Add initramfs-module-luks-ftpm providing LUKS2 full disk encryption with TPM-sealed keys for TI K3 platforms. Keys are sealed by firmware TPM (fTPM) running in OP-TEE and stored in eMMC RPMB.
Features: - First-boot in-place encryption with tpm2_getrandom key generation - TPM-sealed key storage via persistent handle 0x81080001 - Automatic unlock on subsequent boots - Space verification ensuring 32MB available for LUKS header Update packagegroup-ti-core-initramfs to conditionally include the module when MACHINE_FEATURES contains 'luks-encryption'. Signed-off-by: Shiva Tripathi <[email protected]> --- .../initramfs-module-luks-ftpm/luksftpm | 341 ++++++++++++++++++ .../initramfs-module-luks-ftpm_1.0.bb | 41 +++ .../packagegroup-ti-core-initramfs.bb | 1 + 3 files changed, 383 insertions(+) create mode 100644 meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm/luksftpm create mode 100644 meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm_1.0.bb diff --git a/meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm/luksftpm b/meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm/luksftpm new file mode 100644 index 00000000..5e3aedc4 --- /dev/null +++ b/meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm/luksftpm @@ -0,0 +1,341 @@ +#!/bin/sh +# initramfs-framework module for LUKS encryption with fTPM support + +# Configuration +BOOT_DEV="/dev/mmcblk1p1" # Boot partition (FAT, unencrypted) +ROOT_DEV="/dev/mmcblk1p2" # Root partition (will be encrypted) +CRYPT_NAME="root_crypt" +CRYPT_DEV="/dev/mapper/${CRYPT_NAME}" +BOOT_MNT="/boot_part" +TPM_PRIMARY_CTX="/tmp/tpm_primary.ctx" +TPM_KEY_PRIV="/tmp/tpm_key.priv" +TPM_KEY_PUB="/tmp/tpm_key.pub" +TPM_KEY_CTX="/tmp/tpm_key.ctx" +TPM2_HANDLE="0x81080001" # TPM persistent handle for LUKS key +ENCRYPTION_MARKER="${BOOT_MNT}/.encryption_in_progress" + +# Wait for MMC device to appear +wait_for_device() { + local device="$1" + local timeout="${2:-10}" + + msg "Waiting for storage device ${device}..." + for i in $(seq 1 ${timeout}); do + if [ -b "${device}" ]; then + return 0 + fi + sleep 1 + done + return 1 +} + +# Initialize fTPM and check availability +init_ftpm() { + msg "Initializing secure hardware (fTPM)..." + + # Start TEE supplicant (required for fTPM TA to work) + if [ -x /usr/sbin/tee-supplicant ]; then + /usr/sbin/tee-supplicant -d & + TEE_SUPPLICANT_PID=$! + sleep 5 + else + info "Warning: Trusted execution environment not available" + return 1 + fi + + # Load fTPM kernel module + if ! /sbin/modprobe tpm_ftpm_tee; then + info "Warning: TPM module failed to load" + return 1 + fi + + # Wait for TPM device + for i in $(seq 1 10); do + if [ -c /dev/tpmrm0 ]; then + export TPM2TOOLS_TCTI="device:/dev/tpmrm0" + return 0 + fi + sleep 1 + done + + info "Warning: fTPM not available - encryption will be skipped" + return 1 +} + +# Generate 32-byte random key using TPM RNG +generate_random_key() { + /usr/bin/tpm2_getrandom --hex 32 +} + +# Seal data with TPM and store in persistent handle +tpm_seal_key() { + local KEY_DATA="$1" + + # Create primary key in owner hierarchy + /usr/bin/tpm2_createprimary -C o -c "${TPM_PRIMARY_CTX}" -Q || return 1 + + # Create sealed