Return to kexecdh.c CVS log

Up to [local] / src / usr.bin / ssh

Annotation of src/usr.bin/ssh/kexecdh.c, Revision 1.2

1.2     ! djm         1: /* $OpenBSD: kexecdh.c,v 1.1 2010/08/31 11:54:45 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: int
                     45: kex_ecdh_name_to_nid(const char *kexname)
                     46: {
                     47:        int ret;
                     48:
1.2     ! djm        49:        if (strlen(kexname) < sizeof(KEX_ECDH_SHA2_STEM) - 1)
1.1       djm        50:                fatal("%s: kexname too short \"%s\"", __func__, kexname);
1.2     ! djm        51:        ret = key_curve_name_to_nid(kexname + sizeof(KEX_ECDH_SHA2_STEM) - 1);
1.1       djm        52:        if (ret == -1)
                     53:                fatal("%s: unsupported curve negotiated \"%s\"", __func__,
                     54:                    kexname);
                     55:        return ret;
1.2     ! djm        56: }
        !            57:
        !            58: const EVP_MD *
        !            59: kex_ecdh_name_to_evpmd(const char *kexname)
        !            60: {
        !            61:        int nid = kex_ecdh_name_to_nid(kexname);
        !            62:
        !            63:        return key_ec_nid_to_evpmd(nid);
1.1       djm        64: }
                     65:
                     66: void
                     67: kex_ecdh_hash(
                     68:     const EVP_MD *evp_md,
                     69:     const EC_GROUP *ec_group,
                     70:     char *client_version_string,
                     71:     char *server_version_string,
                     72:     char *ckexinit, int ckexinitlen,
                     73:     char *skexinit, int skexinitlen,
                     74:     u_char *serverhostkeyblob, int sbloblen,
                     75:     const EC_POINT *client_dh_pub,
                     76:     const EC_POINT *server_dh_pub,
                     77:     const BIGNUM *shared_secret,
                     78:     u_char **hash, u_int *hashlen)
                     79: {
                     80:        Buffer b;
                     81:        EVP_MD_CTX md;
                     82:        static u_char digest[EVP_MAX_MD_SIZE];
                     83:
                     84:        buffer_init(&b);
                     85:        buffer_put_cstring(&b, client_version_string);
                     86:        buffer_put_cstring(&b, server_version_string);
                     87:
                     88:        /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
                     89:        buffer_put_int(&b, ckexinitlen+1);
                     90:        buffer_put_char(&b, SSH2_MSG_KEXINIT);
                     91:        buffer_append(&b, ckexinit, ckexinitlen);
                     92:        buffer_put_int(&b, skexinitlen+1);
                     93:        buffer_put_char(&b, SSH2_MSG_KEXINIT);
                     94:        buffer_append(&b, skexinit, skexinitlen);
                     95:
                     96:        buffer_put_string(&b, serverhostkeyblob, sbloblen);
                     97:        buffer_put_ecpoint(&b, ec_group, client_dh_pub);
                     98:        buffer_put_ecpoint(&b, ec_group, server_dh_pub);
                     99:        buffer_put_bignum2(&b, shared_secret);
                    100:
                    101: #ifdef DEBUG_KEX
                    102:        buffer_dump(&b);
                    103: #endif
                    104:        EVP_DigestInit(&md, evp_md);
                    105:        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
                    106:        EVP_DigestFinal(&md, digest, NULL);
                    107:
                    108:        buffer_free(&b);
                    109:
                    110: #ifdef DEBUG_KEX
                    111:        dump_digest("hash", digest, EVP_MD_size(evp_md));
                    112: #endif
                    113:        *hash = digest;
                    114:        *hashlen = EVP_MD_size(evp_md);
                    115: }
                    116: