325 lines
6.3 KiB
C
Executable File
325 lines
6.3 KiB
C
Executable File
/* $OpenBSD: tls13_key_share.c,v 1.6 2020/04/18 14:07:56 jsing Exp $ */
|
|
/*
|
|
* Copyright (c) 2020 Joel Sing <jsing@openbsd.org>
|
|
*
|
|
* Permission to use, copy, modify, and distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
|
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
|
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
|
|
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
|
|
#include <openssl/curve25519.h>
|
|
|
|
#include "bytestring.h"
|
|
#include "ssl_locl.h"
|
|
#include "tls13_internal.h"
|
|
|
|
struct tls13_key_share {
|
|
int nid;
|
|
uint16_t group_id;
|
|
|
|
EC_KEY *ecdhe;
|
|
EC_KEY *ecdhe_peer;
|
|
|
|
uint8_t *x25519_public;
|
|
uint8_t *x25519_private;
|
|
uint8_t *x25519_peer_public;
|
|
};
|
|
|
|
struct tls13_key_share *
|
|
tls13_key_share_new(uint16_t group_id)
|
|
{
|
|
struct tls13_key_share *ks;
|
|
int nid;
|
|
|
|
if ((nid = tls1_ec_curve_id2nid(group_id)) == 0)
|
|
return NULL;
|
|
|
|
if ((ks = calloc(1, sizeof(struct tls13_key_share))) == NULL)
|
|
return NULL;
|
|
|
|
ks->group_id = group_id;
|
|
ks->nid = nid;
|
|
|
|
return ks;
|
|
}
|
|
|
|
struct tls13_key_share *
|
|
tls13_key_share_new_nid(int nid)
|
|
{
|
|
uint16_t group_id;
|
|
|
|
if ((group_id = tls1_ec_nid2curve_id(nid)) == 0)
|
|
return NULL;
|
|
|
|
return tls13_key_share_new(group_id);
|
|
}
|
|
|
|
void
|
|
tls13_key_share_free(struct tls13_key_share *ks)
|
|
{
|
|
if (ks == NULL)
|
|
return;
|
|
|
|
EC_KEY_free(ks->ecdhe);
|
|
EC_KEY_free(ks->ecdhe_peer);
|
|
|
|
freezero(ks->x25519_public, X25519_KEY_LENGTH);
|
|
freezero(ks->x25519_private, X25519_KEY_LENGTH);
|
|
freezero(ks->x25519_peer_public, X25519_KEY_LENGTH);
|
|
|
|
freezero(ks, sizeof(*ks));
|
|
}
|
|
|
|
uint16_t
|
|
tls13_key_share_group(struct tls13_key_share *ks)
|
|
{
|
|
return ks->group_id;
|
|
}
|
|
|
|
int
|
|
tls13_key_share_peer_pkey(struct tls13_key_share *ks, EVP_PKEY *pkey)
|
|
{
|
|
if (ks->nid == NID_X25519 && ks->x25519_peer_public != NULL) {
|
|
if (!ssl_kex_dummy_ecdhe_x25519(pkey))
|
|
return 0;
|
|
} else if (ks->ecdhe_peer != NULL) {
|
|
if (!EVP_PKEY_set1_EC_KEY(pkey, ks->ecdhe_peer))
|
|
return 0;
|
|
} else {
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
tls13_key_share_generate_ecdhe_ecp(struct tls13_key_share *ks)
|
|
{
|
|
EC_KEY *ecdhe = NULL;
|
|
int ret = 0;
|
|
|
|
if (ks->ecdhe != NULL)
|
|
goto err;
|
|
|
|
if ((ecdhe = EC_KEY_new()) == NULL)
|
|
goto err;
|
|
if (!ssl_kex_generate_ecdhe_ecp(ecdhe, ks->nid))
|
|
goto err;
|
|
|
|
ks->ecdhe = ecdhe;
|
|
ecdhe = NULL;
|
|
|
|
ret = 1;
|
|
|
|
err:
|
|
EC_KEY_free(ecdhe);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
tls13_key_share_generate_x25519(struct tls13_key_share *ks)
|
|
{
|
|
uint8_t *public = NULL, *private = NULL;
|
|
int ret = 0;
|
|
|
|
if (ks->x25519_public != NULL || ks->x25519_private != NULL)
|
|
goto err;
|
|
|
|
if ((public = calloc(1, X25519_KEY_LENGTH)) == NULL)
|
|
goto err;
|
|
if ((private = calloc(1, X25519_KEY_LENGTH)) == NULL)
|
|
goto err;
|
|
|
|
X25519_keypair(public, private);
|
|
|
|
ks->x25519_public = public;
|
|
ks->x25519_private = private;
|
|
public = NULL;
|
|
private = NULL;
|
|
|
|
ret = 1;
|
|
|
|
err:
|
|
freezero(public, X25519_KEY_LENGTH);
|
|
freezero(private, X25519_KEY_LENGTH);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int
|
|
tls13_key_share_generate(struct tls13_key_share *ks)
|
|
{
|
|
if (ks->nid == NID_X25519)
|
|
