From: Gylstorff Quirin <quirin.gylstorff@siemens.com>
To: Jan Kiszka <jan.kiszka@siemens.com>,
cip-dev@lists.cip-project.org, christian.storm@siemens.com
Subject: Re: [cip-dev][isar-cip-core][RFC v2 4/7] Add initramfs hook to encrypt a partition
Date: Fri, 17 Feb 2023 16:06:31 +0100 [thread overview]
Message-ID: <00766d63-d1cc-c792-c5bd-8c7d4a3778d4@siemens.com> (raw)
In-Reply-To: <2012e77d-1892-1797-3161-b834ccebda86@siemens.com>
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On 2/17/23 15:53, Jan Kiszka wrote:
> On 17.02.23 14:05, Quirin Gylstorff wrote:
>> From: Quirin Gylstorff <quirin.gylstorff@siemens.com>
>>
>> This creates a new luks encrypted ext4 partition with a the
>> key stored in the tpm2.
>>
>> The initial key is randomly generated and removed from the
>> LUKS partition. Therefore a new key cannot be added by the user
>> and if the LUKS header is corrupted the data is no longer readable.
>>
>> Signed-off-by: Quirin Gylstorff <quirin.gylstorff@siemens.com>
>> ---
>> .../files/encrypt_partition.env.tmpl | 2 +
>> .../files/encrypt_partition.hook | 49 +++++++
>> .../files/encrypt_partition.script | 135 ++++++++++++++++++
>> .../initramfs-crypt-hook_0.1.bb | 37 +++++
>> wic/x86-efibootguard.wks.in | 4 +-
>> 5 files changed, 225 insertions(+), 2 deletions(-)
>> create mode 100644 recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.env.tmpl
>> create mode 100644 recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.hook
>> create mode 100644 recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.script
>> create mode 100644 recipes-initramfs/initramfs-crypt-hook/initramfs-crypt-hook_0.1.bb
>>
>> diff --git a/recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.env.tmpl b/recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.env.tmpl
>> new file mode 100644
>> index 0000000..943fe4b
>> --- /dev/null
>> +++ b/recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.env.tmpl
>> @@ -0,0 +1,2 @@
>> +PARTITIONS="${CRYPT_PARTITIONS}"
>> +REDUDUCE_DEVICE_SIZE="${CRYPT_REDUDUCE_DEVICE_SIZE}"
>
> Did you mean "REDUCE"?
That was my intenion will fix it in v3.
>
> And what is this variable for?
If you use online reencryption on a populated partition you need to
create the space for the LUKS header. The necessary minimum size is 32MB.
As an alternative you can detach the LUKS header.
>
>> diff --git a/recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.hook b/recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.hook
>> new file mode 100644
>> index 0000000..96e084a
>> --- /dev/null
>> +++ b/recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.hook
>> @@ -0,0 +1,49 @@
>> +#!/bin/sh
>> +# Copyright (C) Siemens AG, 2020-2022
>> +#
>> +# SPDX-License-Identifier: MIT
>> +
>> +PREREQ=""
>> +
>> +prereqs()
>> +{
>> + echo "$PREREQ"
>> +}
>> +
>> +case $1 in
>> +prereqs)
>> + prereqs
>> + exit 0
>> + ;;
>> +esac
>> +
>> +. /usr/share/initramfs-tools/scripts/functions
>> +. /usr/share/initramfs-tools/hook-functions
>> +
>> +manual_add_modules tpm
>> +manual_add_modules tpm_tis_core
>> +manual_add_modules tpm_tis
>> +manual_add_modules tpm_crb
>> +manual_add_modules dm_mod
>> +manual_add_modules dm_crypt
>> +
>> +copy_exec /usr/bin/openssl
>> +copy_exec /usr/sbin/mke2fs
>> +copy_exec /usr/bin/grep
>> +copy_exec /usr/bin/awk
>> +copy_exec /usr/bin/expr
>> +copy_exec /usr/sbin/e2fsck
>> +copy_exec /usr/sbin/resize2fs
