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Diffstat (limited to 'kexecdh.c')
| -rw-r--r-- | kexecdh.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/kexecdh.c b/kexecdh.c new file mode 100644 index 00000000..a5a14f4b --- /dev/null +++ b/kexecdh.c @@ -0,0 +1,108 @@ +/* $OpenBSD: kexecdh.c,v 1.1 2010/08/31 11:54:45 djm Exp $ */ +/* + * Copyright (c) 2001 Markus Friedl. All rights reserved. + * Copyright (c) 2010 Damien Miller. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/types.h> + +#include <signal.h> +#include <string.h> + +#include <openssl/bn.h> +#include <openssl/evp.h> +#include <openssl/ec.h> +#include <openssl/ecdh.h> + +#include "buffer.h" +#include "ssh2.h" +#include "key.h" +#include "cipher.h" +#include "kex.h" +#include "log.h" + +int +kex_ecdh_name_to_nid(const char *kexname) +{ + int ret; + + if (strlen(kexname) < sizeof(KEX_ECDH_SHA256) - 1) + fatal("%s: kexname too short \"%s\"", __func__, kexname); + ret = key_curve_name_to_nid(kexname + sizeof(KEX_ECDH_SHA256) - 1); + if (ret == -1) + fatal("%s: unsupported curve negotiated \"%s\"", __func__, + kexname); + return ret; +} + +void +kex_ecdh_hash( + const EVP_MD *evp_md, + const EC_GROUP *ec_group, + char *client_version_string, + char *server_version_string, + char *ckexinit, int ckexinitlen, + char *skexinit, int skexinitlen, + u_char *serverhostkeyblob, int sbloblen, + const EC_POINT *client_dh_pub, + const EC_POINT *server_dh_pub, + const BIGNUM *shared_secret, + u_char **hash, u_int *hashlen) +{ + Buffer b; + EVP_MD_CTX md; + static u_char digest[EVP_MAX_MD_SIZE]; + + buffer_init(&b); + buffer_put_cstring(&b, client_version_string); + buffer_put_cstring(&b, server_version_string); + + /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ + buffer_put_int(&b, ckexinitlen+1); + buffer_put_char(&b, SSH2_MSG_KEXINIT); + buffer_append(&b, ckexinit, ckexinitlen); + buffer_put_int(&b, skexinitlen+1); + buffer_put_char(&b, SSH2_MSG_KEXINIT); + buffer_append(&b, skexinit, skexinitlen); + + buffer_put_string(&b, serverhostkeyblob, sbloblen); + buffer_put_ecpoint(&b, ec_group, client_dh_pub); + buffer_put_ecpoint(&b, ec_group, server_dh_pub); + buffer_put_bignum2(&b, shared_secret); + +#ifdef DEBUG_KEX + buffer_dump(&b); +#endif + EVP_DigestInit(&md, evp_md); + EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); + EVP_DigestFinal(&md, digest, NULL); + + buffer_free(&b); + +#ifdef DEBUG_KEX + dump_digest("hash", digest, EVP_MD_size(evp_md)); +#endif + *hash = digest; + *hashlen = EVP_MD_size(evp_md); +} + |