legacy/intermediate_fw: Intermediate firmware for T1 (#1084)

* legacy/intermediate_fw: skeleton FW with RAM shim function

* legacy/intermediate_fw: reboot from RAM

* legacy/intermediate_fw: flash erase from RAM

* legacy/intermediate_fw: port flash erase body from cm3

* legacy/intermediate_fw: erase works with flash unlock

* legacy/intermediate_fw: wait for flash controller ready

* legacy/intermediate_fw: cleanup and add comments

* legacy/intermediate_fw: disable IRQ before reboot

* legacy/intermediate_fw: also erase storage

* legacy/intermediate_fw: style

* legacy/intermediate_fw: dialogs for update bootloader/erase FW

* legacy/intermediate_fw: style

* legacy/intermediate_fw: add bootloader replacement code

* legacy/intermediate_fw: add CI build script for intermediate FW

* legacy/intermediate_fw: call bootloader update

* legacy/intermediate_fw: add bootloader update dependency

* legacy/intermediate_fw: change setup() at start of main

* legacy/intermediate_fw: deduplicate code

* docs: table for MEMORY_PROTECT combinations that work on T1

* legacy/intermediate_fw: deduplicate code

* legacy/intermediate_fw: check if running in privileged mode

* legacy/intermediate_fw: style

* legacy/intermediate_fw: ChangeLog

* legacy/intermediate_fw: make version match latest bootloader included

* legacy/intermediate_fw: style

docs/legacy/index.md

@@ -105,3 +105,21 @@ Switch your device to bootloader mode, then execute:
 ```sh
 trezorctl firmware-update -f build/legacy/firmware/trezor.bin
 ```
+
+## Combining bootloader and firmware with various `MEMORY_PROTECT` settings, signed/unsigned
+
+Not all combinations of bootloader and firmware will work. This depends on
+3 variables: MEMORY_PROTECT of bootloader, MEMORY_PROTECT of firmware, whether firmware is signed
+
+This table shows the result for bootloader 1.8.0+ and 1.9.1+:
+
+| Bootloader MEMORY_PROTECT | Firmware MEMORY_PROTECT | Is firmware officially signed? | Result                                                                                     |
+| ------------------------- | ----------------------- | ------------------------------ | ------------------------------------------------------------------------------------------ |
+|  1                        |  1                      | yes                            | works, official configuration                                                              |
+|  1                        |  1                      | no                             | hardfault in header.S when setting VTOR and stack                                          |
+|  0                        |  1                      | no                             | works, but don't forget to comment out `check_bootloader`, otherwise it'll get overwritten |
+|  0                        |  0                      | no                             | hard fault because header.S doesn't set VTOR and stack right                               |
+|  1                        |  0                      | no                             | works                                                                                      |
+
+The other three possibilities with signed firmware and `MEMORY_PROTECT!=0` for bootloader/firmware don't exist.
+

legacy/firmware/bl_check.c

@@ -130,7 +130,13 @@ static int known_bootloader(int r, const uint8_t *hash) {
 }
 #endif
 
-void check_bootloader(void) {
+/**
+ * If bootloader is older and known, replace with newer bootloader.
+ * If bootloader is unknown, halt with error message.
+ *
+ * @param shutdown_on_success: if true, shuts down device instead of return
+ */
+void check_bootloader(bool shutdown_on_success) {
 #if MEMORY_PROTECT
   uint8_t hash[32] = {0};
   int r = memory_bootloader_hash(hash);
@@ -178,11 +184,13 @@ void check_bootloader(void) {
     // check whether the write was OK
     r = memory_bootloader_hash(hash);
     if (r == 32 && 0 == memcmp(hash, bl_hash, 32)) {
+      if (shutdown_on_success) {
         // OK -> show info and halt
         layoutDialog(&bmp_icon_info, NULL, NULL, NULL, _("Update finished"),
                      _("successfully."), NULL, _("Please reconnect"),
                      _("the device."), NULL);
         shutdown();
+      }
       return;
     }
   }
@@ -192,4 +200,6 @@ void check_bootloader(void) {
                _("contact our support."), NULL);
   shutdown();
 #endif
+  // prevent compiler warning when MEMORY_PROTECT==0
+  (void)shutdown_on_success;
 }

legacy/firmware/bl_check.h

@@ -20,6 +20,8 @@
 #ifndef __BL_CHECK_H__
 #define __BL_CHECK_H__
 
-void check_bootloader(void);
+#include <stdbool.h>
+
+void check_bootloader(bool shutdown_on_success);
 
