hostapd/src/wps/wps_attr_process.c

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/*
* Wi-Fi Protected Setup - attribute processing
* Copyright (c) 2008, Jouni Malinen <j@w1.fi>
*
* 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 "includes.h"
#include "common.h"
#include "crypto/sha256.h"
#include "wps_i.h"
int wps_process_authenticator(struct wps_data *wps, const u8 *authenticator,
const struct wpabuf *msg)
{
u8 hash[SHA256_MAC_LEN];
const u8 *addr[2];
size_t len[2];
if (authenticator == NULL) {
wpa_printf(MSG_DEBUG, "WPS: No Authenticator attribute "
"included");
return -1;
}
if (wps->last_msg == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Last message not available for "
"validating authenticator");
return -1;
}
/* Authenticator = HMAC-SHA256_AuthKey(M_prev || M_curr*)
* (M_curr* is M_curr without the Authenticator attribute)
*/
addr[0] = wpabuf_head(wps->last_msg);
len[0] = wpabuf_len(wps->last_msg);
addr[1] = wpabuf_head(msg);
len[1] = wpabuf_len(msg) - 4 - WPS_AUTHENTICATOR_LEN;
hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 2, addr, len, hash);
if (os_memcmp(hash, authenticator, WPS_AUTHENTICATOR_LEN) != 0) {
wpa_printf(MSG_DEBUG, "WPS: Incorrect Authenticator");
return -1;
}
return 0;
}
int wps_process_key_wrap_auth(struct wps_data *wps, struct wpabuf *msg,
const u8 *key_wrap_auth)
{
u8 hash[SHA256_MAC_LEN];
const u8 *head;
size_t len;
if (key_wrap_auth == NULL) {
wpa_printf(MSG_DEBUG, "WPS: No KWA in decrypted attribute");
return -1;
}
head = wpabuf_head(msg);
len = wpabuf_len(msg) - 4 - WPS_KWA_LEN;
if (head + len != key_wrap_auth - 4) {
wpa_printf(MSG_DEBUG, "WPS: KWA not in the end of the "
"decrypted attribute");
return -1;
}
hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, head, len, hash);
if (os_memcmp(hash, key_wrap_auth, WPS_KWA_LEN) != 0) {
wpa_printf(MSG_DEBUG, "WPS: Invalid KWA");
return -1;
}
return 0;
}
static int wps_process_cred_network_idx(struct wps_credential *cred,
const u8 *idx)
{
if (idx == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
"Network Index");
return -1;
}
wpa_printf(MSG_DEBUG, "WPS: Network Index: %d", *idx);
return 0;
}
static int wps_process_cred_ssid(struct wps_credential *cred, const u8 *ssid,
size_t ssid_len)
{
if (ssid == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Credential did not include SSID");
return -1;
}
/* Remove zero-padding since some Registrar implementations seem to use
* hardcoded 32-octet length for this attribute */
while (ssid_len > 0 && ssid[ssid_len - 1] == 0)
ssid_len--;
wpa_hexdump_ascii(MSG_DEBUG, "WPS: SSID", ssid, ssid_len);
if (ssid_len <= sizeof(cred->ssid)) {
os_memcpy(cred->ssid, ssid, ssid_len);
cred->ssid_len = ssid_len;
}
return 0;
}
static int wps_process_cred_auth_type(struct wps_credential *cred,
const u8 *auth_type)
{
if (auth_type == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
"Authentication Type");
return -1;
}
cred->auth_type = WPA_GET_BE16(auth_type);
wpa_printf(MSG_DEBUG, "WPS: Authentication Type: 0x%x",
cred->auth_type);
return 0;
}
static int wps_process_cred_encr_type(struct wps_credential *cred,
const u8 *encr_type)
{
if (encr_type == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
"Encryption Type");
return -1;
}
cred->encr_type = WPA_GET_BE16(encr_type);
wpa_printf(MSG_DEBUG, "WPS: Encryption Type: 0x%x",
cred->encr_type);
return 0;
}
static int wps_process_cred_network_key_idx(struct wps_credential *cred,
const u8 *key_idx)
{
if (key_idx == NULL)
return 0; /* optional attribute */
wpa_printf(MSG_DEBUG, "WPS: Network Key Index: %d", *key_idx);
cred->key_idx = *key_idx;
return 0;
}
static int wps_process_cred_network_key(struct wps_credential *cred,
