keymgmt_lib.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/core_names.h>
#include "internal/cryptlib.h"
#include "internal/nelem.h"
#include "crypto/evp.h"
#include "crypto/asn1.h"
#include "internal/core.h"
#include "internal/provider.h"
#include "evp_local.h"
/*
* match_type() checks if two EVP_KEYMGMT are matching key types. This
* function assumes that the caller has made all the necessary NULL checks.
*/
static int match_type(const EVP_KEYMGMT *keymgmt1, const EVP_KEYMGMT *keymgmt2)
{
const OSSL_PROVIDER *prov2 = EVP_KEYMGMT_provider(keymgmt2);
const char *name2 = evp_first_name(prov2, EVP_KEYMGMT_number(keymgmt2));
return EVP_KEYMGMT_is_a(keymgmt1, name2);
}
struct import_data_st {
EVP_KEYMGMT *keymgmt;
void *keydata;
int selection;
};
static int try_import(const OSSL_PARAM params[], void *arg)
{
struct import_data_st *data = arg;
/*
* It's fine if there was no data to transfer, we just end up with an
* empty destination key.
*/
if (params[0].key == NULL)
return 1;
/* Just in time creation of keydata, if needed */
if (data->keydata == NULL
&& (data->keydata = evp_keymgmt_newdata(data->keymgmt)) == NULL) {
ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
return 0;
}
return evp_keymgmt_import(data->keymgmt, data->keydata, data->selection,
params);
}
void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt)
{
struct import_data_st import_data;
size_t i = 0;
/* Export to where? */
if (keymgmt == NULL)
return NULL;
/* If we have an unassigned key, give up */
if (pk->keydata == NULL)
return NULL;
/* If |keymgmt| matches the "origin" |keymgmt|, no more to do */
if (pk->keymgmt == keymgmt)
return pk->keydata;
/* If this key is already exported to |keymgmt|, no more to do */
i = evp_keymgmt_util_find_operation_cache_index(pk, keymgmt);
if (i < OSSL_NELEM(pk->operation_cache)
&& pk->operation_cache[i].keymgmt != NULL)
return pk->operation_cache[i].keydata;
/* If the "origin" |keymgmt| doesn't support exporting, give up */
/*
* TODO(3.0) consider an evp_keymgmt_export() return value that indicates
* that the method is unsupported.
*/
if (pk->keymgmt->export == NULL)
return NULL;
/* Check that we have found an empty slot in the export cache */
/*
* TODO(3.0) Right now, we assume we have ample space. We will have to
* think about a cache aging scheme, though, if |i| indexes outside the
* array.
*/
if (!ossl_assert(i < OSSL_NELEM(pk->operation_cache)))
return NULL;
/*
* Make sure that the type of the keymgmt to export to matches the type
* of the "origin"
*/
if (!ossl_assert(match_type(pk->keymgmt, keymgmt)))
return NULL;
/*
* We look at the already cached provider keys, and import from the
* first that supports it (i.e. use its export function), and export
* the imported data to the new provider.
*/
/* Setup for the export callback */
import_data.keydata = NULL; /* try_import will create it */
import_data.keymgmt = keymgmt;
import_data.selection = OSSL_KEYMGMT_SELECT_ALL;
/*
* The export function calls the callback (try_import), which does the
* import for us. If successful, we're done.
*/
if (!evp_keymgmt_export(pk->keymgmt, pk->keydata, OSSL_KEYMGMT_SELECT_ALL,
&try_import, &import_data)) {
/* If there was an error, bail out */
evp_keymgmt_freedata(keymgmt, import_data.keydata);
return NULL;
}
/* Add the new export to the operation cache */
if (!evp_keymgmt_util_cache_keydata(pk, i, keymgmt, import_data.keydata)) {
evp_keymgmt_freedata(keymgmt, import_data.keydata);
return NULL;
}
return import_data.keydata;
}
void evp_keymgmt_util_clear_operation_cache(EVP_PKEY *pk)
{
size_t i, end = OSSL_NELEM(pk->operation_cache);
if (pk != NULL) {
for (i = 0; i < end && pk->operation_cache[i].keymgmt != NULL; i++) {
EVP_KEYMGMT *keymgmt = pk->operation_cache[i].keymgmt;
void *keydata = pk->operation_cache[i].keydata;
pk->operation_cache[i].keymgmt = NULL;
pk->operation_cache[i].keydata = NULL;
evp_keymgmt_freedata(keymgmt, keydata);
EVP_KEYMGMT_free(keymgmt);
}
}
}
size_t evp_keymgmt_util_find_operation_cache_index(EVP_PKEY *pk,
EVP_KEYMGMT *keymgmt)
{
size_t i, end = OSSL_NELEM(pk->operation_cache);
for (i = 0; i < end && pk->operation_cache[i].keymgmt != NULL; i++) {
if (keymgmt == pk->operation_cache[i].keymgmt)
break;
}
return i;
}
int evp_keymgmt_util_cache_keydata(EVP_PKEY *pk, size_t index,
EVP_KEYMGMT *keymgmt, void *keydata)
{
if (keydata != NULL) {
if (!EVP_KEYMGMT_up_ref(keymgmt))
return 0;
pk->operation_cache[index].keydata = keydata;
pk->operation_cache[index].keymgmt = keymgmt;
}
return 1;
}
void evp_keymgmt_util_cache_keyinfo(EVP_PKEY *pk)
{
/*
* Cache information about the provider "origin" key.
