From 33bbd1de5ec9b8802d63e811908f2351ba83884c Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 16 Nov 2010 16:33:17 +0200 Subject: optionrom: fix bugs in signrom.sh signrom.sh has multiple bugs: - the last byte is considered when calculating the existing checksum, but not when computing the correction - apprently the 'expr' expression overflows and produces incorrect results with larger roms - if the checksum happened to be zero, we calculated the correction byte to be 256 Instead of rewriting this in half a line of python, this patch fixes the bugs. Signed-off-by: Avi Kivity Signed-off-by: Anthony Liguori --- pc-bios/optionrom/signrom.sh | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/pc-bios/optionrom/signrom.sh b/pc-bios/optionrom/signrom.sh index 975b27dd60..9dc5c63dde 100755 --- a/pc-bios/optionrom/signrom.sh +++ b/pc-bios/optionrom/signrom.sh @@ -31,14 +31,13 @@ x=`dd if="$1" bs=1 count=1 skip=2 2>/dev/null | od -t u1 -A n` size=$(( $x * 512 - 1 )) # now get the checksum -nums=`od -A n -t u1 -v "$1"` +nums=`od -A n -t u1 -v -N $size "$1"` for i in ${nums}; do # add each byte's value to sum - sum=`expr $sum + $i` + sum=`expr \( $sum + $i \) % 256` done -sum=$(( $sum % 256 )) -sum=$(( 256 - $sum )) +sum=$(( (256 - $sum) % 256 )) sum_octal=$( printf "%o" $sum ) # and write the output file -- cgit v1.2.3