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wlantest: TKIP frame reassembly for Michael MIC check in fragmented case

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Reassemble the full MSDU when processing TKIP protected fragmented
frames so that the Michael MIC can be validated once the last fragment
has been received.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
master
Jouni Malinen 3 years ago committed by Jouni Malinen
parent 3332657d69
commit ced15c8ba8
5 changed files with 72 additions and 15 deletions
Show Stats Download Patch File Download Diff File

7
wlantest/rx_data.c
Unescape Escape View File

@ -177,7 +177,8 @@ static u8 * try_ptk(struct wlantest *wt, int pairwise_cipher,
enum michael_mic_result mic_res;
decrypted = tkip_decrypt(ptk->tk, hdr, data, data_len,
decrypted_len, &mic_res);
decrypted_len, &mic_res,
&wt->tkip_frag);
if (decrypted && mic_res == MICHAEL_MIC_INCORRECT)
add_note(wt, MSG_INFO, "Invalid Michael MIC");
else if (decrypted && mic_res == MICHAEL_MIC_NOT_VERIFIED)
@ -328,7 +329,7 @@ skip_replay_det:
enum michael_mic_result mic_res;
decrypted = tkip_decrypt(bss->gtk[keyid], hdr, data, len,
&dlen, &mic_res);
&dlen, &mic_res, &wt->tkip_frag);
if (decrypted && mic_res == MICHAEL_MIC_INCORRECT)
add_note(wt, MSG_INFO, "Invalid Michael MIC");
else if (decrypted && mic_res == MICHAEL_MIC_NOT_VERIFIED)
@ -619,7 +620,7 @@ skip_replay_det:
enum michael_mic_result mic_res;
decrypted = tkip_decrypt(sta->ptk.tk, hdr, data, len, &dlen,
&mic_res);
&mic_res, &wt->tkip_frag);
if (decrypted && mic_res == MICHAEL_MIC_INCORRECT)
add_note(wt, MSG_INFO, "Invalid Michael MIC");
else if (decrypted && mic_res == MICHAEL_MIC_NOT_VERIFIED)

2
wlantest/test_vectors.c
Unescape Escape View File

@ -63,7 +63,7 @@ static void test_vector_tkip(void)
wpa_debug_level = MSG_INFO;
plain = tkip_decrypt(tk, (const struct ieee80211_hdr *) enc,
enc + 24, enc_len - 24, &plain_len, NULL);
enc + 24, enc_len - 24, &plain_len, NULL, NULL);
wpa_debug_level = MSG_EXCESSIVE;
os_free(enc);

