wlantest: Allow duplicate frame processing after decryption failure

If a sniffer capture does not include FCS for each frame, but may
included frames with invalid FCS, it would be possible for wlantest to
try to decrypt the first received frame and fail (e.g., due to CCMP MIC
mismatch) because that particular frame was corrupted and then ignore
the following retry of that frame as a duplicate even if that retry has
different payload (e.g., if its reception did not show corruption).

Work around this by skipping duplicate frame detection immediately
following a decryption failure.

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

wlantest/process.c

@@ -161,7 +161,8 @@ static int rx_duplicate(struct wlantest *wt, const struct ieee80211_hdr *hdr,
 	else
 		seq_ctrl = &sta->seq_ctrl_to_sta[tid];
 
-	if ((fc & WLAN_FC_RETRY) && hdr->seq_ctrl == *seq_ctrl) {
+	if ((fc & WLAN_FC_RETRY) && hdr->seq_ctrl == *seq_ctrl &&
+	    !sta->allow_duplicate) {
 		u16 s = le_to_host16(hdr->seq_ctrl);
 		add_note(wt, MSG_MSGDUMP, "Ignore duplicated frame (seq=%u "
 			 "frag=%u A1=" MACSTR " A2=" MACSTR ")",
@@ -171,6 +172,7 @@ static int rx_duplicate(struct wlantest *wt, const struct ieee80211_hdr *hdr,
 	}
 
 	*seq_ctrl = hdr->seq_ctrl;
+	sta->allow_duplicate = 0;
 
 	return 0;
 }

wlantest/rx_data.c

@@ -485,8 +485,16 @@ skip_replay_det:
 				dlen, 1, peer_addr);
 		write_pcap_decrypted(wt, (const u8 *) hdr, hdrlen,
 				     decrypted, dlen);
-	} else if (!try_ptk_iter)
-		add_note(wt, MSG_DEBUG, "Failed to decrypt frame");
+	} else {
+		if (!try_ptk_iter)
+			add_note(wt, MSG_DEBUG, "Failed to decrypt frame");
+
+		/* Assume the frame was corrupted and there was no FCS to check.
+		 * Allow retry of this particular frame to be processed so that
+		 * it could end up getting decrypted if it was received without
+		 * corruption. */
+		sta->allow_duplicate = 1;
+	}
 	os_free(decrypted);
 }
 

wlantest/rx_mgmt.c

@@ -1315,6 +1315,12 @@ static u8 * mgmt_ccmp_decrypt(struct wlantest *wt, const u8 *data, size_t len,
 			os_memcpy(frame + 24, decrypted, *dlen);
 			*dlen += 24;
 		}
+	} else {
+		/* Assume the frame was corrupted and there was no FCS to check.
+		 * Allow retry of this particular frame to be processed so that
+		 * it could end up getting decrypted if it was received without
+		 * corruption. */
+		sta->allow_duplicate = 1;
 	}
 
 	os_free(decrypted);

wlantest/wlantest.h

@@ -93,6 +93,7 @@ struct wlantest_sta {
 
 	le16 seq_ctrl_to_sta[17];
 	le16 seq_ctrl_to_ap[17];
+	int allow_duplicate;
 
 	int pwrmgt;
 	int pspoll;