Adds RSA support to wolfBoot using "SIGN=RSA2048". Includes RSA signing script tool in Python and instructions.

Author: dgarske

.gitignore

@@ -52,6 +52,7 @@
 # automatically generated source files
 src/ed25519_pub_key.c
 src/ecc256_pub_key.c
+src/rsa2048_pub_key.c
 
 # keygen binaries
 tools/ed25519/ed25519_sign

Makefile

@@ -8,27 +8,21 @@
 include tools/config.mk
 
 ## Initializers
-CFLAGS:=-D__WOLFBOOT  -DWOLFBOOT_VERSION=$(WOLFBOOT_VERSION)UL -ffunction-sections -fdata-sections
+CFLAGS:=-D__WOLFBOOT -DWOLFBOOT_VERSION=$(WOLFBOOT_VERSION)UL -ffunction-sections -fdata-sections
 LSCRIPT:=config/target.ld
 LDFLAGS:=-T $(LSCRIPT) -Wl,-gc-sections -Wl,-Map=wolfboot.map -ffreestanding -nostartfiles
 OBJS:= \
 ./hal/$(TARGET).o \
 ./src/loader.o \
 ./src/string.o \
 ./src/image.o \
-./src/libwolfboot.o \
-./lib/wolfssl/wolfcrypt/src/sha256.o \
-./lib/wolfssl/wolfcrypt/src/hash.o \
-./lib/wolfssl/wolfcrypt/src/wolfmath.o \
-./lib/wolfssl/wolfcrypt/src/fe_low_mem.o
+./src/libwolfboot.o
 
 
 ## Architecture/CPU configuration
 include arch.mk
 
-
 ## DSA Settings
-
 ifeq ($(SIGN),ECC256)
   KEYGEN_OPTIONS=--ecc256
   SIGN_OPTIONS=--ecc256
@@ -37,26 +31,53 @@ ifeq ($(SIGN),ECC256)
     $(ECC_EXTRA_OBJS) \
     $(MATH_OBJS) \
 	./lib/wolfssl/wolfcrypt/src/ecc.o \
-	./lib/wolfssl/wolfcrypt/src/ge_low_mem.o \
 	./lib/wolfssl/wolfcrypt/src/memory.o \
 	./lib/wolfssl/wolfcrypt/src/wc_port.o \
+    ./lib/wolfssl/wolfcrypt/src/sha256.o \
+    ./lib/wolfssl/wolfcrypt/src/hash.o \
     ./src/ecc256_pub_key.o \
-    ./src/xmalloc.o
-  CFLAGS+=-DWOLFBOOT_SIGN_ECC256 -DXMALLOC_USER $(ECC_EXTRA_CFLAGS)
-else
+    ./src/xmalloc_ecc.o
+  CFLAGS+=-DWOLFBOOT_SIGN_ECC256 -DXMALLOC_USER $(ECC_EXTRA_CFLAGS) \
+		  -Wstack-usage=1024
+endif
+
+ifeq ($(SIGN),ED25519)
   KEYGEN_OPTIONS=--ed25519
   SIGN_OPTIONS=--ed25519
   PRIVATE_KEY=ed25519.der
   OBJS+= ./lib/wolfssl/wolfcrypt/src/sha512.o \
 	./lib/wolfssl/wolfcrypt/src/ed25519.o \
 	./lib/wolfssl/wolfcrypt/src/ge_low_mem.o \
+    ./lib/wolfssl/wolfcrypt/src/sha256.o \
+    ./lib/wolfssl/wolfcrypt/src/hash.o \
+	./lib/wolfssl/wolfcrypt/src/wolfmath.o \
+    ./lib/wolfssl/wolfcrypt/src/fe_low_mem.o \
     ./src/ed25519_pub_key.o
-  CFLAGS+=-DWOLFBOOT_SIGN_ED25519 -nostdlib -DWOLFSSL_STATIC_MEMORY
+  CFLAGS+=-DWOLFBOOT_SIGN_ED25519 -nostdlib -DWOLFSSL_STATIC_MEMORY \
+		  -Wstack-usage=1024
   LDFLAGS+=-nostdlib
 endif
 
+ifeq ($(SIGN),RSA2048)
+  KEYGEN_OPTIONS=--rsa2048
+  SIGN_OPTIONS=--rsa2048
+  PRIVATE_KEY=rsa2048.der
+  IMAGE_HEADER_SIZE=512
+  OBJS+= \
+    $(RSA_EXTRA_OBJS) \
+    $(MATH_OBJS) \
+	./lib/wolfssl/wolfcrypt/src/rsa.o \
+	./lib/wolfssl/wolfcrypt/src/sha256.o \
+	./lib/wolfssl/wolfcrypt/src/asn.o \
+	./lib/wolfssl/wolfcrypt/src/hash.o \
+    ./src/rsa2048_pub_key.o \
+	./src/xmalloc_rsa.o
+  CFLAGS+=-DWOLFBOOT_SIGN_RSA2048 -DXMALLOC_USER $(RSA_EXTRA_CFLAGS) \
+		  -Wstack-usage=4096 -DIMAGE_HEADER_SIZE=512
+endif
+
 
-CFLAGS+=-Wall -Wextra -Wno-main -Wstack-usage=1024 -ffreestanding -Wno-unused \
+CFLAGS+=-Wall -Wextra -Wno-main -ffreestanding -Wno-unused \
 	-I. -Iinclude/ -Ilib/wolfssl -nostartfiles \
 	-DWOLFSSL_USER_SETTINGS \
 	-DPLATFORM_$(TARGET)
@@ -108,15 +129,15 @@ ASFLAGS:=$(CFLAGS)
 all: factory.bin
 
 wolfboot.bin: wolfboot.elf
-	@echo "\t[BIN] $@"	
+	@echo "\t[BIN] $@"
 	$(Q)$(OBJCOPY) -O binary $^ $@
 
 wolfboot.hex: wolfboot.elf
-	@echo "\t[HEX] $@"	
+	@echo "\t[HEX] $@"
 	$(Q)$(OBJCOPY) -O ihex $^ $@
 
 align: wolfboot-align.bin
-	
+
 .bootloader-partition-size: FORCE
 	@printf "%d" $(WOLFBOOT_PARTITION_BOOT_ADDRESS) > .wolfboot-offset
 	@printf "%d" $(ARCH_FLASH_OFFSET) > .wolfboot-arch-offset
@@ -136,6 +157,15 @@ test-app/image.bin: wolfboot-align.bin
 	@rm -f src/*.o hal/*.o
 	@$(SIZE) test-app/image.elf
 
+standalone:
+	@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) standalone
+	$(Q)$(OBJCOPY) -O binary test-app/image.elf standalone.bin
+	@$(SIZE) test-app/image.elf
+
 include tools/test.mk
 
 ed25519.der:
@@ -144,6 +174,9 @@ ed25519.der:
 ecc256.der:
 	@python3 tools/keytools/keygen.py $(KEYGEN_OPTIONS) src/ecc256_pub_key.c
 
+rsa2048.der:
+	@python3 tools/keytools/keygen.py $(KEYGEN_OPTIONS) src/rsa2048_pub_key.c
+
 factory.bin: $(BOOT_IMG) wolfboot-align.bin $(PRIVATE_KEY)
 	@echo "\t[SIGN] $(BOOT_IMG)"
 	$(Q)python3 tools/keytools/sign.py $(SIGN_OPTIONS) $(BOOT_IMG) $(PRIVATE_KEY) 1
@@ -163,15 +196,17 @@ src/ed25519_pub_key.c: ed25519.der
 
 src/ecc256_pub_key.c: ecc256.der
 
+src/rsa2048_pub_key.c: rsa2048.der
+
 keys: $(PRIVATE_KEY)
-	
+
 clean:
 	@find . -type f -name "*.o" | xargs rm -f
 	@rm -f *.bin *.elf wolfboot.map *.bin  *.hex config/target.ld
 	@make -C test-app clean
 
 distclean: clean
-	@rm -f *.pem *.der tags ./src/ed25519_pub_key.c ./src/ecc256_pub_key.c include/target.h
+	@rm -f *.pem *.der tags ./src/ed25519_pub_key.c ./src/ecc256_pub_key.c ./src/rsa2048_pub_key.c include/target.h
 
 include/target.h: include/target.h.in FORCE
 	@cat include/target.h.in | \
@@ -193,6 +228,6 @@ config: FORCE
 	@echo "\t[AS-$(ARCH)] $@"
 	$(Q)$(CC) $(CFLAGS) -c -o $@ $^
 
