firmware/stm32/sigheader.h
2026-03-04 17:32:21 -05:00

92 lines
3.8 KiB
C

// (c) Copyright 2018 by Coinkite Inc. This file is covered by license found in COPYING-CC.
//
#pragma once
#include <stdint.h>
// Our simple firmware header.
//
// Although called a header, this data is placed into the middle of the binary.
// It is located at start of firmware + 16k - sizeof(heaer). This is a gap unused in normal
// micropython layout. Exactly the last 64 bytes (signature) should be left out of
// the checksum. We do checksum areas beyond the end of the last byte of firmware (up to length)
// and expect those regions to be unprogrammed flash (ones).
//
// - timestamp must increase with each upgrade (downgrade protection)
// - version_string is for humans only
// - pubkey_num indicates which pubkey was used for signature
// - firmware_length, must be:
// - bigger than minimum length, less than max
// - 512-byte aligned
// - bootloader assumes the flash filesystem (FAT FS) follows the firmware.
// - this C header file is somewhat parsed and used by python signature-adding code
// - timestamp is YYMMDDHHMMSS0000 in BCD
//
typedef struct {
uint32_t magic_value; // fixed magic value
uint8_t timestamp[8]; // for downgrade protection, this must increase
uint8_t version_string[8]; // zero-terminated string: "1.0.0ab7" for humans
uint32_t pubkey_num; // which pubkey was used to sign binary
uint32_t firmware_length; // must be 512-aligned, and marks start of flash filesystem
uint32_t install_flags; // flags about this release
uint32_t hw_compat; // which hardware can run this release
uint8_t best_ts[8]; // for downgrade protection, recommended min timestamp
uint32_t future[5]; // reserved words
uint8_t signature[64]; // signature over secp256k1
} coldcardFirmwareHeader_t;
#define FW_HEADER_SIZE 128
#define FW_HEADER_OFFSET (0x4000-FW_HEADER_SIZE)
#define FW_HEADER_MAGIC 0xCC001234
// Firmware Image Size
// arbitrary min size
#define FW_MIN_LENGTH (256*1024)
// (mk1-3) absolute max size: 1MB flash - 32k for bootloader = 1,015,808
// - but practical limit for our-protocol USB upgrades: 786432 (or else settings damaged)
#define FW_MAX_LENGTH (0x100000 - 0x8000)
// .. for Mk4: 2Mbytes, less bootrom of 128k.
#define FW_MAX_LENGTH_MK4 (0x200000 - 0x20000)
// Arguments to be used w/ python's struct module.
#define FWH_PY_FORMAT "<I8s8sIIII8s20s64s"
#define FWH_PY_VALUES "magic_value timestamp version_string pubkey_num firmware_length install_flags hw_compat best_ts future signature"
#define FWH_NUM_FUTURE 7
// offset of pubkey number
#define FWH_PK_NUM_OFFSET 20
// Bits in install_flags
#define FWHIF_HIGH_WATER 0x01
#define FWHIF_BEST_TS 0x02
// Bits in hw_compat
#define MK_1_OK 0x01
#define MK_2_OK 0x02
#define MK_3_OK 0x04
#define MK_4_OK 0x08
#define MK_Q1_OK 0x10
#define MK_5_OK 0x20
// (Mk1-3) There is a copy of the header at this location in RAM, copied by bootloader
// **after** it has been verified. If you write to this memory area, you will be reset!
// .. in mk4, no header copy anymore
#define RAM_HEADER_BASE 0x10007c20
// Original copy of header, as recorded in flash/firmware file.
#define FLASH_HEADER_BASE 0x0800bf80
#define FLASH_HEADER_BASE_MK4 0x08023f80
// (Mk1-3) One 32-bit word of flags from bootloader about how we got here (in protected RAM)
#define RAM_BOOT_FLAGS (RAM_HEADER_BASE + FW_HEADER_SIZE)
// Bitmask for RAM_BOOT_FLAGS
// - we just did a firmware upgrade on this bootup
#define RBF_FRESH_VERSION 0x01
// - factory mode: flash not yet locked-down
#define RBF_FACTORY_MODE 0x02