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Commit 4886ec745e0ac8c38f2d61546eebca8cd0dfeb17

Authored by Breno Lima
Committed by Ye Li
1 parent e7e56da835
Exists in smarc_8mm-imx_v2019.04_4.19.35_1.1.0 and in 1 other branch smarc_8m-imx_v2019.04_4.19.35_1.1.0

MLK-22570-2 doc: habv4: Add encrypted boot documentation for i.MX8M, i.MX8MM and i.MX8MN devices 

Add HABv4 encrypted boot documentation for i.MX8M, i.MX8MM and i.MX8MN
family devices covering the following topics:

- How to encrypt and sign a flash.bin image.
- How to manage CAAM PRIBLOBs when using encrypted boot
- Add 4 CSF examples.

Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Marius Grigoras <marius.grigoras@nxp.com>
Signed-off-by: Breno Lima <breno.lima@nxp.com>
(cherry picked from commit eee57255e0b0ea3a2808d3a2c19c8685afbac39b)

Showing 5 changed files with 700 additions and 0 deletions Side-by-side Diff

doc/imx/habv4/csf_examples/mx8m_mx8mm/csf_fit_enc.txt
Diff comments   View file @ 4886ec7
  1 +[Header]
  2 + Version = 4.3
  3 + Hash Algorithm = sha256
  4 + Engine = CAAM
  5 + Engine Configuration = 0
  6 + Certificate Format = X509
  7 + Signature Format = CMS
  8 +
  9 +[Install SRK]
  10 + File = "../crts/SRK_1_2_3_4_table.bin"
  11 + Source index = 0
  12 +
  13 +[Install CSFK]
  14 + File = "../crts/CSF1_1_sha256_2048_65537_v3_usr_crt.pem"
  15 +
  16 +[Authenticate CSF]
  17 +
  18 +[Unlock]
  19 + Engine = CAAM
  20 + Features = MID
  21 +
  22 +[Install Key]
  23 + Verification index = 0
  24 + Target index = 2
  25 + File = "../crts/IMG1_1_sha256_2048_65537_v3_usr_crt.pem"
  26 +
  27 +[Authenticate Data]
  28 + Verification index = 2
  29 + Blocks = 0x401fcdc0 0x57c00 0x1020 "flash-spl-enc.bin"
  30 +
  31 +[Install Secret Key]
  32 + # Install the blob
  33 + Verification Index = 0
  34 + Target Index = 0
  35 + Key = "dek_fit.bin"
  36 + Key Length = 128
  37 + # Fixed address defined in imx-mkimage project in iMX8M/soc.mak file
  38 + # DEK_BLOB_LOAD_ADDR = 0x40400000
  39 + Blob Address = 0x40400000
  40 +
  41 +[Decrypt Data]
  42 + # The decrypt data command below causes CST to modify the input
  43 + # file and encrypt the specified block of data. This image file
  44 + # is a copy of the file used for the authentication command above
  45 + Verification Index = 0
  46 + Mac Bytes = 16
  47 + Blocks = 0x40200000 0x5AC00 0xB8940 "flash-spl-fit-enc.bin", \
  48 + 0x920000 0x113540 0xA160 "flash-spl-fit-enc.bin", \
  49 + 0xBE000000 0x11D6A0 0x48520 "flash-spl-fit-enc.bin"
doc/imx/habv4/csf_examples/mx8m_mx8mm/csf_fit_sign_enc.txt
Diff comments   View file @ 4886ec7
  1 +[Header]
  2 + Version = 4.3
  3 + Hash Algorithm = sha256
  4 + Engine = CAAM
  5 + Engine Configuration = 0
  6 + Certificate Format = X509
  7 + Signature Format = CMS
  8 +
  9 +[Install SRK]
  10 + File = "../crts/SRK_1_2_3_4_table.bin"
  11 + Source index = 0
  12 +
  13 +[Install CSFK]
  14 + File = "../crts/CSF1_1_sha256_2048_65537_v3_usr_crt.pem"
  15 +
  16 +[Authenticate CSF]
  17 +
  18 +[Unlock]
  19 + Engine = CAAM
