[PATCH v11 4/9] doc: update UEFI document for usage of mkeficapsule

AKASHI Takahiro takahiro.akashi at linaro.org
Wed Feb 9 11:10:37 CET 2022


Now we can use mkeficapsule command instead of EDK-II's script
to create a signed capsule file. So update the instruction for
capsule authentication.

Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
Reviewed-by: Simon Glass <sjg at chromium.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---
 doc/develop/uefi/uefi.rst | 151 +++++++++++++++++++-------------------
 1 file changed, 76 insertions(+), 75 deletions(-)

diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst
index 43fb10f7978e..52a38c6b231c 100644
--- a/doc/develop/uefi/uefi.rst
+++ b/doc/develop/uefi/uefi.rst
@@ -284,37 +284,56 @@ Support has been added for the UEFI capsule update feature which
 enables updating the U-Boot image using the UEFI firmware management
 protocol (FMP). The capsules are not passed to the firmware through
 the UpdateCapsule runtime service. Instead, capsule-on-disk
-functionality is used for fetching the capsule from the EFI System
-Partition (ESP) by placing the capsule file under the
-\EFI\UpdateCapsule directory.
-
-The directory \EFI\UpdateCapsule is checked for capsules only within the
-EFI system partition on the device specified in the active boot option
-determined by reference to BootNext variable or BootOrder variable processing.
-The active Boot Variable is the variable with highest priority BootNext or
-within BootOrder that refers to a device found to be present. Boot variables
-in BootOrder but referring to devices not present are ignored when determining
-active boot variable.
-Before starting a capsule update make sure your capsules are installed in the
-correct ESP partition or set BootNext.
+functionality is used for fetching capsules from the EFI System
+Partition (ESP) by placing capsule files under the directory::
+
+    \EFI\UpdateCapsule
+
+The directory is checked for capsules only within the
+EFI system partition on the device specified in the active boot option,
+which is determined by BootXXXX variable in BootNext, or if not, the highest
+priority one within BootOrder. Any BootXXXX variables referring to devices
+not present are ignored when determining the active boot option.
+
+Please note that capsules will be applied in the alphabetic order of
+capsule file names.
+
+Creating a capsule file
+***********************
+
+A capsule file can be created by using tools/mkeficapsule.
+To build this tool, enable::
+
+    CONFIG_TOOLS_MKEFICAPSULE=y
+    CONFIG_TOOLS_LIBCRYPTO=y
+
+Run the following command
+
+.. code-block:: console
+
+    $ mkeficapsule \
+      --index 1 --instance 0 \
+      [--fit <FIT image> | --raw <raw image>] \
+      <capsule_file_name>
 
 Performing the update
 *********************
 
-Since U-boot doesn't currently support SetVariable at runtime there's a Kconfig
-option (CONFIG_EFI_IGNORE_OSINDICATIONS) to disable the OsIndications variable
-check. If that option is enabled just copy your capsule to \EFI\UpdateCapsule.
+Put capsule files under the directory mentioned above.
+Then, following the UEFI specification, you'll need to set
+the EFI_OS_INDICATIONS_FILE_CAPSULE_DELIVERY_SUPPORTED
+bit in OsIndications variable with
 
-If that option is disabled, you'll need to set the OsIndications variable with::
+.. code-block:: console
 
     => setenv -e -nv -bs -rt -v OsIndications =0x04
 
-Finally, the capsule update can be initiated either by rebooting the board,
-which is the preferred method, or by issuing the following command::
-
-    => efidebug capsule disk-update
+Since U-boot doesn't currently support SetVariable at runtime, its value
+won't be taken over across the reboot. If this is the case, you can skip
+this feature check with the Kconfig option (CONFIG_EFI_IGNORE_OSINDICATIONS)
+set.
 
-**The efidebug command is should only be used during debugging/development.**
+Finally, the capsule update can be initiated by rebooting the board.
 
 Enabling Capsule Authentication
 *******************************
@@ -324,82 +343,64 @@ be updated by verifying the capsule signature. The capsule signature
 is computed and prepended to the capsule payload at the time of
 capsule generation. This signature is then verified by using the
 public key stored as part of the X509 certificate. This certificate is
-in the form of an efi signature list (esl) file, which is embedded as
-part of U-Boot.
+in the form of an efi signature list (esl) file, which is embedded in
+a device tree.
 
