linux/net/ipv4
Kuniyuki Iwashima 6e48faad92 tcp: Use refcount_inc_not_zero() in tcp_twsk_unique().
[ Upstream commit f2db7230f7 ]

Anderson Nascimento reported a use-after-free splat in tcp_twsk_unique()
with nice analysis.

Since commit ec94c2696f ("tcp/dccp: avoid one atomic operation for
timewait hashdance"), inet_twsk_hashdance() sets TIME-WAIT socket's
sk_refcnt after putting it into ehash and releasing the bucket lock.

Thus, there is a small race window where other threads could try to
reuse the port during connect() and call sock_hold() in tcp_twsk_unique()
for the TIME-WAIT socket with zero refcnt.

If that happens, the refcnt taken by tcp_twsk_unique() is overwritten
and sock_put() will cause underflow, triggering a real use-after-free
somewhere else.

To avoid the use-after-free, we need to use refcount_inc_not_zero() in
tcp_twsk_unique() and give up on reusing the port if it returns false.

[0]:
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 1039313 at lib/refcount.c:25 refcount_warn_saturate+0xe5/0x110
CPU: 0 PID: 1039313 Comm: trigger Not tainted 6.8.6-200.fc39.x86_64 #1
Hardware name: VMware, Inc. VMware20,1/440BX Desktop Reference Platform, BIOS VMW201.00V.21805430.B64.2305221830 05/22/2023
RIP: 0010:refcount_warn_saturate+0xe5/0x110
Code: 42 8e ff 0f 0b c3 cc cc cc cc 80 3d aa 13 ea 01 00 0f 85 5e ff ff ff 48 c7 c7 f8 8e b7 82 c6 05 96 13 ea 01 01 e8 7b 42 8e ff <0f> 0b c3 cc cc cc cc 48 c7 c7 50 8f b7 82 c6 05 7a 13 ea 01 01 e8
RSP: 0018:ffffc90006b43b60 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff888009bb3ef0 RCX: 0000000000000027
RDX: ffff88807be218c8 RSI: 0000000000000001 RDI: ffff88807be218c0
RBP: 0000000000069d70 R08: 0000000000000000 R09: ffffc90006b439f0
R10: ffffc90006b439e8 R11: 0000000000000003 R12: ffff8880029ede84
R13: 0000000000004e20 R14: ffffffff84356dc0 R15: ffff888009bb3ef0
FS:  00007f62c10926c0(0000) GS:ffff88807be00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020ccb000 CR3: 000000004628c005 CR4: 0000000000f70ef0
PKRU: 55555554
Call Trace:
 <TASK>
 ? refcount_warn_saturate+0xe5/0x110
 ? __warn+0x81/0x130
 ? refcount_warn_saturate+0xe5/0x110
 ? report_bug+0x171/0x1a0
 ? refcount_warn_saturate+0xe5/0x110
 ? handle_bug+0x3c/0x80
 ? exc_invalid_op+0x17/0x70
 ? asm_exc_invalid_op+0x1a/0x20
 ? refcount_warn_saturate+0xe5/0x110
 tcp_twsk_unique+0x186/0x190
 __inet_check_established+0x176/0x2d0
 __inet_hash_connect+0x74/0x7d0
 ? __pfx___inet_check_established+0x10/0x10
 tcp_v4_connect+0x278/0x530
 __inet_stream_connect+0x10f/0x3d0
 inet_stream_connect+0x3a/0x60
 __sys_connect+0xa8/0xd0
 __x64_sys_connect+0x18/0x20
 do_syscall_64+0x83/0x170
 entry_SYSCALL_64_after_hwframe+0x78/0x80
RIP: 0033:0x7f62c11a885d
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 8b 0d a3 45 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007f62c1091e58 EFLAGS: 00000296 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000020ccb004 RCX: 00007f62c11a885d
RDX: 0000000000000010 RSI: 0000000020ccb000 RDI: 0000000000000003
RBP: 00007f62c1091e90 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 00007f62c10926c0
R13: ffffffffffffff88 R14: 0000000000000000 R15: 00007ffe237885b0
 </TASK>

