Preliminary implementation of Elliptic Curve Diffie-Hellman Ephemeral key exchange.
This commit is contained in:
Guus Sliepen
parent
6c21b5716b
commit
ee8a214318
3 changed files with 121 additions and 2 deletions
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@ -11,7 +11,7 @@ tincd_SOURCES = \
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protocol_key.c protocol_subnet.c route.c subnet.c tincd.c
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nodist_tincd_SOURCES = \
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device.c cipher.c crypto.c digest.c rsa.c
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device.c cipher.c crypto.c ecdh.c digest.c rsa.c
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tincctl_SOURCES = \
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utils.c getopt.c getopt1.c dropin.c \
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@ -32,7 +32,7 @@ INCLUDES = @INCLUDES@ -I$(top_builddir)
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noinst_HEADERS = \
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xalloc.h utils.h getopt.h list.h splay_tree.h dropin.h fake-getaddrinfo.h fake-getnameinfo.h fake-gai-errnos.h ipv6.h ipv4.h ethernet.h \
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buffer.h cipher.h conf.h connection.h control.h control_common.h crypto.h device.h digest.h edge.h graph.h logger.h meta.h net.h netutl.h node.h process.h \
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buffer.h cipher.h conf.h connection.h control.h control_common.h crypto.h device.h ecdh.h digest.h edge.h graph.h logger.h meta.h net.h netutl.h node.h process.h \
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protocol.h route.h rsa.h rsagen.h subnet.h tincctl.h top.h bsd/tunemu.h
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LIBS = @LIBS@ @LIBGCRYPT_LIBS@
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87
src/openssl/ecdh.c
Normal file
87
src/openssl/ecdh.c
Normal file
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@ -0,0 +1,87 @@
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/*
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ecdh.c -- Diffie-Hellman key exchange handling
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Copyright (C) 2011 Guus Sliepen <guus@tinc-vpn.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "system.h"
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#include "utils.h"
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#include "xalloc.h"
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#include <openssl/err.h>
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#include <openssl/ec.h>
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#include <openssl/obj_mac.h>
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#include "ecdh.h"
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#include "logger.h"
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EC_GROUP *secp256k1 = NULL;
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EC_GROUP *secp384r1 = NULL;
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EC_GROUP *secp521r1 = NULL;
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// TODO: proper KDF
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static void *kdf(const void *in, size_t inlen, void *out, size_t *outlen) {
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memcpy(out, in, inlen);
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*outlen = inlen;
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return out;
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}
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bool ecdh_generate_public(ecdh_t *ecdh, void *pubkey) {
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if(!secp521r1)
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secp521r1 = EC_GROUP_new_by_curve_name(NID_secp521r1);
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*ecdh = EC_KEY_new_by_curve_name(NID_secp521r1);
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if(!EC_KEY_generate_key(*ecdh)) {
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logger(LOG_ERR, "Generating EC key failed: %s", ERR_error_string(ERR_get_error(), NULL));
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abort();
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}
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const EC_POINT *point = EC_KEY_get0_public_key(*ecdh);
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if(!point) {
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logger(LOG_ERR, "Getting public key failed: %s", ERR_error_string(ERR_get_error(), NULL));
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abort();
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}
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size_t result = EC_POINT_point2oct(secp521r1, point, POINT_CONVERSION_COMPRESSED, pubkey, ECDH_SIZE, NULL);
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if(!result) {
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logger(LOG_ERR, "Converting EC_POINT to binary failed: %s", ERR_error_string(ERR_get_error(), NULL));
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abort();
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}
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return true;
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}
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bool ecdh_compute_shared(ecdh_t *ecdh, const void *pubkey, void *shared) {
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EC_POINT *point = EC_POINT_new(secp521r1);
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int result = EC_POINT_oct2point(secp521r1, point, pubkey, ECDH_SIZE, NULL);
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if(!point) {
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logger(LOG_ERR, "Converting binary to EC_POINT failed: %s", ERR_error_string(ERR_get_error(), NULL));
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abort();
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}
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result = ECDH_compute_key(shared, ECDH_SIZE, point, *ecdh, kdf);
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EC_POINT_free(point);
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EC_KEY_free(*ecdh);
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*ecdh = NULL;
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if(!result) {
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logger(LOG_ERR, "Computing Elliptic Curve Diffie-Hellman shared key failed: %s", ERR_error_string(ERR_get_error(), NULL));
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return false;
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}
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return true;
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}
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32
src/openssl/ecdh.h
Normal file
32
src/openssl/ecdh.h
Normal file
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@ -0,0 +1,32 @@
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/*
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ecdh.h -- header file for ecdh.c
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Copyright (C) 2011 Guus Sliepen <guus@tinc-vpn.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef __TINC_ECDH_H__
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#define __TINC_ECDH_H__
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#include <openssl/ecdh.h>
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#define ECDH_SIZE 67
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typedef EC_KEY *ecdh_t;
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extern bool ecdh_generate_public(ecdh_t *ecdh, void *pubkey);
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extern bool ecdh_compute_shared(ecdh_t *ecdh, const void *pubkey, void *shared);
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#endif
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