 The capsule authentication feature can be enabled through the
 following config, in addition to the configs listed above for capsule
 update::
 
     CONFIG_EFI_CAPSULE_AUTHENTICATE=y
-    CONFIG_EFI_CAPSULE_KEY_PATH=<path to .esl cert>
 
 The public and private keys used for the signing process are generated
-and used by the steps highlighted below::
+and used by the steps highlighted below.
 
-    1. Install utility commands on your host
-       * OPENSSL
+1. Install utility commands on your host
+       * openssl
        * efitools
 
-    2. Create signing keys and certificate files on your host
+2. Create signing keys and certificate files on your host
 
-        $ openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=CRT/ \
-            -keyout CRT.key -out CRT.crt -nodes -days 365
-        $ cert-to-efi-sig-list CRT.crt CRT.esl
+.. code-block:: console
 
-        $ openssl x509 -in CRT.crt -out CRT.cer -outform DER
-        $ openssl x509 -inform DER -in CRT.cer -outform PEM -out CRT.pub.pem
+    $ openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=CRT/ \
+        -keyout CRT.key -out CRT.crt -nodes -days 365
+    $ cert-to-efi-sig-list CRT.crt CRT.esl
 
-        $ openssl pkcs12 -export -out CRT.pfx -inkey CRT.key -in CRT.crt
-        $ openssl pkcs12 -in CRT.pfx -nodes -out CRT.pem
+3. Run the following command to create and sign the capsule file
 
-The capsule file can be generated by using the GenerateCapsule.py
-script in EDKII::
+.. code-block:: console
 
-    $ ./BaseTools/BinWrappers/PosixLike/GenerateCapsule -e -o \
-      <capsule_file_name> --monotonic-count <val> --fw-version \
-      <val> --lsv <val> --guid \
-      e2bb9c06-70e9-4b14-97a3-5a7913176e3f --verbose \
-      --update-image-index <val> --signer-private-cert \
-      /path/to/CRT.pem --trusted-public-cert \
-      /path/to/CRT.pub.pem --other-public-cert /path/to/CRT.pub.pem \
-      <u-boot.bin>
+    $ mkeficapsule --monotonic-count 1 \
+      --private-key CRT.key \
+      --certificate CRT.crt \
+      --index 1 --instance 0 \
+      [--fit <FIT image> | --raw <raw image>] \
+      <capsule_file_name>
 
-Place the capsule generated in the above step on the EFI System
-Partition under the EFI/UpdateCapsule directory
+4. Insert the signature list into a device tree in the following format::
 
-Testing on QEMU
-***************
+    {
+            signature {
+                    capsule-key = [ <binary of signature list> ];
+            }
+            ...
+    }
 
-Currently, support has been added on the QEMU ARM64 virt platform for
-updating the U-Boot binary as a raw image when the platform is booted
-in non-secure mode, i.e. with CONFIG_TFABOOT disabled. For this
-configuration, the QEMU platform needs to be booted with
-'secure=off'. The U-Boot binary placed on the first bank of the NOR
-flash at offset 0x0. The U-Boot environment is placed on the second
-NOR flash bank at offset 0x4000000.
+You can do step-4 manually with
 
-The capsule update feature is enabled with the following configuration
-settings::
+.. code-block:: console
 
-    CONFIG_MTD=y
-    CONFIG_FLASH_CFI_MTD=y
-    CONFIG_CMD_MTDPARTS=y
-    CONFIG_CMD_DFU=y
-    CONFIG_DFU_MTD=y
-    CONFIG_PCI_INIT_R=y
-    CONFIG_EFI_CAPSULE_ON_DISK=y
-    CONFIG_EFI_CAPSULE_FIRMWARE_MANAGEMENT=y
-    CONFIG_EFI_CAPSULE_FIRMWARE=y
-    CONFIG_EFI_CAPSULE_FIRMWARE_RAW=y
+    $ dtc -@ -I dts -O dtb -o signature.dtbo signature.dts
+    $ fdtoverlay -i orig.dtb -o new.dtb -v signature.dtbo
 
-In addition, the following config needs to be disabled(QEMU ARM specific)::
+where signature.dts looks like::
 
-    CONFIG_TFABOOT
-
-The capsule file can be generated by using the tools/mkeficapsule::
-
-    $ mkeficapsule --raw <u-boot.bin> --index 1 <capsule_file_name>
+    &{/} {
+            signature {
+                    capsule-key = /incbin/("CRT.esl");
+            };
+    };
 
 Executing the boot manager
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
-- 
2.33.0



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