linux/include/net
Marcelo Ricardo Leitner b6c5734db0 sctp: fix the handling of ICMP Frag Needed for too small MTUs
syzbot reported a hang involving SCTP, on which it kept flooding dmesg
with the message:
[  246.742374] sctp: sctp_transport_update_pmtu: Reported pmtu 508 too
low, using default minimum of 512

That happened because whenever SCTP hits an ICMP Frag Needed, it tries
to adjust to the new MTU and triggers an immediate retransmission. But
it didn't consider the fact that MTUs smaller than the SCTP minimum MTU
allowed (512) would not cause the PMTU to change, and issued the
retransmission anyway (thus leading to another ICMP Frag Needed, and so
on).

As IPv4 (ip_rt_min_pmtu=556) and IPv6 (IPV6_MIN_MTU=1280) minimum MTU
are higher than that, sctp_transport_update_pmtu() is changed to
re-fetch the PMTU that got set after our request, and with that, detect
if there was an actual change or not.

The fix, thus, skips the immediate retransmission if the received ICMP
resulted in no change, in the hope that SCTP will select another path.

Note: The value being used for the minimum MTU (512,
SCTP_DEFAULT_MINSEGMENT) is not right and instead it should be (576,
SCTP_MIN_PMTU), but such change belongs to another patch.

Changes from v1:
- do not disable PMTU discovery, in the light of commit
06ad391919 ("[SCTP] Don't disable PMTU discovery when mtu is small")
and as suggested by Xin Long.
- changed the way to break the rtx loop by detecting if the icmp
  resulted in a change or not
Changes from v2:
none

