linux/net
Paolo Abeni 3d041393ea mptcp: prevent MPC handshake on port-based signal endpoints
Syzkaller reported a lockdep splat:

  ============================================
  WARNING: possible recursive locking detected
  6.11.0-rc6-syzkaller-00019-g67784a74e258 #0 Not tainted
  --------------------------------------------
  syz-executor364/5113 is trying to acquire lock:
  ffff8880449f1958 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
  ffff8880449f1958 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2328

  but task is already holding lock:
  ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
  ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2328

  other info that might help us debug this:
   Possible unsafe locking scenario:

         CPU0
         ----
    lock(k-slock-AF_INET);
    lock(k-slock-AF_INET);

   *** DEADLOCK ***

   May be due to missing lock nesting notation

  7 locks held by syz-executor364/5113:
   #0: ffff8880449f0e18 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1607 [inline]
   #0: ffff8880449f0e18 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_sendmsg+0x153/0x1b10 net/mptcp/protocol.c:1806
   #1: ffff88803fe39ad8 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1607 [inline]
   #1: ffff88803fe39ad8 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_sendmsg_fastopen+0x11f/0x530 net/mptcp/protocol.c:1727
   #2: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
   #2: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
   #2: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x5f/0x1b80 net/ipv4/ip_output.c:470
   #3: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
   #3: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
   #3: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x45f/0x1390 net/ipv4/ip_output.c:228
   #4: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
   #4: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x33b/0x15b0 net/core/dev.c:6104
   #5: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
   #5: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
   #5: ffffffff8e938320 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0x230/0x5f0 net/ipv4/ip_input.c:232
   #6: ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
   #6: ffff88803fe3cb58 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2328

  stack backtrace:
  CPU: 0 UID: 0 PID: 5113 Comm: syz-executor364 Not tainted 6.11.0-rc6-syzkaller-00019-g67784a74e258 #0
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
  Call Trace:
   <IRQ>
   __dump_stack lib/dump_stack.c:93 [inline]
   dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
   check_deadlock kernel/locking/lockdep.c:3061 [inline]
   validate_chain+0x15d3/0x5900 kernel/locking/lockdep.c:3855
   __lock_acquire+0x137a/0x2040 kernel/locking/lockdep.c:5142
   lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
   __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
   _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
   spin_lock include/linux/spinlock.h:351 [inline]
   sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2328
   mptcp_sk_clone_init+0x32/0x13c0 net/mptcp/protocol.c:3279
   subflow_syn_recv_sock+0x931/0x1920 net/mptcp/subflow.c:874
   tcp_check_req+0xfe4/0x1a20 net/ipv4/tcp_minisocks.c:853
   tcp_v4_rcv+0x1c3e/0x37f0 net/ipv4/tcp_ipv4.c:2267
   ip_protocol_deliver_rcu+0x22e/0x440 net/ipv4/ip_input.c:205
   ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233
   NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
   NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
   __netif_receive_skb_one_core net/core/dev.c:5661 [inline]
   __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5775
   process_backlog+0x662/0x15b0 net/core/dev.c:6108
   __napi_poll+0xcb/0x490 net/core/dev.c:6772
   napi_poll net/core/dev.c:6841 [inline]
   net_rx_action+0x89b/0x1240 net/core/dev.c:6963
   handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
   do_softirq+0x11b/0x1e0 kernel/softirq.c:455
   </IRQ>
   <TASK>
   __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
   local_bh_enable include/linux/bottom_half.h:33 [inline]
   rcu_read_unlock_bh include/linux/rcupdate.h:908 [inline]
   __dev_queue_xmit+0x1763/0x3e90 net/core/dev.c:4450
   dev_queue_xmit include/linux/netdevice.h:3105 [inline]
   neigh_hh_output include/net/neighbour.h:526 [inline]
   neigh_output include/net/neighbour.h:540 [inline]
   ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:235
   ip_local_out net/ipv4/ip_output.c:129 [inline]
   __ip_queue_xmit+0x118c/0x1b80 net/ipv4/ip_output.c:535
   __tcp_transmit_skb+0x2544/0x3b30 net/ipv4/tcp_output.c:1466
   tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6542 [inline]
   tcp_rcv_state_process+0x2c32/0x4570 net/ipv4/tcp_input.c:6729
   tcp_v4_do_rcv+0x77d/0xc70 net/ipv4/tcp_ipv4.c:1934
   sk_backlog_rcv include/net/sock.h:1111 [inline]
   __release_sock+0x214/0x350 net/core/sock.c:3004
   release_sock+0x61/0x1f0 net/core/sock.c:3558
   mptcp_sendmsg_fastopen+0x1ad/0x530 net/mptcp/protocol.c:1733
   mptcp_sendmsg+0x1884/0x1b10 net/mptcp/protocol.c:1812
   sock_sendmsg_nosec net/socket.c:730 [inline]
   __sock_sendmsg+0x1a6/0x270 net/socket.c:745
   ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597
   ___sys_sendmsg net/socket.c:2651 [inline]
   __sys_sendmmsg+0x3b2/0x740 net/socket.c:2737
   __do_sys_sendmmsg net/socket.c:2766 [inline]
   __se_sys_sendmmsg net/socket.c:2763 [inline]
   __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2763
   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
   do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
  RIP: 0033:0x7f04fb13a6b9
  Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 01 1a 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:00007ffd651f42d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
  RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f04fb13a6b9
  RDX: 0000000000000001 RSI: 0000000020000d00 RDI: 0000000000000004
  RBP: 00007ffd651f4310 R08: 0000000000000001 R09: 0000000000000001
  R10: 0000000020000080 R11: 0000000000000246 R12: 00000000000f4240
  R13: 00007f04fb187449 R14: 00007ffd651f42f4 R15: 00007ffd651f4300
   </TASK>

