1 files changed, 588 insertions, 0 deletions

diff --git a/src/libcharon/sa/ikev2/keymat_v2.c b/src/libcharon/sa/ikev2/keymat_v2.c
new file mode 100644
index 000000000..3adceeec4
--- /dev/null
+++ b/src/libcharon/sa/ikev2/keymat_v2.c
@@ -0,0 +1,588 @@
+/*
+ * Copyright (C) 2008 Martin Willi
+ * 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 "keymat_v2.h"
+
+#include <daemon.h>
+#include <crypto/prf_plus.h>
+
+typedef struct private_keymat_v2_t private_keymat_v2_t;
+
+/**
+ * Private data of an keymat_t object.
+ */
+struct private_keymat_v2_t {
+
+	/**
+	 * Public keymat_v2_t interface.
+	 */
+	keymat_v2_t public;
+
+	/**
+	 * IKE_SA Role, initiator or responder
+	 */
+	bool initiator;
+
+	/**
+	 * inbound AEAD
+	 */
+	aead_t *aead_in;
+
+	/**
+	 * outbound AEAD
+	 */
+	aead_t *aead_out;
+
+	/**
+	 * General purpose PRF
+	 */
+	prf_t *prf;
+
+	/**
+	 * Negotiated PRF algorithm
+	 */
+	pseudo_random_function_t prf_alg;
+
+	/**
+	 * Key to derive key material from for CHILD_SAs, rekeying
+	 */
+	chunk_t skd;
+
+	/**
+	 * Key to build outging authentication data (SKp)
+	 */
+	chunk_t skp_build;
+
+	/**
+	 * Key to verify incoming authentication data (SKp)
+	 */
+	chunk_t skp_verify;
+};
+
+METHOD(keymat_t, get_version, ike_version_t,
+	private_keymat_v2_t *this)
+{
+	return IKEV2;
+}
+
+METHOD(keymat_t, create_dh, diffie_hellman_t*,
+	private_keymat_v2_t *this, diffie_hellman_group_t group)
+{
+	return lib->crypto->create_dh(lib->crypto, group);
+}
+
+/**
+ * Derive IKE keys for a combined AEAD algorithm
+ */
+static bool derive_ike_aead(private_keymat_v2_t *this, u_int16_t alg,
+							u_int16_t key_size, prf_plus_t *prf_plus)
+{
+	aead_t *aead_i, *aead_r;
+	chunk_t key;
+
+	/* SK_ei/SK_er used for encryption */
+	aead_i = lib->crypto->create_aead(lib->crypto, alg, key_size / 8);
+	aead_r = lib->crypto->create_aead(lib->crypto, alg, key_size / 8);
+	if (aead_i == NULL || aead_r == NULL)
+	{
+		DBG1(DBG_IKE, "%N %N (key size %d) not supported!",
+			 transform_type_names, ENCRYPTION_ALGORITHM,
+			 encryption_algorithm_names, alg, key_size);
+		return FALSE;
+	}
+	key_size = aead_i->get_key_size(aead_i);
+
+	prf_plus->allocate_bytes(prf_plus, key_size, &key);
+	DBG4(DBG_IKE, "Sk_ei secret %B", &key);
+	aead_i->set_key(aead_i, key);
+	chunk_clear(&key);
+
+	prf_plus->allocate_bytes(prf_plus, key_size, &key);
+	DBG4(DBG_IKE, "Sk_er secret %B", &key);
+	aead_r->set_key(aead_r, key);
+	chunk_clear(&key);
+
+	if (this->initiator)
+	{
+		this->aead_in = aead_r;
+		this->aead_out = aead_i;
+	}
+	else
+	{
+		this->aead_in = aead_i;
+		this->aead_out = aead_r;
+	}
+	return TRUE;
+}
+
+/**
+ * Derive IKE keys for traditional encryption and MAC algorithms
+ */
+static bool derive_ike_traditional(private_keymat_v2_t *this, u_int16_t enc_alg,
+					u_int16_t enc_size, u_int16_t int_alg, prf_plus_t *prf_plus)
+{
+	crypter_t *crypter_i, *crypter_r;
+	signer_t *signer_i, *signer_r;
+	size_t key_size;
+	chunk_t key;
+
+	/* SK_ai/SK_ar used for integrity protection */
+	signer_i = lib->crypto->create_signer(lib->crypto, int_alg);
+	signer_r = lib->crypto->create_signer(lib->crypto, int_alg);
