Verify signed images from Linux user space

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Verify signed images from Linux user space

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jb2
Contributor I

Hello

I succeed to use the UBoot and kernel verification with the HAB API but I want to go further in sign verification.

I've two partitions and a mechanism to update the kernel (and rootfs) from the linux user space. What I want is to verify the authenticity of the kernel before burn it to the non-active partition.

The HAB API is in the boot ROM and, as far as I could find, it's not possible to use this API in the user space. Is it all right?

So I'm trying to do the verification my self:

- Read SRK in UBoot and transfer in the user space with the bootcmd

- Verify the two certificate with this SRK (CFS and IMG certificate)

- Verify the signature of the command and the kernel with openssl.

My questions are:

1) Do you think is it possible to verify the kernel in that way?

2) I don't know how to verify the CFS/IMG certificate 

3) The signature check failed with open SSL. Here are information:

      ivt.bin: interrupt vector for kernel

      linux.csf: csf file for kernel

      test_signature.sh: script to check the signature of the kernel image

            In code file I've: from 0x0 (beginning of the kernel to the end of IVT)

            Signature is the signature after IMG1_cert

            Certificate is the IMG1_ certificate

            response: "Verification Failure"

Thank you

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1 Reply

206 Views
Yuri
NXP TechSupport
NXP TechSupport

Hello,

 

  We recommend to use the DM-crypt after U-boot and kernel are verified.

Use  app note  AN12714  (i.MX Encrypted Storage Using CAAM Secure Keys)

https://www.nxp.com/docs/en/application-note/AN12714.pdf 

 

Have a great day,

Yuri.

 

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