OpenCloudOS-Kernel/include/uapi/linux/loadpin.h

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
 * Copyright (c) 2022, Google LLC
 */

#ifndef _UAPI_LINUX_LOOP_LOADPIN_H
#define _UAPI_LINUX_LOOP_LOADPIN_H

#define LOADPIN_IOC_MAGIC	'L'

/**
 * LOADPIN_IOC_SET_TRUSTED_VERITY_DIGESTS - Set up the root digests of verity devices
 *                                          that loadpin should trust.
 *
 * Takes a file descriptor from which to read the root digests of trusted verity devices. The file
 * is expected to contain a list of digests in ASCII format, with one line per digest. The ioctl
 * must be issued on the securityfs attribute 'loadpin/dm-verity' (which can be typically found
 * under /sys/kernel/security/loadpin/dm-verity).
 */
#define LOADPIN_IOC_SET_TRUSTED_VERITY_DIGESTS _IOW(LOADPIN_IOC_MAGIC, 0x00, unsigned int)

#endif /* _UAPI_LINUX_LOOP_LOADPIN_H */
LoadPin: Enable loading from trusted dm-verity devices Extend LoadPin to allow loading of kernel files from trusted dm-verity [1] devices. This change adds the concept of trusted verity devices to LoadPin. LoadPin maintains a list of root digests of verity devices it considers trusted. Userspace can populate this list through an ioctl on the new LoadPin securityfs entry 'dm-verity'. The ioctl receives a file descriptor of a file with verity digests as parameter. Verity reads the digests from this file after confirming that the file is located on the pinned root. The digest file must contain one digest per line. The list of trusted digests can only be set up once, which is typically done at boot time. When a kernel file is read LoadPin first checks (as usual) whether the file is located on the pinned root, if so the file can be loaded. Otherwise, if the verity extension is enabled, LoadPin determines whether the file is located on a verity backed device and whether the root digest of that device is in the list of trusted digests. The file can be loaded if the verity device has a trusted root digest. Background: As of now LoadPin restricts loading of kernel files to a single pinned filesystem, typically the rootfs. This works for many systems, however it can result in a bloated rootfs (and OTA updates) on platforms where multiple boards with different hardware configurations use the same rootfs image. Especially when 'optional' files are large it may be preferable to download/install them only when they are actually needed by a given board. Chrome OS uses Downloadable Content (DLC) [2] to deploy certain 'packages' at runtime. As an example a DLC package could contain firmware for a peripheral that is not present on all boards. DLCs use dm-verity to verify the integrity of the DLC content. [1] https://www.kernel.org/doc/html/latest/admin-guide/device-mapper/verity.html [2] https://chromium.googlesource.com/chromiumos/platform2/+/HEAD/dlcservice/docs/developer.md Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Acked-by: Mike Snitzer <snitzer@kernel.org> Link: https://lore.kernel.org/lkml/20220627083512.v7.2.I01c67af41d2f6525c6d023101671d7339a9bc8b5@changeid Signed-off-by: Kees Cook <keescook@chromium.org> 2022-06-27 23:35:25 +08:00			`/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */`
			`/*`
			`* Copyright (c) 2022, Google LLC`
			`*/`

			`#ifndef _UAPI_LINUX_LOOP_LOADPIN_H`
			`#define _UAPI_LINUX_LOOP_LOADPIN_H`

			`#define LOADPIN_IOC_MAGIC 'L'`

			`/**`
			`* LOADPIN_IOC_SET_TRUSTED_VERITY_DIGESTS - Set up the root digests of verity devices`
			`* that loadpin should trust.`
			`*`
			`* Takes a file descriptor from which to read the root digests of trusted verity devices. The file`
			`* is expected to contain a list of digests in ASCII format, with one line per digest. The ioctl`
			`* must be issued on the securityfs attribute 'loadpin/dm-verity' (which can be typically found`
			`* under /sys/kernel/security/loadpin/dm-verity).`
			`*/`
			`#define LOADPIN_IOC_SET_TRUSTED_VERITY_DIGESTS _IOW(LOADPIN_IOC_MAGIC, 0x00, unsigned int)`

			`#endif /* _UAPI_LINUX_LOOP_LOADPIN_H */`