eap_tls_common.c

一个Linux下无线网卡的设置工具

/*
 * WPA Supplicant / EAP-TLS/PEAP/TTLS/FAST common functions
 * Copyright (c) 2004-2005, Jouni Malinen <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

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

#include "common.h"
#include "eap_i.h"
#include "eap_tls_common.h"
#include "wpa_supplicant.h"
#include "config_ssid.h"
#include "md5.h"
#include "sha1.h"
#include "tls.h"
#include "config.h"


static int eap_tls_check_blob(struct eap_sm *sm, const char **name,
			      const u8 **data, size_t *data_len)
{
	const struct wpa_config_blob *blob;

	if (*name == NULL || strncmp(*name, "blob://", 7) != 0)
		return 0;

	blob = eap_get_config_blob(sm, *name + 7);
	if (blob == NULL) {
		wpa_printf(MSG_ERROR, "%s: Named configuration blob '%s' not "
			   "found", __func__, *name + 7);
		return -1;
	}

	*name = NULL;
	*data = blob->data;
	*data_len = blob->len;

	return 0;
}


int eap_tls_ssl_init(struct eap_sm *sm, struct eap_ssl_data *data,
		     struct wpa_ssid *config)
{
	int ret = -1, res;
	struct tls_connection_params params;

	if (config == NULL)
		return -1;

	data->eap = sm;
	data->phase2 = sm->init_phase2;
	memset(&params, 0, sizeof(params));
	params.engine = config->engine;
	if (data->phase2) {
		params.ca_cert = (char *) config->ca_cert2;
		params.ca_path = (char *) config->ca_path2;
		params.client_cert = (char *) config->client_cert2;
		params.private_key = (char *) config->private_key2;
		params.private_key_passwd =
			(char *) config->private_key2_passwd;
		params.dh_file = (char *) config->dh_file2;
		params.subject_match = (char *) config->subject_match2;
		params.altsubject_match = (char *) config->altsubject_match2;
	} else {
		params.ca_cert = (char *) config->ca_cert;
		params.ca_path = (char *) config->ca_path;
		params.client_cert = (char *) config->client_cert;
		params.private_key = (char *) config->private_key;
		params.private_key_passwd =
			(char *) config->private_key_passwd;
		params.dh_file = (char *) config->dh_file;
		params.subject_match = (char *) config->subject_match;
		params.altsubject_match = (char *) config->altsubject_match;
		params.engine_id = config->engine_id;
		params.pin = config->pin;
		params.key_id = config->key_id;
	}

	if (eap_tls_check_blob(sm, &params.ca_cert, &params.ca_cert_blob,
			       &params.ca_cert_blob_len) ||
	    eap_tls_check_blob(sm, &params.client_cert,
			       &params.client_cert_blob,
			       &params.client_cert_blob_len) ||
	    eap_tls_check_blob(sm, &params.private_key,
			       &params.private_key_blob,
			       &params.private_key_blob_len) ||
	    eap_tls_check_blob(sm, &params.dh_file, &params.dh_blob,
			       &params.dh_blob_len)) {
		wpa_printf(MSG_INFO, "SSL: Failed to get configuration blobs");
		goto done;
	}

	data->conn = tls_connection_init(sm->ssl_ctx);
	if (data->conn == NULL) {
		wpa_printf(MSG_INFO, "SSL: Failed to initialize new TLS "
			   "connection");
		goto done;
	}

	res = tls_connection_set_params(sm->ssl_ctx, data->conn, &params);
	if (res == TLS_SET_PARAMS_ENGINE_PRV_INIT_FAILED) {
		/* At this point with the pkcs11 engine the PIN might be wrong.
		 * We reset the PIN in the configuration to be sure to not use
		 * it again and the calling function must request a new one */
		free(config->pin);
		config->pin = NULL;
	} else if (res == TLS_SET_PARAMS_ENGINE_PRV_VERIFY_FAILED) {
		wpa_printf(MSG_INFO,"TLS: Failed to load private key");
		/* We don't know exactly but maybe the PIN was wrong,
		 * so ask for a new one. */
		free(config->pin);
		config->pin = NULL;
		eap_sm_request_pin(sm, config);
		sm->ignore = TRUE;
		goto done;
	} else if (res) {
		wpa_printf(MSG_INFO, "TLS: Failed to set TLS connection "
			   "parameters");
		goto done;
	}

