Add Zephyr infrastructure for ed25519
Signed-off-by: Fabio Utzig <utzig@apache.org>
diff --git a/boot/zephyr/CMakeLists.txt b/boot/zephyr/CMakeLists.txt
index cb4feca..55ba173 100644
--- a/boot/zephyr/CMakeLists.txt
+++ b/boot/zephyr/CMakeLists.txt
@@ -62,6 +62,9 @@
# Path to tinycrypt library source subdirectory of MCUBOOT_DIR.
set(TINYCRYPT_DIR "${MCUBOOT_DIR}/ext/tinycrypt/lib")
assert_exists(TINYCRYPT_DIR)
+# Path to crypto-fiat
+set(FIAT_DIR "${MCUBOOT_DIR}/ext/fiat")
+assert_exists(FIAT_DIR)
# Path to mbed-tls' asn1 parser library.
set(MBEDTLS_ASN1_DIR "${MCUBOOT_DIR}/ext/mbedtls")
assert_exists(MBEDTLS_ASN1_DIR)
@@ -105,6 +108,7 @@
${BOOT_DIR}/bootutil/src/encrypted.c
${BOOT_DIR}/bootutil/src/image_rsa.c
${BOOT_DIR}/bootutil/src/image_ec256.c
+ ${BOOT_DIR}/bootutil/src/image_ed25519.c
${BOOT_DIR}/bootutil/src/caps.c
)
@@ -146,6 +150,18 @@
# Use mbedTLS provided by Zephyr for RSA signatures. (Its config file
# is set using Kconfig.)
zephyr_include_directories(include)
+elseif(CONFIG_BOOT_SIGNATURE_TYPE_ED25519)
+ # For ed25519, mbedTLS is used for ASN1 parsing and SHA512
+ zephyr_include_directories(include)
+
+ zephyr_library_include_directories(
+ ${BOOT_DIR}/zephyr/include
+ ${FIAT_DIR}/include/
+ )
+
+ zephyr_library_sources(
+ ${FIAT_DIR}/src/curve25519.c
+ )
endif()
if(CONFIG_MCUBOOT_SERIAL)
diff --git a/boot/zephyr/Kconfig b/boot/zephyr/Kconfig
index 3de379f..d00cbbc 100644
--- a/boot/zephyr/Kconfig
+++ b/boot/zephyr/Kconfig
@@ -76,6 +76,11 @@
config BOOT_SIGNATURE_TYPE_ECDSA_P256
bool "Elliptic curve digital signatures with curve P-256"
+config BOOT_SIGNATURE_TYPE_ED25519
+ bool "Edwards curve digital signatures using ed25519"
+ select BOOT_USE_MBEDTLS
+ select MBEDTLS
+
if BOOT_SIGNATURE_TYPE_ECDSA_P256
choice
prompt "Ecdsa implementation"
diff --git a/boot/zephyr/include/config-ed25519.h b/boot/zephyr/include/config-ed25519.h
new file mode 100644
index 0000000..fb0750a
--- /dev/null
+++ b/boot/zephyr/include/config-ed25519.h
@@ -0,0 +1,76 @@
+/*
+ * Configuration of mbedTLS containing only the ASN.1 parser.
+ *
+ * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ * Copyright (C) 2016, Linaro Ltd
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+/*
+ * Minimal configuration for using TLS in the bootloader
+ *
+ * - ed25519 signature verification
+ */
+
+#ifndef MCUBOOT_MBEDTLS_CONFIG_ED25519
+#define MCUBOOT_MBEDTLS_CONFIG_ED25519
+
+#ifdef CONFIG_MCUBOOT_SERIAL
+/* Mcuboot uses mbedts-base64 for serial protocol encoding. */
+#define MBEDTLS_BASE64_C
+#endif
+
+/* System support */
+#define MBEDTLS_PLATFORM_C
+#define MBEDTLS_PLATFORM_MEMORY
+#define MBEDTLS_MEMORY_BUFFER_ALLOC_C
+#define MBEDTLS_NO_PLATFORM_ENTROPY
+#define MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES
+
+/* STD functions */
+#define MBEDTLS_PLATFORM_NO_STD_FUNCTIONS
+
+#define MBEDTLS_PLATFORM_EXIT_ALT
+#define MBEDTLS_PLATFORM_PRINTF_ALT
+#define MBEDTLS_PLATFORM_SNPRINTF_ALT
+
+#if !defined(CONFIG_ARM)
+#define MBEDTLS_HAVE_ASM
+#endif
+
+/* mbed TLS modules */
+#define MBEDTLS_ASN1_PARSE_C
