CyberMan Software

Home	Linux	LEAF	Logger	UU Coder
Code64	Nuke	Websites	Contact	Graphical

printer-friendly page Terms of use:

Harvesting e-mail addresses from this website for Unsolicited Commercial E-mail (UCE) is strictly prohibited. UCE (aka SPAM) sent to any e-mail address in the cybermansoftware.com domain will be assumed to have been sent with the intent to harass or annoy. It may be prosecuted as a criminal offense under NY State Penal Code Section 240.30.

CMS Linux Details

Differences from Red Hat
How to use encrypted filesystems
Package differences from Red Hat
Descriptions of packages in CMS Linux 2.4.18
Commercial ideas
Order form for CyberMan Software products
CyberMan Software products on eBay (may occasionally include personal property of CyberMan Software Proprietor Max Kessler)
CMS Linux Bumper Sticker $1.50
Screen Shots of several utilities that come with CMS Linux

CMS Linux is a new Linux distro based on Red Hat 7.3, but with several of Red Hat's idiosyncrasies fixed. Major differences are summarized as follows:

Differences from Red Hat

The security compromised version of OpenSSL has been replaced.
Much internationalization has been removed.
All of the high-end server / cluster stuff has been removed.
- Apache and some of its modules remain. What college student doesn't want to run a website from his/her dorm room?
- FTP, Telnet, Samba, NFS, and SSH servers remain, so users at least have an option of accessing their machines remotely, but are disabled by default.
Several games and other desktop applications have been added.
The kernel and util-linux related packages have been patched to include support for encrypted filesystems.
The default shell has been changed to TCSH, because there's no point in making a user-friendly desktop and still using an archaic second generation Bourne shell.
dd has options quiet=[0|1] and hash=N added. If you use dd, then see the man page for details.
The effect of useradd's '-n' option has been negated. Most home users have no need to create a different group for every user. If a user wants to share files with some, but not all other users, then a group can be added.
Note: This may cause incompatability with a small handfull RPM's built for Red Hat. If a package adds a system account and requires a group for that account, then the RPM needs to be rebuilt as follows.
- Download the source RPM. (filename ending with '.src.rpm')
- Type the command:
  rpm -i <packagename-version>.src.rpm
- Edit the file /usr/src/cyberman/SPECS/<packagename>.spec to add a '-n' option to each line containing '/usr/sbin/useradd'.
- Type the following 2 commands:
  rpm -ba /usr/src/cyberman/SPECS/<packagename>.spec
  rpm -i /usr/src/cyberman/RPMS/i386/<packagename-version>.i386.rpm
  or
  rpm -i /usr/src/cyberman/RPMS/noarch/<packagename-version>.noarch.rpm

[ Top of page ]

How to use encrypted filesystems

Disclaimer: These instructions are provided as they work on my system. They may or may not work on yours. They are provided without warranty or guarantee of any kind whatsoever. Their use, if you use them, is entirely your own responsibility.

Q: How do I make an encrypted floppy disk?
A: To make a brand spanking new disk:

Insert a blank disk. (duh)
As the root user, type:
1. modprobe cipher-<ciphername>
2. losetup -e <ciphername> /dev/loop0 /dev/fd0 (You will be prompted for a password and other necessary information, depending on the cipher used.)
3. dd quiet=1 if=/dev/urandom of=/dev/loop0
4. mkfs -t ext2 (or vfat, if you prefer) /dev/loop0
Now that an encrypted filesystem is set up, you can mount it with 'mount -t auto /dev/loop0 /mnt/floppy'.
When you are done, don't forget to:
- umount /mnt/floppy (This should be done for regular floppies as well.)
- losetup -d /dev/loop0 (Important: This clears the encryption and your password.)
- modprobe -r cipher-<ciphername> (This removes the kernel module used to encrypt the data.)

A: To encrypt an existing disk:

Insert your existing disk. (duh)
Follow steps 1 and 2 above.
To encrypt the disk, type 'dd quiet=1 if=/dev/fd0 of=/dev/loop0'. (By default dd reads and writes 512 byte blocks at a time and the crypto modules encrypt 512 byte blocks at a time, so encrypting data in place like this should be safe.)
You can access the disk by setting up the encryption as in steps 1 and 2 above, then mounting the disk by typing 'mount -t auto /dev/loop0 /mnt/floppy'.
When you're done, clean up as described above.

Q: How do I change my password or use a different cipher?
A: To change your password:

Insert the disk. (duh)
If you wish to change the cipher, type 'modprobe cipher-<newciphername>'
Setup encryption as described in steps 1 and 2 above, but do not mount the disk.
Type 'losetup -e <ciphername> /dev/loop1 /dev/fd0'. (If you are changing the cipher use the new cipher name.)
Type 'dd quiet=1 if=/dev/loop0 of=/dev/loop1'. (See the comment under 'To encrypt an existing disk' above.)
Clean up.

Q: How do I encrypt a hard disk partition?
A: The same way you encrypt a floppy disk, except:

Encrypting the / partition or /boot partition is beyond the scope of this document as it requires significant hacking.
Encrypting standard system partitions is not recommended as the partition cannot be used until encryption has been setup and encryption must be setup the whole time the partition is being used.
If you have a non-system filesystem on partition /dev/hda7, for example, just replace /dev/fd0 with /dev/hda7 in the floppy disk examples above.

A: You can store encrypted data in a regular file, instead of a partition:

For a 1 GB filesystem, for example, type 'dd quiet=1 bs=1024 count=1048576 if=/dev/zero of=cryptfile'. (1 kB = 1024 bytes, 1 MB = 1024 kB, 1 GB= 1024 MB, therefore 1 GB=1024*1024=1048576 kB.)
Setup encryption using cryptfile in place of /dev/fd0.
Make a filesystem on /dev/loop0 as described above.
Clean up when you're done.

Q: How do I allow non-root users to use encrypted filesystems?
A: Add the following lines to the file '/etc/sudoers':

<username> ALL=/sbin/modprobe cipher-[A-Za-z0-9]*
<username> ALL=/sbin/modprobe -r cipher-[A-Za-z0-9]*
<username> ALL=/sbin/modprobe -r crypto[a-z]*
<username> ALL=/bin/mount -t [A-Za-z0-9]* /dev/loop[0-7] /mnt/floppy
<username> ALL=/bin/umount /dev/loop[0-7]
<username> ALL=/sbin/mkfs -t [A-Za-z0-9]* /dev/loop[0-7]

The user <username> can then type 'sudo' before each command that requires root access.

[ Top of page ]

Home	Linux	LEAF	Logger	UU Coder
Code64	Nuke	Websites	Contact	Graphical

Privacy Policy:

Absolutely no personally identifiable information is collected about your visit to this website. If, however, you choose to contact CyberMan Software or participate in a contest, then only information that is necessary to reply to you or deliver your prize is collected. No information will ever be shared with anybody else, except as legally required. Period.