wolfssl: Add support for ML-KEM

scripts/test.sh

@@ -54,8 +54,8 @@ build_wolfssl()
 					--enable-aesccm --enable-aesctr --enable-camellia
 					--enable-curve25519 --enable-curve448 --enable-des3
 					--enable-ecccustcurves --enable-ed25519 --enable-ed448
-					--enable-keygen --with-max-rsa-bits=8192 --enable-md4
+					--enable-keygen --enable-kyber --with-max-rsa-bits=8192
-					--enable-rsapss --enable-sha3 --enable-shake256"
+					--enable-md4 --enable-rsapss --enable-sha3 --enable-shake256"
 
 	git clone https://github.com/wolfSSL/wolfssl.git $WOLFSSL_DIR &&
 	cd $WOLFSSL_DIR &&
@@ -243,8 +243,8 @@ botan)
 	fi
 	;;
 wolfssl)
-	CONFIG="--disable-defaults --enable-pki --enable-wolfssl --enable-pem --enable-pkcs1 --enable-pkcs8 --enable-x509 --enable-constraints"
+	CONFIG="--disable-defaults --enable-pki --enable-wolfssl --enable-pem --enable-pkcs1 --enable-pkcs8 --enable-x509 --enable-constraints --enable-drbg"
-	export TESTS_PLUGINS="test-vectors wolfssl! pem pkcs1 pkcs8 x509 constraints"
+	export TESTS_PLUGINS="test-vectors wolfssl! pem pkcs1 pkcs8 x509 constraints drbg"
 	# build with custom options to enable all the features the plugin supports
 	DEPS=""
 	if test "$1" = "build-deps"; then

src/libstrongswan/plugins/wolfssl/Makefile.am

@@ -25,6 +25,7 @@ libstrongswan_wolfssl_la_SOURCES = \
 	wolfssl_hasher.h wolfssl_hasher.c \
 	wolfssl_hmac.h wolfssl_hmac.c \
 	wolfssl_kdf.h wolfssl_kdf.c \
+	wolfssl_kem.h wolfssl_kem.c \
 	wolfssl_rsa_public_key.h wolfssl_rsa_public_key.c \
 	wolfssl_rsa_private_key.h wolfssl_rsa_private_key.c \
 	wolfssl_rng.h wolfssl_rng.c \

