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/*
* Wi-Fi Protected Setup - common functionality
* Copyright (c) 2008-2012, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "crypto/aes_wrap.h"
#include "crypto/crypto.h"
#include "crypto/dh_group5.h"
#include "crypto/sha1.h"
#include "crypto/sha256.h"
#include "crypto/random.h"
#include "wps_i.h"
void wps_kdf(const u8 *key, const u8 *label_prefix, size_t label_prefix_len,
const char *label, u8 *res, size_t res_len)
{
u8 i_buf[4], key_bits[4];
const u8 *addr[4];
size_t len[4];
int i, iter;
u8 hash[SHA256_MAC_LEN], *opos;
size_t left;
WPA_PUT_BE32(key_bits, res_len * 8);
addr[0] = i_buf;
len[0] = sizeof(i_buf);
addr[1] = label_prefix;
len[1] = label_prefix_len;
addr[2] = (const u8 *) label;
len[2] = os_strlen(label);
addr[3] = key_bits;
len[3] = sizeof(key_bits);
iter = (res_len + SHA256_MAC_LEN - 1) / SHA256_MAC_LEN;
opos = res;
left = res_len;
for (i = 1; i <= iter; i++) {
WPA_PUT_BE32(i_buf, i);
hmac_sha256_vector(key, SHA256_MAC_LEN, 4, addr, len, hash);
if (i < iter) {
os_memcpy(opos, hash, SHA256_MAC_LEN);
opos += SHA256_MAC_LEN;
left -= SHA256_MAC_LEN;
} else
os_memcpy(opos, hash, left);
}
}
int wps_derive_keys(struct wps_data *wps)
{
struct wpabuf *pubkey, *dh_shared;
u8 dhkey[SHA256_MAC_LEN], kdk[SHA256_MAC_LEN];
const u8 *addr[3];
size_t len[3];
u8 keys[WPS_AUTHKEY_LEN + WPS_KEYWRAPKEY_LEN + WPS_EMSK_LEN];
if (wps->dh_privkey == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Own DH private key not available");
return -1;
}
pubkey = wps->registrar ? wps->dh_pubkey_e : wps->dh_pubkey_r;
if (pubkey == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Peer DH public key not available");
return -1;
}
wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH Private Key", wps->dh_privkey);
wpa_hexdump_buf(MSG_DEBUG, "WPS: DH peer Public Key", pubkey);
dh_shared = dh5_derive_shared(wps->dh_ctx, pubkey, wps->dh_privkey);
dh5_free(wps->dh_ctx);
wps->dh_ctx = NULL;
dh_shared = wpabuf_zeropad(dh_shared, 192);
if (dh_shared == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Failed to derive DH shared key");
return -1;
}
/* Own DH private key is not needed anymore */
wpabuf_free(wps->dh_privkey);
wps->dh_privkey = NULL;
wpa_hexdump_buf_key(MSG_DEBUG, "WPS: DH shared key", dh_shared);
/* DHKey = SHA-256(g^AB mod p) */
addr[0] = wpabuf_head(dh_shared);
len[0] = wpabuf_len(dh_shared);
sha256_vector(1, addr, len, dhkey);
wpa_hexdump_key(MSG_DEBUG, "WPS: DHKey", dhkey, sizeof(dhkey));
wpabuf_free(dh_shared);
/* KDK = HMAC-SHA-256_DHKey(N1 || EnrolleeMAC || N2) */
addr[0] = wps->nonce_e;
len[0] = WPS_NONCE_LEN;
addr[1] = wps->mac_addr_e;
len[1] = ETH_ALEN;
addr[2] = wps->nonce_r;
