[coreboot] 3 Chip Open BIOS + ESP: Backup/Secure BIOS with Redundancy

[Nathaniel Dube]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Thursday 12 June 2008 02:46:19 am you wrote:
> 1. If Chip 1 is read only, and something happens, chips 2 and 3 are
> restored to whatever version they were originally, leaving chips 2 and
> 3 open to the same vulnerability, should it not be eradicated from the
> hard drive or fixed by an update.

Having the read only Backup-BIOS wipe the writable BIOS is simply a last case 
scenario.  It's a last line of defense incase your primary BIOS becomes 
foobar.  Keep in mind you would also have a software antivirus and firewall 
running on your operating system.  So if the malware happens to get through 
that it would then have to deal with the hardware rootkit protection in the 
mother board.  When ever you boot, the BIOS would use a checksum to check it 
self for modifications.  I could be wrong but I believe there are similar 
security protocols in SELinux and similar technologies to detect if the Linux 
kernel has been screwed with.

> 2. Without some sort of extremely efficient compression algorithm,
> Chip 1 would have to be as large as Chip 2 + 3. I'm guessing it would
> probably end up being 4 chips, all the same size.

I suppose I could make it little more simple and just have 2 chips.  One would 
be a backup and one for primary use.  I have a little flash drive in my 
pocket right now, it's 8 GB.  I'm sure we can design a sufficiently big 
enough chip to store the necessary software.

> 3. How is Chip 3 to determine what network to connect to? Can you
> really fit a networking stack, dhcp client, and secure ftp client into
> 1 or 2MB or less? How much time would be added to the boot time for
> Chip 3 to identify a network, connect to it, get an IP, and then check
> the versioning and potentially download an update and apply it?

Sure, why not.  If you want 100% guarantee, then don't ever use the internet.  
If we can figure out how to buy stuff offline with strong enough encryption 
with a big enough margin of safety, I'm sure we can figure out something on 
how to download updates.

> 4. What happens if the download server is compromised? Or if the
> download location is forced to move? Do you really like the idea of
> writing down 75 character web addresses so you can type them in to a
> BIOS (or rather, payload) configuration menu, to change an update
> path? What happens if Chip 3 needs to get restored?

I really don't see that happening.  I don't remember ever having any issues 
with download patches for openSUSE.  Now that I mention it, the people at 
Novell have their main update domain bounce you to random mirrors.  So when 
you download updates, you're not allways getting them from the same system.  
Just incase one goes down it'll bounce you to a different mirror.  Which 
means you don't have to waste time changing URLs for your updates.  Also, the 
RPM packages are signed with GPG keys from the people who manage the 
repositories you're downloading from.  It's to help protect you incase the 
servers are compromised. ;-)

> 5. How does this protect against malicious/infected PCI roms?

It would be possible in theory that when you install new hardware that have 
writable ROMs (video card maybe I'm not sure there are any that are writable) 
that your mother board makes a checksum of that ROM's firmware.  So on a next 
reboot your mother board does a quick check to see if there where any changes 
and alert you if there is.  Now if we could make this board really clever we 
could give it enough room to make backups as well as checksums of all the 
firmware off all your hardware.  Then if something is changed it could either 
ask you if you want to restore from backup or incase of stupid users have it 
set to do it automatically.

> 6. Do you honestly believe your brother's type of ignorance can be
> fixed by a more secure BIOS?

There is no simple fix for stupidity but to go for a car metaphore for a 
moment.  You have locks and keys for your house and car.  Sure, if some 
people wanted to bad enough they can just break the window hot wire your car 
and drive off or pick the lock on your house and steal your TV.  Then you can 
install a car alarm and a GPS for the cops and install a security system in 
your house.  It's a cat and mouse game.  Persistant people will find ways 
around almost any locked door.  But that's no excuse not to lock your door.  
While security may not keep every one out, it'll keep more people out then if 
you use nothing at all. ;-)

> Seriously, the type of people who have 
> those kinds of problems, viruses and malware running amuck, would
> never realize their BIOS had a problem, wouldn't open their case to
> realize there's a switch on the board, and probably wouldn't even read
> the manual to find out it was there or what it did.