 #endif

legacy/firmware/trezor.c

@@ -123,7 +123,7 @@ int main(void) {
                                    // unpredictable stack protection checks
   oledInit();
 #else
-  check_bootloader();
+  check_bootloader(true);
   setupApp();
   __stack_chk_guard = random32();  // this supports compiler provided
                                    // unpredictable stack protection checks

legacy/intermediate_fw/ChangeLog

@@ -0,0 +1,28 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
+
+## [Unreleased]
+
+### Added
+
+### Deprecated
+
+### Removed
+
+### Fixed
+
+### Security
+
+------------
+
+### Older changelog:
+
+Version 1.8.0 [Jun 2020]
+* Initial version of intermediate firmware
+* Updates bootloader to 1.8.0
+* Deletes storage and the intermediate firmware code
+* Version of intermediate firmware matches bootloader version included
+

legacy/intermediate_fw/Makefile

@@ -0,0 +1,60 @@
+APPVER = 1.8.0
+
+NAME  = trezor
+
+OBJS += trezor.o
+OBJS += header.o
+OBJS += bl_check.o
+OBJS += ../vendor/trezor-crypto/memzero.o
+OBJS += ../vendor/trezor-crypto/sha2.o
+
+OPTFLAGS ?= -Og
+
+
+../vendor/trezor-crypto/bip32.o: OPTFLAGS = -O3
+../vendor/trezor-crypto/bip39.o: OPTFLAGS = -O3
+../vendor/trezor-crypto/ecdsa.o: OPTFLAGS = -O3
+../vendor/trezor-crypto/sha2.o: OPTFLAGS = -O3
+../vendor/trezor-crypto/secp256k1.o: OPTFLAGS = -O3
+
+include ../Makefile.include
+CFLAGS:=$(filter-out -fstack-protector-all,$(CFLAGS))
+
+DEBUG_LINK ?= 0
+DEBUG_LOG  ?= 0
+
+CFLAGS += -Wno-sequence-point
+CFLAGS += -I../vendor/nanopb -Iprotob -DPB_FIELD_16BIT=1 -DPB_ENCODE_ARRAYS_UNPACKED=1 -DPB_VALIDATE_UTF8=1
+CFLAGS += -DDEBUG_LINK=$(DEBUG_LINK)
+CFLAGS += -DDEBUG_LOG=$(DEBUG_LOG)
+CFLAGS += -DSCM_REVISION='"$(shell git rev-parse HEAD | sed 's:\(..\):\\x\1:g')"'
+CFLAGS += -DUSE_MONERO=0
+ifneq ($(BITCOIN_ONLY),1)
+CFLAGS += -DUSE_ETHEREUM=1
+CFLAGS += -DUSE_NEM=1
+MAKO_RENDER_FLAG =
+else
+CFLAGS += -DUSE_ETHEREUM=0
+CFLAGS += -DUSE_NEM=0
+MAKO_RENDER_FLAG = --bitcoin-only
+endif
+
+%:: %.mako defs
+	@printf "  MAKO    $@\n"
+	$(Q)$(PYTHON) ../vendor/trezor-common/tools/cointool.py render $(MAKO_RENDER_FLAG) $@.mako
+
+bl_data.h: bl_data.py bootloader.dat
+	@printf "  PYTHON  bl_data.py\n"
+	$(Q)$(PYTHON) bl_data.py
+
+clean::
+	rm -f bl_data.h
+	find -maxdepth 1 -name "*.mako" | sed 's/.mako$$//' | xargs rm -f
+
+FIRMWARE_T1_START   = 0x08010000
+flash_intermediate_fw: trezor.bin
+	openocd -f interface/stlink-v2.cfg -c "transport select hla_swd" -f target/stm32f2x.cfg -c "init; reset halt; flash write_image erase $< $(FIRMWARE_T1_START); exit"
+
+openocd_reset:
+	$(OPENOCD) -c "init; reset; exit"
+