len[2] = WPS_NONCE_LEN;
hmac_sha256_vector(dhkey, sizeof(dhkey), 3, addr, len, kdk);
wpa_hexdump_key(MSG_DEBUG, "WPS: KDK", kdk, sizeof(kdk));
wps_kdf(kdk, NULL, 0, "Wi-Fi Easy and Secure Key Derivation",
keys, sizeof(keys));
os_memcpy(wps->authkey, keys, WPS_AUTHKEY_LEN);
os_memcpy(wps->keywrapkey, keys + WPS_AUTHKEY_LEN, WPS_KEYWRAPKEY_LEN);
os_memcpy(wps->emsk, keys + WPS_AUTHKEY_LEN + WPS_KEYWRAPKEY_LEN,
WPS_EMSK_LEN);
wpa_hexdump_key(MSG_DEBUG, "WPS: AuthKey",
wps->authkey, WPS_AUTHKEY_LEN);
wpa_hexdump_key(MSG_DEBUG, "WPS: KeyWrapKey",
wps->keywrapkey, WPS_KEYWRAPKEY_LEN);
wpa_hexdump_key(MSG_DEBUG, "WPS: EMSK", wps->emsk, WPS_EMSK_LEN);
return 0;
}
void wps_derive_psk(struct wps_data *wps, const u8 *dev_passwd,
size_t dev_passwd_len)
{
u8 hash[SHA256_MAC_LEN];
hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN, dev_passwd,
(dev_passwd_len + 1) / 2, hash);
os_memcpy(wps->psk1, hash, WPS_PSK_LEN);
hmac_sha256(wps->authkey, WPS_AUTHKEY_LEN,
dev_passwd + (dev_passwd_len + 1) / 2,
dev_passwd_len / 2, hash);
os_memcpy(wps->psk2, hash, WPS_PSK_LEN);
wpa_hexdump_ascii_key(MSG_DEBUG, "WPS: Device Password",
dev_passwd, dev_passwd_len);
wpa_hexdump_key(MSG_DEBUG, "WPS: PSK1", wps->psk1, WPS_PSK_LEN);
wpa_hexdump_key(MSG_DEBUG, "WPS: PSK2", wps->psk2, WPS_PSK_LEN);
}
struct wpabuf * wps_decrypt_encr_settings(struct wps_data *wps, const u8 *encr,
size_t encr_len)
{
struct wpabuf *decrypted;
const size_t block_size = 16;
size_t i;
u8 pad;
const u8 *pos;
/* AES-128-CBC */
if (encr == NULL || encr_len < 2 * block_size || encr_len % block_size)
{
wpa_printf(MSG_DEBUG, "WPS: No Encrypted Settings received");
return NULL;
}
decrypted = wpabuf_alloc(encr_len - block_size);
if (decrypted == NULL)
return NULL;
wpa_hexdump(MSG_MSGDUMP, "WPS: Encrypted Settings", encr, encr_len);
wpabuf_put_data(decrypted, encr + block_size, encr_len - block_size);
if (aes_128_cbc_decrypt(wps->keywrapkey, encr, wpabuf_mhead(decrypted),
wpabuf_len(decrypted))) {
wpabuf_free(decrypted);
return NULL;
}
wpa_hexdump_buf_key(MSG_MSGDUMP, "WPS: Decrypted Encrypted Settings",
decrypted);
pos = wpabuf_head_u8(decrypted) + wpabuf_len(decrypted) - 1;
pad = *pos;
if (pad > wpabuf_len(decrypted)) {
wpa_printf(MSG_DEBUG, "WPS: Invalid PKCS#5 v2.0 pad value");
wpabuf_free(decrypted);
return NULL;
}
for (i = 0; i < pad; i++) {
if (*pos-- != pad) {
wpa_printf(MSG_DEBUG, "WPS: Invalid PKCS#5 v2.0 pad "
"string");
wpabuf_free(decrypted);
return NULL;
}
}
decrypted->used -= pad;
return decrypted;
}
/**
* wps_pin_checksum - Compute PIN checksum
* @pin: Seven digit PIN (i.e., eight digit PIN without the checksum digit)
* Returns: Checksum digit
*/
unsigned int wps_pin_checksum(unsigned int pin)
