linux/net/ipv4
Eric Dumazet 75ff39ccc1 tcp: make challenge acks less predictable
Yue Cao claims that current host rate limiting of challenge ACKS
(RFC 5961) could leak enough information to allow a patient attacker
to hijack TCP sessions. He will soon provide details in an academic
paper.

This patch increases the default limit from 100 to 1000, and adds
some randomization so that the attacker can no longer hijack
sessions without spending a considerable amount of probes.

Based on initial analysis and patch from Linus.

Note that we also have per socket rate limiting, so it is tempting
to remove the host limit in the future.

v2: randomize the count of challenge acks per second, not the period.

Fixes: 282f23c6ee ("tcp: implement RFC 5961 3.2")
Reported-by: Yue Cao <ycao009@ucr.edu>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-11 13:33:35 -07:00
..
netfilter netfilter: conntrack: use a single expectation table for all namespaces 2016-05-06 11:50:01 +02:00
Kconfig ipv4: Remove inet_lro library 2016-02-17 16:15:46 -05:00
Makefile ipv4: Remove inet_lro library 2016-02-17 16:15:46 -05:00
af_inet.c ipv4: Fix non-initialized TTL when CONFIG_SYSCTL=n 2016-05-23 14:32:06 -07:00
ah4.c ah4: Fix error return in ah_input(). 2015-08-25 13:38:50 -07:00
arp.c net: rename NET_{ADD|INC}_STATS_BH() 2016-04-27 22:48:24 -04:00
cipso_ipv4.c net: introduce lockdep_is_held and update various places to use it 2016-04-07 16:44:14 -04:00
datagram.c net: Set sk_txhash from a random number 2015-07-29 22:44:04 -07:00
devinet.c ipv4: Don't do expensive useless work during inetdev destroy. 2016-03-13 23:28:35 -04:00
esp4.c esp: Fix ESN generation under UDP encapsulation 2016-06-23 11:52:00 -04:00
fib_frontend.c net: vrf: Create FIB tables on link create 2016-05-06 15:51:47 -04:00
fib_lookup.h ipv4: consider TOS in fib_select_default 2015-07-24 22:46:11 -07:00
fib_rules.c net: ipv6: use common fib_default_rule_pref 2015-09-09 14:19:50 -07:00
fib_semantics.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-05-15 13:32:48 -04:00
fib_trie.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-02-01 15:56:08 -08:00
fou.c fou: Support IPv6 in fou 2016-05-20 18:03:16 -04:00
gre_demux.c gre: fix error handler 2016-06-15 22:15:21 -07:00
gre_offload.c gso: Remove arbitrary checks for unsupported GSO 2016-05-20 18:03:15 -04:00
icmp.c net: icmp: rename ICMPMSGIN_INC_STATS_BH() 2016-04-27 22:48:23 -04:00
igmp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-03-08 12:34:12 -05:00
inet_connection_sock.c tcp: two more missing bh disable 2016-05-04 23:47:54 -04:00
inet_diag.c sock_diag: align nlattr properly when needed 2016-04-26 12:00:48 -04:00
inet_fragment.c inet: kill unused skb_free op 2016-01-05 22:25:57 -05:00
inet_hashtables.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-05-04 00:52:29 -04:00
inet_timewait_sock.c tcp: must block bh in __inet_twsk_hashdance() 2016-05-04 16:55:11 -04:00
inetpeer.c net: Add helper function to compare inetpeer addresses 2015-08-28 13:32:36 -07:00
ip_forward.c net: rename IP_ADD_STATS_BH() 2016-04-27 22:48:24 -04:00
ip_fragment.c net: rename IP_INC_STATS_BH() 2016-04-27 22:48:23 -04:00
ip_gre.c gre: fix error handler 2016-06-15 22:15:21 -07:00
ip_input.c net: original ingress device index in PKTINFO 2016-05-11 19:31:40 -04:00
ip_options.c net: ipv4: Convert IP network timestamps to be y2038 safe 2016-03-01 17:18:44 -05:00
ip_output.c ipv4: Fix ip_skb_dst_mtu to use the sk passed by ip_finish_output 2016-06-30 09:02:48 -04:00
ip_sockglue.c sock: propagate __sock_cmsg_send() error 2016-05-16 13:46:23 -04:00
ip_tunnel.c net: Cleanup encap items in ip_tunnels.h 2016-05-20 18:03:16 -04:00
ip_tunnel_core.c ip6_tun: Add infrastructure for doing encapsulation 2016-05-20 18:03:16 -04:00
ip_vti.c vti: Add pmtu handling to vti_xmit. 2016-03-31 08:59:56 +02:00
ipcomp.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
ipconfig.c ipconfig: Protect ic_addrservaddr with IPCONFIG_DYNAMIC. 2016-06-11 20:40:24 -07:00
ipip.c net: define gso types for IPx over IPv4 and IPv6 2016-05-20 18:03:15 -04:00
ipmr.c ipmr/ip6mr: Initialize the last assert time of mfc entries. 2016-06-28 04:14:09 -04:00
netfilter.c ipv4: Pass struct net into ip_route_me_harder 2015-09-29 20:21:32 +02:00
ping.c sock: enable timestamping using control messages 2016-04-04 15:50:30 -04:00
proc.c ipv4: Namespaceify ip_default_ttl sysctl knob 2016-02-16 20:42:54 -05:00
protocol.c net: Export inet_offloads and inet6_offloads 2014-09-19 17:15:31 -04:00
raw.c sock: enable timestamping using control messages 2016-04-04 15:50:30 -04:00
route.c net: l3mdev: Allow send on enslaved interface 2016-05-09 22:33:52 -04:00
syncookies.c net: rename NET_{ADD|INC}_STATS_BH() 2016-04-27 22:48:24 -04:00
sysctl_net_ipv4.c ipv4: Fix non-initialized TTL when CONFIG_SYSCTL=n 2016-05-23 14:32:06 -07:00
tcp.c tcp: guarantee forward progress in tcp_sendmsg() 2016-05-04 12:44:36 -04:00
tcp_bic.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_cdg.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_cong.c tcp: remove tcp_ecn_make_synack() socket argument 2015-09-25 13:00:38 -07:00
tcp_cubic.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_dctcp.c tcp: allow dctcp alpha to drop to zero 2015-10-23 02:46:52 -07:00
tcp_diag.c net: diag: Support destroying TCP sockets. 2015-12-15 23:26:52 -05:00
tcp_fastopen.c tcp: do not assume TCP code is non preemptible 2016-05-02 17:02:25 -04:00
tcp_highspeed.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_htcp.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_hybla.c tcp: do not slow start when cwnd equals ssthresh 2015-07-09 14:22:52 -07:00
tcp_illinois.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_input.c tcp: make challenge acks less predictable 2016-07-11 13:33:35 -07:00
tcp_ipv4.c tcp: minor optimizations around tcp_hdr() usage 2016-05-16 13:46:23 -04:00
tcp_lp.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_metrics.c libnl: nla_put_msecs(): align on a 64-bit area 2016-04-23 20:13:24 -04:00
tcp_minisocks.c tcp: do not assume TCP code is non preemptible 2016-05-02 17:02:25 -04:00
tcp_offload.c gso: Remove arbitrary checks for unsupported GSO 2016-05-20 18:03:15 -04:00
tcp_output.c tcp: do not send too big packets at retransmit time 2016-06-29 05:25:11 -04:00
tcp_probe.c net: ipv4: tcp_probe: Replace timespec with timespec64 2016-03-01 17:18:44 -05:00
tcp_recovery.c tcp: do not assume TCP code is non preemptible 2016-05-02 17:02:25 -04:00
tcp_scalable.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_timer.c tcp: do not assume TCP code is non preemptible 2016-05-02 17:02:25 -04:00
tcp_vegas.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_vegas.h tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_veno.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_westwood.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_yeah.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tunnel4.c
udp.c udp: prevent bugcheck if filter truncates packet too much 2016-07-11 12:43:15 -07:00
udp_diag.c udp: no longer use SLAB_DESTROY_BY_RCU 2016-04-04 22:11:19 -04:00
udp_impl.h net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
udp_offload.c gso: Remove arbitrary checks for unsupported GSO 2016-05-20 18:03:15 -04:00
udp_tunnel.c udp: Add socket based GRO and config 2016-04-07 16:53:29 -04:00
udplite.c net: Eliminate no_check from protosw 2014-05-23 16:28:53 -04:00
xfrm4_input.c netfilter: Pass net into okfn 2015-09-17 17:18:37 -07:00
xfrm4_mode_beet.c ipv4: ERROR: code indent should use tabs where possible 2013-12-26 13:43:21 -05:00
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c ipv4: hash net ptr into fragmentation bucket selection 2015-03-25 14:07:04 -04:00
xfrm4_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-10-24 06:54:12 -07:00
xfrm4_policy.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec 2015-12-22 16:26:31 -05:00
xfrm4_protocol.c xfrm4: Remove duplicate semicolon 2014-06-30 07:49:47 +02:00
xfrm4_state.c
xfrm4_tunnel.c