  20 + Features = MID
  21 +
  22 +[Install Key]
  23 + Verification index = 0
  24 + Target index = 2
  25 + File = "../crts/IMG1_1_sha256_2048_65537_v3_usr_crt.pem"
  26 +
  27 +[Authenticate Data]
  28 + Verification index = 2
  29 + Blocks = 0x401fcdc0 0x57c00 0x1020 "flash-spl-fit-enc.bin", \
  30 + 0x40200000 0x5AC00 0xB8940 "flash-spl-fit-enc.bin", \
  31 + 0x920000 0x113540 0xA160 "flash-spl-fit-enc.bin", \
  32 + 0xBE000000 0x11D6A0 0x48520 "flash-spl-fit-enc.bin"
  33 +
  34 +[Install Secret Key]
  35 + # Install the blob
  36 + Verification Index = 0
  37 + Target Index = 0
  38 + Key = "dek_fit_dummy.bin"
  39 + Key Length = 128
  40 + # Fixed address defined in imx-mkimage project in iMX8M/soc.mak file
  41 + # DEK_BLOB_LOAD_ADDR = 0x40400000
  42 + Blob Address = 0x40400000
  43 +
  44 +[Decrypt Data]
  45 + # The decrypt data command below causes CST to modify the input
  46 + # file and encrypt the specified block of data. This image file
  47 + # is a copy of the file used for the authentication command above
  48 + Verification Index = 0
  49 + Mac Bytes = 16
  50 + Blocks = 0x40200000 0x5AC00 0xB8940 "flash-spl-fit-enc-dummy.bin", \
  51 + 0x920000 0x113540 0xA160 "flash-spl-fit-enc-dummy.bin", \
  52 + 0xBE000000 0x11D6A0 0x48520 "flash-spl-fit-enc-dummy.bin"
doc/imx/habv4/csf_examples/mx8m_mx8mm/csf_spl_enc.txt
Diff comments   View file @ 4886ec7
  1 +[Header]
  2 + Version = 4.3
  3 + Hash Algorithm = sha256
  4 + Engine = CAAM
  5 + Engine Configuration = 0
  6 + Certificate Format = X509
  7 + Signature Format = CMS
  8 +
  9 +[Install SRK]
  10 + File = "../crts/SRK_1_2_3_4_table.bin"
  11 + Source index = 0
  12 +
  13 +[Install CSFK]
  14 + File = "../crts/CSF1_1_sha256_2048_65537_v3_usr_crt.pem"
  15 +
  16 +[Authenticate CSF]
  17 +
  18 +[Unlock]
  19 + Engine = CAAM
  20 + Features = MID
  21 +
  22 +[Install Key]
  23 + Verification index = 0
  24 + Target index = 2
  25 + File = "../crts/IMG1_1_sha256_2048_65537_v3_usr_crt.pem"
  26 +
  27 +[Authenticate Data]
  28 + Verification index = 2
  29 + Blocks = 0x7e0fc0 0x0 0x40 "flash.bin"
  30 +
  31 +[Install Secret Key]
  32 + # Install the blob
  33 + Verification Index = 0
  34 + Target Index = 0
  35 + Key = "dek_spl.bin"
  36 + Key Length = 128
  37 + # Authenticate Start Address + SPL & DDR FW image length + CSF Padding
  38 + # 0x7E0FC0 + 0x2c400 + 0x2000
  39 + Blob Address = 0x80F3C0
  40 +
  41 +[Decrypt Data]
  42 + # The decrypt data command below causes CST to modify the input
  43 + # file and encrypt the specified block of data. This image file
  44 + # is a copy of the file used for the authentication command above
  45 + Verification Index = 0
  46 + Mac Bytes = 16
  47 + # Start Address = Start Address + SPL header = 0x7E0FC0 + 0x40 = 0x7E1000
  48 + # Offset = Image offset (image_off) = 0x40
  49 + # Decrypt size = Image length - SPL header = 0x2c400 - 0x40 = 0x2C3C0
  50 + Blocks = 0x7E1000 0x40 0x2C3C0 "flash-spl-enc.bin"
doc/imx/habv4/csf_examples/mx8m_mx8mm/csf_spl_sign_enc.txt
Diff comments   View file @ 4886ec7
