Merge pull request #34 from wolfSSL/rsa-4096

Added RSA-4096 bit support

Author: dgarske

.gitignore

@@ -53,6 +53,7 @@
 src/ed25519_pub_key.c
 src/ecc256_pub_key.c
 src/rsa2048_pub_key.c
+src/rsa4096_pub_key.c
 
 # keygen binaries
 tools/ed25519/ed25519_sign

Makefile

@@ -20,6 +20,9 @@ OBJS:= \
 WOLFCRYPT_OBJS:=
 PUBLIC_KEY_OBJS:=
 
+ifeq ($(SIGN),RSA4096)
+  SPMATH=0
+endif
 
 ## Architecture/CPU configuration
 include arch.mk
@@ -77,6 +80,25 @@ ifeq ($(SIGN),RSA2048)
 		  -Wstack-usage=12288 -DIMAGE_HEADER_SIZE=512
 endif
 
+ifeq ($(SIGN),RSA4096)
+  KEYGEN_OPTIONS=--rsa4096
+  SIGN_OPTIONS=--rsa4096
+  PRIVATE_KEY=rsa4096.der
+  IMAGE_HEADER_SIZE=1024
+  WOLFCRYPT_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 \
+	./lib/wolfssl/wolfcrypt/src/wolfmath.o \
+	./src/xmalloc_rsa.o
+  PUBLIC_KEY_OBJS=./src/rsa4096_pub_key.o
+  CFLAGS+=-DWOLFBOOT_SIGN_RSA4096 -DXMALLOC_USER $(RSA_EXTRA_CFLAGS) \
+		  -Wstack-usage=12288 -DIMAGE_HEADER_SIZE=1024
+endif
+
 
 CFLAGS+=-Wall -Wextra -Wno-main -ffreestanding -Wno-unused \
 	-I. -Iinclude/ -Ilib/wolfssl -nostartfiles \
@@ -201,6 +223,9 @@ ecc256.der:
 rsa2048.der:
 	@python3 tools/keytools/keygen.py $(KEYGEN_OPTIONS) src/rsa2048_pub_key.c
 
+rsa4096.der:
+	@python3 tools/keytools/keygen.py $(KEYGEN_OPTIONS) src/rsa4096_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
@@ -222,6 +247,8 @@ src/ecc256_pub_key.c: ecc256.der
 
 src/rsa2048_pub_key.c: rsa2048.der
 
+src/rsa4096_pub_key.c: rsa4096.der
+
 keys: $(PRIVATE_KEY)
 
 clean:

arch.mk

@@ -4,7 +4,7 @@
 ifeq ($(SPMATH),1)
   MATH_OBJS:=./lib/wolfssl/wolfcrypt/src/sp_int.o
 else
-  MATH_OBJS:=./lib/wolfssl/wolfcrypt/src/integer.o
+  MATH_OBJS:=./lib/wolfssl/wolfcrypt/src/integer.o ./lib/wolfssl/wolfcrypt/src/tfm.o
 endif
 
 # Default flash offset

include/loader.h

@@ -43,6 +43,12 @@
 #   define KEY_BUFFER  rsa2048_pub_key
 #   define KEY_LEN     rsa2048_pub_key_len
 #   define IMAGE_SIGNATURE_SIZE (256)
+#elif defined(WOLFBOOT_SIGN_RSA4096)
+    extern const unsigned char rsa4096_pub_key[];
+    extern unsigned int rsa4096_pub_key_len;
+#   define KEY_BUFFER  rsa4096_pub_key
+#   define KEY_LEN     rsa4096_pub_key_len
+#   define IMAGE_SIGNATURE_SIZE (512)
 #else
 #   error "No public key available for given signing algorithm."
 #endif /* Algorithm selection */

include/user_settings.h

@@ -34,6 +34,7 @@
 //#define TFM_TIMING_RESISTANT
 #define SIZEOF_LONG_LONG 8
 
+
 /* ED25519 and SHA512 */
 #ifdef WOLFBOOT_SIGN_ED25519
 #   define HAVE_ED25519
@@ -97,6 +98,16 @@
 #  define WOLFSSL_SP_NO_3072
 #endif
 
+#ifdef WOLFBOOT_SIGN_RSA4096
+#  define HAVE_RSA
+#  define RSA_LOW_MEM
+#  define WOLFSSL_RSA_VERIFY_INLINE
+#  define FP_MAX_BITS (4096 * 2)
+#  define WC_RSA_BLINDING
+#  define USE_FAST_MATH
+#  define TFM_TIMING_RESISTANT
+#endif
+
 /* Disables - For minimum wolfCrypt build */
 #define NO_AES
 #define NO_CMAC

include/wolfboot/wolfboot.h

@@ -49,6 +49,7 @@
 #define HDR_IMG_TYPE_AUTH_ED25519 0x0100
 #define HDR_IMG_TYPE_AUTH_ECC256  0x0200
 #define HDR_IMG_TYPE_AUTH_RSA2048 0x0300
+#define HDR_IMG_TYPE_AUTH_RSA4096 0x0400
 #define HDR_IMG_TYPE_WOLFBOOT     0x0000
 #define HDR_IMG_TYPE_APP          0x0001
 