{
unsigned int accum = 0;
while (pin) {
accum += 3 * (pin % 10);
pin /= 10;
accum += pin % 10;
pin /= 10;
}
return (10 - accum % 10) % 10;
}
/**
* wps_pin_valid - Check whether a PIN has a valid checksum
* @pin: Eight digit PIN (i.e., including the checksum digit)
* Returns: 1 if checksum digit is valid, or 0 if not
*/
unsigned int wps_pin_valid(unsigned int pin)
{
return wps_pin_checksum(pin / 10) == (pin % 10);
}
/**
* wps_generate_pin - Generate a random PIN
* Returns: Eight digit PIN (i.e., including the checksum digit)
*/
unsigned int wps_generate_pin(void)
{
unsigned int val;
/* Generate seven random digits for the PIN */
if (random_get_bytes((unsigned char *) &val, sizeof(val)) < 0) {
struct os_time now;
os_get_time(&now);
val = os_random() ^ now.sec ^ now.usec;
}
val %= 10000000;
/* Append checksum digit */
return val * 10 + wps_pin_checksum(val);
}
int wps_pin_str_valid(const char *pin)
{
const char *p;
size_t len;
p = pin;
while (*p >= '0' && *p <= '9')
p++;
if (*p != '\0')
return 0;
len = p - pin;
return len == 4 || len == 8;
}
void wps_fail_event(struct wps_context *wps, enum wps_msg_type msg,
u16 config_error, u16 error_indication)
{
union wps_event_data data;
if (wps->event_cb == NULL)
return;
os_memset(&data, 0, sizeof(data));
data.fail.msg = msg;
data.fail.config_error = config_error;
data.fail.error_indication = error_indication;
wps->event_cb(wps->cb_ctx, WPS_EV_FAIL, &data);
}
void wps_success_event(struct wps_context *wps)
{
if (wps->event_cb == NULL)
return;
wps->event_cb(wps->cb_ctx, WPS_EV_SUCCESS, NULL);
}
void wps_pwd_auth_fail_event(struct wps_context *wps, int enrollee, int part)
{
union wps_event_data data;
if (wps->event_cb == NULL)
return;
os_memset(&data, 0, sizeof(data));
data.pwd_auth_fail.enrollee = enrollee;
data.pwd_auth_fail.part = part;
wps->event_cb(wps->cb_ctx, WPS_EV_PWD_AUTH_FAIL, &data);
}
void wps_pbc_overlap_event(struct wps_context *wps)
{
if (wps->event_cb == NULL)
return;
wps->event_cb(wps->cb_ctx, WPS_EV_PBC_OVERLAP, NULL);
}
void wps_pbc_timeout_event(struct wps_context *wps)
{
if (wps->event_cb == NULL)
return;
wps->event_cb(wps->cb_ctx, WPS_EV_PBC_TIMEOUT, NULL);
}
#ifdef CONFIG_WPS_OOB
struct wpabuf * wps_get_oob_cred(struct wps_context *wps)
{
struct wps_data data;
struct wpabuf *plain;
plain = wpabuf_alloc(500);
if (plain == NULL) {
wpa_printf(MSG_ERROR, "WPS: Failed to allocate memory for OOB "
"credential");
return NULL;
}
os_memset(&data, 0, sizeof(data));
data.wps = wps;
data.auth_type = wps->auth_types;
data.encr_type = wps->encr_types;
if (wps_build_version(plain) ||
wps_build_cred(&data, plain) ||
wps_build_wfa_ext(plain, 0, NULL, 0)) {
wpabuf_free(plain);
return NULL;
}
