flatcar-scripts/build_kernel_image.sh
Luigi Semenzato 195aebeaea Add tpm_tis module configuration options in preparation for linking with kernel
We need to set these options in order to link the TPM driver in the kernel before we fix the PNP table in the firmware.  This is the least disruptive change that makes the TPM available earlier in the boot sequence.

Change-Id: I729cd7c153507200e177895bae01951e97b70968

BUG=none
TEST=rebuilt kernel, reinstalled, booted, verified that tcsd still runs

Review URL: http://codereview.chromium.org/3969001
2010-10-20 17:35:00 -07:00

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#!/bin/bash
# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
# Helper script that generates the signed kernel image
. "$(dirname "$0")/common.sh"
get_default_board
# Flags.
DEFINE_string arch "x86" \
"The boot architecture: arm or x86. (Default: x86)"
DEFINE_string to "/tmp/vmlinuz.image" \
"The path to the kernel image to be created. (Default: /tmp/vmlinuz.image)"
DEFINE_string hd_vblock "/tmp/vmlinuz_hd.vblock" \
"The path to the installed kernel's vblock (Default: /tmp/vmlinuz_hd.vblock)"
DEFINE_string vmlinuz "vmlinuz" \
"The path to the kernel (Default: vmlinuz)"
DEFINE_string working_dir "/tmp/vmlinuz.working" \
"Working directory for in-progress files. (Default: /tmp/vmlinuz.working)"
DEFINE_boolean keep_work ${FLAGS_FALSE} \
"Keep temporary files (*.keyblock, *.vbpubk). (Default: false)"
DEFINE_string keys_dir "${SRC_ROOT}/platform/vboot_reference/tests/testkeys" \
"Directory with the RSA signing keys. (Defaults to test keys)"
DEFINE_boolean use_dev_keys ${FLAGS_FALSE} \
"Use developer keys for signing. (Default: false)"
# Note, to enable verified boot, the caller would manually pass:
# --boot_args='dm="... /dev/sd%D%P /dev/sd%D%P ..." \
# --root=/dev/dm-0
DEFINE_string boot_args "noinitrd" \
"Additional boot arguments to pass to the commandline (Default: noinitrd)"
DEFINE_string root "/dev/sd%D%P" \
"Expected device root (Default: root=/dev/sd%D%P)"
# If provided, will automatically add verified boot arguments.
DEFINE_string rootfs_image "" \
"Optional path to the rootfs device or image.(Default: \"\")"
DEFINE_string rootfs_hash "" \
"Optional path to output the rootfs hash to. (Default: \"\")"
DEFINE_integer verity_error_behavior 2 \
"Verified boot error behavior [0: I/O errors, 1: reboot, 2: nothing] \
(Default: 2)"
DEFINE_integer verity_tree_depth 1 \
"Optional Verified boot hash tree depth. (Default: 1)"
DEFINE_integer verity_max_ios 1024 \
"Optional number of outstanding I/O operations. (Default: 1024)"
DEFINE_string verity_hash_alg "sha1" \
"Cryptographic hash algorithm used for dm-verity. (Default: sha1)"
# Parse flags
FLAGS "$@" || exit 1
eval set -- "${FLAGS_ARGV}"
# Die on error
set -e
verity_args=
# Even with a rootfs_image, root= is not changed unless specified.
if [[ -n "${FLAGS_rootfs_image}" && -n "${FLAGS_rootfs_hash}" ]]; then
# Gets the number of blocks. 4096 byte blocks _are_ expected.
root_fs_blocks=$(sudo dumpe2fs "${FLAGS_rootfs_image}" 2> /dev/null |
grep "Block count" |
tr -d ' ' |
cut -f2 -d:)
root_fs_block_sz=$(sudo dumpe2fs "${FLAGS_rootfs_image}" 2> /dev/null |
grep "Block size" |
tr -d ' ' |
cut -f2 -d:)
info "rootfs is ${root_fs_blocks} blocks of ${root_fs_block_sz} bytes"
if [[ ${root_fs_block_sz} -ne 4096 ]]; then
error "Root file system blocks are not 4k!"
fi
info "Generating root fs hash tree."
