[nrf noup] PSA implementation of x25519 and ed25519 verification

The commit provides implementation of image verification with
ed25519 and encryption/decryption support where random key
is encrypted using x25519.

Signed-off-by: Dominik Ermel <[email protected]>
(cherry picked from commit e874cf8)

Author: de-nordic

boot/bootutil/include/bootutil/crypto/aes_ctr.h

@@ -15,8 +15,8 @@
 #include "mcuboot_config/mcuboot_config.h"
 
 #if (defined(MCUBOOT_USE_MBED_TLS) + \
-     defined(MCUBOOT_USE_TINYCRYPT)) != 1
-    #error "One crypto backend must be defined: either MBED_TLS or TINYCRYPT"
+     defined(MCUBOOT_USE_TINYCRYPT) + defined(MCUBOOT_USE_PSA_CRYPTO)) != 1
+    #error "One crypto backend must be defined: either MBED_TLS or TINYCRYPT or PSA"
 #endif
 
 #if defined(MCUBOOT_USE_MBED_TLS)
@@ -38,12 +38,46 @@
     #define BOOTUTIL_CRYPTO_AES_CTR_BLOCK_SIZE TC_AES_BLOCK_SIZE
 #endif /* MCUBOOT_USE_TINYCRYPT */
 
+
+#if defined(MCUBOOT_USE_PSA_CRYPTO)
+    #include <psa/crypto.h>
+    #include "bootutil/enc_key_public.h"
+    #define BOOTUTIL_CRYPTO_AES_CTR_KEY_SIZE BOOT_ENC_KEY_SIZE
+    #define BOOTUTIL_CRYPTO_AES_CTR_BLOCK_SIZE (16)
+#endif
+
 #include <stdint.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if defined(MCUBOOT_USE_PSA_CRYPTO)
+typedef struct {
+	/* Fixme: This should not be, here, psa_key_id should be passed */
+	uint8_t key[BOOT_ENC_KEY_SIZE];
+} bootutil_aes_ctr_context;
+
+void bootutil_aes_ctr_init(bootutil_aes_ctr_context *ctx);
+
+static inline void bootutil_aes_ctr_drop(bootutil_aes_ctr_context *ctx)
+{
+    memset(ctx, 0, sizeof(ctx));
+}
+
+static inline int bootutil_aes_ctr_set_key(bootutil_aes_ctr_context *ctx, const uint8_t *k)
+{
+    memcpy(ctx->key, k, sizeof(ctx->key));
+
+    return 0;
+}
+
+int bootutil_aes_ctr_encrypt(bootutil_aes_ctr_context *ctx, uint8_t *counter,
+        const uint8_t *m, uint32_t mlen, size_t blk_off, uint8_t *c);
+int bootutil_aes_ctr_decrypt(bootutil_aes_ctr_context *ctx, uint8_t *counter,
+        const uint8_t *c, uint32_t clen, size_t blk_off, uint8_t *m);
+#endif
+
 #if defined(MCUBOOT_USE_MBED_TLS)
 typedef mbedtls_aes_context bootutil_aes_ctr_context;
 static inline void bootutil_aes_ctr_init(bootutil_aes_ctr_context *ctx)

