heads/initrd/bin/tpmr

#!/bin/bash
# TPM Wrapper - to unify tpm and tpm2 subcommands

. /etc/functions

SECRET_DIR="/tmp/secret"
PRIMARY_HANDLE="0x81000000"
ENC_SESSION_FILE="enc.ctx"
DEC_SESSION_FILE="dec.ctx"
PRIMARY_HANDLE_FILE="primary.handle"

set -e -o pipefail
if [ -r "/tmp/config" ]; then
	. /tmp/config
else
	. /etc/config
fi

if [ "$CONFIG_TPM2_TOOLS" != "y" ]; then
	# tpm1 does not need to convert options
	if [ "$CONFIG_TPM" = "y" ]; then
		exec tpm "$@"
	fi
	echo >&2 "No TPM2!"
	exit 1
fi

tpm2_extend() {
	while true; do
		case "$1" in
			-ix)
				index="$2"
				shift 2;;
			-ic)
				hash="`echo $2|sha256sum|cut -d' ' -f1`"
				shift 2;;
			-if)
				hash="`sha256sum $2|cut -d' ' -f1`"
				shift 2;;
			*)
				break;;
		esac
	done
	tpm2 pcrextend "$index:sha256=$hash"
	exec tpm2 pcrread "sha256:$index"
}

tpm2_counter_read() {
	while true; do
		case "$1" in
			-ix)
				index="$2"
				shift 2;;
			*)
				break;;
		esac
	done
	echo "$index: `tpm2 nvread 0x$index | xxd -pc8`"
}

tpm2_counter_inc() {
	while true; do
		case "$1" in
			-ix)
				index="$2"
				shift 2;;
			-pwdc)
				pwd="$2"
				shift 2;;
			*)
				break;;
		esac
	done
	tpm2 nvincrement "0x$index" > /dev/console
	echo "$index: `tpm2 nvread 0x$index | xxd -pc8`"
}

tpm2_counter_cre() {
	while true; do
		case "$1" in
			-pwdo)
				pwdo="$2"
				shift 2;;
			-pwdof)
				pwdo="file:$2"
				shift 2;;
			-pwdc)
				pwd="$2"
				shift 2;;
			-la)
				label="$2"
				shift 2;;
			*)
				break;;
		esac
	done
	rand_index="1`dd if=/dev/urandom bs=1 count=3 | xxd -pc3`"
	tpm2 nvdefine -C o -s 8 -a "ownerread|authread|authwrite|nt=1" -P "$pwdo" "0x$rand_index" > /dev/console
	echo "$rand_index: (valid after an increment)"
}

tpm2_startsession() {
	mkdir -p "$SECRET_DIR"
	tpm2 flushcontext \
		--transient-object \
		|| die "tpm2_flushcontext: unable to flush transient handles"

	tpm2 flushcontext \
		--loaded-session \
		|| die "tpm2_flushcontext: unable to flush sessions"

	tpm2 flushcontext \
		--saved-session \
		|| die "tpm2_flushcontext: unable to flush saved session"
	tpm2 readpublic -c "$PRIMARY_HANDLE" -t "/tmp/$PRIMARY_HANDLE_FILE"
	tpm2 startauthsession -c "/tmp/$PRIMARY_HANDLE_FILE" --hmac-session -S "/tmp/$ENC_SESSION_FILE"
	tpm2 startauthsession -c "/tmp/$PRIMARY_HANDLE_FILE" --hmac-session -S "/tmp/$DEC_SESSION_FILE"
	tpm2 sessionconfig --disable-encrypt "/tmp/$DEC_SESSION_FILE"
}

tpm2_sealfile() {
	#TODO remove this: tpmr seal "$KEY_FILE" "0x8100000$TPM_INDEX" sha256:0,1,2,3,4,5,6,7 "$pcrf" "$key_password"
	file="$1" #$KEY_FILE
	handle="$2" # 0x8100000$TPM_INDEX
	pcrl="$3" #sha256:0,1,2,3,4,5,6,7
	pcrf="$4"
	pass="$5"
	mkdir -p "$SECRET_DIR"
	bname="`basename $file`"
	tpm2 createpolicy --policy-pcr -l "$pcrl" -f "$pcrf" -L "$SECRET_DIR/pcr.policy"
	if [ "$pass" ];then
		tpm2 create -C "/tmp/$PRIMARY_HANDLE_FILE" -i "$file" -u "$SECRET_DIR/$bname.priv" -r "$SECRET_DIR/$bname.pub" -L "$SECRET_DIR/pcr.policy" -S "/tmp/$DEC_SESSION_FILE" -p "$pass"
	else
		tpm2 create -C "/tmp/$PRIMARY_HANDLE_FILE" -i "$file" -u "$SECRET_DIR/$bname.priv" -r "$SECRET_DIR/$bname.pub" -L "$SECRET_DIR/pcr.policy" -S "/tmp/$DEC_SESSION_FILE"
	fi
	tpm2 load -C "/tmp/$PRIMARY_HANDLE_FILE" -u "$SECRET_DIR/$bname.priv" -r "$SECRET_DIR/$bname.pub" -c "$SECRET_DIR/$bname.seal.ctx"
	read -s -p "TPM owner password: " key_password
	# remove possible data occupying this handle
	tpm2 evictcontrol -C o -P "$key_password" -c "$handle" 2>/dev/null || true
	tpm2 evictcontrol -C o -P "$key_password" -c "$SECRET_DIR/$bname.seal.ctx" "$handle" 
}

tpm2_unseal() {
	#TODO: remove this: tpmr unseal "0x8100000$TPM_INDEX" "sha256:0,1,2,3,4,5,6,7" "file:-" > "$key_file"
	handle="$1"
	pcrl="$2"
	pass="$3"
	echo "debug handle: $handle prcl: $pcrl pass $pass" 
	if [ "$pass" ];then
		tpm2 unseal -c "$handle" -S "/tmp/$ENC_SESSION_FILE" -p "pcr:$pcrl+$pass"
	else
		tpm2 unseal -c "$handle" -S "/tmp/$ENC_SESSION_FILE" -p "pcr:$pcrl"
	fi
}

tpm2_reset() {
	key_password="$1"
	mkdir -p "$SECRET_DIR"
	tpm2 clear -c platform || warn "Unable to clear TPM on platform hierarchy!"
	tpm2 changeauth -c owner "$key_password"
	tpm2 createprimary -C owner -g sha256 -G "${CONFIG_PRIMARY_KEY_TYPE:-rsa}" -c "$SECRET_DIR/primary.ctx" -P "$key_password"
	tpm2 evictcontrol -C owner -c "$SECRET_DIR/primary.ctx" "$PRIMARY_HANDLE" -P "$key_password"
	shred -u "$SECRET_DIR/primary.ctx"
	tpm2_startsession
}
subcmd="$1"
shift 1
case "$subcmd" in
	extend)
		tpm2_extend "$@";;
	counter_read)
		tpm2_counter_read "$@";;
	counter_increment)
		tpm2_counter_inc "$@";;
	counter_create)
		tpm2_counter_cre "$@";;
	nv_definespace)
		tpm2_nvdef "$@";;
	nv_writevalue)
		tpm2_nvw "$@";;
	nv_readvalue)
		tpm2_nvr "$@";;
	seal)
		tpm2_sealfile "$@";;
	startsession)
		tpm2_startsession "$@";;
	unseal)
		tpm2_unseal "$@";;
	reset)
		tpm2_reset "$@";;
	*)
		echo "Command $subcmd not wrapped!"
		exit 1
esac