pkcs11: Added support for ECDH.

src/libstrongswan/plugins/pkcs11/Makefile.am

@@ -18,6 +18,7 @@ libstrongswan_pkcs11_la_SOURCES = \
 	pkcs11_hasher.h pkcs11_hasher.c \
 	pkcs11_rng.h pkcs11_rng.c \
 	pkcs11_dh.h pkcs11_dh.c \
+	pkcs11_ec_dh.h pkcs11_ec_dh.c \
 	pkcs11_manager.h pkcs11_manager.c
 
 libstrongswan_pkcs11_la_LDFLAGS = -module -avoid-version

src/libstrongswan/plugins/pkcs11/pkcs11_ec_dh.c

@@ -0,0 +1,356 @@
+/*
+ * Copyright (C) 2011 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "pkcs11_ec_dh.h"
+
+#include <debug.h>
+#include <library.h>
+#include <chunk.h>
+#include <asn1/asn1.h>
+#include <asn1/oid.h>
+
+#include "pkcs11_manager.h"
+
+typedef struct private_pkcs11_ec_dh_t private_pkcs11_ec_dh_t;
+
+/**
+ * Private data of an pkcs11_ec_dh_t object.
+ */
+struct private_pkcs11_ec_dh_t {
+
+	/**
+	 * Public pkcs11_ec_dh_t interface
+	 */
+	pkcs11_ec_dh_t public;
+
+	/**
+	 * PKCS#11 library
+	 */
+	pkcs11_library_t *lib;
+
+	/**
+	 * Session handle for this objct
+	 */
+	CK_SESSION_HANDLE session;
+
+	/**
+	 * Diffie Hellman group number.
+	 */
+	u_int16_t group;
+
+	/**
+	 * EC params (DER-encoded ANSI x9.62 Parameters value)
+	 */
+	chunk_t ecparams;
+
+	/**
+	 * Handle for own private value
+	 */
+	CK_OBJECT_HANDLE pri_key;
+
+	/**
+	 * Own public value
+	 */
+	chunk_t pub_key;
+
+	/**
+	 * Shared secret
+	 */
+	chunk_t secret;
+
+};
+
+/**
+ * Retrieve a CKA_EC_POINT from a CK_OBJECT_HANDLE, memory gets allocated
+ *
+ * The point is returned uncompressed (i.e. x-coordinate followed by the
+ * y-coordinate) without indication that this is the case (usually 0x04).
+ */
+static bool get_cka_ec_point(private_pkcs11_ec_dh_t *this, CK_OBJECT_HANDLE obj,
+							 chunk_t *value)
+{
+	CK_ATTRIBUTE attr = { CKA_EC_POINT, NULL, 0 };
+	CK_RV rv;
+	rv = this->lib->f->C_GetAttributeValue(this->session, obj, &attr, 1);
+	if (rv != CKR_OK)
+	{
+		DBG1(DBG_CFG, "C_GetAttributeValue(NULL) error: %N", ck_rv_names, rv);
+		return FALSE;
+	}
+	*value = chunk_alloc(attr.ulValueLen);
+	attr.pValue = value->ptr;
+	rv = this->lib->f->C_GetAttributeValue(this->session, obj, &attr, 1);
+	if (rv != CKR_OK)
+	{
+		DBG1(DBG_CFG, "C_GetAttributeValue() error: %N", ck_rv_names, rv);
+		chunk_free(value);
+		return FALSE;
+	}
+	if ((*value).len <= 0 || (*value).ptr[0] != 0x04)
+	{	/* we currently only support uncompressed points */
+		chunk_clear(value);
+		return FALSE;
+	}
+	*value = chunk_skip(*value, 1);
+	return TRUE;
+}
+
+/**
+ * Retrieve a CKA_VALUE from a CK_OBJECT_HANDLE, memory gets allocated
+ */
+static bool get_cka_value(private_pkcs11_ec_dh_t *this, CK_OBJECT_HANDLE obj,
+						  chunk_t *value)
+{
+	CK_ATTRIBUTE attr = { CKA_VALUE, NULL, 0 };
+	CK_RV rv;
+	rv = this->lib->f->C_GetAttributeValue(this->session, obj, &attr, 1);
+	if (rv != CKR_OK)
+	{
+		DBG1(DBG_CFG, "C_GetAttributeValue(NULL) error: %N", ck_rv_names, rv);
+		return FALSE;
+	}
+	*value = chunk_alloc(attr.ulValueLen);
+	attr.pValue = value->ptr;
+	rv = this->lib->f->C_GetAttributeValue(this->session, obj, &attr, 1);
+	if (rv != CKR_OK)
+	{
+		DBG1(DBG_CFG, "C_GetAttributeValue() error: %N", ck_rv_names, rv);
+		chunk_free(value);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+METHOD(diffie_hellman_t, set_other_public_value, void,
+	private_pkcs11_ec_dh_t *this, chunk_t value)
+{
+	chunk_t pubkey = chunk_alloca(value.len + 1);
+	CK_OBJECT_CLASS klass = CKO_SECRET_KEY;
+	CK_KEY_TYPE type = CKK_GENERIC_SECRET;
+	CK_ATTRIBUTE attr[] = {
+		{ CKA_CLASS, &klass, sizeof(klass) },
+		{ CKA_KEY_TYPE, &type, sizeof(type) },
+	};
+	CK_ECDH1_DERIVE_PARAMS params = {
+		CKD_NULL,
+		0,
+		NULL,
+		pubkey.len,
+		pubkey.ptr,
+	};
+	CK_MECHANISM mech = {
+		CKM_ECDH1_DERIVE,
+		&params,
+		sizeof(params),
+	};
+	CK_OBJECT_HANDLE secret;
+	CK_RV rv;
+
+	if (!lib->settings->get_bool(lib->settings,
+				"libstrongswan.ecp_x_coordinate_only", TRUE))
+	{	/* we only get the x coordinate back */
+		return;
+	}
+
+	/* we expect the public value to just be the concatenated x and y
