[U-Boot] verifying & signing

[Srinivasan S]

Hi Simon,

Good Morning!

Many Thanks a lot for all your support so far,

1. With respect to the verified boot , I want to put the images onto NAND FLASH, Could you please let me know what is the procedure of flashing  the verified boot images onto NAND instead of micro-SD

2.Does dm-verity works only on read-only rootfs?.. or it works on read-write rootfs?.. because as of  now we are looking out only for a bare minimal rootfs , could you please suggest me if any rootfs with minimal support where dm-verity can be applied & verified apart from android

 I want to implement the automatic software update & recovery feature (ie., firmware update of uboot, kernel & rootfs) in ti-sdk-am335x-evm-07.00.00.00 BSP's , if in case if it bricks to unbrick by itself,
 Could you please help me with suitable pointers & source code links for implementing this feature

Awaiting for your replies
Many Thanks in advance again,

Srinivasan S


________________________________________
From: sjg at google.com <sjg at google.com> on behalf of Simon Glass <sjg at chromium.org>
Sent: Monday, November 3, 2014 5:08 AM
To: srinivasan
Cc: U-Boot Mailing List; Srinivasan S
Subject: Re: verifying & signing

Hi,

On 2 November 2014 07:06, srinivasan <srinivasan.rns at gmail.com> wrote:
>
>
>
>
> Hi Simon,
>
> http://lists.denx.de/pipermail/u-boot/2014-June/180845.html
>
> As the above link explains the Signing of kernel & verifying with uboot,
>
> Could you please let me know do you have any methods of signing & verifying
> the linux kernel with root file system ie., am using
> ti-sdk-am335x-evm-07.00.00.00 BSP's where linux kernel is from this BSP only
> & would be planning to use rootfs as my Angstrom filesystem or any others

If you use dm-verity you can verify your root disk using a hash which
is stored in the verified part of U-Boot. This is the method used by
Chrome OS. This requires a read-only rootfs though. Is that
acceptable?

See this page for some info on how Android does this:

https://source.android.com/devices/tech/security/dm-verity.html

>
> Could you please let me know how do we sign & verify the kernel with rootfs
> with detailed steps as am using beaglebone black as my development board
> with ti-sdk-am335x-evm-07.00.00.00 BSP's

I don't have details steps of this part sorry. An overview is here:

http://events.linuxfoundation.org/sites/events/files/slides/chromeos_and_diy_vboot_0.pdf


>
> Awaiting for your replies
> Many Thanks in advance
>
>
>

Regards,
Simon