33bbd1de5e
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 <avi@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
46 lines
1.3 KiB
Bash
Executable File
46 lines
1.3 KiB
Bash
Executable File
#!/bin/sh
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# Option ROM Signing utility
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, see <http://www.gnu.org/licenses/>.
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#
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# Copyright Novell Inc, 2009
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# Authors: Alexander Graf <agraf@suse.de>
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#
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# Syntax: signrom.sh <input> <output>
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# did we get proper arguments?
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test "$1" -a "$2" || exit 1
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sum=0
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# find out the file size
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x=`dd if="$1" bs=1 count=1 skip=2 2>/dev/null | od -t u1 -A n`
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#size=`expr $x \* 512 - 1`
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size=$(( $x * 512 - 1 ))
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# now get the checksum
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nums=`od -A n -t u1 -v -N $size "$1"`
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for i in ${nums}; do
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# add each byte's value to sum
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sum=`expr \( $sum + $i \) % 256`
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done
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sum=$(( (256 - $sum) % 256 ))
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sum_octal=$( printf "%o" $sum )
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# and write the output file
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cp "$1" "$2"
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printf "\\$sum_octal" | dd of="$2" bs=1 count=1 seek=$size conv=notrunc 2>/dev/null
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