Instead of a jumper I suppose you can design it to be automatic in the 
instance the writable BIOS failed a cheksum.  The system would then reboot it 
self, restore from backups after wiping the infected BIOS, download updates 
for rkhunter and clamav.  Then the BIOS would force clamav to scan the system 
for infection.  Most of this can be done automatically in a clever way in the 
same way scandisk runs on windows if you shut it down wrong.  Something 
similar hapens on Linux.

Now I'm not suggesting a really long boot process every time you turn on the 
system.  On every boot it would only check the BIOS for modification and 
maybe the MBR then continue on it's marry way.  All this it meant to do is 
help protect against rootkits.  This could also help serve as a protection 
measure against failed BIOS flashes to update the BIOS.  Which has happened 
to me before.  I ordered a board for my dad and noticed the BIOS was out of 
date.  I followed the directions to the letter.  Downloaded the updates from 
the companies site attempted to flash the system.  Everything appeared to 
work.  But when I rebooted the damn thing all I got was a black screen.

Now if mother boards had been built with a second read only chip as a backup 
to restore from I wouldn't have waisted days sending it back in the mail 
telling them it was DOA so I can get another one.

> Proper antivirus software, malware protection, and a decent firewall, 
combined with reflashing the BIOS every once in a while, can give exactly the 
same result.

This might work for people like you and me but this wont work for the average 
person.

> I know several people who had me work on their computers, back 
> when windows 98 and ME were the current versions, they were having
> horrible problems with their computers running slow, this file or that
> was missing/damaged, etc. Come to find out, in at least half a dozen
> cases, they were canceling scandisk every time the computer started.

I find most people do that with everything that seems to be a boundary between 
them and what they really feal like doing on the computer. If it comes to 
taking maybe 10 seconds to read a security alert from their antivirus or 
firewall or spending that 10 seconds on myspace they'll choose myspace every 
time and just click what every to make the window go away.  Which is what my 
brother did with his firewall and ended up blocking all traffic.  He couldn't 
figure out what magical beast broke his internet so he managed to uninstall 
the firwall all together which took the antivirus with it.  Which is how he 
ended up infected with more viruses then a Nigerian hooker.  I had to tell 
him to stop using limewire and if he insisted on downloading stuff to learn 
how to use bittorrent.

> Let it run, and in every case, problem solved. What happens when your
> rootkit detection program realizes the BIOS is messed up, and asks the
> user to get down on their hands and knees, dig the computer out of the
> desk they so lovingly hid it in, open the case, flip a switch, get it
> all back together so they can restart it, wait 5 minutes, and repeat?

As I said above, a more clever system will do it all automatically.  If you 
shut down most operating systems improperly they're smart enough to run 
software to scan the file system for damage on the next reboot.  Perhaps my 
idea is overly complicated, but the point I was trying to make still stands.  
This is the 21st century, mother boards need to be taking a more active role 
in protecting them selves from the crap that's out there.  Because stupid 
users isn't going to do it for them.

> I'm not an engineer either, yet, working on my degree, I'm just trying
> to give you some things to consider. You should also consider that
> vendors don't like spending any more money then they absolutely have
> to, so adding 2 or 3 redundant chips is not cool. Also, most current
> hardware only supports one flash chip, or else 2 flash chips but on 2
> different interfaces (SPI and LPC, for example).

Hardware manufactories need to get off their lazy a$$es and start innovating.  
Oh well, there's always the technological singularity to look forward to.  
Then machines can fix them selves and not rely on stupid users.  Some times I 
wish the Matrix was reality.  A lot of people out there deserve to be turned 
into batteries. ;-)
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.4-svn0 (GNU/Linux)

iD8DBQFIUP3qvsn/sQCIOqQRAsrDAJ0c3Ls2SWFLW+OgHqxjJuGzcmv0cgCcD7uZ
GFi/3lCpnVf7ig4Z1RVWd+I=
=UBPq
-----END PGP SIGNATURE-----