linux/include/net
Jakub Sitnicki f1ff5ce2cd net, sk_msg: Clear sk_user_data pointer on clone if tagged
sk_user_data can hold a pointer to an object that is not intended to be
shared between the parent socket and the child that gets a pointer copy on
clone. This is the case when sk_user_data points at reference-counted
object, like struct sk_psock.

One way to resolve it is to tag the pointer with a no-copy flag by
repurposing its lowest bit. Based on the bit-flag value we clear the child
sk_user_data pointer after cloning the parent socket.

The no-copy flag is stored in the pointer itself as opposed to externally,
say in socket flags, to guarantee that the pointer and the flag are copied
from parent to child socket in an atomic fashion. Parent socket state is
subject to change while copying, we don't hold any locks at that time.

This approach relies on an assumption that sk_user_data holds a pointer to
an object aligned at least 2 bytes. A manual audit of existing users of
rcu_dereference_sk_user_data helper confirms our assumption.

Also, an RCU-protected sk_user_data is not likely to hold a pointer to a
char value or a pathological case of "struct { char c; }". To be safe, warn
when the flag-bit is set when setting sk_user_data to catch any future
misuses.

It is worth considering why clearing sk_user_data unconditionally is not an
option. There exist users, DRBD, NVMe, and Xen drivers being among them,
that rely on the pointer being copied when cloning the listening socket.

Potentially we could distinguish these users by checking if the listening
socket has been created in kernel-space via sock_create_kern, and hence has
sk_kern_sock flag set. However, this is not the case for NVMe and Xen
drivers, which create sockets without marking them as belonging to the
kernel.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200218171023.844439-3-jakub@cloudflare.com
2020-02-21 22:29:45 +01:00
..
9p treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188 2019-05-30 11:29:21 -07:00
bluetooth Bluetooth: monitor: Add support for ISO packets 2020-01-15 22:28:51 +01:00
caif treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 194 2019-05-30 11:29:22 -07:00
iucv net/af_iucv: locate IUCV header via skb_network_header() 2018-09-26 09:56:07 -07:00
netfilter nf_tables: Add set type for arbitrary concatenation of ranges 2020-01-27 08:54:30 +01:00
netns Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-26 10:40:21 +01:00
nfc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
phonet treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 336 2019-06-05 17:37:07 +02:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-25 14:57:26 -08:00
tc_act net: sched: refactor ct action helpers to require tcf_lock 2020-02-17 14:17:02 -08:00
6lowpan.h
act_api.h net/sched: actions: remove unused 'order' 2019-11-12 12:11:22 -08:00
addrconf.h ipv6: Annotate ipv6_addr_is_* bitwise pointer casts 2019-12-16 16:09:44 -08:00
af_ieee802154.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
af_rxrpc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
af_unix.h unix: Show number of pending scm files of receive queue in fdinfo 2019-12-12 17:04:55 -08:00
af_vsock.h vsock: add local transport support in the vsock core 2019-12-11 15:01:23 -08:00
ah.h
arp.h net: avoid potential false sharing in neighbor related code 2019-11-06 16:14:48 -08:00
atmclip.h
ax25.h ax25: fix possible use-after-free 2019-01-23 11:18:00 -08:00
ax88796.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
bond_3ad.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 90 2019-05-24 17:37:53 +02:00
bond_alb.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 5 2019-05-21 11:28:40 +02:00
