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Encrypted filesystems and util-linux

Ok, so I have an encrypted ext2 filesystem inside a disk file (~/.crypto). Up until now, it's been working perfectly with the following line in fstab:
/home/stephen/.crypto /mnt/crypt ext2 defaults,noauto,loop,encryption=aes,user 0 0

I typed mount /mnt/crypt, and it asked for a keysize and password.

Now, however, I get the following message:
You must specify a key size (in bits) for use with CryptoAPI encryption.

The only thing I can think of that's changed is that I upgraded util-linux (to 2.12-r4). My kernel hasn't changed; it's still 2.4.20-gentoo-r9.

The file Documentation/cryptoapi/cryptoloop.txt in the kernel source tree suggests adding the option -k 128 to the losetup command line, but then losetup complains about invalid option -- k.

Can anyone suggest what's changed here? Has upgrading util-linux changed something important?

I'm not sure if util-linux changed anything important. Did you end up changing any configs while installing util-linux?

If the "-k" option isn't accepted, look for the program mount calls upon to mount the encrypted loopback filesytem. Look up man and info entries for that program for something equivalent to the "-k" option, such as a way to specify key size on the command line. For all we know, the correct syntax could be "--k".

When faced with gentoo-specific problems like this, I usually meet with better success at http://forums.gentoo.org where more people know what they're talking about in terms of Gentoo.

@thebell

Do you found a solution?

I have "Linux redhat 2.6.5-1.358 #1 Sat May 8 09:04:50 EDT 2004 i686 athlon i386 GNU/Linux" / Fedora Core2. I installed the newest util-linux Version 2.12a, with no success.

I think i need a "international" kernel patch, but there is no avaible for 2.6.5.

My old rh8 linux, with "-k" support:

Code:

# uname -a

Linux Samba 2.4.18-14 #1 Wed Sep 4 13:35:50 EDT 2002 i686 athlon i386 GNU/Linux

# losetup

usage:

  losetup loop_device                                      # give info

  losetup -d loop_device                                  # delete

  losetup [ options ] loop_device file                    # setup

    where options include

    --offset <num>, -o <num>

        start at offset <num> into file.

    --pass-fd <num>, -p <num>

        read passphrase from file descriptor <num>

        instead of the terminal.

    --encryption <cipher>, -e <cipher>

        encrypt with <cipher>.

        Check /proc/crypto/cipher for available ciphers.

    --keybits <num>, -k <num>

        specify number of bits in the hashed key given

        to the cipher.  Some ciphers support several key

        sizes and might be more efficient with a smaller

        key size.  Key sizes < 128 are generally not

        recommended

    --phash <hash>, -P <hash>

        specify <hash> to use for hashing the passphrase

        (supported: rmd160old, sha256, sha384, sha512)

new fedora c2:

Code:

 

#uname -a

Linux redhat 2.6.5-1.358 #1 Sat May 8 09:04:50 EDT 2004 i686 athlon i386 GNU/Linux

#losetup

  losetup loop_device                                      # give info

  losetup -d loop_device                                  # delete

  losetup [ -e encryption ] [ -o offset ] loop_device file # setup