firmware/stm32/bootloader/pins.h
2020-11-18 14:19:14 -05:00

119 lines
5.3 KiB
C

/*
* (c) Copyright 2018 by Coinkite Inc. This file is covered by license found in COPYING-CC.
*
* pins.h -- everything to do with PIN's and their policies
*
*/
#pragma once
#include "basics.h"
#include "ae.h"
// We hash it like we don't care, but PIN code is expected to be
// just digits, no punctuation, and up to this many chars long.
// Using pin+len rather than c-strings. Use zero-length for "blank" or "undefined" pins.
//
#define MAX_PIN_LEN 32
// Number of bytes (per pin) we are keeping secret.
// ATECC[56]08A limitation/feature caps this at weird 72 byte value.
#define AE_SECRET_LEN 72
// .. but on 608a, we can use this one weird data slot with more space
#define AE_LONG_SECRET_LEN 416
// For change_flags field: choose one secret and/or one PIN only.
#define CHANGE_WALLET_PIN 0x001
#define CHANGE_DURESS_PIN 0x002
#define CHANGE_BRICKME_PIN 0x004
#define CHANGE_SECRET 0x008
#define CHANGE_DURESS_SECRET 0x010
#define CHANGE_SECONDARY_WALLET_PIN 0x020 // when used from main wallet only (obsolete)
#define CHANGE_LS_OFFSET 0xf00 // v2: which 32-byte part of long-secret to affect
#define CHANGE__MASK 0xf3f
// Magic value and/or version number.
#define PA_MAGIC_V1 0x2eaf6311 // before v3.0.0 of main firmware (508a, mk1/2)
#define PA_MAGIC_V2 0x2eaf6312
// For state_flags field: report only covers current wallet (primary vs. secondary)
#define PA_SUCCESSFUL 0x01
#define PA_IS_BLANK 0x02
#define PA_HAS_DURESS 0x04
#define PA_HAS_BRICKME 0x08
#define PA_ZERO_SECRET 0x10
typedef struct {
uint32_t magic_value; // = PA_MAGIC
int is_secondary; // (bool) primary or secondary [obsolete]
char pin[MAX_PIN_LEN]; // value being attempted
int pin_len; // valid length of pin
uint32_t delay_achieved; // so far, how much time wasted? [obsolete]
uint32_t delay_required; // how much will be needed? [obsolete]
uint32_t num_fails; // for UI: number of fails PINs
uint32_t attempts_left; // trys left until bricking
uint32_t state_flags; // what things have been setup/enabled already
uint32_t private_state; // some internal (encrypted) state [actually a nonce]
uint8_t hmac[32]; // my hmac over above, or zeros
// remaining fields are return values, or optional args;
int change_flags; // bitmask of what to do
char old_pin[MAX_PIN_LEN]; // (optional) old PIN value
int old_pin_len; // (optional) valid length of old_pin, can be zero
char new_pin[MAX_PIN_LEN]; // (optional) new PIN value
int new_pin_len; // (optional) valid length of new_pin, can be zero
uint8_t secret[AE_SECRET_LEN]; // secret to be changed / return value
// may grow from here in future versions.
uint8_t cached_main_pin[32]; // iff they provided right pin already
} pinAttempt_t;
// For binary compatibility with Mark1/2 bootroms, the cached_main_pin is optional
#define PIN_ATTEMPT_SIZE_V1 (176+AE_SECRET_LEN)
#define PIN_ATTEMPT_SIZE_V2 (176+AE_SECRET_LEN+32)
// Errors codes
enum {
EPIN_HMAC_FAIL = -100,
EPIN_HMAC_REQUIRED = -101,
EPIN_BAD_MAGIC = -102,
EPIN_RANGE_ERR = -103,
EPIN_BAD_REQUEST = -104, // bad change flags
EPIN_I_AM_BRICK = -105, // chip has been bricked
EPIN_AE_FAIL = -106, // low-level fails; retry ok
EPIN_MUST_WAIT = -107, // you haven't waited long enough
EPIN_PIN_REQUIRED = -108, // must be non-zero length
EPIN_WRONG_SUCCESS = -109, // success field is not what is needs to be
EPIN_OLD_ATTEMPT = -110, // tried to recycle older attempt
EPIN_AUTH_MISMATCH = -111, // need pin1 to change duress1, etc.
EPIN_AUTH_FAIL = -112, // pin is wrong
EPIN_OLD_AUTH_FAIL = -113, // existing pin is wrong (during change attempt)
EPIN_PRIMARY_ONLY = -114, // only primary pin can change brickme
};
// Get number of failed attempts on a PIN, since last success. Calculate
// required delay, and setup initial struct for later attempts. Does not
// attempt the PIN or return secrets if right.
int pin_setup_attempt(pinAttempt_t *args);
// Delay for one time unit, and prove it. Doesn't check PIN value itself.
int pin_delay(pinAttempt_t *args);
// Do the PIN check, and return a value. Or fail.
int pin_login_attempt(pinAttempt_t *args);
// Change the PIN and/or secrets (must also know the value, or it must be blank)
int pin_change(pinAttempt_t *args);
// To encourage not keeping the secret in memory, a way to fetch it after already prove you
// know the PIN right.
int pin_fetch_secret(pinAttempt_t *args);
// Record current flash checksum and make green light go on.
int pin_firmware_greenlight(pinAttempt_t *args);
// Return 32 bits of bits which are presistently mapped from pin code; for anti-phishing feature.
int pin_prefix_words(const char *pin_prefix, int prefix_len, uint32_t *result);
// Read/write the long secret. 32 bytes at a time.
int pin_long_secret(pinAttempt_t *args);
// EOF