See doc/uImage.FIT/howto.txt for an introduction to FIT images.
+Configuring UEFI secure boot
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The UEFI specification[1] defines a secure way of executing UEFI images
+by verifying a signature (or message digest) of image with certificates.
+This feature on U-Boot is enabled with::
+
+ CONFIG_UEFI_SECURE_BOOT=y
+
+To make the boot sequence safe, you need to establish a chain of trust;
+In UEFI secure boot the chain trust is defined by the following UEFI variables
+
+* PK - Platform Key
+* KEK - Key Exchange Keys
+* db - white list database
+* dbx - black list database
+
+An in depth description of UEFI secure boot is beyond the scope of this
+document. Please, refer to the UEFI specification and available online
+documentation. Here is a simple example that you can follow for your initial
+attempt (Please note that the actual steps will depend on your system and
+environment.):
+
+Install the required tools on your host
+
+* openssl
+* efitools
+* sbsigntool
+
+Create signing keys and the key database on your host:
+
+The platform key
+
+.. code-block:: bash
+
+ openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=TEST_PK/ \
+ -keyout PK.key -out PK.crt -nodes -days 365
+ cert-to-efi-sig-list -g 11111111-2222-3333-4444-123456789abc \
+ PK.crt PK.esl;
+ sign-efi-sig-list -c PK.crt -k PK.key PK PK.esl PK.auth
+
+The key exchange keys
+
+.. code-block:: bash
+
+ openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=TEST_KEK/ \
+ -keyout KEK.key -out KEK.crt -nodes -days 365
+ cert-to-efi-sig-list -g 11111111-2222-3333-4444-123456789abc \
+ KEK.crt KEK.esl
+ sign-efi-sig-list -c PK.crt -k PK.key KEK KEK.esl KEK.auth
+
+The whitelist database
+
+.. code-block:: bash
+
+ $ openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=TEST_db/ \
+ -keyout db.key -out db.crt -nodes -days 365
+ $ cert-to-efi-sig-list -g 11111111-2222-3333-4444-123456789abc \
+ db.crt db.esl
+ $ sign-efi-sig-list -c KEK.crt -k KEK.key db db.esl db.auth
+
+Copy the \*.auth files to media, say mmc, that is accessible from U-Boot.
+
+Sign an image with one of the keys in "db" on your host
+
+.. code-block:: bash
+
+ sbsign --key db.key --cert db.crt helloworld.efi
+
+Now in U-Boot install the keys on your board::
+
+ fatload mmc 0:1 <tmpaddr> PK.auth
+ setenv -e -nv -bs -rt -at -i <tmpaddr>,$filesize PK
+ fatload mmc 0:1 <tmpaddr> KEK.auth
+ setenv -e -nv -bs -rt -at -i <tmpaddr>,$filesize KEK
+ fatload mmc 0:1 <tmpaddr> db.auth
+ setenv -e -nv -bs -rt -at -i <tmpaddr>,$filesize db
+
+Set up boot parameters on your board::
+
+ efidebug boot add 1 HELLO mmc 0:1 /helloworld.efi.signed ""
+
+Now your board can run the signed image via the boot manager (see below).
+You can also try this sequence by running Pytest, test_efi_secboot,
+on the sandbox
+
+.. code-block:: bash
+
+ cd <U-Boot source directory>
+ pytest.py test/py/tests/test_efi_secboot/test_signed.py --bd sandbox
+
+Using OP-TEE for EFI variables
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Instead of implementing UEFI variable services inside U-Boot they can
+also be provided in the secure world by a module for OP-TEE[1]. The
+interface between U-Boot and OP-TEE for variable services is enabled by
+CONFIG_EFI_MM_COMM_TEE=y.
+
+Tianocore EDK II's standalone management mode driver for variables can
+be linked to OP-TEE for this purpose. This module uses the Replay
+Protected Memory Block (RPMB) of an eMMC device for persisting
+non-volatile variables. When calling the variable services via the
+OP-TEE API U-Boot's OP-TEE supplicant relays calls to the RPMB driver
+which has to be enabled via CONFIG_SUPPORT_EMMC_RPMB=y.
+
+[1] https://optee.readthedocs.io/ - OP-TEE documentation
+
Executing the boot manager
~~~~~~~~~~~~~~~~~~~~~~~~~~
CONFIG_BLK=y
CONFIG_PARTITIONS=y
+Miscellaneous
+-------------
+
+Load file 2 protocol
+~~~~~~~~~~~~~~~~~~~~
+
+The load file 2 protocol can be used by the Linux kernel to load the initial
+RAM disk. U-Boot can be configured to provide an implementation with::
+
+ EFI_LOAD_FILE2_INITRD=y
+ EFI_INITRD_FILESPEC=interface dev:part path_to_initrd
+
Links
-----
projects / oweals / u-boot.git / blobdiff