1 /* $OpenBSD: kexdh.c,v 1.26 2016/05/02 10:26:04 djm 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 <sys/types.h> 27 28 #include <signal.h> 29 30 #include <openssl/evp.h> 31 32 #include "ssh2.h" 33 #include "sshkey.h" 34 #include "cipher.h" 35 #include "kex.h" 36 #include "ssherr.h" 37 #include "sshbuf.h" 38 #include "digest.h" 39 40 int 41 kex_dh_hash( 42 int hash_alg, 43 const char *client_version_string, 44 const char *server_version_string, 45 const u_char *ckexinit, size_t ckexinitlen, 46 const u_char *skexinit, size_t skexinitlen, 47 const u_char *serverhostkeyblob, size_t sbloblen, 48 const BIGNUM *client_dh_pub, 49 const BIGNUM *server_dh_pub, 50 const BIGNUM *shared_secret, 51 u_char *hash, size_t *hashlen) 52 { 53 struct sshbuf *b; 54 int r; 55 56 if (*hashlen < ssh_digest_bytes(hash_alg)) 57 return SSH_ERR_INVALID_ARGUMENT; 58 if ((b = sshbuf_new()) == NULL) 59 return SSH_ERR_ALLOC_FAIL; 60 if ((r = sshbuf_put_cstring(b, client_version_string)) != 0 || 61 (r = sshbuf_put_cstring(b, server_version_string)) != 0 || 62 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 63 (r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 || 64 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 || 65 (r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 || 66 (r = sshbuf_put_u32(b, skexinitlen+1)) != 0 || 67 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 || 68 (r = sshbuf_put(b, skexinit, skexinitlen)) != 0 || 69 (r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 || 70 (r = sshbuf_put_bignum2(b, client_dh_pub)) != 0 || 71 (r = sshbuf_put_bignum2(b, server_dh_pub)) != 0 || 72 (r = sshbuf_put_bignum2(b, shared_secret)) != 0) { 73 sshbuf_free(b); 74 return r; 75 } 76 #ifdef DEBUG_KEX 77 sshbuf_dump(b, stderr); 78 #endif 79 if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) { 80 sshbuf_free(b); 81 return SSH_ERR_LIBCRYPTO_ERROR; 82 } 83 sshbuf_free(b); 84 *hashlen = ssh_digest_bytes(hash_alg); 85 #ifdef DEBUG_KEX 86 dump_digest("hash", hash, *hashlen); 87 #endif 88 return 0; 89 } 90