>> +copy_exec /usr/sbin/cryptsetup
>> +copy_exec /usr/bin/systemd-cryptenroll
>> +copy_exec /usr/lib/systemd/systemd-cryptsetup
>> +
>> +if [ -x cryptsetup-reencrypt ]; then
>> + copy_exec /usr/sbin/cryptsetup-reencrypt
>> +fi
>> +
>> +for _LIBRARY in /usr/lib/*/libtss2*; do
>> + copy_exec "$_LIBRARY"
>> +done
>> +
>> +copy_file library /usr/share/encrypt_partition/encrypt_partition.env /usr/share/encrypt_partition/encrypt_partition.env
>> diff --git a/recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.script b/recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.script
>> new file mode 100644
>> index 0000000..e58794e
>> --- /dev/null
>> +++ b/recipes-initramfs/initramfs-crypt-hook/files/encrypt_partition.script
>> @@ -0,0 +1,135 @@
>> +#!/bin/sh
>> +#
>> +# CIP Core, generic profile
>> +#
>> +# Copyright (c) Siemens AG, 2023
>> +#
>> +# Authors:
>> +# Quirin Gylstorff <quirin.gylstorff@siemens.com>
>> +#
>> +# SPDX-License-Identifier: MIT
>> +prereqs()
>> +{
>> + # Make sure that this script is run last in local-top
>> + local req
>> + for req in "${0%/*}"/*; do
>> + script="${req##*/}"
>> + if [ "$script" != "${0##*/}" ]; then
>> + printf '%s\n' "$script"
>> + fi
>> + done
>> +}
>> +case $1 in
>> +prereqs)
>> + prereqs
>> + exit 0
>> + ;;
>> +esac
>> +
>> +. /scripts/functions
>> +
>> +# get configuration variables
>> +. /usr/share/encrypt_partition/encrypt_partition.env
>> +
>> +# load necessary kernel modules:
>> +modprobe tpm_tis
>> +modprobe tpm_crb
>> +
>> +# fixed tpm device or do we need to find it
>> +tpm_device=/dev/tpmrm0
>> +partition_sets="$PARTITIONS"
>> +
>> +open_tpm2_partition() {
>> + if ! /usr/lib/systemd/systemd-cryptsetup attach "$crypt_mount_name" \
>> + "$1" - tpm2-device="$tpm_device"; then
>> + panic "Can't decrypt '$1' !"
>> + fi
>> +}
>> +
>> +enroll_tpm2_token() {
>> + #check systemd version and export password if necessary
>> + if [ -x /usr/bin/systemd-cryptenroll ]; then
>
> And if that file does not exist? No error? No bail-out?
>
I will remove that check and move it to the hook and fail during build
time. Is that better?
>> + systemd_version=$(systemd-cryptenroll --version | \
>> + awk -F " " 'NR==1{print $2 }')
>> + #check systemd version and export password if necessary
>> + if [ "$systemd_version" -ge "251" ]; then
>> + PASSWORD=$(cat "$2" )
>> + export PASSWORD
>> + /usr/bin/systemd-cryptenroll --tpm2-device="$tpm_device" \
>> + --tpm2-pcrs=7 "$1"
>> + PASSWORD=
>> + else
>> + panic "Unknown systemd version: '$systemd_version'!"
>> + fi
>> + fi
>> +}
>> +
>> +reencrypt_existing_partition() {
>> + part_device=$(readlink -f "$partition")
>> + part_size_blocks=$(cat /sys/class/block/"$(awk -v dev=$part_device 'BEGIN{split(dev,a,"/"); print a[3]}' )"/size)
>> + reduced_size=$(expr $part_size_blocks - 65536 )
>> + reduced_size_in_byte=$(expr $reduced_size \* 512)
>> + reduced_size_in_kb=$(expr $reduced_size_in_byte / 1024)K
>> + resize2fs "$1" "$reduced_size_in_kb"
>> + if [ -x cryptsetup-reencrypt ]; then
>> + /usr/sbin/cryptsetup-reencrypt --new --reduce-device-size "${REDUDUCE_DEVICE_SIZE}" $1 < $2
>> + else
>> + /usr/sbin/cryptsetup reencrypt --encrypt --reduce-device-size "${REDUDUCE_DEVICE_SIZE}" $1 < $2
>> + fi
>> +
>> +}
>> +
>> +
>
> One newline should be enough here.
Will fix in v3.
>
>> +if [ ! -e "$tpm_device" ]; then
>> + panic "tpm device '$tpm_device' does not exists - cannot create a encrypted device!"
