wolfBoot can update itself when compiled with RAM_CODE=1

- Added wolfBoot version
- Added extra 16bit header tag to identify the image type and authentication
- Implemented optional in-ram self-update of the bootloader, with version control
and authentication mechanism (not fail-safe)

Author: danielinux

Makefile

@@ -21,14 +21,15 @@ EXT_FLASH?=0
 SPI_FLASH?=0
 ALLOW_DOWNGRADE?=0
 NVM_FLASH_WRITEONCE?=0
+WOLFBOOT_VERSION?=0
 V?=0
 SPMATH?=1
 RAM_CODE?=0
 
 
 
 ## Initializers
-CFLAGS:=-D__WOLFBOOT 
+CFLAGS:=-D__WOLFBOOT  -DWOLFBOOT_VERSION=$(WOLFBOOT_VERSION)UL
 LSCRIPT:=hal/$(TARGET).ld
 LDFLAGS:=-T $(LSCRIPT) -Wl,-gc-sections -Wl,-Map=wolfboot.map -ffreestanding -nostartfiles 
 OBJS:= \
@@ -147,7 +148,8 @@ wolfboot-align.bin: wolfboot.bin
 	@echo
 
 test-app/image.bin:
-	@make -C test-app TARGET=$(TARGET) EXT_FLASH=$(EXT_FLASH) SPI_FLASH=$(SPI_FLASH) ARCH=$(ARCH) V=$(V) \
+	@make -C test-app TARGET=$(TARGET) EXT_FLASH=$(EXT_FLASH) SPI_FLASH=$(SPI_FLASH) ARCH=$(ARCH) \
+    V=$(V) RAM_CODE=$(RAM_CODE) WOLFBOOT_VERSION=$(WOLFBOOT_VERSION)\
 	KINETIS=$(KINETIS) KINETIS_CPU=$(KINETIS_CPU) KINETIS_DRIVERS=$(KINETIS_DRIVERS) \
 	KINETIS_CMSIS=$(KINETIS_CMSIS) NVM_FLASH_WRITEONCE=$(NVM_FLASH_WRITEONCE) \
 	FREEDOM_E_SDK=$(FREEDOM_E_SDK)

hal/hifive1.ld

@@ -19,6 +19,7 @@ SECTIONS
         KEEP(*(.isr_vector))
         *(.text*)
         *(.rodata*)
+        *(.srodata*)
         . = ALIGN(4);
         _end_text = .;
     } > FLASH

include/hal.h

@@ -4,6 +4,13 @@
 
 #include <inttypes.h>
 #include "target.h"
+
+/* Architecture specific calls */
+extern void do_boot(const uint32_t *app_offset);
+extern void arch_reboot(void);
+
+
+
 void hal_init(void);
 int hal_flash_write(uint32_t address, const uint8_t *data, int len);
 int hal_flash_erase(uint32_t address, int len);

include/image.h

@@ -41,6 +41,9 @@ int wolfBoot_set_sector_flag(uint8_t part, uint8_t sector, uint8_t newflag);
 int wolfBoot_get_partition_state(uint8_t part, uint8_t *st);
 int wolfBoot_get_sector_flag(uint8_t part, uint8_t sector, uint8_t *flag);
 
+/* Defined in libwolfboot */
+uint8_t wolfBoot_find_header(uint8_t *haystack, uint8_t type, uint8_t **ptr);
+
 #ifdef EXT_FLASH
 # ifdef PART_UPDATE_EXT
 #  define UPDATE_EXT 1

include/wolfboot/wolfboot.h

@@ -13,10 +13,27 @@
 #define HDR_VERSION     0x01
 #define HDR_TIMESTAMP   0x02
 #define HDR_SHA256      0x03
+#define HDR_IMG_TYPE    0x04
 #define HDR_PUBKEY      0x10
 #define HDR_SIGNATURE   0x20
 #define HDR_PADDING     0xFF
 
