linux/net
Pablo Neira Ayuso 8ca3f5e974 netfilter: conntrack: fix race between confirmation and flush
Commit 5195c14c8b ("netfilter: conntrack: fix race in
__nf_conntrack_confirm against get_next_corpse") aimed to resolve the
race condition between the confirmation (packet path) and the flush
command (from control plane). However, it introduced a crash when
several packets race to add a new conntrack, which seems easier to
reproduce when nf_queue is in place.

Fix this race, in __nf_conntrack_confirm(), by removing the CT
from unconfirmed list before checking the DYING bit. In case
race occured, re-add the CT to the dying list

This patch also changes the verdict from NF_ACCEPT to NF_DROP when
we lose race. Basically, the confirmation happens for the first packet
that we see in a flow. If you just invoked conntrack -F once (which
should be the common case), then this is likely to be the first packet
of the flow (unless you already called flush anytime soon in the past).
This should be hard to trigger, but better drop this packet, otherwise
we leave things in inconsistent state since the destination will likely
reply to this packet, but it will find no conntrack, unless the origin
retransmits.

The change of the verdict has been discussed in:
https://www.marc.info/?l=linux-netdev&m=141588039530056&w=2

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-01-06 22:27:45 +01:00
..
6lowpan net/6lowpan: Remove FSF address from GPL statement. 2014-12-05 12:43:04 +01:00
9p 9p/trans_virtio: enable VQs early 2014-10-15 10:25:04 +10:30
802 net: set name_assign_type in alloc_netdev() 2014-07-15 16:12:48 -07:00
8021q vlan: Add ability to always enable TSO/UFO 2014-12-12 10:58:53 -05:00
appletalk new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
atm put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
ax25 new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
batman-adv batman-adv: replace strnicmp with strncasecmp 2014-10-14 02:18:24 +02:00
bluetooth Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next 2014-12-15 13:23:09 -05:00
bridge Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 2014-12-05 20:56:46 -08:00
caif put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
can can: fix spelling errors 2014-12-07 21:22:05 +01:00
ceph libceph: change from BUG to WARN for __remove_osd() asserts 2014-11-13 22:26:34 +03:00
core net: Disallow providing non zero VLAN ID for NIC drivers FDB add flow 2014-12-16 15:41:19 -05:00
dcb dcbnl : Disable software interrupts before taking dcb_lock 2014-11-16 14:50:52 -05:00
dccp net: introduce helper macro for_each_cmsghdr 2014-12-10 22:41:55 -05:00
decnet new helper: memcpy_to_msg() 2014-11-24 04:28:51 -05:00
dns_resolver Merge commit 'v3.16' into next 2014-10-01 00:44:04 +10:00
dsa Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
ethernet net: Add function for parsing the header length out of linear ethernet frames 2014-09-05 17:47:02 -07:00
hsr net/hsr: Remove left-over never-true conditional code. 2014-07-11 15:04:40 -07:00
ieee802154 Merge tag 'master-2014-12-08' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next 2014-12-09 18:12:03 -05:00
ipv4 netfilter: nf_tables: fix port natting in little endian archs 2014-12-23 15:34:28 +01:00
ipv6 netfilter: nf_tables: fix port natting in little endian archs 2014-12-23 15:34:28 +01:00
ipx switch ipxrtr_route_packet() from iovec to msghdr 2014-11-24 04:28:49 -05:00
irda irda: Convert function pointer arrays and uses to const 2014-12-10 15:33:16 -05:00
iucv net: introduce helper macro for_each_cmsghdr 2014-12-10 22:41:55 -05:00
key new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
l2tp ip_generic_getfrag, udplite_getfrag: switch to passing msghdr 2014-12-09 16:28:22 -05:00
lapb lapb: move EXPORT_SYMBOL after functions. 2014-10-24 15:51:42 -04:00
llc llc: Make llc_sap_action_t function pointer arrays const 2014-12-10 15:21:24 -05:00
mac80211 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless 2014-12-08 13:58:58 -05:00
mac802154 mac802154: use goto label on failure 2014-12-05 14:18:42 +01:00
mpls net: Remove MPLS GSO feature. 2014-11-05 23:52:33 -08:00
netfilter netfilter: conntrack: fix race between confirmation and flush 2015-01-06 22:27:45 +01:00
netlabel netlabel: kernel-doc warning fix 2014-10-09 01:40:05 -04:00
netlink netlink: Don't reorder loads/stores before marking mmap netlink frame as available 2014-12-18 12:35:55 -05:00
netrom new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
nfc Merge tag 'master-2014-12-08' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next 2014-12-09 18:12:03 -05:00
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-12-10 15:48:20 -05:00
packet Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-12-11 14:27:06 -08:00
phonet new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
rds rds: Fix min() warning in rds_message_inc_copy_to_user() 2014-12-15 11:49:09 -05:00
rfkill Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
rose new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
rxrpc net: introduce helper macro for_each_cmsghdr 2014-12-10 22:41:55 -05:00
sched Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-12-10 15:48:20 -05:00
sctp net: introduce helper macro for_each_cmsghdr 2014-12-10 22:41:55 -05:00
sunrpc NFS client updates for Linux 3.19 2014-12-10 15:13:13 -08:00
switchdev bridge: call netdev_sw_port_stp_update when bridge port STP status changes 2014-12-02 20:01:22 -08:00
tipc tipc: fix broadcast wakeup contention after congestion 2014-12-10 14:45:33 -05:00
unix put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
vmw_vsock put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
wimax wimax: convert printk to pr_foo() 2014-10-07 20:28:44 -04:00
wireless cfg80211: remove unneeded initialisations in nl80211_set_reg 2014-11-28 14:54:31 +01:00
x25 new helper: memcpy_from_msg() 2014-11-24 04:28:48 -05:00
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2014-12-08 21:30:21 -05:00
compat.c put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
Kconfig net: introduce generic switch devices support 2014-12-02 20:01:20 -08:00
Makefile net: introduce generic switch devices support 2014-12-02 20:01:20 -08:00
nonet.c
socket.c put iov_iter into msghdr 2014-12-09 16:29:03 -05:00
sysctl_net.c