Bug #4549
closedTCP reassembly, failed assert app_progress > last_ack_abs, both sides need to be pruned
Description
Found by oss-fuzz
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35626
Minimized reproducer with suricata is./src/suricata -r lolb.pcap -k none -c suricata.yaml --set stream.midstream=true
What happens is
- first packet (midstream) all ok (ack = 1)
- second packet, from the other side, ack is ok, but sequence indicates a gap from first packet ack (seq = 77)
- third packet, sequence ok, ack is increased since first packet confirming the gap (ack = 77) StreamTcpUpdateAppLayerProgress is called by AppLayerHandleTCPData at the end of if (flags & STREAM_GAP) {
- Fourth packet is in first direction (seq and ack meaningless)
At the end of third packet, the 76 gap does not get subtracted in app_progress_rel as StreamTcpPruneSession only considers the other stream
Files