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      1 /* $OpenBSD: kexgex.c,v 1.29 2015/01/19 20:16:15 markus 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 #ifdef WITH_OPENSSL
     30 
     31 #include <sys/types.h>
     32 
     33 #include <openssl/evp.h>
     34 #include <signal.h>
     35 
     36 #include "sshkey.h"
     37 #include "cipher.h"
     38 #include "kex.h"
     39 #include "ssh2.h"
     40 #include "ssherr.h"
     41 #include "sshbuf.h"
     42 #include "digest.h"
     43 
     44 int
     45 kexgex_hash(
     46     int hash_alg,
     47     const char *client_version_string,
     48     const char *server_version_string,
     49     const u_char *ckexinit, size_t ckexinitlen,
     50     const u_char *skexinit, size_t skexinitlen,
     51     const u_char *serverhostkeyblob, size_t sbloblen,
     52     int min, int wantbits, int max,
     53     const BIGNUM *prime,
     54     const BIGNUM *gen,
     55     const BIGNUM *client_dh_pub,
     56     const BIGNUM *server_dh_pub,
     57     const BIGNUM *shared_secret,
     58     u_char *hash, size_t *hashlen)
     59 {
     60 	struct sshbuf *b;
     61 	int r;
     62 
     63 	if (*hashlen < ssh_digest_bytes(SSH_DIGEST_SHA1))
     64 		return SSH_ERR_INVALID_ARGUMENT;
     65 	if ((b = sshbuf_new()) == NULL)
     66 		return SSH_ERR_ALLOC_FAIL;
     67 	if ((r = sshbuf_put_cstring(b, client_version_string)) != 0 ||
     68 	    (r = sshbuf_put_cstring(b, server_version_string)) != 0 ||
     69 	    /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
     70 	    (r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 ||
     71 	    (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
     72 	    (r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 ||
     73 	    (r = sshbuf_put_u32(b, skexinitlen+1)) != 0 ||
     74 	    (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
     75 	    (r = sshbuf_put(b, skexinit, skexinitlen)) != 0 ||
     76 	    (r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 ||
     77 	    (min != -1 && (r = sshbuf_put_u32(b, min)) != 0) ||
     78 	    (r = sshbuf_put_u32(b, wantbits)) != 0 ||
     79 	    (max != -1 && (r = sshbuf_put_u32(b, max)) != 0) ||
     80 	    (r = sshbuf_put_bignum2(b, prime)) != 0 ||
     81 	    (r = sshbuf_put_bignum2(b, gen)) != 0 ||
     82 	    (r = sshbuf_put_bignum2(b, client_dh_pub)) != 0 ||
     83 	    (r = sshbuf_put_bignum2(b, server_dh_pub)) != 0 ||
     84 	    (r = sshbuf_put_bignum2(b, shared_secret)) != 0) {
     85 		sshbuf_free(b);
     86 		return r;
     87 	}
     88 #ifdef DEBUG_KEXDH
     89 	sshbuf_dump(b, stderr);
     90 #endif
     91 	if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
     92 		sshbuf_free(b);
     93 		return SSH_ERR_LIBCRYPTO_ERROR;
     94 	}
     95 	sshbuf_free(b);
     96 	*hashlen = ssh_digest_bytes(hash_alg);
     97 #ifdef DEBUG_KEXDH
     98 	dump_digest("hash", hash, *hashlen);
     99 #endif
    100 	return 0;
    101 }
    102 #endif /* WITH_OPENSSL */
    103