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 1.18 2002/03/18 17:50:31 provos Exp $"); 27 28 #pragma ident "%Z%%M% %I% %E% SMI" 29 30 #include <openssl/crypto.h> 31 #include <openssl/bn.h> 32 33 #include "xmalloc.h" 34 #include "buffer.h" 35 #include "bufaux.h" 36 #include "key.h" 37 #include "kex.h" 38 #include "log.h" 39 #include "packet.h" 40 #include "dh.h" 41 #include "ssh2.h" 42 43 u_char * 44 kex_dh_hash( 45 char *client_version_string, 46 char *server_version_string, 47 char *ckexinit, int ckexinitlen, 48 char *skexinit, int skexinitlen, 49 u_char *serverhostkeyblob, int sbloblen, 50 BIGNUM *client_dh_pub, 51 BIGNUM *server_dh_pub, 52 BIGNUM *shared_secret) 53 { 54 Buffer b; 55 static u_char digest[EVP_MAX_MD_SIZE]; 56 const EVP_MD *evp_md = EVP_sha1(); 57 EVP_MD_CTX md; 58 59 buffer_init(&b); 60 buffer_put_cstring(&b, client_version_string); 61 buffer_put_cstring(&b, server_version_string); 62 63 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 64 buffer_put_int(&b, ckexinitlen+1); 65 buffer_put_char(&b, SSH2_MSG_KEXINIT); 66 buffer_append(&b, ckexinit, ckexinitlen); 67 buffer_put_int(&b, skexinitlen+1); 68 buffer_put_char(&b, SSH2_MSG_KEXINIT); 69 buffer_append(&b, skexinit, skexinitlen); 70 71 buffer_put_string(&b, serverhostkeyblob, sbloblen); 72 buffer_put_bignum2(&b, client_dh_pub); 73 buffer_put_bignum2(&b, server_dh_pub); 74 buffer_put_bignum2(&b, shared_secret); 75 76 #ifdef DEBUG_KEX 77 buffer_dump(&b); 78 #endif 79 EVP_DigestInit(&md, evp_md); 80 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 81 EVP_DigestFinal(&md, digest, NULL); 82 83 buffer_free(&b); 84 85 #ifdef DEBUG_KEX 86 dump_digest("hash", digest, EVP_MD_size(evp_md)); 87 #endif 88 return digest; 89 } 90