-FORCE: 
+FORCE:
 
 .PHONY: FORCE clean

README.md

@@ -1,7 +1,7 @@
 # wolfBoot
 wolfSSL Secure Bootloader ([Home page](https://www.wolfssl.com/products/wolfboot/))
 
-wolfBoot is a portable, OS-agnostic, secure bootloader solution for 32-bit microcontrollers, 
+wolfBoot is a portable, OS-agnostic, secure bootloader solution for 32-bit microcontrollers,
 relying on wolfCrypt for firmware authentication, providing firmware update mechanisms.
 
 Due to the minimalist design of the bootloader and the tiny HAL API, wolfBoot is completely independent
@@ -21,8 +21,8 @@ projects to provide a secure firmware update mechanism.
 
 This repository contains the following components:
    - the wolfBoot bootloader
-   - key generator and image signing tools (requires python 3.x)
-   - Baremetal test applications 
+   - key generator and image signing tools (requires python 3.x and wolfcrypt-py https://github.com/wolfSSL/wolfcrypt-py)
+   - Baremetal test applications
 
 ### wolfBoot bootloader
 
@@ -32,7 +32,7 @@ with no dynamic memory allocation mechanism or linkage to any standard C library
 The bootloader consists of the following components:
    - wolfCrypt, which is used to verify the signature of the images
    - A minimalist Hardware Abstraction Layer, with an implementation provided for the supported target, which is in charge for IAP flash access and clock setting on the specific MCU
-   - The core bootloader 
+   - The core bootloader
    - A small application library used by the application to interact with the bootloader [src/libwolfboot.c](src/libwolfboot.c)
 
 Only ARM Cortex-M boot mechanism is supported at this stage. Support for more architectures and
@@ -83,10 +83,48 @@ For detailed information about the configuration options for the target system,
 
 For more detailed information about firmware update implementation, see [Firmware Update](docs/firmware_update.md)
 
+## Troubleshooting
+
+1. Python errors when signing a key:
+
+```
+Traceback (most recent call last):
+  File "tools/keytools/keygen.py", line 135, in <module>
+    rsa = ciphers.RsaPrivate.make_key(2048)
+AttributeError: type object 'RsaPrivate' has no attribute 'make_key'
+```
+
+```
+Traceback (most recent call last):
+  File "tools/keytools/sign.py", line 189, in <module>
+    r, s = ecc.sign_raw(digest)
+AttributeError: 'EccPrivate' object has no attribute 'sign_raw'
+```
+
+You need to install the latest wolfcrypt-pi here: https://github.com/wolfSSL/wolfcrypt-py
+
+Use `pip3 install wolfcrypt`.
+Make sure the wolfSSL library has been built with:
+```sh
+
+```
+
+To install based on a local wolfSSL installation use:
+
+```sh
+cd youwolfssldir
+./configure --enable-keygen --enable-rsa --enable-ecc --enable-ed25519 CFLAGS="-DWOLFSSL_PUBLIC_MP"
+make
+sudo make install
+
+cd yourwolfcryptpydir
+USE_LOCAL_WOLFSSL=/usr/local pip3 install .
+```
+
 ## Release Notes
 
 ### v1.0 (2018-12-04)
- * Initial release with fail-safe update, HAL support for STM32 and nRF52 
+ * Initial release with fail-safe update, HAL support for STM32 and nRF52
 