	/* TODO: make this configurable */
	data->tls_out_limit = 1398;
	if (data->phase2) {
		/* Limit the fragment size in the inner TLS authentication
		 * since the outer authentication with EAP-PEAP does not yet
		 * support fragmentation */
		if (data->tls_out_limit > 100)
			data->tls_out_limit -= 100;
	}

	if (config->phase1 &&
	    strstr(config->phase1, "include_tls_length=1")) {
		wpa_printf(MSG_DEBUG, "TLS: Include TLS Message Length in "
			   "unfragmented packets");
		data->include_tls_length = 1;
	}

	ret = 0;

done:
	return ret;
}


void eap_tls_ssl_deinit(struct eap_sm *sm, struct eap_ssl_data *data)
{
	tls_connection_deinit(sm->ssl_ctx, data->conn);
	free(data->tls_in);
	free(data->tls_out);
}


u8 * eap_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data,
			char *label, size_t len)
{
	struct tls_keys keys;
	u8 *rnd;
	u8 *out;

	if (tls_connection_get_keys(sm->ssl_ctx, data->conn, &keys))
		return NULL;

	if (keys.eap_tls_prf && strcmp(label, "client EAP encryption") == 0) {
		if (len > keys.eap_tls_prf_len)
			return NULL;
		out = malloc(len);
		if (out == NULL)
			return NULL;
		memcpy(out, keys.eap_tls_prf, len);
		return out;
	}

	if (keys.client_random == NULL || keys.server_random == NULL ||
	    keys.master_key == NULL)
		return NULL;

	out = malloc(len);
	rnd = malloc(keys.client_random_len + keys.server_random_len);
	if (out == NULL || rnd == NULL) {
		free(out);
		free(rnd);
		return NULL;
	}
	memcpy(rnd, keys.client_random, keys.client_random_len);
	memcpy(rnd + keys.client_random_len, keys.server_random,
	       keys.server_random_len);

	if (tls_prf(keys.master_key, keys.master_key_len,
		    label, rnd, keys.client_random_len +
		    keys.server_random_len, out, len)) {
		free(rnd);
		free(out);
		return NULL;
	}
	free(rnd);
	return out;
}


/**
 * eap_tls_data_reassemble - Reassemble TLS data
 * @sm: Pointer to EAP state machine allocated with eap_sm_init()
 * @data: Data for TLS processing
 * @in_data: Next incoming TLS segment
 * @in_len: Length of in_data
 * @out_len: Variable for returning output data length
 * @need_more_input: Variable for returning whether more input data is needed
 * to reassemble this TLS packet
 * Returns: Pointer to output data or %NULL on error
 *
 * This function reassembles TLS fragments.
 */
const u8 * eap_tls_data_reassemble(
	struct eap_sm *sm, struct eap_ssl_data *data, const u8 *in_data,
	size_t in_len, size_t *out_len, int *need_more_input)
{
	u8 *buf;

	*need_more_input = 0;

	if (data->tls_in_left > in_len || data->tls_in) {
		if (data->tls_in_len + in_len == 0) {
			free(data->tls_in);
			data->tls_in = NULL;
			data->tls_in_len = 0;
			wpa_printf(MSG_WARNING, "SSL: Invalid reassembly "
				   "state: tls_in_left=%lu tls_in_len=%lu "
				   "in_len=%lu",
				   (unsigned long) data->tls_in_left,
				   (unsigned long) data->tls_in_len,
				   (unsigned long) in_len);
			return NULL;
		}
		buf = realloc(data->tls_in, data->tls_in_len + in_len);
		if (buf == NULL) {
			free(data->tls_in);
			data->tls_in = NULL;
			data->tls_in_len = 0;
			wpa_printf(MSG_INFO, "SSL: Could not allocate memory "
				   "for TLS data");
			return NULL;
		}
		memcpy(buf + data->tls_in_len, in_data, in_len);
		data->tls_in = buf;
		data->tls_in_len += in_len;
		if (in_len > data->tls_in_left) {
			wpa_printf(MSG_INFO, "SSL: more data than TLS message "
				   "length indicated");
			data->tls_in_left = 0;
			return NULL;
		}
		data->tls_in_left -= in_len;
		if (data->tls_in_left > 0) {
			wpa_printf(MSG_DEBUG, "SSL: Need %lu bytes more input "
				   "data", (unsigned long) data->tls_in_left);
			*need_more_input = 1;
			return NULL;
		}
	} else {
		data->tls_in_left = 0;
		data->tls_in = malloc(in_len);
		if (data->tls_in == NULL)
			return NULL;
		memcpy(data->tls_in, in_data, in_len);
		data->tls_in_len = in_len;
	}

