linux/net/ipv4
Kuniyuki Iwashima 5c0b485a8c udp: Set SOCK_RCU_FREE earlier in udp_lib_get_port().
syzkaller triggered the warning [0] in udp_v4_early_demux().

In udp_v[46]_early_demux() and sk_lookup(), we do not touch the refcount
of the looked-up sk and use sock_pfree() as skb->destructor, so we check
SOCK_RCU_FREE to ensure that the sk is safe to access during the RCU grace
period.

Currently, SOCK_RCU_FREE is flagged for a bound socket after being put
into the hash table.  Moreover, the SOCK_RCU_FREE check is done too early
in udp_v[46]_early_demux() and sk_lookup(), so there could be a small race
window:

  CPU1                                 CPU2
  ----                                 ----
  udp_v4_early_demux()                 udp_lib_get_port()
  |                                    |- hlist_add_head_rcu()
  |- sk = __udp4_lib_demux_lookup()    |
  |- DEBUG_NET_WARN_ON_ONCE(sk_is_refcounted(sk));
                                       `- sock_set_flag(sk, SOCK_RCU_FREE)

We had the same bug in TCP and fixed it in commit 871019b22d ("net:
set SOCK_RCU_FREE before inserting socket into hashtable").

Let's apply the same fix for UDP.

[0]:
WARNING: CPU: 0 PID: 11198 at net/ipv4/udp.c:2599 udp_v4_early_demux+0x481/0xb70 net/ipv4/udp.c:2599
Modules linked in:
CPU: 0 PID: 11198 Comm: syz-executor.1 Not tainted 6.9.0-g93bda33046e7 #13
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:udp_v4_early_demux+0x481/0xb70 net/ipv4/udp.c:2599
Code: c5 7a 15 fe bb 01 00 00 00 44 89 e9 31 ff d3 e3 81 e3 bf ef ff ff 89 de e8 2c 74 15 fe 85 db 0f 85 02 06 00 00 e8 9f 7a 15 fe <0f> 0b e8 98 7a 15 fe 49 8d 7e 60 e8 4f 39 2f fe 49 c7 46 60 20 52
RSP: 0018:ffffc9000ce3fa58 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8318c92c
RDX: ffff888036ccde00 RSI: ffffffff8318c2f1 RDI: 0000000000000001
RBP: ffff88805a2dd6e0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0001ffffffffffff R12: ffff88805a2dd680
R13: 0000000000000007 R14: ffff88800923f900 R15: ffff88805456004e
FS:  00007fc449127640(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc449126e38 CR3: 000000003de4b002 CR4: 0000000000770ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
PKRU: 55555554
Call Trace:
 <TASK>
 ip_rcv_finish_core.constprop.0+0xbdd/0xd20 net/ipv4/ip_input.c:349
 ip_rcv_finish+0xda/0x150 net/ipv4/ip_input.c:447
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ip_rcv+0x16c/0x180 net/ipv4/ip_input.c:569
 __netif_receive_skb_one_core+0xb3/0xe0 net/core/dev.c:5624
 __netif_receive_skb+0x21/0xd0 net/core/dev.c:5738
 netif_receive_skb_internal net/core/dev.c:5824 [inline]
 netif_receive_skb+0x271/0x300 net/core/dev.c:5884
 tun_rx_batched drivers/net/tun.c:1549 [inline]
 tun_get_user+0x24db/0x2c50 drivers/net/tun.c:2002
 tun_chr_write_iter+0x107/0x1a0 drivers/net/tun.c:2048
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x76f/0x8d0 fs/read_write.c:590
 ksys_write+0xbf/0x190 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x41/0x50 fs/read_write.c:652
 x64_sys_call+0xe66/0x1990 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x4b/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7fc44a68bc1f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 e9 cf f5 ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 3c d0 f5 ff 48
RSP: 002b:00007fc449126c90 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004bc050 RCX: 00007fc44a68bc1f
RDX: 0000000000000032 RSI: 00000000200000c0 RDI: 00000000000000c8
RBP: 00000000004bc050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000032 R11: 0000000000000293 R12: 0000000000000000
R13: 000000000000000b R14: 00007fc44a5ec530 R15: 0000000000000000
 </TASK>

