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 <sys/types.h> 28 29 #include <openssl/evp.h> 30 #include <signal.h> 31 32 #include "buffer.h" 33 #include "key.h" 34 #include "cipher.h" 35 #include "kex.h" 36 #include "ssh2.h" 37 38 void 39 kexgex_hash( 40 const EVP_MD *evp_md, 41 char *client_version_string, 42 char *server_version_string, 43 char *ckexinit, int ckexinitlen, 44 char *skexinit, int skexinitlen, 45 u_char *serverhostkeyblob, int sbloblen, 46 int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen, 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 EVP_MD_CTX md; 55 56 buffer_init(&b); 57 buffer_put_cstring(&b, client_version_string); 58 buffer_put_cstring(&b, server_version_string); 59 60 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 61 buffer_put_int(&b, ckexinitlen+1); 62 buffer_put_char(&b, SSH2_MSG_KEXINIT); 63 buffer_append(&b, ckexinit, ckexinitlen); 64 buffer_put_int(&b, skexinitlen+1); 65 buffer_put_char(&b, SSH2_MSG_KEXINIT); 66 buffer_append(&b, skexinit, skexinitlen); 67 68 buffer_put_string(&b, serverhostkeyblob, sbloblen); 69 if (min == -1 || max == -1) 70 buffer_put_int(&b, wantbits); 71 else { 72 buffer_put_int(&b, min); 73 buffer_put_int(&b, wantbits); 74 buffer_put_int(&b, max); 75 } 76 buffer_put_bignum2(&b, prime); 77 buffer_put_bignum2(&b, gen); 78 buffer_put_bignum2(&b, client_dh_pub); 79 buffer_put_bignum2(&b, server_dh_pub); 80 buffer_put_bignum2(&b, shared_secret); 81 82 #ifdef DEBUG_KEXDH 83 buffer_dump(&b); 84 #endif 85 86 EVP_DigestInit(&md, evp_md); 87 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 88 EVP_DigestFinal(&md, digest, NULL); 89 90 buffer_free(&b); 91 *hash = digest; 92 *hashlen = EVP_MD_size(evp_md); 93 #ifdef DEBUG_KEXDH 94 dump_digest("hash", digest, *hashlen); 95 #endif 96 } 97