# Runs as sudo in case the image is a block device.
table=$(sudo verity create ${FLAGS_verity_tree_depth} \
${FLAGS_verity_hash_alg} \
${FLAGS_rootfs_image} \
${root_fs_blocks} \
${FLAGS_rootfs_hash})
if [[ -f "${FLAGS_rootfs_hash}" ]]; then
sudo chmod a+r "${FLAGS_rootfs_hash}"
fi
# Don't claim the root device unless the root= flag is pointed to
# the verified boot device. Doing so will claim /dev/sdDP out from
# under the system.
if [[ ${FLAGS_root} = "/dev/dm-0" ]]; then
if [[ "${FLAGS_arch}" = "x86" ]]; then
base_root='/dev/sd%D%P'
elif [[ "${FLAGS_arch}" = "arm" ]]; then
base_root='/dev/${devname}${rootpart}'
fi
table=${table//HASH_DEV/${base_root}}
table=${table//ROOT_DEV/${base_root}}
fi
verity_args="dm=\"vroot none ro,${table}\""
info "dm-verity configuration: ${verity_args}"
fi
mkdir -p "${FLAGS_working_dir}"
# Only let dm-verity block if rootfs verification is configured.
dev_wait=0
if [[ ${FLAGS_root} = "/dev/dm-0" ]]; then
dev_wait=1
fi
cat <<EOF > "${FLAGS_working_dir}/boot.config"
root=${FLAGS_root}
dm_verity.error_behavior=${FLAGS_verity_error_behavior}
dm_verity.max_bios=${FLAGS_verity_max_ios}
dm_verity.dev_wait=${dev_wait}
${verity_args}
${FLAGS_boot_args}
EOF
WORK="${WORK} ${FLAGS_working_dir}/boot.config"
info "Emitted cross-platform boot params to ${FLAGS_working_dir}/boot.config"
# FIXME: At the moment, we're working on signed images for x86 only. ARM will
# support this before shipping, but at the moment they don't.
if [[ "${FLAGS_arch}" = "x86" ]]; then
# Legacy BIOS will use the kernel in the rootfs (via syslinux), as will
# standard EFI BIOS (via grub, from the EFI System Partition). Chrome OS
# BIOS will use a separate signed kernel partition, which we'll create now.
# FIXME: remove serial output, debugging messages.
mkdir -p ${FLAGS_working_dir}
cat <<EOF | cat - "${FLAGS_working_dir}/boot.config" \
> "${FLAGS_working_dir}/config.txt"
earlyprintk=serial,ttyS0,115200
console=ttyS0,115200
init=/sbin/init
add_efi_memmap
boot=local
rootwait
ro
noresume
noswap
i915.modeset=1
loglevel=7
cros_secure
kern_guid=%U
tpm_tis.force=1
tpm_tis.interrupts=0
EOF
WORK="${WORK} ${FLAGS_working_dir}/config.txt"
# We sign the image with the recovery_key, because this is what goes onto the
# USB key. We can only boot from the USB drive in recovery mode.
# For dev install shim, we need to use the installer keyblock instead of
# the recovery keyblock because of the difference in flags.
if [ ${FLAGS_use_dev_keys} -eq ${FLAGS_TRUE} ]; then
USB_KEYBLOCK=installer_kernel.keyblock
info "DEBUG: use dev install signing key"
else
USB_KEYBLOCK=recovery_kernel.keyblock
info "DEBUG: use recovery signing key"
fi
# Create and sign the kernel blob
vbutil_kernel \
--pack "${FLAGS_to}" \
--keyblock "${FLAGS_keys_dir}/${USB_KEYBLOCK}" \
--signprivate "${FLAGS_keys_dir}/recovery_kernel_data_key.vbprivk" \
--version 1 \
--config "${FLAGS_working_dir}/config.txt" \
--bootloader /lib64/bootstub/bootstub.efi \
--vmlinuz "${FLAGS_vmlinuz}"