Fixes: 6acc9b432e ("bpf: Add helper to retrieve socket in BPF")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20240709191356.24010-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-07-11 11:28:27 +02:00
..
netfilter netfilter: tproxy: bail out if IP has been disabled on the device 2024-05-29 00:37:51 +02:00
af_inet.c net: gro: initialize network_offset in network layer 2024-05-27 16:46:59 -07:00
ah4.c net: fill in MODULE_DESCRIPTION()s for ipv4 modules 2024-02-09 14:12:02 -08:00
arp.c arp: Convert ioctl(SIOCGARP) to RCU. 2024-05-01 18:37:07 -07:00
bpf_tcp_ca.c bpf: tcp: Allow to write tp->snd_cwnd_stamp in bpf_tcp_ca 2024-05-02 16:26:56 -07:00
cipso_ipv4.c cipso: make cipso_v4_skbuff_delattr() fully remove the CIPSO options 2024-06-14 08:19:54 +01:00
datagram.c ipv4: Set the routing scope properly in ip_route_output_ports(). 2024-02-12 17:33:05 -08:00
devinet.c rtnetlink: make the "split" NLM_DONE handling generic 2024-06-05 12:34:54 +01:00
esp4.c ipsec-next-2024-05-03 2024-05-06 19:14:56 -07:00
esp4_offload.c
fib_frontend.c rtnetlink: make the "split" NLM_DONE handling generic 2024-06-05 12:34:54 +01:00
fib_lookup.h
fib_notifier.c
fib_rules.c fib: remove unnecessary input parameters in fib_default_rule_add 2024-01-03 16:42:48 -08:00
fib_semantics.c net: add two more call_rcu_hurry() 2024-04-25 15:24:23 -07:00
fib_trie.c inet: switch inet_dump_fib() to RCU protection 2024-02-26 11:46:13 +00:00
fou_bpf.c ip_tunnel: convert __be16 tunnel flags to bitmaps 2024-04-01 10:49:28 +01:00
fou_core.c net: gro: rename skb_gro_header_hard() 2024-03-05 13:30:11 +01:00
fou_nl.c
fou_nl.h
gre_demux.c ip_tunnel: convert __be16 tunnel flags to bitmaps 2024-04-01 10:49:28 +01:00
gre_offload.c net: gro: rename skb_gro_header_hard() 2024-03-05 13:30:11 +01:00
icmp.c net/ipv4: add tracepoint for icmp_send 2024-05-08 10:39:26 +01:00
igmp.c ipv4: Set scope explicitly in ip_route_output(). 2024-04-08 13:20:51 +01:00
inet_connection_sock.c Fix race for duplicate reqsk on identical SYN 2024-06-25 11:37:45 +02:00
inet_diag.c inet_diag: Initialize pad field in struct inet_diag_req_v2 2024-07-04 15:25:09 +02:00
inet_fragment.c inet: frags: delay fqdir_free_fn() 2024-04-08 10:59:56 +01:00
inet_hashtables.c tcp: get rid of twsk_unique() 2024-05-09 20:25:55 -07:00
inet_timewait_sock.c tcp/dccp: do not care about families in inet_twsk_purge() 2024-04-01 21:27:58 -07:00
inetpeer.c net: ipv4: Simplify the allocation of slab caches in inet_initpeers 2024-01-31 16:39:42 -08:00
ip_forward.c
ip_fragment.c net: ipv{6,4}: Remove the now superfluous sentinel elements from ctl_table array 2024-05-03 13:29:42 +01:00
ip_gre.c net: annotate writes on dev->mtu from ndo_change_mtu() 2024-05-07 16:19:14 -07:00
ip_input.c inet: introduce dst_rtable() helper 2024-04-30 18:32:38 -07:00
ip_options.c
ip_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-05-02 12:06:25 -07:00
ip_sockglue.c inet: Add getsockopt support for IP_ROUTER_ALERT and IPV6_ROUTER_ALERT 2024-03-06 12:37:06 +00:00
ip_tunnel.c net: annotate writes on dev->mtu from ndo_change_mtu() 2024-05-07 16:19:14 -07:00
ip_tunnel_core.c ip_tunnel: convert __be16 tunnel flags to bitmaps 2024-04-01 10:49:28 +01:00
ip_vti.c ip_tunnel: convert __be16 tunnel flags to bitmaps 2024-04-01 10:49:28 +01:00
ipcomp.c
ipconfig.c
ipip.c ip_tunnel: convert __be16 tunnel flags to bitmaps 2024-04-01 10:49:28 +01:00