  1 +[Header]
  2 + Version = 4.3
  3 + Hash Algorithm = sha256
  4 + Engine = CAAM
  5 + Engine Configuration = 0
  6 + Certificate Format = X509
  7 + Signature Format = CMS
  8 +
  9 +[Install SRK]
  10 + File = "../crts/SRK_1_2_3_4_table.bin"
  11 + Source index = 0
  12 +
  13 +[Install CSFK]
  14 + File = "../crts/CSF1_1_sha256_2048_65537_v3_usr_crt.pem"
  15 +
  16 +[Authenticate CSF]
  17 +
  18 +[Unlock]
  19 + Engine = CAAM
  20 + Features = MID
  21 +
  22 +[Install Key]
  23 + Verification index = 0
  24 + Target index = 2
  25 + File = "../crts/IMG1_1_sha256_2048_65537_v3_usr_crt.pem"
  26 +
  27 +[Authenticate Data]
  28 + Verification index = 2
  29 + Blocks = 0x7E0FC0 0x0 0x2C400 "flash-spl-enc.bin"
  30 +
  31 +[Install Secret Key]
  32 + # Install the blob
  33 + Verification Index = 0
  34 + Target Index = 0
  35 + Key = "dek_spl_dummy.bin"
  36 + Key Length = 128
  37 + # Authenticate Start Address + Image length + CSF Padding
  38 + # 0x7E0FC0 + 0x2c400 + 0x2000
  39 + Blob Address = 0x80F3C0
  40 +
  41 +[Decrypt Data]
  42 + # The decrypt data command below causes CST to modify the input
  43 + # file and encrypt the specified block of data. This image file
  44 + # is a copy of the file used for the authentication command above
  45 + Verification Index = 0
  46 + Mac Bytes = 16
  47 + Blocks = 0x7E1000 0x40 0x2C3C0 "flash-spl-enc-dummy.bin"
doc/imx/habv4/guides/mx8m_mx8mm_encrypted_boot.txt
Diff comments   View file @ 4886ec7
  1 + +======================================================+
  2 + + i.MX8M, i.MX8MM Encrypted Boot guide using HABv4 +
  3 + +======================================================+
  4 +
  5 +1. HABv4 Encrypted Boot process
  6 +-------------------------------
  7 +
  8 +This document describes a step-by-step procedure on how to encrypt and sign a
  9 +bootloader image for i.MX8M, i.MX8MM, i.MX8MN family devices. It is assumed
  10 +that the reader is familiar with basic HAB concepts and has already closed
  11 +the device, step-by-step procedure can be found in mx8m_mx8mm_secure_boot.txt
  12 +guide.
  13 +
  14 +Details about encrypted boot can be found in application note AN12056[1] and
  15 +in the introduction_habv4.txt document.
  16 +
  17 +The steps described in this document were based in i.MX8MM device, the same
  18 +concept can be applied to i.MX8M and i.MX8MN family devices.
  19 +
  20 +1.1 Understanding the encrypted flash.bin image layout
  21 +------------------------------------------------------
  22 +
  23 +As described in mx8m_mx8mm_secure_boot.txt guide a single binary is used
  24 +to boot the device, the imx-mkimage tool combines all the input images in
  25 +a FIT structure, generating a flash.bin binary.
  26 +
  27 +The encrypted boot image requires a DEK (Data Encryption Key) blob on each time
  28 +HABv4 is used to decrypt an image. The DEK blob is used as a security layer to
  29 +wrap and store the DEK off-chip using the OTPMK which is unique per device.
  30 +More details can be found in AN12056 application note.