*
* This services functions like EVP_PKEY_size, EVP_PKEY_bits, etc
*/
if (pk->keydata != NULL) {
int bits = 0;
int security_bits = 0;
int size = 0;
OSSL_PARAM params[4];
params[0] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_BITS, &bits);
params[1] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_SECURITY_BITS,
&security_bits);
params[2] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_MAX_SIZE, &size);
params[3] = OSSL_PARAM_construct_end();
if (evp_keymgmt_get_params(pk->keymgmt, pk->keydata, params)) {
pk->cache.size = size;
pk->cache.bits = bits;
pk->cache.security_bits = security_bits;
}
}
}
void *evp_keymgmt_util_fromdata(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
int selection, const OSSL_PARAM params[])
{
void *keydata = NULL;
if ((keydata = evp_keymgmt_newdata(keymgmt)) == NULL
|| !evp_keymgmt_import(keymgmt, keydata, selection, params)
|| !EVP_PKEY_set_type_by_keymgmt(target, keymgmt)) {
evp_keymgmt_freedata(keymgmt, keydata);
keydata = NULL;
}
if (keydata != NULL) {
target->keydata = keydata;
evp_keymgmt_util_cache_keyinfo(target);
}
return keydata;
}
int evp_keymgmt_util_has(EVP_PKEY *pk, int selection)
{
/* Check if key is even assigned */
if (pk->keymgmt == NULL)
return 0;
return evp_keymgmt_has(pk->keymgmt, pk->keydata, selection);
}
/*
* evp_keymgmt_util_match() doesn't just look at the provider side "origin",
* but also in the operation cache to see if there's any common keymgmt that
* supplies OP_keymgmt_match.
*
* evp_keymgmt_util_match() adheres to the return values that EVP_PKEY_cmp()
* and EVP_PKEY_cmp_parameters() return, i.e.:
*
* 1 same key
* 0 not same key
* -1 not same key type
* -2 unsupported operation
*/
int evp_keymgmt_util_match(EVP_PKEY *pk1, EVP_PKEY *pk2, int selection)
{
EVP_KEYMGMT *keymgmt1 = NULL, *keymgmt2 = NULL;
void *keydata1 = NULL, *keydata2 = NULL;
if (pk1 == NULL || pk2 == NULL) {
if (pk1 == NULL && pk2 == NULL)
return 1;
return 0;
}
keymgmt1 = pk1->keymgmt;
keydata1 = pk1->keydata;
keymgmt2 = pk2->keymgmt;
keydata2 = pk2->keydata;
if (keymgmt1 != keymgmt2) {
/*
* The condition for a successful cross export is that the
* keydata to be exported is NULL (typed, but otherwise empty
* EVP_PKEY), or that it was possible to export it with
* evp_keymgmt_util_export_to_provider().
*
* We use |ok| to determine if it's ok to cross export one way,
* but also to determine if we should attempt a cross export
* the other way. There's no point doing it both ways.
*/
int ok = 1;
/* Complex case, where the keymgmt differ */
if (keymgmt1 != NULL
&& keymgmt2 != NULL
&& !match_type(keymgmt1, keymgmt2)) {
ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
return -1; /* Not the same type */
}
/*
* The key types are determined to match, so we try cross export,
* but only to keymgmt's that supply a matching function.
*/
if (keymgmt2 != NULL
&& keymgmt2->match != NULL) {
void *tmp_keydata = NULL;
ok = 1;
if (keydata1 != NULL) {
tmp_keydata =
evp_keymgmt_util_export_to_provider(pk1, keymgmt2);
ok = (tmp_keydata != NULL);
}
if (ok) {
keymgmt1 = keymgmt2;
keydata1 = tmp_keydata;
}
}
/*
* If we've successfully cross exported one way, there's no point
* doing it the other way, hence the |!ok| check.
