From: Breno Lima breno.lima@nxp.com
The README.mxc_hab is outdated and need improvements, add the following modifications:
- Reorganize document and remove duplicate content - Add CST download link - Update CST package name - Align command lines with CST v2.3.3 - Update U-Boot binary name - Remove CSF padding since is not documented in AN4581
Signed-off-by: Breno Lima breno.lima@nxp.com --- doc/README.mxc_hab | 72 +++++++++++++++++++++++++----------------------------- 1 file changed, 33 insertions(+), 39 deletions(-)
diff --git a/doc/README.mxc_hab b/doc/README.mxc_hab index 056ade7..75390a5 100644 --- a/doc/README.mxc_hab +++ b/doc/README.mxc_hab @@ -11,14 +11,22 @@ In addition, the U-Boot image to be programmed into the boot media needs to be properly constructed, i.e. it must contain a proper Command Sequence File (CSF).
-The Initial Vector Table contains a pointer to the CSF. Please see -doc/README.imximage for how to prepare u-boot.imx. +The CSF itself is generated by the i.MX High Assurance Boot Reference +Code Signing Tool. +https://www.nxp.com/webapp/sps/download/license.jsp?colCode=IMX_CST_TOOL
-The CSF itself is being generated by Freescale HAB tools. +More information about the CSF and HAB can be found in the AN4581. +https://www.nxp.com/docs/en/application-note/AN4581.pdf + +We don't want to explain how to create a PKI tree or SRK table as +this is well explained in the Application Note.
-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). +2. Secure Boot on non-SPL targets +--------------------------------- + +On non-SPL targets a singe U-Boot binary is generated, mkimage will +output additional information about "HAB Blocks" which can be used +in the CST to authenticate the U-Boot image (entries in the CSF file).
Image Type: Freescale IMX Boot Image Image Ver: 2 (i.MX53/6 compatible) @@ -34,46 +42,35 @@ HAB Blocks: 177ff400 00000000 0004dc00 | --------------------------- (3)
-(1) Size of area in file u-boot.imx to sign +(1) Size of area in file u-boot-dtb.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 +(2) Start of area in u-boot-dtb.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 -objcopy -I binary -O binary --pad-to 0x2000 --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. - +Commands to generate a signed U-Boot using i.MX HAB CST tool: +# Compile CSF and create signature +cst --o csf-u-boot.bin --i command_sequence_uboot.csf +# Append compiled CSF to Binary +cat u-boot-dtb.imx csf-u-boot.bin > u-boot-signed.imx
-2. Using Secure Boot on i.MX6 machines with SPL support -------------------------------------------------------- +3. Secure Boot on SPL targets +-----------------------------
This version of U-Boot is able to build a signable version of the SPL as well as a signable version of the U-Boot image. The signature can be verified through High Assurance Boot (HAB).
-CONFIG_SECURE_BOOT is needed to build those two binaries. After building, you need to create a command sequence file and use -Freescales Code Signing Tool to sign both binaries. After creation, +i.MX HAB Code Signing Tool to sign both binaries. After creation, the mkimage tool outputs the required information about the HAB Blocks parameter for the CSF. During the build, the information is preserved in log files named as the binaries. (SPL.log and u-boot-ivt.log).
-More information about the CSF and HAB can be found in the AN4581. -https://cache.freescale.com/files/32bit/doc/app_note/AN4581.pdf - -We don't want to explain how to create a PKI tree or SRK table as -this is well explained in the Application Note. - Example Output of the SPL (imximage) creation: Image Type: Freescale IMX Boot Image Image Ver: 2 (i.MX53/6/7 compatible) @@ -92,23 +89,22 @@ Example Output of the u-boot-ivt.img (firmware_ivt) creation: Entry Point: 00000000 HAB Blocks: 0x177fffc0 0x0000 0x00054020
-The CST (Code Signing Tool) can be downloaded from NXP. # Compile CSF and create signature -./cst --o csf-u-boot.bin < command_sequence_uboot.csf -./cst --o csf-SPL.bin < command_sequence_spl.csf +cst --o csf-u-boot.bin --i command_sequence_uboot.csf +cst --o csf-SPL.bin --i command_sequence_spl.csf # Append compiled CSF to Binary cat SPL csf-SPL.bin > SPL-signed cat u-boot-ivt.img csf-u-boot.bin > u-boot-signed.img
-These two signed binaries can be used on an i.MX6 in closed +These two signed binaries can be used on an i.MX in closed configuration when the according SRK Table Hash has been flashed.
-3. Setup U-Boot Image for Encrypted Boot ------------------------------------------ +4. Setup U-Boot Image for Encrypted Boot +---------------------------------------- An authenticated U-Boot image is used as starting point for -Encrypted Boot. The image is encrypted by Freescale's Code -Signing Tool (CST). The CST replaces only the image data of -u-boot.imx with the encrypted data. The Initial Vector Table, +Encrypted Boot. The image is encrypted by i.MX Code Signing +Tool (CST). The CST replaces only the image data of +u-boot-dtb.imx with the encrypted data. The Initial Vector Table, DCD, and Boot data, remains in plaintext.
The image data is encrypted with a Encryption Key (DEK). @@ -138,9 +134,7 @@ U-Boot image. Note that the blob needs to be transferred back to the host.Then the following commands are used to construct the final image.
-objcopy -I binary -O binary --pad-to 0x2000 --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 +cat u-boot-dtb.imx csf-u-boot.bin > u-boot-signed.imx objcopy -I binary -O binary --pad-to <blob_dst> --gap-fill=0x00 \ u-boot-signed.imx u-boot-signed-pad.bin cat u-boot-signed-pad.imx DEK_blob.bin > u-boot-encrypted.imx