Device Tree Bindings
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The following properties are required in the FIT's signature node(s) to
-allow thes signer to operate. These should be added to the .its file.
+allow the signer to operate. These should be added to the .its file.
Signature nodes sit at the same level as hash nodes and are called
signature@1, signature@2, etc.
- required: If present this indicates that the key must be verified for the
image / configuration to be considered valid. Only required keys are
normally verified by the FIT image booting algorithm. Valid values are
-"image" to force verification of all images, and "conf" to force verfication
+"image" to force verification of all images, and "conf" to force verification
of the selected configuration (which then relies on hashes in the images to
verify those).
With signed images, nothing protects against this. Whether it gains an
advantage for the attacker is debatable, but it is not secure.
-To solved this problem, we support signed configurations. In this case it
+To solve this problem, we support signed configurations. In this case it
is the configurations that are signed, not the image. Each image has its
own hash, and we include the hash in the configuration signature.
In addition to the options to enable FIT itself, the following CONFIGs must
be enabled:
-CONFIG_FIT_SIGNATURE - enable signing and verfication in FITs
+CONFIG_FIT_SIGNATURE - enable signing and verification in FITs
CONFIG_RSA - enable RSA algorithm for signing
WARNING: When relying on signed FIT images with required signature check
Testing
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-An easy way to test signing and verfication is to use the test script
+An easy way to test signing and verification is to use the test script
provided in test/vboot/vboot_test.sh. This uses sandbox (a special version
of U-Boot which runs under Linux) to show the operation of a 'bootm'
command loading and verifying images.