wlantest: Update PTK after rekeying even if EAPOL-Key msg 4/4 is missing

Update TPTK to PTK if a valid EAPOL-Key msg 2/4 and 3/4 are available,
but 4/4 is missing. This avoids certain cases where the new TK could be
derived, but it was not being used to try to decrypt following encrypted
frames.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

diff --git a/wlantest/rx_data.c b/wlantest/rx_data.c
index 58c986d8358c42a225bd6fc6a37d6a26c81b7bdd..fa8df77beeeec0e7d02e85f16ddea0cdfa613a3e 100644 (file)
--- a/wlantest/rx_data.c
+++ b/wlantest/rx_data.c
@@ -330,6 +330,26 @@ skip_replay_det:
 }
 
 
+static u8 * try_ptk_decrypt(struct wlantest *wt, struct wlantest_sta *sta,
+                           const struct ieee80211_hdr *hdr, int keyid,
+                           const u8 *data, size_t len,
+                           const u8 *tk, size_t tk_len, size_t *dlen)
+{
+       u8 *decrypted = NULL;
+
+       if (sta->pairwise_cipher == WPA_CIPHER_CCMP_256)
+               decrypted = ccmp_256_decrypt(tk, hdr, data, len, dlen);
+       else if (sta->pairwise_cipher == WPA_CIPHER_GCMP ||
+                sta->pairwise_cipher == WPA_CIPHER_GCMP_256)
+               decrypted = gcmp_decrypt(tk, tk_len, hdr, data, len, dlen);
+       else
+               decrypted = ccmp_decrypt(tk, hdr, data, len, dlen);
+       write_decrypted_note(wt, decrypted, tk, tk_len, keyid);
+
+       return decrypted;
+}
+
+
 static void rx_data_bss_prot(struct wlantest *wt,
                             const struct ieee80211_hdr *hdr, size_t hdrlen,
                             const u8 *qos, const u8 *dst, const u8 *src,
@@ -562,18 +582,9 @@ skip_replay_det:
        } else if (sta->pairwise_cipher == WPA_CIPHER_WEP40) {
                decrypted = wep_decrypt(wt, hdr, data, len, &dlen);
        } else if (sta->ptk_set) {
-               if (sta->pairwise_cipher == WPA_CIPHER_CCMP_256)
-                       decrypted = ccmp_256_decrypt(sta->ptk.tk, hdr, data,
-                                                    len, &dlen);
-               else if (sta->pairwise_cipher == WPA_CIPHER_GCMP ||
-                        sta->pairwise_cipher == WPA_CIPHER_GCMP_256)
-                       decrypted = gcmp_decrypt(sta->ptk.tk, sta->ptk.tk_len,
-                                                hdr, data, len, &dlen);
-               else
-                       decrypted = ccmp_decrypt(sta->ptk.tk, hdr, data, len,
-                                                &dlen);
-               write_decrypted_note(wt, decrypted, sta->ptk.tk,
-                                    sta->ptk.tk_len, keyid);
+               decrypted = try_ptk_decrypt(wt, sta, hdr, keyid, data, len,
+                                           sta->ptk.tk, sta->ptk.tk_len,
+                                           &dlen);
        } else {
                decrypted = try_all_ptk(wt, sta->pairwise_cipher, hdr, keyid,
                                        data, len, &dlen);
@@ -620,6 +631,22 @@ check_zero_tk:
                                dlen, 1, peer_addr);
                write_pcap_decrypted(wt, (const u8 *) hdr, hdrlen,
                                     decrypted, dlen);
+       } else if (sta->tptk_set) {
+               /* Check whether TPTK has a matching TK that could be used to
+                * decrypt the frame. That could happen if EAPOL-Key msg 4/4
+                * was missing in the capture and this was PTK rekeying. */
+               decrypted = try_ptk_decrypt(wt, sta, hdr, keyid, data, len,
+                                           sta->tptk.tk, sta->tptk.tk_len,
+                                           &dlen);
+               if (decrypted) {
+                       add_note(wt, MSG_DEBUG,
+                                "Update PTK (rekeying; no valid EAPOL-Key msg 4/4 seen)");
+                       os_memcpy(&sta->ptk, &sta->tptk, sizeof(sta->ptk));
+                       sta->ptk_set = 1;
+                       sta->tptk_set = 0;
+                       os_memset(sta->rsc_tods, 0, sizeof(sta->rsc_tods));
+                       os_memset(sta->rsc_fromds, 0, sizeof(sta->rsc_fromds));
+               }
        } else {
                if (!try_ptk_iter && !only_zero_tk)
                        add_note(wt, MSG_DEBUG, "Failed to decrypt frame");