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wlantest: Try to decrypt frame with zero TK

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If none of the known PTKs have a working TK, check whether an encrypted
frame is encrypted with all zeros TK.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2020-02-28 23:18:59 +02:00
parent 167205d455
commit f5f7286ba5
1 changed files with 48 additions and 21 deletions
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69
wlantest/rx_data.c
View file

@ -132,6 +132,38 @@ static void write_decrypted_note(struct wlantest *wt, const u8 *decrypted,
}
static u8 * try_ptk(int pairwise_cipher, struct wpa_ptk *ptk,
const struct ieee80211_hdr *hdr,
const u8 *data, size_t data_len, size_t *decrypted_len)
{
u8 *decrypted;
unsigned int tk_len = ptk->tk_len;
decrypted = NULL;
if ((pairwise_cipher == WPA_CIPHER_CCMP ||
pairwise_cipher == 0) && tk_len == 16) {
decrypted = ccmp_decrypt(ptk->tk, hdr, data,
data_len, decrypted_len);
} else if ((pairwise_cipher == WPA_CIPHER_CCMP_256 ||
pairwise_cipher == 0) && tk_len == 32) {
decrypted = ccmp_256_decrypt(ptk->tk, hdr, data,
data_len, decrypted_len);
} else if ((pairwise_cipher == WPA_CIPHER_GCMP ||
pairwise_cipher == WPA_CIPHER_GCMP_256 ||
pairwise_cipher == 0) &&
(tk_len == 16 || tk_len == 32)) {
decrypted = gcmp_decrypt(ptk->tk, tk_len, hdr,
data, data_len, decrypted_len);
} else if ((pairwise_cipher == WPA_CIPHER_TKIP ||
pairwise_cipher == 0) && tk_len == 32) {
decrypted = tkip_decrypt(ptk->tk, hdr, data, data_len,
decrypted_len);
}
return decrypted;
}
static u8 * try_all_ptk(struct wlantest *wt, int pairwise_cipher,
const struct ieee80211_hdr *hdr, int keyid,
const u8 *data, size_t data_len, size_t *decrypted_len)
@ -142,27 +174,8 @@ static u8 * try_all_ptk(struct wlantest *wt, int pairwise_cipher,
wpa_debug_level = MSG_WARNING;
dl_list_for_each(ptk, &wt->ptk, struct wlantest_ptk, list) {
unsigned int tk_len = ptk->ptk_len - 32;
decrypted = NULL;
if ((pairwise_cipher == WPA_CIPHER_CCMP ||
pairwise_cipher == 0) && tk_len == 16) {
decrypted = ccmp_decrypt(ptk->ptk.tk, hdr, data,
data_len, decrypted_len);
} else if ((pairwise_cipher == WPA_CIPHER_CCMP_256 ||
pairwise_cipher == 0) && tk_len == 32) {
decrypted = ccmp_256_decrypt(ptk->ptk.tk, hdr, data,
data_len, decrypted_len);
} else if ((pairwise_cipher == WPA_CIPHER_GCMP ||
pairwise_cipher == WPA_CIPHER_GCMP_256 ||
pairwise_cipher == 0) &&
(tk_len == 16 || tk_len == 32)) {
decrypted = gcmp_decrypt(ptk->ptk.tk, tk_len, hdr,
data, data_len, decrypted_len);
} else if ((pairwise_cipher == WPA_CIPHER_TKIP ||
pairwise_cipher == 0) && tk_len == 32) {
decrypted = tkip_decrypt(ptk->ptk.tk, hdr, data,
data_len, decrypted_len);
}
decrypted = try_ptk(pairwise_cipher, &ptk->ptk, hdr,
data, data_len, decrypted_len);
if (decrypted) {
wpa_debug_level = prev_level;
add_note(wt, MSG_DEBUG,
@ -542,6 +555,20 @@ skip_replay_det:
add_note(wt, MSG_DEBUG, "Current PTK did not work, but found a match from all known PTKs");
}
}
if (!decrypted) {
struct wpa_ptk zero_ptk;
os_memset(&zero_ptk, 0, sizeof(zero_ptk));
zero_ptk.tk_len = wpa_cipher_key_len(sta->pairwise_cipher);
decrypted = try_ptk(sta->pairwise_cipher, &zero_ptk, hdr,
data, len, &dlen);
if (decrypted) {
add_note(wt, MSG_DEBUG,
"Frame was encrypted with zero TK");
write_decrypted_note(wt, decrypted, zero_ptk.tk,
zero_ptk.tk_len, keyid);
}
}
if (decrypted) {
u16 fc = le_to_host16(hdr->frame_control);
const u8 *peer_addr = NULL;