+#define HDR_IMG_TYPE_AUTH_ED25519 0x0100
+#define HDR_IMG_TYPE_AUTH_ECC256  0x0200
+#define HDR_IMG_TYPE_WOLFBOOT     0x0000
+#define HDR_IMG_TYPE_APP          0x0001
+
+
+#ifdef __WOLFBOOT
+ #if defined(WOLFBOOT_SIGN_ED25519)
+ #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_ED25519
+ #elif defined(WOLFBOOT_SIGN_ECC256)
+ #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_ECC256
+ #else
+ #   error "no valid authentication mechanism selected. Please define WOLFBOOT_SIGN_ED25519 or WOLFBOOT_SIGN_ECC256"
+ #endif /* defined WOLFBOOT_SIGN_ECC256 || WOLFBOOT_SIGN_ED25519 */
+#endif /* defined WOLFBOOT */
+
 #define PART_BOOT   0
 #define PART_UPDATE 1
 #define PART_SWAP   2
@@ -26,6 +43,8 @@
 #define IMG_STATE_TESTING 0x10
 #define IMG_STATE_SUCCESS 0x00
 
+
+
 void wolfBoot_erase_partition(uint8_t part);
 void wolfBoot_update_trigger(void);
 void wolfBoot_success(void);

src/boot_arm.c

@@ -1,4 +1,4 @@
-/* boot_arm.c 
+/* boot_arm.c
  *
  * Copyright (C) 2018 wolfSSL Inc.
  *
@@ -18,9 +18,10 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
  */
-#include <loader.h>
+#include "image.h"
+#include "loader.h"
 #include <stdint.h>
-#include <wolfboot/wolfboot.h>
+#include "wolfboot/wolfboot.h"
 extern unsigned int _stored_data;
 extern unsigned int _start_data;
 extern unsigned int _end_data;
@@ -33,7 +34,7 @@ extern void main(void);
 
 void isr_reset(void) {
     register unsigned int *src, *dst;
-#ifdef PLATFORM_kinetis 
+#ifdef PLATFORM_kinetis
     /* Immediately disable Watchdog after boot */
     /*  Write Keys to unlock register */
     *((volatile unsigned short *)0x4005200E) = 0xC520;
@@ -86,6 +87,7 @@ void isr_empty(void)
 static void  *app_entry;
 static uint32_t app_end_stack;
 
+
 void do_boot(const uint32_t *app_offset)
 {
 
@@ -171,3 +173,18 @@ void (* const IV[])(void) =
     isr_empty,
     isr_empty,
 };
+
+#ifdef RAM_CODE
+
+#define AIRCR *(volatile uint32_t *)(0xE000ED0C)
+#define AIRCR_VKEY (0x05FA << 16)
+#   define AIRCR_SYSRESETREQ (1 << 2)
+
+void RAMFUNCTION arch_reboot(void)
+{
+    AIRCR = AIRCR_SYSRESETREQ | AIRCR_VKEY;
+    while(1)
+        ;
+
+}
+#endif

src/boot_riscv.c

@@ -20,6 +20,7 @@
  */
 
 #include <stdint.h>
+#include "image.h"
 
 extern void trap_entry(void);
 extern void trap_exit(void);
@@ -36,6 +37,12 @@ extern uint32_t  _global_pointer;
 extern void (* const IV[])(void);
 
 extern void main(void);
+void RAMFUNCTION reloc_iv(uint32_t *address)
+{
+    asm volatile("csrw mtvec, %0":: "r"(address + 1));
+}
+
+
 void __attribute__((naked,section(".init"))) _reset(void) {
     register uint32_t *src, *dst;
     asm volatile("la gp, _global_pointer");
@@ -83,4 +90,31 @@ void isr_empty(void)
 