  31 +
  32 +The diagram below illustrates an encrypted flash.bin image layout:
  33 +
  34 + +-----------------------------+
  35 + | |
  36 + | *Signed HDMI/DP FW |
  37 + | |
  38 + +-----------------------------+
  39 + | Padding |
  40 + ------------------ +-----------------------------+ --------
  41 + ^ | IVT - SPL | ^
  42 + Signed | ------- +-----------------------------+ |
  43 + Data | Enc ^ | u-boot-spl.bin | |
  44 + | Data | | + | | SPL
  45 + v v | DDR FW | | Image
  46 + ------------------ +-----------------------------+ |
  47 + | CSF - SPL + DDR FW | v
  48 + +-----------------------------+ --------
  49 + | DEK Blob |
  50 + +-----------------------------+
  51 + | Padding |
  52 + ------- +-----------------------------+ --------
  53 + Signed ^ | FDT - FIT | ^
  54 + Data | +-----------------------------+ |
  55 + v | IVT - FIT | |
  56 + ------- +-----------------------------+ |
  57 + | CSF - FIT | |
  58 + ------------------ +-----------------------------+ |
  59 + ^ | u-boot-nodtb.bin | | FIT
  60 + | +-----------------------------+ | Image
  61 + Signed and | | u-boot.dtb | |
  62 + Encrypted | +-----------------------------+ |
  63 + Data | | bl31.bin (ATF) | |
  64 + | +-----------------------------+ |
  65 + v | OP-TEE | |
  66 + ------------------ +-----------------------------+ |
  67 + | DEK Blob | v
  68 + +-----------------------------+ --------
  69 + * Only supported on i.MX8M series
  70 +
  71 +1.2 Enabling the encrypted boot support in U-Boot
  72 +--------------------------------------------------
  73 +
  74 +For deploying an encrypted boot image additional U-Boot tools are needed,
  75 +please be sure to have the following features enabled, this can be achieved
  76 +by following one of the methods below:
  77 +
  78 +- Defconfig
  79 +
  80 + CONFIG_SECURE_BOOT=y
  81 + CONFIG_FAT_WRITE=y
  82 + CONFIG_CMD_DEKBLOB=y
  83 + CONFIG_IMX_OPTEE_DEK_ENCAP=y
  84 + CONFIG_CMD_PRIBLOB=y
  85 +
  86 +- Kconfig
  87 +
  88 + ARM architecture -> Support i.MX HAB features
  89 + ARM architecture -> Support the 'dek_blob' command
  90 + ARM architecture -> Support the set_priblob_bitfield command
  91 + File systems -> Enable FAT filesystem support-> Enable FAT filesystem
  92 + write support
  93 +
  94 +1.3 Enabling the encrypted boot support in CST
  95 +-----------------------------------------------
  96 +
  97 +The encryption feature is not enabled by default in Code Signing tools (CST).
  98 +The CST backend must be recompiled, execute the following commands to enable
  99 +encryption support in CST:
  100 +
  101 + $ sudo apt-get install libssl-dev openssl
  102 + $ cd <CST install directory>/code/back_end/src
  103 + $ gcc -o cst_encrypted -I ../hdr -L ../../../linux64/lib *.c
  104 + -lfrontend -lcrypto
  105 + $ cp cst_encrypted ../../../linux64/bin/
  106 +
  107 +1.4 Building OP-TEE and ATF to support DEK blob tool
  108 +-----------------------------------------------------
  109 +
  110 +The DEK blob must be created by a software running in Arm TrustZone Secure
  111 +World, the CAAM block takes into consideration the TrustZone configuration
  112 +when encapsulating the DEK and the resulting blob can be only decapsulated
  113 +by a SW running in the same configuration. As ROM code is running in ARM
  114 +TrustZone secure world we must encapsulate the blobs using OP-TEE.
  115 +
  116 +- Building ATF to support OP-TEE:
  117 +
  118 + $ make PLAT=<SoC Name> SPD=opteed bl31
  119 +
  120 +- Building OP-TEE to support DEK blob encapsulation:
  121 +
  122 + $ CFG_NXPCRYPT=y CFG_GEN_DEK_BLOB=y source ./scripts/nxp_build.sh <Board Name>
  123 +
  124 +* OP-TEE debug logs can be enabled by adding CFG_TEE_CORE_LOG_LEVEL=4 in
  125 + command line above.
  126 +
  127 +1.5 Preparing the fit image
  128 +----------------------------
  129 +
  130 +As explained in mx8m_mx8mm_secure_boot.txt document the imx-mkimage project is
  131 +used to combine all the images in a single flash.bin binary.
  132 +
  133 +Copy all the binaries generated (U-Boot images, bl31.bin, tee.bin and Firmware)
  134 +into iMX8M directory and run the following commands according to the target
  135 +device:
  136 +
  137 +- Create a dummy DEK blob:
  138 +
  139 + $ dd if=/dev/zero of=iMX8M/dek_blob_fit_dummy.bin bs=96 count=1 && sync
  140 +
  141 +- Assembly flash.bin binary:
  142 +
  143 + $ make SOC=<SoC Name> flash_spl_uboot
  144 +
  145 +The mkimage log will be used during the encrypted boot procedure to create the
  146 +Command Sequence File (CSF):
  147 +
  148 +- imx-mkimage build log:
  149 +
  150 + Loader IMAGE:
  151 + header_image_off 0x0
  152 + dcd_off 0x0
  153 + image_off 0x40
  154 + csf_off 0x2c400
  155 + spl hab block: 0x7e0fc0 0x0 0x2c400
  156 +
  157 + Second Loader IMAGE:
  158 + sld_header_off 0x57c00
  159 + sld_csf_off 0x58c20
  160 + sld hab block: 0x401fcdc0 0x57c00 0x1020
  161 +
  162 +- Additional HAB information is provided by running the following command:
  163 +
  164 + $ make SOC=<SoC Name> print_fit_hab
  165 +
  166 + ./../scripts/pad_image.sh bl31.bin
  167 + ./../scripts/pad_image.sh u-boot-nodtb.bin fsl-imx8mm-evk.dtb
  168 + TEE_LOAD_ADDR=0xbe000000 ATF_LOAD_ADDR=0x00920000 VERSION=v1 \
  169 + ./print_fit_hab.sh 0x60000 fsl-imx8mm-evk.dtb
  170 + 0x40200000 0x5AC00 0xB0318
  171 + 0x402B0318 0x10AF18 0x8628
  172 + 0x920000 0x113540 0xA160
  173 + 0xBE000000 0x11D6A0 0x48520
  174 +
  175 +1.6 Creating the CSF description file for SPL + DDR FW image
  176 +-------------------------------------------------------------
  177 +
  178 +The CSF contains all the commands that the ROM executes during the secure boot.
