[isar-cip-core][PATCH 5/9] Create an read-only rootfs with dm-verity


Quirin Gylstorff
 

From: Quirin Gylstorff <quirin.gylstorff@siemens.com>

This root file system supports SWUpdate and secure boot.
We need a writable /tmp and /var for a boot without error messages.

The mount point for /tmp is created during the systemd target
local-fs according to [1].

Before `Remount Root and Kernel File Systems.` the tmp of the initrd
is used.

[1]: https://www.freedesktop.org/software/systemd/man/systemd.special.html

Signed-off-by: Quirin Gylstorff <quirin.gylstorff@siemens.com>
---
.gitlab-ci.yml | 11 -------
Kconfig | 4 +--
classes/secure-swupdate-img.bbclass | 32 +++++++++++++++++++
kas/opt/ebg-secure-boot-snakeoil.yml | 12 ++++++-
kas/opt/ebg-snakeoil-swu.yml | 16 ----------
.../images/cip-core-image-read-only.bb | 20 ++++++++++++
recipes-core/tmp-fs/files/postinst | 3 ++
recipes-core/tmp-fs/files/tmp.mount.tmpl | 11 +++++++
recipes-core/tmp-fs/tmp-fs_0.1.bb | 26 +++++++++++++++
start-qemu.sh | 4 +++
wic/qemu-amd64-efibootguard-secureboot.wks | 11 -------
wic/qemu-amd64-efibootguard-secureboot.wks.in | 13 ++++++++
12 files changed, 122 insertions(+), 41 deletions(-)
create mode 100644 classes/secure-swupdate-img.bbclass
delete mode 100644 kas/opt/ebg-snakeoil-swu.yml
create mode 100644 recipes-core/images/cip-core-image-read-only.bb
create mode 100755 recipes-core/tmp-fs/files/postinst
create mode 100644 recipes-core/tmp-fs/files/tmp.mount.tmpl
create mode 100644 recipes-core/tmp-fs/tmp-fs_0.1.bb
delete mode 100644 wic/qemu-amd64-efibootguard-secureboot.wks
create mode 100644 wic/qemu-amd64-efibootguard-secureboot.wks.in

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 5becd37..d407f0f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -179,17 +179,6 @@ build:qemu-amd64-swupdate:
targz: disable
deploy: disable

-build:qemu-amd64-secure-boot-swu:
- extends:
- - .build_base
- variables:
- target: qemu-amd64
- extention: ebg-snakeoil-swu
- use_rt: disable
- wic_targz: disable
- targz: disable
- deploy: disable
-
# bullseye images
build:simatic-ipc227e-bullseye:
extends:
diff --git a/Kconfig b/Kconfig
index 3b882d6..e5ce257 100644
--- a/Kconfig
+++ b/Kconfig
@@ -136,11 +136,11 @@ config IMAGE_SWUPDATE
config IMAGE_SECURE_BOOT
bool "Secure boot support"
depends on TARGET_QEMU_AMD64
+ select IMAGE_SWUPDATE

config KAS_INCLUDE_SWUPDATE_SECBOOT
string
default "kas/opt/ebg-swu.yml" if IMAGE_SWUPDATE && !IMAGE_SECURE_BOOT
- default "kas/opt/ebg-secure-boot-snakeoil.yml" if !IMAGE_SWUPDATE && IMAGE_SECURE_BOOT
- default "kas/opt/ebg-snakeoil-swu.yml" if IMAGE_SWUPDATE && IMAGE_SECURE_BOOT
+ default "kas/opt/ebg-secure-boot-snakeoil.yml" if IMAGE_SECURE_BOOT

endif
diff --git a/classes/secure-swupdate-img.bbclass b/classes/secure-swupdate-img.bbclass
new file mode 100644
index 0000000..431939b
--- /dev/null
+++ b/classes/secure-swupdate-img.bbclass
@@ -0,0 +1,32 @@
+#
+# CIP Core, generic profile
+#
+# Copyright (c) Siemens AG, 2021
+#
+# Authors:
+# Quirin Gylstorff <quirin.gylstorff@siemens.com>
+#
+# SPDX-License-Identifier: MIT
+#
+
+SECURE_IMAGE_FSTYPE ?= "squashfs"
+
+inherit ${SECURE_IMAGE_FSTYPE}-img
+
+VERITY_IMAGE_TYPE = "${SECURE_IMAGE_FSTYPE}"
+
+INITRAMFS_RECIPE ?= "cip-core-initramfs"
+do_wic_image[depends] += "${INITRAMFS_RECIPE}:do_build"
+INITRD_IMAGE = "${INITRAMFS_RECIPE}-${DISTRO}-${MACHINE}.initrd.img"
+
+inherit verity-img
+inherit wic-img
+inherit extract-partition
+inherit swupdate-img
+
+SOURCE_IMAGE_FILE = "${WIC_IMAGE_FILE}"
+
+addtask do_verity_image after do_${SECURE_IMAGE_FSTYPE}_image
+addtask do_wic_image after do_verity_image
+addtask do_extract_partition after do_wic_image
+addtask do_swupdate_image after do_extract_partition
diff --git a/kas/opt/ebg-secure-boot-snakeoil.yml b/kas/opt/ebg-secure-boot-snakeoil.yml
index 2f45bde..1cfbacc 100644
--- a/kas/opt/ebg-secure-boot-snakeoil.yml
+++ b/kas/opt/ebg-secure-boot-snakeoil.yml
@@ -14,13 +14,23 @@ header:
includes:
- kas/opt/ebg-secure-boot-base.yml

