[U-Boot-Users] Secure Firmware + Firmware Upgrade?

Wolfgang Denk wd at denx.de
Mon Jun 5 10:57:25 CEST 2006

In message <op.tange7swdfxu59 at sys.t-mobile.de> you wrote:
> Sorry for not being verbose, here I meant that if the boot bit flag is not
> set it would imply that the firmware upgrade failed and its not safe to
> boot. It would than wait to load the firmware via kermit protocol. This

In which way not safe? We have pretty good image protection using CRC
checksums. What sort of additional security do you want to gain  with
this additional bit? I don't understand...

> > You are aware that this is not really secure in any way, as it leaves
> > many ways to run random unsigned images, too?
> In my case the firmware upgrade is not secure that is my requirement is >  > 
> not to check
> if the firmware being replaced is authentic or not, it is the signed  > 
> firmware that matters.

Your product  will  include  GPLed  boot  loader.,  i.  e.  you  must
accompany  it with a written offer to give any third party a complete
copy of the corresponding source code. If I want to run my own code I
will just disable the "authenticity tests" in U-Boot and  install  my
own, free boot loader. Or I'll craft an image that passes your tests.

> Am sorry if i wasn't clear in letting you explain the same before. Do yo> u  > 
> still feel that its possible
> to tamper and by pass the security unless ofcourse if boot-script-image > is  > 
> manipulated?

Yes of course it is possible to boot my own custom images. There  are
several  ways  to  do  this.  And  I  intentionally  avoid  the  term
"tampered" here, because it does not apply. If I own the hardware,  I
have every right to run any software I like on it.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Actual war is a very messy business. Very, very messy business.
	-- Kirk, "A Taste of Armageddon", stardate 3193.0

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