android_kernel_motorola_sm6225/net/ipv4
Hannes Frederic Sowa 482fc6094a ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE
Sockets marked with IP_PMTUDISC_INTERFACE won't do path mtu discovery,
their sockets won't accept and install new path mtu information and they
will always use the interface mtu for outgoing packets. It is guaranteed
that the packet is not fragmented locally. But we won't set the DF-Flag
on the outgoing frames.

Florian Weimer had the idea to use this flag to ensure DNS servers are
never generating outgoing fragments. They may well be fragmented on the
path, but the server never stores or usees path mtu values, which could
well be forged in an attack.

(The root of the problem with path MTU discovery is that there is
no reliable way to authenticate ICMP Fragmentation Needed But DF Set
messages because they are sent from intermediate routers with their
source addresses, and the IMCP payload will not always contain sufficient
information to identify a flow.)

Recent research in the DNS community showed that it is possible to
implement an attack where DNS cache poisoning is feasible by spoofing
fragments. This work was done by Amir Herzberg and Haya Shulman:
<https://sites.google.com/site/hayashulman/files/fragmentation-poisoning.pdf>

This issue was previously discussed among the DNS community, e.g.
<http://www.ietf.org/mail-archive/web/dnsext/current/msg01204.html>,
without leading to fixes.

This patch depends on the patch "ipv4: fix DO and PROBE pmtu mode
regarding local fragmentation with UFO/CORK" for the enforcement of the
non-fragmentable checks. If other users than ip_append_page/data should
use this semantic too, we have to add a new flag to IPCB(skb)->flags to
suppress local fragmentation and check for this in ip_finish_output.

Many thanks to Florian Weimer for the idea and feedback while implementing
this patch.

Cc: David S. Miller <davem@davemloft.net>
Suggested-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-05 21:52:27 -05:00
..
netfilter Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nftables 2013-11-04 19:48:57 -05:00
af_inet.c inet: restore gso for vxlan 2013-10-28 00:23:06 -04:00
ah4.c ipv4: properly refresh rtable entries on pmtu/redirect events 2013-06-03 00:07:42 -07:00
arp.c net: neighbour: Remove CONFIG_ARPD 2013-09-03 21:41:43 -04:00
cipso_ipv4.c cipso: don't follow a NULL pointer when setsockopt() is called 2012-07-18 09:01:12 -07:00
datagram.c ipv4: Add a socket release callback for datagram sockets 2013-01-21 14:17:05 -05:00
devinet.c net: igmp: Allow user-space configuration of igmp unsolicited report interval 2013-08-09 11:27:46 -07:00
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 net: ipv4/ipv6: Remove extern from function prototypes 2013-10-19 19:12:11 -04:00
fib_rules.c fib_rules: fix suppressor names and default values 2013-08-03 10:40:23 -07:00
fib_semantics.c fib: Use const struct nl_info * in rtmsg_fib 2013-10-18 14:42:15 -04:00
fib_trie.c fib_trie: only calc for the un-first node 2013-10-10 00:08:07 -04:00
gre_demux.c ipv4: generalize gre_handle_offloads 2013-10-19 19:36:18 -04:00
gre_offload.c ipip: add GSO/TSO support 2013-10-19 19:36:19 -04:00
icmp.c ipv4: processing ancillary IP_TOS or IP_TTL 2013-09-28 15:21:52 -07:00
igmp.c ipv4 igmp: use in_dev_put in timer handlers instead of __in_dev_put 2013-09-30 22:28:56 -07:00
inet_connection_sock.c inet: rename ir_loc_port to ir_num 2013-10-10 14:37:35 -04:00
inet_diag.c inet_diag: use sock_gen_put() 2013-10-17 15:02:02 -04:00
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 ipv4: replace ip_fast_csum with csum_replace2 2013-03-15 09:12:25 -04:00
inet_timewait_sock.c tcp/dccp: remove twchain 2013-10-08 23:19:24 -04:00
inetpeer.c ip: generate unique IP identificator if local fragmentation is allowed 2013-09-19 14:11:15 -04:00
ip_forward.c ipv4: introduce rt_uses_gateway 2012-10-08 17:42:36 -04:00
ip_fragment.c ipv4: initialize ip4_frags hash secret as late as possible 2013-10-23 17:01:40 -04:00
ip_gre.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-08-16 15:37:26 -07:00
ip_input.c net: add SNMP counters tracking incoming ECN bits 2013-08-08 22:24:59 -07:00
ip_options.c net/ipv4: Ensure that location of timestamp option is stored 2013-03-12 05:35:39 -04:00
ip_output.c ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE 2013-11-05 21:52:27 -05:00
ip_sockglue.c ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE 2013-11-05 21:52:27 -05:00
ip_tunnel.c ip_tunnel: Remove double unregister of the fallback device 2013-10-01 12:42:16 -04:00
ip_tunnel_core.c ipv4: generalize gre_handle_offloads 2013-10-19 19:36:18 -04:00
ip_vti.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-10-23 16:49:34 -04:00
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 ip: generate unique IP identificator if local fragmentation is allowed 2013-09-19 14:11:15 -04:00
Kconfig net: neighbour: Remove CONFIG_ARPD 2013-09-03 21:41:43 -04:00
Makefile net: gre: move GSO functions to gre_offload 2013-07-03 14:37:39 -07:00
netfilter.c netfilter: add my copyright statements 2013-04-18 20:27:55 +02:00
ping.c net: fix build errors if ipv6 is disabled 2013-10-09 13:04:03 -04:00
proc.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-08-16 15:37:26 -07:00
protocol.c ipv4: Disallow non-namespace aware protocols to register. 2013-02-05 14:42:23 -05:00
raw.c net: ipv4 only populate IP_PKTINFO when needed 2013-10-08 16:27:33 -04:00
route.c ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE 2013-11-05 21:52:27 -05:00
syncookies.c inet: split syncookie keys for ipv4 and ipv6 and initialize with net_get_random_once 2013-10-19 19:45:35 -04:00
sysctl_net_ipv4.c tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp.c tcp_memcontrol: Remove the per netns control. 2013-10-21 18:43:02 -04:00
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: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tcp_ipv4.c ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE 2013-11-05 21:52:27 -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: Kill struct tcp_memcontrol 2013-10-21 18:43:02 -04:00
tcp_metrics.c tcp: temporarily disable Fast Open on SYN timeout 2013-10-29 22:50:41 -04:00
tcp_minisocks.c ipv6: make lookups simpler and faster 2013-10-09 00:01:25 -04:00
tcp_offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-11-04 13:48:30 -05:00
tcp_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-10-23 16:49:34 -04:00
tcp_probe.c ipv6: make lookups simpler and faster 2013-10-09 00:01:25 -04:00
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 tcp: properly handle stretch acks in slow start 2013-11-04 19:57:59 -05:00
tunnel4.c net: Convert printks to pr_<level> 2012-03-11 23:42:51 -07:00
udp.c inet: convert inet_ehash_secret and ipv6_hash_secret to net_get_random_once 2013-10-19 19:45:35 -04:00
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 ipip: add GSO/TSO support 2013-10-19 19:36:19 -04:00
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 ipsec: be careful of non existing mac headers 2012-02-23 16:50:45 -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 xfrm: make local error reporting more robust 2013-08-14 13:07:12 +02:00
xfrm4_tunnel.c sit: add IPv4 over IPv4 support 2013-05-31 17:19:05 -07:00