linux/net/ipv4
Hannes Frederic Sowa f87c10a8aa ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu spoofing
While forwarding we should not use the protocol path mtu to calculate
the mtu for a forwarded packet but instead use the interface mtu.

We mark forwarded skbs in ip_forward with IPSKB_FORWARDED, which was
introduced for multicast forwarding. But as it does not conflict with
our usage in unicast code path it is perfect for reuse.

I moved the functions ip_sk_accept_pmtu, ip_sk_use_pmtu and ip_skb_dst_mtu
along with the new ip_dst_mtu_maybe_forward to net/ip.h to fix circular
dependencies because of IPSKB_FORWARDED.

Because someone might have written a software which does probe
destinations manually and expects the kernel to honour those path mtus
I introduced a new per-namespace "ip_forward_use_pmtu" knob so someone
can disable this new behaviour. We also still use mtus which are locked on a
route for forwarding.

The reason for this change is, that path mtus information can be injected
into the kernel via e.g. icmp_err protocol handler without verification
of local sockets. As such, this could cause the IPv4 forwarding path to
wrongfully emit fragmentation needed notifications or start to fragment
packets along a path.

Tunnel and ipsec output paths clear IPCB again, thus IPSKB_FORWARDED
won't be set and further fragmentation logic will use the path mtu to
determine the fragmentation size. They also recheck packet size with
help of path mtu discovery and report appropriate errors.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: John Heffner <johnwheffner@gmail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-13 11:22:54 -08:00
..
netfilter netfilter: nf_tables: fix error path in the init functions 2014-01-09 23:25:48 +01:00
Kconfig net: neighbour: Remove CONFIG_ARPD 2013-09-03 21:41:43 -04:00
Makefile gre_offload: statically build GRE offloading support 2014-01-06 20:28:34 -05:00
af_inet.c net-gre-gro: Add GRE support to the GRO stack 2014-01-07 16:21:31 -05:00
ah4.c ipv4: properly refresh rtable entries on pmtu/redirect events 2013-06-03 00:07:42 -07:00
arp.c ipv4: arp: update neighbour address when a gratuitous arp is received and arp_accept is set 2014-01-02 00:08:38 -05:00
cipso_ipv4.c ipv4: ERROR: code indent should use tabs where possible 2013-12-26 13:43:21 -05:00
datagram.c net: Remove FLOWI_FLAG_CAN_SLEEP 2013-12-06 07:24:39 +01:00
devinet.c ipv4: loopback device: ignore value changes after device is upped 2014-01-07 15:55:17 -05:00
esp4.c net: esp{4,6}: get rid of struct esp_data 2013-10-29 06:39:42 +01:00
fib_frontend.c fib_trie: remove duplicated rcu lock 2013-10-18 13:53:59 -04:00
fib_lookup.h ipv4: make fib_detect_death static 2013-12-28 17:01:46 -05:00
fib_rules.c inet: fix NULL pointer Oops in fib(6)_rule_suppress 2013-12-10 17:54:23 -05:00
fib_semantics.c ipv4: make fib_detect_death static 2013-12-28 17:01:46 -05:00
fib_trie.c seq_file: remove "%n" usage from seq_file users 2013-11-15 09:32:20 +09:00
gre_demux.c gre_offload: statically build GRE offloading support 2014-01-06 20:28:34 -05:00
gre_offload.c net-gre-gro: Add GRE support to the GRO stack 2014-01-07 16:21:31 -05:00
icmp.c ipv4: new ip_no_pmtu_disc mode to always discard incoming frag needed msgs 2013-12-18 16:58:20 -05:00
igmp.c ipv4: fix all space errors in file igmp.c 2013-12-26 13:43:21 -05:00
inet_connection_sock.c inet: rename ir_loc_port to ir_num 2013-10-10 14:37:35 -04:00
inet_diag.c net: inet_diag: zero out uninitialized idiag_{src,dst} fields 2013-12-19 14:55:52 -05:00
inet_fragment.c inet: remove old fragmentation hash initializing 2013-10-23 17:01:41 -04:00
inet_hashtables.c inet: convert inet_ehash_secret and ipv6_hash_secret to net_get_random_once 2013-10-19 19:45:35 -04:00
inet_lro.c lro: remove dead code 2013-12-29 16:34:25 -05:00
inet_timewait_sock.c tcp/dccp: remove twchain 2013-10-08 23:19:24 -04:00
inetpeer.c ipv4: remove unused function 2013-12-28 17:03:20 -05:00
ip_forward.c ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu spoofing 2014-01-13 11:22:54 -08:00
ip_fragment.c net: Add utility functions to clear rxhash 2013-12-17 16:36:21 -05:00
ip_gre.c ip_gre: fix msg_name parsing for recvfrom/recvmsg 2013-12-18 17:44:33 -05:00
ip_input.c net: add SNMP counters tracking incoming ECN bits 2013-08-08 22:24:59 -07:00
ip_options.c ipv4: switch and case should be at the same indent 2014-01-02 03:30:36 -05:00
