AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

netfilter: Validate the sequence number of dataless ACK packets as well

Browse Source 
We spare nothing by not validating the sequence number of dataless
ACK packets and enabling it makes harder off-path attacks.

See: "Reflection scan: an Off-Path Attack on TCP" by Jan Wrobel,
http://arxiv.org/abs/1201.2074

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Jozsef Kadlecsik 2012-08-31 09:55:54 +00:00 committed by Pablo Neira Ayuso
parent 64f509ce71
commit 4a70bbfaef
1 changed files with 2 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
net/netfilter/nf_conntrack_proto_tcp.c
View File

@ -630,15 +630,9 @@ static bool tcp_in_window(const struct nf_conn *ct,
ack = sack = receiver->td_end;
}
if (seq == end
&& (!tcph->rst
|| (seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)))
if (tcph->rst && seq == 0 && state->state == TCP_CONNTRACK_SYN_SENT)
/*
* Packets contains no data: we assume it is valid
* and check the ack value only.
* However RST segments are always validated by their
* SEQ number, except when seq == 0 (reset sent answering
* SYN.
* RST sent answering SYN.
*/
seq = end = sender->td_end;