/* Certificate support for IKE authentication
 * 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.
 *
 * RCSID $Id$
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include <freeswan.h>
#include <ipsec_policy.h>

#include "constants.h"
#include "defs.h"
#include "log.h"
#include "asn1.h"
#include "id.h"
#include "x509.h"
#include "pgp.h"
#include "pem.h"
#include "certs.h"
#include "pkcs1.h"

/*
 * used for initializatin of certs
 */
const cert_t empty_cert = {CERT_NONE, {NULL}};

/*
 * extracts the certificate to be sent to the peer
 */
chunk_t
get_mycert(cert_t cert)
{
    switch (cert.type)
    {
    case CERT_PGP:
	return cert.u.pgp->certificate;
    case CERT_X509_SIGNATURE:
	return cert.u.x509->certificate;
    default:
	return empty_chunk;
    }
}

/* load a coded key or certificate file with autodetection
 * of binary DER or base64 PEM ASN.1 formats and armored PGP format
 */
bool
load_coded_file(const char *filename, prompt_pass_t *pass, const char *type
, chunk_t *blob, bool *pgp)
{
    err_t ugh = NULL;

    FILE *fd = fopen(filename, "r");

    if (fd)
    {
	int bytes;
	fseek(fd, 0, SEEK_END );
	blob->len = ftell(fd);
	rewind(fd);
	blob->ptr = alloc_bytes(blob->len, type);
	bytes = fread(blob->ptr, 1, blob->len, fd);
	fclose(fd);
	plog("  loaded %s file '%s' (%d bytes)", type, filename, bytes);

	*pgp = FALSE;

	/* try DER format */
	if (is_asn1(*blob))
	{
	    DBG(DBG_PARSING,
		DBG_log("  file coded in DER format");
	    )
	    return TRUE;
	}

	/* try PEM format */
	ugh = pemtobin(blob, pass, filename, pgp);

	if (ugh == NULL)
	{
	    if (*pgp)
	    {
                DBG(DBG_PARSING,
                    DBG_log("  file coded in armored PGP format");
                )
                return TRUE;
	    }
	    if (is_asn1(*blob))
	    {
		DBG(DBG_PARSING,
		    DBG_log("  file coded in PEM format");
		)
		return TRUE;
	    }
	    ugh = "file coded in unknown format, discarded";
	}

	/* a conversion error has occured */
	plog("  %s", ugh);
	pfree(blob->ptr);
	*blob = empty_chunk;
    }
    else
    {
	plog("  could not open %s file '%s'", type, filename);
    }
    return FALSE;
}

/*
 *  Loads a PKCS#1 or PGP private RSA key file
 */
err_t
load_rsa_private_key(const char* filename, prompt_pass_t *pass
, RSA_private_key_t *key)
{
    err_t ugh = NULL;
    bool pgp = FALSE;
    chunk_t blob = empty_chunk;

    const char *path = concatenate_paths(PRIVATE_KEY_PATH, filename);

    if (load_coded_file(path, pass, "private key", &blob, &pgp))
    {
	if (pgp)
	{
	    if (!parse_pgp(blob, NULL, key))
		ugh = "syntax error in PGP private key file";
	}
	else
	{
	    if (!pkcs1_parse_private_key(blob, key))
		ugh = "syntax error in PKCS#1 private key file";
	}
	pfree(blob.ptr);
    }
    else
	ugh = "error loading RSA private key file";

    return ugh;
}
/*
 *  Loads a X.509 or OpenPGP certificate
 */
bool
load_cert(const char *filename, const char *label, cert_t *cert)
{
    bool pgp = FALSE;
    chunk_t blob = empty_chunk;

    /* initialize cert struct */
    cert->type = CERT_NONE;
    cert->u.x509 = NULL;

    if (load_coded_file(filename, NULL, label, &blob, &pgp))
    {
	if (pgp)
	{
	    pgpcert_t *pgpcert = alloc_thing(pgpcert_t, "pgpcert");
	    *pgpcert = empty_pgpcert;
	    if (parse_pgp(blob, pgpcert, NULL))
	    {
		cert->type = CERT_PGP;
		cert->u.pgp = pgpcert;
		return TRUE;
	    }
	    else
	    {
		plog("  error in OpenPGP certificate");
		free_pgpcert(pgpcert);
		return FALSE;
	    }
	}
	else
	{
	    x509cert_t *x509cert = alloc_thing(x509cert_t, "x509cert");
	    *x509cert = empty_x509cert;
	    if (parse_x509cert(blob, 0, x509cert))
	    {
		cert->type = CERT_X509_SIGNATURE;
		cert->u.x509 = x509cert;
		return TRUE;
	    }
	    else
	    {
		plog("  error in X.509 certificate");
		free_x509cert(x509cert);
		return FALSE;
	    }
	}
    }
    return FALSE;
}

/*
 *  Loads a host certificate
 */
bool
load_host_cert(const char *filename, cert_t *cert)
{
    const char *path = concatenate_paths(HOST_CERT_PATH, filename);

    return load_cert(path, "host cert", cert);
}

/*
 *  Loads a CA certificate
 */
bool
load_ca_cert(const char *filename, cert_t *cert)
{
    const char *path = concatenate_paths(CA_CERT_PATH, filename);

    return load_cert(path, "CA cert", cert);
}

/*
 * establish equality of two certificates
 */
bool
same_cert(const cert_t *a, const cert_t *b)
{
    return a->type == b->type && a->u.x509 == b->u.x509;
}

/*  for each link pointing to the certif icate
 "  increase the count by one
 */
void
share_cert(cert_t cert)
{
    switch (cert.type)
    {
    case CERT_PGP:
	share_pgpcert(cert.u.pgp);
	break;
    case CERT_X509_SIGNATURE:
	share_x509cert(cert.u.x509);
	break;
    default:
        break;
    }
}

/*  release of a certificate decreases the count by one
 "  the certificate is freed when the counter reaches zero
 */
void
release_cert(cert_t cert)
{
   switch (cert.type)
    {
    case CERT_PGP:
	release_pgpcert(cert.u.pgp);
	break;
    case CERT_X509_SIGNATURE:
	release_x509cert(cert.u.x509);
	break;
    default:
        break;
    }
}

/*
 *  list all X.509 and OpenPGP end certificates
 */
void
list_certs(bool utc)
{
    list_x509_end_certs(utc);
    list_pgp_end_certs(utc);
}