object + echo -n "${KEY_DATA}" | \ + /usr/bin/tpm2_create -C "${TPM_PRIMARY_CTX}" \ + -u "${TPM_KEY_PUB}" -r "${TPM_KEY_PRIV}" \ + -i- -Q || return 1 + + # Load sealed object into TPM + /usr/bin/tpm2_load -C "${TPM_PRIMARY_CTX}" \ + -u "${TPM_KEY_PUB}" -r "${TPM_KEY_PRIV}" \ + -c "${TPM_KEY_CTX}" -Q || return 1 + + # Make key persistent at handle (stored in TPM NV RAM - RPMB) + /usr/bin/tpm2_evictcontrol -C o -c "${TPM_KEY_CTX}" "${TPM2_HANDLE}" || return 1 + + return 0 +} + +# Unseal data from TPM persistent handle +tpm_unseal_key() { + # Check if persistent handle exists + if ! /usr/bin/tpm2_getcap handles-persistent | grep -q "${TPM2_HANDLE}"; then + debug "ERROR: TPM persistent handle not found" + return 1 + fi + + # Unseal key directly from persistent handle + /usr/bin/tpm2_unseal -c "${TPM2_HANDLE}" || return 1 + + return 0 +} + +# Perform in-place LUKS encryption (first boot) +encrypt_root_filesystem() { + msg "==========================================" + msg "First boot: Encrypting root filesystem" + msg "==========================================" + + # Set marker to track encryption progress + touch "${ENCRYPTION_MARKER}" + sync + + # Generate random encryption key using TPM RNG + msg "Generating encryption key..." + LUKS_KEY=$(generate_random_key) + + if [ -z "${LUKS_KEY}" ]; then + msg "ERROR: Failed to generate encryption key" + rm -f "${ENCRYPTION_MARKER}" + return 1 + fi + + # Seal key with TPM before encryption starts + msg "Securing key with TPM..." + if ! tpm_seal_key "${LUKS_KEY}"; then + msg "ERROR: Failed to secure key" + rm -f "${ENCRYPTION_MARKER}" + return 1 + fi + + # Filesystem check before encryption + msg "Checking filesystem integrity..." + /usr/sbin/e2fsck -f -y "${ROOT_DEV}" + E2FSCK_RET=$? + if [ ${E2FSCK_RET} -ge 4 ]; then + msg "ERROR: Filesystem check failed" + rm -f "${ENCRYPTION_MARKER}" + return 1 + fi + + # Shrink filesystem before encryption to leave room for LUKS header + msg "Preparing filesystem for encryption..." + /usr/sbin/resize2fs -M "${ROOT_DEV}" || { + msg "ERROR: Failed to prepare filesystem" + rm -f "${ENCRYPTION_MARKER}" + return 1 + } + + # Verify partition has sufficient space for LUKS header + msg "Verifying space for encryption..." + MIN_BLOCKS=$(/usr/sbin/resize2fs -P "${ROOT_DEV}" 2>&1 | awk '/[Mm]inimum.*:/ {print $NF}') + + # Get filesystem block size and device size + BLOCK_SIZE=$(/usr/sbin/tune2fs -l "${ROOT_DEV}" 2>/dev/null | awk '/^Block size:/ {print $NF}') + DEV_NAME=$(basename "${ROOT_DEV}") + PART_SECTORS=$(cat /sys/class/block/"${DEV_NAME}"/size 2>/dev/null) + + if [ -z "${MIN_BLOCKS}" ] || [ -z "${BLOCK_SIZE}" ] || [ -z "${PART_SECTORS}" ]; then + msg "ERROR: Unable to determine partition geometry" + rm -f "${ENCRYPTION_MARKER}" + return 1 + fi + + # Convert filesystem blocks to 512-byte sectors + MIN_SECTORS=$((MIN_BLOCKS * BLOCK_SIZE / 512)) + LUKS_SECTORS=65536 # 32MB in 512-byte sectors + + if [ $((PART_SECTORS - MIN_SECTORS)) -lt ${LUKS_SECTORS} ]; then + msg "ERROR: Insufficient space for LUKS header (need 32MB free)" + rm -f "${ENCRYPTION_MARKER}" + return 1 + fi + + # Perform in-place encryption + msg "==========================================" + msg "Encrypting filesystem..." + msg "This will take several minutes." + msg "DO NOT POWER OFF THE DEVICE!" + msg "==========================================" + + echo -n "${LUKS_KEY}" | \ + /usr/sbin/cryptsetup reencrypt --encrypt \ + --type luks2 \ + --cipher aes-xts-plain64 \ + --key-size 256 \ + --hash sha256 \ + --reduce-device-size 32M \ + --key-file - \ + "${ROOT_DEV}" || { + msg "ERROR: Encryption failed" + rm -f "${ENCRYPTION_MARKER}" + return 1 + } + + msg "==========================================" + msg "Encryption completed successfully!" + msg "==========================================" + + # Remove encryption marker + rm -f "${ENCRYPTION_MARKER}" + sync + + # Unlock the newly encrypted device + msg "Activating encrypted filesystem..." + echo -n "${LUKS_KEY}" | \ + /usr/sbin/cryptsetup luksOpen "${ROOT_DEV}" "${CRYPT_NAME}" --key-file - || { + msg "ERROR: Failed to activate encrypted filesystem" + return 1 + } + + # Resize filesystem to fit the encrypted device + msg "Optimizing filesystem..." + /usr/sbin/resize2fs -f "${CRYPT_DEV}" || { + msg "ERROR: Failed to optimize filesystem" + return 1 + } + + # Verify filesystem after resize + /usr/sbin/e2fsck -f -y "${CRYPT_DEV}" || { + info "WARNING: Filesystem verification had issues, but continuing" + } + + return 0 +} + +# Unlock encrypted root filesystem (subsequent boots) +unlock_encrypted_root() { + msg "Unlocking encrypted filesystem..." + + # Unseal key from TPM persistent handle + LUKS_KEY=$(tpm_unseal_key) + + if [ -z "${LUKS_KEY}" ]; then + msg "ERROR: Failed to retrieve encryption key from TPM" + msg "Attempting passphrase fallback..." + + # Try to unlock with passphrase (interactive) + /usr/sbin/cryptsetup luksOpen "${ROOT_DEV}" "${CRYPT_NAME}" || { + fatal "ERROR: Failed to unlock encrypted filesystem" + } + else + # Unlock with unsealed key + echo -n "${LUKS_KEY}" | \ + /usr/sbin/cryptsetup luksOpen "${ROOT_DEV}" "${CRYPT_NAME}" --key-file - || { + fatal "ERROR: Failed to unlock with TPM key" + } + fi + + msg "Encrypted filesystem unlocked" +} + +# Module enabled check +luksftpm_enabled() { + # Always run this module - it handles both encrypted and unencrypted cases + return 0 +} + +# Module main function +luksftpm_run() { + # Wait for storage device + if ! wait_for_device "${ROOT_DEV}" 10; then + info "Storage device not found, skipping encryption module" + return 0 + fi + + # Mount boot partition + msg "Mounting boot partition..." + mkdir -p "${BOOT_MNT}" + if ! mount "${BOOT_DEV}" "${BOOT_MNT}"; then + info "ERROR: Failed to mount boot partition, attempting standard boot..." + mkdir -p ${ROOTFS_DIR} + mount "${ROOT_DEV}" ${ROOTFS_DIR} + return 0 + fi + + # Initialize fTPM + TPM_AVAILABLE=0 + if init_ftpm; then + TPM_AVAILABLE=1 + fi + + # Check filesystem encryption status + msg "Checking filesystem encryption status..." + + MOUNT_DEV="${ROOT_DEV}" + + if /usr/sbin/cryptsetup isLuks "${ROOT_DEV}"; then + msg "Filesystem is encrypted" + unlock_encrypted_root + MOUNT_DEV="${CRYPT_DEV}" + else + msg "Filesystem is not encrypted" + + # Check if encryption is enabled and TPM is available + if [ $TPM_AVAILABLE -eq 1 ]; then + # Check