On Thu, 2002-09-26 at 08:52, James Gritton wrote:
> After playing with a few encrypted filesystems, and giving up on them (after
> a kernel crash or two), I went looking for something else to encrypt.  The
> logical choice is the device.

Have you seen ports/security/vncrypt?

I use ports/security/cfs which uses a loopback NFS server to decrypt a
backing directory for you. It is nice because it expands on the fly but
it isn't a speed demon.

> Well, the virtual device.  Like a cryptfs that's based on a loopback mount,
> I'm encrypting a virtual device based on the "vn" driver.  This was only a
> few hours' work, though it's admittedly incomplete.  This is based on the
> Blowfish code in the kernel used by ipsec and such, which an extra ioctl
> added to set the key.  Only three source files require modification:
> 
> sys/sys/vnioctl.h:
>   Define the VNIOCSETKEY ioctl
> 
> usr.sbin/vnconfig/vnconfig.c:
>   Add a "-k" option to specify that an encryption key should be entered via
>   getpass(), and passed in with the above ioctl.
> 
> sys/dev/vn/vn.c
>   Add a blowfish key entry to the softc structure.  This is set via the
>   above ioctl, which converts a passed-in string into the key data.
>   Encryption is done around the vn's VOP_READ and VOP_WRITE calls, in
>   512-byte CBC chunks.
> 
> That's it - 90 lines of new code.  This is for my purposes complete and
> working, which is to say neither is quite true.  For production-quality
> code, some work remains:

Impressive :)

-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 9A8C 569F 685A D928 5140  AE4B 319B 41F4 5D17 FDD5


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