+	 * coordinates, so we have to specify that it is an uncompressed ECPoint */
+	pubkey.ptr[0] = 0x04;
+	memcpy(pubkey.ptr + 1, value.ptr, value.len);
+
+	rv = this->lib->f->C_DeriveKey(this->session, &mech, this->pri_key,
+								   attr, countof(attr), &secret);
+	if (rv != CKR_OK)
+	{
+		DBG1(DBG_CFG, "C_DeriveKey() error: %N", ck_rv_names, rv);
+		return;
+	}
+	if (!get_cka_value(this, secret, &this->secret))
+	{
+		return;
+	}
+}
+
+METHOD(diffie_hellman_t, get_my_public_value, void,
+	private_pkcs11_ec_dh_t *this, chunk_t *value)
+{
+	*value = chunk_clone(this->pub_key);
+}
+
+METHOD(diffie_hellman_t, get_shared_secret, status_t,
+	private_pkcs11_ec_dh_t *this, chunk_t *secret)
+{
+	if (!this->secret.ptr)
+	{
+		return FAILED;
+	}
+	*secret = chunk_clone(this->secret);
+	return SUCCESS;
+}
+
+METHOD(diffie_hellman_t, get_dh_group, diffie_hellman_group_t,
+	private_pkcs11_ec_dh_t *this)
+{
+	return this->group;
+}
+
+METHOD(diffie_hellman_t, destroy, void,
+	private_pkcs11_ec_dh_t *this)
+{
+	this->lib->f->C_CloseSession(this->session);
+	chunk_clear(&this->pub_key);
+	chunk_clear(&this->secret);
+	free(this);
+}
+
+/**
+ * Generate ECDH key pair
+ */
+static bool generate_key_pair(private_pkcs11_ec_dh_t *this)
+{
+	CK_ATTRIBUTE pub_attr[] = {
+		{ CKA_EC_PARAMS, this->ecparams.ptr, this->ecparams.len },
+	};
+	CK_MECHANISM mech = {
+		CKM_EC_KEY_PAIR_GEN,
+		NULL,
+		0,
+	};
+	CK_OBJECT_HANDLE pub_key;
+	CK_RV rv;
+
+	rv = this->lib->f->C_GenerateKeyPair(this->session, &mech, pub_attr,
+							countof(pub_attr), NULL, 0, &pub_key,
+							&this->pri_key);
+	if (rv != CKR_OK)
+	{
+		DBG1(DBG_CFG, "C_GenerateKeyPair() error: %N", ck_rv_names, rv);
+		return FALSE;
+	}
+
+	if (!get_cka_ec_point(this, pub_key, &this->pub_key))
+	{
+		return FALSE;
+	}
+	return TRUE;
+}
+
+/**
+ * Find a token we can use for DH algorithm
+ */
+static pkcs11_library_t *find_token(CK_SESSION_HANDLE *session)
+{
+	enumerator_t *tokens, *mechs;
+	pkcs11_manager_t *manager;
+	pkcs11_library_t *current, *found = NULL;
+	CK_MECHANISM_TYPE type;
+	CK_SLOT_ID slot;
+
+	manager = lib->get(lib, "pkcs11-manager");
+	if (!manager)
+	{
+		return NULL;
+	}
+	tokens = manager->create_token_enumerator(manager);
+	while (tokens->enumerate(tokens, &current, &slot))
+	{
+		mechs = current->create_mechanism_enumerator(current, slot);
+		while (mechs->enumerate(mechs, &type, NULL))
+		{
+			/* we assume CKM_EC_KEY_PAIR_GEN is supported too */
+			if (type == CKM_ECDH1_DERIVE)
+			{
+				if (current->f->C_OpenSession(slot, CKF_SERIAL_SESSION,
+											  NULL, NULL, session) == CKR_OK)
+				{
+					found = current;
+					break;
+				}
+			}
+		}
+		mechs->destroy(mechs);
+		if (found)
+		{
+			break;
+		}
+	}
+	tokens->destroy(tokens);
+	return found;
+}
+
+/**
+ * Lookup the EC params matching the given group
+ */
+static chunk_t lookup_ecparams(diffie_hellman_group_t group)
+{
+	switch (group)
+	{
+		case ECP_192_BIT:
+			return asn1_build_known_oid(OID_PRIME192V1);
+		case ECP_224_BIT:
+			return asn1_build_known_oid(OID_SECT224R1);
+		case ECP_256_BIT:
+			return asn1_build_known_oid(OID_PRIME256V1);
+		case ECP_384_BIT:
+			return asn1_build_known_oid(OID_SECT384R1);
+		case ECP_521_BIT:
+			return asn1_build_known_oid(OID_SECT521R1);
+		default:
+			break;
+	}
+	return chunk_empty;
+}
+
+/*
+ * Described in header.
+ */
+pkcs11_ec_dh_t *pkcs11_ec_dh_create(diffie_hellman_group_t group)
+{
+	private_pkcs11_ec_dh_t *this;
+
+	INIT(this,
+		.public = {
+			.dh = {
+				.get_shared_secret = _get_shared_secret,
+				.set_other_public_value = _set_other_public_value,
+				.get_my_public_value = _get_my_public_value,
+				.get_dh_group = _get_dh_group,
+				.destroy = _destroy,
+			},
+		},
+		.group = group,
+	);
+
+	this->ecparams = lookup_ecparams(group);
+	if (!this->ecparams.ptr)
+	{
+		free(this);
+		return NULL;
+	}
+
+	this->lib = find_token(&this->session);
+	if (!this->lib)
+	{
+		free(this);
+		return NULL;
+	}
+
+	if (!generate_key_pair(this))
+	{
+		free(this);
+		return NULL;
+	}
+	return &this->public;
+}
+

