1 files changed, 129 insertions, 0 deletions

diff --git a/kexc25519c.c b/kexc25519c.c
new file mode 100644
index 000000000..a80678af6
--- /dev/null
+++ b/kexc25519c.c
@@ -0,0 +1,129 @@
+/* $OpenBSD: kexc25519c.c,v 1.4 2014/01/12 08:13:13 djm Exp $ */
+/*
+ * Copyright (c) 2001 Markus Friedl.  All rights reserved.
+ * Copyright (c) 2010 Damien Miller.  All rights reserved.
+ * Copyright (c) 2013 Aris Adamantiadis.  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 "includes.h"
+
+#include <sys/types.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+
+#include "xmalloc.h"
+#include "buffer.h"
+#include "key.h"
+#include "cipher.h"
+#include "kex.h"
+#include "log.h"
+#include "packet.h"
+#include "ssh2.h"
+
+void
+kexc25519_client(Kex *kex)
+{
+        Key *server_host_key;
+        u_char client_key[CURVE25519_SIZE];
+        u_char client_pubkey[CURVE25519_SIZE];
+        u_char *server_pubkey = NULL;
+        u_char *server_host_key_blob = NULL, *signature = NULL;
+        u_char *hash;
+        u_int slen, sbloblen, hashlen;
+        Buffer shared_secret;
+
+        kexc25519_keygen(client_key, client_pubkey);
+
+        packet_start(SSH2_MSG_KEX_ECDH_INIT);
+        packet_put_string(client_pubkey, sizeof(client_pubkey));
+        packet_send();
+        debug("sending SSH2_MSG_KEX_ECDH_INIT");
+
+#ifdef DEBUG_KEXECDH
+        dump_digest("client private key:", client_key, sizeof(client_key));
+#endif
+
+        debug("expecting SSH2_MSG_KEX_ECDH_REPLY");
+        packet_read_expect(SSH2_MSG_KEX_ECDH_REPLY);
+
+        /* hostkey */
+        server_host_key_blob = packet_get_string(&sbloblen);
+        server_host_key = key_from_blob(server_host_key_blob, sbloblen);
+        if (server_host_key == NULL)
+                fatal("cannot decode server_host_key_blob");
+        if (server_host_key->type != kex->hostkey_type)
+                fatal("type mismatch for decoded server_host_key_blob");
+        if (kex->verify_host_key == NULL)
+                fatal("cannot verify server_host_key");
+        if (kex->verify_host_key(server_host_key) == -1)
+                fatal("server_host_key verification failed");
+
+        /* Q_S, server public key */
+        server_pubkey = packet_get_string(&slen);
+        if (slen != CURVE25519_SIZE)
+                fatal("Incorrect size for server Curve25519 pubkey: %d", slen);
+
+#ifdef DEBUG_KEXECDH
+        dump_digest("server public key:", server_pubkey, CURVE25519_SIZE);
+#endif
+
+        /* signed H */
+        signature = packet_get_string(&slen);
+        packet_check_eom();
+
+        buffer_init(&shared_secret);
+        kexc25519_shared_key(client_key, server_pubkey, &shared_secret);
+
+        /* calc and verify H */
+        kex_c25519_hash(
+            kex->hash_alg,
+            kex->client_version_string,
+            kex->server_version_string,
+            buffer_ptr(&kex->my), buffer_len(&kex->my),
+            buffer_ptr(&kex->peer), buffer_len(&kex->peer),
+            server_host_key_blob, sbloblen,
+            client_pubkey,
+            server_pubkey,
+            buffer_ptr(&shared_secret), buffer_len(&shared_secret),
+            &hash, &hashlen
+        );
+        free(server_host_key_blob);
+        free(server_pubkey);
+        if (key_verify(server_host_key, signature, slen, hash, hashlen) != 1)
+                fatal("key_verify failed for server_host_key");
+        key_free(server_host_key);
+        free(signature);
+
+        /* save session id */
+        if (kex->session_id == NULL) {
+                kex->session_id_len = hashlen;
+                kex->session_id = xmalloc(kex->session_id_len);
+                memcpy(kex->session_id, hash, kex->session_id_len);
+        }
+        kex_derive_keys(kex, hash, hashlen,
+            buffer_ptr(&shared_secret), buffer_len(&shared_secret));
+        buffer_free(&shared_secret);
+        kex_finish(kex);
+}