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Annotation of src/usr.bin/ssh/kexecdh.c, Revision 1.4

1.4     ! djm         1: /* $OpenBSD: kexecdh.c,v 1.3 2010/09/22 05:01:29 djm Exp $ */
1.1       djm         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 <sys/types.h>
                     28:
                     29: #include <signal.h>
                     30: #include <string.h>
                     31:
                     32: #include <openssl/bn.h>
                     33: #include <openssl/evp.h>
                     34: #include <openssl/ec.h>
                     35: #include <openssl/ecdh.h>
                     36:
                     37: #include "buffer.h"
                     38: #include "ssh2.h"
                     39: #include "key.h"
                     40: #include "cipher.h"
                     41: #include "kex.h"
                     42: #include "log.h"
                     43:
                     44: void
                     45: kex_ecdh_hash(
                     46:     const EVP_MD *evp_md,
                     47:     const EC_GROUP *ec_group,
                     48:     char *client_version_string,
                     49:     char *server_version_string,
                     50:     char *ckexinit, int ckexinitlen,
                     51:     char *skexinit, int skexinitlen,
                     52:     u_char *serverhostkeyblob, int sbloblen,
                     53:     const EC_POINT *client_dh_pub,
                     54:     const EC_POINT *server_dh_pub,
                     55:     const BIGNUM *shared_secret,
                     56:     u_char **hash, u_int *hashlen)
                     57: {
                     58:        Buffer b;
                     59:        EVP_MD_CTX md;
                     60:        static u_char digest[EVP_MAX_MD_SIZE];
                     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:        buffer_put_ecpoint(&b, ec_group, client_dh_pub);
                     76:        buffer_put_ecpoint(&b, ec_group, server_dh_pub);
                     77:        buffer_put_bignum2(&b, shared_secret);
                     78:
                     79: #ifdef DEBUG_KEX
                     80:        buffer_dump(&b);
                     81: #endif
                     82:        EVP_DigestInit(&md, evp_md);
                     83:        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
                     84:        EVP_DigestFinal(&md, digest, NULL);
                     85:
                     86:        buffer_free(&b);
                     87:
                     88: #ifdef DEBUG_KEX
                     89:        dump_digest("hash", digest, EVP_MD_size(evp_md));
                     90: #endif
                     91:        *hash = digest;
                     92:        *hashlen = EVP_MD_size(evp_md);
                     93: }
                     94: