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Diffstat (limited to 'boot/bootmeth_cros.h')
| -rw-r--r-- | boot/bootmeth_cros.h | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/boot/bootmeth_cros.h b/boot/bootmeth_cros.h new file mode 100644 index 0000000..8e30385 --- /dev/null +++ b/boot/bootmeth_cros.h @@ -0,0 +1,197 @@ +/* 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 */ |