  179 +These commands instruct the HAB on which memory areas of the image to
  180 +authenticate and/or decrypt, which keys to install, use, etc...
  181 +
  182 +CSF examples for encrypted boot are available under
  183 +doc/imx/hab/habv4/csf_examples/ directory.
  184 +
  185 +With current CST implementation is not possible to encrypt and sign an image
  186 +at the same time, hence two CSF files are required on each time HAB is used.
  187 +
  188 +1.6.1 csf_spl_enc.txt
  189 +----------------------
  190 +
  191 +The first CSF is used to encrypt the SPL and DDR FW images and generate the
  192 +dek_spl.bin file. The Authenticate Data command has to cover only the image
  193 +header and two commands have to be added to encrypt the image.
  194 +
  195 +- Add the Authenticate Data command to only cover SPL IVT and boot data:
  196 +
  197 + Blocks = 0x7E0FC0 0x0 0x40 "flash.bin"
  198 +
  199 +- Add the Install Secret Key command to generate the dek_spl.bin file and
  200 + install the blob. The Blob Address depends on your image layout and can
  201 + be calculated as following:
  202 +
  203 + Key = "dek_spl.bin"
  204 + Blob Address = Authenticate Start Address + Image length + CSF Padding
  205 + = 0x7E0FC0 + 0x2c400 + 0x2000 = 0x80F3C0
  206 +
  207 +- Add the Decrypt Data command to encrypt the file. As SPL image header
  208 + cannot be encrypted we need to calculate the Block as following:
  209 +
  210 + Start Address = Start Address + SPL header = 0x7E0FC0 + 0x40 = 0x7E1000
  211 + Offset = Image offset (image_off) = 0x40
  212 + Decrypt size = Image length - SPL header = 0x2C400 - 0x40 = 0x2C3C0
  213 +
  214 + Blocks = 0x7E1000 0x40 0x2C3C0 "flash-spl-enc.bin"
  215 +
  216 +1.6.2 csf_spl_sign_enc.txt
  217 +---------------------------
  218 +
  219 +The second CSF is used to sign the encrypted SPL image previously generated
  220 +(flash-spl-enc.bin).
  221 +
  222 +- The Authenticate Data command should cover the entire SPL and DDR FW image,
  223 + the file parameter is the encrypted image flash-spl-enc.bin:
  224 +
  225 + Blocks = 0x7E0FC0 0x0 0x2C400 "flash-spl-enc.bin"
  226 +
  227 +- Add the Install Secret Key command to generate a dummy DEK blob file,
  228 + the blob address should be the same as used in csf_spl_enc.txt:
  229 +
  230 + Key = "dek_spl_dummy.bin"
  231 +
  232 +- Add the Decrypt Data command to encrypt the file. As image was encrypted
  233 + in CSF above we need to encrypt a dummy file, the block addresses should be
  234 + the same as used in csf_spl_enc.txt:
  235 +
  236 + Blocks = 0x7E1000 0x40 0x2C3C0 "flash-spl-enc-dummy.bin"
  237 +
  238 +1.7 Encrypting and signing the SPL + DDR FW image
  239 +--------------------------------------------------
  240 +
  241 +The CST is used to encrypt the image and regenerate a random DEK. During this
  242 +step two CSF binaries are generated but only one will be included in final
  243 +image.