Fixes: ec94c2696f ("tcp/dccp: avoid one atomic operation for timewait hashdance")
Reported-by: Anderson Nascimento <anderson@allelesecurity.com>
Closes: https://lore.kernel.org/netdev/37a477a6-d39e-486b-9577-3463f655a6b7@allelesecurity.com/
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240501213145.62261-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-05-17 12:02:20 +02:00
..
bpfilter net: Use umd_cleanup_helper() 2023-05-31 13:06:57 +02:00
netfilter netfilter: complete validation of user input 2024-04-17 11:19:30 +02:00
af_inet.c net: gro: fix udp bad offset in socket lookup by adding {inner_}network_offset to napi_gro_cb 2024-05-17 12:02:07 +02:00
ah4.c net: ipv4: Remove completion function scaffolding 2023-02-13 18:35:15 +08:00
arp.c arp: Prevent overflow in arp_req_get(). 2024-03-01 13:35:08 +01:00
bpf_tcp_ca.c bpf: Drop useless btf_vmlinux in bpf_tcp_ca 2023-07-18 17:31:10 -07:00
cipso_ipv4.c inet: move inet->is_icsk to inet->inet_flags 2023-08-16 11:09:17 +01:00
datagram.c ipv4: fix data-races around inet->inet_id 2023-08-20 11:40:49 +01:00
devinet.c ipv4: properly combine dev_base_seq and ipv4.dev_addr_genid 2024-03-01 13:35:07 +01:00
esp4_offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-06-22 18:40:38 -07:00
esp4.c net: esp: fix bad handling of pages from page_pool 2024-04-03 15:28:35 +02:00
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 ipv4: fib: annotate races around nh->nh_saddr_genid and nh->nh_saddr 2023-10-18 18:11:31 -07:00
fib_trie.c ipv4/fib: send notify when delete source address routes 2023-10-03 09:00:40 +02:00
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 net: ynl: prefix uAPI header include with uapi/ 2023-05-26 10:30:14 +01:00
fou_nl.h net: ynl: prefix uAPI header include with uapi/ 2023-05-26 10:30:14 +01:00
gre_demux.c
gre_offload.c net: move gso declarations and functions to their own files 2023-06-10 00:11:41 -07:00
icmp.c icmp: prevent possible NULL dereferences from icmp_build_probe() 2024-05-02 16:32:35 +02:00
igmp.c ipv4: igmp: fix refcnt uaf issue when receiving igmp query packet 2023-12-08 08:52:21 +01:00
inet_connection_sock.c tcp: Fix bind() regression for v6-only wildcard and v4(-mapped-v6) non-wildcard addresses. 2024-04-10 16:35:53 +02:00
inet_diag.c inet_diag: annotate data-races around inet_diag_table[] 2024-03-26 18:19:22 -04:00
inet_fragment.c inet: inet_defrag: prevent sk release while still in use 2024-04-10 16:35:44 +02:00
inet_hashtables.c tcp: Fix refcnt handling in __inet_hash_connect(). 2024-03-26 18:20:08 -04:00
inet_timewait_sock.c tcp: Fix NEW_SYN_RECV handling in inet_twsk_purge() 2024-03-26 18:20:07 -04:00
inetpeer.c
ip_forward.c net: ipv4, ipv6: fix IPSTATS_MIB_OUTOCTETS increment duplicated 2023-08-30 09:44:09 +01:00
ip_fragment.c inet: inet_defrag: prevent sk release while still in use 2024-04-10 16:35:44 +02:00
ip_gre.c erspan: make sure erspan_base_hdr is present in skb->head 2024-04-10 16:35:53 +02:00
ip_input.c ipv4: ignore dst hint for multipath routes 2023-09-01 08:11:51 +01:00
ip_options.c
ip_output.c ipv4: Fix uninit-value access in __ip_make_skb() 2024-05-17 12:02:07 +02:00
ip_sockglue.c ipmr: fix kernel panic when forwarding mcast packets 2024-02-05 20:14:35 +00:00
ip_tunnel_core.c tunnels: fix out of bounds access when building IPv6 PMTU error 2024-02-16 19:10:48 +01:00
ip_tunnel.c net: add netdev_lockdep_set_classes() to virtual drivers 2024-04-13 13:07:30 +02:00
ip_vti.c ip_vti: fix potential slab-use-after-free in decode_session6 2023-07-11 11:06:08 +02:00
ipcomp.c xfrm: ipcomp: add extack to ipcomp{4,6}_init_state 2022-09-29 07:18:00 +02:00
ipconfig.c net: ipconfig: move ic_nameservers_fallback into #ifdef block 2023-05-22 11:17:55 +01:00
ipip.c ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices 2023-04-12 16:40:39 -07:00
ipmr_base.c
ipmr.c ipmr: fix incorrect parameter validation in the ip_mroute_getsockopt() function 2024-03-26 18:19:40 -04:00
