/*
 * Support of PKCS#1 and PKCS#7 data structures
 *
 * Copyright (C) 2002-2004 Andreas Steffen, Zuercher Hochschule Winterthur
 *
 * 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 <stdlib.h>
#include <string.h>

#include <libreswan.h>

#include "constants.h"
#include "lswlog.h"

#include "lswalloc.h"
#include "lswconf.h"
#include "asn1.h"
#include "oid.h"
#include "id.h"
#include "x509.h"
#include "certs.h"
#include "pkcs.h"

/* ASN.1 definition of a PKCS#1 RSA private key */
static const asn1Object_t privkeyObjects[] = {
	{ 0, "RSAPrivateKey", ASN1_SEQUENCE, ASN1_OBJ },	/* 0 */
	{ 1, "version", ASN1_INTEGER, ASN1_BODY },	/* 1 */
	{ 1, "modulus", ASN1_INTEGER, ASN1_BODY },	/* 2 */
	{ 1, "publicExponent", ASN1_INTEGER, ASN1_BODY },	/* 3 */
	{ 1, "privateExponent", ASN1_INTEGER, ASN1_BODY },	/* 4 */
	{ 1, "prime1", ASN1_INTEGER, ASN1_BODY },	/* 5 */
	{ 1, "prime2", ASN1_INTEGER, ASN1_BODY },	/* 6 */
	{ 1, "exponent1", ASN1_INTEGER, ASN1_BODY },	/* 7 */
	{ 1, "exponent2", ASN1_INTEGER, ASN1_BODY },	/* 8 */
	{ 1, "coefficient", ASN1_INTEGER, ASN1_BODY },	/* 9 */
	{ 1, "otherPrimeInfos", ASN1_SEQUENCE, ASN1_OPT | ASN1_LOOP },	/* 10 */
	{ 2, "otherPrimeInfo", ASN1_SEQUENCE, ASN1_NONE },	/* 11 */
	{ 3, "prime", ASN1_INTEGER, ASN1_BODY },	/* 12 */
	{ 3, "exponent", ASN1_INTEGER, ASN1_BODY },	/* 13 */
	{ 3, "coefficient", ASN1_INTEGER, ASN1_BODY },	/* 14 */
	{ 1, "end opt or loop", ASN1_EOC, ASN1_END }	/* 15 */
};

#define PKCS1_PRIV_KEY_OBJECT 0
#define PKCS1_PRIV_KEY_VERSION 1
#define PKCS1_PRIV_KEY_MODULUS 2
#define PKCS1_PRIV_KEY_COEFF 9
#define PKCS1_PRIV_KEY_ROOF 16

/* ASN.1 definition of the PKCS#7 ContentInfo type */

static const asn1Object_t contentInfoObjects[] = {
	{ 0, "contentInfo", ASN1_SEQUENCE, ASN1_NONE },	/* 0 */
	{ 1, "contentType", ASN1_OID, ASN1_BODY },	/* 1 */
	{ 1, "content", ASN1_CONTEXT_C_0, ASN1_OPT | ASN1_BODY },	/* 2 */
	{ 1, "end opt", ASN1_EOC, ASN1_END }	/* 3 */
};

#define PKCS7_INFO_TYPE 1
#define PKCS7_INFO_CONTENT 2
#define PKCS7_INFO_ROOF 4

/* ASN.1 definition of the PKCS#7 SignedData type */

static const asn1Object_t signedDataObjects[] = {
	{ 0, "signedData", ASN1_SEQUENCE, ASN1_NONE },	/* 0 */
	{ 1, "version", ASN1_INTEGER, ASN1_BODY },	/* 1 */
	{ 1, "digestAlgorithms", ASN1_SET, ASN1_BODY },	/* 2 */
	{ 1, "contentInfo", ASN1_SEQUENCE, ASN1_OBJ },	/* 3 */
	{ 1, "certificates", ASN1_CONTEXT_C_0, ASN1_OPT | ASN1_LOOP },	/* 4 */
	{ 2, "certificate", ASN1_SEQUENCE, ASN1_OBJ },	/* 5 */
	{ 1, "end opt or loop", ASN1_EOC, ASN1_END },	/* 6 */
	{ 1, "crls", ASN1_CONTEXT_C_1, ASN1_OPT | ASN1_LOOP },	/* 7 */
	{ 2, "crl", ASN1_SEQUENCE, ASN1_OBJ },	/* 8 */
	{ 1, "end opt or loop", ASN1_EOC, ASN1_END },	/* 9 */
	{ 1, "signerInfos", ASN1_SET, ASN1_BODY }	/* 10 */
};

#define PKCS7_SIGNED_CERT 5
#define PKCS7_SIGNED_ROOF 11


/*
 * Parse PKCS#7 wrapped X.509 certificates
 *
 * Allocates space for each cert found and links it onto *cert.
 * Returns FALSE for failure (but certs might have been added).
 */
static bool parse_pkcs7_signedData(chunk_t blob, int level0, x509cert_t **cert)
{
	asn1_ctx_t ctx;
	u_int objectID;

	asn1_init(&ctx, blob, level0, FALSE, DBG_RAW);

	for (objectID = 0; objectID < PKCS7_SIGNED_ROOF; objectID++) {
		chunk_t object;
		u_int level;

		if (!extract_object(signedDataObjects, &objectID, &object,
					&level, &ctx))
			return FALSE;

		if (objectID == PKCS7_SIGNED_CERT) {
			chunk_t cert_blob;
			x509cert_t *newcert =
				alloc_thing(x509cert_t,
					"pkcs7 wrapped x509cert");

			clonetochunk(cert_blob, object.ptr, object.len,
				"pkcs7 cert blob");
			*newcert = empty_x509cert;

			if (parse_x509cert(cert_blob, level + 1, newcert)) {
				newcert->next = *cert;
				*cert = newcert;
			} else {
				free_x509cert(newcert);
			}
		}
	}
	return TRUE;
}

/*
 * Parse PKCS#7 wrapped X.509 certificates
 */
bool parse_pkcs7_cert(chunk_t blob, x509cert_t **cert)
{
	asn1_ctx_t ctx;
	u_int objectID;

	asn1_init(&ctx, blob, 0, FALSE, DBG_RAW);

	for (objectID = 0; objectID < PKCS7_INFO_ROOF; objectID++) {
		chunk_t object;
		u_int level;

		if (!extract_object(contentInfoObjects, &objectID, &object,
					&level, &ctx))
			return FALSE;

		if (objectID == PKCS7_INFO_TYPE) {
			if (known_oid(object) != OID_PKCS7_SIGNED_DATA) {
				libreswan_log("PKCS#7 content type is not signedData");
				return FALSE;
			}
		} else if (objectID == PKCS7_INFO_CONTENT) {
			if (!parse_pkcs7_signedData(object, level + 1, cert))
				return FALSE;
		}
	}
	return TRUE;
}