+target: cip-core-image-read-only

local_conf_header:
+ swupdate: |
+ IMAGE_INSTALL_append = " swupdate"
+ IMAGE_INSTALL_append = " swupdate-handler-roundrobin"
+
+ verity-img: |
+ SECURE_IMAGE_FSTYPE = "squashfs"
+ VERITY_IMAGE_RECIPE = "cip-core-image-read-only"
+ IMAGE_TYPE = "secure-swupdate-img"
+ WKS_FILE = "${MACHINE}-efibootguard-secureboot.wks.in"
+
secure-boot: |
# Add snakeoil and ovmf binaries for qemu
IMAGER_BUILD_DEPS += "ebg-secure-boot-snakeoil ovmf-binaries"
IMAGER_INSTALL += "ebg-secure-boot-snakeoil"
- WKS_FILE = "${MACHINE}-efibootguard-secureboot.wks"

ovmf: |
# snakeoil certs are only part of backports
diff --git a/kas/opt/ebg-snakeoil-swu.yml b/kas/opt/ebg-snakeoil-swu.yml
deleted file mode 100644
index 2f15c0e..0000000
--- a/kas/opt/ebg-snakeoil-swu.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-#
-# CIP Core, generic profile
-#
-# Copyright (c) Siemens AG, 2021
-#
-# Authors:
-# Quirin Gylstorff <quirin.gylstorff@siemens.com>
-#
-# SPDX-License-Identifier: MIT
-#
-
-header:
- version: 10
- includes:
- - kas/opt/ebg-secure-boot-snakeoil.yml
- - kas/opt/swupdate.yml
diff --git a/recipes-core/images/cip-core-image-read-only.bb b/recipes-core/images/cip-core-image-read-only.bb
new file mode 100644
index 0000000..7ef2dc2
--- /dev/null
+++ b/recipes-core/images/cip-core-image-read-only.bb
@@ -0,0 +1,20 @@
+require cip-core-image.bb
+
+SQUASHFS_EXCLUDE_DIRS += "home var"
+
+IMAGE_INSTALL += "tmp-fs"
+IMAGE_INSTALL_remove += "initramfs-abrootfs-secureboot"
+
+image_configure_fstab() {
+ sudo tee '${IMAGE_ROOTFS}/etc/fstab' << EOF
+# Begin /etc/fstab
+/dev/root / auto defaults,ro 0 0
+LABEL=var /var auto defaults 0 0
+proc /proc proc nosuid,noexec,nodev 0 0
+sysfs /sys sysfs nosuid,noexec,nodev 0 0
+devpts /dev/pts devpts gid=5,mode=620 0 0
+tmpfs /run tmpfs nodev,nosuid,size=500M,mode=755 0 0
+devtmpfs /dev devtmpfs mode=0755,nosuid 0 0
+# End /etc/fstab
+EOF
+}
diff --git a/recipes-core/tmp-fs/files/postinst b/recipes-core/tmp-fs/files/postinst
new file mode 100755
index 0000000..07017fd
--- /dev/null
+++ b/recipes-core/tmp-fs/files/postinst
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+deb-systemd-helper enable tmp.mount || true
diff --git a/recipes-core/tmp-fs/files/tmp.mount.tmpl b/recipes-core/tmp-fs/files/tmp.mount.tmpl
new file mode 100644
index 0000000..fcb2f3e
--- /dev/null
+++ b/recipes-core/tmp-fs/files/tmp.mount.tmpl
@@ -0,0 +1,11 @@
+[Unit]
+Description=Create /tmp
+
+[Mount]
+What=tmpfs
+Where=/tmp
+Type=tmpfs
+Options=${TMP_OPTIONS}
+
+[Install]
+WantedBy=local-fs.target
diff --git a/recipes-core/tmp-fs/tmp-fs_0.1.bb b/recipes-core/tmp-fs/tmp-fs_0.1.bb
new file mode 100644
index 0000000..3ec20c7
--- /dev/null
+++ b/recipes-core/tmp-fs/tmp-fs_0.1.bb
@@ -0,0 +1,26 @@
+#
+# CIP Core, generic profile
+#
+# Copyright (c) Siemens AG, 2021
+#
+# Authors:
+# Quirin Gylstorff <quirin.gylstorff@siemens.com>
+#
+# SPDX-License-Identifier: MIT
+
+inherit dpkg-raw
+
+SRC_URI = "file://postinst \
+ file://tmp.mount.tmpl"
+
+TMP_FS_SIZE ?= "500M"
+TMP_FS_MODE ?= "755"
+TMP_FS_OPTIONS = "nodev,nosuid,size=${TMP_SIZE},mode=${TMP_MODE}"
+
+TEMPLATE_FILES = "tmp.mount.tmpl"
+TEMPLATE_VARS += "TMP_FS_OPTIONS"
+
+do_install[cleandirs]+="${D}/lib/systemd/system"
+do_install() {
+ install -m 0644 ${WORKDIR}/tmp.mount ${D}/lib/systemd/system/tmp.mount
+}
diff --git a/start-qemu.sh b/start-qemu.sh
index a92e9f4..c700974 100755
--- a/start-qemu.sh
+++ b/start-qemu.sh
@@ -42,6 +42,9 @@ if [ -z "${TARGET_IMAGE}" ];then
TARGET_IMAGE="cip-core-image"
if grep -s -q "IMAGE_SECURITY: true" .config.yaml; then
TARGET_IMAGE="cip-core-image-security"
+ fi
+ if [ -n "${SECURE_BOOT}" ]; then
+ TARGET_IMAGE="cip-core-image-read-only"
fi
fi

