heads/initrd/sbin/insmod
Thierry Laurion bec2545688
insmod: check if module already loaded and if so exit early
Signed-off-by: Thierry Laurion <insurgo@riseup.net>
2024-02-22 14:15:06 -05:00

60 lines
1.4 KiB
Bash
Executable File

#!/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 "$MODULE: not found?"
fi
# Check if module is already loaded while remove trailing .ko if present
module=$(basename "$MODULE")
module=${module%.ko}
if lsmod | grep -q "^$module\\b"; then
DEBUG "$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"