On Tue, 2013-08-27 at 13:24 -0700, Phil Oester wrote: > In commit 90ba9b19 (tcp: tcp_make_synack() can use alloc_skb()), Eric changed > the call to sock_wmalloc in tcp_make_synack to alloc_skb. In doing so, > the netfilter owner match lost its ability to block the SYNACK packet on > outbound listening sockets. For example: > > [phil@f19_main ~]$ id > uid=1000(phil) gid=1000(phil) groups=1000(phil) > > [phil@f19_main ~]$ sudo iptables -A OUTPUT -p tcp -m owner --uid-owner 1000 -j REJECT > Oh well. > [phil@f19_main ~]$ echo hi | nc -l -p 8888 > > Before this commit, attempting to connect to the port 8888 listener generated > this: > > 10.10.10.1.47457 > 10.10.10.110.8888: Flags [S], seq 1855270582 [...] > 10.10.10.110 > 10.10.10.110: ICMP 10.10.10.1 tcp port 47457 unreachable, length 68 > Hmm... I think TCP stack should send more SYNACK, no ? It sounds more logical to block the incoming SYN, but whatever. > After this commit, the session is established but the first packet of the > session gets rejected: > > 10.10.10.1.47453 > 10.10.10.110.8888: Flags [S], seq 2089355862 [...] > 10.10.10.110.8888 > 10.10.10.1.47453: Flags [S.], seq 2554257713, ack 2089355863 [...] > 10.10.10.1.47453 > 10.10.10.110.8888: Flags [.], ack 1, win 115 [...] > 10.10.10.110 > 10.10.10.110: ICMP 10.10.10.1 tcp port 47453 unreachable, length 63 > > Reverting 90ba9b19 (and adjusting for the removal of s_data_desired) fixes the > problem. Is there a better way to do this? Well, a revert seems OK to me, it was not a critical change. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
