217 lines
5.0 KiB
C
217 lines
5.0 KiB
C
/*
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* Copyright (C) 2013 Tobias Brunner
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* HSR Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include "pkcs7_encrypted_data.h"
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#include <asn1/asn1.h>
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#include <asn1/asn1_parser.h>
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#include <asn1/oid.h>
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#include <crypto/pkcs5.h>
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#include <utils/debug.h>
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typedef struct private_pkcs7_encrypted_data_t private_pkcs7_encrypted_data_t;
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/**
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* Private data of a PKCS#7 signed-data container.
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*/
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struct private_pkcs7_encrypted_data_t {
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/**
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* Implements pkcs7_t.
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*/
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pkcs7_t public;
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/**
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* Decrypted content
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*/
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chunk_t content;
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/**
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* Encrypted and encoded PKCS#7 encrypted-data
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*/
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chunk_t encoding;
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};
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/**
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* Decrypt encrypted-data with available passwords
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*/
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static bool decrypt(pkcs5_t *pkcs5, chunk_t data, chunk_t *decrypted)
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{
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enumerator_t *enumerator;
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shared_key_t *shared;
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bool success = FALSE;
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enumerator = lib->credmgr->create_shared_enumerator(lib->credmgr,
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SHARED_PRIVATE_KEY_PASS, NULL, NULL);
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while (enumerator->enumerate(enumerator, &shared, NULL, NULL))
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{
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if (pkcs5->decrypt(pkcs5, shared->get_key(shared), data, decrypted))
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{
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success = TRUE;
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break;
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}
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}
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enumerator->destroy(enumerator);
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return success;
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}
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/**
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* ASN.1 definition of the PKCS#7 encrypted-data type
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*/
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static const asn1Object_t encryptedDataObjects[] = {
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{ 0, "encryptedData", ASN1_SEQUENCE, ASN1_NONE }, /* 0 */
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{ 1, "version", ASN1_INTEGER, ASN1_BODY }, /* 1 */
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{ 1, "encryptedContentInfo", ASN1_SEQUENCE, ASN1_OBJ }, /* 2 */
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{ 2, "contentType", ASN1_OID, ASN1_BODY }, /* 3 */
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{ 2, "contentEncryptionAlgorithm", ASN1_EOC, ASN1_RAW }, /* 4 */
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{ 2, "encryptedContent", ASN1_CONTEXT_S_0, ASN1_BODY }, /* 5 */
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{ 0, "exit", ASN1_EOC, ASN1_EXIT }
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};
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#define PKCS7_VERSION 1
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#define PKCS7_CONTENT_TYPE 3
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#define PKCS7_CONTENT_ENC_ALGORITHM 4
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#define PKCS7_ENCRYPTED_CONTENT 5
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/**
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* Parse and decrypt encrypted-data
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*/
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static bool parse(private_pkcs7_encrypted_data_t *this, chunk_t content)
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{
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asn1_parser_t *parser;
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chunk_t object;
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int objectID, version;
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bool success = FALSE;
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chunk_t encrypted = chunk_empty;
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pkcs5_t *pkcs5 = NULL;
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parser = asn1_parser_create(encryptedDataObjects, content);
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while (parser->iterate(parser, &objectID, &object))
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{
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int level = parser->get_level(parser);
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switch (objectID)
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{
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case PKCS7_VERSION:
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version = object.len ? (int)*object.ptr : 0;
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DBG2(DBG_LIB, " v%d", version);
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if (version != 0)
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{
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DBG1(DBG_LIB, "encryptedData version is not 0");
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goto end;
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}
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break;
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case PKCS7_CONTENT_TYPE:
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if (asn1_known_oid(object) != OID_PKCS7_DATA)
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{
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DBG1(DBG_LIB, "encrypted content not of type pkcs7 data");
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goto end;
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}
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break;
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case PKCS7_CONTENT_ENC_ALGORITHM:
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pkcs5 = pkcs5_from_algorithmIdentifier(object, level + 1);
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if (!pkcs5)
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{
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DBG1(DBG_LIB, "failed to detect PKCS#5 scheme");
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goto end;
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}
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break;
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case PKCS7_ENCRYPTED_CONTENT:
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encrypted = object;
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break;
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}
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}
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success = parser->success(parser);
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end:
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parser->destroy(parser);
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success = success && decrypt(pkcs5, encrypted, &this->content);
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DESTROY_IF(pkcs5);
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return success;
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}
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METHOD(container_t, get_type, container_type_t,
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private_pkcs7_encrypted_data_t *this)
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{
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return CONTAINER_PKCS7_ENCRYPTED_DATA;
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}
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METHOD(container_t, get_data, bool,
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private_pkcs7_encrypted_data_t *this, chunk_t *data)
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{
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if (this->content.len)
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{
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*data = chunk_clone(this->content);
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return TRUE;
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}
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return FALSE;
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}
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METHOD(container_t, get_encoding, bool,
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private_pkcs7_encrypted_data_t *this, chunk_t *data)
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{
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*data = chunk_clone(this->encoding);
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return TRUE;
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}
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METHOD(container_t, destroy, void,
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private_pkcs7_encrypted_data_t *this)
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{
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free(this->content.ptr);
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free(this->encoding.ptr);
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free(this);
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}
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/**
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* Generic constructor
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*/
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static private_pkcs7_encrypted_data_t* create_empty()
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{
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private_pkcs7_encrypted_data_t *this;
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INIT(this,
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.public = {
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.container = {
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.get_type = _get_type,
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.create_signature_enumerator = (void*)enumerator_create_empty,
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.get_data = _get_data,
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.get_encoding = _get_encoding,
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.destroy = _destroy,
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},
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.create_cert_enumerator = (void*)enumerator_create_empty,
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.get_attribute = (void*)return_false,
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},
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);
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return this;
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}
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/**
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* See header.
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*/
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pkcs7_t *pkcs7_encrypted_data_load(chunk_t encoding, chunk_t content)
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{
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private_pkcs7_encrypted_data_t *this = create_empty();
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this->encoding = chunk_clone(encoding);
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if (!parse(this, content))
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{
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destroy(this);
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return NULL;
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}
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return &this->public;
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}
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