bond_options.h bonding: add an option to specify a delay between peer notifications 2019-07-04 12:30:48 -07:00
bonding.h bonding: fix state transition issue in link monitoring 2019-11-05 17:40:16 -08:00
bpf_sk_storage.h bpf: support cloning sk storage on accept() 2019-08-17 23:18:54 +02:00
busy_poll.h net: annotate lockless accesses to sk->sk_napi_id 2019-10-30 17:34:35 -07:00
calipso.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
cfg80211-wext.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cfg80211.h A few big new things: 2020-02-16 19:00:22 -08:00
cfg802154.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
checksum.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cipso_ipv4.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
cls_cgroup.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
codel_impl.h
codel_qdisc.h
codel.h
compat.h net: rework SIOCGSTAMP ioctl handling 2019-04-19 14:07:40 -07:00
datalink.h
dcbevent.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 2019-05-30 11:29:52 -07:00
dcbnl.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 2019-05-30 11:29:52 -07:00
devlink.h devlink: add macro for "fw.roce" 2020-01-27 11:33:29 +01:00
dn_dev.h
dn_fib.h
dn_neigh.h
dn_nsp.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 24 2019-05-21 11:52:39 +02:00
dn_route.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 24 2019-05-21 11:52:39 +02:00
dn.h
drop_monitor.h drop_monitor: Add basic infrastructure for hardware drops 2019-08-17 12:40:08 -07:00
dsa.h net: dsa: Get information about stacked DSA protocol 2020-01-08 16:01:13 -08:00
dsfield.h ipv6: Annotate bitwise IPv6 dsfield pointer cast 2019-12-16 16:09:44 -08:00
dst_cache.h
dst_metadata.h
dst_ops.h net: add bool confirm_neigh parameter for dst_ops.update_pmtu 2019-12-24 22:28:54 -08:00
dst.h net/dst: do not confirm neighbor for vxlan and geneve pmtu update 2019-12-24 22:28:55 -08:00
erspan.h
esp.h
espintcp.h xfrm: add espintcp (RFC 8229) 2019-12-09 09:59:07 +01:00
ethoc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
failover.h net: Introduce generic failover module 2018-05-28 22:59:54 -04:00
fib_notifier.h ipv6: Remove old route notifications and convert listeners 2019-12-24 22:37:30 -08:00
fib_rules.h net: fib_notifier: propagate extack down to the notifier block callback 2019-10-04 11:10:56 -07:00
firewire.h
flow_dissector.h net/flow_dissector: remove unexist field description 2020-02-13 14:13:27 -08:00
flow_offload.h net: core: rename indirect block ingress cb function 2019-12-06 20:45:09 -08:00
flow.h route: Add multipath_hash in flowi_common to make user-define hash 2019-02-27 12:50:17 -08:00
fou.h
fq_impl.h net/fq_impl: Switch to kvmalloc() for memory allocation 2019-11-08 09:11:49 +01:00
fq.h net/flow_dissector: switch to siphash 2019-10-23 20:13:22 -07:00
garp.h treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
gen_stats.h net_sched: extend packet counter to 64bit 2019-11-05 18:20:55 -08:00
genetlink.h net: genetlink: remove unused genl_family_attrbuf() 2019-10-06 15:44:47 +02:00
geneve.h net: Move the definition of the default Geneve udp port to public header file 2019-03-22 12:09:31 -07:00
gre.h net: Add netif_is_gretap()/netif_is_ip6gretap() 2018-12-10 15:53:04 -08:00
gro_cells.h
gtp.h
gue.h net:gue.h:Fix shifting signed 32-bit value by 31 bits problem 2019-07-01 10:58:23 -07:00
hwbm.h net: hwbm: if CONFIG_NET_HWBM unset, make stub functions static 2019-10-25 16:24:32 -07:00
icmp.h icmp: introduce helper for nat'd source address in network device context 2020-02-13 14:19:00 -08:00
ieee80211_radiotap.h wireless-drivers-next patches for 5.1 2019-02-22 12:56:24 -08:00
ieee802154_netdev.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
if_inet6.h ipv6: shrink struct ipv6_mc_socklist 2019-08-28 14:43:03 -07:00