	*out_len = data->tls_in_len;
	return data->tls_in;
}


int eap_tls_process_helper(struct eap_sm *sm, struct eap_ssl_data *data,
			   int eap_type, int peap_version,
			   u8 id, const u8 *in_data, size_t in_len,
			   u8 **out_data, size_t *out_len)
{
	size_t len;
	u8 *pos, *flags;
	struct eap_hdr *resp;
	int ret = 0;

	WPA_ASSERT(data->tls_out_len == 0 || in_len == 0);
	*out_len = 0;

	if (data->tls_out_len == 0) {
		/* No more data to send out - expect to receive more data from
		 * the AS. */
		const u8 *msg;
		size_t msg_len;
		int need_more_input;

		msg = eap_tls_data_reassemble(sm, data, in_data, in_len,
					      &msg_len, &need_more_input);
		if (msg == NULL)
			return need_more_input ? 1 : -1;

		/* Full TLS message reassembled - continue handshake processing
		 */
		if (data->tls_out) {
			/* This should not happen.. */
			wpa_printf(MSG_INFO, "SSL: eap_tls_process_helper - "
				   "pending tls_out data even though "
				   "tls_out_len = 0");
			free(data->tls_out);
			WPA_ASSERT(data->tls_out == NULL);
		}
		data->tls_out = tls_connection_handshake(sm->ssl_ctx,
							 data->conn,
							 msg, msg_len,
							 &data->tls_out_len);

		/* Clear reassembled input data (if the buffer was needed). */
		data->tls_in_left = data->tls_in_total = data->tls_in_len = 0;
		free(data->tls_in);
		data->tls_in = NULL;
	}

	if (data->tls_out == NULL) {
		data->tls_out_len = 0;
		return -1;
	}
	if (tls_connection_get_failed(sm->ssl_ctx, data->conn)) {
		wpa_printf(MSG_DEBUG, "SSL: Failed - tls_out available to "
			   "report error");
		ret = -1;
		/* TODO: clean pin if engine used? */
	}

	if (data->tls_out_len == 0) {
		/* TLS negotiation should now be complete since all other cases
		 * needing more that should have been catched above based on
		 * the TLS Message Length field. */
		wpa_printf(MSG_DEBUG, "SSL: No data to be sent out");
		free(data->tls_out);
		data->tls_out = NULL;
		return 1;
	}

	wpa_printf(MSG_DEBUG, "SSL: %lu bytes left to be sent out (of total "
		   "%lu bytes)",
		   (unsigned long) data->tls_out_len - data->tls_out_pos,
		   (unsigned long) data->tls_out_len);
	resp = malloc(sizeof(struct eap_hdr) + 2 + 4 + data->tls_out_limit);
	if (resp == NULL) {
		*out_data = NULL;
		return -1;
	}
	resp->code = EAP_CODE_RESPONSE;
	resp->identifier = id;
	pos = (u8 *) (resp + 1);
	*pos++ = eap_type;
	flags = pos++;
	*flags = peap_version;
	if (data->tls_out_pos == 0 &&
	    (data->tls_out_len > data->tls_out_limit ||
	     data->include_tls_length)) {
		*flags |= EAP_TLS_FLAGS_LENGTH_INCLUDED;
		*pos++ = (data->tls_out_len >> 24) & 0xff;
		*pos++ = (data->tls_out_len >> 16) & 0xff;
		*pos++ = (data->tls_out_len >> 8) & 0xff;
		*pos++ = data->tls_out_len & 0xff;
	}

