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/*
* Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <openssl/crypto.h>
#include <openssl/core_numbers.h>
#include <openssl/core_names.h>
#include <openssl/dh.h>
#include <openssl/params.h>
#include "internal/provider_algs.h"
static OSSL_OP_keyexch_newctx_fn dh_newctx;
static OSSL_OP_keyexch_init_fn dh_init;
static OSSL_OP_keyexch_set_peer_fn dh_set_peer;
static OSSL_OP_keyexch_derive_fn dh_derive;
static OSSL_OP_keyexch_freectx_fn dh_freectx;
static OSSL_OP_keyexch_dupctx_fn dh_dupctx;
/*
* What's passed as an actual key is defined by the KEYMGMT interface.
* We happen to know that our KEYMGMT simply passes DH structures, so
* we use that here too.
*/
typedef struct {
DH *dh;
DH *dhpeer;
int pad;
} PROV_DH_CTX;
static void *dh_newctx(void *provctx)
{
return OPENSSL_zalloc(sizeof(PROV_DH_CTX));
}
static int dh_init(void *vpdhctx, void *vdh)
{
PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
DH_free(pdhctx->dh);
pdhctx->dh = vdh;
DH_up_ref(pdhctx->dh);
return pdhctx->dh != NULL;
}
static int dh_set_peer(void *vpdhctx, void *vdh)
{
PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
DH_free(pdhctx->dhpeer);
pdhctx->dhpeer = vdh;
DH_up_ref(pdhctx->dhpeer);
return pdhctx->dhpeer != NULL;
}
static int dh_derive(void *vpdhctx, unsigned char *key, size_t *keylen,
size_t outlen)
{
PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
int ret;
size_t dhsize;
const BIGNUM *pub_key = NULL;
/* TODO(3.0): Add errors to stack */
if (pdhctx->dh == NULL || pdhctx->dhpeer == NULL)
return 0;
dhsize = (size_t)DH_size(pdhctx->dh);
if (key == NULL) {
*keylen = dhsize;
return 1;
}
if (outlen < dhsize)
return 0;
DH_get0_key(pdhctx->dhpeer, &pub_key, NULL);
ret = (pdhctx->pad) ? DH_compute_key_padded(key, pub_key, pdhctx->dh)
: DH_compute_key(key, pub_key, pdhctx->dh);
if (ret <= 0)
return 0;
*keylen = ret;
return 1;
}
static void dh_freectx(void *vpdhctx)
{
PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
DH_free(pdhctx->dh);
DH_free(pdhctx->dhpeer);
OPENSSL_free(pdhctx);
}
static void *dh_dupctx(void *vpdhctx)
{
PROV_DH_CTX *srcctx = (PROV_DH_CTX *)vpdhctx;
PROV_DH_CTX *dstctx;
dstctx = OPENSSL_zalloc(sizeof(*srcctx));
*dstctx = *srcctx;
if (dstctx->dh != NULL && !DH_up_ref(dstctx->dh)) {
OPENSSL_free(dstctx);
return NULL;
}
if (dstctx->dhpeer != NULL && !DH_up_ref(dstctx->dhpeer)) {
DH_free(dstctx->dh);
OPENSSL_free(dstctx);
return NULL;
}
return dstctx;
}
static int dh_set_params(void *vpdhctx, const OSSL_PARAM params[])
{
PROV_DH_CTX *pdhctx = (PROV_DH_CTX *)vpdhctx;
const OSSL_PARAM *p;
int pad;
if (pdhctx == NULL || params == NULL)
return 0;
p = OSSL_PARAM_locate_const(params, OSSL_EXCHANGE_PARAM_PAD);
if (p == NULL || !OSSL_PARAM_get_int(p, &pad))
return 0;
pdhctx->pad = pad;
return 1;
}
const OSSL_DISPATCH dh_keyexch_functions[] = {
{ OSSL_FUNC_KEYEXCH_NEWCTX, (void (*)(void))dh_newctx },
{ OSSL_FUNC_KEYEXCH_INIT, (void (*)(void))dh_init },
{ OSSL_FUNC_KEYEXCH_DERIVE, (void (*)(void))dh_derive },
{ OSSL_FUNC_KEYEXCH_SET_PEER, (void (*)(void))dh_set_peer },
{ OSSL_FUNC_KEYEXCH_FREECTX, (void (*)(void))dh_freectx },
{ OSSL_FUNC_KEYEXCH_DUPCTX, (void (*)(void))dh_dupctx },
{ OSSL_FUNC_KEYEXCH_SET_PARAMS, (void (*)(void))dh_set_params },
{ 0, NULL }
};
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