src/libstrongswan/plugins/wolfssl/wolfssl_kem.c

@@ -0,0 +1,324 @@
+/*
+ * Copyright (C) 2024 Tobias Brunner, codelabs GmbH
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+
+#include "wolfssl_common.h"
+
+#ifdef WOLFSSL_HAVE_KYBER
+
+#include <wolfssl/wolfcrypt/kyber.h>
+#ifdef WOLFSSL_WC_KYBER
+#include <wolfssl/wolfcrypt/wc_kyber.h>
+#endif
+#if defined(HAVE_LIBOQS)
+#include <wolfssl/wolfcrypt/ext_kyber.h>
+#endif
+
+typedef struct private_key_exchange_t private_key_exchange_t;
+
+/**
+ * Private data.
+ */
+struct private_key_exchange_t {
+
+	/**
+	 * Public interface.
+	 */
+	key_exchange_t public;
+
+	/**
+	 * KE method.
+	 */
+	key_exchange_method_t method;
+
+	/**
+	 * Internal algorithm type.
+	 */
+	int type;
+
+	/**
+	 * Key pair as initiator.
+	 */
+	MlKemKey *kem;
+
+	/**
+	 * Ciphertext as responder.
+	 */
+	chunk_t ciphertext;
+
+	/**
+	 * Shared secret.
+	 */
+	chunk_t shared_secret;
+
+	/**
+	 * DRBG for testing.
+	 */
+	drbg_t *drbg;
+};
+
+/**
+ * Allocate random bytes from either the DRBG or a new WC_RNG instance to the
+ * given buffer. Make sure it has enough room.
+ */
+static bool get_random(private_key_exchange_t *this, size_t len, uint8_t *out)
+{
+	WC_RNG rng;
+
+	if (this->drbg)
+	{
+		return this->drbg->generate(this->drbg, len, out);
+	}
+	if (wc_InitRng(&rng) != 0)
+	{
+		return FALSE;
+	}
+	if (wc_RNG_GenerateBlock(&rng, out, len) != 0)
+	{
+		wc_FreeRng(&rng);
+		return FALSE;
+	}
+	wc_FreeRng(&rng);
+	return TRUE;
+}
+
+/**
+ * Generate a key pair as initiator and return the public key.
+ */
+static bool generate_keypair(private_key_exchange_t *this, chunk_t *public)
+{
+	uint8_t random[WC_ML_KEM_MAKEKEY_RAND_SZ];
+	word32 len;
+
+	if (!this->kem)
+	{
+		this->kem = malloc(sizeof(MlKemKey));
+		if (wc_MlKemKey_Init(this->kem, this->type, NULL, INVALID_DEVID) != 0)
+		{
+			free(this->kem);
+			this->kem = NULL;
+			return FALSE;
+		}
+		if (!get_random(this, sizeof(random), random) ||
+			wc_MlKemKey_MakeKeyWithRandom(this->kem, random, sizeof(random)) != 0)
+		{
+			DBG1(DBG_LIB, "%N key pair generation failed",
+				 key_exchange_method_names, this->method);
+			return FALSE;
+		}
+		memwipe(random, sizeof(random));
+	}
+
+	if (wc_MlKemKey_PublicKeySize(this->kem, &len) != 0)
+	{
+		return FALSE;
+	}
+	*public = chunk_alloc(len);
+
+	if (wc_MlKemKey_EncodePublicKey(this->kem, public->ptr, public->len) != 0)
+	{
+		DBG1(DBG_LIB, "%N public key encoding failed",
+				 key_exchange_method_names, this->method);
+		chunk_free(public);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+METHOD(key_exchange_t, get_public_key, bool,
+	private_key_exchange_t *this, chunk_t *value)
+{
+	/* as responder, this method is called after set_public_key(), which
+	 * encapsulated the secret to produce this ciphertext */
+	if (this->ciphertext.len)
+	{
+		*value = chunk_clone(this->ciphertext);
+		return TRUE;
+	}
+
+	/* as initiator, we generate a key pair and return the public key */
+	return generate_keypair(this, value);
+}
+
+/**
+ * Decapsulate the shared secret from the given ciphertext using our key pair.
+ */
+static bool decaps_ciphertext(private_key_exchange_t *this, chunk_t ciphertext)
+{
+	word32 ss_len;
+
+	if (wc_MlKemKey_SharedSecretSize(this->kem, &ss_len) != 0)
+	{
+		return FALSE;
+	}
+	this->shared_secret = chunk_alloc(ss_len);
+
+	/* FIXME: can't use the wc_MlKemKey alias here as it's incorrectly mapped
+	 * to wc_KyberKey_Encapsulate */
+	if (wc_KyberKey_Decapsulate(this->kem, this->shared_secret.ptr,
+								ciphertext.ptr, ciphertext.len) != 0)
+	{
+		DBG1(DBG_LIB, "%N decapsulation failed",
+			 key_exchange_method_names, this->method);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+/**
+ * Generate a shared secret an encapsulate it using the given public key.
+ */
+static bool encaps_shared_secret(private_key_exchange_t *this, chunk_t public)
+{
+	uint8_t random[WC_ML_KEM_ENC_RAND_SZ];
+	MlKemKey kem;
+	word32 ct_len, ss_len;
+
+	if (wc_MlKemKey_Init(&kem, this->type, NULL, INVALID_DEVID) != 0)
+	{
+		return FALSE;
+	}
+	if (wc_MlKemKey_DecodePublicKey(&kem, public.ptr, public.len) != 0)
+	{
+		DBG1(DBG_LIB, "%N public key invalid",
+			 key_exchange_method_names, this->method);
+		wc_MlKemKey_Free(&kem);
+		return FALSE;
+	}
+
+	if (wc_MlKemKey_CipherTextSize(&kem, &ct_len) != 0 ||
+		wc_MlKemKey_SharedSecretSize(&kem, &ss_len) != 0)
+	{
+		wc_MlKemKey_Free(&kem);
+		return FALSE;
+	}
+	this->ciphertext = chunk_alloc(ct_len);
+	this->shared_secret = chunk_alloc(ss_len);
+
+	if (!get_random(this, sizeof(random), random) ||
+		wc_MlKemKey_EncapsulateWithRandom(&kem, this->ciphertext.ptr,
+						this->shared_secret.ptr, random, sizeof(random)) != 0)
+	{
+		DBG1(DBG_LIB, "%N encapsulation failed",
+			 key_exchange_method_names, this->method);
+		wc_MlKemKey_Free(&kem);
+		return FALSE;
+	}
+	memwipe(random, sizeof(random));
+	wc_MlKemKey_Free(&kem);
+	return TRUE;
+}
+
+METHOD(key_exchange_t, set_public_key, bool,
+	private_key_exchange_t *this, chunk_t value)
+{
+	/* as initiator, we decapsulate the secret from the given ciphertext */
+	if (this->kem)
+	{
+		return decaps_ciphertext(this, value);
+	}
+
+	/* as responder, we generate a secret and encapsulate it */
+	return encaps_shared_secret(this, value);
+}
+
+METHOD(key_exchange_t, get_shared_secret, bool,
+	private_key_exchange_t *this, chunk_t *secret)
+{
+	*secret = chunk_clone(this->shared_secret);
+	return TRUE;
+}
+
+METHOD(key_exchange_t, get_method, key_exchange_method_t,
+	private_key_exchange_t *this)
+{
+	return this->method;
+}
+
+METHOD(key_exchange_t, set_seed, bool,
+	private_key_exchange_t *this, chunk_t value, drbg_t *drbg)
+{
+	if (!drbg)
+	{
+		return FALSE;
+	}
+	DESTROY_IF(this->drbg);
+	this->drbg = drbg->get_ref(drbg);
+	return TRUE;
+}
+
+METHOD(key_exchange_t, destroy, void,
+	private_key_exchange_t *this)
+{
+	chunk_clear(&this->shared_secret);
+	chunk_free(&this->ciphertext);
+	wc_MlKemKey_Free(this->kem);
+	free(this->kem);
+	DESTROY_IF(this->drbg);
+	free(this);
+}
+
+/*
+ * Described in header
+ */
+key_exchange_t *wolfssl_kem_create(key_exchange_method_t method)
+{
+	private_key_exchange_t *this;
+	int type;
+
+	switch (method)
+	{
+#ifdef WOLFSSL_KYBER512
+		case ML_KEM_512:
+			type = WC_ML_KEM_512;
+			break;
+#endif
+#ifdef WOLFSSL_KYBER768
+		case ML_KEM_768:
+			type = WC_ML_KEM_768;
+			break;
+#endif
+#ifdef WOLFSSL_KYBER1024
+		case ML_KEM_1024:
+			type = WC_ML_KEM_1024;
+			break;
+#endif
+		default:
+			return NULL;
+	}
+
+	INIT(this,
+		.public = {
+			.get_method = _get_method,
+			.get_public_key = _get_public_key,
+			.set_public_key = _set_public_key,
+			.get_shared_secret = _get_shared_secret,
+			.set_seed = _set_seed,
+			.destroy = _destroy,
+		},
+		.method = method,
+		.type = type,
+	);
+	return &this->public;
+}
+
+#endif /* WOLFSSL_HAVE_KYBER */

