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 1.22 2002/03/24 17:27:03 stevesk Exp $"); 28 29 #pragma ident "%Z%%M% %I% %E% SMI" 30 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 #include "compat.h" 43 #include "monitor_wrap.h" 44 45 u_char * 46 kexgex_hash( 47 char *client_version_string, 48 char *server_version_string, 49 char *ckexinit, int ckexinitlen, 50 char *skexinit, int skexinitlen, 51 u_char *serverhostkeyblob, int sbloblen, 52 int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen, 53 BIGNUM *client_dh_pub, 54 BIGNUM *server_dh_pub, 55 BIGNUM *shared_secret) 56 { 57 Buffer b; 58 static u_char digest[EVP_MAX_MD_SIZE]; 59 const EVP_MD *evp_md = EVP_sha1(); 60 EVP_MD_CTX md; 61 62 buffer_init(&b); 63 buffer_put_cstring(&b, client_version_string); 64 buffer_put_cstring(&b, server_version_string); 65 66 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 67 buffer_put_int(&b, ckexinitlen+1); 68 buffer_put_char(&b, SSH2_MSG_KEXINIT); 69 buffer_append(&b, ckexinit, ckexinitlen); 70 buffer_put_int(&b, skexinitlen+1); 71 buffer_put_char(&b, SSH2_MSG_KEXINIT); 72 buffer_append(&b, skexinit, skexinitlen); 73 74 buffer_put_string(&b, serverhostkeyblob, sbloblen); 75 if (min == -1 || max == -1) 76 buffer_put_int(&b, wantbits); 77 else { 78 buffer_put_int(&b, min); 79 buffer_put_int(&b, wantbits); 80 buffer_put_int(&b, max); 81 } 82 buffer_put_bignum2(&b, prime); 83 buffer_put_bignum2(&b, gen); 84 buffer_put_bignum2(&b, client_dh_pub); 85 buffer_put_bignum2(&b, server_dh_pub); 86 buffer_put_bignum2(&b, shared_secret); 87 88 #ifdef DEBUG_KEXDH 89 buffer_dump(&b); 90 #endif 91 EVP_DigestInit(&md, evp_md); 92 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 93 EVP_DigestFinal(&md, digest, NULL); 94 95 buffer_free(&b); 96 97 #ifdef DEBUG_KEXDH 98 dump_digest("hash", digest, EVP_MD_size(evp_md)); 99 #endif 100 return digest; 101 } 102