From patchwork Wed Mar 5 12:00:22 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudius Heine X-Patchwork-Id: 14002516 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 0EA87C28B21 for ; Wed, 5 Mar 2025 12:00:33 +0000 (UTC) Received: from mx.denx.de (mx.denx.de [89.58.32.78]) by mx.groups.io with SMTP id smtpd.web11.11518.1741176030915002824 for ; Wed, 05 Mar 2025 04:00:31 -0800 Authentication-Results: mx.groups.io; dkim=pass header.i=@denx.de header.s=mx-20241105 header.b=Gky8XVAb; 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 DF65410381917; Wed, 5 Mar 2025 13:00:28 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=mx-20241105; t=1741176029; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=Ar9i5uoYNTSZOR9/ngQUlwwzjxUUGvbjeGVrXQYBa8A=; b=Gky8XVAbVuWQ6Qf7hF+gvAirtyPfqN22GszPrjPHFeya+bV8pE3YOmo4mgn/83bjCXRlWe XHO1EWCmkxIcUo6mfu1cauttHi5lIK3vHRwp21Fuv6su4OrGonUFvMNF3uJFZLd5y+6ZPo JIIaI9eNRint3gV1g8y/Y3y/bBaNBIxCyPIQh27ZfMSNvtOeOjgzG4k640gHsWMgqHmCBX UYDvNZZNI0Wz7RN5SwWe2JclQmZaA2rwc1OcvSGJUrmpdPgDGuCkt+xmwwYxU8cuGhcQDb XAcp5q7fBe/Ojb+Wdfwi/FrXDhno1t2hoKluju1hqML8dGFk1fgRgcuXB7NYnQ== From: Claudius Heine Date: Wed, 05 Mar 2025 13:00:22 +0100 Subject: [PATCH v4 4/5] initramfs-crypt-hook: implement 'noencrypt' option MIME-Version: 1.0 Message-Id: <20250305-initramfs-crypt-hook-patches-2-v4-4-4170912e5261@denx.de> References: <20250305-initramfs-crypt-hook-patches-2-v4-0-4170912e5261@denx.de> In-Reply-To: <20250305-initramfs-crypt-hook-patches-2-v4-0-4170912e5261@denx.de> To: cip-dev@lists.cip-project.org Cc: Jan Kiszka , Quirin Gylstorff , 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 ; Wed, 05 Mar 2025 12:00:33 -0000 X-Groupsio-URL: https://lists.cip-project.org/g/cip-dev/message/18045 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 2660812b1689703336f1dbf3c07b7bbfb9f9b0f3..e0b5372da92148fc8b2df86b7e4b491daf740c30 100644 --- a/recipes-initramfs/initramfs-crypt-hook/files/local-top-complete +++ b/recipes-initramfs/initramfs-crypt-hook/files/local-top-complete @@ -255,15 +255,18 @@ 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 @@ -273,6 +276,17 @@ 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 &