src/lockdown.c

/*
 * lockdown.c
 * libiphone built-in lockdownd client
 * 
 * Copyright (c) 2008 Zach C. All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA 
 */

#include "usbmux.h"
#include "iphone.h"
#include "lockdown.h"
#include "userpref.h"
#include <arpa/inet.h>
#include <errno.h>
#include <string.h>
#include <glib.h>
#include <libtasn1.h>
#include <gnutls/x509.h>

const ASN1_ARRAY_TYPE pkcs1_asn1_tab[] = {
	{"PKCS1", 536872976, 0},
	{0, 1073741836, 0},
	{"RSAPublicKey", 536870917, 0},
	{"modulus", 1073741827, 0},
	{"publicExponent", 3, 0},
	{0, 0, 0}
};

int get_rand(int min, int max)
{
	int retval = (rand() % (max - min)) + min;
	return retval;
}

/** Generates a valid HostID (which is actually a UUID).
 *
 * @param A null terminated string containing a valid HostID.
 */
char *lockdownd_generate_hostid()
{
	char *hostid = (char *) malloc(sizeof(char) * 37);	// HostID's are just UUID's, and UUID's are 36 characters long
	const char *chars = "ABCDEF0123456789";
	srand(time(NULL));
	int i = 0;

	for (i = 0; i < 36; i++) {
		if (i == 8 || i == 13 || i == 18 || i == 23) {
			hostid[i] = '-';
			continue;
		} else {
			hostid[i] = chars[get_rand(0, 16)];
		}
	}
	hostid[36] = '\0';			// make it a real string
	return hostid;
}

/** Creates a lockdownd client for the give iPhone.
 *
 * @param phone The iPhone to create a lockdownd client for
 *
 * @return The lockdownd client.
 */
iphone_lckd_client_t new_lockdownd_client(iphone_device_t phone)
{
	if (!phone)
		return NULL;
	iphone_lckd_client_t control = (iphone_lckd_client_t) malloc(sizeof(struct iphone_lckd_client_int));

	if (IPHONE_E_SUCCESS != iphone_mux_new_client(phone, 0x0a00, 0xf27e, &control->connection)) {
		free(control);
		return NULL;
	}

	control->ssl_session = (gnutls_session_t *) malloc(sizeof(gnutls_session_t));
	control->in_SSL = 0;
	control->gtls_buffer_hack_len = 0;
	return control;
}


/** Closes the lockdownd client and does the necessary housekeeping.
 *
 * @param control The lockdown client
 */
iphone_error_t iphone_lckd_free_client(iphone_lckd_client_t client)
{
	if (!client)
		return IPHONE_E_INVALID_ARG;
	iphone_error_t ret = IPHONE_E_UNKNOWN_ERROR;

	if (client->connection) {
		ret = iphone_mux_free_client(client->connection);
	}

	if (client->ssl_session)
		gnutls_deinit(*client->ssl_session);
	free(client->ssl_session);
	free(client);
	return ret;
}

/** Polls the iPhone for lockdownd data.
 *
 * @param control The lockdownd client
 * @param dump_data The pointer to the location of the buffer in which to store
 *                  the received data
 *
 * @return The number of bytes received
 */
iphone_error_t iphone_lckd_recv(iphone_lckd_client_t client, char **dump_data, uint32_t * recv_bytes)
{
	if (!client || !dump_data || !recv_bytes)
		return IPHONE_E_INVALID_ARG;
	iphone_error_t ret = IPHONE_E_UNKNOWN_ERROR;
	char *receive;
	uint32 datalen = 0, bytes = 0;

	if (!client->in_SSL)
		ret = iphone_mux_recv(client->connection, (char *) &datalen, sizeof(datalen), &bytes);
	else {
		bytes = gnutls_record_recv(*client->ssl_session, &datalen, sizeof(datalen));
		if (bytes > 0)
			ret = IPHONE_E_SUCCESS;
	}
	datalen = ntohl(datalen);

	receive = (char *) malloc(sizeof(char) * datalen);
	if (!client->in_SSL)
		ret = iphone_mux_recv(client->connection, receive, datalen, &bytes);
	else {
		bytes = gnutls_record_recv(*client->ssl_session, receive, datalen);
		if (bytes > 0)
			ret = IPHONE_E_SUCCESS;
	}
	*dump_data = receive;
	*recv_bytes = bytes;
	return ret;
}