for encryption marker (resume interrupted encryption) + if [ -f "${ENCRYPTION_MARKER}" ]; then + msg "Resuming interrupted encryption..." + if ! encrypt_root_filesystem; then + msg "ERROR: Failed to resume encryption" + msg "Booting without encryption..." + MOUNT_DEV="${ROOT_DEV}" + else + MOUNT_DEV="${CRYPT_DEV}" + fi + else + # First boot - perform encryption + if encrypt_root_filesystem; then + MOUNT_DEV="${CRYPT_DEV}" + else + msg "ERROR: Encryption failed - booting without encryption" + MOUNT_DEV="${ROOT_DEV}" + fi + fi + else + msg "TPM not available - skipping encryption" + MOUNT_DEV="${ROOT_DEV}" + fi + fi + + # Unmount boot partition before switching root + umount "${BOOT_MNT}" + + # Mount root filesystem to $ROOTFS_DIR (framework expects this) + msg "Mounting root filesystem..." + mkdir -p ${ROOTFS_DIR} + mount "${MOUNT_DEV}" ${ROOTFS_DIR} || { + fatal "ERROR: Failed to mount root filesystem!" + } + + # Clean up tmpfs and sensitive variables + rm -f "${TPM_PRIMARY_CTX}" "${TPM_KEY_PUB}" "${TPM_KEY_PRIV}" "${TPM_KEY_CTX}" + unset LUKS_KEY TPM_AVAILABLE MOUNT_DEV TEE_SUPPLICANT_PID + + msg "Boot complete" +} diff --git a/meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm_1.0.bb b/meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm_1.0.bb new file mode 100644 index 00000000..c0a07bde --- /dev/null +++ b/meta-ti-bsp/recipes-ti/initramfs/initramfs-module-luks-ftpm_1.0.bb @@ -0,0 +1,41 @@ +SUMMARY = "initramfs support for LUKS encryption with fTPM" +DESCRIPTION = "Provides LUKS2 full disk encryption using firmware TPM (fTPM) for key management on TI K3 platforms" + +LICENSE = "MIT" +LIC_FILES_CHKSUM = "file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420" + +# Only build this when luks-encryption feature is enabled +COMPATIBLE_MACHINE = "null" +COMPATIBLE_MACHINE:k3 = "${@bb.utils.contains('MACHINE_FEATURES', 'luks-encryption', '.*', 'null', d)}" + +FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:" + +SRC_URI = "file://luksftpm" + +do_install() { + install -d ${D}/init.d + # Install as 85-luksftpm (runs after udev at 01, before rootfs at 90) + install -m 0755 ${UNPACKDIR}/luksftpm ${D}/init.d/85-luksftpm +} + +FILES:${PN} = "/init.d/85-luksftpm" + +# Runtime dependencies +RDEPENDS:${PN} = "\ + initramfs-framework-base \ + busybox \ + kmod \ + cryptsetup \ + tpm2-tools \ + tpm2-tss \ + libtss2-tcti-device \ + optee-client \ + optee-ftpm \ + e2fsprogs-e2fsck \ + e2fsprogs-resize2fs \ + e2fsprogs-tune2fs \ + util-linux-blkid \ + kernel-module-tpm-ftpm-tee \ +" + +PACKAGE_ARCH = "${MACHINE_ARCH}" diff --git a/meta-ti-bsp/recipes-ti/initramfs/packagegroup-ti-core-initramfs.bb b/meta-ti-bsp/recipes-ti/initramfs/packagegroup-ti-core-initramfs.bb index a9eff847..9d8f0a47 100644 --- a/meta-ti-bsp/recipes-ti/initramfs/packagegroup-ti-core-initramfs.bb +++ b/meta-ti-bsp/recipes-ti/initramfs/packagegroup-ti-core-initramfs.bb @@ -22,4 +22,5 @@ RDEPENDS:${PN} += "\ initramfs-module-udev \ initramfs-module-nfsrootfs \ nfs-utils-mount \ + ${@bb.utils.contains('MACHINE_FEATURES', 'luks-encryption', 'initramfs-module-luks-ftpm', '', d)} \ " -- 2.34.1
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