 }
 
+#ifdef RAM_CODE
+
+#define AON_WDOGCFG  *(volatile uint32_t *)(0x10000000UL)
+#define AON_WDOGKEY  *(volatile uint32_t *)(0x1000001CUL)
+#define AON_WDOGFEED *(volatile uint32_t *)(0x10000018UL)
+#define AON_WDOGCMP  *(volatile uint32_t *)(0x10000020UL)
+
+#define AON_WDOGKEY_VALUE       0x0051F15E
+#define AON_WDOGCFG_SCALE       0x0000000F
+#define AON_WDOGCFG_RSTEN       0x00000100
+#define AON_WDOGCFG_ZEROCMP     0x00000200
+#define AON_WDOGCFG_ENALWAYS    0x00001000
+
+
+void RAMFUNCTION arch_reboot(void)
+{
+    AON_WDOGKEY = AON_WDOGKEY_VALUE;
+    AON_WDOGCMP = 0;
+    //wdogconfig: : wdogrsten | enablealways | reset to 0 | max scale
+    AON_WDOGKEY = AON_WDOGKEY_VALUE;
+    AON_WDOGCFG |= (AON_WDOGCFG_RSTEN | AON_WDOGCFG_ENALWAYS | AON_WDOGCFG_ZEROCMP | AON_WDOGCFG_SCALE) ;
+    AON_WDOGKEY = AON_WDOGKEY_VALUE;
+    AON_WDOGFEED = 1;
+    while(1)
+        ;
+}
+#endif
 

src/image.c

@@ -18,18 +18,16 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
  */
-#include <image.h>
-#include <hal.h>
+#include "loader.h"
+#include "image.h"
+#include "hal.h"
 #include <wolfssl/wolfcrypt/sha256.h>
 #include <wolfssl/ssl.h>
-#include <loader.h>
 
 #ifdef WOLFBOOT_SIGN_ED25519
 #include <wolfssl/wolfcrypt/ed25519.h>
 
 
-extern uint8_t wolfBoot_find_header(uint8_t *haystack, uint8_t type, uint8_t **ptr);
-
 static int wolfBoot_verify_signature(uint8_t *hash, uint8_t *sig)
 {
     int ret, res;
@@ -266,6 +264,9 @@ int wolfBoot_verify_authenticity(struct wolfBoot_image *img)
     uint8_t stored_signature_size;
     uint8_t *pubkey_hint;
     uint8_t pubkey_hint_size;
+    uint8_t *image_type_buf;
+    uint16_t image_type;
+    uint8_t image_type_size;
 
     stored_signature_size = get_header(img, HDR_SIGNATURE, &stored_signature);
     if (stored_signature_size != IMAGE_SIGNATURE_SIZE)
@@ -276,6 +277,15 @@ int wolfBoot_verify_authenticity(struct wolfBoot_image *img)
         if (memcmp(digest, pubkey_hint, SHA256_DIGEST_SIZE) != 0)
             return -1;
     }
+    image_type_size = get_header(img, HDR_IMG_TYPE, &image_type_buf);
+    if (image_type_size != sizeof(uint16_t))
+            return -1;
+    image_type = (uint16_t)(image_type_buf[0] + (image_type_buf[1] << 8));
+
+    if ((image_type & 0xFF00) != HDR_IMG_TYPE_AUTH)
+        return -1;
+
+
     if (image_hash(img, digest) != 0)
         return -1;
     if (wolfBoot_verify_signature(digest, stored_signature) != 0)

src/loader.c

@@ -22,8 +22,13 @@
 #include "image.h"
 #include "hal.h"
 #include "spi_flash.h"
+#include "wolfboot/wolfboot.h"
 
-extern void do_boot(const uint32_t *app_offset);
+#ifdef RAM_CODE
+extern unsigned int _start_text;
+static volatile const uint32_t wolfboot_version = WOLFBOOT_VERSION;
+extern void (** const IV_RAM)(void);
+#endif
 
 #define FLASHBUFFER_SIZE 256
 static int wolfBoot_copy_sector(struct wolfBoot_image *src, struct wolfBoot_image *dst, uint32_t sector)
@@ -87,10 +92,16 @@ static int wolfBoot_update(int fallback_allowed)
     /* Check the first sector to detect interrupted update */
     if ((wolfBoot_get_sector_flag(PART_UPDATE, 0, &flag) < 0) || (flag == SECT_FLAG_NEW))
     {
+        uint8_t *update_type;
         /* In case this is a new update, do the required
          * checks on the firmware update
          * before starting the swap
          */
+
+        if (wolfBoot_find_header(update.hdr + IMAGE_HEADER_OFFSET, HDR_IMG_TYPE, &update_type) == sizeof(uint16_t)) {
+            if ((update_type[0] != HDR_IMG_TYPE_APP) || update_type[1] != (HDR_IMG_TYPE_AUTH >> 8))
+                return -1;
+        }
         if (!update.hdr_ok || (wolfBoot_verify_integrity(&update) < 0)
                 || (wolfBoot_verify_authenticity(&update) < 0)) {
             return -1;
@@ -153,11 +164,89 @@ static int wolfBoot_update(int fallback_allowed)
     return 0;
 }
 