/** Sends lockdownd data to the iPhone
 * 
 * @note This function is low-level and should only be used if you need to send
 *        a new type of message.
 *
 * @param control The lockdownd client
 * @param raw_data The null terminated string buffer to send
 * @param length The length of data to send
 *
 * @return The number of bytes sent
 */
iphone_error_t iphone_lckd_send(iphone_lckd_client_t client, char *raw_data, uint32_t length, uint32_t * sent_bytes)
{
	if (!client || !raw_data || length == 0 || !sent_bytes)
		return IPHONE_E_INVALID_ARG;
	char *real_query;
	int bytes;
	iphone_error_t ret = IPHONE_E_UNKNOWN_ERROR;

	real_query = (char *) malloc(sizeof(char) * (length + 4));
	length = htonl(length);
	memcpy(real_query, &length, sizeof(length));
	memcpy(real_query + 4, raw_data, ntohl(length));
	log_debug_msg("lockdownd_send(): made the query, sending it along\n");
	dump_debug_buffer("grpkt", real_query, ntohl(length) + 4);

	if (!client->in_SSL)
		ret = iphone_mux_send(client->connection, real_query, ntohl(length) + sizeof(length), &bytes);
	else {
		gnutls_record_send(*client->ssl_session, real_query, ntohl(length) + sizeof(length));
		ret = IPHONE_E_SUCCESS;
	}
	log_debug_msg("lockdownd_send(): sent it!\n");
	free(real_query);
	*sent_bytes = bytes;
	return ret;
}

/** Initiates the handshake for the lockdown session. Part of the lockdownd handshake.
 * 
 * @note You most likely want lockdownd_init unless you are doing something special.
 *
 * @param control The lockdownd client
 *
 * @return 1 on success and 0 on failure.
 */
iphone_error_t lockdownd_hello(iphone_lckd_client_t control)
{
	if (!control)
		return IPHONE_E_INVALID_ARG;
	xmlDocPtr plist = new_plist();
	xmlNode *dict, *key;
	char **dictionary;
	int bytes = 0, i = 0;
	iphone_error_t ret = IPHONE_E_UNKNOWN_ERROR;

	log_debug_msg("lockdownd_hello() called\n");
	dict = add_child_to_plist(plist, "dict", "\n", NULL, 0);
	key = add_key_str_dict_element(plist, dict, "Request", "QueryType", 1);
	char *XML_content;
	uint32 length;

	xmlDocDumpMemory(plist, (xmlChar **) & XML_content, &length);
	ret = iphone_lckd_send(control, XML_content, length, &bytes);

	xmlFree(XML_content);
	xmlFreeDoc(plist);
	plist = NULL;
	ret = iphone_lckd_recv(control, &XML_content, &bytes);

	plist = xmlReadMemory(XML_content, bytes, NULL, NULL, 0);
	if (!plist)
		return IPHONE_E_PLIST_ERROR;
	dict = xmlDocGetRootElement(plist);
	for (dict = dict->children; dict; dict = dict->next) {
		if (!xmlStrcmp(dict->name, "dict"))
			break;
	}
	if (!dict)
		return IPHONE_E_DICT_ERROR;
	dictionary = read_dict_element_strings(dict);
	xmlFreeDoc(plist);
	free(XML_content);

	for (i = 0; dictionary[i]; i += 2) {
		if (!strcmp(dictionary[i], "Result") && !strcmp(dictionary[i + 1], "Success")) {
			log_debug_msg("lockdownd_hello(): success\n");
			ret = IPHONE_E_SUCCESS;
			break;
		}
	}

	free_dictionary(dictionary);
	return ret;
}

/** Generic function to handle simple (key, value) requests.
 *
 * @param control an initialized lockdownd client.
 * @param key the key to request
 * @param value a pointer to the requested value
 *
 * @return IPHONE_E_SUCCESS on success.
 */
iphone_error_t lockdownd_generic_get_value(iphone_lckd_client_t control, char *req_key, char *req_string, char **value)
{
	if (!control || !req_key || !value || (value && *value))
		return IPHONE_E_INVALID_ARG;
	xmlDocPtr plist = new_plist();
	xmlNode *dict = NULL;
	xmlNode *key = NULL;;
	char **dictionary = NULL;
	int bytes = 0, i = 0;
	char *XML_content = NULL;
	uint32 length = 0;
	iphone_error_t ret = IPHONE_E_UNKNOWN_ERROR;

	/* Setup DevicePublicKey request plist */
	dict = add_child_to_plist(plist, "dict", "\n", NULL, 0);
	key = add_key_str_dict_element(plist, dict, req_key, req_string, 1);
	key = add_key_str_dict_element(plist, dict, "Request", "GetValue", 1);
	xmlDocDumpMemory(plist, (xmlChar **) & XML_content, &length);

	/* send to iPhone */
	ret = iphone_lckd_send(control, XML_content, length, &bytes);

	xmlFree(XML_content);
	xmlFreeDoc(plist);
	plist = NULL;

	if (ret != IPHONE_E_SUCCESS)
		return ret;

	/* Now get iPhone's answer */
	ret = iphone_lckd_recv(control, &XML_content, &bytes);

	if (ret != IPHONE_E_SUCCESS)
		return ret;

	plist = xmlReadMemory(XML_content, bytes, NULL, NULL, 0);
	if (!plist)
		return IPHONE_E_PLIST_ERROR;
	dict = xmlDocGetRootElement(plist);
	for (dict = dict->children; dict; dict = dict->next) {
		if (!xmlStrcmp(dict->name, "dict"))
			break;
	}
	if (!dict)
		return IPHONE_E_DICT_ERROR;