+	if (signer_i == NULL || signer_r == NULL)
+	{
+		DBG1(DBG_IKE, "%N %N not supported!",
+			 transform_type_names, INTEGRITY_ALGORITHM,
+			 integrity_algorithm_names, int_alg);
+		return FALSE;
+	}
+	key_size = signer_i->get_key_size(signer_i);
+
+	prf_plus->allocate_bytes(prf_plus, key_size, &key);
+	DBG4(DBG_IKE, "Sk_ai secret %B", &key);
+	signer_i->set_key(signer_i, key);
+	chunk_clear(&key);
+
+	prf_plus->allocate_bytes(prf_plus, key_size, &key);
+	DBG4(DBG_IKE, "Sk_ar secret %B", &key);
+	signer_r->set_key(signer_r, key);
+	chunk_clear(&key);
+
+	/* SK_ei/SK_er used for encryption */
+	crypter_i = lib->crypto->create_crypter(lib->crypto, enc_alg, enc_size / 8);
+	crypter_r = lib->crypto->create_crypter(lib->crypto, enc_alg, enc_size / 8);
+	if (crypter_i == NULL || crypter_r == NULL)
+	{
+		DBG1(DBG_IKE, "%N %N (key size %d) not supported!",
+			 transform_type_names, ENCRYPTION_ALGORITHM,
+			 encryption_algorithm_names, enc_alg, enc_size);
+		signer_i->destroy(signer_i);
+		signer_r->destroy(signer_r);
+		return FALSE;
+	}
+	key_size = crypter_i->get_key_size(crypter_i);
+
+	prf_plus->allocate_bytes(prf_plus, key_size, &key);
+	DBG4(DBG_IKE, "Sk_ei secret %B", &key);
+	crypter_i->set_key(crypter_i, key);
+	chunk_clear(&key);
+
+	prf_plus->allocate_bytes(prf_plus, key_size, &key);
+	DBG4(DBG_IKE, "Sk_er secret %B", &key);
+	crypter_r->set_key(crypter_r, key);
+	chunk_clear(&key);
+
+	if (this->initiator)
+	{
+		this->aead_in = aead_create(crypter_r, signer_r);
+		this->aead_out = aead_create(crypter_i, signer_i);
+	}
+	else
+	{
+		this->aead_in = aead_create(crypter_i, signer_i);
+		this->aead_out = aead_create(crypter_r, signer_r);
+	}
+	return TRUE;
+}
+
+METHOD(keymat_v2_t, derive_ike_keys, bool,
+	private_keymat_v2_t *this, proposal_t *proposal, diffie_hellman_t *dh,
+	chunk_t nonce_i, chunk_t nonce_r, ike_sa_id_t *id,
+	pseudo_random_function_t rekey_function, chunk_t rekey_skd)
+{
+	chunk_t skeyseed, key, secret, full_nonce, fixed_nonce, prf_plus_seed;
+	chunk_t spi_i, spi_r;
+	prf_plus_t *prf_plus;
+	u_int16_t alg, key_size, int_alg;
+	prf_t *rekey_prf = NULL;
+
+	spi_i = chunk_alloca(sizeof(u_int64_t));
+	spi_r = chunk_alloca(sizeof(u_int64_t));
+
+	if (dh->get_shared_secret(dh, &secret) != SUCCESS)
+	{
+		return FALSE;
+	}
+
+	/* Create SAs general purpose PRF first, we may use it here */
+	if (!proposal->get_algorithm(proposal, PSEUDO_RANDOM_FUNCTION, &alg, NULL))
+	{
+		DBG1(DBG_IKE, "no %N selected",
+			 transform_type_names, PSEUDO_RANDOM_FUNCTION);
+		return FALSE;
+	}
+	this->prf_alg = alg;
+	this->prf = lib->crypto->create_prf(lib->crypto, alg);
+	if (this->prf == NULL)
+	{
+		DBG1(DBG_IKE, "%N %N not supported!",
+			 transform_type_names, PSEUDO_RANDOM_FUNCTION,
+			 pseudo_random_function_names, alg);
+		return FALSE;
+	}
+	DBG4(DBG_IKE, "shared Diffie Hellman secret %B", &secret);
+	/* full nonce is used as seed for PRF+ ... */
+	full_nonce = chunk_cat("cc", nonce_i, nonce_r);
+	/* but the PRF may need a fixed key which only uses the first bytes of
+	 * the nonces. */
+	switch (alg)
+	{
+		case PRF_AES128_XCBC:
+			/* while rfc4434 defines variable keys for AES-XCBC, rfc3664 does
