- (djm) [kexc25519.c kexc25519c.c kexc25519s.c] Import missed files from

   KEX/curve25519 change

1 files changed, 127 insertions, 0 deletions

diff --git a/kexc25519.c b/kexc25519.c
new file mode 100644
index 00000000..348a7d50
--- /dev/null
+++ b/kexc25519.c
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+/* $OpenBSD: kexc25519.c,v 1.2 2013/11/02 22:02:14 markus Exp $ */
+/*
+ * Copyright (c) 2001, 2013 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 <signal.h>
+#include <string.h>
+
+#include <openssl/bn.h>
+#include <openssl/evp.h>
+
+#include "buffer.h"
+#include "ssh2.h"
+#include "key.h"
+#include "cipher.h"
+#include "kex.h"
+#include "log.h"
+
+extern int crypto_scalarmult_curve25519(u_char a[CURVE25519_SIZE],
+    const u_char b[CURVE25519_SIZE], const u_char c[CURVE25519_SIZE])
+	__attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
+	__attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)))
+	__attribute__((__bounded__(__minbytes__, 3, CURVE25519_SIZE)));
+
+void
+kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE])
+{
+	static const u_char basepoint[CURVE25519_SIZE] = {9};
+
+	arc4random_buf(key, CURVE25519_SIZE);
+	crypto_scalarmult_curve25519(pub, key, basepoint);
+}
+
+BIGNUM *
+kexc25519_shared_key(const u_char key[CURVE25519_SIZE],
+    const u_char pub[CURVE25519_SIZE])
+{
+	u_char shared_key[CURVE25519_SIZE];
+	BIGNUM *shared_secret;
+
+	crypto_scalarmult_curve25519(shared_key, key, pub);
+#ifdef DEBUG_KEXECDH
+	dump_digest("shared secret", shared_key, CURVE25519_SIZE);
+#endif
+	if ((shared_secret = BN_new()) == NULL)
+		fatal("%s: BN_new failed", __func__);
+	if (BN_bin2bn(shared_key, sizeof(shared_key), shared_secret) == NULL)
+		fatal("%s: BN_bin2bn failed", __func__);
+	memset(shared_key, 0, CURVE25519_SIZE);	/* XXX explicit_bzero() */
+	return (shared_secret);
+}
+
+void
+kex_c25519_hash(
+    const EVP_MD *evp_md,
+    char *client_version_string,
+    char *server_version_string,
+    char *ckexinit, int ckexinitlen,
+    char *skexinit, int skexinitlen,
+    u_char *serverhostkeyblob, int sbloblen,
+    const u_char client_dh_pub[CURVE25519_SIZE],
+    const u_char server_dh_pub[CURVE25519_SIZE],
+    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_string(&b, client_dh_pub, CURVE25519_SIZE);
+	buffer_put_string(&b, server_dh_pub, CURVE25519_SIZE);
+	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);
+}