trezor-firmware/core/embed/trezorhal/common.c

/*
 * This file is part of the Trezor project, https://trezor.io/
 *
 * Copyright (c) SatoshiLabs
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include STM32_HAL_H

#include <string.h>

#include "common.h"
#include "display.h"
#include "flash.h"
#include "hmac_drbg.h"
#include "rand.h"

#include "stm32f4xx_ll_utils.h"

// from util.s
extern void shutdown(void);

static HMAC_DRBG_CTX drbg_ctx;

#define COLOR_FATAL_ERROR RGB16(0x7F, 0x00, 0x00)

void __attribute__((noreturn))
__fatal_error(const char *expr, const char *msg, const char *file, int line,
              const char *func) {
  display_orientation(0);
  display_backlight(255);
  display_print_color(COLOR_WHITE, COLOR_FATAL_ERROR);
  display_printf("\nFATAL ERROR:\n");
  if (expr) {
    display_printf("expr: %s\n", expr);
  }
  if (msg) {
    display_printf("msg : %s\n", msg);
  }
  if (file) {
    display_printf("file: %s:%d\n", file, line);
  }
  if (func) {
    display_printf("func: %s\n", func);
  }
#ifdef GITREV
  display_printf("rev : %s\n", XSTR(GITREV));
#endif
  display_printf("\nPlease contact Trezor support.\n");
  shutdown();
  for (;;)
    ;
}

void __attribute__((noreturn))
error_shutdown(const char *line1, const char *line2, const char *line3,
               const char *line4) {
  display_orientation(0);
#ifdef TREZOR_FONT_NORMAL_ENABLE
  display_clear();
  display_bar(0, 0, DISPLAY_RESX, DISPLAY_RESY, COLOR_FATAL_ERROR);
  int y = 32;
  if (line1) {
    display_text(8, y, line1, -1, FONT_NORMAL, COLOR_WHITE, COLOR_FATAL_ERROR);
    y += 32;
  }
  if (line2) {
    display_text(8, y, line2, -1, FONT_NORMAL, COLOR_WHITE, COLOR_FATAL_ERROR);
    y += 32;
  }
  if (line3) {
    display_text(8, y, line3, -1, FONT_NORMAL, COLOR_WHITE, COLOR_FATAL_ERROR);
    y += 32;
  }
  if (line4) {
    display_text(8, y, line4, -1, FONT_NORMAL, COLOR_WHITE, COLOR_FATAL_ERROR);
    y += 32;
  }
  y += 32;
  display_text(8, y, "Please unplug the device.", -1, FONT_NORMAL, COLOR_WHITE,
               COLOR_FATAL_ERROR);
#else
  display_print_color(COLOR_WHITE, COLOR_FATAL_ERROR);
  if (line1) {
    display_printf("%s\n", line1);
  }
  if (line2) {
    display_printf("%s\n", line2);
  }
  if (line3) {
    display_printf("%s\n", line3);
  }
  if (line4) {
    display_printf("%s\n", line4);
  }
  display_printf("\nPlease unplug the device.\n");
#endif
  display_backlight(255);
  shutdown();
  for (;;)
    ;
}

#ifndef NDEBUG
void __assert_func(const char *file, int line, const char *func,
                   const char *expr) {
  __fatal_error(expr, "assert failed", file, line, func);
}
#endif

void hal_delay(uint32_t ms) { HAL_Delay(ms); }

/*
 * Generates a delay of random length. Use this to protect sensitive code
 * against fault injection.
 */
void wait_random(void) {
  int wait = drbg_random32() & 0xff;
  volatile int i = 0;
  volatile int j = wait;
  while (i < wait) {
    if (i + j != wait) {
      shutdown();
    }
    ++i;
    --j;
  }
  // Double-check loop completion.
  if (i != wait || j != 0) {
    shutdown();
  }
}

// reference RM0090 section 35.12.1 Figure 413
#define USB_OTG_HS_DATA_FIFO_RAM (USB_OTG_HS_PERIPH_BASE + 0x20000U)
#define USB_OTG_HS_DATA_FIFO_SIZE (4096U)

void clear_otg_hs_memory(void) {
  // use the HAL version due to section 2.1.6 of STM32F42xx Errata sheet
  __HAL_RCC_USB_OTG_HS_CLK_ENABLE();  // enable USB_OTG_HS peripheral clock so
                                      // that the peripheral memory is
                                      // accessible
  memset_reg(
      (volatile void *)USB_OTG_HS_DATA_FIFO_RAM,
      (volatile void *)(USB_OTG_HS_DATA_FIFO_RAM + USB_OTG_HS_DATA_FIFO_SIZE),
      0);
  __HAL_RCC_USB_OTG_HS_CLK_DISABLE();  // disable USB OTG_HS peripheral clock as
                                       // the peripheral is not needed right now
}

uint32_t __stack_chk_guard = 0;

void __attribute__((noreturn)) __stack_chk_fail(void) {
  ensure(secfalse, "Stack smashing detected");
}

uint8_t HW_ENTROPY_DATA[HW_ENTROPY_LEN];

void collect_hw_entropy(void) {
  // collect entropy from UUID
  uint32_t w = LL_GetUID_Word0();
  memcpy(HW_ENTROPY_DATA, &w, 4);
  w = LL_GetUID_Word1();
  memcpy(HW_ENTROPY_DATA + 4, &w, 4);
  w = LL_GetUID_Word2();
  memcpy(HW_ENTROPY_DATA + 8, &w, 4);

  // set entropy in the OTP randomness block
  if (secfalse == flash_otp_is_locked(FLASH_OTP_BLOCK_RANDOMNESS)) {
    uint8_t entropy[FLASH_OTP_BLOCK_SIZE];
    random_buffer(entropy, FLASH_OTP_BLOCK_SIZE);
    ensure(flash_otp_write(FLASH_OTP_BLOCK_RANDOMNESS, 0, entropy,
                           FLASH_OTP_BLOCK_SIZE),
           NULL);
    ensure(flash_otp_lock(FLASH_OTP_BLOCK_RANDOMNESS), NULL);
  }
  // collect entropy from OTP randomness block
  ensure(flash_otp_read(FLASH_OTP_BLOCK_RANDOMNESS, 0, HW_ENTROPY_DATA + 12,
                        FLASH_OTP_BLOCK_SIZE),
         NULL);
}

void drbg_init(void) {
  uint8_t entropy[48];
  random_buffer(entropy, sizeof(entropy));
  hmac_drbg_init(&drbg_ctx, entropy, sizeof(entropy), NULL, 0);
}

void drbg_reseed(const uint8_t *entropy, size_t len) {
  hmac_drbg_reseed(&drbg_ctx, entropy, len, NULL, 0);
}

void drbg_generate(uint8_t *buf, size_t len) {
  hmac_drbg_generate(&drbg_ctx, buf, len);
}

uint32_t drbg_random32(void) {
  uint32_t value;
  drbg_generate((uint8_t *)&value, sizeof(value));
  return value;
}