exchange.c
/*
* Copyright 2019-2020 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/evp.h>
#include <openssl/err.h>
#include "internal/refcount.h"
#include "crypto/evp.h"
#include "internal/provider.h"
#include "internal/numbers.h" /* includes SIZE_MAX */
#include "evp_local.h"
static EVP_KEYEXCH *evp_keyexch_new(OSSL_PROVIDER *prov)
{
EVP_KEYEXCH *exchange = OPENSSL_zalloc(sizeof(EVP_KEYEXCH));
if (exchange == NULL) {
ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
return NULL;
}
exchange->lock = CRYPTO_THREAD_lock_new();
if (exchange->lock == NULL) {
ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
OPENSSL_free(exchange);
return NULL;
}
exchange->prov = prov;
ossl_provider_up_ref(prov);
exchange->refcnt = 1;
return exchange;
}
static void *evp_keyexch_from_dispatch(int name_id,
const OSSL_DISPATCH *fns,
OSSL_PROVIDER *prov)
{
EVP_KEYEXCH *exchange = NULL;
int fncnt = 0, sparamfncnt = 0, gparamfncnt = 0;
if ((exchange = evp_keyexch_new(prov)) == NULL) {
ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
goto err;
}
exchange->name_id = name_id;
for (; fns->function_id != 0; fns++) {
switch (fns->function_id) {
case OSSL_FUNC_KEYEXCH_NEWCTX:
if (exchange->newctx != NULL)
break;
exchange->newctx = OSSL_FUNC_keyexch_newctx(fns);
fncnt++;
break;
case OSSL_FUNC_KEYEXCH_INIT:
if (exchange->init != NULL)
break;
exchange->init = OSSL_FUNC_keyexch_init(fns);
fncnt++;
break;
case OSSL_FUNC_KEYEXCH_SET_PEER:
if (exchange->set_peer != NULL)
break;
exchange->set_peer = OSSL_FUNC_keyexch_set_peer(fns);
break;
case OSSL_FUNC_KEYEXCH_DERIVE:
if (exchange->derive != NULL)
break;
exchange->derive = OSSL_FUNC_keyexch_derive(fns);
fncnt++;
break;
case OSSL_FUNC_KEYEXCH_FREECTX:
if (exchange->freectx != NULL)
break;
exchange->freectx = OSSL_FUNC_keyexch_freectx(fns);
fncnt++;
break;
case OSSL_FUNC_KEYEXCH_DUPCTX:
if (exchange->dupctx != NULL)
break;
exchange->dupctx = OSSL_FUNC_keyexch_dupctx(fns);
break;
case OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS:
if (exchange->get_ctx_params != NULL)
break;
exchange->get_ctx_params = OSSL_FUNC_keyexch_get_ctx_params(fns);
gparamfncnt++;
break;
case OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS:
if (exchange->gettable_ctx_params != NULL)
break;
exchange->gettable_ctx_params
= OSSL_FUNC_keyexch_gettable_ctx_params(fns);
gparamfncnt++;
break;
case OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS:
if (exchange->set_ctx_params != NULL)
break;
exchange->set_ctx_params = OSSL_FUNC_keyexch_set_ctx_params(fns);
sparamfncnt++;
break;
case OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS:
if (exchange->settable_ctx_params != NULL)
break;
exchange->settable_ctx_params
= OSSL_FUNC_keyexch_settable_ctx_params(fns);
sparamfncnt++;
break;
}
}
if (fncnt != 4
|| (gparamfncnt != 0 && gparamfncnt != 2)
|| (sparamfncnt != 0 && sparamfncnt != 2)) {
/*
* In order to be a consistent set of functions we must have at least
* a complete set of "exchange" functions: init, derive, newctx,
* and freectx. The set_ctx_params and settable_ctx_params functions are
* optional, but if one of them is present then the other one must also
* be present. Same goes for get_ctx_params and gettable_ctx_params.
* The dupctx and set_peer functions are optional.
*/
EVPerr(EVP_F_EVP_KEYEXCH_FROM_DISPATCH,
EVP_R_INVALID_PROVIDER_FUNCTIONS);
goto err;
}
return exchange;
err:
EVP_KEYEXCH_free(exchange);
return NULL;
}
void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange)
{
if (exchange != NULL) {
int i;
CRYPTO_DOWN_REF(&exchange->refcnt, &i, exchange->lock);
if (i > 0)
return;
ossl_provider_free(exchange->prov);
CRYPTO_THREAD_lock_free(exchange->lock);
OPENSSL_free(exchange);
}
}
int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange)
{
int ref = 0;
CRYPTO_UP_REF(&exchange->refcnt, &ref, exchange->lock);
return 1;
}
OSSL_PROVIDER *EVP_KEYEXCH_provider(const EVP_KEYEXCH *exchange)
{
return exchange->prov;
}
EVP_KEYEXCH *EVP_KEYEXCH_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
const char *properties)
{
return evp_generic_fetch(ctx, OSSL_OP_KEYEXCH, algorithm, properties,
evp_keyexch_from_dispatch,
(int (*)(void *))EVP_KEYEXCH_up_ref,
(void (*)(void *))EVP_KEYEXCH_free);
}
int EVP_PKEY_derive_init(EVP_PKEY_CTX *ctx)
{
int ret;
void *provkey = NULL;
EVP_KEYEXCH *exchange = NULL;
EVP_KEYMGMT *tmp_keymgmt = NULL;
const char *supported_exch = NULL;
if (ctx == NULL) {
EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
return -2;
}
evp_pkey_ctx_free_old_ops(ctx);
ctx->operation = EVP_PKEY_OP_DERIVE;
/*
* TODO when we stop falling back to legacy, this and the ERR_pop_to_mark()
* calls can be removed.
