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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Structures used by the ChromiumOS bootmeth
*
* See docs at:
* https://www.chromium.org/chromium-os/chromiumos-design-docs/verified-boot-data-structures/
*
* Original code at:
* https://chromium.googlesource.com/chromiumos/platform/vboot_reference/+/refs/heads/main/firmware/2lib/include/2struct.h
*
* Code taken from vboot_reference commit 5b8596ce file 2struct.h
*
* Copyright 2023 Google LLC
* Written by Simon Glass <sjg@chromium.org>
*/
#ifndef __BOOTMETH_CROS_H
#define __BOOTMETH_CROS_H
/* Signature data (a secure hash, possibly signed) */
struct vb2_signature {
/* Offset of signature data from start of this struct */
uint32_t sig_offset;
uint32_t reserved0;
/* Size of signature data in bytes */
uint32_t sig_size;
uint32_t reserved1;
/* Size of the data block which was signed in bytes */
uint32_t data_size;
uint32_t reserved2;
} __attribute__((packed));
#define EXPECTED_VB2_SIGNATURE_SIZE 24
/* Packed public key data */
struct vb2_packed_key {
/* Offset of key data from start of this struct */
uint32_t key_offset;
uint32_t reserved0;
/* Size of key data in bytes (NOT strength of key in bits) */
uint32_t key_size;
uint32_t reserved1;
/* Signature algorithm used by the key (enum vb2_crypto_algorithm) */
uint32_t algorithm;
uint32_t reserved2;
/* Key version */
uint32_t key_version;
uint32_t reserved3;
/* TODO: when redoing this struct, add a text description of the key */
} __attribute__((packed));
#define EXPECTED_VB2_PACKED_KEY_SIZE 32
#define VB2_KEYBLOCK_MAGIC "CHROMEOS"
#define VB2_KEYBLOCK_MAGIC_SIZE 8
/*
* Keyblock, containing the public key used to sign some other chunk of data.
*
* This should be followed by:
* 1) The data_key key data, pointed to by data_key.key_offset.
* 2) The checksum data for (vb2_keyblock + data_key data), pointed to
* by keyblock_checksum.sig_offset.
* 3) The signature data for (vb2_keyblock + data_key data), pointed to
* by keyblock_signature.sig_offset.
*/
struct vb2_keyblock {
/* Magic number */
uint8_t magic[VB2_KEYBLOCK_MAGIC_SIZE];
/* Version of this header format */
uint32_t header_version_major;
uint32_t header_version_minor;
/*
* Length of this entire keyblock, including keys, signatures, and
* padding, in bytes
*/
uint32_t keyblock_size;
uint32_t reserved0;
/*
* Signature for this keyblock (header + data pointed to by data_key)
* For use with signed data keys
*/
struct vb2_signature keyblock_signature;
/*
* SHA-512 hash for this keyblock (header + data pointed to by
* data_key) For use with unsigned data keys.
*
* Only supported for kernel keyblocks, not firmware keyblocks.
*/
struct vb2_signature keyblock_hash;
/* Flags for key (VB2_KEYBLOCK_FLAG_*) */
uint32_t keyblock_flags;
uint32_t reserved1;
/* Key to verify the chunk of data */
struct vb2_packed_key data_key;
} __attribute__((packed));
#define EXPECTED_VB2_KEYBLOCK_SIZE 112
/*
* Preamble block for kernel, version 2.2
*
* This should be followed by:
* 1) The signature data for the kernel body, pointed to by
* body_signature.sig_offset.
* 2) The signature data for (vb2_kernel_preamble + body signature data),
* pointed to by preamble_signature.sig_offset.
* 3) The 16-bit vmlinuz header, which is used for reconstruction of
* vmlinuz image.
*/
struct vb2_kernel_preamble {
/*
* Size of this preamble, including keys, signatures, vmlinuz header,
* and padding, in bytes
*/
uint32_t preamble_size;
uint32_t reserved0;
/* Signature for this preamble (header + body signature) */
struct vb2_signature preamble_signature;
/* Version of this header format */
uint32_t header_version_major;
uint32_t header_version_minor;
/* Kernel version */
uint32_t kernel_version;
uint32_t reserved1;
/* Load address for kernel body */
uint64_t body_load_address;
/* TODO (vboot 2.1): we never used that */
/* Address of bootloader, after body is loaded at body_load_address */
uint64_t bootloader_address;
/* TODO (vboot 2.1): should be a 32-bit offset */
/* Size of bootloader in bytes */
uint32_t bootloader_size;
uint32_t reserved2;
/* Signature for the kernel body */
struct vb2_signature body_signature;
/*
* TODO (vboot 2.1): fields for kernel offset and size. Right now the
* size is implicitly the same as the size of data signed by the body
* signature, and the offset is implicitly at the end of the preamble.
* But that forces us to pad the preamble to 64KB rather than just
* having a tiny preamble and an offset field.
*/
/*
* Fields added in header version 2.1. You must verify the header
* version before reading these fields!
*/
/*
* Address of 16-bit header for vmlinuz reassembly. Readers should
* return 0 for header version < 2.1.
*/
uint64_t vmlinuz_header_address;
/* Size of 16-bit header for vmlinuz in bytes. Readers should return 0
for header version < 2.1 */
uint32_t vmlinuz_header_size;
uint32_t reserved3;
/*
* Fields added in header version 2.2. You must verify the header
* version before reading these fields!
*/
/*
* Flags; see VB2_KERNEL_PREAMBLE_*. Readers should return 0 for
* header version < 2.2. Flags field is currently defined as:
* [31:2] - Reserved (for future use)
* [1:0] - Kernel image type (0b00 - CrOS,
* 0b01 - bootimg,
* 0b10 - multiboot)
*/
uint32_t flags;
} __attribute__((packed));
#endif /* __BOOTMETH_CROS_H */
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