linux-stable/include/net
Guillaume Nault 04d26e7b15 tcp: fix rejected syncookies due to stale timestamps
If no synflood happens for a long enough period of time, then the
synflood timestamp isn't refreshed and jiffies can advance so much
that time_after32() can't accurately compare them any more.

Therefore, we can end up in a situation where time_after32(now,
last_overflow + HZ) returns false, just because these two values are
too far apart. In that case, the synflood timestamp isn't updated as
it should be, which can trick tcp_synq_no_recent_overflow() into
rejecting valid syncookies.

For example, let's consider the following scenario on a system
with HZ=1000:

  * The synflood timestamp is 0, either because that's the timestamp
    of the last synflood or, more commonly, because we're working with
    a freshly created socket.

  * We receive a new SYN, which triggers synflood protection. Let's say
    that this happens when jiffies == 2147484649 (that is,
    'synflood timestamp' + HZ + 2^31 + 1).

  * Then tcp_synq_overflow() doesn't update the synflood timestamp,
    because time_after32(2147484649, 1000) returns false.
    With:
      - 2147484649: the value of jiffies, aka. 'now'.
      - 1000: the value of 'last_overflow' + HZ.

  * A bit later, we receive the ACK completing the 3WHS. But
    cookie_v[46]_check() rejects it because tcp_synq_no_recent_overflow()
    says that we're not under synflood. That's because
    time_after32(2147484649, 120000) returns false.
    With:
      - 2147484649: the value of jiffies, aka. 'now'.
      - 120000: the value of 'last_overflow' + TCP_SYNCOOKIE_VALID.

    Of course, in reality jiffies would have increased a bit, but this
    condition will last for the next 119 seconds, which is far enough
    to accommodate for jiffie's growth.

Fix this by updating the overflow timestamp whenever jiffies isn't
within the [last_overflow, last_overflow + HZ] range. That shouldn't
have any performance impact since the update still happens at most once
per second.

Now we're guaranteed to have fresh timestamps while under synflood, so
tcp_synq_no_recent_overflow() can safely use it with time_after32() in
such situations.

Stale timestamps can still make tcp_synq_no_recent_overflow() return
the wrong verdict when not under synflood. This will be handled in the
next patch.

For 64 bits architectures, the problem was introduced with the
conversion of ->tw_ts_recent_stamp to 32 bits integer by commit
cca9bab1b7 ("tcp: use monotonic timestamps for PAWS").
The problem has always been there on 32 bits architectures.

