Announce loop-AES-v1.4d file/swap crypto package

Announce loop-AES-v1.4d file/swap crypto package

[Jari Ruusu]

[linux-kernel also CC'd due to recent encrypted swap discussion]

In short: If file and swap crypto is all you need, this package is a hassle
free replacement for international crypto patch and HVR's crypto-api.

This package provides loadable Linux kernel module (loop.o) that has AES
cipher built-in. The AES cipher can be used to encrypt local file systems
and disk partitions. For more information about compiling and using the
driver, see the README file in the package.

Features:
- GPL license.
- No source modifications to kernel. No patch hassles when you are upgrading
  your kernel.
- Works with all recent 2.4, 2.2 and 2.0 kernels, including distro vendor
  kernels. Encrypted disk images are compatible across all supported
  kernels.
- AES cipher is used in CBC mode. Supports 128, 192 and 256 bit keys.
- Passwords hashed with SHA-256, SHA-384 or SHA-512.
- 512 byte based IV. IV is immune to variations in transfer size and does
  not depend on file system block size.
- Device backed (partition backed) loop is capable of encrypting swap on 2.4
  kernels.

Changes since previous release:
- Little speed optimization in aes-glue.c
- External encryption module locking bug is fixed (kernel 2.4 only). This
  bug did not affect loop-AES operation at all. This fix is from Ingo
  Rohloff.
- On 2.4 kernels, device backed loop maintains private pre-allocated pool of
  RAM pages that are used when kernel is totally out of free RAM. This
  change also fixes stock loop.c sin of sleeping in make_request_fn().

Kernel 2.4 users who want to encrypt swap partitions should upgrade to this
version. No need to upgrade if you use older 2.2 or 2.0 kernels.

bzip2 compressed tarball is here:

    http://loop-aes.sourceforge.net/loop-AES-v1.4d.tar.bz2
    md5sum 404f82796bacc479deb266f13ec260b8

PGP signature file, my public key, and fingerprint here:

    http://loop-aes.sourceforge.net/loop-AES-v1.4d.tar.bz2.sign
    http://loop-aes.sourceforge.net/PGP-public-key.asc
    1024/3A220F51 5B 4B F9 BB D3 3F 52 E9  DB 1D EB E3 24 0E A9 DD

Regards, 
Jari Ruusu <jari.ruusu@pp.inet.fi>

Re: Announce loop-AES-v1.4d file/swap crypto package

[Eyal Lebedinsky]

Jari Ruusu wrote:
> In short: If file and swap crypto is all you need, this package is a hassle
> free replacement for international crypto patch and HVR's crypto-api.

Some comments about the packaging (which I made once before).

1) It claims to allow you to specify the kernel sources dir, but it then
runs 'depmod' without a nominated version which is only valid if you
are building for the running kernel. I now have it doing
        depmod -ae $(KERNELRELEASE)

2) 'make' will also install the module. It would be nice to have an
explicit 'make install' instead.

3) The module is installed as loop.o, same as the standard kernel
module. I prefer to use different names for added modules.

Also, it ends up in
        /lib/modules/VERSION/block/loop.o
which is fine for 2.2, but 2.4 uses
        /lib/modules/VERSION/kernel/drivers/block/loop.o
so you now have two loop.o - do you know which one will be loaded?

I changed it to install as loop-aes.o:
        cp -p loop.o $(ML)/kernel/drivers/block/loop-aes.o
and I can now select a module in the modules config.

--
Eyal Lebedinsky (eyal@eyal.emu.id.au) <http://samba.anu.edu.au/eyal/>

Re: Announce loop-AES-v1.4d file/swap crypto package

[Jari Ruusu]

Eyal Lebedinsky wrote:
> Jari Ruusu wrote:
> > In short: If file and swap crypto is all you need, this package is a hassle
> > free replacement for international crypto patch and HVR's crypto-api.
> 
> 1) It claims to allow you to specify the kernel sources dir, but it then
> runs 'depmod' without a nominated version which is only valid if you
> are building for the running kernel. I now have it doing
>         depmod -ae $(KERNELRELEASE)

I will fix that in next release. However, most systems (if not all) run
depmod from bootup initialization scripts. Depmod from the Makefile is only
needed when you intend to use the driver immediately without rebooting.
 