	/* Parse xml to check success and to find public key */
	dictionary = read_dict_element_strings(dict);
	xmlFreeDoc(plist);
	free(XML_content);

	int success = 0;
	for (i = 0; dictionary[i]; i += 2) {
		if (!strcmp(dictionary[i], "Result") && !strcmp(dictionary[i + 1], "Success")) {
			success = 1;
		}
		if (!strcmp(dictionary[i], "Value")) {
			*value = strdup(dictionary[i + 1]);
		}
	}

	if (dictionary) {
		free_dictionary(dictionary);
		dictionary = NULL;
	}
	if (success)
		ret = IPHONE_E_SUCCESS;
	return ret;
}

/** Askes for the device's unique id. Part of the lockdownd handshake.
 *
 * @note You most likely want lockdownd_init unless you are doing something special.
 *
 * @return 1 on success and 0 on failure.
 */
iphone_error_t lockdownd_get_device_uid(iphone_lckd_client_t control, char **uid)
{
	return lockdownd_generic_get_value(control, "Key", "UniqueDeviceID", uid);
}

/** Askes for the device's public key. Part of the lockdownd handshake.
 *
 * @note You most likely want lockdownd_init unless you are doing something special.
 *
 * @return 1 on success and 0 on failure.
 */
iphone_error_t lockdownd_get_device_public_key(iphone_lckd_client_t control, char **public_key)
{
	return lockdownd_generic_get_value(control, "Key", "DevicePublicKey", public_key);
}

/** Completes the entire lockdownd handshake.
 *
 * @param phone The iPhone
 * @param lockdownd_client The pointer to the location of the lockdownd_client
 *
 * @return 1 on success and 0 on failure
 */
iphone_error_t iphone_lckd_new_client(iphone_device_t device, iphone_lckd_client_t * client)
{
	if (!device || !client || (client && *client))
		return IPHONE_E_INVALID_ARG;
	iphone_error_t ret = IPHONE_E_SUCCESS;
	char *host_id = NULL;

	iphone_lckd_client_t client_loc = new_lockdownd_client(device);
	if (IPHONE_E_SUCCESS != lockdownd_hello(client_loc)) {
		fprintf(stderr, "Hello failed in the lockdownd client.\n");
		ret = IPHONE_E_NOT_ENOUGH_DATA;
	}


	char *uid = NULL;
	ret = lockdownd_get_device_uid(client_loc, &uid);
	if (IPHONE_E_SUCCESS != ret) {
		fprintf(stderr, "Device refused to send uid.\n");
	}

	host_id = get_host_id();
	if (IPHONE_E_SUCCESS == ret && !host_id) {
		fprintf(stderr, "No HostID found, run libiphone-initconf.\n");
		ret = IPHONE_E_INVALID_CONF;
	}

	if (IPHONE_E_SUCCESS == ret && !is_device_known(uid))
		ret = lockdownd_pair_device(client_loc, uid, host_id);

	if (uid) {
		free(uid);
		uid = NULL;
	}

	ret = lockdownd_start_SSL_session(client_loc, host_id);
	if (IPHONE_E_SUCCESS != ret) {
		ret = IPHONE_E_SSL_ERROR;
		fprintf(stderr, "SSL Session opening failed.\n");
	}

	if (host_id) {
		free(host_id);
		host_id = NULL;
	}

	if (IPHONE_E_SUCCESS == ret)
		*client = client_loc;
	return ret;
}

/** Generates the appropriate keys and pairs the device. It's part of the
 *  lockdownd handshake.
 *
 * @note You most likely want lockdownd_init unless you are doing something special.
 *
 * @return 1 on success and 0 on failure
 */
iphone_error_t lockdownd_pair_device(iphone_lckd_client_t control, char *uid, char *host_id)
{
	iphone_error_t ret = IPHONE_E_UNKNOWN_ERROR;
	xmlDocPtr plist = new_plist();
	xmlNode *dict = NULL;
	xmlNode *dictRecord = NULL;
	char **dictionary = NULL;
	int bytes = 0, i = 0;
	char *XML_content = NULL;
	uint32 length = 0;

	char *device_cert_b64 = NULL;
	char *host_cert_b64 = NULL;
	char *root_cert_b64 = NULL;
	char *public_key_b64 = NULL;

	ret = lockdownd_get_device_public_key(control, &public_key_b64);
	if (ret != IPHONE_E_SUCCESS) {
		fprintf(stderr, "Device refused to send public key.\n");
		return ret;
	}

	ret = lockdownd_gen_pair_cert(public_key_b64, &device_cert_b64, &host_cert_b64, &root_cert_b64);
	if (ret != IPHONE_E_SUCCESS) {
		free(public_key_b64);
		return ret;
	}