ipmr.c ip_tunnel: use a separate struct to store tunnel params in the kernel 2024-04-01 10:49:28 +01:00
ipmr_base.c
Kconfig
Makefile bpfilter: remove bpfilter 2024-01-04 10:23:10 -08:00
metrics.c
netfilter.c
netlink.c
nexthop.c nexthop: fix uninitialized variable in nla_put_nh_group_stats() 2024-03-22 18:03:29 -07:00
ping.c
proc.c net: add <net/proto_memory.h> 2024-04-30 18:46:52 -07:00
protocol.c
raw.c ipv4: Fix uninit-value access in __ip_make_skb() 2024-05-02 10:16:35 +02:00
raw_diag.c inet_diag: add module pointer to "struct inet_diag_handler" 2024-01-23 15:13:54 +01:00
route.c net: fix __dst_negative_advice() race 2024-05-29 17:34:49 -07:00
syncookies.c tcp: annotate data-races around tp->window_clamp 2024-04-05 22:32:37 -07:00
sysctl_net_ipv4.c net: ipv{6,4}: Remove the now superfluous sentinel elements from ctl_table array 2024-05-03 13:29:42 +01:00
tcp.c tcp: count CLOSE-WAIT sockets for TCP_MIB_CURRESTAB 2024-06-05 12:32:46 +01:00
tcp_ao.c net/tcp_ao: Don't leak ao_info on error-path 2024-06-19 17:30:19 -07:00
tcp_bbr.c tcp: Add new args for cong_control in tcp_congestion_ops 2024-05-02 16:26:56 -07:00
tcp_bic.c
tcp_bpf.c
tcp_cdg.c
tcp_cong.c bpf, net: validate struct_ops when updating value. 2024-03-04 10:03:57 -08:00
tcp_cubic.c bpf: Remove CONFIG_X86 and CONFIG_DYNAMIC_FTRACE guard from the tcp-cc kfuncs 2024-03-28 18:31:40 -07:00
tcp_dctcp.c tcp: Fix shift-out-of-bounds in dctcp_update_alpha(). 2024-05-21 13:34:50 +02:00
tcp_dctcp.h
tcp_diag.c inet_diag: add module pointer to "struct inet_diag_handler" 2024-01-23 15:13:54 +01:00
tcp_fastopen.c
tcp_highspeed.c
tcp_htcp.c
tcp_hybla.c
tcp_illinois.c
tcp_input.c tcp: fix incorrect undo caused by DSACK of TLP retransmit 2024-07-05 18:03:44 -07:00
tcp_ipv4.c tcp: reduce accepted window in NEW_SYN_RECV state 2024-05-27 16:47:23 -07:00
tcp_lp.c
tcp_metrics.c tcp_metrics: validate source addr length 2024-07-01 09:40:36 +01:00
tcp_minisocks.c tcp: reduce accepted window in NEW_SYN_RECV state 2024-05-27 16:47:23 -07:00
tcp_nv.c
tcp_offload.c net: gro: move L3 flush checks to tcp_gro_receive and udp_gro_receive_segment 2024-05-13 14:44:06 -07:00
tcp_output.c tcp: remove 64 KByte limit for initial tp->rcv_wnd value 2024-05-23 12:21:17 +02:00
tcp_plb.c
tcp_rate.c
tcp_recovery.c
tcp_scalable.c
tcp_sigpool.c net/tcp_sigpool: Use kref_get_unless_zero() 2024-01-01 14:42:05 +00:00
tcp_timer.c tcp: avoid too many retransmit packets 2024-07-10 19:05:27 -07:00
tcp_ulp.c
tcp_vegas.c
tcp_vegas.h
tcp_veno.c
tcp_westwood.c
tcp_yeah.c
tunnel4.c net: fill in MODULE_DESCRIPTION()s for ipv4 modules 2024-02-09 14:12:02 -08:00
udp.c udp: Set SOCK_RCU_FREE earlier in udp_lib_get_port(). 2024-07-11 11:28:27 +02:00
udp_bpf.c
udp_diag.c inet_diag: add module pointer to "struct inet_diag_handler" 2024-01-23 15:13:54 +01:00
udp_impl.h
udp_offload.c net: gro: move L3 flush checks to tcp_gro_receive and udp_gro_receive_segment 2024-05-13 14:44:06 -07:00
udp_tunnel_core.c ip_tunnel: convert __be16 tunnel flags to bitmaps 2024-04-01 10:49:28 +01:00
udp_tunnel_nic.c
udp_tunnel_stub.c
udplite.c
xfrm4_input.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-05-09 10:01:01 -07:00
xfrm4_output.c
xfrm4_policy.c net: ipv{6,4}: Remove the now superfluous sentinel elements from ctl_table array 2024-05-03 13:29:42 +01:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c net: fill in MODULE_DESCRIPTION()s for ipv4 modules 2024-02-09 14:12:02 -08:00