linux/net
Jesper Dangaard Brouer b3cad287d1 conntrack: RFC5961 challenge ACK confuse conntrack LAST-ACK transition
In compliance with RFC5961, the network stack send challenge ACK in
response to spurious SYN packets, since commit 0c228e833c ("tcp:
Restore RFC5961-compliant behavior for SYN packets").

This pose a problem for netfilter conntrack in state LAST_ACK, because
this challenge ACK is (falsely) seen as ACKing last FIN, causing a
false state transition (into TIME_WAIT).

The challenge ACK is hard to distinguish from real last ACK.  Thus,
solution introduce a flag that tracks the potential for seeing a
challenge ACK, in case a SYN packet is let through and current state
is LAST_ACK.

When conntrack transition LAST_ACK to TIME_WAIT happens, this flag is
used for determining if we are expecting a challenge ACK.

Scapy based reproducer script avail here:
 https://github.com/netoptimizer/network-testing/blob/master/scapy/tcp_hacks_3WHS_LAST_ACK.py

Fixes: 0c228e833c ("tcp: Restore RFC5961-compliant behavior for SYN packets")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-05-15 20:50:56 +02:00
..
6lowpan
9p 9p: patches for 4.1 merge window 2015-04-18 17:45:30 -04:00
802 net: Kill dev_rebuild_header 2015-03-02 16:43:41 -05:00
8021q vlan: implement ndo_get_iflink 2015-04-02 14:05:00 -04:00
appletalk appletalk: Use eth_<foo>_addr instead of memset 2015-03-03 17:01:37 -05:00
atm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-04-15 09:00:47 -07:00
ax25 ax25: Fix the build when CONFIG_INET is disabled 2015-03-05 13:17:39 -05:00
batman-adv dev: introduce dev_get_iflink() 2015-04-02 14:04:59 -04:00
bluetooth Bluetooth: hidp: Fix regression with older userspace and flags validation 2015-04-18 11:01:08 -04:00
bridge netfilter: nf_tables: switch registers to 32 bit addressing 2015-04-13 17:17:29 +02:00
caif Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-03-20 18:51:09 -04:00
can can: introduce new raw socket option to join the given CAN filters 2015-04-01 11:28:22 +02:00
ceph crush: straw2 bucket type with an efficient 64-bit crush_ln() 2015-04-22 18:33:43 +03:00
core net: rfs: fix crash in get_rps_cpus() 2015-04-26 16:07:57 -04:00
dcb net/dcb: Add IEEE QCN attribute 2015-03-06 21:50:02 -05:00
dccp inet: fix possible panic in reqsk_queue_unlink() 2015-04-24 11:39:15 -04:00
decnet netfilter: Pass socket pointer down through okfn(). 2015-04-07 15:25:55 -04:00
dns_resolver
dsa net: dsa: use DEVICE_ATTR_RW to declare temp1_max 2015-04-17 15:58:37 -04:00
ethernet ethernet: Use eth_<foo>_addr instead of memset 2015-03-03 17:01:38 -05:00
hsr net/hsr: Fix NULL pointer dereference and refcnt bugs when deleting a HSR interface. 2015-03-01 13:40:23 -05:00
ieee802154 ieee802154: don't export static symbol 2015-03-14 17:11:31 +01:00
ipv4 inet: fix possible panic in reqsk_queue_unlink() 2015-04-24 11:39:15 -04:00
ipv6 inet: fix possible panic in reqsk_queue_unlink() 2015-04-24 11:39:15 -04:00
ipx net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
irda Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-03-09 23:38:02 -04:00
iucv Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-04-02 16:16:53 -04:00
key xfrm: simplify xfrm_address_t use 2015-03-31 13:58:35 -04:00
l2tp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-04-06 22:34:15 -04:00
lapb
llc net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
mac80211 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-04-15 09:00:47 -07:00
mac802154 mac802154: cleanup concurrent check 2015-03-27 19:18:50 +01:00
mpls mpls: Prevent use of implicit NULL label as outgoing label 2015-04-22 14:24:54 -04:00
netfilter conntrack: RFC5961 challenge ACK confuse conntrack LAST-ACK transition 2015-05-15 20:50:56 +02:00
netlabel netlink: implement nla_put_in_addr and nla_put_in6_addr 2015-03-31 13:58:35 -04:00
netlink net: fix crash in build_skb() 2015-04-25 15:49:49 -04:00
netrom net: Kill dev_rebuild_header 2015-03-02 16:43:41 -05:00
nfc nfc: Fix portid type in urelease_work 2015-04-13 16:35:16 -04:00
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-04-15 09:00:47 -07:00
packet af_packet: pass checksum validation status to the user 2015-03-23 22:01:28 -04:00
phonet net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
rds Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-04-14 15:44:14 -04:00
rfkill
rose net: Kill dev_rebuild_header 2015-03-02 16:43:41 -05:00
rxrpc new helper: msg_data_left() 2015-04-11 15:53:35 -04:00
sched act_mirred: Fix bogus header when redirecting from VLAN 2015-04-17 13:29:28 -04:00
sctp sctp: avoid to repeatedly declare external variables 2015-03-25 11:40:16 -04:00
sunrpc NFS client updates for Linux 4.1 2015-04-26 17:33:59 -07:00
switchdev switchdev: fix stp update API to work with layered netdevices 2015-03-23 16:44:56 -04:00
tipc tipc: fix node refcount issue 2015-04-23 11:50:34 -04:00
unix Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-04-27 14:05:19 -07:00
vmw_vsock net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
wimax
wireless cfg80211: don't allow disabling WEXT if it's required 2015-04-08 09:19:29 +02:00
x25 net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
xfrm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-04-14 15:44:14 -04:00
compat.c net: switch importing msghdr from userland to {compat_,}import_iovec() 2015-04-09 00:02:26 -04:00
Kconfig
Makefile mpls: Refactor how the mpls module is built 2015-03-04 00:26:06 -05:00
socket.c VFS: net/: d_inode() annotations 2015-04-15 15:06:56 -04:00
sysctl_net.c