const u8 *key, size_t key_len)
{
if (key == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
"Network Key");
return -1;
}
wpa_hexdump_key(MSG_DEBUG, "WPS: Network Key", key, key_len);
if (key_len <= sizeof(cred->key)) {
os_memcpy(cred->key, key, key_len);
cred->key_len = key_len;
}
return 0;
}
static int wps_process_cred_mac_addr(struct wps_credential *cred,
const u8 *mac_addr)
{
if (mac_addr == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Credential did not include "
"MAC Address");
return -1;
}
wpa_printf(MSG_DEBUG, "WPS: MAC Address " MACSTR, MAC2STR(mac_addr));
os_memcpy(cred->mac_addr, mac_addr, ETH_ALEN);
return 0;
}
static int wps_process_cred_eap_type(struct wps_credential *cred,
const u8 *eap_type, size_t eap_type_len)
{
if (eap_type == NULL)
return 0; /* optional attribute */
wpa_hexdump(MSG_DEBUG, "WPS: EAP Type", eap_type, eap_type_len);
return 0;
}
static int wps_process_cred_eap_identity(struct wps_credential *cred,
const u8 *identity,
size_t identity_len)
{
if (identity == NULL)
return 0; /* optional attribute */
wpa_hexdump_ascii(MSG_DEBUG, "WPS: EAP Identity",
identity, identity_len);
return 0;
}
static int wps_process_cred_key_prov_auto(struct wps_credential *cred,
const u8 *key_prov_auto)
{
if (key_prov_auto == NULL)
return 0; /* optional attribute */
wpa_printf(MSG_DEBUG, "WPS: Key Provided Automatically: %d",
*key_prov_auto);
return 0;
}
static int wps_process_cred_802_1x_enabled(struct wps_credential *cred,
const u8 *dot1x_enabled)
{
if (dot1x_enabled == NULL)
return 0; /* optional attribute */
wpa_printf(MSG_DEBUG, "WPS: 802.1X Enabled: %d", *dot1x_enabled);
return 0;
}
static void wps_workaround_cred_key(struct wps_credential *cred)
{
if (cred->auth_type & (WPS_AUTH_WPAPSK | WPS_AUTH_WPA2PSK) &&
cred->key_len > 8 && cred->key_len < 64 &&
cred->key[cred->key_len - 1] == 0) {
/*
* A deployed external registrar is known to encode ASCII
* passphrases incorrectly. Remove the extra NULL termination
* to fix the encoding.
*/
wpa_printf(MSG_DEBUG, "WPS: Workaround - remove NULL "
"termination from ASCII passphrase");
cred->key_len--;
}
}
int wps_process_cred(struct wps_parse_attr *attr,
struct wps_credential *cred)
{
wpa_printf(MSG_DEBUG, "WPS: Process Credential");
/* TODO: support multiple Network Keys */
if (wps_process_cred_network_idx(cred, attr->network_idx) ||
wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
wps_process_cred_auth_type(cred, attr->auth_type) ||
wps_process_cred_encr_type(cred, attr->encr_type) ||
wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
wps_process_cred_network_key(cred, attr->network_key,
attr->network_key_len) ||
wps_process_cred_mac_addr(cred, attr->mac_addr) ||
wps_process_cred_eap_type(cred, attr->eap_type,
attr->eap_type_len) ||
wps_process_cred_eap_identity(cred, attr->eap_identity,
attr->eap_identity_len) ||
wps_process_cred_key_prov_auto(cred, attr->key_prov_auto) ||
wps_process_cred_802_1x_enabled(cred, attr->dot1x_enabled))
return -1;
wps_workaround_cred_key(cred);
return 0;
}
int wps_process_ap_settings(struct wps_parse_attr *attr,
struct wps_credential *cred)
{
wpa_printf(MSG_DEBUG, "WPS: Processing AP Settings");
os_memset(cred, 0, sizeof(*cred));
/* TODO: optional attributes New Password and Device Password ID */
if (wps_process_cred_ssid(cred, attr->ssid, attr->ssid_len) ||
wps_process_cred_auth_type(cred, attr->auth_type) ||
wps_process_cred_encr_type(cred, attr->encr_type) ||
wps_process_cred_network_key_idx(cred, attr->network_key_idx) ||
wps_process_cred_network_key(cred, attr->network_key,
attr->network_key_len) ||
wps_process_cred_mac_addr(cred, attr->mac_addr))
return -1;
wps_workaround_cred_key(cred);
return 0;
}