1 /* $OpenBSD: kexecdh.c,v 1.4 2013/04/19 01:06:50 djm Exp $ */ 2 /* 3 * Copyright (c) 2001 Markus Friedl. All rights reserved. 4 * Copyright (c) 2010 Damien Miller. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "includes.h" 28 29 #ifdef OPENSSL_HAS_ECC 30 31 #include <sys/types.h> 32 33 #include <signal.h> 34 #include <string.h> 35 36 #include <openssl/bn.h> 37 #include <openssl/evp.h> 38 #include <openssl/ec.h> 39 #include <openssl/ecdh.h> 40 41 #include "buffer.h" 42 #include "ssh2.h" 43 #include "key.h" 44 #include "cipher.h" 45 #include "kex.h" 46 #include "log.h" 47 48 void 49 kex_ecdh_hash( 50 const EVP_MD *evp_md, 51 const EC_GROUP *ec_group, 52 char *client_version_string, 53 char *server_version_string, 54 char *ckexinit, int ckexinitlen, 55 char *skexinit, int skexinitlen, 56 u_char *serverhostkeyblob, int sbloblen, 57 const EC_POINT *client_dh_pub, 58 const EC_POINT *server_dh_pub, 59 const BIGNUM *shared_secret, 60 u_char **hash, u_int *hashlen) 61 { 62 Buffer b; 63 EVP_MD_CTX md; 64 static u_char digest[EVP_MAX_MD_SIZE]; 65 66 buffer_init(&b); 67 buffer_put_cstring(&b, client_version_string); 68 buffer_put_cstring(&b, server_version_string); 69 70 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 71 buffer_put_int(&b, ckexinitlen+1); 72 buffer_put_char(&b, SSH2_MSG_KEXINIT); 73 buffer_append(&b, ckexinit, ckexinitlen); 74 buffer_put_int(&b, skexinitlen+1); 75 buffer_put_char(&b, SSH2_MSG_KEXINIT); 76 buffer_append(&b, skexinit, skexinitlen); 77 78 buffer_put_string(&b, serverhostkeyblob, sbloblen); 79 buffer_put_ecpoint(&b, ec_group, client_dh_pub); 80 buffer_put_ecpoint(&b, ec_group, server_dh_pub); 81 buffer_put_bignum2(&b, shared_secret); 82 83 #ifdef DEBUG_KEX 84 buffer_dump(&b); 85 #endif 86 EVP_DigestInit(&md, evp_md); 87 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 88 EVP_DigestFinal(&md, digest, NULL); 89 90 buffer_free(&b); 91 92 #ifdef DEBUG_KEX 93 dump_digest("hash", digest, EVP_MD_size(evp_md)); 94 #endif 95 *hash = digest; 96 *hashlen = EVP_MD_size(evp_md); 97 } 98 99 #endif /* OPENSSL_HAS_ECC */ 100