legacy/intermediate_fw/bl_check.c

@@ -0,0 +1 @@
+../firmware/bl_check.c

legacy/intermediate_fw/bl_check.h

@@ -0,0 +1 @@
+../firmware/bl_check.h

legacy/intermediate_fw/bl_data.py

@@ -0,0 +1 @@
+../firmware/bl_data.py

legacy/intermediate_fw/bootloader.dat

@@ -0,0 +1 @@
+../firmware/bootloader.dat

legacy/intermediate_fw/gettext.h

@@ -0,0 +1 @@
+../firmware/gettext.h

legacy/intermediate_fw/header.S

@@ -0,0 +1 @@
+../firmware/header.S

legacy/intermediate_fw/trezor.c

@@ -0,0 +1,125 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "trezor.h"
+#include <libopencm3/stm32/desig.h>
+#include <libopencm3/stm32/flash.h>
+#include <vendor/libopencm3/include/libopencmsis/core_cm3.h>
+#include "bitmaps.h"
+#include "bl_check.h"
+#include "layout.h"
+#include "memory.h"
+#include "memzero.h"
+#include "oled.h"
+#include "rng.h"
+#include "setup.h"
+#include "timer.h"
+#include "util.h"
+
+/** Sector erase operation extracted from libopencm3 - flash_erase_sector
+ * so it can run from RAM
+ */
+static void __attribute__((noinline, section(".data")))
+erase_sector(uint8_t sector, uint32_t psize) {
+  // Wait for flash controller to be ready
+  while ((FLASH_SR & FLASH_SR_BSY) == FLASH_SR_BSY)
+    ;
+  // Set program word width
+  FLASH_CR &= ~(FLASH_CR_PROGRAM_MASK << FLASH_CR_PROGRAM_SHIFT);
+  FLASH_CR |= psize << FLASH_CR_PROGRAM_SHIFT;
+
+  /* Sector numbering is not contiguous internally! */
+  if (sector >= 12) {
+    sector += 4;
+  }
+
+  FLASH_CR &= ~(FLASH_CR_SNB_MASK << FLASH_CR_SNB_SHIFT);
+  FLASH_CR |= (sector & FLASH_CR_SNB_MASK) << FLASH_CR_SNB_SHIFT;
+  FLASH_CR |= FLASH_CR_SER;
+  FLASH_CR |= FLASH_CR_STRT;
+
+  // Wait for flash controller to be ready
+  while ((FLASH_SR & FLASH_SR_BSY) == FLASH_SR_BSY)
+    ;
+  FLASH_CR &= ~FLASH_CR_SER;
+  FLASH_CR &= ~(FLASH_CR_SNB_MASK << FLASH_CR_SNB_SHIFT);
+}
+
+static void __attribute__((noinline, section(".data")))
+erase_firmware_and_storage(void) {
+  // Flash unlock
+  FLASH_KEYR = FLASH_KEYR_KEY1;
+  FLASH_KEYR = FLASH_KEYR_KEY2;
+
+  // Erase storage sectors to prevent firmware downgrade to vulnerable version
+  for (int i = FLASH_STORAGE_SECTOR_FIRST; i <= FLASH_STORAGE_SECTOR_LAST;
+       i++) {
+    erase_sector(i, FLASH_CR_PROGRAM_X32);
+  }
+
+  // Erase firmware sectors
+  for (int i = FLASH_CODE_SECTOR_FIRST; i <= FLASH_CODE_SECTOR_LAST; i++) {
+    erase_sector(i, FLASH_CR_PROGRAM_X32);
+  }
+
+  // Flash lock
+  FLASH_CR |= FLASH_CR_LOCK;
+}
+
+void __attribute__((noinline, noreturn, section(".data"))) reboot_device(void) {
+  __disable_irq();
+  SCB_AIRCR = SCB_AIRCR_VECTKEY | SCB_AIRCR_SYSRESETREQ;
+  while (1)
+    ;
+}
+
+/** Entry point of RAM shim that deletes old FW, storage and reboot */
+void __attribute__((noinline, noreturn, section(".data")))
+erase_fw_and_reboot(void) {
+  erase_firmware_and_storage();
+  reboot_device();
+
+  for (;;)
+    ;  // never reached, but compiler would generate error
+}
+
+int main(void) {
+  setupApp();
+  __stack_chk_guard = random32();  // this supports compiler provided
+                                   // unpredictable stack protection checks
+  oledInit();
+  if (is_mode_unprivileged()) {
+    layoutDialog(&bmp_icon_warning, NULL, NULL, NULL, "Cannot update", NULL,
+                 NULL, "Unprivileged mode", "Unsigned firmware", NULL);
+    shutdown();
+  }
+
+  mpu_config_off();  // needed for flash writable, RAM RWX
+  timer_init();
+  check_bootloader(false);
+
+  layoutDialog(&bmp_icon_warning, NULL, NULL, NULL, "Erasing old data", NULL,
+               NULL, "DO NOT UNPLUG", "YOUR TREZOR!", NULL);
+  oledRefresh();
+
+  // from this point the execution is from RAM instead of flash
+  erase_fw_and_reboot();
+
+  return 0;
+}

legacy/intermediate_fw/trezor.h

@@ -0,0 +1,40 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __TREZOR_H__
+#define __TREZOR_H__
+
+#include <stdint.h>
+#include "version.h"
+
+#define STR(X) #X
+#define VERSTR(X) STR(X)
+
+#ifndef DEBUG_LINK
+#define DEBUG_LINK 0
+#endif
+
+#ifndef DEBUG_LOG
+#define DEBUG_LOG 0
+#endif
+
+/* Screen timeout */
+extern uint32_t system_millis_lock_start;
+
+#endif

legacy/intermediate_fw/version.h

@@ -0,0 +1,8 @@
+// Matches the bootloader version included in this firmware
+#define VERSION_MAJOR 1
+#define VERSION_MINOR 8
+#define VERSION_PATCH 0
+
+#define FIX_VERSION_MAJOR 1
+#define FIX_VERSION_MINOR 8
+#define FIX_VERSION_PATCH 0

legacy/script/cibuild_intermediate_fw

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+# script/cibuild_intermediate_fw:
+#    Setup environment for CI to build intermediate firmware.
+
+set -e
+
+cd "$(dirname "$0")/.."
+
+make -C vendor/libopencm3 lib/stm32/f2
+
+make libtrezor.a
+
+make -C intermediate_fw all sign
+