> 2) 'make' will also install the module. It would be nice to have an
> explicit 'make install' instead.

Getting kernel Makefile to jump back to loop-AES directory for "make
install" is easy for 2.4 kernels, but not so easy for 2.2 and 2.0 kernels.
It makes sense to have identical build instructions for all supported
kernels.
 
> 3) The module is installed as loop.o, same as the standard kernel
> module. I prefer to use different names for added modules.

It is a replacement for kernel's loop.o driver. Actually, it _is_ kernel's
loop.c patched and compiled outside of kernel tree. My patch just fixes
known bugs in stock loop.c and pre-registers AES transfer.
 
> Also, it ends up in
>         /lib/modules/VERSION/block/loop.o
> which is fine for 2.2, but 2.4 uses
>         /lib/modules/VERSION/kernel/drivers/block/loop.o
> so you now have two loop.o - do you know which one will be loaded?

Loop-AES build instructions _require_ you to disable the loop driver in the
kernel. If you have two loop.o drivers, you skipped some build instructions.
Also, it can't be placed in /lib/modules/VERSION/kernel/drivers/block/loop.o
because kernel's "make modules_install" will remove all non-configured
drivers from there. If it was placed there, it would disappear next time you
recompile and reinstall other kernel modules.
 
> I changed it to install as loop-aes.o:
>         cp -p loop.o $(ML)/kernel/drivers/block/loop-aes.o
> and I can now select a module in the modules config.

If the module name is loop.o then kmod will automatically load it to kernel
when needed (assuming that CONFIG_KMOD=y). That way, there is no need to
modprobe or insmod it. Just use it, and it will be there when you need it.
 
Regards,
Jari Ruusu <jari.ruusu@pp.inet.fi>

Re: Announce loop-AES-v1.4d file/swap crypto package

[Eyal Lebedinsky]

Jari Ruusu wrote:
> 
> Eyal Lebedinsky wrote:
> > Jari Ruusu wrote:
> > > In short: If file and swap crypto is all you need, this package is a hassle
> > > free replacement for international crypto patch and HVR's crypto-api.
> >
> > 1) It claims to allow you to specify the kernel sources dir, but it then
> > runs 'depmod' without a nominated version which is only valid if you
> > are building for the running kernel. I now have it doing
> >         depmod -ae $(KERNELRELEASE)
> 
> I will fix that in next release. However, most systems (if not all) run
> depmod from bootup initialization scripts. Depmod from the Makefile is only
> needed when you intend to use the driver immediately without rebooting.

Problem is that one gets tons of errors due to the use of the wrong
kernel.
The exact way for doing it right is actually:
	depmod -ae $(KERNELRELEASE) -F $(LS)/System.map

> Loop-AES build instructions _require_ you to disable the loop driver in the
> kernel. If you have two loop.o drivers, you skipped some build instructions.

It is not in the kernel, it is in my /lib/modules as it was built
originally.
I want to keep it there while I play with the new module, and not lose
the
original. Naturally, just my preference, not everybodies.

--
Eyal Lebedinsky (eyal@eyal.emu.id.au) <http://samba.anu.edu.au/eyal/>

Re: Announce loop-AES-v1.4d file/swap crypto package

[Jari Ruusu]

Eyal Lebedinsky wrote:
> Problem is that one gets tons of errors due to the use of the wrong
> kernel.
> The exact way for doing it right is actually:
>         depmod -ae $(KERNELRELEASE) -F $(LS)/System.map

Yep, but one must define KERNELRELEASE for 2.0 kernels. As I said, I will
fix this for next release.

> > Loop-AES build instructions _require_ you to disable the loop driver in the
> > kernel. If you have two loop.o drivers, you skipped some build instructions.
> 
> It is not in the kernel, it is in my /lib/modules as it was built
> originally.
> I want to keep it there while I play with the new module, and not lose
> the
> original. Naturally, just my preference, not everybodies.

I meant that loop must be completely disabled, as it says in the README:

CONFIG_BLK_DEV_LOOP=n

Regards,
Jari Ruusu <jari.ruusu@pp.inet.fi>