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2017-01-25util: Add me_cleanerNicola Corna
me_cleaner is a tool to strip down Intel ME/TXE images by removing all the non-fundamental code, while keeping the ME/TXE image valid and suitable for booting the system. The remaining code (ROMP and BUP modules) is the one responsible for the very basic initialization of the ME/TXE subsystem and can't be removed. This tool exploits the fact that: * Each ME/TXE partition is signed individually and it is possible to remove both the partition and the signature. * The ME/TXE modules are not signed directly, instead they are hashed and the list of their hashes is hashed again and signed: this means that modifying a module doesn't invalidate the signature, but only the hash of that single module. * The modules hashes are checked only when the corresponding module needs to be executed. * The system can boot after the execution of the first module (BUP, inside the FTPR partition), even if the subsequent stages fail. Currently me_cleaner works on every Intel platform with Intel ME or Intel TXE with the following limitations: * Doesn't work when Intel Boot Guard is set in Verified Boot mode. * Doesn't fully work on Nehalem yet. * On Skylake and later generations, since the partitions' internal structure has changed, me_cleaner leaves intact the FTPR partition, removing all the the other partitions. This tool has been tested on multiple platforms and architectures by different users, and seems to be stable. The reports are available here: https://github.com/corna/me_cleaner/issues/3 A more in-depth description of me_cleaner is available here: https://github.com/corna/me_cleaner/wiki/How-does-it-work%3F Change-Id: I9013799e9adea0dea0775b9afe718de5fc4ca748 Signed-off-by: Nicola Corna <nicola@corna.info> Reviewed-on: https://review.coreboot.org/18203 Tested-by: build bot (Jenkins) Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com> Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>