boot/bootutil/src/ed25519_psa.c

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2020 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+#include <assert.h>
+#include <string.h>
+#include <stdint.h>
+
+#include <mcuboot_config/mcuboot_config.h>
+#include "bootutil/bootutil_log.h"
+
+#include <psa/crypto.h>
+#include <psa/crypto_types.h>
+
+BOOT_LOG_MODULE_DECLARE(ed25519_psa);
+
+#define SHA512_DIGEST_LENGTH    64
+#define EDDSA_KEY_LENGTH        32
+#define EDDSA_SIGNAGURE_LENGTH  64
+
+int ED25519_verify(const uint8_t *message, size_t message_len,
+                          const uint8_t signature[EDDSA_SIGNAGURE_LENGTH],
+                          const uint8_t public_key[EDDSA_KEY_LENGTH])
+{
+    /* Set to any error */
+    psa_status_t status = PSA_ERROR_BAD_STATE;
+    psa_key_attributes_t key_attr = PSA_KEY_ATTRIBUTES_INIT;
+    psa_key_id_t kid;
+    int ret = 0;        /* Fail by default */
+
+    /* Initialize PSA Crypto */
+    status = psa_crypto_init();
+    if (status != PSA_SUCCESS) {
+        BOOT_LOG_ERR("PSA crypto init failed %d\n", status);
+        return 0;
+    }
+
+    status = PSA_ERROR_BAD_STATE;
+
+    psa_set_key_type(&key_attr,
+                     PSA_KEY_TYPE_ECC_PUBLIC_KEY(PSA_ECC_FAMILY_TWISTED_EDWARDS));
+    psa_set_key_usage_flags(&key_attr, PSA_KEY_USAGE_VERIFY_MESSAGE);
+    psa_set_key_algorithm(&key_attr, PSA_ALG_PURE_EDDSA);
+
+    status = psa_import_key(&key_attr, public_key, EDDSA_KEY_LENGTH, &kid);
+    if (status != PSA_SUCCESS) {
+        BOOT_LOG_ERR("ED25519 key import failed %d", status);
+        return 0;
+    }
+
+    status = psa_verify_message(kid, PSA_ALG_PURE_EDDSA, message, message_len,
+                                signature, EDDSA_SIGNAGURE_LENGTH);
+    if (status != PSA_SUCCESS) {
+        BOOT_LOG_ERR("ED25519 signature verification failed %d", status);
+        ret = 0;
+        /* Pass through to destroy key */
+    } else {
+	ret = 1;
+        /* Pass through to destroy key */
+    }
+
+    status = psa_destroy_key(kid);
+
+    if (status != PSA_SUCCESS) {
+        /* Just for logging */
+        BOOT_LOG_WRN("Failed to destroy key %d", status);
+    }
+
+    return ret;
+}

boot/bootutil/src/encrypted.c

@@ -25,6 +25,7 @@
 #include "bootutil/crypto/ecdh_p256.h"
 #endif
 
+#if !defined(MCUBOOT_USE_PSA_CRYPTO)
 #if defined(MCUBOOT_ENCRYPT_X25519)
 #include "bootutil/crypto/ecdh_x25519.h"
 #endif
@@ -35,6 +36,7 @@
 #include "mbedtls/oid.h"
 #include "mbedtls/asn1.h"
 #endif
+#endif
 
 #include "bootutil/image.h"
 #include "bootutil/enc_key.h"
@@ -43,6 +45,30 @@
 
 #include "bootutil_priv.h"
 
+#define EXPECTED_ENC_LEN        BOOT_ENC_TLV_SIZE
+
+#if defined(MCUBOOT_ENCRYPT_RSA)
+#    define EXPECTED_ENC_TLV    IMAGE_TLV_ENC_RSA2048
+#elif defined(MCUBOOT_ENCRYPT_KW)
+#    define EXPECTED_ENC_TLV    IMAGE_TLV_ENC_KW
+#elif defined(MCUBOOT_ENCRYPT_EC256)
+#    define EXPECTED_ENC_TLV    IMAGE_TLV_ENC_EC256
+#    define EC_PUBK_INDEX       (0)
+#    define EC_TAG_INDEX        (65)
+#    define EC_CIPHERKEY_INDEX  (65 + 32)
+_Static_assert(EC_CIPHERKEY_INDEX + BOOT_ENC_KEY_SIZE == EXPECTED_ENC_LEN,
+        "Please fix ECIES-P256 component indexes");
+#elif defined(MCUBOOT_ENCRYPT_X25519)
+#    define EXPECTED_ENC_TLV    IMAGE_TLV_ENC_X25519
+#    define EC_PUBK_INDEX       (0)
+#    define EC_TAG_INDEX        (32)
+#    define EC_CIPHERKEY_INDEX  (32 + 32)
+_Static_assert(EC_CIPHERKEY_INDEX + BOOT_ENC_KEY_SIZE == EXPECTED_ENC_LEN,
+        "Please fix ECIES-X25519 component indexes");
+#endif
+
+/* NOUP Fixme:  */
+#if !defined(CONFIG_BOOT_ED25519_PSA)
 #if defined(MCUBOOT_ENCRYPT_EC256) || defined(MCUBOOT_ENCRYPT_X25519)
 #if defined(_compare)
 static inline int bootutil_constant_time_compare(const uint8_t *a, const uint8_t *b, size_t size)
@@ -351,60 +377,6 @@ int boot_enc_retrieve_private_key(struct bootutil_key **private_key)
 }
 #endif /* !MCUBOOT_ENC_BUILTIN_KEY */
 
