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authorPaul Fagerburg <pfagerburg@chromium.org>2019-09-25 09:12:24 -0600
committerPatrick Georgi <pgeorgi@google.com>2019-09-30 11:43:28 +0000
commit4ab023329d9212342cf6f7cfa08fb388ac7f019b (patch)
treeb1ca81931b69acc9e75fd1b7db57b168978429d7 /util/mainboard
parent39f3f52b3eb0fee0c9908e07d910270d05952c0d (diff)
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 <pfagerburg@chromium.org> Change-Id: I92f9ce1ceb7450f90b89c94e0ace6f79a9419b42 Reviewed-on: https://review.coreboot.org/c/coreboot/+/35604 Reviewed-by: Andrew McRae <amcrae@chromium.org> Reviewed-by: Edward O'Callaghan <quasisec@chromium.org> Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'util/mainboard')
-rwxr-xr-xutil/mainboard/google/hatch/kconfig.py7
1 files 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