.gpg

├── trustdb.gpg

└── ztrustee.conf
The following files and folders are part of the created file structure:
  • control

    File that saves information about the mount points and corresponding Navigator Key Trustee keys.

  • rules

    File that contains the ACL rules. It is encrypted with the user-provided master key.

  • ztab

    File that contains information about all the mount points and their encryption type.

  • keytrustee

    Directory where Navigator Key Trustee GPG keys are stored. These are generated during navencrypt register operations.

  • keytrustee/deposits

    Directory where the Navigator Encrypt keys are saved. These are encrypted with the user-provided master key.

Every mount point has an internal randomly-generated encryption passphrase.

Upgrading Navigator Encrypt Hosts

See Best Practices for Upgrading Navigator Encrypt Hosts for considerations when upgrading operating systems (OS) and kernels on hosts that have Navigator Encrypt installed.