src/libstrongswan/plugins/pkcs11/pkcs11_ec_dh.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2011 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup pkcs11_ec_dh pkcs11_ec_dh
+ * @{ @ingroup pkcs11_p
+ */
+
+#ifndef PKCS11_EC_DH_H_
+#define PKCS11_EC_DH_H_
+
+typedef struct pkcs11_ec_dh_t pkcs11_ec_dh_t;
+
+#include <library.h>
+
+/**
+ * Implementation of the EC Diffie-Hellman algorithm via PKCS#11.
+ */
+struct pkcs11_ec_dh_t {
+
+	/**
+	 * Implements diffie_hellman_t interface.
+	 */
+	diffie_hellman_t dh;
+};
+
+/**
+ * Creates a new pkcs11_ec_dh_t object.
+ *
+ * @param group			EC Diffie Hellman group number to use
+ * @return				pkcs11_ec_dh_t object, NULL if not supported
+ */
+pkcs11_ec_dh_t *pkcs11_ec_dh_create(diffie_hellman_group_t group);
+
+#endif /** PKCS11_EC_DH_H_ @}*/
+

src/libstrongswan/plugins/pkcs11/pkcs11_plugin.c

@@ -30,6 +30,7 @@
 #include "pkcs11_hasher.h"
 #include "pkcs11_rng.h"
 #include "pkcs11_dh.h"
+#include "pkcs11_ec_dh.h"
 
 typedef struct private_pkcs11_plugin_t private_pkcs11_plugin_t;
 
@@ -163,12 +164,23 @@ METHOD(plugin_t, get_features, int,
 		PLUGIN_REGISTER(PUBKEY, pkcs11_public_key_load, TRUE),
 			PLUGIN_PROVIDE(PUBKEY, KEY_RSA),
 	};
+	static plugin_feature_t f_ecdh[] = {
+		PLUGIN_REGISTER(DH, pkcs11_ec_dh_create),
+			PLUGIN_PROVIDE(DH, ECP_192_BIT),
+			PLUGIN_PROVIDE(DH, ECP_224_BIT),
+			PLUGIN_PROVIDE(DH, ECP_256_BIT),
+			PLUGIN_PROVIDE(DH, ECP_384_BIT),
+			PLUGIN_PROVIDE(DH, ECP_521_BIT),
+	};
 	static plugin_feature_t f[countof(f_hash) + countof(f_dh) + countof(f_rng) +
-							  countof(f_key)] = {};
+							  countof(f_key) + countof(f_ecdh)] = {};
 	static int count = 0;
 
 	if (!count)
 	{	/* initialize only once */
+		bool use_ecc = lib->settings->get_bool(lib->settings,
+							"libstrongswan.plugins.pkcs11.use_ecc", FALSE);
+
 		add_features(f, f_key, countof(f_key), &count);
 		if (lib->settings->get_bool(lib->settings,
 							"libstrongswan.plugins.pkcs11.use_hasher", FALSE))
@@ -184,6 +196,10 @@ METHOD(plugin_t, get_features, int,
 							"libstrongswan.plugins.pkcs11.use_dh", FALSE))
 		{
 			add_features(f, f_dh, countof(f_dh), &count);
+			if (use_ecc)
+			{
+				add_features(f, f_ecdh, countof(f_ecdh), &count);
+			}
 		}
 	}
 	*features = f;