ife.h net: ife: drop include of module.h from net/ife.h 2019-04-22 21:50:53 -07:00
ila.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
inet6_connection_sock.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
inet6_hashtables.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
inet_common.h inet: factor out inet_send_prepare() 2019-07-03 13:51:54 -07:00
inet_connection_sock.h net/tls: use RCU protection on icsk->icsk_ulp_data 2019-08-31 23:44:28 -07:00
inet_ecn.h inet: Refactor INET_ECN_decapsulate() 2018-10-17 17:45:07 -07:00
inet_frag.h inet: frags: re-introduce skb coalescing for local delivery 2019-08-08 15:55:10 -07:00
inet_hashtables.h tcp/dccp: fix possible race __inet_lookup_established() 2019-12-13 21:40:49 -08:00
inet_sock.h ip: support SO_MARK cmsg 2019-09-13 21:44:19 +02:00
inet_timewait_sock.h tcp: honor SO_PRIORITY in TIME_WAIT state 2019-09-27 12:05:02 +02:00
inetpeer.h net: ipv4: use a dedicated counter for icmp_v4 redirect packets 2019-02-08 21:50:15 -08:00
ip6_checksum.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip6_fib.h ipv6: Add "offload" and "trap" indications to routes 2020-01-14 18:53:35 -08:00
ip6_route.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-27 21:06:39 -07:00
ip6_tunnel.h ip6_tunnel: allow not to count pkts on tstats by passing dev as NULL 2019-06-18 20:48:45 -04:00
ip_fib.h ipv4: Add "offload" and "trap" indications to routes 2020-01-14 18:53:35 -08:00
ip_tunnels.h treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
ip_vs.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-02 13:54:56 -07:00
ip.h inet: protect against too small mtu values. 2019-12-07 11:55:11 -08:00
ipcomp.h
ipconfig.h
ipv6_frag.h inet: fix various use-after-free in defrags units 2019-06-19 11:37:47 -04:00
ipv6_stubs.h net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup 2019-12-04 12:27:13 -08:00
ipv6.h mptcp: do not inherit inet proto ops 2020-01-25 08:14:39 +01:00
ipx.h bonding/alb: properly access headers in bond_alb_xmit() 2020-02-05 14:28:09 +01:00
iw_handler.h
kcm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
l3mdev.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
lag.h net: Add lag.h, net_lag_port_dev_txable() 2018-07-11 23:10:19 -07:00
lapb.h
lib80211.h
llc_c_ac.h
llc_c_ev.h
llc_c_st.h
llc_conn.h llc: fix sk_buff leak in llc_conn_service() 2019-10-08 13:23:05 -07:00
llc_if.h
llc_pdu.h
llc_s_ac.h
llc_s_ev.h
llc_s_st.h
llc_sap.h
llc.h llc: avoid blocking in llc_sap_close() 2018-09-13 09:04:58 -07:00
lwtunnel.h lwtunnel: Pass encap and encap type attributes to lwtunnel_fill_encap 2019-04-23 19:42:29 -07:00
mac80211.h A few big new things: 2020-02-16 19:00:22 -08:00
mac802154.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
macsec.h net: macsec: PN wrap callback 2020-01-14 11:31:41 -08:00
mip6.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
mld.h
mpls_iptunnel.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
mpls.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
mptcp.h mptcp: Fix undefined mptcp_handle_ipv6_mapped for modular IPV6 2020-01-30 10:55:54 +01:00
mrp.h treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
ncsi.h
ndisc.h net: avoid potential false sharing in neighbor related code 2019-11-06 16:14:48 -08:00
neighbour.h neighbour: remove neigh_cleanup() method 2019-12-09 09:48:47 -08:00
net_failover.h net: Introduce net_failover driver 2018-05-28 22:59:54 -04:00
net_namespace.h netns: Constify exported functions 2020-01-17 13:25:24 +01:00
net_ratelimit.h
netevent.h net: ipv4: Notify about changes to ip_forward_update_priority 2018-08-01 09:52:30 -07:00
netlabel.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
