split dh API functions from ui.c

1 files changed, 393 insertions, 0 deletions

diff --git a/lib/dh-session.c b/lib/dh-session.c
new file mode 100644
index 0000000000..483341af41
--- /dev/null
+++ b/lib/dh-session.c
@@ -0,0 +1,393 @@
+/*
+ * Copyright (C) 2001-2015 Free Software Foundation, Inc.
+ * Copyright (C) 2015 Nikos Mavrogiannopoulos
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+/* This file contains certificate authentication functions to be exported in the
+ * API which did not fit elsewhere.
+ */
+
+#include "gnutls_int.h"
+#include <auth/srp_kx.h>
+#include <auth/anon.h>
+#include <auth/cert.h>
+#include <auth/psk.h>
+#include "errors.h"
+#include <auth.h>
+#include <state.h>
+#include <datum.h>
+#include <algorithms.h>
+
+/* ANON & DHE */
+
+#if defined(ENABLE_DHE) || defined(ENABLE_ANON)
+/**
+ * gnutls_dh_set_prime_bits:
+ * @session: is a #gnutls_session_t type.
+ * @bits: is the number of bits
+ *
+ * This function sets the number of bits, for use in a Diffie-Hellman
+ * key exchange.  This is used both in DH ephemeral and DH anonymous
+ * cipher suites.  This will set the minimum size of the prime that
+ * will be used for the handshake.
+ *
+ * In the client side it sets the minimum accepted number of bits.  If
+ * a server sends a prime with less bits than that
+ * %GNUTLS_E_DH_PRIME_UNACCEPTABLE will be returned by the handshake.
+ *
+ * Note that this function will warn via the audit log for value that
+ * are believed to be weak.
+ *
+ * The function has no effect in server side.
+ * 
+ * Note that since 3.1.7 this function is deprecated. The minimum
+ * number of bits is set by the priority string level.
+ * Also this function must be called after gnutls_priority_set_direct()
+ * or the set value may be overridden by the selected priority options.
+ *
+ *
+ **/
+void gnutls_dh_set_prime_bits(gnutls_session_t session, unsigned int bits)
+{
+	if (bits < gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_WEAK)
+		&& bits != 0)
+		_gnutls_audit_log(session,
+				  "Note that the security level of the Diffie-Hellman key exchange has been lowered to %u bits and this may allow decryption of the session data\n",
+				  bits);
+	session->internals.priorities.dh_prime_bits = bits;
+}
+
+
+/**
+ * gnutls_dh_get_group:
+ * @session: is a gnutls session
+ * @raw_gen: will hold the generator.
+ * @raw_prime: will hold the prime.
+ *
+ * This function will return the group parameters used in the last
+ * Diffie-Hellman key exchange with the peer.  These are the prime and
+ * the generator used.  This function should be used for both
+ * anonymous and ephemeral Diffie-Hellman.  The output parameters must
+ * be freed with gnutls_free().
+ *
+ * Note, that the prime and generator are exported as non-negative
+ * integers and may include a leading zero byte.
+ *
+ * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise
+ *   an error code is returned.
+ **/
+int
+gnutls_dh_get_group(gnutls_session_t session,
+		    gnutls_datum_t * raw_gen, gnutls_datum_t * raw_prime)
+{
+	dh_info_st *dh;
+	int ret;
+	anon_auth_info_t anon_info;
+	cert_auth_info_t cert_info;
+	psk_auth_info_t psk_info;
+
+	switch (gnutls_auth_get_type(session)) {
+	case GNUTLS_CRD_ANON:
+		anon_info = _gnutls_get_auth_info(session, GNUTLS_CRD_ANON);
+		if (anon_info == NULL)
+			return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+		dh = &anon_info->dh;
+		break;
+	case GNUTLS_CRD_PSK:
+		psk_info = _gnutls_get_auth_info(session, GNUTLS_CRD_PSK);
+		if (psk_info == NULL)
+			return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+		dh = &psk_info->dh;
+		break;
+	case GNUTLS_CRD_CERTIFICATE:
+		cert_info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE);
+		if (cert_info == NULL)
+			return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+		dh = &cert_info->dh;
+		break;
+	default:
+		gnutls_assert();
+		return GNUTLS_E_INVALID_REQUEST;
+	}
+
+	ret = _gnutls_set_datum(raw_prime, dh->prime.data, dh->prime.size);
+	if (ret < 0) {
+		gnutls_assert();
+		return ret;
+	}
+
+	ret =
+	    _gnutls_set_datum(raw_gen, dh->generator.data,
+			      dh->generator.size);
+	if (ret < 0) {
+		gnutls_assert();
+		_gnutls_free_datum(raw_prime);
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * gnutls_dh_get_pubkey:
+ * @session: is a gnutls session
+ * @raw_key: will hold the public key.
+ *
+ * This function will return the peer's public key used in the last
+ * Diffie-Hellman key exchange.  This function should be used for both
+ * anonymous and ephemeral Diffie-Hellman.  The output parameters must
+ * be freed with gnutls_free().
+ *
+ * Note, that public key is exported as non-negative
+ * integer and may include a leading zero byte.
+ *
+ * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise
+ *   an error code is returned.
