1 /* 2 * Copyright (c) 2001 Markus Friedl. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23 */ 24 25 #include "includes.h" 26 RCSID("$OpenBSD: kexdh.c,v 1.19 2003/02/16 17:09:57 markus Exp $"); 27 28 #include <openssl/evp.h> 29 30 #include "buffer.h" 31 #include "bufaux.h" 32 #include "ssh2.h" 33 #include "kex.h" 34 35 u_char * 36 kex_dh_hash( 37 char *client_version_string, 38 char *server_version_string, 39 char *ckexinit, int ckexinitlen, 40 char *skexinit, int skexinitlen, 41 u_char *serverhostkeyblob, int sbloblen, 42 BIGNUM *client_dh_pub, 43 BIGNUM *server_dh_pub, 44 BIGNUM *shared_secret) 45 { 46 Buffer b; 47 static u_char digest[EVP_MAX_MD_SIZE]; 48 const EVP_MD *evp_md = EVP_sha1(); 49 EVP_MD_CTX md; 50 51 buffer_init(&b); 52 buffer_put_cstring(&b, client_version_string); 53 buffer_put_cstring(&b, server_version_string); 54 55 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 56 buffer_put_int(&b, ckexinitlen+1); 57 buffer_put_char(&b, SSH2_MSG_KEXINIT); 58 buffer_append(&b, ckexinit, ckexinitlen); 59 buffer_put_int(&b, skexinitlen+1); 60 buffer_put_char(&b, SSH2_MSG_KEXINIT); 61 buffer_append(&b, skexinit, skexinitlen); 62 63 buffer_put_string(&b, serverhostkeyblob, sbloblen); 64 buffer_put_bignum2(&b, client_dh_pub); 65 buffer_put_bignum2(&b, server_dh_pub); 66 buffer_put_bignum2(&b, shared_secret); 67 68 #ifdef DEBUG_KEX 69 buffer_dump(&b); 70 #endif 71 EVP_DigestInit(&md, evp_md); 72 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 73 EVP_DigestFinal(&md, digest, NULL); 74 75 buffer_free(&b); 76 77 #ifdef DEBUG_KEX 78 dump_digest("hash", digest, EVP_MD_size(evp_md)); 79 #endif 80 return digest; 81 } 82