+			 * not and therefore fixed key semantics apply to XCBC for key
+			 * derivation. */
+		case PRF_CAMELLIA128_XCBC:
+			/* draft-kanno-ipsecme-camellia-xcbc refers to rfc 4434, we
+			 * assume fixed key length. */
+			key_size = this->prf->get_key_size(this->prf)/2;
+			nonce_i.len = min(nonce_i.len, key_size);
+			nonce_r.len = min(nonce_r.len, key_size);
+			break;
+		default:
+			/* all other algorithms use variable key length, full nonce */
+			break;
+	}
+	fixed_nonce = chunk_cat("cc", nonce_i, nonce_r);
+	*((u_int64_t*)spi_i.ptr) = id->get_initiator_spi(id);
+	*((u_int64_t*)spi_r.ptr) = id->get_responder_spi(id);
+	prf_plus_seed = chunk_cat("ccc", full_nonce, spi_i, spi_r);
+
+	/* KEYMAT = prf+ (SKEYSEED, Ni | Nr | SPIi | SPIr)
+	 *
+	 * if we are rekeying, SKEYSEED is built on another way
+	 */
+	if (rekey_function == PRF_UNDEFINED) /* not rekeying */
+	{
+		/* SKEYSEED = prf(Ni | Nr, g^ir) */
+		this->prf->set_key(this->prf, fixed_nonce);
+		this->prf->allocate_bytes(this->prf, secret, &skeyseed);
+		this->prf->set_key(this->prf, skeyseed);
+		prf_plus = prf_plus_create(this->prf, TRUE, prf_plus_seed);
+	}
+	else
+	{
+		/* SKEYSEED = prf(SK_d (old), [g^ir (new)] | Ni | Nr)
+		 * use OLD SAs PRF functions for both prf_plus and prf */
+		rekey_prf = lib->crypto->create_prf(lib->crypto, rekey_function);
+		if (!rekey_prf)
+		{
+			DBG1(DBG_IKE, "PRF of old SA %N not supported!",
+				 pseudo_random_function_names, rekey_function);
+			chunk_free(&full_nonce);
+			chunk_free(&fixed_nonce);
+			chunk_clear(&prf_plus_seed);
+			return FALSE;
+		}
+		secret = chunk_cat("mc", secret, full_nonce);
+		rekey_prf->set_key(rekey_prf, rekey_skd);
+		rekey_prf->allocate_bytes(rekey_prf, secret, &skeyseed);
+		rekey_prf->set_key(rekey_prf, skeyseed);
+		prf_plus = prf_plus_create(rekey_prf, TRUE, prf_plus_seed);
+	}
+	DBG4(DBG_IKE, "SKEYSEED %B", &skeyseed);
+
+	chunk_clear(&skeyseed);
+	chunk_clear(&secret);
+	chunk_free(&full_nonce);
+	chunk_free(&fixed_nonce);
+	chunk_clear(&prf_plus_seed);
+
+	/* KEYMAT = SK_d | SK_ai | SK_ar | SK_ei | SK_er | SK_pi | SK_pr */
+
+	/* SK_d is used for generating CHILD_SA key mat => store for later use */
+	key_size = this->prf->get_key_size(this->prf);
+	prf_plus->allocate_bytes(prf_plus, key_size, &this->skd);
+	DBG4(DBG_IKE, "Sk_d secret %B", &this->skd);
+
+	if (!proposal->get_algorithm(proposal, ENCRYPTION_ALGORITHM, &alg, &key_size))
+	{
+		DBG1(DBG_IKE, "no %N selected",
+			 transform_type_names, ENCRYPTION_ALGORITHM);
+		prf_plus->destroy(prf_plus);
+		DESTROY_IF(rekey_prf);
+		return FALSE;
+	}
+
+	if (encryption_algorithm_is_aead(alg))
+	{
+		if (!derive_ike_aead(this, alg, key_size, prf_plus))
+		{
+			prf_plus->destroy(prf_plus);
+			DESTROY_IF(rekey_prf);
+			return FALSE;
+		}
+	}
+	else
+	{
+		if (!proposal->get_algorithm(proposal, INTEGRITY_ALGORITHM,
+									 &int_alg, NULL))
+		{
+			DBG1(DBG_IKE, "no %N selected",
+				 transform_type_names, INTEGRITY_ALGORITHM);
+			prf_plus->destroy(prf_plus);
+			DESTROY_IF(rekey_prf);
+			return FALSE;
+		}
+		if (!derive_ike_traditional(this, alg, key_size, int_alg, prf_plus))
+		{
+			prf_plus->destroy(prf_plus);
