1 /* $OpenBSD: kexecdh.c,v 1.6 2015/01/19 20:16:15 markus Exp $ */ 2 /* 3 * Copyright (c) 2001 Markus Friedl. All rights reserved. 4 * Copyright (c) 2010 Damien Miller. 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 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) 30 31 #include <sys/types.h> 32 33 #include <signal.h> 34 #include <string.h> 35 36 #include <openssl/bn.h> 37 #include <openssl/evp.h> 38 #include <openssl/ec.h> 39 #include <openssl/ecdh.h> 40 41 #include "ssh2.h" 42 #include "sshkey.h" 43 #include "cipher.h" 44 #include "kex.h" 45 #include "sshbuf.h" 46 #include "digest.h" 47 #include "ssherr.h" 48 49 int 50 kex_ecdh_hash( 51 int hash_alg, 52 const EC_GROUP *ec_group, 53 const char *client_version_string, 54 const char *server_version_string, 55 const u_char *ckexinit, size_t ckexinitlen, 56 const u_char *skexinit, size_t skexinitlen, 57 const u_char *serverhostkeyblob, size_t sbloblen, 58 const EC_POINT *client_dh_pub, 59 const EC_POINT *server_dh_pub, 60 const BIGNUM *shared_secret, 61 u_char *hash, size_t *hashlen) 62 { 63 struct sshbuf *b; 64 int r; 65 66 if (*hashlen < ssh_digest_bytes(hash_alg)) 67 return SSH_ERR_INVALID_ARGUMENT; 68 if ((b = sshbuf_new()) == NULL) 69 return SSH_ERR_ALLOC_FAIL; 70 if ((r = sshbuf_put_cstring(b, client_version_string)) != 0 || 71 (r = sshbuf_put_cstring(b, server_version_string)) != 0 || 72 /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ 73 (r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 || 74 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 || 75 (r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 || 76 (r = sshbuf_put_u32(b, skexinitlen+1)) != 0 || 77 (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 || 78 (r = sshbuf_put(b, skexinit, skexinitlen)) != 0 || 79 (r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 || 80 (r = sshbuf_put_ec(b, client_dh_pub, ec_group)) != 0 || 81 (r = sshbuf_put_ec(b, server_dh_pub, ec_group)) != 0 || 82 (r = sshbuf_put_bignum2(b, shared_secret)) != 0) { 83 sshbuf_free(b); 84 return r; 85 } 86 #ifdef DEBUG_KEX 87 sshbuf_dump(b, stderr); 88 #endif 89 if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) { 90 sshbuf_free(b); 91 return SSH_ERR_LIBCRYPTO_ERROR; 92 } 93 sshbuf_free(b); 94 *hashlen = ssh_digest_bytes(hash_alg); 95 #ifdef DEBUG_KEX 96 dump_digest("hash", hash, *hashlen); 97 #endif 98 return 0; 99 } 100 #endif /* defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) */ 101