	/* Setup Pair request plist */
	dict = add_child_to_plist(plist, "dict", "\n", NULL, 0);
	dictRecord = add_key_dict_node(plist, dict, "PairRecord", "\n", 1);
	//dictRecord = add_child_to_plist(plist, "dict", "\n", NULL, 1);
	add_key_data_dict_element(plist, dictRecord, "DeviceCertificate", device_cert_b64, 2);
	add_key_data_dict_element(plist, dictRecord, "HostCertificate", host_cert_b64, 2);
	add_key_str_dict_element(plist, dictRecord, "HostID", host_id, 2);
	add_key_data_dict_element(plist, dictRecord, "RootCertificate", root_cert_b64, 2);
	add_key_str_dict_element(plist, dict, "Request", "Pair", 1);

	xmlDocDumpMemory(plist, (xmlChar **) & XML_content, &length);

	printf("XML Pairing request : %s\n", XML_content);

	/* send to iPhone */
	ret = iphone_lckd_send(control, XML_content, length, &bytes);

	xmlFree(XML_content);
	xmlFreeDoc(plist);
	plist = NULL;

	if (ret != IPHONE_E_SUCCESS)
		return ret;

	/* Now get iPhone's answer */
	ret = iphone_lckd_recv(control, &XML_content, &bytes);

	if (ret != IPHONE_E_SUCCESS)
		return ret;

	log_debug_msg("lockdown_pair_device: iPhone's response to our pair request:\n");
	log_debug_msg(XML_content);
	log_debug_msg("\n\n");

	plist = xmlReadMemory(XML_content, bytes, NULL, NULL, 0);
	if (!plist) {
		free(public_key_b64);
		return IPHONE_E_PLIST_ERROR;
	}
	dict = xmlDocGetRootElement(plist);
	for (dict = dict->children; dict; dict = dict->next) {
		if (!xmlStrcmp(dict->name, "dict"))
			break;
	}
	if (!dict) {
		free(public_key_b64);
		return IPHONE_E_DICT_ERROR;
	}

	/* Parse xml to check success and to find public key */
	dictionary = read_dict_element_strings(dict);
	xmlFreeDoc(plist);
	free(XML_content);

	int success = 0;
	for (i = 0; dictionary[i]; i += 2) {
		if (!strcmp(dictionary[i], "Result") && !strcmp(dictionary[i + 1], "Success")) {
			success = 1;
		}
	}

	if (dictionary) {
		free_dictionary(dictionary);
		dictionary = NULL;
	}

	/* store public key in config if pairing succeeded */
	if (success) {
		log_debug_msg("lockdownd_pair_device: pair success\n");
		store_device_public_key(uid, public_key_b64);
		ret = IPHONE_E_SUCCESS;
	} else {
		log_debug_msg("lockdownd_pair_device: pair failure\n");
		ret = IPHONE_E_PAIRING_FAILED;
	}
	free(public_key_b64);
	return ret;
}

/** Generates the device certificate from the public key as well as the host
 *  and root certificates.
 * 
 * @return IPHONE_E_SUCCESS on success.
 */
iphone_error_t lockdownd_gen_pair_cert(char *public_key_b64, char **device_cert_b64, char **host_cert_b64,
									   char **root_cert_b64)
{
	if (!public_key_b64 || !device_cert_b64 || !host_cert_b64 || !root_cert_b64)
		return IPHONE_E_INVALID_ARG;
	iphone_error_t ret = IPHONE_E_UNKNOWN_ERROR;

	gnutls_datum_t modulus = { NULL, 0 };
	gnutls_datum_t exponent = { NULL, 0 };

	/* first decode base64 public_key */
	gnutls_datum_t pem_pub_key;
	gsize decoded_size;
	pem_pub_key.data = g_base64_decode(public_key_b64, &decoded_size);
	pem_pub_key.size = decoded_size;

	/* now decode the PEM encoded key */
	gnutls_datum_t der_pub_key;
	if (GNUTLS_E_SUCCESS == gnutls_pem_base64_decode_alloc("RSA PUBLIC KEY", &pem_pub_key, &der_pub_key)) {

		/* initalize asn.1 parser */
		ASN1_TYPE pkcs1 = ASN1_TYPE_EMPTY;
		if (ASN1_SUCCESS == asn1_array2tree(pkcs1_asn1_tab, &pkcs1, NULL)) {

			ASN1_TYPE asn1_pub_key = ASN1_TYPE_EMPTY;
			asn1_create_element(pkcs1, "PKCS1.RSAPublicKey", &asn1_pub_key);

			if (ASN1_SUCCESS == asn1_der_decoding(&asn1_pub_key, der_pub_key.data, der_pub_key.size, NULL)) {

				/* get size to read */
				int ret1 = asn1_read_value(asn1_pub_key, "modulus", NULL, &modulus.size);
				int ret2 = asn1_read_value(asn1_pub_key, "publicExponent", NULL, &exponent.size);

				modulus.data = gnutls_malloc(modulus.size);
				exponent.data = gnutls_malloc(exponent.size);

				ret1 = asn1_read_value(asn1_pub_key, "modulus", modulus.data, &modulus.size);
				ret2 = asn1_read_value(asn1_pub_key, "publicExponent", exponent.data, &exponent.size);
				if (ASN1_SUCCESS == ret1 && ASN1_SUCCESS == ret2)
					ret = IPHONE_E_SUCCESS;
			}
			if (asn1_pub_key)
				asn1_delete_structure(&asn1_pub_key);
		}
		if (pkcs1)
			asn1_delete_structure(&pkcs1);
	}

	/* now generate certifcates */
	if (IPHONE_E_SUCCESS == ret && 0 != modulus.size && 0 != exponent.size) {

		gnutls_global_init();
		gnutls_datum_t essentially_null = { strdup("abababababababab"), strlen("abababababababab") };

		gnutls_x509_privkey_t fake_privkey, root_privkey;
		gnutls_x509_crt_t dev_cert, root_cert, host_cert;

		gnutls_x509_privkey_init(&fake_privkey);
		gnutls_x509_crt_init(&dev_cert);
		gnutls_x509_crt_init(&root_cert);
		gnutls_x509_crt_init(&host_cert);

		if (GNUTLS_E_SUCCESS ==
			gnutls_x509_privkey_import_rsa_raw(fake_privkey, &modulus, &exponent, &essentially_null, &essentially_null,
											   &essentially_null, &essentially_null)) {

			gnutls_x509_privkey_init(&root_privkey);

			/* get root cert */
			gnutls_datum_t pem_root_cert = { NULL, 0 };
			get_root_certificate(&pem_root_cert);
			if (GNUTLS_E_SUCCESS != gnutls_x509_crt_import(root_cert, &pem_root_cert, GNUTLS_X509_FMT_PEM))
				ret = IPHONE_E_SSL_ERROR;

			/* get host cert */
			gnutls_datum_t pem_host_cert = { NULL, 0 };
			get_host_certificate(&pem_host_cert);
			if (GNUTLS_E_SUCCESS != gnutls_x509_crt_import(host_cert, &pem_host_cert, GNUTLS_X509_FMT_PEM))
				ret = IPHONE_E_SSL_ERROR;

			/* get root private key */
			gnutls_datum_t pem_root_priv = { NULL, 0 };
			get_root_private_key(&pem_root_priv);
			if (GNUTLS_E_SUCCESS != gnutls_x509_privkey_import(root_privkey, &pem_root_priv, GNUTLS_X509_FMT_PEM))
				ret = IPHONE_E_SSL_ERROR;

			/* generate device certificate */
			gnutls_x509_crt_set_key(dev_cert, fake_privkey);
			gnutls_x509_crt_set_serial(dev_cert, "\x00", 1);
			gnutls_x509_crt_set_version(dev_cert, 3);
			gnutls_x509_crt_set_ca_status(dev_cert, 0);
			gnutls_x509_crt_set_activation_time(dev_cert, time(NULL));
			gnutls_x509_crt_set_expiration_time(dev_cert, time(NULL) + (60 * 60 * 24 * 365 * 10));
			gnutls_x509_crt_sign(dev_cert, root_cert, root_privkey);

			if (IPHONE_E_SUCCESS == ret) {
				/* if everything went well, export in PEM format */
				gnutls_datum_t dev_pem = { NULL, 0 };
				gnutls_x509_crt_export(dev_cert, GNUTLS_X509_FMT_PEM, NULL, &dev_pem.size);
				dev_pem.data = gnutls_malloc(dev_pem.size);
				gnutls_x509_crt_export(dev_cert, GNUTLS_X509_FMT_PEM, dev_pem.data, &dev_pem.size);

				/* now encode certificates for output */
				*device_cert_b64 = g_base64_encode(dev_pem.data, dev_pem.size);
				*host_cert_b64 = g_base64_encode(pem_host_cert.data, pem_host_cert.size);
				*root_cert_b64 = g_base64_encode(pem_root_cert.data, pem_root_cert.size);
			}
			gnutls_free(pem_root_priv.data);
			gnutls_free(pem_root_cert.data);
			gnutls_free(pem_host_cert.data);
		}
	}

	gnutls_free(modulus.data);
	gnutls_free(exponent.data);

	gnutls_free(der_pub_key.data);
	g_free(pem_pub_key.data);

