linux/net/sctp
Eric Dumazet 70c2655849 net: silence KCSAN warnings about sk->sk_backlog.len reads
sk->sk_backlog.len can be written by BH handlers, and read
from process contexts in a lockless way.

Note the write side should also use WRITE_ONCE() or a variant.
We need some agreement about the best way to do this.

syzbot reported :

BUG: KCSAN: data-race in tcp_add_backlog / tcp_grow_window.isra.0

write to 0xffff88812665f32c of 4 bytes by interrupt on cpu 1:
 sk_add_backlog include/net/sock.h:934 [inline]
 tcp_add_backlog+0x4a0/0xcc0 net/ipv4/tcp_ipv4.c:1737
 tcp_v4_rcv+0x1aba/0x1bf0 net/ipv4/tcp_ipv4.c:1925
 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204
 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523
 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004
 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5118
 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208
 napi_skb_finish net/core/dev.c:5671 [inline]
 napi_gro_receive+0x28f/0x330 net/core/dev.c:5704
 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061
 virtnet_receive drivers/net/virtio_net.c:1323 [inline]
 virtnet_poll+0x436/0x7d0 drivers/net/virtio_net.c:1428
 napi_poll net/core/dev.c:6352 [inline]
 net_rx_action+0x3ae/0xa50 net/core/dev.c:6418

read to 0xffff88812665f32c of 4 bytes by task 7292 on cpu 0:
 tcp_space include/net/tcp.h:1373 [inline]
 tcp_grow_window.isra.0+0x6b/0x480 net/ipv4/tcp_input.c:413
 tcp_event_data_recv+0x68f/0x990 net/ipv4/tcp_input.c:717
 tcp_rcv_established+0xbfe/0xf50 net/ipv4/tcp_input.c:5618
 tcp_v4_do_rcv+0x381/0x4e0 net/ipv4/tcp_ipv4.c:1542
 sk_backlog_rcv include/net/sock.h:945 [inline]
 __release_sock+0x135/0x1e0 net/core/sock.c:2427
 release_sock+0x61/0x160 net/core/sock.c:2943
 tcp_recvmsg+0x63b/0x1a30 net/ipv4/tcp.c:2181
 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838
 sock_recvmsg_nosec net/socket.c:871 [inline]
 sock_recvmsg net/socket.c:889 [inline]
 sock_recvmsg+0x92/0xb0 net/socket.c:885
 sock_read_iter+0x15f/0x1e0 net/socket.c:967
 call_read_iter include/linux/fs.h:1864 [inline]
 new_sync_read+0x389/0x4f0 fs/read_write.c:414
 __vfs_read+0xb1/0xc0 fs/read_write.c:427
 vfs_read fs/read_write.c:461 [inline]
 vfs_read+0x143/0x2c0 fs/read_write.c:446

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7292 Comm: syz-fuzzer Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
2019-10-09 21:43:00 -07:00
..
associola.c sctp: not set peer.asconf_capable in sctp_association_init 2019-08-19 18:27:28 -07:00
auth.c sctp: add sctp_auth_init and sctp_auth_free 2019-08-19 18:27:29 -07:00
bind_addr.c sctp: remove rcu_read_lock from sctp_bind_addr_state 2019-07-08 20:18:11 -07:00
chunk.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
debug.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
diag.c net: silence KCSAN warnings about sk->sk_backlog.len reads 2019-10-09 21:43:00 -07:00
endpointola.c sctp: make ecn flag per netns and endpoint 2019-08-27 20:54:14 -07:00
input.c net: silence KCSAN warnings around sk_add_backlog() calls 2019-10-09 21:42:59 -07:00
inqueue.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
ipv6.c ipv6: add priority parameter to ip6_xmit() 2019-09-27 12:05:02 +02:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile sctp: rename sctp_diag.c as diag.c 2018-02-13 13:56:31 -05:00
objcnt.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-07 11:00:14 -07:00
output.c sctp: count data bundling sack chunk for outctrlchunks 2019-07-03 11:41:24 -07:00
outqueue.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
primitive.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
proc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
protocol.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-15 14:17:27 +02:00
sm_make_chunk.c sctp: make ecn flag per netns and endpoint 2019-08-27 20:54:14 -07:00
sm_sideeffect.c sctp: use transport pf_retrans in sctp_do_8_2_transport_strike 2019-09-05 00:29:21 +02:00
sm_statefuns.c sctp: check asoc peer.asconf_capable before processing asconf 2019-08-19 18:27:28 -07:00
sm_statetable.c sctp: remove net sctp.x_enable working as a global switch 2019-08-19 18:27:29 -07:00
socket.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-15 14:17:27 +02:00
stream_interleave.c sctp: rename asoc intl_enable to asoc peer.intl_capable 2019-07-08 20:16:25 -07:00
stream_sched_prio.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
stream_sched_rr.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
stream_sched.c sctp: rename asoc intl_enable to asoc peer.intl_capable 2019-07-08 20:16:25 -07:00
stream.c sctp: fix memleak in sctp_send_reset_streams 2019-08-13 20:45:01 -07:00
sysctl.c sctp: allow users to set netns ecn flag with sysctl 2019-08-27 20:54:14 -07:00
transport.c sctp: only copy the available addr data in sctp_transport_init 2019-07-30 14:18:14 -07:00
tsnmap.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
ulpevent.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00
ulpqueue.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104 2019-05-24 17:39:00 +02:00