heads/initrd/sbin/insmod
2024-02-23 01:29:55 -05:00

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#!/bin/bash
# extend a TPM PCR with a module and then load it
# any arguments will also be measured.
# The default PCR to be extended is 5, but can be
# overridden with the MODULE_PCR environment variable
. /etc/functions
TRACE_FUNC
MODULE="$1"; shift
if [ -z "$MODULE_PCR" ]; then
MODULE_PCR=5
fi
if [ -z "$MODULE" ]; then
die "Usage: $0 module [args...]"
fi
if [ ! -r "$MODULE" ]; then
die "$MODULE: not found?"
fi
# Check if module is already loaded
# Transform module name changing _ for - and trailing .ko if present
# Unify lsmod output to use - instead of _ for comparison
module_name=$(basename "$MODULE" | sed 's/_/-/g' | sed 's/\.ko$//')
if lsmod | sed 's/_/-/g' | grep -q "^$module_name\\b"; then
DEBUG "$MODULE: already loaded"
exit 0
fi
if [ ! -r /sys/class/tpm/tpm0/pcrs -o ! -x /bin/tpm ]; then
if [ ! -c /dev/tpmrm0 -o ! -x /bin/tpm2 ]; then
tpm_missing=1
fi
fi
if [ -z "$tpm_missing" ]; then
DEBUG "Extending TPM PCR $MODULE_PCR with $MODULE prior of usage"
tpmr extend -ix "$MODULE_PCR" -if "$MODULE" \
|| die "$MODULE: tpm extend failed"
fi
if [ ! -z "$*" -a -z "$tpm_missing" ]; then
DEBUG "Extending TPM PCR $MODULE_PCR with $*"
TMPFILE=/tmp/insmod.$$
echo "$@" > $TMPFILE
DEBUG "Extending TPM PCR $MODULE_PCR with $MODULE prior of usage"
tpmr extend -ix "$MODULE_PCR" -if $TMPFILE \
|| die "$MODULE: tpm extend on arguments failed"
fi
# Since we have replaced the real insmod, we must invoke
# the busybox insmod via the original executable
DEBUG "Loading $MODULE with busybox insmod"
busybox insmod "$MODULE" "$@" \
|| die "$MODULE: insmod failed"