/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   RDP licensing negotiation
   Copyright (C) Matthew Chapman 1999-2008

   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.

   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.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "frdp.h"
#include "crypto.h"
#include "secure.h"
#include "licence.h"
#include "rdp.h"
#include "rdpset.h"
#include "mem.h"
#include "debug.h"

/* Generate a session key and RC4 keys, given client and server randoms */
static void
licence_generate_keys(rdpLicence * licence, uint8 * client_random, uint8 * server_random,
		      uint8 * pre_master_secret)
{
	uint8 master_secret[48];
	uint8 key_block[48];

	/* Generate master secret and then key material */
	sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
	sec_hash_48(key_block, master_secret, server_random, client_random, 'A');

	/* Store first 16 bytes of session key as MAC secret */
	memcpy(licence->licence_sign_key, key_block, 16);

	/* Generate RC4 key from next 16 bytes */
	sec_hash_16(licence->licence_key, &key_block[16], client_random, server_random);
}

static void
licence_generate_hwid(rdpLicence * licence, uint8 * hwid)
{
	buf_out_uint32(hwid, 2);
	strncpy((char *) (hwid + 4), licence->sec->rdp->settings->hostname, LICENCE_HWID_SIZE - 4);
}

/* Send a Licensing packet with Client License Information */
static void
licence_present(rdpLicence * licence, uint8 * client_random, uint8 * rsa_data,
		uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
{
	uint32 sec_flags = SEC_LICENSE_PKT;
	uint16 length =
		16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
		licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
	STREAM s;

	s = sec_init(licence->sec, sec_flags, length + 4);

	/* Licensing Preamble (LICENSE_PREAMBLE) */
	out_uint8(s, LICENCE_TAG_PRESENT);	/* bMsgType LICENSE_INFO */
	out_uint8(s, 2);	/* bVersion PREAMBLE_VERSION_2_0 */
	out_uint16_le(s, length);

	/* Client License Information: */
	out_uint32_le(s, 1);	/* PreferredKeyExchangeAlg KEY_EXCHANGE_ALG_RSA */
	out_uint16_le(s, 0);	/* PlatformId, unknown platform and ISV */
	out_uint16_le(s, 0x0201);	/* PlatformId, build/version */

	out_uint8p(s, client_random, SEC_RANDOM_SIZE);	/* ClientRandom */

	/* Licensing Binary Blob with EncryptedPreMasterSecret: */
	out_uint16_le(s, 0);	/* wBlobType should be 0x0002 (BB_RANDOM_BLOB) */
	out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));	/* wBlobLen */
	out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);	/* 48 bit random number encrypted for server */
	out_uint8s(s, SEC_PADDING_SIZE);

	/* Licensing Binary Blob with LicenseInfo: */
	out_uint16_le(s, 1);	/* wBlobType BB_DATA_BLOB */
	out_uint16_le(s, licence_size);	/* wBlobLen */
	out_uint8p(s, licence_data, licence_size);	/* CAL issued by servers license server */

	/* Licensing Binary Blob with EncryptedHWID */
	out_uint16_le(s, 1);	/* wBlobType BB_DATA_BLOB */
	out_uint16_le(s, LICENCE_HWID_SIZE);	/* wBlobLen */
	out_uint8p(s, hwid, LICENCE_HWID_SIZE);	/* RC4-encrypted Client Hardware Identification */

	out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);	/* MACData */

	s_mark_end(s);
	sec_send(licence->sec, s, sec_flags);
}

/* Send a Licensing packet with Client New License Request */
static void
licence_send_request(rdpLicence * licence, uint8 * client_random, uint8 * rsa_data, char *user,
		     char *host)
{
	uint32 sec_flags = SEC_LICENSE_PKT;
	uint16 userlen = strlen(user) + 1;
	uint16 hostlen = strlen(host) + 1;
	uint16 length = 128 + userlen + hostlen;
	STREAM s;

	s = sec_init(licence->sec, sec_flags, length + 2);

	/* Licensing Preamble (LICENSE_PREAMBLE) */
	out_uint8(s, LICENCE_TAG_REQUEST);	/* NEW_LICENSE_REQUEST */
	out_uint8(s, 2);	/* PREAMBLE_VERSION_2_0 */
	out_uint16_le(s, length);

	out_uint32_le(s, 1);	/* PreferredKeyExchangeAlg KEY_EXCHANGE_ALG_RSA */
	out_uint16_le(s, 0);	/* PlatformId, unknown platform and ISV */
	out_uint16_le(s, 0xff01);	/* PlatformId, build/version */

	out_uint8p(s, client_random, SEC_RANDOM_SIZE);	/* ClientRandom */

	/* Licensing Binary Blob with EncryptedPreMasterSecret: */
	out_uint16_le(s, 0);	/* wBlobType should be 0x0002 (BB_RANDOM_BLOB) */
	out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));	/* wBlobLen */
	out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);	/* 48 bit random number encrypted for server */
	out_uint8s(s, SEC_PADDING_SIZE);