	len = data->tls_out_len - data->tls_out_pos;
	if (len > data->tls_out_limit) {
		*flags |= EAP_TLS_FLAGS_MORE_FRAGMENTS;
		len = data->tls_out_limit;
		wpa_printf(MSG_DEBUG, "SSL: sending %lu bytes, more fragments "
			   "will follow", (unsigned long) len);
	}
	memcpy(pos, &data->tls_out[data->tls_out_pos], len);
	data->tls_out_pos += len;
	*out_len = (pos - (u8 *) resp) + len;
	resp->length = host_to_be16(*out_len);
	*out_data = (u8 *) resp;

	if (!(*flags & EAP_TLS_FLAGS_MORE_FRAGMENTS)) {
		data->tls_out_len = 0;
		data->tls_out_pos = 0;
		free(data->tls_out);
		data->tls_out = NULL;
	}

	return ret;
}


u8 * eap_tls_build_ack(struct eap_ssl_data *data, size_t *respDataLen, u8 id,
		       int eap_type, int peap_version)
{
	struct eap_hdr *resp;
	u8 *pos;

	*respDataLen = sizeof(struct eap_hdr) + 2;
	resp = malloc(*respDataLen);
	if (resp == NULL)
		return NULL;
	wpa_printf(MSG_DEBUG, "SSL: Building ACK");
	resp->code = EAP_CODE_RESPONSE;
	resp->identifier = id;
	resp->length = host_to_be16(*respDataLen);
	pos = (u8 *) (resp + 1);
	*pos++ = eap_type; /* Type */
	*pos = peap_version; /* Flags */
	return (u8 *) resp;
}


int eap_tls_reauth_init(struct eap_sm *sm, struct eap_ssl_data *data)
{
	free(data->tls_in);
	data->tls_in = NULL;
	data->tls_in_len = data->tls_in_left = data->tls_in_total = 0;
	free(data->tls_out);
	data->tls_out = NULL;
	data->tls_out_len = data->tls_out_pos = 0;

	return tls_connection_shutdown(sm->ssl_ctx, data->conn);
}


int eap_tls_status(struct eap_sm *sm, struct eap_ssl_data *data, char *buf,
		   size_t buflen, int verbose)
{
	char name[128];
	int len = 0;

	if (tls_get_cipher(sm->ssl_ctx, data->conn, name, sizeof(name)) == 0) {
		len += snprintf(buf + len, buflen - len,
				"EAP TLS cipher=%s\n", name);
	}

	return len;
}


const u8 * eap_tls_process_init(struct eap_sm *sm, struct eap_ssl_data *data,
				EapType eap_type, struct eap_method_ret *ret,
				const u8 *reqData, size_t reqDataLen,
				size_t *len, u8 *flags)
{
	const struct eap_hdr *req;
	const u8 *pos;
	size_t left;
	unsigned int tls_msg_len;

	if (tls_get_errors(sm->ssl_ctx)) {
		wpa_printf(MSG_INFO, "SSL: TLS errors detected");
		ret->ignore = TRUE;
		return NULL;
	}

	pos = eap_hdr_validate(eap_type, reqData, reqDataLen, &left);
	if (pos == NULL) {
		ret->ignore = TRUE;
		return NULL;
	}
	req = (const struct eap_hdr *) reqData;
	*flags = *pos++;
	left--;
	wpa_printf(MSG_DEBUG, "SSL: Received packet(len=%lu) - "
		   "Flags 0x%02x", (unsigned long) reqDataLen, *flags);
	if (*flags & EAP_TLS_FLAGS_LENGTH_INCLUDED) {
		if (left < 4) {
			wpa_printf(MSG_INFO, "SSL: Short frame with TLS "
				   "length");
			ret->ignore = TRUE;
			return NULL;
		}
		tls_msg_len = (pos[0] << 24) | (pos[1] << 16) | (pos[2] << 8) |
			pos[3];
		wpa_printf(MSG_DEBUG, "SSL: TLS Message Length: %d",
			   tls_msg_len);
		if (data->tls_in_left == 0) {
			data->tls_in_total = tls_msg_len;
			data->tls_in_left = tls_msg_len;
			free(data->tls_in);
			data->tls_in = NULL;
			data->tls_in_len = 0;
		}
		pos += 4;
		left -= 4;
	}

	ret->ignore = FALSE;
	ret->methodState = METHOD_MAY_CONT;
	ret->decision = DECISION_FAIL;
	ret->allowNotifications = TRUE;

	*len = (size_t) left;
	return pos;
}