@@ -55,6 +58,7 @@ case "$1" in
-machine q35,accel=kvm:tcg \
-device virtio-net-pci,netdev=net"
if [ -n "${SECURE_BOOT}" ]; then
+ # set bootindex=0 to boot disk instead of EFI-shell
QEMU_EXTRA_ARGS=" \
${QEMU_EXTRA_ARGS} -device ide-hd,drive=disk,bootindex=0"
else
diff --git a/wic/qemu-amd64-efibootguard-secureboot.wks b/wic/qemu-amd64-efibootguard-secureboot.wks
deleted file mode 100644
index ff351db..0000000
--- a/wic/qemu-amd64-efibootguard-secureboot.wks
+++ /dev/null
@@ -1,11 +0,0 @@
-# short-description: Qemu-amd64 with Efibootguard and SWUpdate
-# long-description: Disk image for qemu-amd64 with EFI Boot Guard and SWUpdate
-include ebg-signed-bootloader.inc
-
-# EFI Boot Guard environment/config partitions plus Kernel files
-part --source efibootguard-boot --ondisk sda --size 32M --extra-space 0 --overhead-factor 1 --label BOOT0 --align 1024 --part-type=0700 --sourceparams "revision=2,unified-kernel=y,signwith=/usr/bin/sign_secure_image.sh"
-part --source efibootguard-boot --ondisk sda --size 32M --extra-space 0 --overhead-factor 1 --label BOOT1 --align 1024 --part-type=0700 --sourceparams "revision=1,unified-kernel=y,signwith=/usr/bin/sign_secure_image.sh"
-
-include swupdate-partition.inc
-
-bootloader --ptable gpt --append="console=tty0 console=ttyS0,115200 rootwait earlyprintk panic=0"
diff --git a/wic/qemu-amd64-efibootguard-secureboot.wks.in b/wic/qemu-amd64-efibootguard-secureboot.wks.in
new file mode 100644
index 0000000..c4ea0c8
--- /dev/null
+++ b/wic/qemu-amd64-efibootguard-secureboot.wks.in
@@ -0,0 +1,13 @@
+# EFI partition containing efibootguard bootloader binary
+part --source efibootguard-efi --ondisk sda --size 16M --extra-space 0 --overhead-factor 1 --label efi --align 1024 --part-type=EF00 --active --sourceparams "signwith=/usr/bin/sign_secure_image.sh"
+
+# EFI Boot Guard environment/config partitions plus Kernel files
+part --source efibootguard-boot --ondisk sda --size 32M --extra-space 0 --overhead-factor 1 --label BOOT0 --align 1024 --part-type=0700 --sourceparams "revision=2,unified-kernel=y,signwith=/usr/bin/sign_secure_image.sh"
+part --source efibootguard-boot --ondisk sda --size 32M --extra-space 0 --overhead-factor 1 --label BOOT1 --align 1024 --part-type=0700 --sourceparams "revision=1,unified-kernel=y,signwith=/usr/bin/sign_secure_image.sh"
+
+part --source rawcopy --sourceparams "file=${IMAGE_FULLNAME}.${VERITY_IMAGE_TYPE}.verity.img" --ondisk sda --align 1024 --fixed-size 1G --uuid "fedcba98-7654-3210-cafe-5e0710000001"
+part --source rawcopy --sourceparams "file=${IMAGE_FULLNAME}.${VERITY_IMAGE_TYPE}.verity.img" --ondisk sda --align 1024 --fixed-size 1G --uuid "fedcba98-7654-3210-cafe-5e0710000002"
+
+part /var --source rootfs --rootfs-dir=${IMAGE_ROOTFS}/var --ondisk sda --fstype=ext4 --label var --align 1024 --size 2G
+
+bootloader --ptable gpt --append="console=tty0 console=ttyS0,115200 rootwait rw earlyprintk"
--
2.30.2

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