From patchwork Thu Mar 20 07:43:07 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudius Heine X-Patchwork-Id: 14023487 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BB5CC36001 for ; Thu, 20 Mar 2025 07:43:26 +0000 (UTC) Received: from mx.denx.de (mx.denx.de [89.58.32.78]) by mx.groups.io with SMTP id smtpd.web11.2370.1742456603249312751 for ; Thu, 20 Mar 2025 00:43:23 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@denx.de header.s=mx-20241105 header.b=ba9+Wb8e; spf=pass (domain: denx.de, ip: 89.58.32.78, mailfrom: ch@denx.de) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 601FC101E91CA; Thu, 20 Mar 2025 08:43:21 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=mx-20241105; t=1742456601; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=pS54Bl/DWjS1hhUTL+Gr8Rk9RJbScOGvZFL0TXK2ZS0=; b=ba9+Wb8eXf3k6+KhTqsF3oUouopa9n/CltuqIvXC4uK3xA+6h2uWPhu7k2Ci0ruP5d15N+ dqfdym/RReOfkboeD7rafLqxSMxhjivDxZrEEbVVp2CXawpIlcX41A6irsRDYbX1h7iZ3I yMY64nkexd3lFF5Lp6L6JOe/mEBQzQqIYpWjjjWg7+ruFVnoKQIM0GGvU/WV33vlXYU0el rn0ipnNNrOxjwHMc+ym9Xq9TYKv/0pVlSpicphtrVGi91T8149hJJ5S3K/Py8OPAOP9rMY fYlY2Pr37eIhUkg+xxPQxhoxWP7nPtT5HG56WLiFnCgLqDorSM8QGZBd+WqTnw== From: Claudius Heine Date: Thu, 20 Mar 2025 08:43:07 +0100 Subject: [PATCH v6 3/4] initramfs-crypt-hook: implement 'noencrypt' option MIME-Version: 1.0 Message-Id: <20250320-initramfs-crypt-hook-patches-2-v6-3-ef10c11cad94@denx.de> References: <20250320-initramfs-crypt-hook-patches-2-v6-0-ef10c11cad94@denx.de> In-Reply-To: <20250320-initramfs-crypt-hook-patches-2-v6-0-ef10c11cad94@denx.de> To: cip-dev@lists.cip-project.org Cc: Jan Kiszka , Quirin Gylstorff , Alexander , Claudius Heine X-Mailer: b4 0.14.2 X-Last-TLS-Session-Version: TLSv1.3 List-Id: X-Webhook-Received: from li982-79.members.linode.com [45.33.32.79] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Thu, 20 Mar 2025 07:43:26 -0000 X-Groupsio-URL: https://lists.cip-project.org/g/cip-dev/message/18286 In case encryption needs to be enabled via an update, while still allowing the update fall back to work. One update step where encryption is supported, but no reencryption is taking place if the device is not encrypted. For this the `noencrypt` hook is implemented, which requires some restructure/reordering of the `local-top-complete` script. Signed-off-by: Claudius Heine --- doc/README.tpm2.encryption.md | 22 +++++++++++++++++++- .../initramfs-crypt-hook/files/local-top-complete | 24 +++++++++++++++++----- 2 files changed, 40 insertions(+), 6 deletions(-) diff --git a/doc/README.tpm2.encryption.md b/doc/README.tpm2.encryption.md index 3f7e89f34fa4638a42285989e61370d8970afcde..2256f95a039044313807ab75ce219fa3eb7408b6 100644 --- a/doc/README.tpm2.encryption.md +++ b/doc/README.tpm2.encryption.md @@ -42,11 +42,12 @@ The initramfs-crypt-hook recipe has the following variables which can be overwri ### CRYPT_PARTITIONS The variable `CRYPT_PARTITIONS` contains the information which partition shall be encrypted where to mount it. -Each entry uses the schema `::`. +Each entry uses the schema `::`. - The `partition-idenitifer` is used to identify the partition on the disk, it can contain a partition label, partition UUID or absolute path to the partition device, e.g. `/dev/sda`. - The `mountpoint` is used mount the decrypted partition in the root file system - `reencrypt` uses `cryptsetup reencrypt` to encrypt the exiting content of the partition. This reduces the partition by 32MB and the file system by a similar amount - `format` creates a empty LUKS partition and creates a file system defined with the shell command given in `CRYPT_CREATE_FILE_SYSTEM_CMD` +- `noencrypt` will