Fixes: cca9bab1b7 ("tcp: use monotonic timestamps for PAWS")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-06 21:05:14 -08:00
..
9p treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188 2019-05-30 11:29:21 -07:00
bluetooth Bluetooth: Add support for utilizing Fast Advertising Interval 2019-09-05 17:27:21 +02:00
caif treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 194 2019-05-30 11:29:22 -07:00
iucv net/af_iucv: locate IUCV header via skb_network_header() 2018-09-26 09:56:07 -07:00
netfilter netfilter: nf_tables: constify nft_reg_load{8, 16, 64}() 2019-11-20 11:21:34 -08:00
netns ipv6: keep track of routes using src 2019-11-21 14:45:55 -08:00
nfc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
phonet treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 336 2019-06-05 17:37:07 +02:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-25 14:57:26 -08:00
tc_act net: sched: take reference to psample group in flow_action infra 2019-09-16 09:18:03 +02:00
6lowpan.h
act_api.h net/sched: actions: remove unused 'order' 2019-11-12 12:11:22 -08:00
addrconf.h ipv6: Make ipv6_mc_may_pull() return bool. 2019-10-07 09:37:27 -04:00
af_ieee802154.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
af_rxrpc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
af_unix.h net: split out functions related to registering inflight socket files 2019-02-28 08:24:23 -07:00
af_vsock.h vsock: prevent transport modules unloading 2019-11-14 18:12:18 -08:00
ah.h
arp.h net: avoid potential false sharing in neighbor related code 2019-11-06 16:14:48 -08:00
atmclip.h
ax25.h ax25: fix possible use-after-free 2019-01-23 11:18:00 -08:00
ax88796.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
bond_3ad.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 90 2019-05-24 17:37:53 +02:00
bond_alb.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 5 2019-05-21 11:28:40 +02:00
bond_options.h bonding: add an option to specify a delay between peer notifications 2019-07-04 12:30:48 -07:00
bonding.h bonding: fix state transition issue in link monitoring 2019-11-05 17:40:16 -08:00
bpf_sk_storage.h bpf: support cloning sk storage on accept() 2019-08-17 23:18:54 +02:00
busy_poll.h net: annotate lockless accesses to sk->sk_napi_id 2019-10-30 17:34:35 -07:00
calipso.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
cfg80211-wext.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cfg80211.h mac80211: Implement Airtime-based Queue Limit (AQL) 2019-11-22 13:36:25 +01:00
cfg802154.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
checksum.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cipso_ipv4.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
cls_cgroup.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
codel.h
codel_impl.h
codel_qdisc.h
compat.h net: rework SIOCGSTAMP ioctl handling 2019-04-19 14:07:40 -07:00
datalink.h
dcbevent.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 2019-05-30 11:29:52 -07:00
dcbnl.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 2019-05-30 11:29:52 -07:00
devlink.h Merge branch 'mlx5-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux 2019-11-13 14:24:58 -08:00
dn.h
dn_dev.h
dn_fib.h
dn_neigh.h
dn_nsp.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 24 2019-05-21 11:52:39 +02:00
dn_route.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 24 2019-05-21 11:52:39 +02:00
drop_monitor.h drop_monitor: Add basic infrastructure for hardware drops 2019-08-17 12:40:08 -07:00
dsa.h net: dsa: ocelot: add tagger for Ocelot/Felix switches 2019-11-15 12:32:16 -08:00
dsfield.h
dst.h net: dst.h: Fix shifting signed 32-bit value by 31 bits problem 2019-07-01 10:48:34 -07:00
dst_cache.h
dst_metadata.h
dst_ops.h
erspan.h
esp.h
ethoc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
failover.h
fib_notifier.h net: fib_notifier: propagate extack down to the notifier block callback 2019-10-04 11:10:56 -07:00
fib_rules.h net: fib_notifier: propagate extack down to the notifier block callback 2019-10-04 11:10:56 -07:00
firewire.h
flow.h route: Add multipath_hash in flowi_common to make user-define hash 2019-02-27 12:50:17 -08:00
flow_dissector.h cls_flower: Fix the behavior using port ranges with hw-offload 2019-12-03 11:55:46 -08:00
flow_offload.h net: core: rename indirect block ingress cb function 2019-12-06 20:45:09 -08:00
fou.h
fq.h net/flow_dissector: switch to siphash 2019-10-23 20:13:22 -07:00
fq_impl.h net/fq_impl: Switch to kvmalloc() for memory allocation 2019-11-08 09:11:49 +01:00
garp.h
gen_stats.h net_sched: extend packet counter to 64bit 2019-11-05 18:20:55 -08:00
genetlink.h net: genetlink: remove unused genl_family_attrbuf() 2019-10-06 15:44:47 +02:00
geneve.h net: Move the definition of the default Geneve udp port to public header file 2019-03-22 12:09:31 -07:00
gre.h net: Add netif_is_gretap()/netif_is_ip6gretap() 2018-12-10 15:53:04 -08:00
gro_cells.h
gtp.h
gue.h net:gue.h:Fix shifting signed 32-bit value by 31 bits problem 2019-07-01 10:58:23 -07:00
hwbm.h net: hwbm: if CONFIG_NET_HWBM unset, make stub functions static 2019-10-25 16:24:32 -07:00
icmp.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ieee80211_radiotap.h wireless-drivers-next patches for 5.1 2019-02-22 12:56:24 -08:00
ieee802154_netdev.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
if_inet6.h ipv6: shrink struct ipv6_mc_socklist 2019-08-28 14:43:03 -07:00
ife.h net: ife: drop include of module.h from net/ife.h 2019-04-22 21:50:53 -07:00
ila.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
inet6_connection_sock.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
inet6_hashtables.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
inet_common.h inet: factor out inet_send_prepare() 2019-07-03 13:51:54 -07:00
inet_connection_sock.h net/tls: use RCU protection on icsk->icsk_ulp_data 2019-08-31 23:44:28 -07:00
inet_ecn.h inet: Refactor INET_ECN_decapsulate() 2018-10-17 17:45:07 -07:00
inet_frag.h inet: frags: re-introduce skb coalescing for local delivery 2019-08-08 15:55:10 -07:00
inet_hashtables.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
inet_sock.h ip: support SO_MARK cmsg 2019-09-13 21:44:19 +02:00
inet_timewait_sock.h tcp: honor SO_PRIORITY in TIME_WAIT state 2019-09-27 12:05:02 +02:00
inetpeer.h net: ipv4: use a dedicated counter for icmp_v4 redirect packets 2019-02-08 21:50:15 -08:00
ip.h net: inet_is_local_reserved_port() port arg should be unsigned short 2019-11-26 15:15:07 -08:00
ip6_checksum.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip6_fib.h ipv6: keep track of routes using src 2019-11-21 14:45:55 -08:00
ip6_route.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-27 21:06:39 -07:00
ip6_tunnel.h ip6_tunnel: allow not to count pkts on tstats by passing dev as NULL 2019-06-18 20:48:45 -04:00
ip_fib.h ipv4: move fib4_has_custom_rules() helper to public header 2019-11-21 14:45:55 -08:00
ip_tunnels.h route: Add multipath_hash in flowi_common to make user-define hash 2019-02-27 12:50:17 -08:00
ip_vs.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-02 13:54:56 -07:00
ipcomp.h
ipconfig.h
ipv6.h net: ipv6: add net argument to ip6_dst_lookup_flow 2019-12-04 12:27:12 -08:00
ipv6_frag.h inet: fix various use-after-free in defrags units 2019-06-19 11:37:47 -04:00
ipv6_stubs.h net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup 2019-12-04 12:27:13 -08:00
ipx.h
iw_handler.h
kcm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
l3mdev.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
lag.h
lapb.h
lib80211.h
llc.h llc: avoid blocking in llc_sap_close() 2018-09-13 09:04:58 -07:00
llc_c_ac.h
llc_c_ev.h
llc_c_st.h
llc_conn.h llc: fix sk_buff leak in llc_conn_service() 2019-10-08 13:23:05 -07:00
llc_if.h
llc_pdu.h
llc_s_ac.h
llc_s_ev.h
llc_s_st.h
llc_sap.h
lwtunnel.h lwtunnel: Pass encap and encap type attributes to lwtunnel_fill_encap 2019-04-23 19:42:29 -07:00
mac80211.h mac80211: Use Airtime-based Queue Limits (AQL) on packet dequeue 2019-11-22 13:36:25 +01:00
mac802154.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
mip6.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
mld.h
mpls.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
mpls_iptunnel.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
mrp.h
ncsi.h
ndisc.h net: avoid potential false sharing in neighbor related code 2019-11-06 16:14:48 -08:00
neighbour.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-09 11:04:37 -08:00
net_failover.h
net_namespace.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-02 13:54:56 -07:00
net_ratelimit.h
netevent.h
netlabel.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
netlink.h netlink: Fix nlmsg_parse as a wrapper for strict message parsing 2019-08-13 20:37:16 -07:00
netprio_cgroup.h netprio: use css ID instead of cgroup ID 2019-11-12 08:18:03 -08:00
netrom.h net: netrom: Fix error cleanup path of nr_proto_init 2019-04-11 13:59:49 -07:00
nexthop.h net: Properly update v4 routes with v6 nexthop 2019-09-05 12:35:58 +02:00
nl802154.h
nsh.h
p8022.h
page_pool.h net: page_pool: add the possibility to sync DMA memory for device 2019-11-20 12:34:28 -08:00
ping.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
pkt_cls.h net: sched: take reference to action dev before calling offloads 2019-08-26 14:17:43 -07:00
pkt_sched.h Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2019-09-17 23:51:10 +02:00
pptp.h
protocol.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
psample.h net: sched: take reference to psample group in flow_action infra 2019-09-16 09:18:03 +02:00
psnap.h
raw.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
rawv6.h
red.h
regulatory.h
request_sock.h net: add {READ|WRITE}_ONCE() annotations on ->rskq_accept_head 2019-10-09 21:34:31 -07:00
rose.h
route.h ipv4: use dst hint for ipv4 list receive 2019-11-21 14:45:55 -08:00
rsi_91x.h
rtnetlink.h net: Add extack argument to rtnl_create_link 2018-11-06 15:00:45 -08:00
rtnh.h net: Rename net/nexthop.h net/rtnh.h 2019-04-22 21:47:25 -07:00
sch_generic.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-09 11:04:37 -08:00
scm.h
secure_seq.h
seg6.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
seg6_hmac.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
seg6_local.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
slhc_vj.h
smc.h net/smc: introduce bookkeeping of SMCD link groups 2019-11-15 12:28:28 -08:00
snmp.h net/tls: add skeleton of MIB statistics 2019-10-05 16:29:00 -07:00
sock.h Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-11-26 16:02:40 -08:00
sock_reuseport.h udp: correct reuseport selection with connected sockets 2019-09-16 09:02:18 +02:00
Space.h
stp.h
strparser.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
switchdev.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
tcp.h tcp: fix rejected syncookies due to stale timestamps 2019-12-06 21:05:14 -08:00
tcp_states.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
timewait_sock.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
tipc.h
tls.h net/tls: use sg_next() to walk sg entries 2019-11-28 22:40:29 -08:00
tls_toe.h net/tls: rename tls_hw_* functions tls_toe_* 2019-10-04 14:07:07 -07:00
transp_v6.h
tso.h
tun_proto.h
udp.h udp: Remove unlikely() from IS_ERR*() condition 2019-08-30 19:49:37 -07:00
udp_tunnel.h ipv6: Move ipv6 stubs to a separate header file 2019-03-29 10:53:45 -07:00
udplite.h
vsock_addr.h vsock: remove include/linux/vm_sockets.h file 2019-11-14 18:12:17 -08:00
vxlan.h vxlan: add adjacent link to limit depth level 2019-10-24 14:53:49 -07:00
wext.h
wimax.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 268 2019-06-05 17:30:29 +02:00
x25.h
x25device.h
xdp.h xdp: page_pool related fix to cpumap 2019-06-19 11:23:13 -04:00
xdp_priv.h page_pool: do not release pool until inflight == 0. 2019-11-16 12:39:10 -08:00
xdp_sock.h xsk: Restructure/inline XSKMAP lookup/redirect/flush 2019-11-02 00:38:49 +01:00
xfrm.h xfrm: ifdef setsockopt(UDP_ENCAP_ESPINUDP/UDP_ENCAP_ESPINUDP_NON_IKE) 2019-10-09 06:55:32 +02:00