return tls13_key_share_generate_x25519(ks);
|
|
|
|
return tls13_key_share_generate_ecdhe_ecp(ks);
|
|
}
|
|
|
|
static int
|
|
tls13_key_share_public_ecdhe_ecp(struct tls13_key_share *ks, CBB *cbb)
|
|
{
|
|
if (ks->ecdhe == NULL)
|
|
return 0;
|
|
|
|
return ssl_kex_public_ecdhe_ecp(ks->ecdhe, cbb);
|
|
}
|
|
|
|
static int
|
|
tls13_key_share_public_x25519(struct tls13_key_share *ks, CBB *cbb)
|
|
{
|
|
if (ks->x25519_public == NULL)
|
|
return 0;
|
|
|
|
return CBB_add_bytes(cbb, ks->x25519_public, X25519_KEY_LENGTH);
|
|
}
|
|
|
|
int
|
|
tls13_key_share_public(struct tls13_key_share *ks, CBB *cbb)
|
|
{
|
|
CBB key_exchange;
|
|
|
|
if (!CBB_add_u16(cbb, ks->group_id))
|
|
goto err;
|
|
if (!CBB_add_u16_length_prefixed(cbb, &key_exchange))
|
|
goto err;
|
|
|
|
if (ks->nid == NID_X25519) {
|
|
if (!tls13_key_share_public_x25519(ks, &key_exchange))
|
|
goto err;
|
|
} else {
|
|
if (!tls13_key_share_public_ecdhe_ecp(ks, &key_exchange))
|
|
goto err;
|
|
}
|
|
|
|
if (!CBB_flush(cbb))
|
|
goto err;
|
|
|
|
return 1;
|
|
|
|
err:
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
tls13_key_share_peer_public_ecdhe_ecp(struct tls13_key_share *ks, CBS *cbs)
|
|
{
|
|
EC_KEY *ecdhe = NULL;
|
|
int ret = 0;
|
|
|
|
if (ks->ecdhe_peer != NULL)
|
|
goto err;
|
|
|
|
if ((ecdhe = EC_KEY_new()) == NULL)
|
|
goto err;
|
|
if (!ssl_kex_peer_public_ecdhe_ecp(ecdhe, ks->nid, cbs))
|
|
goto err;
|
|
|
|
ks->ecdhe_peer = ecdhe;
|
|
ecdhe = NULL;
|
|
|
|
ret = 1;
|
|
|
|
err:
|
|
EC_KEY_free(ecdhe);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
tls13_key_share_peer_public_x25519(struct tls13_key_share *ks, CBS *cbs)
|
|
{
|
|
size_t out_len;
|
|
|
|
if (ks->x25519_peer_public != NULL)
|
|
return 0;
|
|
|
|
if (CBS_len(cbs) != X25519_KEY_LENGTH)
|
|
return 0;
|
|
|
|
return CBS_stow(cbs, &ks->x25519_peer_public, &out_len);
|
|
}
|
|
|
|
int
|
|
tls13_key_share_peer_public(struct tls13_key_share *ks, uint16_t group,
|
|
CBS *cbs)
|
|
{
|
|
if (ks->group_id != group)
|
|
return 0;
|
|
|
|
if (ks->nid == NID_X25519) {
|
|
if (!tls13_key_share_peer_public_x25519(ks, cbs))
|
|
return 0;
|
|
} else {
|
|
if (!tls13_key_share_peer_public_ecdhe_ecp(ks, cbs))
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
tls13_key_share_derive_ecdhe_ecp(struct tls13_key_share *ks,
|
|
uint8_t **shared_key, size_t *shared_key_len)
|
|
{
|
|
if (ks->ecdhe == NULL || ks->ecdhe_peer == NULL)
|
|
return 0;
|
|
|
|
return ssl_kex_derive_ecdhe_ecp(ks->ecdhe, ks->ecdhe_peer,
|
|
shared_key, shared_key_len);
|
|
}
|
|
|
|
static int
|
|
tls13_key_share_derive_x25519(struct tls13_key_share *ks,
|
|
uint8_t **shared_key, size_t *shared_key_len)
|
|
{
|
|
uint8_t *sk = NULL;
|
|
int ret = 0;
|
|
|
|
if (ks->x25519_private == NULL || ks->x25519_peer_public == NULL)
|
|
goto err;
|
|
|
|
if ((sk = calloc(1, X25519_KEY_LENGTH)) == NULL)
|
|
goto err;
|
|
if (!X25519(sk, ks->x25519_private, ks->x25519_peer_public))
|
|
goto err;
|
|
|
|
*shared_key = sk;
|
|
*shared_key_len = X25519_KEY_LENGTH;
|
|
sk = NULL;
|
|
|
|
ret = 1;
|
|
|
|
err:
|
|
freezero(sk, X25519_KEY_LENGTH);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int
|
|
tls13_key_share_derive(struct tls13_key_share *ks, uint8_t **shared_key,
|
|
size_t *shared_key_len)
|
|
{
|
|
if (*shared_key != NULL)
|
|
return 0;
|
|
|
|
*shared_key_len = 0;
|
|
|
|
if (ks->nid == NID_X25519)
|
|
return tls13_key_share_derive_x25519(ks, shared_key,
|
|
shared_key_len);
|
|
|
|
return tls13_key_share_derive_ecdhe_ecp(ks, shared_key,
|
|
shared_key_len);
|
|
}
|