	return ret;
}

/** Starts SSL communication with lockdownd after the iPhone has been paired.
 *
 * @param control The lockdownd client
 * @param HostID The HostID used with this phone
 *
 * @return 1 on success and 0 on failure
 */
iphone_error_t lockdownd_start_SSL_session(iphone_lckd_client_t control, const char *HostID)
{
	xmlDocPtr plist = new_plist();
	xmlNode *dict = add_child_to_plist(plist, "dict", "\n", NULL, 0);
	xmlNode *key;
	char *what2send = NULL, **dictionary = NULL;
	uint32 len = 0, bytes = 0, return_me = 0, i = 0;
	iphone_error_t ret = IPHONE_E_UNKNOWN_ERROR;
	// end variables

	key = add_key_str_dict_element(plist, dict, "HostID", HostID, 1);
	if (!key) {
		log_debug_msg("Couldn't add a key.\n");
		xmlFreeDoc(plist);
		return IPHONE_E_DICT_ERROR;
	}
	key = add_key_str_dict_element(plist, dict, "Request", "StartSession", 1);
	if (!key) {
		log_debug_msg("Couldn't add a key.\n");
		xmlFreeDoc(plist);
		return IPHONE_E_DICT_ERROR;
	}

	xmlDocDumpMemory(plist, (xmlChar **) & what2send, &len);
	ret = iphone_lckd_send(control, what2send, len, &bytes);

	xmlFree(what2send);
	xmlFreeDoc(plist);

	if (ret != IPHONE_E_SUCCESS)
		return ret;

	if (bytes > 0) {
		ret = iphone_lckd_recv(control, &what2send, &len);
		plist = xmlReadMemory(what2send, len, NULL, NULL, 0);
		dict = xmlDocGetRootElement(plist);
		if (!dict)
			return IPHONE_E_DICT_ERROR;
		for (dict = dict->children; dict; dict = dict->next) {
			if (!xmlStrcmp(dict->name, "dict"))
				break;
		}
		dictionary = read_dict_element_strings(dict);
		xmlFreeDoc(plist);
		free(what2send);
		for (i = 0; dictionary[i]; i += 2) {
			if (!strcmp(dictionary[i], "Result") && !strcmp(dictionary[i + 1], "Success")) {
				// Set up GnuTLS...
				//gnutls_anon_client_credentials_t anoncred;
				gnutls_certificate_credentials_t xcred;

				log_debug_msg("We started the session OK, now trying GnuTLS\n");
				errno = 0;
				gnutls_global_init();
				//gnutls_anon_allocate_client_credentials(&anoncred);
				gnutls_certificate_allocate_credentials(&xcred);
				gnutls_certificate_set_x509_trust_file(xcred, "hostcert.pem", GNUTLS_X509_FMT_PEM);
				gnutls_init(control->ssl_session, GNUTLS_CLIENT);
				{
					int protocol_priority[16] = { GNUTLS_SSL3, 0 };
					int kx_priority[16] = { GNUTLS_KX_ANON_DH, GNUTLS_KX_RSA, 0 };
					int cipher_priority[16] = { GNUTLS_CIPHER_AES_128_CBC, GNUTLS_CIPHER_AES_256_CBC, 0 };
					int mac_priority[16] = { GNUTLS_MAC_SHA1, GNUTLS_MAC_MD5, 0 };
					int comp_priority[16] = { GNUTLS_COMP_NULL, 0 };

					gnutls_cipher_set_priority(*control->ssl_session, cipher_priority);
					gnutls_compression_set_priority(*control->ssl_session, comp_priority);
					gnutls_kx_set_priority(*control->ssl_session, kx_priority);
					gnutls_protocol_set_priority(*control->ssl_session, protocol_priority);
					gnutls_mac_set_priority(*control->ssl_session, mac_priority);

				}
				gnutls_credentials_set(*control->ssl_session, GNUTLS_CRD_CERTIFICATE, xcred);	// this part is killing me.

				log_debug_msg("GnuTLS step 1...\n");
				gnutls_transport_set_ptr(*control->ssl_session, (gnutls_transport_ptr_t) control);
				log_debug_msg("GnuTLS step 2...\n");
				gnutls_transport_set_push_function(*control->ssl_session, (gnutls_push_func) & lockdownd_secuwrite);
				log_debug_msg("GnuTLS step 3...\n");
				gnutls_transport_set_pull_function(*control->ssl_session, (gnutls_pull_func) & lockdownd_securead);
				log_debug_msg("GnuTLS step 4 -- now handshaking...\n");

				if (errno)
					log_debug_msg("WARN: errno says %s before handshake!\n", strerror(errno));
				return_me = gnutls_handshake(*control->ssl_session);
				log_debug_msg("GnuTLS handshake done...\n");

				free_dictionary(dictionary);

				if (return_me != GNUTLS_E_SUCCESS) {
					log_debug_msg("GnuTLS reported something wrong.\n");
					gnutls_perror(return_me);
					log_debug_msg("oh.. errno says %s\n", strerror(errno));
					return IPHONE_E_SSL_ERROR;
				} else {
					control->in_SSL = 1;
					return IPHONE_E_SUCCESS;
				}
			}
		}

		log_debug_msg("Apparently failed negotiating with lockdownd.\n");
		log_debug_msg("Responding dictionary: \n");
		for (i = 0; dictionary[i]; i += 2) {
			log_debug_msg("\t%s: %s\n", dictionary[i], dictionary[i + 1]);
		}


		free_dictionary(dictionary);
		return IPHONE_E_SSL_ERROR;
	} else {
		log_debug_msg("Didn't get enough bytes.\n");
		return IPHONE_E_NOT_ENOUGH_DATA;
	}
}