+#define MBEDTLS_BIGNUM_C
+#define MBEDTLS_MD_C
+#define MBEDTLS_OID_C
+#define MBEDTLS_SHA256_C
+#define MBEDTLS_SHA512_C
+#define MBEDTLS_AES_C
+
+/* Save RAM by adjusting to our exact needs */
+//#define MBEDTLS_ECP_MAX_BITS 2048
+
+#define MBEDTLS_MPI_MAX_SIZE 64
+
+//#define MBEDTLS_SSL_MAX_CONTENT_LEN 1024
+
+/* Save ROM and a few bytes of RAM by specifying our own ciphersuite list */
+#define MBEDTLS_SSL_CIPHERSUITES MBEDTLS_TLS_ECJPAKE_WITH_AES_128_CCM_8
+
+#include "mbedtls/check_config.h"
+
+#endif /* MCUBOOT_MBEDTLS_CONFIG_RSA */
diff --git a/boot/zephyr/include/mcuboot-mbedtls-cfg.h b/boot/zephyr/include/mcuboot-mbedtls-cfg.h
index 00f90e8..b15d5ac 100644
--- a/boot/zephyr/include/mcuboot-mbedtls-cfg.h
+++ b/boot/zephyr/include/mcuboot-mbedtls-cfg.h
@@ -25,6 +25,8 @@
#include "config-rsa.h"
#elif defined(CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256)
#include "config-asn1.h"
+#elif defined(CONFIG_BOOT_SIGNATURE_TYPE_ED25519)
+#include "config-ed25519.h"
#else
#error "Cannot configure mbedTLS; signature type is unknown."
#endif
diff --git a/boot/zephyr/include/mcuboot_config/mcuboot_config.h b/boot/zephyr/include/mcuboot_config/mcuboot_config.h
index 7f110dd..4365ed2 100644
--- a/boot/zephyr/include/mcuboot_config/mcuboot_config.h
+++ b/boot/zephyr/include/mcuboot_config/mcuboot_config.h
@@ -28,6 +28,8 @@
# endif
#elif defined(CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256)
#define MCUBOOT_SIGN_EC256
+#elif defined(CONFIG_BOOT_SIGNATURE_TYPE_ED25519)
+#define MCUBOOT_SIGN_ED25519
#endif
#ifdef CONFIG_BOOT_USE_MBEDTLS
diff --git a/boot/zephyr/keys.c b/boot/zephyr/keys.c
index d59afdb..ee61c7d 100644
--- a/boot/zephyr/keys.c
+++ b/boot/zephyr/keys.c
@@ -36,6 +36,10 @@
#define HAVE_KEYS
extern const unsigned char ecdsa_pub_key[];
extern unsigned int ecdsa_pub_key_len;
+#elif defined(MCUBOOT_SIGN_ED25519)
+#define HAVE_KEYS
+extern const unsigned char ed25519_pub_key[];
+extern unsigned int ed25519_pub_key_len;
#else
#error "No public key available for given signing algorithm."
#endif
@@ -54,6 +58,9 @@
#elif defined(MCUBOOT_SIGN_EC256)
.key = ecdsa_pub_key,
.len = &ecdsa_pub_key_len,
+#elif defined(MCUBOOT_SIGN_ED25519)
+ .key = ed25519_pub_key,
+ .len = &ed25519_pub_key_len,
#endif
},
};
diff --git a/boot/zephyr/prj.conf b/boot/zephyr/prj.conf
index 4a179d3..dd67333 100644
--- a/boot/zephyr/prj.conf
+++ b/boot/zephyr/prj.conf
@@ -14,6 +14,7 @@
CONFIG_BOOT_SIGNATURE_TYPE_RSA=y
CONFIG_BOOT_SIGNATURE_TYPE_RSA_LEN=2048
CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256=n
+CONFIG_BOOT_SIGNATURE_TYPE_ED25519=n
### The bootloader generates its own signature verification based on a
### key file which needs to be provided and needs to match the selected signing
@@ -22,6 +23,7 @@
CONFIG_BOOT_SIGNATURE_KEY_FILE="root-rsa-2048.pem"
#CONFIG_BOOT_SIGNATURE_KEY_FILE="root-rsa-3072.pem"
#CONFIG_BOOT_SIGNATURE_KEY_FILE="root-ec-p256.pem"
+#CONFIG_BOOT_SIGNATURE_KEY_FILE="root-ed25519.pem"
### mbedTLS has its own heap
# CONFIG_HEAP_MEM_POOL_SIZE is not set