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/*
* 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,
enum signkey_type expect_keytype) {
unsigned int len, typelen;
char *keytype = NULL;
enum signkey_type buf_keytype;
TRACE(("enter buf_get_ed25519_pub_key"))
dropbear_assert(key != NULL);
/* consume and check the key string */
keytype = buf_getstring(buf, &typelen);
buf_keytype = signkey_type_from_name(keytype, typelen);
m_free(keytype);
if (buf_keytype != expect_keytype) {
TRACE(("leave buf_get_ed25519_pub_key: mismatch key type"))
return DROPBEAR_FAILURE;
}
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 */
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