See-also: https://lkml.org/lkml/2017/12/22/811
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-08 14:19:13 -05:00
..
9p 9p: Implement show_options 2017-07-11 06:08:58 -04:00
bluetooth Bluetooth: Use bt_dev_err and bt_dev_info when possible 2017-10-30 12:25:45 +02:00
caif
iucv License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
netfilter Modules updates for v4.15 2017-11-15 13:46:33 -08:00
netns tcp: Namespace-ify sysctl_tcp_default_congestion_control 2017-11-15 14:09:52 +09:00
nfc NFC: Add nfc_dbg() macro 2017-04-05 10:15:20 +02:00
phonet net: phonet: mark phonet_protocol as const 2017-10-07 23:15:08 +01:00
sctp sctp: fix the handling of ICMP Frag Needed for too small MTUs 2018-01-08 14:19:13 -05:00
tc_act act_sample: get rid of tcf_sample_cleanup_rcu() 2017-11-30 10:19:17 -05:00
6lowpan.h 6lowpan: Fix IID format for Bluetooth 2017-04-12 22:02:36 +02:00
act_api.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-10 10:00:18 +09:00
addrconf.h ipv6: remove IN6_ADDR_HSIZE from addrconf.h 2017-11-05 09:17:27 +09:00
af_ieee802154.h
af_rxrpc.h rxrpc: Provide functions for allowing cleaner handling of signals 2017-10-18 11:42:48 +01:00
af_unix.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
af_vsock.h VSOCK: use TCP state constants for sk_state 2017-10-05 18:44:17 -07:00
ah.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
arp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
atmclip.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ax25.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ax88796.h
bond_3ad.h
bond_alb.h
bond_options.h bonding: Prevent duplicate userspace notification 2017-05-27 18:51:41 -04:00
bonding.h bonding: remove rtmsg_ifinfo called after bond_lower_state_changed 2017-10-25 10:54:39 +09:00
busy_poll.h net: fix compilation when busy poll is not enabled 2017-08-11 14:59:24 -07:00
calipso.h net, calipso: convert calipso_doi.refcount from atomic_t to refcount_t 2017-07-04 22:35:16 +01:00
cfg80211-wext.h
cfg80211.h nl80211: Remove obsolete kerneldoc line 2017-12-19 09:15:36 +01:00
cfg802154.h
checksum.h csum: eliminate sparse warning in remcsum_unadjust() 2017-01-20 12:12:13 -05:00
cipso_ipv4.h net, ipv4: convert cipso_v4_doi.refcount from atomic_t to refcount_t 2017-07-04 01:29:04 -07:00
cls_cgroup.h
codel_impl.h
codel_qdisc.h
codel.h
compat.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
datalink.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dcbevent.h
dcbnl.h
devlink.h devlink: Add IPv6 header for dpipe 2017-08-31 14:42:19 -07:00
dn_dev.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dn_fib.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dn_neigh.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dn_nsp.h net/decnet: Convert timers to use timer_setup() 2017-10-18 12:39:36 +01:00
dn_route.h
dn.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
dsa.h net: dsa: Support prepended Broadcom tag 2017-11-13 10:34:54 +09:00
dsfield.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dst_cache.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dst_metadata.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
dst_ops.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dst.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
erspan.h gre: introduce native tunnel support for ERSPAN 2017-08-22 14:29:30 -07:00
esp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ethoc.h
fib_notifier.h net: Add extack to fib_notifier_info 2017-11-01 11:50:43 +09:00
fib_rules.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
firewire.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
flow_dissector.h tipc: improve link resiliency when rps is activated 2017-11-11 15:36:05 +09:00
flow.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fou.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fq_impl.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-30 21:09:24 +09:00
fq.h fq: support filtering a given tin 2017-10-11 09:49:34 +02:00
garp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gen_stats.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
genetlink.h genetlink: fix genlmsg_nlhdr() 2017-11-16 10:49:00 +09:00
geneve.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gre.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gro_cells.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gtp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gue.h fou: fix some member types in guehdr 2017-12-11 14:10:06 -05:00
hwbm.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
icmp.h
ieee80211_radiotap.h wireless: radiotap: rewrite the radiotap header file 2017-01-25 16:00:33 +01:00
ieee802154_netdev.h
if_inet6.h net, ipv6: convert ifacaddr6.aca_refcnt from atomic_t to refcount_t 2017-07-04 01:29:04 -07:00
ife.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ila.h
inet6_connection_sock.h inet: drop ->bind_conflict 2017-01-18 13:04:28 -05:00
inet6_hashtables.h net: ipv6: add second dif to inet6 socket lookups 2017-08-07 11:39:22 -07:00
inet_common.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
inet_connection_sock.h inet/connection_sock: Convert timers to use timer_setup() 2017-10-18 12:39:55 +01:00
inet_ecn.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
inet_frag.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
inet_hashtables.h net: ipv4: add second dif to inet socket lookups 2017-08-07 11:39:21 -07:00
inet_sock.h Merge branch 'akpm' (patches from Andrew) 2017-11-15 19:42:40 -08:00
inet_timewait_sock.h kmemcheck: remove annotations 2017-11-15 18:21:04 -08:00
inetpeer.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ip6_checksum.h
ip6_fib.h ipv6: take care of rt6_stats 2017-10-07 21:22:58 +01:00
ip6_route.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
ip6_tunnel.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ip_fib.h net: ipv4: remove fib_weight 2017-09-29 06:19:32 +01:00
ip_tunnels.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
ip_vs.h Merge branch 'linus' into locking/core, to resolve conflicts 2017-11-07 10:32:44 +01:00
ip.h ipv4: igmp: guard against silly MTU values 2017-12-13 13:13:58 -05:00
ipcomp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ipconfig.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ipv6.h net: accept UFO datagrams from tuntap and packet 2017-11-24 01:37:35 +09:00
ipx.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iw_handler.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kcm.h
l3mdev.h
lapb.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
lib80211.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
llc_c_ac.h net: LLC: Convert timers to use timer_setup() 2017-10-25 12:06:25 +09:00
llc_c_ev.h
llc_c_st.h
llc_conn.h
llc_if.h
llc_pdu.h
llc_s_ac.h
llc_s_ev.h
llc_s_st.h
llc_sap.h
llc.h net, llc: convert llc_sap.refcnt from atomic_t to refcount_t 2017-07-04 22:35:15 +01:00
lwtunnel.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mac80211.h mac80211: use QoS NDP for AP probing 2017-11-27 11:23:20 +01:00
mac802154.h
mip6.h
mld.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mpls_iptunnel.h net: mpls: Increase max number of labels for lwt encap 2017-04-01 20:21:44 -07:00
mpls.h
mrp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ncsi.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ndisc.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
neighbour.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
net_namespace.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
net_ratelimit.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
netevent.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
netlabel.h net: convert netlbl_lsm_cache.refcount from atomic_t to refcount_t 2017-07-01 07:39:09 -07:00
netlink.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
netprio_cgroup.h
netrom.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nexthop.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nl802154.h
nsh.h openvswitch: enable NSH support 2017-11-08 16:12:33 +09:00
p8022.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ping.h
pkt_cls.h cls_bpf: fix offload assumptions after callback conversion 2017-12-20 13:08:18 -05:00
pkt_sched.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
pptp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
protocol.h IPv4: early demux can return an error code 2017-10-01 03:55:47 +01:00
psample.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
psnap.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
raw.h net: ipv4: add second dif to raw socket lookups 2017-08-07 11:39:21 -07:00
rawv6.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
red.h net_sched: red: Avoid illegal values 2017-12-05 14:37:13 -05:00
regulatory.h
request_sock.h tcp: socket option to set TCP fast open key 2017-10-20 13:21:36 +01:00
rose.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
route.h udp: perform source validation for mcast early demux 2017-10-01 03:55:47 +01:00
rtnetlink.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
sch_generic.h net: sched: Add TCA_HW_OFFLOAD 2017-12-15 13:35:36 -05:00
scm.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
secure_seq.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
seg6_hmac.h ipv6: sr: add core files for SR HMAC support 2016-11-09 20:40:06 -05:00
seg6.h ipv6: sr: add support for ip4ip6 encapsulation 2017-08-25 17:10:23 -07:00
slhc_vj.h
smc.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
snmp.h
sock_reuseport.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sock.h sock: Add sock_owned_by_user_nocheck 2017-12-28 14:28:22 -05:00
Space.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
stp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
strparser.h strparser: Use delayed work instead of timer for msg timeout 2017-10-25 10:37:11 +09:00
switchdev.h net: bridge: Add/del switchdev object on host join/leave 2017-11-10 13:41:40 +09:00
tcp_states.h
tcp.h tcp: invalidate rate samples during SACK reneging 2017-12-08 10:07:02 -05:00
timewait_sock.h
tipc.h tipc: improve link resiliency when rps is activated 2017-11-11 15:36:05 +09:00
tls.h uapi: fix linux/tls.h userspace compilation error 2017-11-15 13:54:18 +09:00
transp_v6.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tso.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tun_proto.h vxlan: factor out VXLAN-GPE next protocol 2017-08-29 15:16:52 -07:00
udp_tunnel.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
udp.h IPv4: early demux can return an error code 2017-10-01 03:55:47 +01:00
udplite.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vsock_addr.h
vxlan.h vxlan: trivial indenting fix. 2018-01-03 11:33:37 -05:00
wext.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
wimax.h
x25.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
x25device.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfrm.h xfrm: Reinject transport-mode packets through tasklet 2017-12-19 08:23:21 +01:00