@@ -100,79 +100,93 @@ See doc/uImage.FIT/howto.txt for an introduction to FIT images.
Configuring UEFI secure boot
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-UEFI specification[1] defines a secure way of executing UEFI images
+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, you can make it with the UEFI variables, "PK"
-(Platform Key), "KEK" (Key Exchange Keys), "db" (white list database)
-and "dbx" (black list database).
+In UEFI secure boot the chain trust is defined by the following UEFI variables
-There are many online documents that describe what UEFI secure boot is
-and how it works. Please consult some of them for details.
+* PK - Platform Key
+* KEK - Key Exchange Keys
+* db - white list database
+* dbx - black list database
-Here is a simple example that you can follow for your initial attempt
-(Please note that the actual steps would absolutely depend on your system
-and environment.):
+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.):
-1. Install utility commands on your host
- * openssl
- * efitools
- * sbsigntool
+Install the required tools on your host
-2. Create signing keys and key database files on your host
- for PK::
+* openssl
+* efitools
+* sbsigntool
- $ 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
+Create signing keys and the key database on your host:
- for KEK::
+The platform key
- $ 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
+.. code-block:: bash
- for db::
+ 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
- $ 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
+The key exchange keys
- Copy \*.auth to media, say mmc, that is accessible from U-Boot.
+.. code-block:: bash
-3. Sign an image with one key in "db" on your host::
+ 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
- $ sbsign --key db.key --cert db.crt helloworld.efi
+The whitelist database
-4. Install keys on your board::
+.. code-block:: bash
- ==> 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
+ $ 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
-5. Set up boot parameters on your board::
+Copy the \*.auth files to media, say mmc, that is accessible from U-Boot.
- ==> efidebug boot add 1 HELLO mmc 0:1 /helloworld.efi.signed ""
+Sign an image with one of the keys in "db" on your host
-Then your board runs that image from Boot manager (See below).
+.. 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 sandbox::
+on the sandbox
+
+.. code-block:: bash
- $ cd <U-Boot source directory>
- $ pytest.py test/py/tests/test_efi_secboot/test_signed.py --bd sandbox
+ cd <U-Boot source directory>
+ pytest.py test/py/tests/test_efi_secboot/test_signed.py --bd sandbox
Executing the boot manager
~~~~~~~~~~~~~~~~~~~~~~~~~~
Ensure a uniform formatting. Some rephrasing. Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de> --- doc/uefi/uefi.rst | 110 ++++++++++++++++++++++++++-------------------- 1 file changed, 62 insertions(+), 48 deletions(-) -- 2.25.1