  244 +
  245 +- Encrypt the SPL + DDR FW image:
  246 +
  247 + $ cp flash.bin flash-spl-enc.bin
  248 + $ ./cst_encrypted -i csf_spl_enc.txt -o csf_spl_enc.bin
  249 +
  250 +- Sign the encrypted SPL + DDR FW image:
  251 +
  252 + $ cp flash-spl-enc.bin flash-spl-enc-dummy.bin
  253 + $ ./cst_encrypted -i csf_spl_sign_enc.txt -o csf_spl_sign_enc.bin
  254 +
  255 +1.7.1 Create final CSF binary for SPL + DDR FW image
  256 +-----------------------------------------------------
  257 +
  258 +As only one CSF binary will be included in final image it's necessary to
  259 +swap Nonce/MAC from csf_spl_enc.bin to csf_spl_sign_enc.bin.
  260 +
  261 +- Calculate Nonce/MAC size based on MAC bytes value in CSF:
  262 +
  263 + Nonce/MAC size = Nonce size + MAC bytes + CSF header for Nonce/Mac
  264 + = 12 + 16 + 8 = 36 bytes
  265 +
  266 +- Calculate Nonce/MAC offset in CSF:
  267 +
  268 + MAC offset = csf_spl_enc.bin size - Nonce/MAC size
  269 + = 3980 - 36 = 3944 Bytes
  270 +
  271 +- Extract Nonce/MAC from csf_spl_enc.bin:
  272 +
  273 + $ dd if=csf_spl_enc.bin of=noncemac.bin bs=1 skip=3944 count=36
  274 +
  275 +- Replace the MAC of csf_spl_sign_enc with the one extracted above:
  276 +
  277 + $ dd if=noncemac.bin of=csf_spl_sign_enc.bin bs=1 seek=3944 count=36
  278 +
  279 +1.8 Creating the CSF description file for FIT image
  280 +----------------------------------------------------
  281 +
  282 +Similar to SPL image two CSF files are required encrypt and sign the FIT
  283 +image.
  284 +
  285 +Please note that the steps below are using the flash-spl-enc.bin image created
  286 +in steps above.
  287 +
  288 +1.8.1 csf_fit_enc.txt
  289 +----------------------
  290 +
  291 +The first CSF is used to encrypt the FIT image and generate the dek_fit.bin
  292 +file.
  293 +
  294 +- Modify the Authenticate Data command to only cover FIT image FDT header:
  295 +
  296 + Blocks = 0x401FCDC0 0x57C00 0x1020 "flash-spl-enc.bin"
  297 +
  298 +- Add the Install Secret Key command to generate the dek_fit.bin file and
  299 + install the blob. The Blob Address is a fixed address defined in imx-mkimage
  300 + project in iMX8M/soc.mak file:
  301 +
  302 + iMX8M/soc.mak:
  303 + DEK_BLOB_LOAD_ADDR = 0x40400000
  304 +
  305 + Key = "dek_fit.bin"
  306 + Blob Address = 0x40400000
  307 +
  308 +- Add the Decrypt Data command to encrypt the file.
  309 +
  310 + The CST can only encrypt images that are 16 bytes aligned, as u-boot-nodtb.bin
  311 + and u-boot.dtb are together 16 bytes aligned we should consider the first two
  312 + lines provided in print_fit_hab as a single block.
  313 +
  314 + imx-mkimage output:
  315 +
  316 + 0x40200000 0x5AC00 0xB0318 ──┬── Total length = 0xB0318 + 0x8628 = 0xB8940
  317 + 0x402B0318 0x10AF18 0x8628 ──┘
  318 + 0x920000 0x113540 0xA160
  319 + 0xBE000000 0x11D6A0 0x48520
  320 +
  321 + Decrypt data in csf_fit_enc.txt:
  322 +
  323 + Blocks = 0x40200000 0x5AC00 0xB8940 "flash-spl-fit-enc.bin", \
  324 + 0x920000 0x113540 0xA160 "flash-spl-fit-enc.bin", \
  325 + 0xBE000000 0x11D6A0 0x48520 "flash-spl-fit-enc.bin"
  326 +
  327 +1.8.2 csf_fit_sign_enc.txt
  328 +---------------------------
  329 +
  330 +The second CSF is used to sign the encrypted FIT image previously generated
  331 +(flash-spl-fit-enc.bin).
