--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ed25519.c	Fri Jun 26 21:07:34 2020 +0800
@@ -0,0 +1,182 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+/* Perform Ed25519 operations on data, including reading keys, signing and
+ * verification. */
+
+#include "includes.h"
+#include "dbutil.h"
+#include "buffer.h"
+#include "ssh.h"
+#include "curve25519.h"
+#include "ed25519.h"
+
+#if DROPBEAR_ED25519
+
+/* Load a public ed25519 key from a buffer, initialising the values.
+ * The key will have the same format as buf_put_ed25519_key.
+ * These should be freed with ed25519_key_free.
+ * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
+int buf_get_ed25519_pub_key(buffer *buf, dropbear_ed25519_key *key) {
+
+	unsigned int len;
+
+	TRACE(("enter buf_get_ed25519_pub_key"))
+	dropbear_assert(key != NULL);
+
+	buf_incrpos(buf, 4+SSH_SIGNKEY_ED25519_LEN); /* int + "ssh-ed25519" */
+
+	len = buf_getint(buf);
+	if (len != CURVE25519_LEN || buf->len - buf->pos < len) {
+		TRACE(("leave buf_get_ed25519_pub_key: failure"))
+		return DROPBEAR_FAILURE;
+	}
+
+	m_burn(key->priv, CURVE25519_LEN);
+	memcpy(key->pub, buf_getptr(buf, CURVE25519_LEN), CURVE25519_LEN);
+	buf_incrpos(buf, CURVE25519_LEN);
+
+	TRACE(("leave buf_get_ed25519_pub_key: success"))
+	return DROPBEAR_SUCCESS;
+}
+
+/* Same as buf_get_ed25519_pub_key, but reads private key at the end.
+ * Loads a public and private ed25519 key from a buffer
+ * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
+int buf_get_ed25519_priv_key(buffer *buf, dropbear_ed25519_key *key) {
+
+	unsigned int len;
+
+	TRACE(("enter buf_get_ed25519_priv_key"))
+	dropbear_assert(key != NULL);
+
+	buf_incrpos(buf, 4+SSH_SIGNKEY_ED25519_LEN); /* int + "ssh-ed25519" */
+
+	len = buf_getint(buf);
+	if (len != CURVE25519_LEN*2 || buf->len - buf->pos < len) {
+		TRACE(("leave buf_get_ed25519_priv_key: failure"))
+		return DROPBEAR_FAILURE;
+	}
+
+	memcpy(key->priv, buf_getptr(buf, CURVE25519_LEN), CURVE25519_LEN);
+	buf_incrpos(buf, CURVE25519_LEN);
+	memcpy(key->pub, buf_getptr(buf, CURVE25519_LEN), CURVE25519_LEN);
+	buf_incrpos(buf, CURVE25519_LEN);
+
+	TRACE(("leave buf_get_ed25519_priv_key: success"))
+	return DROPBEAR_SUCCESS;
+}
+
+/* Clear and free the memory used by a public or private key */
+void ed25519_key_free(dropbear_ed25519_key *key) {
+
+	TRACE2(("enter ed25519_key_free"))
+
+	if (key == NULL) {
+		TRACE2(("leave ed25519_key_free: key == NULL"))
+		return;
+	}
+	m_burn(key->priv, CURVE25519_LEN);
+	m_free(key);
+
+	TRACE2(("leave ed25519_key_free"))
+}
+
+/* Put the public ed25519 key into the buffer in the required format */
+void buf_put_ed25519_pub_key(buffer *buf, const dropbear_ed25519_key *key) {
+
+	TRACE(("enter buf_put_ed25519_pub_key"))
+	dropbear_assert(key != NULL);
+
+	buf_putstring(buf, SSH_SIGNKEY_ED25519, SSH_SIGNKEY_ED25519_LEN);
+	buf_putstring(buf, key->pub, CURVE25519_LEN);
+
+	TRACE(("leave buf_put_ed25519_pub_key"))
+}
+
+/* Put the public and private ed25519 key into the buffer in the required format */
+void buf_put_ed25519_priv_key(buffer *buf, const dropbear_ed25519_key *key) {
+
+	TRACE(("enter buf_put_ed25519_priv_key"))
+	dropbear_assert(key != NULL);
+
+	buf_putstring(buf, SSH_SIGNKEY_ED25519, SSH_SIGNKEY_ED25519_LEN);
+	buf_putint(buf, CURVE25519_LEN*2);
+	buf_putbytes(buf, key->priv, CURVE25519_LEN);
+	buf_putbytes(buf, key->pub, CURVE25519_LEN);
+
+	TRACE(("leave buf_put_ed25519_priv_key"))
+}
+
+/* Sign the data presented with key, writing the signature contents
+ * to the buffer */
+void buf_put_ed25519_sign(buffer* buf, const dropbear_ed25519_key *key, const buffer *data_buf) {
+
+	unsigned char s[64];
+	unsigned long slen = sizeof(s);
+
+	TRACE(("enter buf_put_ed25519_sign"))
+	dropbear_assert(key != NULL);
+
+	dropbear_ed25519_sign(data_buf->data, data_buf->len, s, &slen, key->priv, key->pub);
+	buf_putstring(buf, SSH_SIGNKEY_ED25519, SSH_SIGNKEY_ED25519_LEN);
+	buf_putstring(buf, s, slen);
+
+	TRACE(("leave buf_put_ed25519_sign"))
+}
+
+#if DROPBEAR_SIGNKEY_VERIFY
+/* Verify a signature in buf, made on data by the key given.
+ * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
+int buf_ed25519_verify(buffer *buf, const dropbear_ed25519_key *key, const buffer *data_buf) {
+
+	int ret = DROPBEAR_FAILURE;
+	unsigned char *s;
+	unsigned long slen;
+
+	TRACE(("enter buf_ed25519_verify"))
+	dropbear_assert(key != NULL);
+
+	slen = buf_getint(buf);
+	if (slen != 64 || buf->len - buf->pos < slen) {
+		TRACE(("leave buf_ed25519_verify: bad size"))
+		goto out;
+	}
+	s = buf_getptr(buf, slen);
+
+	if (dropbear_ed25519_verify(data_buf->data, data_buf->len,
+				    s, slen, key->pub) == 0) {
+		/* signature is valid */
+		TRACE(("leave buf_ed25519_verify: success!"))
+		ret = DROPBEAR_SUCCESS;
+	}
+
+out:
+	TRACE(("leave buf_ed25519_verify: ret %d", ret))
+	return ret;
+}
+
+#endif /* DROPBEAR_SIGNKEY_VERIFY */
+
+#endif /* DROPBEAR_ED25519 */