*/
ERR_set_mark();
if (evp_pkey_ctx_is_legacy(ctx))
goto legacy;
/*
* Ensure that the key is provided, either natively, or as a cached export.
* If not, goto legacy
*/
tmp_keymgmt = ctx->keymgmt;
if (ctx->pkey == NULL) {
/*
* Some algorithms (e.g. legacy KDFs) don't have a pkey - so we create
* a blank one.
*/
EVP_PKEY *pkey = EVP_PKEY_new();
if (pkey == NULL || !EVP_PKEY_set_type_by_keymgmt(pkey, tmp_keymgmt)) {
ERR_clear_last_mark();
EVP_PKEY_free(pkey);
ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
goto err;
}
provkey = pkey->keydata = evp_keymgmt_newdata(tmp_keymgmt);
if (provkey == NULL)
EVP_PKEY_free(pkey);
else
ctx->pkey = pkey;
} else {
provkey = evp_pkey_export_to_provider(ctx->pkey, ctx->libctx,
&tmp_keymgmt, ctx->propquery);
}
if (provkey == NULL)
goto legacy;
if (!EVP_KEYMGMT_up_ref(tmp_keymgmt)) {
ERR_clear_last_mark();
ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);
goto err;
}
EVP_KEYMGMT_free(ctx->keymgmt);
ctx->keymgmt = tmp_keymgmt;
if (ctx->keymgmt->query_operation_name != NULL)
supported_exch = ctx->keymgmt->query_operation_name(OSSL_OP_KEYEXCH);
/*
* If we didn't get a supported exch, assume there is one with the
* same name as the key type.
*/
if (supported_exch == NULL)
supported_exch = ctx->keytype;
/*
* Because we cleared out old ops, we shouldn't need to worry about
* checking if exchange is already there.
*/
exchange = EVP_KEYEXCH_fetch(ctx->libctx, supported_exch, ctx->propquery);
if (exchange == NULL
|| (EVP_KEYMGMT_provider(ctx->keymgmt)
!= EVP_KEYEXCH_provider(exchange))) {
/*
* We don't need to free ctx->keymgmt here, as it's not necessarily
* tied to this operation. It will be freed by EVP_PKEY_CTX_free().
*/
EVP_KEYEXCH_free(exchange);
goto legacy;
}
/*
* TODO remove this when legacy is gone
* If we don't have the full support we need with provided methods,
* let's go see if legacy does.
*/
ERR_pop_to_mark();
/* No more legacy from here down to legacy: */
ctx->op.kex.exchange = exchange;
ctx->op.kex.exchprovctx = exchange->newctx(ossl_provider_ctx(exchange->prov));
if (ctx->op.kex.exchprovctx == NULL) {
/* The provider key can stay in the cache */
EVPerr(0, EVP_R_INITIALIZATION_ERROR);
goto err;
}
ret = exchange->init(ctx->op.kex.exchprovctx, provkey);
return ret ? 1 : 0;
err:
evp_pkey_ctx_free_old_ops(ctx);
ctx->operation = EVP_PKEY_OP_UNDEFINED;
return 0;
legacy:
/*
* TODO remove this when legacy is gone
* If we don't have the full support we need with provided methods,
* let's go see if legacy does.
*/
ERR_pop_to_mark();
#ifdef FIPS_MODULE
return 0;
#else
if (ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
EVPerr(0, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
return -2;
}
if (ctx->pmeth->derive_init == NULL)
return 1;
ret = ctx->pmeth->derive_init(ctx);
if (ret <= 0)
ctx->operation = EVP_PKEY_OP_UNDEFINED;
return ret;
#endif
}
int EVP_PKEY_derive_set_peer(EVP_PKEY_CTX *ctx, EVP_PKEY *peer)
{
int ret = 0;
void *provkey = NULL;
if (ctx == NULL) {
EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
return -2;
}
if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx) || ctx->op.kex.exchprovctx == NULL)
goto legacy;
if (ctx->op.kex.exchange->set_peer == NULL) {
EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
return -2;
}
provkey = evp_pkey_export_to_provider(peer, ctx->libctx, &ctx->keymgmt,
ctx->propquery);
/*
* If making the key provided wasn't possible, legacy may be able to pick
* it up
*/
if (provkey == NULL)
goto legacy;
return ctx->op.kex.exchange->set_peer(ctx->op.kex.exchprovctx, provkey);
legacy:
#ifdef FIPS_MODULE
return ret;
#else
/*
* TODO(3.0) investigate the case where the operation is deemed legacy,
* but the given peer key is provider only.