@@ -60,6 +61,8 @@
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_ECC256
  #elif defined(WOLFBOOT_SIGN_RSA2048)
  #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_RSA2048
+ #elif defined(WOLFBOOT_SIGN_RSA4096)
+ #   define HDR_IMG_TYPE_AUTH HDR_IMG_TYPE_AUTH_RSA4096
  #else
  #   error "no valid authentication mechanism selected. Please define WOLFBOOT_SIGN_ED25519 or WOLFBOOT_SIGN_ECC256 or WOLFBOOT_SIGN_RSA2048"
  #endif /* defined WOLFBOOT_SIGN_ECC256 || WOLFBOOT_SIGN_ED25519 */

src/image.c

@@ -90,11 +90,17 @@ static int wolfBoot_verify_signature(uint8_t *hash, uint8_t *sig)
 }
 #endif /* WOLFBOOT_SIGN_ECC256 */
 
-#ifdef WOLFBOOT_SIGN_RSA2048
+#if defined(WOLFBOOT_SIGN_RSA2048) || defined (WOLFBOOT_SIGN_RSA4096)
 #include <wolfssl/wolfcrypt/rsa.h>
 #include <wolfssl/wolfcrypt/asn_public.h>
-#define RSA_MAX_KEY_SIZE 256
-#define RSA_SIG_SIZE 256
+
+#ifdef WOLFBOOT_SIGN_RSA4096
+#   define RSA_MAX_KEY_SIZE 512
+#   define RSA_SIG_SIZE 512
+#else
+#   define RSA_MAX_KEY_SIZE 256
+#   define RSA_SIG_SIZE 256
+#endif
 
 static int wolfBoot_verify_signature(uint8_t *hash, uint8_t *sig)
 {

test-app/Makefile

@@ -8,6 +8,10 @@ ifeq ($(SIGN),RSA2048)
   IMAGE_HEADER_SIZE:=512
 endif
 
+ifeq ($(SIGN),RSA4096)
+  IMAGE_HEADER_SIZE:=1024
+endif
+
 CFLAGS:=-g -ggdb -Wall -Wstack-usage=1024 -ffreestanding -Wno-unused -DPLATFORM_$(TARGET) -I../include -nostartfiles
 
 APP_OBJS:=app_$(TARGET).o led.o system.o timer.o ../hal/$(TARGET).o ../src/libwolfboot.o

tools/keytools/keygen.py

@@ -33,20 +33,21 @@
 
 Ed25519_pub_key_define = "const uint8_t ed25519_pub_key[32] = {\n\t"
 Ecc256_pub_key_define = "const uint8_t ecc256_pub_key[64] = {\n\t"
-Rsa_pub_key_define = "const uint8_t rsa2048_pub_key[%d] = {\n\t"
+Rsa_2048_pub_key_define = "const uint8_t rsa2048_pub_key[%d] = {\n\t"
+Rsa_4096_pub_key_define = "const uint8_t rsa4096_pub_key[%d] = {\n\t"
 
 sign="ed25519"
 
 argc = len(sys.argv)
 argv = sys.argv
 
 if (argc < 2) or (argc > 3):
-    print("Usage: %s [--ed25519 | --ecc256 | --rsa2048 ] pub_key_file.c\n" % sys.argv[0])
+    print("Usage: %s [--ed25519 | --ecc256 | --rsa2048 | --rsa4096 ] pub_key_file.c\n" % sys.argv[0])
     sys.exit(1)
 
 if argc == 3:
-    if argv[1] != '--ed25519' and argv[1] != '--ecc256' and argv[1] != '--rsa2048':
-        print("Usage: %s [--ed25519 | --ecc256 | --rsa2048] pub_key_file.c\n" % sys.argv[0])
+    if argv[1] != '--ed25519' and argv[1] != '--ecc256' and argv[1] != '--rsa2048' and argv[1] != '--rsa4096':
+        print("Usage: %s [--ed25519 | --ecc256 | --rsa2048 | --rsa4096] pub_key_file.c\n" % sys.argv[0])
         sys.exit(1)
     sign=argv[1][2:]
     pubkey_cfile = argv[2]
@@ -130,7 +131,6 @@
         f.write("const uint32_t ecc256_pub_key_len = 64;\n")
         f.close()
 