/** gnutls callback for writing data to the iPhone.
 *
 * @param transport It's really the lockdownd client, but the method signature has to match
 * @param buffer The data to send
 * @param length The length of data to send in bytes
 *
 * @return The number of bytes sent
 */
ssize_t lockdownd_secuwrite(gnutls_transport_ptr_t transport, char *buffer, size_t length)
{
	int bytes = 0;
	iphone_lckd_client_t control;
	control = (iphone_lckd_client_t) transport;
	log_debug_msg("lockdownd_secuwrite() called\n");
	log_debug_msg("pre-send\nlength = %zi\n", length);
	iphone_mux_send(control->connection, buffer, length, &bytes);
	log_debug_msg("post-send\nsent %i bytes\n", bytes);

	dump_debug_buffer("sslpacketwrite.out", buffer, length);
	return bytes;
}

/** gnutls callback for reading data from the iPhone
 *
 * @param transport It's really the lockdownd client, but the method signature has to match
 * @param buffer The buffer to store data in
 * @param length The length of data to read in bytes
 *
 * @return The number of bytes read
 */
ssize_t lockdownd_securead(gnutls_transport_ptr_t transport, char *buffer, size_t length)
{
	int bytes = 0, pos_start_fill = 0;
	char *hackhackhack = NULL;
	iphone_lckd_client_t control;
	control = (iphone_lckd_client_t) transport;
	log_debug_msg("lockdownd_securead() called\nlength = %zi\n", length);
	// Buffering hack! Throw what we've got in our "buffer" into the stream first, then get more.
	if (control->gtls_buffer_hack_len > 0) {
		if (length > control->gtls_buffer_hack_len) {	// If it's asking for more than we got
			length -= control->gtls_buffer_hack_len;	// Subtract what we have from their requested length
			pos_start_fill = control->gtls_buffer_hack_len;	// set the pos to start filling at
			memcpy(buffer, control->gtls_buffer_hack, control->gtls_buffer_hack_len);	// Fill their buffer partially
			free(control->gtls_buffer_hack);	// free our memory, it's not chained anymore
			control->gtls_buffer_hack_len = 0;	// we don't have a hack buffer anymore
			log_debug_msg("Did a partial fill to help quench thirst for data\n");
		} else if (length < control->gtls_buffer_hack_len) {	// If it's asking for less...
			control->gtls_buffer_hack_len -= length;	// subtract what they're asking for
			memcpy(buffer, control->gtls_buffer_hack, length);	// fill their buffer
			hackhackhack = (char *) malloc(sizeof(char) * control->gtls_buffer_hack_len);	// strndup is NOT a good solution -- concatenates \0!!!! Anyway, make a new "hack" buffer.
			memcpy(hackhackhack, control->gtls_buffer_hack + length, control->gtls_buffer_hack_len);	// Move what's left into the new one
			free(control->gtls_buffer_hack);	// Free the old one
			control->gtls_buffer_hack = hackhackhack;	// And make it the new one.
			hackhackhack = NULL;
			log_debug_msg("Quenched the thirst for data; new hack length is %i\n", control->gtls_buffer_hack_len);
			return length;		// hand it over.
		} else {				// length == hack length
			memcpy(buffer, control->gtls_buffer_hack, length);	// copy our buffer into theirs
			free(control->gtls_buffer_hack);	// free our "obligation"
			control->gtls_buffer_hack_len = 0;	// free our "obligation"
			log_debug_msg("Satiated the thirst for data; now we have to eventually receive again.\n");
			return length;		// hand it over
		}
	}
	// End buffering hack!
	char *recv_buffer = (char *) malloc(sizeof(char) * (length * 1000));	// ensuring nothing stupid happens

