1 /* 2 * Copyright (c) 2000 Niels Provos. All rights reserved. 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 RCSID("$OpenBSD: kexgex.c,v 1.24 2005/11/04 05:15:59 djm Exp $"); 28 29 #include <openssl/evp.h> 30 31 #include "buffer.h" 32 #include "bufaux.h" 33 #include "kex.h" 34 #include "ssh2.h" 35 36 void 37 kexgex_hash( 38 const EVP_MD *evp_md, 39 char *client_version_string, 40 char *server_version_string, 41 char *ckexinit, int ckexinitlen, 42 char *skexinit, int skexinitlen, 43 u_char *serverhostkeyblob, int sbloblen, 44 int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen, 45 BIGNUM *client_dh_pub, 46 BIGNUM *server_dh_pub, 47 BIGNUM *shared_secret, 48 u_char **hash, u_int *hashlen) 49 { 50 Buffer b; 51 static u_char digest[EVP_MAX_MD_SIZE]; 52 EVP_MD_CTX md; 53 54 buffer_init(&b); 55 buffer_put_cstring(&b, client_version_string); 56 buffer_put_cstring(&b, server_version_string); 57 58 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 59 buffer_put_int(&b, ckexinitlen+1); 60 buffer_put_char(&b, SSH2_MSG_KEXINIT); 61 buffer_append(&b, ckexinit, ckexinitlen); 62 buffer_put_int(&b, skexinitlen+1); 63 buffer_put_char(&b, SSH2_MSG_KEXINIT); 64 buffer_append(&b, skexinit, skexinitlen); 65 66 buffer_put_string(&b, serverhostkeyblob, sbloblen); 67 if (min == -1 || max == -1) 68 buffer_put_int(&b, wantbits); 69 else { 70 buffer_put_int(&b, min); 71 buffer_put_int(&b, wantbits); 72 buffer_put_int(&b, max); 73 } 74 buffer_put_bignum2(&b, prime); 75 buffer_put_bignum2(&b, gen); 76 buffer_put_bignum2(&b, client_dh_pub); 77 buffer_put_bignum2(&b, server_dh_pub); 78 buffer_put_bignum2(&b, shared_secret); 79 80 #ifdef DEBUG_KEXDH 81 buffer_dump(&b); 82 #endif 83 84 EVP_DigestInit(&md, evp_md); 85 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 86 EVP_DigestFinal(&md, digest, NULL); 87 88 buffer_free(&b); 89 *hash = digest; 90 *hashlen = EVP_MD_size(evp_md); 91 #ifdef DEBUG_KEXDH 92 dump_digest("hash", digest, *hashlen); 93 #endif 94 } 95