wolfssl: Add support for x448 Diffie-Hellman

src/libstrongswan/plugins/wolfssl/wolfssl_plugin.c

@@ -377,10 +377,15 @@ METHOD(plugin_t, get_features, int,
 		#endif
 	#endif /* HAVE_ECC_VERIFY */
 #endif /* HAVE_ECC */
-#ifdef HAVE_CURVE25519
+#if defined (HAVE_CURVE25519) || defined(HAVE_CURVE448)
 		PLUGIN_REGISTER(DH, wolfssl_x_diffie_hellman_create),
+	#ifdef HAVE_CURVE25519
 			PLUGIN_PROVIDE(DH, CURVE_25519),
-#endif
+	#endif
+	#ifdef HAVE_CURVE448
+			PLUGIN_PROVIDE(DH, CURVE_448),
+	#endif
+#endif /* HAVE_CURVE25519 || HAVE_CURVE448 */
 #ifdef HAVE_ED25519
 		/* EdDSA private/public key loading */
 		PLUGIN_REGISTER(PUBKEY, wolfssl_ed_public_key_load, TRUE),

src/libstrongswan/plugins/wolfssl/wolfssl_x_diffie_hellman.c

@@ -1,4 +1,7 @@
 /*
+ * Copyright (C) 2020 Tobias Brunner
+ * HSR Hochschule fuer Technik Rapperswil
+ *
  * Copyright (C) 2019 Sean Parkinson, wolfSSL Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -22,13 +25,19 @@
 
 #include "wolfssl_common.h"
 
-#ifdef HAVE_CURVE25519
+#if defined(HAVE_CURVE25519) || defined(HAVE_CURVE448)
 
 #include "wolfssl_x_diffie_hellman.h"
 
 #include <utils/debug.h>
 
+#ifdef HAVE_CURVE25519
 #include <wolfssl/wolfcrypt/curve25519.h>
+#endif
+#ifdef HAVE_CURVE448
+#include <wolfssl/wolfcrypt/curve448.h>
+#endif
+
 #include <wolfssl/wolfcrypt/fe_operations.h>
 
 typedef struct private_diffie_hellman_t private_diffie_hellman_t;
@@ -50,7 +59,14 @@ struct private_diffie_hellman_t {
 	/**
 	 * Private (public) key
 	 */
-	curve25519_key key;
+	union {
+#ifdef HAVE_CURVE25519
+		curve25519_key key25519;
+#endif
+#ifdef HAVE_CURVE448
+		curve448_key key448;
+#endif
+	} key;
 
 	/**
 	 * Shared secret
@@ -58,24 +74,12 @@ struct private_diffie_hellman_t {
 	chunk_t shared_secret;
 };
 
-/**
+#ifdef HAVE_CURVE25519
- * Compute the shared secret
- */
-static bool compute_shared_key(private_diffie_hellman_t *this,
-							   curve25519_key *pub, chunk_t *shared_secret)
-{
-	word32 len = CURVE25519_KEYSIZE;
-	int ret;
 
-	*shared_secret = chunk_alloc(len);
+METHOD(diffie_hellman_t, set_other_public_value_25519, bool,
-	ret = wc_curve25519_shared_secret_ex(&this->key, pub, shared_secret->ptr,
-										 &len, EC25519_LITTLE_ENDIAN);
-	return ret == 0;
-}
-
-METHOD(diffie_hellman_t, set_other_public_value, bool,
 	private_diffie_hellman_t *this, chunk_t value)
 {
+	word32 len = CURVE25519_KEYSIZE;
 	curve25519_key pub;
 	int ret;
 
@@ -102,8 +106,9 @@ METHOD(diffie_hellman_t, set_other_public_value, bool,
 	}
 
 	chunk_clear(&this->shared_secret);
-
+	this->shared_secret = chunk_alloc(len);
-	if (!compute_shared_key(this, &pub, &this->shared_secret))
+	if (wc_curve25519_shared_secret_ex(&this->key.key25519, &pub,
+					this->shared_secret.ptr, &len, EC25519_LITTLE_ENDIAN) != 0)
 	{
 		DBG1(DBG_LIB, "%N shared secret computation failed",
 			 diffie_hellman_group_names, this->group);
@@ -115,13 +120,13 @@ METHOD(diffie_hellman_t, set_other_public_value, bool,
 	return TRUE;
 }
 
-METHOD(diffie_hellman_t, get_my_public_value, bool,
+METHOD(diffie_hellman_t, get_my_public_value_25519, bool,
 	private_diffie_hellman_t *this, chunk_t *value)
 {
 	word32 len = CURVE25519_KEYSIZE;
 