not try to encrypt the partition if it isn't encrypted already, but will open it if it is. See the section [Encrypting the shared partition via an update](#### Encrypting the shared partition via an update) for more information #### Encrypted root file system @@ -58,6 +59,25 @@ The mountpoint is empty as the root partition is mounted by a seperate initramf Both partitions are encrypted during first boot. The initramfs hook opens `${ABROOTFS_PART_UUID_A}` and `${ABROOTFS_PART_UUID_B}` during boot. +#### Encrypting the shared partition via an update + +With the following requirements, special handling is necessary: + +- A/B update scheme is used. +- Both slots have a shared volume that needs to be encrypted as well. +- The system in the field is currently unencrypted, and encryption should be added via an update. +- When the update fails, the fallback system needs to deal with an encrypted data partition. + +In this case, the fallback system needs to support an encrypted shared data partition but would not encrypt it on its own. For this, the `noencrypt` flag can be used. + +The data partition in the fallback system will have the `noencrypt` flag set, while the update system will set the flag to `reencrypt`. This will handle the following case: + +- Unencrypted system on slot A is running; the shared data partition has set the `noencrypt` flag and is not encrypted. +- Update for enabling encryption is applied to slot B, where the shared data partition has the `reencrypt` flag. +- System reboots to slot B, encrypting the shared data partition. +- Update fails at a later point and is not blessed; system reboots into the fallback system on slot A. +- Fallback system now needs to be able to use the shared data partition. + ### CRYPT_CREATE_FILE_SYSTEM_CMD The variable `CRYPT_CREATE_FILE_SYSTEM_CMD` contains the command to create a new file system on a newly diff --git a/recipes-initramfs/initramfs-crypt-hook/files/local-top-complete b/recipes-initramfs/initramfs-crypt-hook/files/local-top-complete index 6df4cccee9c99653fa9869ca2e46ead549d6fc2d..19df9ac9e22fde09dda8ea3ad76f7ff763d3cf1b 100644 --- a/recipes-initramfs/initramfs-crypt-hook/files/local-top-complete +++ b/recipes-initramfs/initramfs-crypt-hook/files/local-top-complete @@ -303,15 +303,18 @@ for partition_set in $partition_sets; do if [ ! -e "$part_device" ]; then panic "Could not find device mapped to '$partition' cannot be encrypted!" fi - decrypted_part=/dev/mapper/"$crypt_mount_name" - # check if we are trying to mount root - if [ "$partition_mountpoint" = "/" ]; then - echo "ROOT=$decrypted_part" >/conf/param.conf - fi + # If partition is already encrypted, decrypt and continue with next partition: + decrypted_part=/dev/mapper/"$crypt_mount_name" if /usr/sbin/cryptsetup luksDump --batch-mode "$part_device" \ | grep -q "systemd-tpm2\|clevis"; then open_tpm2_partition "$part_device" "$crypt_mount_name" "$tpm_device" + + # check if we are trying to mount root, set ROOT to decrypted partition: + if [ "$partition_mountpoint" = "/" ]; then + echo "ROOT=$decrypted_part" >/conf/param.conf + fi + continue fi @@ -321,6 +324,17 @@ for partition_set in $partition_sets; do partition_format="reencrypt" fi + # If partition should not be encrypted, continue with next partition: + if [ "$partition_format" = "noencrypt" ] + then + continue + fi + + # check if we are trying to mount root, set ROOT to decrypted partition: + if [ "$partition_mountpoint" = "/" ]; then + echo "ROOT=$decrypted_part" >/conf/param.conf + fi + # service watchdog in the background during lengthy re-encryption if [ -z "$watchdog_pid" ]; then service_watchdog &