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Annotation of src/usr.bin/ssh/kexdh.c, Revision 1.28

1.28    ! djm         1: /* $OpenBSD: kexdh.c,v 1.27 2018/12/27 03:25:25 djm Exp $ */
1.1       markus      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:
1.23      deraadt    26: #include <sys/types.h>
                     27:
                     28: #include <signal.h>
1.1       markus     29:
1.19      markus     30: #include <openssl/evp.h>
1.1       markus     31:
1.19      markus     32: #include "ssh2.h"
1.25      markus     33: #include "sshkey.h"
1.23      deraadt    34: #include "cipher.h"
1.1       markus     35: #include "kex.h"
1.28    ! djm        36: #include "dh.h"
1.25      markus     37: #include "ssherr.h"
                     38: #include "sshbuf.h"
1.24      djm        39: #include "digest.h"
1.28    ! djm        40:
        !            41: int
        !            42: kex_dh_keygen(struct kex *kex)
        !            43: {
        !            44:        switch (kex->kex_type) {
        !            45:        case KEX_DH_GRP1_SHA1:
        !            46:                kex->dh = dh_new_group1();
        !            47:                break;
        !            48:        case KEX_DH_GRP14_SHA1:
        !            49:        case KEX_DH_GRP14_SHA256:
        !            50:                kex->dh = dh_new_group14();
        !            51:                break;
        !            52:        case KEX_DH_GRP16_SHA512:
        !            53:                kex->dh = dh_new_group16();
        !            54:                break;
        !            55:        case KEX_DH_GRP18_SHA512:
        !            56:                kex->dh = dh_new_group18();
        !            57:                break;
        !            58:        default:
        !            59:                return SSH_ERR_INVALID_ARGUMENT;
        !            60:        }
        !            61:        if (kex->dh == NULL)
        !            62:                return SSH_ERR_ALLOC_FAIL;
        !            63:        return (dh_gen_key(kex->dh, kex->we_need * 8));
        !            64: }
1.1       markus     65:
1.25      markus     66: int
1.1       markus     67: kex_dh_hash(
1.26      djm        68:     int hash_alg,
1.27      djm        69:     const struct sshbuf *client_version,
                     70:     const struct sshbuf *server_version,
1.25      markus     71:     const u_char *ckexinit, size_t ckexinitlen,
                     72:     const u_char *skexinit, size_t skexinitlen,
                     73:     const u_char *serverhostkeyblob, size_t sbloblen,
                     74:     const BIGNUM *client_dh_pub,
                     75:     const BIGNUM *server_dh_pub,
                     76:     const BIGNUM *shared_secret,
                     77:     u_char *hash, size_t *hashlen)
1.1       markus     78: {
1.25      markus     79:        struct sshbuf *b;
                     80:        int r;
1.1       markus     81:
1.26      djm        82:        if (*hashlen < ssh_digest_bytes(hash_alg))
1.25      markus     83:                return SSH_ERR_INVALID_ARGUMENT;
                     84:        if ((b = sshbuf_new()) == NULL)
                     85:                return SSH_ERR_ALLOC_FAIL;
1.27      djm        86:        if ((r = sshbuf_put_stringb(b, client_version)) < 0 ||
                     87:            (r = sshbuf_put_stringb(b, server_version)) < 0 ||
1.25      markus     88:            /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
                     89:            (r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 ||
                     90:            (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
                     91:            (r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 ||
                     92:            (r = sshbuf_put_u32(b, skexinitlen+1)) != 0 ||
                     93:            (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
                     94:            (r = sshbuf_put(b, skexinit, skexinitlen)) != 0 ||
                     95:            (r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 ||
                     96:            (r = sshbuf_put_bignum2(b, client_dh_pub)) != 0 ||
                     97:            (r = sshbuf_put_bignum2(b, server_dh_pub)) != 0 ||
                     98:            (r = sshbuf_put_bignum2(b, shared_secret)) != 0) {
                     99:                sshbuf_free(b);
                    100:                return r;
                    101:        }
1.1       markus    102: #ifdef DEBUG_KEX
1.25      markus    103:        sshbuf_dump(b, stderr);
1.1       markus    104: #endif
1.26      djm       105:        if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
1.25      markus    106:                sshbuf_free(b);
                    107:                return SSH_ERR_LIBCRYPTO_ERROR;
                    108:        }
                    109:        sshbuf_free(b);
1.26      djm       110:        *hashlen = ssh_digest_bytes(hash_alg);
1.1       markus    111: #ifdef DEBUG_KEX
1.25      markus    112:        dump_digest("hash", hash, *hashlen);
1.1       markus    113: #endif
1.25      markus    114:        return 0;
1.1       markus    115: }