 	*value = chunk_alloc(len);
-	if (wc_curve25519_export_public_ex(&this->key, value->ptr, &len,
+	if (wc_curve25519_export_public_ex(&this->key.key25519, value->ptr, &len,
 									   EC25519_LITTLE_ENDIAN) != 0)
 	{
 		chunk_free(value);
@@ -130,7 +135,7 @@ METHOD(diffie_hellman_t, get_my_public_value, bool,
 	return TRUE;
 }
 
-METHOD(diffie_hellman_t, set_private_value, bool,
+METHOD(diffie_hellman_t, set_private_value_25519, bool,
 	private_diffie_hellman_t *this, chunk_t value)
 {
 	curve25519_key pub;
@@ -147,17 +152,112 @@ METHOD(diffie_hellman_t, set_private_value, bool,
 	}
 	if (ret == 0)
 	{
-		ret = wc_curve25519_import_private_ex(value.ptr, value.len, &this->key,
+		ret = wc_curve25519_import_private_ex(value.ptr, value.len,
-											  EC25519_LITTLE_ENDIAN);
+									&this->key.key25519, EC25519_LITTLE_ENDIAN);
 	}
 	if (ret == 0)
 	{
-		ret = wc_curve25519_shared_secret_ex(&this->key, &pub,
+		ret = wc_curve25519_shared_secret_ex(&this->key.key25519, &pub,
-								this->key.p.point, &len, EC25519_LITTLE_ENDIAN);
+											 this->key.key25519.p.point, &len,
+											 EC25519_LITTLE_ENDIAN);
 	}
 	return ret == 0;
 }
 
+#endif /* HAVE_CURVE25519 */
+
+#ifdef HAVE_CURVE448
+
+METHOD(diffie_hellman_t, set_other_public_value_448, bool,
+	private_diffie_hellman_t *this, chunk_t value)
+{
+	word32 len = CURVE448_KEY_SIZE;
+	curve448_key pub;
+	int ret;
+
+	if (!diffie_hellman_verify_value(this->group, value))
+	{
+		return FALSE;
+	}
+
+	ret = wc_curve448_init(&pub);
+	if (ret != 0)
+	{
+		DBG1(DBG_LIB, "%N public key initialization failed",
+			 diffie_hellman_group_names, this->group);
+		return FALSE;
+	}
+
+	ret = wc_curve448_import_public_ex(value.ptr, value.len, &pub,
+									   EC448_LITTLE_ENDIAN);
+	if (ret != 0)
+	{
+		DBG1(DBG_LIB, "%N public value is malformed",
+			 diffie_hellman_group_names, this->group);
+		return FALSE;
+	}
+
+	chunk_clear(&this->shared_secret);
+	this->shared_secret = chunk_alloc(len);
+	if (wc_curve448_shared_secret_ex(&this->key.key448, &pub,
+					this->shared_secret.ptr, &len, EC448_LITTLE_ENDIAN) != 0)
+	{
+		DBG1(DBG_LIB, "%N shared secret computation failed",
+			 diffie_hellman_group_names, this->group);
+		chunk_clear(&this->shared_secret);
+		wc_curve448_free(&pub);
+		return FALSE;
+	}
+	wc_curve448_free(&pub);
+	return TRUE;
+}
+
+METHOD(diffie_hellman_t, get_my_public_value_448, bool,
+	private_diffie_hellman_t *this, chunk_t *value)
+{
+	word32 len = CURVE448_KEY_SIZE;
+
+	*value = chunk_alloc(len);
+	if (wc_curve448_export_public_ex(&this->key.key448, value->ptr, &len,
+									 EC448_LITTLE_ENDIAN) != 0)
+	{
+		chunk_free(value);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+METHOD(diffie_hellman_t, set_private_value_448, bool,
+	private_diffie_hellman_t *this, chunk_t value)
+{
+	curve448_key pub;
+	u_char basepoint[CURVE448_KEY_SIZE] = {5};
+	word32 len = CURVE448_KEY_SIZE;
+	int ret;
+
+	ret = wc_curve448_init(&pub);
+	/* create base point for calculating public key */
+	if (ret == 0)
+	{
+		ret = wc_curve448_import_public_ex(basepoint, CURVE448_KEY_SIZE,
+										   &pub, EC448_LITTLE_ENDIAN);
+	}
+	if (ret == 0)
+	{
+		ret = wc_curve448_import_private_ex(value.ptr, value.len,
+										&this->key.key448, EC448_LITTLE_ENDIAN);
+	}
+	if (ret == 0)
+	{
+		ret = wc_curve448_shared_secret_ex(&this->key.key448, &pub,
+										   this->key.key448.p, &len,
+										   EC448_LITTLE_ENDIAN);
+	}
+	return ret == 0;
+}
+
+#endif /* HAVE_CURVE448 */
+
 METHOD(diffie_hellman_t, get_shared_secret, bool,
 	private_diffie_hellman_t *this, chunk_t *secret)
 {
@@ -178,7 +278,18 @@ METHOD(diffie_hellman_t, get_dh_group, diffie_hellman_group_t,
 METHOD(diffie_hellman_t, destroy, void,
 	private_diffie_hellman_t *this)
 {
-	wc_curve25519_free(&this->key);
+	if (this->group == CURVE_25519)
+	{
+#ifdef HAVE_CURVE25519
+		wc_curve25519_free(&this->key.key25519);
+#endif
+	}
+	else if (this->group == CURVE_448)
+	{
+#ifdef HAVE_CURVE448
+		wc_curve448_free(&this->key.key448);
+#endif
+	}
 	chunk_clear(&this->shared_secret);
 	free(this);
 }
@@ -190,34 +301,57 @@ diffie_hellman_t *wolfssl_x_diffie_hellman_create(diffie_hellman_group_t group)
 {
 	private_diffie_hellman_t *this;
 	WC_RNG rng;
-	int ret;
+	int ret = -1;
 