	log_debug_msg("pre-read\nclient wants %zi bytes\n", length);
	iphone_mux_recv(control->connection, recv_buffer, (length * 1000), &bytes);
	log_debug_msg("post-read\nwe got %i bytes\n", bytes);
	if (bytes < 0) {
		log_debug_msg("lockdownd_securead(): uh oh\n");
		log_debug_msg
			("I believe what we have here is a failure to communicate... libusb says %s but strerror says %s\n",
			 usb_strerror(), strerror(errno));
		return bytes + 28;		// an errno
	}
	if (bytes >= length) {
		if (bytes > length) {
			log_debug_msg
				("lockdownd_securead: Client deliberately read less data than was there; resorting to GnuTLS buffering hack.\n");
			if (!control->gtls_buffer_hack_len) {	// if there's no hack buffer yet
				//control->gtls_buffer_hack = strndup(recv_buffer+length, bytes-length); // strndup is NOT a good solution!
				control->gtls_buffer_hack_len += bytes - length;
				control->gtls_buffer_hack = (char *) malloc(sizeof(char) * control->gtls_buffer_hack_len);
				memcpy(control->gtls_buffer_hack, recv_buffer + length, control->gtls_buffer_hack_len);
			} else {			// if there is. 
				control->gtls_buffer_hack =
					realloc(control->gtls_buffer_hack, control->gtls_buffer_hack_len + (bytes - length));
				memcpy(control->gtls_buffer_hack + control->gtls_buffer_hack_len, recv_buffer + length, bytes - length);
				control->gtls_buffer_hack_len += bytes - length;
			}
		}
		memcpy(buffer + pos_start_fill, recv_buffer, length);
		free(recv_buffer);
		if (bytes == length) {
			log_debug_msg("Returning how much we received.\n");
			return bytes;
		} else {
			log_debug_msg("Returning what they want to hear.\nHack length: %i\n", control->gtls_buffer_hack_len);
			return length;
		}
	}
	return bytes;
}

/** Command to start the desired service
 *
 * @param control The lockdownd client
 * @param service The name of the service to start
 *
 * @return The port number the service was started on or 0 on failure.
 */
iphone_error_t iphone_lckd_start_service(iphone_lckd_client_t client, const char *service, int *port)
{
	if (!client || !service || !port)
		return IPHONE_E_INVALID_ARG;

	char *host_id = get_host_id();
	if (!host_id)
		return IPHONE_E_INVALID_CONF;
	if (!client->in_SSL && !lockdownd_start_SSL_session(client, host_id))
		return IPHONE_E_SSL_ERROR;

	char *XML_query, **dictionary;
	uint32 length, i = 0, port_loc = 0, bytes = 0;
	uint8 result = 0;
	iphone_error_t ret = IPHONE_E_UNKNOWN_ERROR;

	free(host_id);
	host_id = NULL;

	xmlDocPtr plist = new_plist();
	xmlNode *dict = add_child_to_plist(plist, "dict", "\n", NULL, 0);
	xmlNode *key;
	key = add_key_str_dict_element(plist, dict, "Request", "StartService", 1);
	if (!key) {
		xmlFreeDoc(plist);
		return IPHONE_E_UNKNOWN_ERROR;
	}
	key = add_key_str_dict_element(plist, dict, "Service", service, 1);
	if (!key) {
		xmlFreeDoc(plist);
		return IPHONE_E_UNKNOWN_ERROR;
	}

	xmlDocDumpMemory(plist, (xmlChar **) & XML_query, &length);

	ret = iphone_lckd_send(client, XML_query, length, &bytes);
	free(XML_query);
	if (IPHONE_E_SUCCESS != ret)
		return ret;

	ret = iphone_lckd_recv(client, &XML_query, &bytes);
	xmlFreeDoc(plist);
	if (IPHONE_E_SUCCESS != ret)
		return ret;

	if (bytes <= 0)
		return IPHONE_E_NOT_ENOUGH_DATA;
	else {
		plist = xmlReadMemory(XML_query, bytes, NULL, NULL, 0);
		if (!plist)
			return IPHONE_E_UNKNOWN_ERROR;
		dict = xmlDocGetRootElement(plist);
		if (!dict)
			return IPHONE_E_UNKNOWN_ERROR;
		for (dict = dict->children; dict; dict = dict->next) {
			if (!xmlStrcmp(dict->name, "dict"))
				break;
		}

		if (!dict)
			return IPHONE_E_UNKNOWN_ERROR;
		dictionary = read_dict_element_strings(dict);

		for (i = 0; dictionary[i]; i += 2) {
			log_debug_msg("lockdownd_start_service() dictionary %s: %s\n", dictionary[i], dictionary[i + 1]);

			if (!xmlStrcmp(dictionary[i], "Port")) {
				port_loc = atoi(dictionary[i + 1]);
				log_debug_msg("lockdownd_start_service() atoi'd port: %i\n", port);
			}

			if (!xmlStrcmp(dictionary[i], "Result")) {
				if (!xmlStrcmp(dictionary[i + 1], "Success")) {
					result = 1;
				}
			}
		}

		log_debug_msg("lockdownd_start_service(): DATA RECEIVED:\n\n");
		log_debug_msg(XML_query);
		log_debug_msg("end data received by lockdownd_start_service()\n");

		free(XML_query);
		xmlFreeDoc(plist);
		free_dictionary(dictionary);
		if (port && result) {
			*port = port_loc;
			return IPHONE_E_SUCCESS;
		} else
			return IPHONE_E_UNKNOWN_ERROR;
	}

	return IPHONE_E_UNKNOWN_ERROR;
}