+			DESTROY_IF(rekey_prf);
+			return FALSE;
+		}
+	}
+
+	/* SK_pi/SK_pr used for authentication => stored for later */
+	key_size = this->prf->get_key_size(this->prf);
+	prf_plus->allocate_bytes(prf_plus, key_size, &key);
+	DBG4(DBG_IKE, "Sk_pi secret %B", &key);
+	if (this->initiator)
+	{
+		this->skp_build = key;
+	}
+	else
+	{
+		this->skp_verify = key;
+	}
+	prf_plus->allocate_bytes(prf_plus, key_size, &key);
+	DBG4(DBG_IKE, "Sk_pr secret %B", &key);
+	if (this->initiator)
+	{
+		this->skp_verify = key;
+	}
+	else
+	{
+		this->skp_build = key;
+	}
+
+	/* all done, prf_plus not needed anymore */
+	prf_plus->destroy(prf_plus);
+	DESTROY_IF(rekey_prf);
+
+	return TRUE;
+}
+
+METHOD(keymat_v2_t, derive_child_keys, bool,
+	private_keymat_v2_t *this, proposal_t *proposal, diffie_hellman_t *dh,
+	chunk_t nonce_i, chunk_t nonce_r, chunk_t *encr_i, chunk_t *integ_i,
+	chunk_t *encr_r, chunk_t *integ_r)
+{
+	u_int16_t enc_alg, int_alg, enc_size = 0, int_size = 0;
+	chunk_t seed, secret = chunk_empty;
+	prf_plus_t *prf_plus;
+
+	if (dh)
+	{
+		if (dh->get_shared_secret(dh, &secret) != SUCCESS)
+		{
+			return FALSE;
+		}
+		DBG4(DBG_CHD, "DH secret %B", &secret);
+	}
+	seed = chunk_cata("mcc", secret, nonce_i, nonce_r);
+	DBG4(DBG_CHD, "seed %B", &seed);
+
+	if (proposal->get_algorithm(proposal, ENCRYPTION_ALGORITHM,
+								&enc_alg, &enc_size))
+	{
+		DBG2(DBG_CHD, "  using %N for encryption",
+			 encryption_algorithm_names, enc_alg);
+
+		if (!enc_size)
+		{
+			enc_size = keymat_get_keylen_encr(enc_alg);
+		}
+		if (enc_alg != ENCR_NULL && !enc_size)
+		{
+			DBG1(DBG_CHD, "no keylength defined for %N",
+				 encryption_algorithm_names, enc_alg);
+			return FALSE;
+		}
+		/* to bytes */
+		enc_size /= 8;
+
+		/* CCM/GCM/CTR/GMAC needs additional bytes */
+		switch (enc_alg)
+		{
+			case ENCR_AES_CCM_ICV8:
+			case ENCR_AES_CCM_ICV12:
+			case ENCR_AES_CCM_ICV16:
+			case ENCR_CAMELLIA_CCM_ICV8:
+			case ENCR_CAMELLIA_CCM_ICV12:
+			case ENCR_CAMELLIA_CCM_ICV16:
+				enc_size += 3;
+				break;
+			case ENCR_AES_GCM_ICV8:
+			case ENCR_AES_GCM_ICV12:
+			case ENCR_AES_GCM_ICV16:
+			case ENCR_AES_CTR:
+			case ENCR_NULL_AUTH_AES_GMAC:
+				enc_size += 4;
+				break;
+			default:
+				break;
+		}
+	}
+
+	if (proposal->get_algorithm(proposal, INTEGRITY_ALGORITHM,
+								&int_alg, &int_size))
+	{
+		DBG2(DBG_CHD, "  using %N for integrity",
+			 integrity_algorithm_names, int_alg);
+
+		if (!int_size)
+		{
+			int_size = keymat_get_keylen_integ(int_alg);
+		}
+		if (!int_size)
+		{
+			DBG1(DBG_CHD, "no keylength defined for %N",
+				 integrity_algorithm_names, int_alg);
+			return FALSE;
+		}
+		/* to bytes */
+		int_size /= 8;
+	}
+
+	this->prf->set_key(this->prf, this->skd);
+	prf_plus = prf_plus_create(this->prf, TRUE, seed);
+
+	prf_plus->allocate_bytes(prf_plus, enc_size, encr_i);
+	prf_plus->allocate_bytes(prf_plus, int_size, integ_i);
+	prf_plus->allocate_bytes(prf_plus, enc_size, encr_r);
+	prf_plus->allocate_bytes(prf_plus, int_size, integ_r);
+
+	prf_plus->destroy(prf_plus);
+
+	if (enc_size)
+	{
+		DBG4(DBG_CHD, "encryption initiator key %B", encr_i);
+		DBG4(DBG_CHD, "encryption responder key %B", encr_r);
