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Annotation of src/usr.bin/ssh/kexecdh.c, Revision 1.1

1.1     ! djm         1: /* $OpenBSD$ */
        !             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:
        !            49:        if (strlen(kexname) < sizeof(KEX_ECDH_SHA256) - 1)
        !            50:                fatal("%s: kexname too short \"%s\"", __func__, kexname);
        !            51:        ret = key_curve_name_to_nid(kexname + sizeof(KEX_ECDH_SHA256) - 1);
        !            52:        if (ret == -1)
        !            53:                fatal("%s: unsupported curve negotiated \"%s\"", __func__,
        !            54:                    kexname);
        !            55:        return ret;
        !            56: }
        !            57:
        !            58: void
        !            59: kex_ecdh_hash(
        !            60:     const EVP_MD *evp_md,
        !            61:     const EC_GROUP *ec_group,
        !            62:     char *client_version_string,
        !            63:     char *server_version_string,
        !            64:     char *ckexinit, int ckexinitlen,
        !            65:     char *skexinit, int skexinitlen,
        !            66:     u_char *serverhostkeyblob, int sbloblen,
        !            67:     const EC_POINT *client_dh_pub,
        !            68:     const EC_POINT *server_dh_pub,
        !            69:     const BIGNUM *shared_secret,
        !            70:     u_char **hash, u_int *hashlen)
        !            71: {
        !            72:        Buffer b;
        !            73:        EVP_MD_CTX md;
        !            74:        static u_char digest[EVP_MAX_MD_SIZE];
        !            75:
        !            76:        buffer_init(&b);
        !            77:        buffer_put_cstring(&b, client_version_string);
        !            78:        buffer_put_cstring(&b, server_version_string);
        !            79:
        !            80:        /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
        !            81:        buffer_put_int(&b, ckexinitlen+1);
        !            82:        buffer_put_char(&b, SSH2_MSG_KEXINIT);
        !            83:        buffer_append(&b, ckexinit, ckexinitlen);
        !            84:        buffer_put_int(&b, skexinitlen+1);
        !            85:        buffer_put_char(&b, SSH2_MSG_KEXINIT);
        !            86:        buffer_append(&b, skexinit, skexinitlen);
        !            87:
        !            88:        buffer_put_string(&b, serverhostkeyblob, sbloblen);
        !            89:        buffer_put_ecpoint(&b, ec_group, client_dh_pub);
        !            90:        buffer_put_ecpoint(&b, ec_group, server_dh_pub);
        !            91:        buffer_put_bignum2(&b, shared_secret);
        !            92:
        !            93: #ifdef DEBUG_KEX
        !            94:        buffer_dump(&b);
        !            95: #endif
        !            96:        EVP_DigestInit(&md, evp_md);
        !            97:        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
        !            98:        EVP_DigestFinal(&md, digest, NULL);
        !            99:
        !           100:        buffer_free(&b);
        !           101:
        !           102: #ifdef DEBUG_KEX
        !           103:        dump_digest("hash", digest, EVP_MD_size(evp_md));
        !           104: #endif
        !           105:        *hash = digest;
        !           106:        *hashlen = EVP_MD_size(evp_md);
        !           107: }
        !           108: