linux/net/ipv4
Eric Dumazet 190cc82489 tcp: change source port randomizarion at connect() time
RFC 6056 (Recommendations for Transport-Protocol Port Randomization)
provides good summary of why source selection needs extra care.

David Dworken reminded us that linux implements Algorithm 3
as described in RFC 6056 3.3.3

Quoting David :
   In the context of the web, this creates an interesting info leak where
   websites can count how many TCP connections a user's computer is
   establishing over time. For example, this allows a website to count
   exactly how many subresources a third party website loaded.
   This also allows:
   - Distinguishing between different users behind a VPN based on
       distinct source port ranges.
   - Tracking users over time across multiple networks.
   - Covert communication channels between different browsers/browser
       profiles running on the same computer
   - Tracking what applications are running on a computer based on
       the pattern of how fast source ports are getting incremented.

Section 3.3.4 describes an enhancement, that reduces
attackers ability to use the basic information currently
stored into the shared 'u32 hint'.

This change also decreases collision rate when
multiple applications need to connect() to
different destinations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: David Dworken <ddworken@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-02-11 13:13:04 -08:00
..
bpfilter net: Revert "net: optimize the sockptr_t for unified kernel/user address spaces" 2020-08-10 12:06:44 -07:00
netfilter netfilter: nftables: add nft_parse_register_load() and use it 2021-01-27 22:53:29 +01:00
af_inet.c inet: do not export inet_gro_{receive|complete} 2021-02-02 18:41:10 -08:00
ah4.c inet: Use fallthrough; 2020-03-12 15:55:00 -07:00
arp.c net: Exempt multicast addresses from five-second neighbor lifetime 2020-11-13 14:24:39 -08:00
bpf_tcp_ca.c bpf: Remove hard-coded btf_vmlinux assumption from BPF verifier 2020-12-03 17:38:21 -08:00
cipso_ipv4.c cipso: fix 'audit_secid' kernel-doc warning in cipso_ipv4.c 2020-09-08 20:03:36 -07:00
datagram.c
devinet.c treewide: rename nla_strlcpy to nla_strscpy. 2020-11-16 08:08:54 -08:00
esp4_offload.c net: Simplify the calculation of variables 2021-01-27 11:49:55 +01:00
esp4.c esp: avoid unneeded kmap_atomic call 2021-01-11 18:20:09 -08:00
fib_frontend.c ipv4: Ignore ECN bits for fib lookups in fib_compute_spec_dst() 2020-12-28 14:44:32 -08:00
fib_lookup.h IPv4: Add "offload failed" indication to routes 2021-02-08 16:47:03 -08:00
fib_notifier.c
fib_rules.c fib: use indirect call wrappers in the most common fib_rules_ops 2020-07-28 17:42:31 -07:00
fib_semantics.c IPv4: Add "offload failed" indication to routes 2021-02-08 16:47:03 -08:00
fib_trie.c IPv4: Extend 'fib_notify_on_flag_change' sysctl 2021-02-08 16:47:03 -08:00
fou.c genetlink: move to smaller ops wherever possible 2020-10-02 19:11:11 -07:00
gre_demux.c erspan: fix version 1 check in gre_parse_header() 2020-12-28 15:00:00 -08:00
gre_offload.c ip_gre: add csum offload support for gre header 2021-01-29 20:39:14 -08:00
icmp.c lsm,selinux: pass flowi_common instead of flowi to the LSM hooks 2020-11-23 18:36:21 -05:00
igmp.c ip*_mc_gsfget(): lift copyout of struct group_filter into callers 2020-05-20 20:31:27 -04:00
inet_connection_sock.c tcp: fix TCP_USER_TIMEOUT with zero window 2021-01-18 19:59:17 -08:00
inet_diag.c inet_diag: Fix error path to cancel the meseage in inet_req_diag_fill() 2020-11-17 16:08:36 -08:00
inet_fragment.c inet: frags: batch fqdir destroy works 2020-12-12 15:08:54 -08:00
inet_hashtables.c tcp: change source port randomizarion at connect() time 2021-02-11 13:13:04 -08:00
inet_timewait_sock.c net: Use generic ns_common::count 2020-08-19 14:06:36 +02:00
inetpeer.c
ip_forward.c
ip_fragment.c
ip_gre.c ipv4/ipv6: switch to dev_get_tstats64 2020-11-09 17:50:28 -08:00
ip_input.c net: use indirect call helpers for dst_input 2021-02-03 14:51:39 -08:00
ip_options.c net: clean up codestyle for net/ipv4 2020-08-25 06:28:02 -07:00
ip_output.c net: use indirect call helpers for dst_output 2021-02-03 14:51:39 -08:00
ip_sockglue.c net: Remove duplicated midx check against 0 2020-08-25 06:23:59 -07:00
ip_tunnel_core.c net: ip_tunnel: clean up endianness conversions 2021-01-08 19:25:35 -08:00
ip_tunnel.c net: ip_tunnel: fix mtu calculation 2021-02-01 19:58:23 -08:00
ip_vti.c vti: switch to dev_get_tstats64 2020-11-09 17:50:28 -08:00
ipcomp.c ipcomp: assign if_id to child tunnel from parent tunnel 2020-07-09 12:55:37 +02:00
ipconfig.c Revert "net: ipv4: handle DSA enabled master network devices" 2021-02-06 14:42:57 -08:00
ipip.c ipv4/ipv6: switch to dev_get_tstats64 2020-11-09 17:50:28 -08:00
ipmr_base.c
ipmr.c ipmr: Use full VIF ID in netlink cache reports 2020-09-10 12:25:51 -07:00
Kconfig net: ipv4: remove duplicate "the the" phrase in Kconfig text 2020-08-18 16:02:16 -07:00
Makefile udp_tunnel: add central NIC RX port offload infrastructure 2020-07-10 13:54:00 -07:00
metrics.c treewide: rename nla_strlcpy to nla_strscpy. 2020-11-16 08:08:54 -08:00
netfilter.c netfilter: use actual socket sk rather than skb sk when routing harder 2020-10-30 12:57:39 +01:00
netlink.c
nexthop.c nexthop: Extract a helper for validation of get/del RTNL requests 2021-01-28 20:49:54 -08:00
ping.c lsm,selinux: pass flowi_common instead of flowi to the LSM hooks 2020-11-23 18:36:21 -05:00
proc.c net: proc: speedup /proc/net/netstat 2021-01-29 20:59:53 -08:00
protocol.c
raw_diag.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-03-12 22:34:48 -07:00
raw.c lsm,selinux: pass flowi_common instead of flowi to the LSM hooks 2020-11-23 18:36:21 -05:00
route.c IPv4: Add "offload failed" indication to routes 2021-02-08 16:47:03 -08:00
syncookies.c selinux/stable-5.11 PR 20201214 2020-12-16 11:01:04 -08:00
sysctl_net_ipv4.c IPv4: Extend 'fib_notify_on_flag_change' sysctl 2021-02-08 16:47:03 -08:00
tcp_bbr.c tcp: only postpone PROBE_RTT if RTT is < current min_rtt estimate 2020-11-17 11:03:22 -08:00
tcp_bic.c tcp: fix stretch ACK bugs in BIC 2020-03-16 18:26:54 -07:00
tcp_bpf.c bpf, sockmap: Ensure SO_RCVBUF memory is observed on ingress redirect 2020-11-18 00:12:34 +01:00
tcp_cdg.c
tcp_cong.c tcp: Set INET_ECN_xmit configuration in tcp_reinit_congestion_control 2020-11-20 18:09:47 -08:00
tcp_cubic.c tcp_cubic: use memset and offsetof init 2021-01-15 20:22:16 -08:00
tcp_dctcp.c
tcp_dctcp.h
tcp_diag.c inet_diag: Move the INET_DIAG_REQ_BYTECODE nlattr to cb->data 2020-02-27 18:50:19 -08:00
tcp_fastopen.c bpf: tcp: Add bpf_skops_established() 2020-08-24 14:35:00 -07:00
tcp_highspeed.c Replace HTTP links with HTTPS ones: IPv* 2020-07-06 13:23:03 -07:00
tcp_htcp.c Replace HTTP links with HTTPS ones: IPv* 2020-07-06 13:23:03 -07:00
tcp_hybla.c
tcp_illinois.c
tcp_input.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-01-28 17:09:31 -08:00
tcp_ipv4.c net: indirect call helpers for ipv4/ipv6 dst_check functions 2021-02-03 14:51:40 -08:00
tcp_lp.c net: ipv4: Fix some kerneldoc warnings in TCP Low Priority 2020-10-30 12:10:57 -07:00
tcp_metrics.c fixes-v5.11 2020-12-14 16:40:27 -08:00
tcp_minisocks.c tcp: parse mptcp options contained in reset packets 2020-12-14 17:30:06 -08:00
tcp_nv.c
tcp_offload.c
tcp_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-01-28 17:09:31 -08:00
tcp_rate.c
tcp_recovery.c tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN 2021-01-23 21:33:01 -08:00
tcp_scalable.c net: ipv4: delete repeated words 2020-08-24 17:31:20 -07:00
tcp_timer.c tcp: make TCP_USER_TIMEOUT accurate for zero window probes 2021-01-23 19:32:51 -08:00
tcp_ulp.c bpf: sockmap: Only check ULP for TCP sockets 2020-03-09 22:34:58 +01:00
tcp_vegas.c tcp: use semicolons rather than commas to separate statements 2020-10-13 17:11:52 -07:00
tcp_vegas.h
tcp_veno.c Replace HTTP links with HTTPS ones: IPv* 2020-07-06 13:23:03 -07:00
tcp_westwood.c
tcp_yeah.c tcp: fix stretch ACK bugs in Yeah 2020-03-16 18:26:55 -07:00
tcp.c tcp: Add receive timestamp support for receive zerocopy. 2021-01-22 20:05:56 -08:00
tunnel4.c tunnel4: add cb_handler to struct xfrm_tunnel 2020-07-09 12:51:36 +02:00
udp_bpf.c net: sk_msg: Simplify sk_psock initialization 2020-08-21 15:16:11 -07:00
udp_diag.c net: udp: remove redundant initialization in udp_dump_one 2020-11-09 16:42:49 -08:00
udp_impl.h net: pass a sockptr_t into ->setsockopt 2020-07-24 15:41:54 -07:00
udp_offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-02-02 14:21:31 -08:00
udp_tunnel_core.c udp_tunnel: reshuffle NETIF_F_RX_UDP_TUNNEL_PORT checks 2021-01-07 12:53:29 -08:00
udp_tunnel_nic.c udp_tunnel: add the ability to share port tables 2020-09-28 12:50:12 -07:00
udp_tunnel_stub.c udp_tunnel: add central NIC RX port offload infrastructure 2020-07-10 13:54:00 -07:00
udp.c udp: call udp_encap_enable for v6 sockets when enabling encap 2021-02-04 18:37:14 -08:00
udplite.c net/ipv4: remove compat_ip_{get,set}sockopt 2020-07-19 18:16:41 -07:00
xfrm4_input.c xfrm: state: remove extract_input indirection from xfrm_state_afinfo 2020-05-06 09:40:08 +02:00
xfrm4_output.c xfrm: fix unused variable warning if CONFIG_NETFILTER=n 2020-05-11 15:12:27 +02:00
xfrm4_policy.c net: add bool confirm_neigh parameter for dst_ops.update_pmtu 2019-12-24 22:28:54 -08:00
xfrm4_protocol.c xfrm: add route lookup to xfrm4_rcv_encap 2019-12-09 09:59:07 +01:00
xfrm4_state.c xfrm: remove output_finish indirection from xfrm_state_afinfo 2020-05-06 09:40:08 +02:00
xfrm4_tunnel.c xfrm: interface: fix the priorities for ipip and ipv6 tunnels 2020-10-09 12:29:48 +02:00