 ### V1.1 (2019-03-27)
  * Added support for ECC-256 DSA

hal/stm32f4.ld

@@ -15,6 +15,11 @@ SECTIONS
         . = ALIGN(4);
         _end_text = .;
     } > FLASH
+    .edidx :
+    {
+        . = ALIGN(4);
+        *(.ARM.exidx*)
+    } > FLASH
 
     .edidx :
     {

hal/stm32l5.ld

@@ -0,0 +1,44 @@
+MEMORY
+{
+    FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 0x001FFE0
+    RAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0x00010000
+}
+
+SECTIONS
+{
+    .text :
+    {
+        _start_text = .;
+        KEEP(*(.isr_vector))
+        *(.text*)
+        *(.rodata*)
+        . = ALIGN(4);
+        _end_text = .;
+    } > FLASH
+
+    _stored_data = .;
+    .data : AT (_stored_data)
+    {
+        _start_data = .;
+        KEEP(*(.data*))
+        . = ALIGN(4);
+        KEEP(*(.ramcode))
+        . = ALIGN(4);
+        _end_data = .;
+    } > RAM
+
+    .bss (NOLOAD) :
+    {
+        _start_bss = .;
+        __bss_start__ = .;
+        *(.bss*)
+        *(COMMON)
+        . = ALIGN(4);
+        _end_bss = .;
+        __bss_end__ = .;
+        _end = .;
+    } > RAM
+    . = ALIGN(4);
+}
+
+END_STACK = ORIGIN(RAM) + LENGTH(RAM);

hal/stm32wb.ld

@@ -15,7 +15,6 @@ SECTIONS
         . = ALIGN(4);
         _end_text = .;
     } > FLASH
-    
     .edidx :
     {
         . = ALIGN(4);

include/image.h

@@ -70,7 +70,7 @@ 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);
+uint16_t wolfBoot_find_header(uint8_t *haystack, uint16_t type, uint8_t **ptr);
 
 #ifdef EXT_FLASH
 # ifdef PART_UPDATE_EXT

include/loader.h

@@ -37,6 +37,12 @@
 #   define KEY_BUFFER  ecc256_pub_key
 #   define KEY_LEN     ecc256_pub_key_len
 #   define IMAGE_SIGNATURE_SIZE (64)
+#elif defined(WOLFBOOT_SIGN_RSA2048)
+    extern const unsigned char rsa2048_pub_key[];
+    extern unsigned int rsa2048_pub_key_len;
+#   define KEY_BUFFER  rsa2048_pub_key
+#   define KEY_LEN     rsa2048_pub_key_len
+#   define IMAGE_SIGNATURE_SIZE (256)
 #else
 #   error "No public key available for given signing algorithm."
 #endif /* Algorithm selection */

include/user_settings.h

@@ -41,6 +41,8 @@
 #   define NO_ED25519_EXPORT
 #   define WOLFSSL_SHA512
 #   define USE_SLOW_SHA512
+#   define NO_RSA
+#   define NO_ASN
 #endif
 
 /* ECC and SHA256 */
@@ -78,15 +80,29 @@
 #   define NO_ECC224
 #   define HAVE_ECC256
 #   define NO_ECC384
+#   define NO_RSA
+#   define NO_ASN
+#endif
+
+#ifdef WOLFBOOT_SIGN_RSA2048
+#  define HAVE_RSA
+#  define RSA_LOW_MEM
+#  define WOLFSSL_STATIC_RSA
+#  define WOLFSSL_RSA_VERIFY_INLINE
+//#  define WOLFSSL_RSA_PUBLIC_ONLY
+//#  define WOLFSSL_RSA_VERIFY_ONLY
+#  define WOLFSSL_HAVE_SP_RSA
+#  define WOLFSSL_SP
+#  define WOLFSSL_SP_SMALL
+#  define WOLFSSL_SP_MATH
+#  define SP_WORD_SIZE 32
 #endif
 
 /* Disables - For minimum wolfCrypt build */
 #define NO_AES
 #define NO_CMAC
 #define NO_CODING
-#define NO_RSA
 #define NO_BIG_INT
-#define NO_ASN
 #define NO_RC4
 #define NO_SHA
 #define NO_DH