linux/net/core
John Fastabend 144748eb0c bpf, sockmap: Fix incorrect fwd_alloc accounting
Incorrect accounting fwd_alloc can result in a warning when the socket
is torn down,

 [18455.319240] WARNING: CPU: 0 PID: 24075 at net/core/stream.c:208 sk_stream_kill_queues+0x21f/0x230
 [...]
 [18455.319543] Call Trace:
 [18455.319556]  inet_csk_destroy_sock+0xba/0x1f0
 [18455.319577]  tcp_rcv_state_process+0x1b4e/0x2380
 [18455.319593]  ? lock_downgrade+0x3a0/0x3a0
 [18455.319617]  ? tcp_finish_connect+0x1e0/0x1e0
 [18455.319631]  ? sk_reset_timer+0x15/0x70
 [18455.319646]  ? tcp_schedule_loss_probe+0x1b2/0x240
 [18455.319663]  ? lock_release+0xb2/0x3f0
 [18455.319676]  ? __release_sock+0x8a/0x1b0
 [18455.319690]  ? lock_downgrade+0x3a0/0x3a0
 [18455.319704]  ? lock_release+0x3f0/0x3f0
 [18455.319717]  ? __tcp_close+0x2c6/0x790
 [18455.319736]  ? tcp_v4_do_rcv+0x168/0x370
 [18455.319750]  tcp_v4_do_rcv+0x168/0x370
 [18455.319767]  __release_sock+0xbc/0x1b0
 [18455.319785]  __tcp_close+0x2ee/0x790
 [18455.319805]  tcp_close+0x20/0x80

This currently happens because on redirect case we do skb_set_owner_r()
with the original sock. This increments the fwd_alloc memory accounting
on the original sock. Then on redirect we may push this into the queue
of the psock we are redirecting to. When the skb is flushed from the
queue we give the memory back to the original sock. The problem is if
the original sock is destroyed/closed with skbs on another psocks queue
then the original sock will not have a way to reclaim the memory before
being destroyed. Then above warning will be thrown

  sockA                          sockB

  sk_psock_strp_read()
   sk_psock_verdict_apply()
     -- SK_REDIRECT --
     sk_psock_skb_redirect()
                                skb_queue_tail(psock_other->ingress_skb..)

  sk_close()
   sock_map_unref()
     sk_psock_put()
       sk_psock_drop()
         sk_psock_zap_ingress()

At this point we have torn down our own psock, but have the outstanding
skb in psock_other. Note that SK_PASS doesn't have this problem because
the sk_psock_drop() logic releases the skb, its still associated with
our psock.

To resolve lets only account for sockets on the ingress queue that are
still associated with the current socket. On the redirect case we will
check memory limits per 6fa9201a89, but will omit fwd_alloc accounting
until skb is actually enqueued. When the skb is sent via skb_send_sock_locked
or received with sk_psock_skb_ingress memory will be claimed on psock_other.