>> +fi
>> +
>> +for partition_set in $partition_sets; do
>> + partition_label=$(awk -v var=$partition_set 'BEGIN{split(var,a,":"); print a[1]}')
>> + partition_mountpoint=$(awk -v var=$partition_set 'BEGIN{split(var,a,":"); print a[2]}')
>> + partition_format=$(awk -v var=$partition_set 'BEGIN{split(var,a,":"); print a[3]}')
>> + partition=/dev/disk/by-partlabel/$partition_label
>> + crypt_mount_name="encrypted_$partition_label"
>> + decrypted_part=/dev/mapper/"$crypt_mount_name"
>> +
>> + # check if partition is already encrypted with systemd-tpm2
>> + if /usr/sbin/cryptsetup luksDump --batch-mode "$partition" \
>> + | grep -q "systemd-tpm2"; then
>> + open_tpm2_partition "$partition"
>> + if ! mount -t $(get_fstype "${decrypted_part}") "${decrypted_part}" "${rootmnt}${partition_mountpoint}"; then
>> + panic "Can't mount encrypted partition '${decrypted_part}'!"
>> + fi
>> + continue
>> + fi
>> +
>> + # create random password for initial encryption
>> + # this will be dropped after reboot
>> + tmp_key=/tmp/"$partition_label-lukskey"
>> + openssl rand -base64 32 > "$tmp_key"
>> +
>> + case "${partition_format}" in
>> + "reencrypt")
>> + reencrypt_existing_partition "$partition" "$tmp_key"
>> + enroll_tpm2_token "$partition" "$tmp_key"
>> + open_tpm2_partition "$partition"
>> + ;;
>> + "format")
>> + /usr/sbin/cryptsetup luksFormat --batch-mode \
>> + --type luks2 "$partition" < "$tmp_key"
>> + enroll_tpm2_token "$partition" "$tmp_key"
>> + open_tpm2_partition_tpm2_partition "$partition"
>> + mke2fs -t ext4 "${decrypted_part}"
>
> We likely want to make this line configurable at recipe-level, both
> regarding fs options as well as the fs type itself.
I will add an additional field to the configuration string.
>
>> + ;;
>> + *)
>> + panic "Unknown value ${partition_format}. Cannot create a encrypted partition !"
>> + ;;
>> + esac
>> +
>> + if ! mount -t $(get_fstype "${decrypted_part}") "${decrypted_part}" "${rootmnt}${partition_mountpoint}"; then
>> + panic "Can't mount encrypted partition '${decrypted_part}'!"
>> + fi
>> +
>> + # delete initial key
>> + # afterwards no new keys can be enrolled
>> + /usr/bin/systemd-cryptenroll "$partition" --wipe-slot=0
>> +done
>> diff --git a/recipes-initramfs/initramfs-crypt-hook/initramfs-crypt-hook_0.1.bb b/recipes-initramfs/initramfs-crypt-hook/initramfs-crypt-hook_0.1.bb
>> new file mode 100644
>> index 0000000..ba2b884
>> --- /dev/null
>> +++ b/recipes-initramfs/initramfs-crypt-hook/initramfs-crypt-hook_0.1.bb
>> @@ -0,0 +1,37 @@
>> +#
>> +# CIP Core, generic profile
>> +#
>> +# Copyright (c) Siemens AG, 2020-2022
>> +#
>> +# Authors:
>> +# Quirin Gylstorff <quirin.gylstorff@siemens.com>
>> +#
>> +# SPDX-License-Identifier: MIT
>> +
>> +
>> +inherit dpkg-raw
>> +
>> +DEBIAN_DEPENDS = "initramfs-tools, cryptsetup, systemd(>= 251), \
>> + awk, openssl, libtss2-esys-3.0.2-0, libtss2-rc0, libtss2-mu0, e2fsprogs"
>> +
>> +SRC_URI += "file://encrypt_partition.hook \
>> + file://encrypt_partition.script \
>> + file://encrypt_partition.env.tmpl"
>> +
>> +CRYPT_PARTITIONS ??= "home:/home:reencrypt var:/var:reencrypt"
>> +CRYPT_REDUDUCE_DEVICE_SIZE="32M"
>> +
>> +TEMPLATE_VARS = "CRYPT_PARTITIONS CRYPT_REDUDUCE_DEVICE_SIZE"
