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wlantest: Decrypt EAPOL-Key 3/4 Key Data

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This commit is contained in:
Jouni Malinen 2010-11-09 00:39:43 +02:00
parent 43882f1efc
commit 8672562b04
1 changed files with 112 additions and 2 deletions
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114
wlantest/rx_data.c
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@ -15,6 +15,8 @@
#include "utils/includes.h"
#include "utils/common.h"
#include "crypto/aes_wrap.h"
#include "crypto/crypto.h"
#include "common/ieee802_11_defs.h"
#include "common/eapol_common.h"
#include "common/wpa_common.h"
@ -177,6 +179,77 @@ static void rx_data_eapol_key_2_of_4(struct wlantest *wt, const u8 *dst,
}
static u8 * decrypt_eapol_key_data_rc4(const u8 *kek,
const struct wpa_eapol_key *hdr,
size_t *len)
{
u8 ek[32], *buf;
u16 keydatalen = WPA_GET_BE16(hdr->key_data_length);
buf = os_malloc(keydatalen);
if (buf == NULL)
return NULL;
os_memcpy(ek, hdr->key_iv, 16);
os_memcpy(ek + 16, kek, 16);
os_memcpy(buf, hdr + 1, keydatalen);
if (rc4_skip(ek, 32, 256, buf, keydatalen)) {
wpa_printf(MSG_INFO, "RC4 failed");
os_free(buf);
return NULL;
}
*len = keydatalen;
return buf;
}
static u8 * decrypt_eapol_key_data_aes(const u8 *kek,
const struct wpa_eapol_key *hdr,
size_t *len)
{
u8 *buf;
u16 keydatalen = WPA_GET_BE16(hdr->key_data_length);
if (keydatalen % 8) {
wpa_printf(MSG_INFO, "Unsupported AES-WRAP len %d",
keydatalen);
return NULL;
}
keydatalen -= 8; /* AES-WRAP adds 8 bytes */
buf = os_malloc(keydatalen);
if (buf == NULL)
return NULL;
if (aes_unwrap(kek, keydatalen / 8, (u8 *) (hdr + 1), buf)) {
os_free(buf);
wpa_printf(MSG_INFO, "AES unwrap failed - "
"could not decrypt EAPOL-Key key data");
return NULL;
}
*len = keydatalen;
return buf;
}
static u8 * decrypt_eapol_key_data(const u8 *kek, u16 ver,
const struct wpa_eapol_key *hdr,
size_t *len)
{
switch (ver) {
case WPA_KEY_INFO_TYPE_HMAC_MD5_RC4:
return decrypt_eapol_key_data_rc4(kek, hdr, len);
case WPA_KEY_INFO_TYPE_HMAC_SHA1_AES:
case WPA_KEY_INFO_TYPE_AES_128_CMAC:
return decrypt_eapol_key_data_aes(kek, hdr, len);
default:
wpa_printf(MSG_INFO, "Unsupported EAPOL-Key Key Descriptor "
"Version %u", ver);
return NULL;
}
}
static void rx_data_eapol_key_3_of_4(struct wlantest *wt, const u8 *dst,
const u8 *src, const u8 *data, size_t len)
{
@ -184,8 +257,11 @@ static void rx_data_eapol_key_3_of_4(struct wlantest *wt, const u8 *dst,
struct wlantest_sta *sta;
const struct ieee802_1x_hdr *eapol;
const struct wpa_eapol_key *hdr;
const u8 *key_data;
int recalc = 0;
u16 key_info;
u16 key_info, ver, key_data_len;
u8 *decrypted;
size_t decrypted_len = 0;
wpa_printf(MSG_DEBUG, "EAPOL-Key 3/4 " MACSTR " -> " MACSTR,
MAC2STR(src), MAC2STR(dst));
@ -199,6 +275,8 @@ static void rx_data_eapol_key_3_of_4(struct wlantest *wt, const u8 *dst,
eapol = (const struct ieee802_1x_hdr *) data;
hdr = (const struct wpa_eapol_key *) (eapol + 1);
key_info = WPA_GET_BE16(hdr->key_info);
key_data_len = WPA_GET_BE16(hdr->key_data_length);
if (os_memcmp(sta->anonce, hdr->key_nonce, WPA_NONCE_LEN) != 0) {
wpa_printf(MSG_INFO, "EAPOL-Key ANonce mismatch between 1/4 "
"and 3/4");
@ -222,7 +300,23 @@ static void rx_data_eapol_key_3_of_4(struct wlantest *wt, const u8 *dst,
}
wpa_printf(MSG_DEBUG, "Valid MIC found in EAPOL-Key 3/4");
/* TODO: decrypt Key Data and store GTK, IGTK */
key_data = (const u8 *) (hdr + 1);
/* TODO: handle WPA without EncrKeyData bit */
if (!(key_info & WPA_KEY_INFO_ENCR_KEY_DATA)) {
wpa_printf(MSG_INFO, "EAPOL-Key 3/4 without EncrKeyData bit");
return;
}
ver = key_info & WPA_KEY_INFO_TYPE_MASK;
decrypted = decrypt_eapol_key_data(sta->ptk.kek, ver, hdr,
&decrypted_len);
if (decrypted == NULL) {
wpa_printf(MSG_INFO, "Failed to decrypt EAPOL-Key Key Data");
return;
}
wpa_hexdump(MSG_DEBUG, "Decrypted EAPOL-Key Key Data",
decrypted, decrypted_len);
/* TODO: parse KDEs and store GTK, IGTK */
os_free(decrypted);
}
@ -285,6 +379,7 @@ static void rx_data_eapol_key(struct wlantest *wt, const u8 *dst,
{
const struct ieee802_1x_hdr *eapol;
const struct wpa_eapol_key *hdr;
const u8 *key_data;
u16 key_info, key_length, ver, key_data_length;
eapol = (const struct ieee802_1x_hdr *) data;
@ -313,6 +408,19 @@ static void rx_data_eapol_key(struct wlantest *wt, const u8 *dst,
key_info = WPA_GET_BE16(hdr->key_info);
key_length = WPA_GET_BE16(hdr->key_length);
key_data_length = WPA_GET_BE16(hdr->key_data_length);
key_data = (const u8 *) (hdr + 1);
if (key_data + key_data_length > data + len) {
wpa_printf(MSG_INFO, "Truncated EAPOL-Key from " MACSTR,
MAC2STR(src));
return;
}
if (key_data + key_data_length < data + len) {
wpa_hexdump(MSG_DEBUG, "Extra data after EAPOL-Key Key Data "
"field", key_data + key_data_length,
data + len - key_data - key_data_length);
}
ver = key_info & WPA_KEY_INFO_TYPE_MASK;
wpa_printf(MSG_DEBUG, "EAPOL-Key ver=%u %c idx=%u%s%s%s%s%s%s%s%s "
"datalen=%u",
@ -347,6 +455,8 @@ static void rx_data_eapol_key(struct wlantest *wt, const u8 *dst,
hdr->key_nonce, WPA_KEY_RSC_LEN);
wpa_hexdump(MSG_MSGDUMP, "EAPOL-Key Key MIC",
hdr->key_mic, 16);
wpa_hexdump(MSG_MSGDUMP, "EAPOL-Key Key Data",
key_data, key_data_length);
if (key_info & (WPA_KEY_INFO_ERROR | WPA_KEY_INFO_REQUEST))
return;