64
wlantest/tkip.c
Unescape Escape View File

@ -1,5 +1,5 @@
/*
* Temporal Key Integrity Protocol (CCMP)
* Temporal Key Integrity Protocol (TKIP)
* Copyright (c) 2010, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
@ -291,7 +291,7 @@ static void michael_mic_hdr(const struct ieee80211_hdr *hdr11, u8 *hdr)
u8 * tkip_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
const u8 *data, size_t data_len, size_t *decrypted_len,
enum michael_mic_result *mic_res)
enum michael_mic_result *mic_res, struct tkip_frag *frag)
{
u16 iv16;
u32 iv32;
@ -304,7 +304,11 @@ u8 * tkip_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
u8 michael_hdr[16];
u8 mic[8];
u16 fc = le_to_host16(hdr->frame_control);
const u8 *full_payload;
size_t full_payload_len;
u16 sc = le_to_host16(hdr->seq_ctrl);
u16 sn;
u8 fn;
if (data_len < 8 + 4)
return NULL;
@ -337,10 +341,49 @@ u8 * tkip_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
}
plain_len -= 4;
/* TODO: MSDU reassembly */
if ((fc & WLAN_FC_MOREFRAG) || WLAN_GET_SEQ_FRAG(sc) > 0) {
/* For now, return the decrypted fragment and do not check the
* Michael MIC value in the last fragment */
full_payload = plain;
full_payload_len = plain_len;
sn = WLAN_GET_SEQ_SEQ(sc);
fn = WLAN_GET_SEQ_FRAG(sc);
if (frag) {
/* MSDU reassembly for Michael MIC validation */
if (fn == 0 && (fc & WLAN_FC_MOREFRAG)) {
/* Start of a new fragmented MSDU */
wpabuf_free(frag->buf);
frag->buf = NULL;
frag->buf = wpabuf_alloc_copy(plain, plain_len);
os_memcpy(frag->ra, hdr->addr1, ETH_ALEN);
os_memcpy(frag->ta, hdr->addr2, ETH_ALEN);
frag->sn = sn;
frag->fn = 0;
}
if (frag->buf && (fn || (fc & WLAN_FC_MOREFRAG)) &&
sn == frag->sn && fn == frag->fn + 1 &&
os_memcmp(frag->ra, hdr->addr1, ETH_ALEN) == 0 &&
os_memcmp(frag->ta, hdr->addr2, ETH_ALEN) == 0) {
/* Add the next fragment */
if (wpabuf_resize(&frag->buf, plain_len) == 0) {
wpabuf_put_data(frag->buf, plain, plain_len);
frag->fn = fn;
if (!(fc & WLAN_FC_MOREFRAG)) {
full_payload = wpabuf_head(frag->buf);
full_payload_len =
wpabuf_len(frag->buf);
wpa_hexdump(MSG_MSGDUMP,
"TKIP reassembled full payload",
full_payload,
full_payload_len);
}
}
}
}
if ((fc & WLAN_FC_MOREFRAG) || (fn > 0 && full_payload == plain)) {
/* Return the decrypted fragment and do not check the
* Michael MIC value since no reassembled frame is available. */
*decrypted_len = plain_len;
if (mic_res) {
*mic_res = MICHAEL_MIC_NOT_VERIFIED;
@ -348,7 +391,7 @@ u8 * tkip_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
}
}
if (plain_len < 8) {
if (full_payload_len < 8) {
wpa_printf(MSG_INFO, "TKIP: Not enough room for Michael MIC "
"in a frame from " MACSTR, MAC2STR(hdr->addr2));
os_free(plain);
@ -357,13 +400,14 @@ u8 * tkip_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
michael_mic_hdr(hdr, michael_hdr);
mic_key = tk + ((fc & WLAN_FC_FROMDS) ? 16 : 24);
michael_mic(mic_key, michael_hdr, plain, plain_len - 8, mic);
if (os_memcmp(mic, plain + plain_len - 8, 8) != 0) {
michael_mic(mic_key, michael_hdr, full_payload, full_payload_len - 8,
mic);
if (os_memcmp(mic, full_payload + full_payload_len - 8, 8) != 0) {
wpa_printf(MSG_INFO, "TKIP: Michael MIC mismatch in a frame "
"from " MACSTR, MAC2STR(hdr->addr2));
wpa_hexdump(MSG_DEBUG, "TKIP: Calculated MIC", mic, 8);
wpa_hexdump(MSG_DEBUG, "TKIP: Received MIC",
plain + plain_len - 8, 8);
full_payload + full_payload_len - 8, 8);
if (mic_res) {
*decrypted_len = plain_len - 8;
*mic_res = MICHAEL_MIC_INCORRECT;

2
wlantest/wlantest.c
Unescape Escape View File

@ -110,6 +110,8 @@ static void wlantest_deinit(struct wlantest *wt)
clear_notes(wt);
os_free(wt->decrypted);
wt->decrypted = NULL;
wpabuf_free(wt->tkip_frag.buf);
wt->tkip_frag.buf = NULL;
}

12
wlantest/wlantest.h
Unescape Escape View File

@ -184,6 +184,14 @@ struct wlantest_radius {
#define MAX_CTRL_CONNECTIONS 10
#define MAX_NOTES 10
struct tkip_frag {
struct wpabuf *buf;
u8 ra[ETH_ALEN];
u8 ta[ETH_ALEN];
u16 sn;
u8 fn;
};
struct wlantest {
int monitor_sock;
int monitor_wired;
@ -227,6 +235,8 @@ struct wlantest {
const char *write_file;
const char *pcapng_file;
struct tkip_frag tkip_frag;
};
void add_note(struct wlantest *wt, int level, const char *fmt, ...)
@ -311,7 +321,7 @@ enum michael_mic_result {
};
u8 * tkip_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
const u8 *data, size_t data_len, size_t *decrypted_len,
enum michael_mic_result *mic_res);
enum michael_mic_result *mic_res, struct tkip_frag *frag);
u8 * tkip_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
u8 *pn, int keyid, size_t *encrypted_len);
void tkip_get_pn(u8 *pn, const u8 *data);

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