*/
if (!ok
&& keymgmt1 != NULL
&& keymgmt1->match != NULL) {
void *tmp_keydata = NULL;
ok = 1;
if (keydata2 != NULL) {
tmp_keydata =
evp_keymgmt_util_export_to_provider(pk2, keymgmt1);
ok = (tmp_keydata != NULL);
}
if (ok) {
keymgmt2 = keymgmt1;
keydata2 = tmp_keydata;
}
}
}
/* If we still don't have matching keymgmt implementations, we give up */
if (keymgmt1 != keymgmt2)
return -2;
/* If both keydata are NULL, then they're the same key */
if (keydata1 == NULL && keydata2 == NULL)
return 1;
/* If only one of the keydata is NULL, then they're different keys */
if (keydata1 == NULL || keydata2 == NULL)
return 0;
/* If both keydata are non-NULL, we let the backend decide */
return evp_keymgmt_match(keymgmt1, keydata1, keydata2, selection);
}
int evp_keymgmt_util_copy(EVP_PKEY *to, EVP_PKEY *from, int selection)
{
/* Save copies of pointers we want to play with without affecting |to| */
EVP_KEYMGMT *to_keymgmt = to->keymgmt;
void *to_keydata = to->keydata, *alloc_keydata = NULL;
/* An unassigned key can't be copied */
if (from == NULL || from->keydata == NULL)
return 0;
if (to_keymgmt == from->keymgmt && to_keymgmt->copy != NULL) {
/* Make sure there's somewhere to copy to */
if (to_keydata == NULL
&& (to_keydata = evp_keymgmt_newdata(to_keymgmt)) == NULL) {
ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
return 0;
}
/*
* |to| and |from| have the same keymgmt, and the copy function is
* implemented, so just copy and be done
*/
if (!evp_keymgmt_copy(to_keymgmt, to_keydata, from->keydata,
selection))
return 0;
} else if (match_type(to_keymgmt, from->keymgmt)) {
struct import_data_st import_data;
import_data.keymgmt = to_keymgmt;
import_data.keydata = to_keydata;
import_data.selection = selection;
if (!evp_keymgmt_export(from->keymgmt, from->keydata, selection,
&try_import, &import_data)) {
evp_keymgmt_freedata(to_keymgmt, alloc_keydata);
return 0;
}
/*
* In this case to_keydata was previously unallocated, try_import()
* may have created it for us.
*/
to_keydata = import_data.keydata;
} else {
ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
return 0;
}
if (to->keymgmt == NULL
&& !EVP_PKEY_set_type_by_keymgmt(to, to_keymgmt)) {
evp_keymgmt_freedata(to_keymgmt, alloc_keydata);
return 0;
}
to->keydata = to_keydata;
evp_keymgmt_util_cache_keyinfo(to);
return 1;
}
void *evp_keymgmt_util_gen(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
void *genctx, OSSL_CALLBACK *cb, void *cbarg)
{
void *keydata = NULL;
if ((keydata = evp_keymgmt_gen(keymgmt, genctx, cb, cbarg)) == NULL
|| !EVP_PKEY_set_type_by_keymgmt(target, keymgmt)) {
evp_keymgmt_freedata(keymgmt, keydata);
keydata = NULL;
}
if (keydata != NULL) {
target->keydata = keydata;
evp_keymgmt_util_cache_keyinfo(target);
}
return keydata;
}
/*
* Returns the same numbers as EVP_PKEY_get_default_digest_name()
* When the string from the EVP_KEYMGMT implementation is "", we use
* SN_undef, since that corresponds to what EVP_PKEY_get_default_nid()
* returns for no digest.
*/
int evp_keymgmt_util_get_deflt_digest_name(EVP_KEYMGMT *keymgmt,
void *keydata,
char *mdname, size_t mdname_sz)
{
OSSL_PARAM params[3];
char mddefault[100] = "";
char mdmandatory[100] = "";
char *result = NULL;
int rv = -2;
params[0] =
OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_DEFAULT_DIGEST,
mddefault, sizeof(mddefault));
params[0].return_size = sizeof(mddefault) + 1;
params[1] =
OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_MANDATORY_DIGEST,
mdmandatory,
sizeof(mdmandatory));
params[1].return_size = sizeof(mdmandatory) + 1;
params[2] = OSSL_PARAM_construct_end();
if (!evp_keymgmt_get_params(keymgmt, keydata, params))
return 0;
if (params[1].return_size != sizeof(mdmandatory) + 1) {
if (params[1].return_size == 1) /* Only a NUL byte */
result = SN_undef;
else
result = mdmandatory;
rv = 2;
} else if (params[0].return_size != sizeof(mddefault) + 1) {
if (params[0].return_size == 1) /* Only a NUL byte */
result = SN_undef;
else
result = mddefault;
rv = 1;
}
if (rv > 0)
OPENSSL_strlcpy(mdname, result, mdname_sz);
return rv;
}