*/
if (ctx->pmeth == NULL
|| !(ctx->pmeth->derive != NULL
|| ctx->pmeth->encrypt != NULL
|| ctx->pmeth->decrypt != NULL)
|| ctx->pmeth->ctrl == NULL) {
EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
return -2;
}
if (ctx->operation != EVP_PKEY_OP_DERIVE
&& ctx->operation != EVP_PKEY_OP_ENCRYPT
&& ctx->operation != EVP_PKEY_OP_DECRYPT) {
EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER,
EVP_R_OPERATON_NOT_INITIALIZED);
return -1;
}
ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 0, peer);
if (ret <= 0)
return ret;
if (ret == 2)
return 1;
if (ctx->pkey == NULL) {
EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_NO_KEY_SET);
return -1;
}
if (ctx->pkey->type != peer->type) {
EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_KEY_TYPES);
return -1;
}
/*
* For clarity. The error is if parameters in peer are
* present (!missing) but don't match. EVP_PKEY_parameters_eq may return
* 1 (match), 0 (don't match) and -2 (comparison is not defined). -1
* (different key types) is impossible here because it is checked earlier.
* -2 is OK for us here, as well as 1, so we can check for 0 only.
*/
if (!EVP_PKEY_missing_parameters(peer) &&
!EVP_PKEY_parameters_eq(ctx->pkey, peer)) {
EVPerr(EVP_F_EVP_PKEY_DERIVE_SET_PEER, EVP_R_DIFFERENT_PARAMETERS);
return -1;
}
EVP_PKEY_free(ctx->peerkey);
ctx->peerkey = peer;
ret = ctx->pmeth->ctrl(ctx, EVP_PKEY_CTRL_PEER_KEY, 1, peer);
if (ret <= 0) {
ctx->peerkey = NULL;
return ret;
}
EVP_PKEY_up_ref(peer);
return 1;
#endif
}
int EVP_PKEY_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *pkeylen)
{
int ret;
if (ctx == NULL) {
EVPerr(EVP_F_EVP_PKEY_DERIVE,
EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
return -2;
}
if (!EVP_PKEY_CTX_IS_DERIVE_OP(ctx)) {
EVPerr(EVP_F_EVP_PKEY_DERIVE, EVP_R_OPERATON_NOT_INITIALIZED);
return -1;
}
if (ctx->op.kex.exchprovctx == NULL)
goto legacy;
ret = ctx->op.kex.exchange->derive(ctx->op.kex.exchprovctx, key, pkeylen,
SIZE_MAX);
return ret;
legacy:
if (ctx == NULL || ctx->pmeth == NULL || ctx->pmeth->derive == NULL) {
EVPerr(EVP_F_EVP_PKEY_DERIVE,
EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);
return -2;
}
M_check_autoarg(ctx, key, pkeylen, EVP_F_EVP_PKEY_DERIVE)
return ctx->pmeth->derive(ctx, key, pkeylen);
}
int EVP_KEYEXCH_number(const EVP_KEYEXCH *keyexch)
{
return keyexch->name_id;
}
int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *keyexch, const char *name)
{
return evp_is_a(keyexch->prov, keyexch->name_id, NULL, name);
}
void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
void (*fn)(EVP_KEYEXCH *keyexch, void *arg),
void *arg)
{
evp_generic_do_all(libctx, OSSL_OP_KEYEXCH,
(void (*)(void *, void *))fn, arg,
evp_keyexch_from_dispatch,
(void (*)(void *))EVP_KEYEXCH_free);
}
void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *keyexch,
void (*fn)(const char *name, void *data),
void *data)
{
if (keyexch->prov != NULL)
evp_names_do_all(keyexch->prov, keyexch->name_id, fn, data);
}
const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch)
{
void *provctx;
if (keyexch == NULL || keyexch->gettable_ctx_params == NULL)
return NULL;
provctx = ossl_provider_ctx(EVP_KEYEXCH_provider(keyexch));
return keyexch->gettable_ctx_params(provctx);
}
const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch)
{
void *provctx;
if (keyexch == NULL || keyexch->settable_ctx_params == NULL)
return NULL;
provctx = ossl_provider_ctx(EVP_KEYEXCH_provider(keyexch));
return keyexch->settable_ctx_params(provctx);
}