 	INIT(this,
 		.public = {
 			.get_shared_secret = _get_shared_secret,
-			.set_other_public_value = _set_other_public_value,
-			.get_my_public_value = _get_my_public_value,
-			.set_private_value = _set_private_value,
 			.get_dh_group = _get_dh_group,
 			.destroy = _destroy,
 		},
 		.group = group,
 	);
 
-	if (wc_curve25519_init(&this->key) != 0)
-	{
-		DBG1(DBG_LIB, "initializing key failed");
-		free(this);
-		return NULL;
-	}
-
 	if (wc_InitRng(&rng) != 0)
 	{
 		DBG1(DBG_LIB, "initializing a random number generator failed");
 		destroy(this);
 		return NULL;
 	}
-	ret = wc_curve25519_make_key(&rng, CURVE25519_KEYSIZE, &this->key);
+
+	if (group == CURVE_25519)
+	{
+#ifdef HAVE_CURVE25519
+		this->public.set_other_public_value = _set_other_public_value_25519;
+		this->public.get_my_public_value = _get_my_public_value_25519;
+		this->public.set_private_value = _set_private_value_25519;
+
+		if (wc_curve25519_init(&this->key.key25519) != 0)
+		{
+			DBG1(DBG_LIB, "initializing key failed");
+			free(this);
+			return NULL;
+		}
+		ret = wc_curve25519_make_key(&rng, CURVE25519_KEYSIZE,
+									 &this->key.key25519);
+#endif
+	}
+	else if (group == CURVE_448)
+	{
+#ifdef HAVE_CURVE448
+		this->public.set_other_public_value = _set_other_public_value_448;
+		this->public.get_my_public_value = _get_my_public_value_448;
+		this->public.set_private_value = _set_private_value_448;
+
+		if (wc_curve448_init(&this->key.key448) != 0)
+		{
+			DBG1(DBG_LIB, "initializing key failed");
+			free(this);
+			return NULL;
+		}
+		ret = wc_curve448_make_key(&rng, CURVE448_KEY_SIZE, &this->key.key448);
+#endif
+	}
 	wc_FreeRng(&rng);
 	if (ret != 0)
 	{
@@ -228,4 +362,4 @@ diffie_hellman_t *wolfssl_x_diffie_hellman_create(diffie_hellman_group_t group)
 	return &this->public;
 }
 
-#endif /* HAVE_CURVE25519 */
+#endif /* HAVE_CURVE25519 || HAVE_CURVE448 */

src/libstrongswan/plugins/wolfssl/wolfssl_x_diffie_hellman.h

@@ -21,7 +21,7 @@
  */
 
 /**
- * Implementation of the X25519 Diffie-Hellman algorithm using wolfSSL.
+ * Implementation of the X25519/X448 Diffie-Hellman algorithm using wolfSSL.
  *
  * @defgroup wolfssl_x_diffie_hellman wolfssl_x_diffie_hellman
  * @{ @ingroup wolfssl_p