-int
-boot_enc_init(struct enc_key_data *enc_state, uint8_t slot)
-{
-    bootutil_aes_ctr_init(&enc_state[slot].aes_ctr);
-    return 0;
-}
-
-int
-boot_enc_drop(struct enc_key_data *enc_state, uint8_t slot)
-{
-    bootutil_aes_ctr_drop(&enc_state[slot].aes_ctr);
-    enc_state[slot].valid = 0;
-    return 0;
-}
-
-int
-boot_enc_set_key(struct enc_key_data *enc_state, uint8_t slot,
-        const struct boot_status *bs)
-{
-    int rc;
-
-    rc = bootutil_aes_ctr_set_key(&enc_state[slot].aes_ctr, bs->enckey[slot]);
-    if (rc != 0) {
-        boot_enc_drop(enc_state, slot);
-        return -1;
-    }
-
-    enc_state[slot].valid = 1;
-
-    return 0;
-}
-
-#define EXPECTED_ENC_LEN        BOOT_ENC_TLV_SIZE
-
-#if defined(MCUBOOT_ENCRYPT_RSA)
-#    define EXPECTED_ENC_TLV    IMAGE_TLV_ENC_RSA2048
-#elif defined(MCUBOOT_ENCRYPT_KW)
-#    define EXPECTED_ENC_TLV    IMAGE_TLV_ENC_KW
-#elif defined(MCUBOOT_ENCRYPT_EC256)
-#    define EXPECTED_ENC_TLV    IMAGE_TLV_ENC_EC256
-#    define EC_PUBK_INDEX       (0)
-#    define EC_TAG_INDEX        (65)
-#    define EC_CIPHERKEY_INDEX  (65 + 32)
-_Static_assert(EC_CIPHERKEY_INDEX + BOOT_ENC_KEY_SIZE == EXPECTED_ENC_LEN,
-        "Please fix ECIES-P256 component indexes");
-#elif defined(MCUBOOT_ENCRYPT_X25519)
-#    define EXPECTED_ENC_TLV    IMAGE_TLV_ENC_X25519
-#    define EC_PUBK_INDEX       (0)
-#    define EC_TAG_INDEX        (32)
-#    define EC_CIPHERKEY_INDEX  (32 + 32)
-_Static_assert(EC_CIPHERKEY_INDEX + BOOT_ENC_KEY_SIZE == EXPECTED_ENC_LEN,
-        "Please fix ECIES-X25519 component indexes");
-#endif
-
 #if ( (defined(MCUBOOT_ENCRYPT_RSA) && defined(MCUBOOT_USE_MBED_TLS) && !defined(MCUBOOT_USE_PSA_CRYPTO)) || \
       (defined(MCUBOOT_ENCRYPT_EC256) && defined(MCUBOOT_USE_MBED_TLS)) )
 #if MBEDTLS_VERSION_NUMBER >= 0x03000000
@@ -627,6 +599,7 @@ boot_decrypt_key(const uint8_t *buf, uint8_t *enckey)
 
     return rc;
 }
+#endif /* CONFIG_BOOT_ED25519_PSA */
 
 /*
  * Load encryption key.
@@ -681,6 +654,39 @@ boot_enc_load(struct enc_key_data *enc_state, int slot,
     return boot_decrypt_key(buf, bs->enckey[slot]);
 }
 
+int
+boot_enc_init(struct enc_key_data *enc_state, uint8_t slot)
+{
+    bootutil_aes_ctr_init(&enc_state[slot].aes_ctr);
+    return 0;
+}
+
+int
+boot_enc_drop(struct enc_key_data *enc_state, uint8_t slot)
+{
+    bootutil_aes_ctr_drop(&enc_state[slot].aes_ctr);
+    enc_state[slot].valid = 0;
+    return 0;
+}
+
+int
+boot_enc_set_key(struct enc_key_data *enc_state, uint8_t slot,
+        const struct boot_status *bs)
+{
+    int rc;
+
+    rc = bootutil_aes_ctr_set_key(&enc_state[slot].aes_ctr, bs->enckey[slot]);
+    if (rc != 0) {
+        boot_enc_drop(enc_state, slot);
+        return -1;
+    }
+
+    enc_state[slot].valid = 1;
+
+    return 0;
+}
+
+
 bool
 boot_enc_valid(struct enc_key_data *enc_state, int slot)
 {