ip_output.c ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu spoofing 2014-01-13 11:22:54 -08:00
ip_sockglue.c net: more spelling fixes 2013-12-10 21:57:11 -05:00
ip_tunnel.c ip_tunnel: fix sparse non static symbol warning 2014-01-09 14:31:47 -05:00
ip_tunnel_core.c net: Add utility functions to clear rxhash 2013-12-17 16:36:21 -05:00
ip_vti.c net: unify the pcpu_tstats and br_cpu_netstats as one 2014-01-04 20:10:24 -05:00
ipcomp.c ipv4: properly refresh rtable entries on pmtu/redirect events 2013-06-03 00:07:42 -07:00
ipconfig.c ipconfig: add informative timeout messages while waiting for carrier 2013-04-02 14:35:33 -04:00
ipip.c ipip: add GSO/TSO support 2013-10-19 19:36:19 -04:00
ipmr.c neigh: restore old behaviour of default parms values 2013-12-09 20:56:12 -05:00
netfilter.c netfilter: add my copyright statements 2013-04-18 20:27:55 +02:00
ping.c ipv4: ping make local stuff static 2013-12-28 17:05:45 -05:00
proc.c ipv4: spaces required around that '=' 2014-01-02 03:30:36 -05:00
protocol.c net: remove outdated comment for ipv4 and ipv6 protocol handler 2013-11-28 18:47:51 -05:00
raw.c net: Remove FLOWI_FLAG_CAN_SLEEP 2013-12-06 07:24:39 +01:00
route.c ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu spoofing 2014-01-13 11:22:54 -08:00
syncookies.c ipv4: fix checkpatch error "space prohibited" 2013-12-26 13:43:21 -05:00
sysctl_net_ipv4.c ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu spoofing 2014-01-13 11:22:54 -08:00
tcp.c tcp: out_of_order_queue do not use its lock 2014-01-06 16:34:34 -05:00
tcp_bic.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_cong.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_cubic.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_diag.c inet_diag: Rename inet_diag_req into inet_diag_req_v2 2012-01-11 12:56:06 -08:00
tcp_fastopen.c tcp: enable sockets to use MSG_FASTOPEN by default 2013-11-04 19:57:47 -05:00
tcp_highspeed.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_htcp.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_hybla.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_illinois.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_input.c tcp: make local functions static 2013-12-29 16:34:24 -05:00
tcp_ipv4.c ipv4: fix checkpatch error with foo * bar 2013-12-26 13:43:21 -05:00
tcp_lp.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_memcontrol.c tcp_memcontrol: Cleanup/fix cg_proto->memory_pressure handling. 2013-12-05 21:01:01 -05:00
tcp_metrics.c tcp: metrics: Allow selective get/del of tcp-metrics based on src IP 2014-01-10 17:38:18 -05:00
tcp_minisocks.c tcp: out_of_order_queue do not use its lock 2014-01-06 16:34:34 -05:00
tcp_offload.c net-gre-gro: Add GRE support to the GRO stack 2014-01-07 16:21:31 -05:00
tcp_output.c tcp: make local functions static 2013-12-29 16:34:24 -05:00
tcp_probe.c ipv4: ERROR: do not initialise globals to 0 or NULL 2013-12-26 13:43:21 -05:00
tcp_scalable.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_timer.c tcp: temporarily disable Fast Open on SYN timeout 2013-10-29 22:50:41 -04:00
tcp_vegas.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_vegas.h net: ipv4/ipv6: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
tcp_veno.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_westwood.c tcp: refactor F-RTO 2013-03-21 11:47:50 -04:00
tcp_yeah.c ipv4: ipv4: Cleanup the comments in tcp_yeah.c 2013-12-26 13:43:55 -05:00
tunnel4.c net: Convert printks to pr_<level> 2012-03-11 23:42:51 -07:00
udp.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-01-06 17:37:45 -05:00
udp_diag.c netlink: rename ssk to sk in struct netlink_skb_params 2013-04-19 14:57:56 -04:00
udp_impl.h net: ipv4/ipv6: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
udp_offload.c ipv4: fix tunneled VM traffic over hw VXLAN/GRE GSO NIC 2014-01-02 19:06:47 -05:00
udplite.c net: ipv4: Standardize prefixes for message logging 2012-03-12 17:05:21 -07:00
xfrm4_input.c net: Add skb_unclone() helper function. 2013-02-15 15:10:37 -05:00
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 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2013-09-30 15:24:57 -04:00
xfrm4_output.c xfrm: revert ipv4 mtu determination to dst_mtu 2013-08-26 12:40:53 +02:00
xfrm4_policy.c xfrm: Fix null pointer dereference when decoding sessions 2013-11-01 07:08:46 +01:00
xfrm4_state.c inet: make no_pmtu_disc per namespace and kill ipv4_config 2013-12-18 16:58:20 -05:00
xfrm4_tunnel.c sit: add IPv4 over IPv4 support 2013-05-31 17:19:05 -07:00