>> +TEMPLATE_FILES = "encrypt_partition.env.tmpl"
>> +
>> +do_install[cleandirs] += " \
>> + ${D}/usr/share/initramfs-tools/hooks \
>> + ${D}/usr/share/encrypt_partition \
>> + ${D}/usr/share/initramfs-tools/scripts/local-bottom"
>> +do_install() {
>> + install -m 0600 "${WORKDIR}/encrypt_partition.env" "${D}/usr/share/encrypt_partition/encrypt_partition.env"
>> + install -m 0755 "${WORKDIR}/encrypt_partition.script" \
>> + "${D}/usr/share/initramfs-tools/scripts/local-bottom/encrypt_partition"
>> + install -m 0755 "${WORKDIR}/encrypt_partition.hook" \
>> + "${D}/usr/share/initramfs-tools/hooks/encrypt_partition"
>> +}
>> diff --git a/wic/x86-efibootguard.wks.in b/wic/x86-efibootguard.wks.in
>> index b635a8b..1d29583 100644
>> --- a/wic/x86-efibootguard.wks.in
>> +++ b/wic/x86-efibootguard.wks.in
>> @@ -7,7 +7,7 @@ part --source rawcopy --sourceparams "file=${IMAGE_FULLNAME}.squashfs" --align 1
>> part --source empty --align 1024 --fixed-size 1G --uuid "${ABROOTFS_PART_UUID_B}"
>>
>> # home and var are extra partitions
>> -part /home --source rootfs --rootfs-dir=${IMAGE_ROOTFS}/home --fstype=ext4 --label home --align 1024 --size 1G
>> -part /var --source rootfs --rootfs-dir=${IMAGE_ROOTFS}/var --fstype=ext4 --label var --align 1024 --size 2G
>> +part /home --source rootfs --rootfs-dir=${IMAGE_ROOTFS}/home --fstype=ext4 --label home --align 1024 --size 1G --extra-space=100M
>> +part /var --source rootfs --rootfs-dir=${IMAGE_ROOTFS}/var --fstype=ext4 --label var --align 1024 --size 2G --extra-space=100M
>>
>> bootloader --ptable gpt --append="console=tty0 console=ttyS0,115200 rootwait earlyprintk"
>
> Jan
>
Thanks for the review
Quirin
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next prev parent reply other threads:[~2023-02-17 15:07 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-17 13:05 [cip-dev][isar-cip-core][RFC v2 0/7] Encrypt Partition in initramfs Quirin Gylstorff
2023-02-17 13:05 ` [cip-dev][isar-cip-core][RFC v2 1/7] linux-cip: update kernel configuration for tpm2 support Quirin Gylstorff
2023-02-17 13:05 ` [cip-dev][isar-cip-core][RFC v2 2/7] use bullseye backports for systemd-cryptenroll Quirin Gylstorff
2023-02-18 8:04 ` Moessbauer, Felix
2023-02-17 13:05 ` [cip-dev][isar-cip-core][RFC v2 3/7] start-qemu: If swtpm is available create a tpm2 device Quirin Gylstorff
2023-02-17 14:49 ` Jan Kiszka
2023-02-17 15:11 ` Gylstorff Quirin
2023-02-17 13:05 ` [cip-dev][isar-cip-core][RFC v2 4/7] Add initramfs hook to encrypt a partition Quirin Gylstorff
2023-02-17 14:53 ` Jan Kiszka
2023-02-17 15:06 ` Gylstorff Quirin [this message]
2023-02-17 15:10 ` Jan Kiszka
2023-02-17 15:20 ` Gylstorff Quirin
2023-02-18 8:10 ` Moessbauer, Felix
2023-02-22 16:30 ` Gylstorff Quirin
2023-02-17 13:05 ` [cip-dev][isar-cip-core][RFC v2 5/7] overlay: add prerequisite 'encrypt_partition' Quirin Gylstorff
2023-02-17 13:05 ` [cip-dev][isar-cip-core][RFC v2 6/7] KConfig: add tpm option Quirin Gylstorff
2023-02-17 13:05 ` [cip-dev][isar-cip-core][RFC v2 7/7] .gitlabci: Add ci build Quirin Gylstorff
2023-02-17 14:55 ` Jan Kiszka
2023-02-17 14:59 ` Gylstorff Quirin
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