return plain;
}
struct wpabuf * wps_build_nfc_pw_token(u16 dev_pw_id,
const struct wpabuf *pubkey,
const struct wpabuf *dev_pw)
{
struct wpabuf *data;
data = wpabuf_alloc(200);
if (data == NULL)
return NULL;
if (wps_build_version(data) ||
wps_build_oob_dev_pw(data, dev_pw_id, pubkey,
wpabuf_head(dev_pw), wpabuf_len(dev_pw)) ||
wps_build_wfa_ext(data, 0, NULL, 0)) {
wpa_printf(MSG_ERROR, "WPS: Failed to build NFC password "
"token");
wpabuf_free(data);
return NULL;
}
return data;
}
int wps_oob_use_cred(struct wps_context *wps, struct wps_parse_attr *attr)
{
struct wpabuf msg;
size_t i;
for (i = 0; i < attr->num_cred; i++) {
struct wps_credential local_cred;
struct wps_parse_attr cattr;
os_memset(&local_cred, 0, sizeof(local_cred));
wpabuf_set(&msg, attr->cred[i], attr->cred_len[i]);
if (wps_parse_msg(&msg, &cattr) < 0 ||
wps_process_cred(&cattr, &local_cred)) {
wpa_printf(MSG_ERROR, "WPS: Failed to parse OOB "
"credential");
return -1;
}
wps->cred_cb(wps->cb_ctx, &local_cred);
}
return 0;
}
#endif /* CONFIG_WPS_OOB */
int wps_dev_type_str2bin(const char *str, u8 dev_type[WPS_DEV_TYPE_LEN])
{
const char *pos;
/* <categ>-<OUI>-<subcateg> */
WPA_PUT_BE16(dev_type, atoi(str));
pos = os_strchr(str, '-');
if (pos == NULL)
return -1;
pos++;
if (hexstr2bin(pos, &dev_type[2], 4))
return -1;
pos = os_strchr(pos, '-');
if (pos == NULL)
return -1;
pos++;
WPA_PUT_BE16(&dev_type[6], atoi(pos));
return 0;
}
char * wps_dev_type_bin2str(const u8 dev_type[WPS_DEV_TYPE_LEN], char *buf,
size_t buf_len)
{
int ret;
ret = os_snprintf(buf, buf_len, "%u-%08X-%u",
WPA_GET_BE16(dev_type), WPA_GET_BE32(&dev_type[2]),
WPA_GET_BE16(&dev_type[6]));
if (ret < 0 || (unsigned int) ret >= buf_len)
return NULL;
return buf;
}
void uuid_gen_mac_addr(const u8 *mac_addr, u8 *uuid)
{
const u8 *addr[2];
size_t len[2];
u8 hash[SHA1_MAC_LEN];
u8 nsid[16] = {
0x52, 0x64, 0x80, 0xf8,
0xc9, 0x9b,
0x4b, 0xe5,
0xa6, 0x55,
0x58, 0xed, 0x5f, 0x5d, 0x60, 0x84
};
addr[0] = nsid;
len[0] = sizeof(nsid);
addr[1] = mac_addr;
len[1] = 6;
sha1_vector(2, addr, len, hash);
os_memcpy(uuid, hash, 16);
/* Version: 5 = named-based version using SHA-1 */
uuid[6] = (5 << 4) | (uuid[6] & 0x0f);
/* Variant specified in RFC 4122 */
uuid[8] = 0x80 | (uuid[8] & 0x3f);
}
u16 wps_config_methods_str2bin(const char *str)
{
u16 methods = 0;
if (str == NULL) {
/* Default to enabling methods based on build configuration */
methods |= WPS_CONFIG_DISPLAY | WPS_CONFIG_KEYPAD;
#ifdef CONFIG_WPS2
methods |= WPS_CONFIG_VIRT_DISPLAY;
#endif /* CONFIG_WPS2 */
#ifdef CONFIG_WPS_NFC
methods |= WPS_CONFIG_NFC_INTERFACE;
#endif /* CONFIG_WPS_NFC */
} else {
if (os_strstr(str, "ethernet"))
methods |= WPS_CONFIG_ETHERNET;
