commonlib: Add function to hash contents of a CBFS region.

Provide a common routine to hash the contents of a cbfs
region. The cbfs region is hashed in the following order:
1. potential cbfs header at offset 0
2. potential cbfs header retlative offset at cbfs size - 4
3. For each file the metadata of the file.
4. For each non-empty file the data of the file.

TEST=Utilized in chromeos cros_bundle_firmware as well as at
      runtime during vboot verification on glados.

Change-Id: Ie1e5db5b8a80d9465e88d3f69f5367d887bdf73f
Signed-off-by: Aaron Durbin <>
Reviewed-by: Patrick Georgi <>
Tested-by: build bot (Jenkins)
5 files changed