They allow optimizing a verification of a whole CBFS image by only
dealing with the headers (assuming you choose to trust the hash
algorithm(s)).
The format allows for multiple hashes for a single file, and cbfstool
can handle them, but right now it can't generate such headers.
Loosely based on Sol's work in http://review.coreboot.org/#/c/10147/,
but using the compatible file attribute format. vboot is now a hard
dependency of the build process, but we import it into the tree for
quite a while now.
Change-Id: I9f14f30537d676ce209ad612e7327c6f4810b313
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/11767
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>