	/* Licensing Binary Blob with ClientUserName: */
	out_uint16_le(s, LICENCE_TAG_USER);	/* wBlobType BB_CLIENT_USER_NAME_BLOB */
	out_uint16_le(s, userlen);	/* wBlobLen */
	out_uint8p(s, user, userlen);

	/* Licensing Binary Blob with ClientMachineName: */
	out_uint16_le(s, LICENCE_TAG_HOST);	/* wBlobType BB_CLIENT_MACHINE_NAME_BLOB */
	out_uint16_le(s, hostlen);	/* wBlobLen */
	out_uint8p(s, host, hostlen);

	s_mark_end(s);
	sec_send(licence->sec, s, sec_flags);
}

/* Process a Server License Request packet */
static void
licence_process_demand(rdpLicence * licence, STREAM s)
{
	uint8 null_data[SEC_MODULUS_SIZE];
	uint8 *server_random;
	uint8 signature[LICENCE_SIGNATURE_SIZE];
	uint8 hwid[LICENCE_HWID_SIZE];
	uint8 *licence_data;
	int licence_size;
	CryptoRc4 crypt_key;

	/* Retrieve the server random from the incoming packet */
	in_uint8p(s, server_random, SEC_RANDOM_SIZE);	/* ServerRandom */
	/* Ignoring: ProductInfo, KeyExchangeList, ServerCertificate & ScopeList */

	/* We currently use null client keys. This is a bit naughty but, hey,
	   the security of licence negotiation isn't exactly paramount. */
	memset(null_data, 0, sizeof(null_data));
	licence_generate_keys(licence, null_data, server_random, null_data);

	licence_size = load_licence(&licence_data);
	if (licence_size > 0)
	{
		/* Generate a signature for the HWID buffer */
		licence_generate_hwid(licence, hwid);
		sec_sign(signature, 16, licence->licence_sign_key, 16, hwid, sizeof(hwid));

		/* Now encrypt the HWID */
		crypt_key = crypto_rc4_init(licence->licence_key, 16);
		crypto_rc4(crypt_key, sizeof(hwid), hwid, hwid);
		crypto_rc4_free(crypt_key);

		licence_present(licence, null_data, null_data, licence_data, licence_size, hwid, signature);
		xfree(licence_data);
		return;
	}

	licence_send_request(licence, null_data, null_data,
			     licence->sec->rdp->settings->username,
			     licence->sec->rdp->settings->hostname);
}

/* Send a Licensing packet with Platform Challenge Response */
static void
licence_send_authresp(rdpLicence * licence, uint8 * token, uint8 * crypt_hwid, uint8 * signature)
{
	uint32 sec_flags = SEC_LICENSE_PKT;
	uint16 length = 58;
	STREAM s;

	s = sec_init(licence->sec, sec_flags, length + 2);

	/* Licensing Preamble (LICENSE_PREAMBLE) */
	out_uint8(s, LICENCE_TAG_AUTHRESP);	/* PLATFORM_CHALLENGE_RESPONSE */
	out_uint8(s, 2);	/* PREAMBLE_VERSION_2_0 */
	out_uint16_le(s, length);

	/* Licensing Binary BLOB with EncryptedPlatformChallengeResponse: */
	out_uint16_le(s, 1);	/* wBlobType should be 0x0009 (BB_ENCRYPTED_DATA_BLOB) */
	out_uint16_le(s, LICENCE_TOKEN_SIZE);	/* wBlobLen */
	out_uint8p(s, token, LICENCE_TOKEN_SIZE);	/* RC4-encrypted challenge data */

	/* Licensing Binary BLOB with EncryptedHWID: */
	out_uint16_le(s, 1);	/* wBlobType should be 0x0009 (BB_ENCRYPTED_DATA_BLOB) */
	out_uint16_le(s, LICENCE_HWID_SIZE);	/* wBlobLen */
	out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);	/* RC4-encrypted Client Hardware Identification */

	out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);	/* MACData */

	s_mark_end(s);
	sec_send(licence->sec, s, sec_flags);
}

/* Parse a Server Platform Challenge packet */
static RD_BOOL
licence_parse_authreq(rdpLicence * licence, STREAM s, uint8 ** token, uint8 ** signature)
{
	uint16 tokenlen;

	in_uint8s(s, 4);	/* ConnectFlags (unused) */

	/* Licensing Binary BLOB with EncryptedPlatformChallenge: */
	in_uint8s(s, 2);	/* wBlobType (unused) */
	in_uint16_le(s, tokenlen);	/* wBlobLen */
	if (tokenlen != LICENCE_TOKEN_SIZE)
	{
		ui_error(licence->sec->rdp->inst, "token len %d\n", tokenlen);
		return False;
	}
	in_uint8p(s, *token, tokenlen);	/* RC4-encrypted challenge data */

	in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);	/* MACData for decrypted challenge data */

	return s_check_end(s);
}

/* Process a Server Platform Challenge packet */
static void
licence_process_authreq(rdpLicence * licence, STREAM s)
{
	uint8 *in_token = NULL, *in_sig;
	uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
	uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
	uint8 out_sig[LICENCE_SIGNATURE_SIZE];
	CryptoRc4 crypt_key;

	/* Parse incoming packet and save the encrypted token */
	licence_parse_authreq(licence, s, &in_token, &in_sig);
	memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);

	/* Decrypt the token. It should read TEST in Unicode. */
	crypt_key = crypto_rc4_init(licence->licence_key, 16);
	crypto_rc4(crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
	crypto_rc4_free(crypt_key);

	/* Generate a signature for a buffer of token and HWID */
	licence_generate_hwid(licence, hwid);
	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
	memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
	sec_sign(out_sig, 16, licence->licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));

	/* Now encrypt the HWID */
	crypt_key = crypto_rc4_init(licence->licence_key, 16);
	crypto_rc4(crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
	crypto_rc4_free(crypt_key);

	licence_send_authresp(licence, out_token, crypt_hwid, out_sig);
}

/* Process a Server New (or Upgrade) License packet */
static void
licence_process_issue(rdpLicence * licence, STREAM s)
{
	int i;
	uint32 length;
	uint32 os_major;
	uint32 os_minor;
	CryptoRc4 crypt_key;

	/* Licensing Binary BLOB with EncryptedLicenseInfo: */
	in_uint8s(s, 2);	/* wBlobType should be 0x0009 (BB_ENCRYPTED_DATA_BLOB) */
	in_uint16_le(s, length);	/* wBlobLen */

	/* RC4-encrypted New License Information */
	if (!s_check_rem(s, length))
		return;

	crypt_key = crypto_rc4_init(licence->licence_key, 16);
	crypto_rc4(crypt_key, length, s->p, s->p);	/* decrypt in place */
	crypto_rc4_free(crypt_key);

	/* dwVersion */
	in_uint16_le(s, os_major);	/* OS major version */
	in_uint16_le(s, os_minor);	/* OS minor version */

	/* Skip Scope, CompanyName and ProductId */
	for (i = 0; i < 3; i++)
	{
		in_uint32_le(s, length);
		if (!s_check_rem(s, length))
			return;
		in_uint8s(s, length);
	}

	/* LicenseInfo - CAL from license server */
	in_uint32_le(s, length);
	if (!s_check_rem(s, length))
		return;
	licence->licence_issued = True;
	save_licence(s->p, length);
}

/* Process a Licensing packet */
void
licence_process(rdpLicence * licence, STREAM s)
{
	uint8 tag;

	/* Licensing Preamble */
	in_uint8(s, tag);	/* bMsgType */
	in_uint8s(s, 1);	/* Ignoring bVersion */
	in_uint8s(s, 2);	/* Ignoring wMsgSize */
	/* Now pointing at LicensingMessage */

	switch (tag)
	{
		case LICENCE_TAG_DEMAND:	/* LICENSE_REQUEST */
			licence_process_demand(licence, s);
			break;

		case LICENCE_TAG_AUTHREQ:	/* PLATFORM_CHALLENGE */
			licence_process_authreq(licence, s);
			break;

		case LICENCE_TAG_ISSUE:	/* NEW_LICENSE */
			licence_process_issue(licence, s);
			break;

		case LICENCE_TAG_REISSUE:	/* UPGRADE_LICENSE */
			break;

		case LICENCE_TAG_RESULT:	/* ERROR_ALERT */
			DEBUG("LICENCE ERROR_ALERT - assuming it is a license grant\n");
			licence->licence_issued = True;	/* TODO ... */
			break;

		default:
			ui_unimpl(licence->sec->rdp->inst, "licence tag 0x%x\n", tag);
	}
}

rdpLicence *
licence_new(struct rdp_sec *sec)
{
	rdpLicence *self;

	self = (rdpLicence *) xmalloc(sizeof(rdpLicence));
	if (self != NULL)
	{
		memset(self, 0, sizeof(rdpLicence));
		self->sec = sec;
	}
	return self;
}

void
licence_free(rdpLicence * licence)
{
	if (licence != NULL)
	{
		xfree(licence);
	}
}