+ **/
+int
+gnutls_dh_get_pubkey(gnutls_session_t session, gnutls_datum_t * raw_key)
+{
+	dh_info_st *dh;
+	anon_auth_info_t anon_info;
+	cert_auth_info_t cert_info;
+	cert_auth_info_t psk_info;
+
+	switch (gnutls_auth_get_type(session)) {
+	case GNUTLS_CRD_ANON:
+		{
+			anon_info = _gnutls_get_auth_info(session, GNUTLS_CRD_ANON);
+			if (anon_info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+			dh = &anon_info->dh;
+			break;
+		}
+	case GNUTLS_CRD_PSK:
+		{
+			psk_info = _gnutls_get_auth_info(session, GNUTLS_CRD_PSK);
+			if (psk_info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+			dh = &psk_info->dh;
+			break;
+		}
+	case GNUTLS_CRD_CERTIFICATE:
+		{
+
+			cert_info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE);
+			if (cert_info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+			dh = &cert_info->dh;
+			break;
+		}
+	default:
+		gnutls_assert();
+		return GNUTLS_E_INVALID_REQUEST;
+	}
+
+	return _gnutls_set_datum(raw_key, dh->public_key.data,
+				 dh->public_key.size);
+}
+
+/**
+ * gnutls_dh_get_secret_bits:
+ * @session: is a gnutls session
+ *
+ * This function will return the bits used in the last Diffie-Hellman
+ * key exchange with the peer.  Should be used for both anonymous and
+ * ephemeral Diffie-Hellman.
+ *
+ * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise
+ *   an error code is returned.
+ **/
+int gnutls_dh_get_secret_bits(gnutls_session_t session)
+{
+	switch (gnutls_auth_get_type(session)) {
+	case GNUTLS_CRD_ANON:
+		{
+			anon_auth_info_t info;
+
+			info = _gnutls_get_auth_info(session, GNUTLS_CRD_ANON);
+			if (info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+			return info->dh.secret_bits;
+		}
+	case GNUTLS_CRD_PSK:
+		{
+			psk_auth_info_t info;
+
+			info = _gnutls_get_auth_info(session, GNUTLS_CRD_PSK);
+			if (info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+			return info->dh.secret_bits;
+		}
+	case GNUTLS_CRD_CERTIFICATE:
+		{
+			cert_auth_info_t info;
+
+			info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE);
+			if (info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+			return info->dh.secret_bits;
+		}
+	default:
+		gnutls_assert();
+		return GNUTLS_E_INVALID_REQUEST;
+	}
+}
+
+
+static int mpi_buf2bits(gnutls_datum_t * mpi_buf)
+{
+	bigint_t mpi;
+	int rc;
+
+	rc = _gnutls_mpi_init_scan_nz(&mpi, mpi_buf->data, mpi_buf->size);
+	if (rc) {
+		gnutls_assert();
+		return rc;
+	}
+
+	rc = _gnutls_mpi_get_nbits(mpi);
+	_gnutls_mpi_release(&mpi);
+
+	return rc;
+}
+
+/**
+ * gnutls_dh_get_prime_bits:
+ * @session: is a gnutls session
+ *
+ * This function will return the bits of the prime used in the last
+ * Diffie-Hellman key exchange with the peer.  Should be used for both
+ * anonymous and ephemeral Diffie-Hellman.  Note that some ciphers,
+ * like RSA and DSA without DHE, do not use a Diffie-Hellman key
+ * exchange, and then this function will return 0.
+ *
+ * Returns: The Diffie-Hellman bit strength is returned, or 0 if no
+ *   Diffie-Hellman key exchange was done, or a negative error code on
+ *   failure.
+ **/
+int gnutls_dh_get_prime_bits(gnutls_session_t session)
+{
+	dh_info_st *dh;
+
+	switch (gnutls_auth_get_type(session)) {
+	case GNUTLS_CRD_ANON:
+		{
+			anon_auth_info_t info;
+
+			info = _gnutls_get_auth_info(session, GNUTLS_CRD_ANON);
+			if (info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+			dh = &info->dh;
+			break;
+		}
+	case GNUTLS_CRD_PSK:
+		{
+			psk_auth_info_t info;
+
+			info = _gnutls_get_auth_info(session, GNUTLS_CRD_PSK);
+			if (info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+			dh = &info->dh;
+			break;
+		}
+	case GNUTLS_CRD_CERTIFICATE:
+		{
+			cert_auth_info_t info;
+
+			info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE);
+			if (info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+			dh = &info->dh;
+			break;
+		}
+	default:
+		gnutls_assert();
+		return GNUTLS_E_INVALID_REQUEST;
+	}
+
+	if(dh->prime.size == 0)
+		return 0;
+
+	return mpi_buf2bits(&dh->prime);
+}
+
+
+/**
+ * gnutls_dh_get_peers_public_bits:
+ * @session: is a gnutls session
+ *
+ * Get the Diffie-Hellman public key bit size.  Can be used for both
+ * anonymous and ephemeral Diffie-Hellman.
+ *
+ * Returns: The public key bit size used in the last Diffie-Hellman
+ *   key exchange with the peer, or a negative error code in case of error.
+ **/
+int gnutls_dh_get_peers_public_bits(gnutls_session_t session)
+{
+	dh_info_st *dh;
+
+	switch (gnutls_auth_get_type(session)) {
+	case GNUTLS_CRD_ANON:
+		{
+			anon_auth_info_t info;
+
+			info = _gnutls_get_auth_info(session, GNUTLS_CRD_ANON);
+			if (info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+			dh = &info->dh;
+			break;
+		}
+	case GNUTLS_CRD_PSK:
+		{
+			psk_auth_info_t info;
+
+			info = _gnutls_get_auth_info(session, GNUTLS_CRD_PSK);
+			if (info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+			dh = &info->dh;
+			break;
+		}
+	case GNUTLS_CRD_CERTIFICATE:
+		{
+			cert_auth_info_t info;
+
+			info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE);
+			if (info == NULL)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+			dh = &info->dh;
+			break;
+		}
+	default:
+		gnutls_assert();
+		return GNUTLS_E_INVALID_REQUEST;
+	}
+
+	return mpi_buf2bits(&dh->public_key);
+}
+
+#endif				/* DH */
+