  332 +
  333 +- The Authenticate Data command should cover the entire FIT image,
  334 + the file parameter is the encrypted FIT image flash-spl-fit-enc.bin:
  335 +
  336 + Blocks = 0x401fcdc0 0x57c00 0x1020 "flash-spl-fit-enc.bin"
  337 + 0x40200000 0x5AC00 0xB8940 "flash-spl-fit-enc.bin", \
  338 + 0x920000 0x113540 0xA160 "flash-spl-fit-enc.bin", \
  339 + 0xBE000000 0x11D6A0 0x48520 "flash-spl-fit-enc.bin"
  340 +
  341 +
  342 +- Add the Install Secret Key command to generate a dummy DEK blob file,
  343 + the blob address should be the same as used in csf_spl_enc.txt:
  344 +
  345 + Key = "dek_fit_dummy.bin"
  346 +
  347 +- Add the Decrypt Data command to encrypt the file. As image was encrypted
  348 + in CSF above we need to encrypt a dummy file, the block address should be
  349 + the same as used in csf_spl_enc.txt:
  350 +
  351 + Blocks = 0x40200000 0x5AC00 0xB8940 "flash-spl-fit-enc-dummy.bin", \
  352 + 0x920000 0x113540 0xA160"flash-spl-fit-enc-dummy.bin", \
  353 + 0xBE000000 0x11D6A0 0x48520 "flash-spl-fit-enc-dummy.bin"
  354 +
  355 +1.9 Encrypting and signing the FIT image
  356 +-----------------------------------------
  357 +
  358 +The CST is used to encrypt the image and regenerate a random DEK. During this
  359 +step two CSF binaries are generated but only one will be included in final
  360 +image.
  361 +
  362 +- Encrypt the FIT image:
  363 +
  364 + $ cp flash-spl-enc.bin flash-spl-fit-enc.bin
  365 + $ ./cst_encrypted -i csf_fit_enc.txt -o csf_fit_enc.bin
  366 +
  367 +- Sign the encrypted FIT image:
  368 +
  369 + $ cp flash-spl-fit-enc.bin flash-spl-fit-enc-dummy.bin
  370 + $ ./cst_encrypted -i csf_fit_sign_enc.txt -o csf_fit_sign_enc.bin
  371 +
  372 +1.9.1 Create final CSF binary for FIT image
  373 +-----------------------------------------------------
  374 +
  375 +As only one CSF binary will be included in final image it's necessary to swap
  376 +Nonce/MAC from csf_fit_enc.bin to csf_fit_sign_enc.bin.
  377 +
  378 +- Calculate Nonce/MAC size based on MAC bytes value in CSF:
  379 +
  380 + Nonce/MAC size = Nonce size + MAC bytes + CSF header for Nonce/Mac
  381 + = 12 + 16 + 8 = 36 bytes
  382 +
  383 +- Calculate Nonce/MAC offset in csf_fit_enc.bin:
  384 +
  385 + MAC offset = csf_fit_enc.bin size - Nonce/MAC size
  386 + = 3996 - 36 = 3960 Bytes
  387 +
  388 +- Extract Nonce/MAC from csf_fit_enc.bin:
  389 +
  390 + $ dd if=csf_fit_enc.bin of=noncemac.bin bs=1 skip=3960 count=36
  391 +
  392 +- Calculate Nonce/MAC offset in csf_fit_sign_enc.bin:
  393 +
  394 + MAC offset = csf_fit_enc.bin size - Nonce/MAC size
  395 + = 4020 - 36 = 3984 Bytes
  396 +
  397 +- Replace the MAC of csf_fit_sign_enc.bin with the one extracted above:
  398 +
  399 + $ dd if=noncemac.bin of=csf_fit_sign_enc.bin bs=1 seek=3984 count=36
  400 +
  401 +1.10 Generate the DEK Blob
  402 +---------------------------
  403 +
  404 +The DEK must be encapsulated into a CAAM blob so it can be included into
  405 +the final encrypted binary. The U-Boot provides a tool called dek_blob
  406 +which is calling the CAAM implementation included in OP-TEE.
