i.MX ProcessorsのトピックSecure boot for imx6dl on linux

Secure boot for imx6dl on linux

VishalRana118 — Fri, 07 Oct 2022 13:01:20 GMT

Hello Team,

I am working on adding Secure boot functionality for my sub system. Which developed on imx6Dl.

Linux kernel 4.1.15 Ver.

u-boot 2016.

I have downloaded CST-3.1.0.tgz tool from site.

By following release/doc/CST_UG and other readme files able to Generate key and cert.

Able to update ucl2 file in{ \deployment\Profiles\Linux\OS Firmware} directory to fuse the OTP registers.

able to write u-boot.csf file by referring above Doc. In u-boot.csf file in block section Iam putting the offset by running mkimage -l cmd on u-boot.imx

but unable to generate signed images for u-boot.imx, zImage, Rootfs.

Also I am using MfgTool2 for flashing the device which takes u-boot_mfg.imx and zImage_mfg may be these images also need to update.

If there is any reference document or guide then please share.

Regards,

Vishal Rana

Re: Secure boot for imx6dl on linux

VishalRana118 — Mon, 10 Oct 2022 06:05:21 GMT

Hi,

Getting below information after running mkimage -l.

this u-boot.imx image is generated by enabling the macro CONFIG_SECURE_BOOT in "include/configs/mx6sabre_common.h".

me@D-developer:~/Projects/uboot-imx/tools$ mkimage -l ../u-boot.imx
Image Type:   Freescale IMX Boot Image
Image Ver:    2 (i.MX53/6/7 compatible)
Mode:         DCD
Data Size:    307200 Bytes = 300.00 KiB = 0.29 MiB
Load Address: 177ff420
Entry Point:  17800000
HAB Blocks:   0x177ff400 0x00000000 0x00046c00
DCD Blocks:   0x00910000 0x0000002c 0x000002f0

using above info how below script should be modified.

///////////////////////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////////

#!/bin/sh
echo "Extend U-Boot to 0x2f000..."
objcopy -I binary -O binary --pad-to 0x2f000 --gap-fill=0xff U-Boot.bin UBoot-
pad.bin
echo "generate CSF data..."
../linux/cst --o U-Boot_CSF.bin < U-Boot.CSF
echo "merge image and CSF data..."
cat U-Boot-pad.bin U-Boot_CSF.bin > U-Boot-signed.bin
echo "extend final image to 0x31000..."
objcopy -I binary -O binary --pad-to 0x31000 --gap-fill=0xff U-Bootsigned.
bin U-Boot-signed-pad.bin
echo "U-Boot-signed-pad.bin is ready"

////////////////////////////////////////////////////////////////////////////////

Re: Secure boot for imx6dl on linux

VishalRana118 — Mon, 10 Oct 2022 15:27:26 GMT

Hi Team,

I am referring u-boot-imx/doc/README.imximage for how to prepare u-boot.imx signed image.

According to readme file I executed below steps to generate u-boot-signed.imx image.

But size of u-boot.imx and u-boot-signed.imx(final uboot signed image) remain same.

Is it expected?? How I can validate.

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

mkimage will output additional information about "HAB Blocks"
which can be used in the Freescale tooling to authenticate U-Boot
(entries in the CSF file).

Image Type:   Freescale IMX Boot Image
Image Ver:    2 (i.MX53/6 compatible)
Data Size:    307200 Bytes = 300.00 kB = 0.29 MB
Load Address: 177ff420
Entry Point:  17800000
HAB Blocks:   177ff400 00000000 00046c00{ these values I am getting for my u-boot.imx image}
          ^^^^^^^^ ^^^^^^^^ ^^^^^^^^
        |    |       |
        |    |       -------- (1)
        |    |
        |    ------------------- (2)
        |
        --------------------------- (3)

(1)    Size of area in file u-boot.imx to sign.This area should include the IVT, the Boot Data the DCD
    and U-Boot itself.
(2)    Start of area in u-boot.imx to sign
(3)    Start of area in RAM to authenticate

CONFIG_SECURE_BOOT currently enables only an additional command
'hab_status' in U-Boot to retrieve the HAB status and events. This
can be useful while developing and testing HAB.

Commands to generate a signed U-Boot using Freescale HAB tools:
cst --o U-Boot_CSF.bin < U-Boot.CSF

# padded value is 0x4000 in CONFIG_CSF_SIZE macro.
objcopy -I binary -O binary --pad-to 0x4000 --gap-fill=0x00 U-Boot_CSF.bin U-Boot_CSF_pad.bin
cat u-boot.imx U-Boot_CSF_pad.bin > u-boot-signed.imx

NOTE: U-Boot_CSF.bin needs to be padded to the value specified in the imximage.cfg file.

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Regards,

Vishal Rana

Re: Secure boot for imx6dl on linux

VishalRana118 — Mon, 10 Oct 2022 15:29:22 GMT

Hi Team,

I am referring u-boot-imx/doc/README.imximage for how to prepare u-boot.imx signed image.

According to readme file I executed below steps to generate u-boot-signed.imx image.

But size of u-boot.imx and u-boot-signed.imx(final uboot signed image) remain same.

Is it expected?? How I can validate.

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

mkimage will output additional information about "HAB Blocks"
which can be used in the Freescale tooling to authenticate U-Boot
(entries in the CSF file).

CONFIG_SECURE_BOOT currently enables only an additional command
'hab_status' in U-Boot to retrieve the HAB status and events. This
can be useful while developing and testing HAB.

Commands to generate a signed U-Boot using Freescale HAB tools:
cst --o U-Boot_CSF.bin < U-Boot.CSF

# padded value is 0x4000 in CONFIG_CSF_SIZE macro.
objcopy -I binary -O binary --pad-to 0x4000 --gap-fill=0x00 U-Boot_CSF.bin U-Boot_CSF_pad.bin
cat u-boot.imx U-Boot_CSF_pad.bin > u-boot-signed.imx

NOTE: U-Boot_CSF.bin needs to be padded to the value specified in the imximage.cfg file.

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Regards,

Vishal Rana

Re: Secure boot for imx6dl on linux

VishalRana118 — Mon, 10 Oct 2022 19:00:37 GMT

Hello Team,

I am not able to generate u-boot-signed.imx image.

By Running cst --o U-Boot_CSF.bin < U-boot.csf command leads to

error realloc(): invalid pointer, Aboard (core dumped)

I am attaching U-boot.txt (.csf) file for reference. Please help me to resolve it.

Regards,

Vishal Rana