# And verify it.
vbutil_kernel \
--verify "${FLAGS_to}" \
--signpubkey "${FLAGS_keys_dir}/recovery_key.vbpubk"
# Now we re-sign the same image using the normal keys. This is the kernel
# image that is put on the hard disk by the installer. Note: To save space on
# the USB image, we're only emitting the new verfication block, and the
# installer just replaces that part of the hard disk's kernel partition.
vbutil_kernel \
--repack "${FLAGS_hd_vblock}" \
--vblockonly \
--keyblock "${FLAGS_keys_dir}/kernel.keyblock" \
--signprivate "${FLAGS_keys_dir}/kernel_data_key.vbprivk" \
--oldblob "${FLAGS_to}"
# To verify it, we have to replace the vblock from the original image.
tempfile=$(mktemp)
trap "rm -f $tempfile" EXIT
cat "${FLAGS_hd_vblock}" > $tempfile
dd if="${FLAGS_to}" bs=65536 skip=1 >> $tempfile
vbutil_kernel \
--verify $tempfile \
--signpubkey "${FLAGS_keys_dir}/kernel_subkey.vbpubk"
rm -f $tempfile
trap - EXIT
elif [[ "${FLAGS_arch}" = "arm" ]]; then
# FIXME: This stuff is unsigned, and will likely change with vboot_reference
# but it doesn't technically have to.
kernel_script="${FLAGS_working_dir}/kernel.scr"
kernel_script_img="${FLAGS_working_dir}/kernel.scr.uimg"
# HACK: !! Kernel image construction requires some stuff from portage, not
# sure how to get that information here cleanly !!
kernel_image="${FLAGS_vmlinuz/vmlinuz/vmlinux.uimg}"
WORK="${WORK} ${kernel_script} ${kernel_script_img}"
kernel_size=$((($(stat -c %s "${kernel_image}") + 511) / 512))
script_size=16
# Build boot script image
echo -n 'setenv bootargs ${bootargs} ' > "${kernel_script}"
tr '\n' ' ' <"${FLAGS_working_dir}/boot.config" >> "${kernel_script}"
echo >> "${kernel_script}"
printf 'read ${devtype} 0:${kernelpart} ${loadaddr} %x %x\n' \
${script_size} ${kernel_size} >> "${kernel_script}"
echo 'bootm ${loadaddr}' >> ${kernel_script}
mkimage -A arm -O linux -T script -C none -a 0 -e 0 \
-n kernel_script -d "${kernel_script}" "${kernel_script_img}"
if [ $(stat -c %s "${kernel_script_img}") -gt $((512 * ${script_size})) ]
then
echo 'Kernel script too large for reserved space.'
exit 1
fi
# Assemble image
rm -f "${FLAGS_to}"
dd if="${kernel_script_img}" of="${FLAGS_to}" bs=512 count="${script_size}"
dd if="${kernel_image}" of="${FLAGS_to}" bs=512 seek="${script_size}"
# TODO: HACK: Until the kernel partition contains a signed image, create a
# phony hd.vblock to keep chromeos-install and cros_generate_update_payload
# working.
dd if="${FLAGS_to}" of="${FLAGS_hd_vblock}" bs=64K count=1
else
error "Unknown arch: ${FLAGS_arch}"
fi
set +e # cleanup failure is a-ok
if [[ ${FLAGS_keep_work} -eq ${FLAGS_FALSE} ]]; then
info "Cleaning up temporary files: ${WORK}"
rm ${WORK}
rmdir ${FLAGS_working_dir}
fi
info "Kernel partition image emitted: ${FLAGS_to}"
if [[ -f ${FLAGS_rootfs_hash} ]]; then
info "Root filesystem hash emitted: ${FLAGS_rootfs_hash}"
fi