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Diffstat (limited to 'src/genhmac.sh')
| -rwxr-xr-x | src/genhmac.sh | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/src/genhmac.sh b/src/genhmac.sh new file mode 100755 index 00000000..bb33b9c6 --- /dev/null +++ b/src/genhmac.sh @@ -0,0 +1,83 @@ +#! /bin/sh + +# +# genhmac.sh - Build tool to generate hmac hash +# +# Copyright (C) 2022 g10 Code GmbH +# +# This file is part of libgcrypt. +# +# libgcrypt is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public License +# as published by the Free Software Foundation; either version 2.1 of +# the License, or (at your option) any later version. +# +# libgcrypt is distributed in the hope that it will be useful, but +# WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with this program; if not, see <https://www.gnu.org/licenses/>. +# + +set -e + +# +# Following variables should be defined to invoke this script +# +# READELF +# AWK +# + +AWK_VERSION_OUTPUT=$($AWK 'BEGIN { print PROCINFO["version"] }') +if test -n "$AWK_VERSION_OUTPUT"; then + # It's GNU awk, which supports PROCINFO. + AWK_OPTION=--non-decimal-data +fi + +FILE=.libs/libgcrypt.so + +# +# Fixup the ELF header to clean up section information +# +printf '%b' '\002' > 2.bin +dd ibs=1 skip=4 count=1 if=$FILE status=none > class-byte.bin +if cmp class-byte.bin 2.bin; then + CLASS=64 + HEADER_SIZE=64 +else + CLASS=32 + HEADER_SIZE=52 +fi + +if test $CLASS -eq 64; then + dd ibs=1 count=40 if=$FILE status=none + dd ibs=1 count=8 if=/dev/zero status=none + dd ibs=1 skip=48 count=10 if=$FILE status=none + dd ibs=1 count=6 if=/dev/zero status=none +else + dd ibs=1 count=32 if=$FILE status=none + dd ibs=1 count=4 if=/dev/zero status=none + dd ibs=1 skip=36 count=10 if=$FILE status=none + dd ibs=1 count=6 if=/dev/zero status=none +fi > header-fixed.bin + +# Compute the end of loadable segment. +# +# This require computation in hexadecimal, and GNU awk needs +# --non-decimal-data option +# +OFFSET=$($READELF --wide --program-headers $FILE | \ + $AWK $AWK_OPTION "/^ LOAD/ { offset=\$2+\$5-$HEADER_SIZE }\ +END { print offset}") + +# +# Feed the header fixed and loadable segments to HMAC256 +# to generate hmac hash of the FILE +# +(cat header-fixed.bin; \ + dd ibs=1 skip=$HEADER_SIZE count=$OFFSET if=$FILE status=none) \ + | ./hmac256 --stdkey --binary + +rm -f 2.bin class-byte.bin header-fixed.bin |