+	}
+	if (int_size)
+	{
+		DBG4(DBG_CHD, "integrity initiator key %B", integ_i);
+		DBG4(DBG_CHD, "integrity responder key %B", integ_r);
+	}
+	return TRUE;
+}
+
+METHOD(keymat_v2_t, get_skd, pseudo_random_function_t,
+	private_keymat_v2_t *this, chunk_t *skd)
+{
+	*skd = this->skd;
+	return this->prf_alg;
+}
+
+METHOD(keymat_t, get_aead, aead_t*,
+	private_keymat_v2_t *this, bool in)
+{
+	return in ? this->aead_in : this->aead_out;
+}
+
+METHOD(keymat_v2_t, get_auth_octets, chunk_t,
+	private_keymat_v2_t *this, bool verify, chunk_t ike_sa_init,
+	chunk_t nonce, identification_t *id, char reserved[3])
+{
+	chunk_t chunk, idx, octets;
+	chunk_t skp;
+
+	skp = verify ? this->skp_verify : this->skp_build;
+
+	chunk = chunk_alloca(4);
+	chunk.ptr[0] = id->get_type(id);
+	memcpy(chunk.ptr + 1, reserved, 3);
+	idx = chunk_cata("cc", chunk, id->get_encoding(id));
+
+	DBG3(DBG_IKE, "IDx' %B", &idx);
+	DBG3(DBG_IKE, "SK_p %B", &skp);
+	this->prf->set_key(this->prf, skp);
+	this->prf->allocate_bytes(this->prf, idx, &chunk);
+
+	octets = chunk_cat("ccm", ike_sa_init, nonce, chunk);
+	DBG3(DBG_IKE, "octets = message + nonce + prf(Sk_px, IDx') %B", &octets);
+	return octets;
+}
+
+/**
+ * Key pad for the AUTH method SHARED_KEY_MESSAGE_INTEGRITY_CODE.
+ */
+#define IKEV2_KEY_PAD "Key Pad for IKEv2"
+#define IKEV2_KEY_PAD_LENGTH 17
+
+METHOD(keymat_v2_t, get_psk_sig, chunk_t,
+	private_keymat_v2_t *this, bool verify, chunk_t ike_sa_init,
+	chunk_t nonce, chunk_t secret, identification_t *id, char reserved[3])
+{
+	chunk_t key_pad, key, sig, octets;
+
+	if (!secret.len)
+	{	/* EAP uses SK_p if no MSK has been established */
+		secret = verify ? this->skp_verify : this->skp_build;
+	}
+	octets = get_auth_octets(this, verify, ike_sa_init, nonce, id, reserved);
+	/* AUTH = prf(prf(Shared Secret,"Key Pad for IKEv2"), <msg octets>) */
+	key_pad = chunk_create(IKEV2_KEY_PAD, IKEV2_KEY_PAD_LENGTH);
+	this->prf->set_key(this->prf, secret);
+	this->prf->allocate_bytes(this->prf, key_pad, &key);
+	this->prf->set_key(this->prf, key);
+	this->prf->allocate_bytes(this->prf, octets, &sig);
+	DBG4(DBG_IKE, "secret %B", &secret);
+	DBG4(DBG_IKE, "prf(secret, keypad) %B", &key);
+	DBG3(DBG_IKE, "AUTH = prf(prf(secret, keypad), octets) %B", &sig);
+	chunk_free(&octets);
+	chunk_free(&key);
+
+	return sig;
+}
+
+METHOD(keymat_t, destroy, void,
+	private_keymat_v2_t *this)
+{
+	DESTROY_IF(this->aead_in);
+	DESTROY_IF(this->aead_out);
+	DESTROY_IF(this->prf);
+	chunk_clear(&this->skd);
+	chunk_clear(&this->skp_verify);
+	chunk_clear(&this->skp_build);
+	free(this);
+}
+
+/**
+ * See header
+ */
+keymat_v2_t *keymat_v2_create(bool initiator)
+{
+	private_keymat_v2_t *this;
+
+	INIT(this,
+		.public = {
+			.keymat = {
+				.get_version = _get_version,
+				.create_dh = _create_dh,
+				.get_aead = _get_aead,
+				.destroy = _destroy,
+			},
+			.derive_ike_keys = _derive_ike_keys,
+			.derive_child_keys = _derive_child_keys,
+			.get_skd = _get_skd,
+			.get_auth_octets = _get_auth_octets,
+			.get_psk_sig = _get_psk_sig,
+		},
+		.initiator = initiator,
+		.prf_alg = PRF_UNDEFINED,
+	);
+
+	return &this->public;
+}