  407 +
  408 +Copy the dek_spl.bin and dek_fit.bin in SDCard FAT partition and run
  409 +the following commands from U-Boot prompt:
  410 +
  411 + => mmc list
  412 + FSL_SDHC: 1 (SD)
  413 + FSL_SDHC: 2
  414 + => fatload mmc 1:1 0x40400000 dek_spl.bin
  415 + => dek_blob 0x40400000 0x40401000 128
  416 + => fatwrite mmc 1:1 0x40401000 dek_spl_blob.bin 0x48
  417 + => fatload mmc 1:1 0x40402000 dek_fit.bin
  418 + => dek_blob 0x40402000 0x40403000 128
  419 + => fatwrite mmc 1:1 0x40403000 dek_fit_blob.bin 0x48
  420 +
  421 +In host PC copy the generated dek_spl_blob.bin and dek_fit_blob.bin to the
  422 +CST directory.
  423 +
  424 +1.11 Assembly the encrypted image
  425 +----------------------------------
  426 +
  427 +The CSF binaries generated in the steps above have to be inserted into the
  428 +encrypted image.
  429 +
  430 +The CSF offsets can be obtained from the flash.bin build log:
  431 +
  432 +- SPL CSF offset:
  433 +
  434 + csf_off 0x2c400
  435 +
  436 +- FIT CSF offset:
  437 +
  438 + sld_csf_off 0x58c20
  439 +
  440 +The encrypted flash.bin image can be then assembled:
  441 +
  442 +- Create a flash-spl-fit-enc.bin copy:
  443 +
  444 + $ cp flash-spl-fit-enc.bin encrypted-flash.bin
  445 +
  446 +1.11.1 Insert SPL CSF and DEK blob
  447 +-----------------------------------
  448 +
  449 +- Insert csf_spl_sign_enc.bin in encrypted-flash.bin at 0x2c400 offset:
  450 +
  451 + $ dd if=csf_spl_sign_enc.bin of=encrypted-flash.bin seek=$((0x2c400)) bs=1 conv=notrunc
  452 +
  453 +- Insert dek_spl_blob.bin in encrypted-flash.bin at 0x2c400 + 0x2000 offset:
  454 +
  455 + $ dd if=dek_spl_blob.bin of=encrypted-flash.bin seek=$((0x2e400)) bs=1 conv=notrunc
  456 +
  457 +1.11.2 Insert FIT CSF and DEK blob
  458 +-----------------------------------
  459 +
  460 +- Insert csf_fit_sign_enc.bin in encrypted-flash.bin at 0x58c20 offset:
  461 +
  462 + $ dd if=csf_fit_sign_enc.bin of=encrypted-flash.bin seek=$((0x58c20)) bs=1 conv=notrunc
  463 +
  464 +- The DEK blob must be inserted in last image entry on FIT image, the last line
  465 + provided by print_fit_hab taget log target can be used:
  466 +
  467 + 0x40200000 0x5AC00 0xB0318
  468 + 0x402B0318 0x10AF18 0x8628
  469 + 0x920000 0x113540 0xA160
  470 + 0xBE000000 0x11D6A0 0x48520 -> Last line in print_fit_hab log
  471 +
  472 +- Insert dek_fit_blob.bin encrypted-flash.bin at 0x11D6A0 + 0x48520 offset:
  473 +
  474 + $ dd if=dek_fit_blob.bin of=encrypted-flash.bin seek=$((0x165BC0)) bs=1 conv=notrunc
  475 +
  476 +1.11.3 Flash encrypted boot image
  477 +-----------------------------------
  478 +
  479 +- Flash encrypted image in SDCard:
  480 +
  481 + $ sudo dd if=encrypted-flash.bin of=/dev/sd<x> bs=1K seek=33* && sync
  482 + * Offset in i.MX8MN device is 32K.
  483 +
  484 +2.0 Setting the PRIBLOB in CAAM SCFGR register
  485 +-----------------------------------------------
  486 +
  487 +It is highly recommended to advance the PRIBLOB field in CAAM SCFGR register to
  488 +0x3, a command is available in U-Boot that should be called after all images in
  489 +boot flow has been decrypted by HAB:
  490 +
  491 + => set_priblob_bitfield
  492 +
  493 +The PRIBLOB configuration ensures cryptographic separation of private blob
  494 +types avoiding any modification or replacement of DEK blobs. Newly created
  495 +blobs will be incompatible with blobs required to decrypt an encrypted boot
  496 +image. When the HAB later executes the command to decrypt the DEK, an
  497 +incompatible DEK blob will be detected and cause an error. A substitute
  498 +encrypted boot image will not be decrypted, and will not be executed.
  499 +
  500 +References:
  501 +[1] AN12056: "Encrypted Boot on HABv4 and CAAM Enabled Devices" - Rev. 1