+
+#ifdef RAM_CODE
+
+static void RAMFUNCTION wolfBoot_erase_bootloader(void)
+{
+    uint32_t *start = (uint32_t *)&_start_text;
+    uint32_t len = WOLFBOOT_PARTITION_BOOT_ADDRESS - (uint32_t)start;
+    hal_flash_erase((uint32_t)start, len);
+
+}
+
+static void RAMFUNCTION wolfBoot_self_update(struct wolfBoot_image *src)
+{
+    uint32_t pos = 0;
+    uint32_t src_offset = IMAGE_HEADER_SIZE;
+
+    hal_flash_unlock();
+    wolfBoot_erase_bootloader();
+#ifdef EXT_FLASH
+    while (pos < src->fw_size) {
+        if (PART_IS_EXT(src)) {
+            uint8_t buffer[FLASHBUFFER_SIZE];
+            if (src_offset + pos < (src->fw_size + IMAGE_HEADER_SIZE + FLASHBUFFER_SIZE))  {
+                ext_flash_read((uint32_t)(src->hdr) + src_offset + pos, (void *)buffer, FLASHBUFFER_SIZE);
+                hal_flash_write(pos + (uint32_t)&_start_text, buffer, FLASHBUFFER_SIZE);
+            }
+            pos += FLASHBUFFER_SIZE;
+        }
+        goto lock_and_reset;
+    }
+#endif
+    while (pos < src->fw_size) {
+        if (src_offset + pos < (src->fw_size + IMAGE_HEADER_SIZE + FLASHBUFFER_SIZE))  {
+            uint8_t *orig = (uint8_t*)(src->hdr + src_offset + pos);
+            hal_flash_write(pos + (uint32_t)&_start_text, orig, FLASHBUFFER_SIZE);
+        }
+        pos += FLASHBUFFER_SIZE;
+    }
+
+lock_and_reset:
+    hal_flash_lock();
+    arch_reboot();
+}
+
+static void wolfBoot_check_self_update(void)
+{
+    uint8_t st;
+    struct wolfBoot_image update;
+    uint8_t *update_type;
+    uint32_t update_version;
+
+    /* Check for self update in the UPDATE partition */
+    if ((wolfBoot_get_partition_state(PART_UPDATE, &st) == 0) && (st == IMG_STATE_UPDATING) &&
+            (wolfBoot_open_image(&update, PART_UPDATE) == 0) &&
+            (wolfBoot_find_header(update.hdr + IMAGE_HEADER_OFFSET, HDR_IMG_TYPE, &update_type) == sizeof(uint16_t)) &&
+            update_type[0] == HDR_IMG_TYPE_WOLFBOOT &&
+            update_type[1] == (HDR_IMG_TYPE_AUTH >> 8)) {
+        uint32_t update_version = wolfBoot_update_firmware_version();
+        if (update_version <= wolfboot_version) {
+            hal_flash_unlock();
+            wolfBoot_erase_partition(PART_UPDATE);
+            hal_flash_lock();
+            return;
+        }
+        if (wolfBoot_verify_integrity(&update) < 0)
+            return;
+        if (wolfBoot_verify_authenticity(&update) < 0)
+            return;
+        wolfBoot_self_update(&update);
+    }
+}
+#endif /* RAM_CODE for self_update */
+
 static void wolfBoot_start(void)
 {
     uint8_t st;
     struct wolfBoot_image boot, update;
-    /* First, check if the BOOT partition is still in TESTING,
+
+#ifdef RAM_CODE
+    wolfBoot_check_self_update();
+#endif
+
+    /* Check if the BOOT partition is still in TESTING,
      * to trigger fallback.
      */
     if ((wolfBoot_get_partition_state(PART_BOOT, &st) == 0) && (st == IMG_STATE_TESTING)) {