netlink.h netlink: rename nl80211_validate_nested() to nla_validate_nested() 2019-12-12 17:07:05 -08:00
netprio_cgroup.h netprio: use css ID instead of cgroup ID 2019-11-12 08:18:03 -08:00
netrom.h net: netrom: Fix error cleanup path of nr_proto_init 2019-04-11 13:59:49 -07:00
nexthop.h net: Properly update v4 routes with v6 nexthop 2019-09-05 12:35:58 +02:00
nl802154.h
nsh.h
p8022.h
page_pool.h net: page_pool: add the possibility to sync DMA memory for device 2019-11-20 12:34:28 -08:00
pie.h net: sched: add Flow Queue PIE packet scheduler 2020-01-23 11:38:31 +01:00
ping.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
pkt_cls.h net: sched: don't take rtnl lock during flow_action setup 2020-02-17 14:17:02 -08:00
pkt_sched.h Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2019-09-17 23:51:10 +02:00
pptp.h
protocol.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
psample.h net: sched: take reference to psample group in flow_action infra 2019-09-16 09:18:03 +02:00
psnap.h
raw.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
rawv6.h
red.h
regulatory.h cfg80211: make wmm_rule part of the reg_rule structure 2018-08-28 11:11:47 +02:00
request_sock.h net: add {READ|WRITE}_ONCE() annotations on ->rskq_accept_head 2019-10-09 21:34:31 -07:00
rose.h
route.h ipv4: use dst hint for ipv4 list receive 2019-11-21 14:45:55 -08:00
rsi_91x.h
rtnetlink.h net: Add extack argument to rtnl_create_link 2018-11-06 15:00:45 -08:00
rtnh.h net: Rename net/nexthop.h net/rtnh.h 2019-04-22 21:47:25 -07:00
sch_generic.h net_sched: fix ops->bind_class() implementations 2020-01-27 10:51:43 +01:00
scm.h pids: Compute task_tgid using signal->leader_pid 2018-07-21 10:43:12 -05:00
secure_seq.h
seg6_hmac.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
seg6_local.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
seg6.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
slhc_vj.h
smc.h net/smc: introduce bookkeeping of SMCD link groups 2019-11-15 12:28:28 -08:00
snmp.h net/tls: add skeleton of MIB statistics 2019-10-05 16:29:00 -07:00
sock_reuseport.h udp: correct reuseport selection with connected sockets 2019-09-16 09:02:18 +02:00
sock.h net, sk_msg: Clear sk_user_data pointer on clone if tagged 2020-02-21 22:29:45 +01:00
Space.h
stp.h
strparser.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
switchdev.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
tcp_states.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
tcp.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2020-01-23 08:10:16 +01:00
timewait_sock.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
tipc.h
tls_toe.h net/tls: rename tls_hw_* functions tls_toe_* 2019-10-04 14:07:07 -07:00
tls.h net/tls: add helper for testing if socket is RX offloaded 2019-12-19 17:46:51 -08:00
transp_v6.h ipv6: fold sockcm_cookie into ipcm6_cookie 2018-07-07 10:58:49 +09:00
tso.h
tun_proto.h
udp_tunnel.h ipv6: Move ipv6 stubs to a separate header file 2019-03-29 10:53:45 -07:00
udp.h udp: document udp_rcv_segment special case for looped packets 2020-01-30 09:59:53 +01:00
udplite.h
vsock_addr.h vsock: remove include/linux/vm_sockets.h file 2019-11-14 18:12:17 -08:00
vxlan.h vxlan: add adjacent link to limit depth level 2019-10-24 14:53:49 -07:00
wext.h
wimax.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 268 2019-06-05 17:30:29 +02:00
x25.h net/x25: add new state X25_STATE_5 2019-12-09 10:28:43 -08:00
x25device.h
xdp_priv.h page_pool: do not release pool until inflight == 0. 2019-11-16 12:39:10 -08:00
xdp_sock.h xsk: ixgbe: i40e: ice: mlx5: Xsk_umem_discard_addr to xsk_umem_release_addr 2019-12-20 16:00:09 -08:00
xdp.h xdp: page_pool related fix to cpumap 2019-06-19 11:23:13 -04:00
xfrm.h xfrm: add espintcp (RFC 8229) 2019-12-09 09:59:07 +01:00