Fixes: 6fa9201a89 ("bpf, sockmap: Avoid returning unneeded EAGAIN when redirecting to self")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/161731444013.68884.4021114312848535993.stgit@john-XPS-13-9370
2021-04-07 01:29:06 +02:00
..
bpf_sk_storage.c bpf: Expose bpf_sk_storage_* to iterator programs 2020-12-04 22:32:40 +01:00
datagram.c udp: fix skb_copy_and_csum_datagram with odd segment sizes 2021-02-04 18:56:56 -08:00
datagram.h
dev_addr_lists.c net: core: add nested_level variable in net_device 2020-09-28 15:00:15 -07:00
dev_ioctl.c net: fix dev_ifsioc_locked() race condition 2021-02-11 18:14:19 -08:00
dev.c net: check all name nodes in __dev_alloc_name 2021-03-18 14:40:53 -07:00
devlink.c mlx5 subfunction support 2021-01-28 16:57:19 -08:00
drop_monitor.c drop_monitor: Perform cleanup upon probe registration failure 2021-03-10 15:19:02 -08:00
dst_cache.c
dst.c net, bpf: Fix ip6ip6 crash with collect_md populated skbs 2021-03-10 12:24:18 -08:00
failover.c
fib_notifier.c net: fib_notifier: propagate extack down to the notifier block callback 2019-10-04 11:10:56 -07:00
fib_rules.c treewide: rename nla_strlcpy to nla_strscpy. 2020-11-16 08:08:54 -08:00
filter.c bpf: BPF-helper for MTU checking add length input 2021-03-08 22:44:33 +01:00
flow_dissector.c flow_dissector: fix byteorder of dissected ICMP ID 2021-03-14 14:30:20 -07:00
flow_offload.c net: flow_offload: Fix memory leak for indirect flow block 2020-12-09 16:08:33 -08:00
gen_estimator.c net_sched: gen_estimator: support large ewma log 2021-01-15 18:11:06 -08:00
gen_stats.c docs: networking: convert gen_stats.txt to ReST 2020-04-28 14:39:46 -07:00
gro_cells.c gro_cells: reduce number of synchronize_net() calls 2020-11-25 11:28:12 -08:00
hwbm.c
link_watch.c net: Add IF_OPER_TESTING 2020-04-20 12:43:24 -07:00
lwt_bpf.c lwt_bpf: Replace preempt_disable() with migrate_disable() 2020-12-07 11:53:40 -08:00
lwtunnel.c net: ipv6: add rpl sr tunnel 2020-03-29 22:30:57 -07:00
Makefile ethtool: move to its own directory 2019-12-12 17:07:05 -08:00
neighbour.c neighbour: Disregard DEAD dst in neigh_update 2021-03-31 14:10:46 -07:00
net_namespace.c net: initialize net->net_cookie at netns setup 2021-02-11 14:10:07 -08:00
net-procfs.c net-sysfs: add backlog len and CPU id to softnet data 2020-09-21 13:56:37 -07:00
net-sysfs.c net: add sysfs attribute to control napi threaded mode 2021-02-09 15:27:28 -08:00
net-sysfs.h net-sysfs: add netdev_change_owner() 2020-02-26 20:07:25 -08:00
net-traces.c
netclassid_cgroup.c net: Remove the err argument from sock_from_file 2020-12-04 22:32:40 +01:00
netevent.c
netpoll.c Revert "net: Have netpoll bring-up DSA management interface" 2021-02-06 14:42:57 -08:00
netprio_cgroup.c net: Remove the err argument from sock_from_file 2020-12-04 22:32:40 +01:00
page_pool.c net: page_pool: simplify page recycling condition tests 2021-02-04 18:20:14 -08:00
pktgen.c pktgen: fix misuse of BUG_ON() in pktgen_thread_worker() 2021-01-27 16:46:37 -08:00
ptp_classifier.c ptp: Add generic ptp v2 header parsing function 2020-08-19 16:07:49 -07:00
request_sock.c tcp: add rcu protection around tp->fastopen_rsk 2019-10-13 10:13:08 -07:00
rtnetlink.c rtnetlink: using dev_base_seq from target net 2021-03-03 16:59:17 -08:00
scm.c fs: Add receive_fd() wrapper for __receive_fd() 2020-07-13 11:03:44 -07:00
secure_seq.c crypto: lib/sha1 - remove unnecessary includes of linux/cryptohash.h 2020-05-08 15:32:17 +10:00
skbuff.c net: expand textsearch ts_state to fit skb_seq_state 2021-03-01 15:25:24 -08:00
skmsg.c bpf, sockmap: Fix incorrect fwd_alloc accounting 2021-04-07 01:29:06 +02:00
sock_diag.c bpf, net: Rework cookie generator as per-cpu one 2020-09-30 11:50:35 -07:00
sock_map.c bpf: Replace fput with sockfd_put in sock map 2021-01-08 13:39:24 -08:00
sock_reuseport.c udp: Prevent reuseport_select_sock from reading uninitialized socks 2021-01-08 19:15:40 -08:00
sock.c net: let skb_orphan_partial wake-up waiters. 2021-03-30 13:57:28 -07:00
stream.c tcp: make sure EPOLLOUT wont be missed 2019-08-19 13:07:43 -07:00
sysctl_net_core.c net: sysctl: remove redundant #ifdef CONFIG_NET 2021-01-27 17:02:43 -08:00
timestamping.c net: Introduce a new MII time stamping interface. 2019-12-25 19:51:33 -08:00
tso.c net: tso: add UDP segmentation support 2020-06-18 20:46:23 -07:00
utils.c net: Fix skb->csum update in inet_proto_csum_replace16(). 2020-01-24 20:54:30 +01:00
xdp.c xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model 2021-03-31 15:15:23 -07:00