Kconfig tcp: configurable source port perturb table size 2022-11-16 13:02:04 +00:00
Makefile bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs 2023-04-12 16:40:39 -07:00
metrics.c ipv4: prevent potential spectre v1 gadget in ip_metrics_convert() 2023-01-23 21:37:25 -08:00
netfilter.c
netlink.c
nexthop.c nexthop: Do not increment dump sentinel at the end of the dump 2023-08-15 18:54:53 -07:00
ping.c bpf: Propagate modified uaddrlen from cgroup sockaddr programs 2024-01-31 16:19:04 -08:00
proc.c net: fix IPSTATS_MIB_OUTPKGS increment in OutForwDatagrams. 2024-04-03 15:28:39 +02:00
protocol.c
raw_diag.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-04-06 12:01:20 -07:00
raw.c ipv4: Fix uninit-value access in __ip_make_skb() 2024-05-17 12:02:07 +02:00
route.c ipv4: check for NULL idev in ip_route_use_hint() 2024-05-02 16:32:36 +02:00
syncookies.c tcp: fix cookie_init_timestamp() overflows 2023-11-20 11:59:01 +01:00
sysctl_net_ipv4.c networking: Update to register_net_sysctl_sz 2023-08-15 15:26:18 -07:00
tcp_bbr.c bpf: Add __bpf_kfunc tag to all kfuncs 2023-02-02 00:25:14 +01:00
tcp_bic.c
tcp_bpf.c tcp_bpf: properly release resources on error paths 2023-10-18 18:09:31 -07:00
tcp_cdg.c Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
tcp_cong.c net: Update an existing TCP congestion control algorithm. 2023-03-22 22:53:00 -07:00
tcp_cubic.c bpf: Add __bpf_kfunc tag to all kfuncs 2023-02-02 00:25:14 +01:00
tcp_dctcp.c bpf: Add __bpf_kfunc tag to all kfuncs 2023-02-02 00:25:14 +01:00
tcp_dctcp.h
tcp_diag.c tcp: Access &tcp_hashinfo via net. 2022-09-20 10:21:49 -07:00
tcp_fastopen.c inet: move inet->defer_connect to inet->inet_flags 2023-08-16 11:09:18 +01:00
tcp_highspeed.c
tcp_htcp.c
tcp_hybla.c
tcp_illinois.c
tcp_input.c tcp: defer shutdown(SEND_SHUTDOWN) for TCP_SYN_RECV sockets 2024-05-17 12:02:20 +02:00
tcp_ipv4.c tcp: Use refcount_inc_not_zero() in tcp_twsk_unique(). 2024-05-17 12:02:20 +02:00
tcp_lp.c
tcp_metrics.c tcp_metrics: do not create an entry from tcp_init_metrics() 2023-11-20 11:58:59 +01:00
tcp_minisocks.c rds: tcp: Fix use-after-free of net in reqsk_timer_handler(). 2024-03-26 18:20:08 -04:00
tcp_nv.c
tcp_offload.c net: move gso declarations and functions to their own files 2023-06-10 00:11:41 -07:00
tcp_output.c tcp: defer shutdown(SEND_SHUTDOWN) for TCP_SYN_RECV sockets 2024-05-17 12:02:20 +02:00
tcp_plb.c prandom: remove prandom_u32_max() 2022-12-20 03:13:45 +01:00
tcp_rate.c
tcp_recovery.c tcp: fix excessive TLP and RACK timeouts from HZ rounding 2023-10-17 17:25:42 -07:00
tcp_scalable.c
tcp_timer.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-18 12:44:56 -07:00
tcp_ulp.c net/ulp: use consistent error code when blocking ULP 2023-01-19 09:26:16 -08:00
tcp_vegas.c
tcp_vegas.h
tcp_veno.c
tcp_westwood.c
tcp_yeah.c
tcp.c tcp: defer shutdown(SEND_SHUTDOWN) for TCP_SYN_RECV sockets 2024-05-17 12:02:20 +02:00
tunnel4.c
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: Access &udp_table via net. 2022-11-16 09:43:35 +00:00
udp_impl.h sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES) 2023-06-24 15:50:13 -07:00
udp_offload.c net: gro: add flush check in udp_gro_receive_segment 2024-05-17 12:02:07 +02:00
udp_tunnel_core.c udp: lockless UDP_ENCAP_L2TPINUDP / UDP_GRO 2023-11-20 11:58:56 +01:00
udp_tunnel_nic.c udp_tunnel: Add checks for nla_nest_start() in __udp_tunnel_nic_dump_write() 2022-11-29 08:44:24 -08:00
udp_tunnel_stub.c
udp.c net: gro: fix udp bad offset in socket lookup by adding {inner_}network_offset to napi_gro_cb 2024-05-17 12:02:07 +02:00
udplite.c udplite: remove UDPLITE_BIT 2023-11-20 11:58:56 +01:00
xfrm4_input.c xfrm: Preserve vlan tags for transport mode software GRO 2024-05-17 12:02:20 +02:00
xfrm4_output.c
xfrm4_policy.c sysctl-6.6-rc1 2023-08-29 17:39:15 -07:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c xfrm: tunnel: add extack to ipip_init_state, xfrm6_tunnel_init_state 2022-09-29 07:18:00 +02:00