iMX6 ull encrypted boot

[CarlosFG]

I'm trying to enable encrypted boot in iMX6 ULL EVK. According to IMX6ULLRM and IMX6ULLSRM this should be possible. One of the steps to get encrypted boot work is generate a "dek blob" [1][2] inside the processor. In order to do that, there is a u-boot command named "dek_blob" that uses the CAAM [1][3][4]. I couldn't get his command work, It fails at this point in a function named caam_page_alloc() which is always called with the same parameters: caam_page_alloc(1, 1), this means it fails regardless of how I use the dek_blob command. I also tried to use the CAAM Linux drivers unsuccessfully. Later I found in a couple of sites the CAAM is not available in iMX6ULL [5][6]

So my question is ¿How can I encapsulate a DEK and obtain a dek blob in the iMX6ULL?

1. Code-signing Tool User's Guide
2. AN12056
3. U-boot introduction to HABv4
4. U-boot encrypted boot
5. https://community.nxp.com/t5/i-MX-Processors/Signed-and-encrypted-boot-in-i-MX6UL/m-p/466447/highlig...
6. https://patchwork.kernel.org/project/linux-arm-kernel/patch/1523739330-27363-1-git-send-email-festev...

[igorpadykov · Accepted solution]

Hi CarlosFG

unfortunately i.MX6ULL does not support encrypted boot.

Best regards
igor

[CarlosFG]

Thanks you very much igorpadykov.

The Applications Processor Reference Manual for this device (IMX6ULLRM) says the encrypted boot is supported. I humbly suggest to amend it in order to avoid other engineers waste their time trying to make it work.

[igorpadykov]

Hi CarlosFG

in theory it can be supported, but in practice NXP software implementation currently

supports only CAAM based options.

Best regards
igor

[mprt]

Is there any update on this matter?

You wrote that there is currently only the CAAM based implementation.

I hope there's a way to implement encrypted boot using the various keys. Unfortunately, I don't have access to the SRM.