diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_proto_tcp.c')
| -rw-r--r-- | net/netfilter/nf_conntrack_proto_tcp.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index a63b51dceaf2..a634c72b1ffc 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -655,6 +655,37 @@ static bool tcp_in_window(struct nf_conn *ct, tn->tcp_be_liberal) res = true; if (!res) { + bool seq_ok = before(seq, sender->td_maxend + 1); + + if (!seq_ok) { + u32 overshot = end - sender->td_maxend + 1; + bool ack_ok; + + ack_ok = after(sack, receiver->td_end - MAXACKWINDOW(sender) - 1); + + if (in_recv_win && + ack_ok && + overshot <= receiver->td_maxwin && + before(sack, receiver->td_end + 1)) { + /* Work around TCPs that send more bytes than allowed by + * the receive window. + * + * If the (marked as invalid) packet is allowed to pass by + * the ruleset and the peer acks this data, then its possible + * all future packets will trigger 'ACK is over upper bound' check. + * + * Thus if only the sequence check fails then do update td_end so + * possible ACK for this data can update internal state. + */ + sender->td_end = end; + sender->flags |= IP_CT_TCP_FLAG_DATA_UNACKNOWLEDGED; + + nf_ct_l4proto_log_invalid(skb, ct, hook_state, + "%u bytes more than expected", overshot); + return res; + } + } + nf_ct_l4proto_log_invalid(skb, ct, hook_state, "%s", before(seq, sender->td_maxend + 1) ? |