From 4ab023329d9212342cf6f7cfa08fb388ac7f019b Mon Sep 17 00:00:00 2001 From: Paul Fagerburg Date: Wed, 25 Sep 2019 09:12:24 -0600 Subject: [PATCH] util/mb/google/hatch: update CRC calculation for correctness The CRC result is treated as a signed value, and so in certain situations, the calculated value for the last four digits will not be correct. Ensure that the CRC is treated as an unsigned 32-bit value prior to converting the last 4 decimal digits to a string. Signed-off-by: Paul Fagerburg Change-Id: I92f9ce1ceb7450f90b89c94e0ace6f79a9419b42 Reviewed-on: https://review.coreboot.org/c/coreboot/+/35604 Reviewed-by: Andrew McRae Reviewed-by: Edward O'Callaghan Reviewed-by: Tim Wawrzynczak Tested-by: build bot (Jenkins) --- util/mainboard/google/hatch/kconfig.py | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/util/mainboard/google/hatch/kconfig.py b/util/mainboard/google/hatch/kconfig.py index ecc24eeb49..891714b53e 100755 --- a/util/mainboard/google/hatch/kconfig.py +++ b/util/mainboard/google/hatch/kconfig.py @@ -64,8 +64,11 @@ def get_gbb_hwid(variant_name): converted to all uppercase as part of this function.""" hwid = variant_name + ' test' upperhwid = hwid.upper() - suffix = zlib.crc32(upperhwid.encode('UTF-8')) % 10000 - gbb_hwid = upperhwid + ' ' + str(suffix).zfill(4) + # Force conversion to unsigned by bitwise AND with (2^32)-1. + # See the docs for crc32 at https://docs.python.org/3/library/zlib.html + # for why '& 0xffffffff' is necessary. + crc = zlib.crc32(upperhwid.encode('UTF-8')) & 0xffffffff + gbb_hwid = upperhwid + ' ' + str(crc % 10000).zfill(4) return gbb_hwid