1 /* $OpenBSD: kexgex.c,v 1.27 2006/08/03 03:34:42 deraadt Exp $ */ 2 /* 3 * Copyright (c) 2000 Niels Provos. All rights reserved. 4 * Copyright (c) 2001 Markus Friedl. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "includes.h" 28 29 #include <sys/types.h> 30 31 #include <openssl/evp.h> 32 #include <signal.h> 33 34 #include "buffer.h" 35 #include "key.h" 36 #include "cipher.h" 37 #include "kex.h" 38 #include "ssh2.h" 39 40 void 41 kexgex_hash( 42 const EVP_MD *evp_md, 43 char *client_version_string, 44 char *server_version_string, 45 char *ckexinit, int ckexinitlen, 46 char *skexinit, int skexinitlen, 47 u_char *serverhostkeyblob, int sbloblen, 48 int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen, 49 BIGNUM *client_dh_pub, 50 BIGNUM *server_dh_pub, 51 BIGNUM *shared_secret, 52 u_char **hash, u_int *hashlen) 53 { 54 Buffer b; 55 static u_char digest[EVP_MAX_MD_SIZE]; 56 EVP_MD_CTX md; 57 58 buffer_init(&b); 59 buffer_put_cstring(&b, client_version_string); 60 buffer_put_cstring(&b, server_version_string); 61 62 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 63 buffer_put_int(&b, ckexinitlen+1); 64 buffer_put_char(&b, SSH2_MSG_KEXINIT); 65 buffer_append(&b, ckexinit, ckexinitlen); 66 buffer_put_int(&b, skexinitlen+1); 67 buffer_put_char(&b, SSH2_MSG_KEXINIT); 68 buffer_append(&b, skexinit, skexinitlen); 69 70 buffer_put_string(&b, serverhostkeyblob, sbloblen); 71 if (min == -1 || max == -1) 72 buffer_put_int(&b, wantbits); 73 else { 74 buffer_put_int(&b, min); 75 buffer_put_int(&b, wantbits); 76 buffer_put_int(&b, max); 77 } 78 buffer_put_bignum2(&b, prime); 79 buffer_put_bignum2(&b, gen); 80 buffer_put_bignum2(&b, client_dh_pub); 81 buffer_put_bignum2(&b, server_dh_pub); 82 buffer_put_bignum2(&b, shared_secret); 83 84 #ifdef DEBUG_KEXDH 85 buffer_dump(&b); 86 #endif 87 88 EVP_DigestInit(&md, evp_md); 89 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 90 EVP_DigestFinal(&md, digest, NULL); 91 92 buffer_free(&b); 93 *hash = digest; 94 *hashlen = EVP_MD_size(evp_md); 95 #ifdef DEBUG_KEXDH 96 dump_digest("hash", digest, *hashlen); 97 #endif 98 } 99