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/*
* Copyright (C) 2012 Tobias Brunner
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include "pkcs8_builder.h"
#include <utils/debug.h>
#include <asn1/oid.h>
#include <asn1/asn1.h>
#include <asn1/asn1_parser.h>
#include <crypto/pkcs5.h>
#include <credentials/keys/private_key.h>
/**
* ASN.1 definition of a privateKeyInfo structure
*/
static const asn1Object_t pkinfoObjects[] = {
{ 0, "privateKeyInfo", ASN1_SEQUENCE, ASN1_NONE }, /* 0 */
{ 1, "version", ASN1_INTEGER, ASN1_BODY }, /* 1 */
{ 1, "privateKeyAlgorithm", ASN1_EOC, ASN1_RAW }, /* 2 */
{ 1, "privateKey", ASN1_OCTET_STRING, ASN1_BODY }, /* 3 */
{ 1, "attributes", ASN1_CONTEXT_C_0, ASN1_OPT }, /* 4 */
{ 1, "end opt", ASN1_EOC, ASN1_END }, /* 5 */
{ 0, "exit", ASN1_EOC, ASN1_EXIT }
};
#define PKINFO_PRIVATE_KEY_ALGORITHM 2
#define PKINFO_PRIVATE_KEY 3
/**
* Load a generic private key from an ASN.1 encoded blob
*/
static private_key_t *parse_private_key(chunk_t blob)
{
asn1_parser_t *parser;
chunk_t object, params = chunk_empty;
int objectID;
private_key_t *key = NULL;
key_type_t type = KEY_ANY;
builder_part_t part = BUILD_BLOB_ASN1_DER;
parser = asn1_parser_create(pkinfoObjects, blob);
parser->set_flags(parser, FALSE, TRUE);
while (parser->iterate(parser, &objectID, &object))
{
switch (objectID)
{
case PKINFO_PRIVATE_KEY_ALGORITHM:
{
int oid = asn1_parse_algorithmIdentifier(object,
parser->get_level(parser) + 1, ¶ms);
switch (oid)
{
case OID_RSASSA_PSS:
/* TODO: parameters associated with such keys should be
* treated as restrictions later when signing (the type
* itself is already a restriction). However, the
* builders currently don't expect any parameters for
* RSA keys (we also only pass along the params, not the
* exact type, so we'd have to guess that params
* indicate RSA/PSS, but they are optional so that won't
* work for keys without specific restrictions) */
params = chunk_empty;
/* fall-through */
case OID_RSA_ENCRYPTION:
type = KEY_RSA;
break;
case OID_EC_PUBLICKEY:
type = KEY_ECDSA;
break;
case OID_ED25519:
type = KEY_ED25519;
part = BUILD_EDDSA_PRIV_ASN1_DER;
break;
case OID_ED448:
type = KEY_ED448;
part = BUILD_EDDSA_PRIV_ASN1_DER;
break;
default:
/* key type not supported */
goto end;
}
break;
}
case PKINFO_PRIVATE_KEY:
{
DBG2(DBG_ASN, "-- > --");
if (params.ptr)
{
key = lib->creds->create(lib->creds, CRED_PRIVATE_KEY,
type, BUILD_BLOB_ALGID_PARAMS,
params, part, object, BUILD_END);
}
else
{
key = lib->creds->create(lib->creds, CRED_PRIVATE_KEY,
type, part, object, BUILD_END);
}
DBG2(DBG_ASN, "-- < --");
break;
}
}
}
end:
parser->destroy(parser);
return key;
}
/**
* Try to decrypt the given blob with multiple passwords using the given
* pkcs5 object.
*/
static private_key_t *decrypt_private_key(pkcs5_t *pkcs5, chunk_t blob)
{
enumerator_t *enumerator;
shared_key_t *shared;
private_key_t *private_key = NULL;
enumerator = lib->credmgr->create_shared_enumerator(lib->credmgr,
SHARED_PRIVATE_KEY_PASS, NULL, NULL);
while (enumerator->enumerate(enumerator, &shared, NULL, NULL))
{
chunk_t decrypted;
if (!pkcs5->decrypt(pkcs5, shared->get_key(shared), blob, &decrypted))
{
continue;
}
private_key = parse_private_key(decrypted);
if (private_key)
{
chunk_clear(&decrypted);
break;
}
chunk_free(&decrypted);
}
enumerator->destroy(enumerator);
return private_key;
}
/**
* ASN.1 definition of an encryptedPrivateKeyInfo structure
*/
static const asn1Object_t encryptedPKIObjects[] = {
{ 0, "encryptedPrivateKeyInfo", ASN1_SEQUENCE, ASN1_NONE }, /* 0 */
{ 1, "encryptionAlgorithm", ASN1_EOC, ASN1_RAW }, /* 1 */
{ 1, "encryptedData", ASN1_OCTET_STRING, ASN1_BODY }, /* 2 */
{ 0, "exit", ASN1_EOC, ASN1_EXIT }
};
#define EPKINFO_ENCRYPTION_ALGORITHM 1
#define EPKINFO_ENCRYPTED_DATA 2
/**
* Load an encrypted private key from an ASN.1 encoded blob
* Schemes per PKCS#5 (RFC 2898)
*/
static private_key_t *parse_encrypted_private_key(chunk_t blob)
{
asn1_parser_t *parser;
chunk_t object;
int objectID;
private_key_t *key = NULL;
pkcs5_t *pkcs5 = NULL;
parser = asn1_parser_create(encryptedPKIObjects, blob);
while (parser->iterate(parser, &objectID, &object))
{
switch (objectID)
{
case EPKINFO_ENCRYPTION_ALGORITHM:
{
pkcs5 = pkcs5_from_algorithmIdentifier(object,
parser->get_level(parser) + 1);
if (!pkcs5)
{
goto end;
}
break;
}
case EPKINFO_ENCRYPTED_DATA:
{
key = decrypt_private_key(pkcs5, object);
break;
}
}
}
end:
DESTROY_IF(pkcs5);
parser->destroy(parser);
return key;
}
/**
* See header.
*/
private_key_t *pkcs8_private_key_load(key_type_t type, va_list args)
{
chunk_t blob = chunk_empty;
private_key_t *key;
while (TRUE)
{
switch (va_arg(args, builder_part_t))
{
case BUILD_BLOB_ASN1_DER:
blob = va_arg(args, chunk_t);
continue;
case BUILD_END:
break;
default:
return NULL;
}
break;
}
/* we don't know whether it is encrypted or not, try both ways */
key = parse_encrypted_private_key(blob);
if (!key)
{
key = parse_private_key(blob);
}
return key;
}
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