1 /* $OpenBSD: kexdh.c,v 1.23 2006/08/03 03:34:42 deraadt Exp $ */ 2 /* 3 * Copyright (c) 2001 Markus Friedl. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include "includes.h" 27 28 #include <sys/types.h> 29 30 #include <signal.h> 31 32 #include <openssl/evp.h> 33 34 #include "buffer.h" 35 #include "ssh2.h" 36 #include "key.h" 37 #include "cipher.h" 38 #include "kex.h" 39 40 void 41 kex_dh_hash( 42 char *client_version_string, 43 char *server_version_string, 44 char *ckexinit, int ckexinitlen, 45 char *skexinit, int skexinitlen, 46 u_char *serverhostkeyblob, int sbloblen, 47 BIGNUM *client_dh_pub, 48 BIGNUM *server_dh_pub, 49 BIGNUM *shared_secret, 50 u_char **hash, u_int *hashlen) 51 { 52 Buffer b; 53 static u_char digest[EVP_MAX_MD_SIZE]; 54 const EVP_MD *evp_md = EVP_sha1(); 55 EVP_MD_CTX md; 56 57 buffer_init(&b); 58 buffer_put_cstring(&b, client_version_string); 59 buffer_put_cstring(&b, server_version_string); 60 61 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 62 buffer_put_int(&b, ckexinitlen+1); 63 buffer_put_char(&b, SSH2_MSG_KEXINIT); 64 buffer_append(&b, ckexinit, ckexinitlen); 65 buffer_put_int(&b, skexinitlen+1); 66 buffer_put_char(&b, SSH2_MSG_KEXINIT); 67 buffer_append(&b, skexinit, skexinitlen); 68 69 buffer_put_string(&b, serverhostkeyblob, sbloblen); 70 buffer_put_bignum2(&b, client_dh_pub); 71 buffer_put_bignum2(&b, server_dh_pub); 72 buffer_put_bignum2(&b, shared_secret); 73 74 #ifdef DEBUG_KEX 75 buffer_dump(&b); 76 #endif 77 EVP_DigestInit(&md, evp_md); 78 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 79 EVP_DigestFinal(&md, digest, NULL); 80 81 buffer_free(&b); 82 83 #ifdef DEBUG_KEX 84 dump_digest("hash", digest, EVP_MD_size(evp_md)); 85 #endif 86 *hash = digest; 87 *hashlen = EVP_MD_size(evp_md); 88 } 89