if (os_strstr(str, "label"))
methods |= WPS_CONFIG_LABEL;
if (os_strstr(str, "display"))
methods |= WPS_CONFIG_DISPLAY;
if (os_strstr(str, "ext_nfc_token"))
methods |= WPS_CONFIG_EXT_NFC_TOKEN;
if (os_strstr(str, "int_nfc_token"))
methods |= WPS_CONFIG_INT_NFC_TOKEN;
if (os_strstr(str, "nfc_interface"))
methods |= WPS_CONFIG_NFC_INTERFACE;
if (os_strstr(str, "push_button"))
methods |= WPS_CONFIG_PUSHBUTTON;
if (os_strstr(str, "keypad"))
methods |= WPS_CONFIG_KEYPAD;
#ifdef CONFIG_WPS2
if (os_strstr(str, "virtual_display"))
methods |= WPS_CONFIG_VIRT_DISPLAY;
if (os_strstr(str, "physical_display"))
methods |= WPS_CONFIG_PHY_DISPLAY;
if (os_strstr(str, "virtual_push_button"))
methods |= WPS_CONFIG_VIRT_PUSHBUTTON;
if (os_strstr(str, "physical_push_button"))
methods |= WPS_CONFIG_PHY_PUSHBUTTON;
#endif /* CONFIG_WPS2 */
}
return methods;
}
struct wpabuf * wps_build_wsc_ack(struct wps_data *wps)
{
struct wpabuf *msg;
wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_ACK");
msg = wpabuf_alloc(1000);
if (msg == NULL)
return NULL;
if (wps_build_version(msg) ||
wps_build_msg_type(msg, WPS_WSC_ACK) ||
wps_build_enrollee_nonce(wps, msg) ||
wps_build_registrar_nonce(wps, msg) ||
wps_build_wfa_ext(msg, 0, NULL, 0)) {
wpabuf_free(msg);
return NULL;
}
return msg;
}
struct wpabuf * wps_build_wsc_nack(struct wps_data *wps)
{
struct wpabuf *msg;
wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_NACK");
msg = wpabuf_alloc(1000);
if (msg == NULL)
return NULL;
if (wps_build_version(msg) ||
wps_build_msg_type(msg, WPS_WSC_NACK) ||
wps_build_enrollee_nonce(wps, msg) ||
wps_build_registrar_nonce(wps, msg) ||
wps_build_config_error(msg, wps->config_error) ||
wps_build_wfa_ext(msg, 0, NULL, 0)) {
wpabuf_free(msg);
return NULL;
}
return msg;
}
#ifdef CONFIG_WPS_NFC
struct wpabuf * wps_nfc_token_gen(int ndef, int *id, struct wpabuf **pubkey,
struct wpabuf **privkey,
struct wpabuf **dev_pw)
{
struct wpabuf *priv = NULL, *pub = NULL, *pw, *ret;
void *dh_ctx;
u16 val;
pw = wpabuf_alloc(WPS_OOB_DEVICE_PASSWORD_LEN);
if (pw == NULL)
return NULL;
if (random_get_bytes(wpabuf_put(pw, WPS_OOB_DEVICE_PASSWORD_LEN),
WPS_OOB_DEVICE_PASSWORD_LEN) ||
random_get_bytes((u8 *) &val, sizeof(val))) {
wpabuf_free(pw);
return NULL;
}
dh_ctx = dh5_init(&priv, &pub);
if (dh_ctx == NULL) {
wpabuf_free(pw);
return NULL;
}
dh5_free(dh_ctx);
*id = 0x10 + val % 0xfff0;
wpabuf_free(*pubkey);
*pubkey = pub;
wpabuf_free(*privkey);
*privkey = priv;
wpabuf_free(*dev_pw);
*dev_pw = pw;
ret = wps_build_nfc_pw_token(*id, *pubkey, *dev_pw);
if (ndef && ret) {
struct wpabuf *tmp;
tmp = ndef_build_wifi(ret);
wpabuf_free(ret);
if (tmp == NULL)
return NULL;
ret = tmp;
}
return ret;
}
#endif /* CONFIG_WPS_NFC */