-
 if (sign == "rsa2048"):
     rsa = ciphers.RsaPrivate.make_key(2048)
     if os.path.exists(key_file):
@@ -148,7 +148,7 @@
     print("Creating file " + pubkey_cfile)
     with open(pubkey_cfile, "w") as f:
         f.write(Cfile_Banner)
-        f.write(Rsa_pub_key_define % len(pub))
+        f.write(Rsa_2048_pub_key_define % len(pub))
         i = 0
         for c in bytes(pub):
             f.write("0x%02X, " % c)
@@ -158,3 +158,31 @@
         f.write("\n};\n")
         f.write("const uint32_t rsa2048_pub_key_len = %d;\n" % len(pub))
         f.close()
+
+if (sign == "rsa4096"):
+    rsa = ciphers.RsaPrivate.make_key(4096)
+    if os.path.exists(key_file):
+        choice = input("** Warning: key file already exist! Are you sure you want to "+
+                "generate a new key and overwrite the existing key? [Type 'Yes, I am sure!']: ")
+        if (choice != "Yes, I am sure!"):
+            print("Operation canceled.")
+            sys.exit(2)
+    priv,pub = rsa.encode_key()
+    print()
+    print("Creating file " + key_file)
+    with open(key_file, "wb") as f:
+        f.write(priv)
+        f.close()
+    print("Creating file " + pubkey_cfile)
+    with open(pubkey_cfile, "w") as f:
+        f.write(Cfile_Banner)
+        f.write(Rsa_4096_pub_key_define % len(pub))
+        i = 0
+        for c in bytes(pub):
+            f.write("0x%02X, " % c)
+            i += 1
+            if (i % 8 == 0):
+                f.write('\n')
+        f.write("\n};\n")
+        f.write("const uint32_t rsa4096_pub_key_len = %d;\n" % len(pub))
+        f.close()

tools/keytools/sign.py

@@ -46,6 +46,7 @@
 HDR_IMG_TYPE_AUTH_ED25519 = 0x0100
 HDR_IMG_TYPE_AUTH_ECC256  = 0x0200
 HDR_IMG_TYPE_AUTH_RSA2048 = 0x0300
+HDR_IMG_TYPE_AUTH_RSA4096 = 0x0400
 
 HDR_IMG_TYPE_WOLFBOOT     = 0x0000
 HDR_IMG_TYPE_APP          = 0x0001
@@ -59,7 +60,7 @@
 argv = sys.argv
 
 if (argc < 4) or (argc > 6):
-    print("Usage: %s [--ed25519 | --ecc256 | --rsa2048 ] [--wolfboot-update] image key.der fw_version\n" % sys.argv[0])
+    print("Usage: %s [--ed25519 | --ecc256 | --rsa2048 | --rsa4096 ] [--wolfboot-update] image key.der fw_version\n" % sys.argv[0])
     sys.exit(1)
 for i in range(1, len(argv)):
     if (argv[i] == '--ed25519'):
@@ -68,6 +69,8 @@
         sign='ecc256'
     elif (argv[i] == '--rsa2048'):
         sign='rsa2048'
+    elif (argv[i] == '--rsa4096'):
+        sign='rsa4096'
     elif (argv[i] == '--wolfboot-update'):
         self_update = True
     else:
@@ -114,6 +117,9 @@
     if sign == 'auto':
         sign = 'ecc256'
         print("'ecc256' key autodetected.")
+elif (wolfboot_private_key_len > 512):
+    if (sign == 'auto'):
+        print("'rsa4096' key autodetected.")
 elif (wolfboot_private_key_len > 128):
     if (sign == 'auto'):
         print("'rsa2048' key autodetected.")
@@ -134,16 +140,22 @@
     pubkey = wolfboot_private_key[0:64]
 
 if sign == 'rsa2048':
-    WOLFBOOT_HEADER_SIZE = 512 
+    WOLFBOOT_HEADER_SIZE = 512
     HDR_SIGNATURE_LEN = 256
     rsa = ciphers.RsaPrivate(wolfboot_private_key)
     privkey,pubkey = rsa.encode_key()
 
+if sign == 'rsa4096':
+    WOLFBOOT_HEADER_SIZE = 1024
+    HDR_SIGNATURE_LEN = 512
+    rsa = ciphers.RsaPrivate(wolfboot_private_key)
+    privkey,pubkey = rsa.encode_key()
+
 
 img_size = os.path.getsize(image_file)
 # Magic header (spells 'WOLF')
 header = struct.pack('<L', WOLFBOOT_MAGIC)
-# Image size 
+# Image size
 header += struct.pack('<L', img_size)
 
 # No pad bytes, version is aligned
@@ -168,6 +180,8 @@
     img_type = HDR_IMG_TYPE_AUTH_ECC256
 if (sign == 'rsa2048'):
     img_type = HDR_IMG_TYPE_AUTH_RSA2048
+if (sign == 'rsa4096'):
+    img_type = HDR_IMG_TYPE_AUTH_RSA4096
 
 if (not self_update):
     img_type |= HDR_IMG_TYPE_APP
@@ -209,7 +223,7 @@
 elif (sign == 'ecc256'):
     r, s = ecc.sign_raw(digest)
     signature = r + s
-elif (sign == 'rsa2048'):
+elif (sign == 'rsa2048') or (sign == 'rsa4096'):
     signature = rsa.sign(digest)
     #plain = rsa.verify(signature)
     #print("plain:%d " % len(plain))