src/libstrongswan/plugins/wolfssl/wolfssl_kem.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2024 Tobias Brunner, codelabs GmbH
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/**
+ * Implements key encapsulation methods (KEM) using wolfSSL.
+ *
+ * @defgroup wolfssl_kem wolfssl_kem
+ * @{ @ingroup wolfssl_p
+ */
+
+#ifndef WOLFSSL_KEM_H_
+#define WOLFSSL_KEM_H_
+
+#include <crypto/key_exchange.h>
+
+/**
+ * Creates a new key_exchange_t object.
+ *
+ * @param method	KEM to instantiate
+ * @return			key_exchange_t object, NULL if not supported
+ */
+key_exchange_t *wolfssl_kem_create(key_exchange_method_t method);
+
+#endif /** WOLFSSL_KEM_H_ @}*/

src/libstrongswan/plugins/wolfssl/wolfssl_plugin.c

@@ -1,6 +1,7 @@
 /*
- * Copyright (C) 2019 Sean Parkinson, wolfSSL Inc.
  * Copyright (C) 2021 Andreas Steffen, strongSec GmbH
+ * Copyright (C) 2019-2024 Tobias Brunner, codelabs GmbH
+ * Copyright (C) 2019 Sean Parkinson, wolfSSL Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -38,6 +39,7 @@
 #include "wolfssl_hasher.h"
 #include "wolfssl_hmac.h"
 #include "wolfssl_kdf.h"
+#include "wolfssl_kem.h"
 #include "wolfssl_rsa_private_key.h"
 #include "wolfssl_rsa_public_key.h"
 #include "wolfssl_rng.h"
@@ -459,6 +461,12 @@ METHOD(plugin_t, get_features, int,
 		#endif
 	#endif /* HAVE_ECC_VERIFY */
 #endif /* HAVE_ECC */
+#ifdef WOLFSSL_HAVE_KYBER
+		PLUGIN_REGISTER(KE, wolfssl_kem_create),
+			PLUGIN_PROVIDE(KE, ML_KEM_512),
+			PLUGIN_PROVIDE(KE, ML_KEM_768),
+			PLUGIN_PROVIDE(KE, ML_KEM_1024),
+#endif
 #if defined (HAVE_CURVE25519) || defined(HAVE_CURVE448)
 		PLUGIN_REGISTER(KE, wolfssl_x_diffie_hellman_create),
 	#ifdef HAVE_CURVE25519

testing/scripts/recipes/012_wolfssl.mk

@@ -26,6 +26,7 @@ CONFIG_OPTS = \
 	--enable-ed25519 \
 	--enable-ed448 \
 	--enable-keygen \
+	--enable-kyber \
 	--enable-md4 \
 	--enable-rsapss \
 	--enable-sha3 \

testing/tests/wolfssl/rw-cert/hosts/moon/etc/strongswan.conf

@@ -5,7 +5,7 @@ swanctl {
 }
 
 charon-systemd {
-  load = nonce test-vectors pem wolfssl x509 revocation constraints pkcs1 pubkey curl kernel-netlink socket-default updown vici
+  load = nonce test-vectors drbg pem wolfssl x509 revocation constraints pkcs1 pubkey curl kernel-netlink socket-default updown vici
 
   rsa_pss = yes
   integrity_test = yes