linux-stable/net/ipv4
Eric Dumazet 4faeee0cf8 tcp: deny tcp_disconnect() when threads are waiting
Historically connect(AF_UNSPEC) has been abused by syzkaller
and other fuzzers to trigger various bugs.

A recent one triggers a divide-by-zero [1], and Paolo Abeni
was able to diagnose the issue.

tcp_recvmsg_locked() has tests about sk_state being not TCP_LISTEN
and TCP REPAIR mode being not used.

Then later if socket lock is released in sk_wait_data(),
another thread can call connect(AF_UNSPEC), then make this
socket a TCP listener.

When recvmsg() is resumed, it can eventually call tcp_cleanup_rbuf()
and attempt a divide by 0 in tcp_rcv_space_adjust() [1]

This patch adds a new socket field, counting number of threads
blocked in sk_wait_event() and inet_wait_for_connect().

If this counter is not zero, tcp_disconnect() returns an error.

This patch adds code in blocking socket system calls, thus should
not hurt performance of non blocking ones.

Note that we probably could revert commit 499350a5a6 ("tcp:
initialize rcv_mss to TCP_MIN_MSS instead of 0") to restore
original tcpi_rcv_mss meaning (was 0 if no payload was ever
received on a socket)

[1]
divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 13832 Comm: syz-executor.5 Not tainted 6.3.0-rc4-syzkaller-00224-g00c7b5f4ddc5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:tcp_rcv_space_adjust+0x36e/0x9d0 net/ipv4/tcp_input.c:740
Code: 00 00 00 00 fc ff df 4c 89 64 24 48 8b 44 24 04 44 89 f9 41 81 c7 80 03 00 00 c1 e1 04 44 29 f0 48 63 c9 48 01 e9 48 0f af c1 <49> f7 f6 48 8d 04 41 48 89 44 24 40 48 8b 44 24 30 48 c1 e8 03 48
RSP: 0018:ffffc900033af660 EFLAGS: 00010206
RAX: 4a66b76cbade2c48 RBX: ffff888076640cc0 RCX: 00000000c334e4ac
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 0000000000000001
RBP: 00000000c324e86c R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880766417f8
R13: ffff888028fbb980 R14: 0000000000000000 R15: 0000000000010344
FS: 00007f5bffbfe700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32f25000 CR3: 000000007ced0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
tcp_recvmsg_locked+0x100e/0x22e0 net/ipv4/tcp.c:2616
tcp_recvmsg+0x117/0x620 net/ipv4/tcp.c:2681
inet6_recvmsg+0x114/0x640 net/ipv6/af_inet6.c:670
sock_recvmsg_nosec net/socket.c:1017 [inline]
sock_recvmsg+0xe2/0x160 net/socket.c:1038
____sys_recvmsg+0x210/0x5a0 net/socket.c:2720
___sys_recvmsg+0xf2/0x180 net/socket.c:2762
do_recvmmsg+0x25e/0x6e0 net/socket.c:2856
__sys_recvmmsg net/socket.c:2935 [inline]
__do_sys_recvmmsg net/socket.c:2958 [inline]
__se_sys_recvmmsg net/socket.c:2951 [inline]
__x64_sys_recvmmsg+0x20f/0x260 net/socket.c:2951
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f5c0108c0f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5bffbfe168 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f5c011ac050 RCX: 00007f5c0108c0f9
RDX: 0000000000000001 RSI: 0000000020000bc0 RDI: 0000000000000003
RBP: 00007f5c010e7b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000122 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5c012cfb1f R14: 00007f5bffbfe300 R15: 0000000000022000
</TASK>

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot <syzkaller@googlegroups.com>
Reported-by: Paolo Abeni <pabeni@redhat.com>
Diagnosed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20230526163458.2880232-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-05-29 22:03:48 -07:00
..
bpfilter
netfilter xtables: move icmp/icmpv6 logic to xt_tcpudp 2023-03-22 21:48:59 +01:00
af_inet.c tcp: deny tcp_disconnect() when threads are waiting 2023-05-29 22:03:48 -07:00
ah4.c
arp.c neighbour: annotate lockless accesses to n->nud_state 2023-03-15 00:37:32 -07:00
bpf_tcp_ca.c bpf: Remove unused arguments from btf_struct_access(). 2023-04-04 16:57:10 -07:00
cipso_ipv4.c
datagram.c
devinet.c net: ipv4: Allow changing IPv4 address protocol 2023-03-23 08:32:52 +00:00
esp4.c
esp4_offload.c
fib_frontend.c ipv4: Fix incorrect table ID in IOCTL path 2023-03-16 17:26:31 -07:00
fib_lookup.h
fib_notifier.c
fib_rules.c
fib_semantics.c neighbour: switch to standard rcu, instead of rcu_bh 2023-03-21 21:32:18 -07:00
fib_trie.c
fou_bpf.c bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs 2023-04-12 16:40:39 -07:00
fou_core.c bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs 2023-04-12 16:40:39 -07:00
fou_nl.c ynl: broaden the license even more 2023-03-16 21:20:32 -07:00
fou_nl.h ynl: broaden the license even more 2023-03-16 21:20:32 -07:00
gre_demux.c
gre_offload.c
icmp.c icmp: guard against too small mtu 2023-03-31 21:37:06 -07:00
igmp.c ipv4: constify ip_mc_sf_allow() socket argument 2023-03-17 08:56:37 +00:00
inet_connection_sock.c tcp: deny tcp_disconnect() when threads are waiting 2023-05-29 22:03:48 -07:00
inet_diag.c
inet_fragment.c
inet_hashtables.c ipv6: Remove in6addr_any alternatives. 2023-03-29 08:22:52 +01:00
inet_timewait_sock.c
inetpeer.c
ip_forward.c
ip_fragment.c
ip_gre.c erspan: do not use skb_mac_header() in ndo_start_xmit() 2023-03-21 21:16:26 -07:00
ip_input.c
ip_options.c
ip_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-04-26 10:17:46 +02:00
ip_sockglue.c ipv{4,6}/raw: fix output xfrm lookup wrt protocol 2023-05-23 15:38:59 +02:00
ip_tunnel.c bpf-next-for-netdev 2023-04-13 16:43:38 -07:00
ip_tunnel_core.c
ip_vti.c
ipcomp.c
ipconfig.c
ipip.c ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices 2023-04-12 16:40:39 -07:00
ipmr.c
ipmr_base.c
Kconfig
Makefile bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs 2023-04-12 16:40:39 -07:00
metrics.c
netfilter.c
netlink.c
nexthop.c neighbour: switch to standard rcu, instead of rcu_bh 2023-03-21 21:32:18 -07:00
ping.c ping: Fix potentail NULL deref for /proc/net/icmp. 2023-04-04 18:56:58 -07:00
proc.c
protocol.c
raw.c ipv{4,6}/raw: fix output xfrm lookup wrt protocol 2023-05-23 15:38:59 +02:00
raw_diag.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-04-06 12:01:20 -07:00
route.c net: dst: fix missing initialization of rt_uncached 2023-04-21 20:26:56 -07:00
syncookies.c
sysctl_net_ipv4.c tcp: restrict net.ipv4.tcp_app_win 2023-04-07 08:19:11 +01:00
tcp.c tcp: deny tcp_disconnect() when threads are waiting 2023-05-29 22:03:48 -07:00
tcp_bbr.c
tcp_bic.c
tcp_bpf.c bpf, sockmap: Incorrectly handling copied_seq 2023-05-23 16:10:42 +02:00
tcp_cdg.c
tcp_cong.c net: Update an existing TCP congestion control algorithm. 2023-03-22 22:53:00 -07:00
tcp_cubic.c
tcp_dctcp.c
tcp_dctcp.h
tcp_diag.c
tcp_fastopen.c
tcp_highspeed.c
tcp_htcp.c
tcp_hybla.c
tcp_illinois.c
tcp_input.c tcp: add annotations around sk->sk_shutdown accesses 2023-05-10 10:27:31 +01:00
tcp_ipv4.c tcp: fix possible sk_priority leak in tcp_v4_send_reset() 2023-05-12 10:05:50 +01:00
tcp_lp.c
tcp_metrics.c
tcp_minisocks.c tcp: preserve const qualifier in tcp_sk() 2023-03-18 12:23:34 +00:00
tcp_nv.c
tcp_offload.c
tcp_output.c tcp: preserve const qualifier in tcp_sk() 2023-03-18 12:23:34 +00:00
tcp_plb.c
tcp_rate.c
tcp_recovery.c tcp: preserve const qualifier in tcp_sk() 2023-03-18 12:23:34 +00:00
tcp_scalable.c
tcp_timer.c tcp: annotate lockless access to sk->sk_err 2023-03-17 08:25:05 +00:00
tcp_ulp.c
tcp_vegas.c
tcp_vegas.h
tcp_veno.c
tcp_westwood.c
tcp_yeah.c
tunnel4.c
udp.c bpf, sockmap: Pass skb ownership through read_skb 2023-05-23 16:09:47 +02:00
udp_bpf.c bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser() 2023-03-03 17:25:15 +01:00
udp_diag.c
udp_impl.h
udp_offload.c
udp_tunnel_core.c
udp_tunnel_nic.c
udp_tunnel_stub.c
udplite.c udplite: Fix NULL pointer dereference in __sk_mem_raise_allocated(). 2023-05-25 10:51:58 +02:00
xfrm4_input.c
xfrm4_output.c
xfrm4_policy.c net: dst: fix missing initialization of rt_uncached 2023-04-21 20:26:56 -07:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c