As noted by Cong Wang, the splat is false positive, but the code
path leading to the report is an unexpected one: a client is
attempting an MPC handshake towards the in-kernel listener created
by the in-kernel PM for a port based signal endpoint.

Such connection will be never accepted; many of them can make the
listener queue full and preventing the creation of MPJ subflow via
such listener - its intended role.

Explicitly detect this scenario at initial-syn time and drop the
incoming MPC request.

Fixes: 1729cf186d ("mptcp: create the listening socket for new port")
Cc: stable@vger.kernel.org
Reported-by: syzbot+f4aacdfef2c6a6529c3e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f4aacdfef2c6a6529c3e
Cc: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241014-net-mptcp-mpc-port-endp-v2-1-7faea8e6b6ae@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-15 10:57:02 -07:00
..
6lowpan ipv6: eliminate ndisc_ops_is_useropt() 2024-08-12 17:23:57 -07:00
9p net/9p/usbg: fix CONFIG_USB_GADGET dependency 2024-09-11 15:59:43 +02:00
802 move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
8021q netdev_features: remove NETIF_F_ALL_FCOE 2024-09-03 11:36:43 +02:00
appletalk Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-05-09 10:01:01 -07:00
atm atm: clean up a put_user() calls 2024-06-14 19:08:50 -07:00
ax25 ax25: Replace kfree() in ax25_dev_free() with ax25_dev_put() 2024-06-01 15:49:42 -07:00
batman-adv move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
bluetooth Bluetooth: hci_conn: Fix UAF in hci_enhanced_setup_sync 2024-10-04 16:54:17 -04:00
bpf bpf: use type_may_be_null() helper for nullable-param check 2024-09-05 13:29:06 -07:00
bridge bridge: Handle error of rtnl_register_module(). 2024-10-10 15:39:35 +02:00
caif move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
can Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-15 09:13:19 -07:00
ceph libceph: use min() to simplify code in ceph_dns_resolve_name() 2024-08-27 09:30:16 +02:00
core rtnetlink: Add bulk registration helpers for rtnetlink message handlers. 2024-10-10 15:39:35 +02:00
dcb
dccp move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
devlink devlink: Constify the 'table_ops' parameter of devl_dpipe_table_register() 2024-06-05 10:24:57 +01:00
dns_resolver
dsa net: dsa: refuse cross-chip mirroring operations 2024-10-09 19:41:35 -07:00
ethernet netkit: Fix pkt_type override upon netkit pass verdict 2024-05-25 10:48:57 -07:00
ethtool net: ethtool: phy: Don't set the context dev pointer for unfiltered DUMP 2024-09-13 21:40:12 -07:00
handshake net/handshake: use sockfd_put() helper 2024-08-27 16:09:25 -07:00
hsr Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-12 17:11:24 -07:00
ieee802154 netdev_features: convert NETIF_F_NETNS_LOCAL to dev->netns_local 2024-09-03 11:36:43 +02:00
ife
ipv4 ipv4: give an IPv4 dev to blackhole_netdev 2024-10-11 15:36:12 -07:00
ipv6 netfilter: fib: check correct rtable in vrf setups 2024-10-09 23:30:31 +02:00
iucv s390/iucv: Fix vargs handling in iucv_alloc_device() 2024-08-22 13:09:20 -07:00
kcm kcm: Serialise kcm_sendmsg() for the same socket. 2024-08-19 18:36:12 -07:00
key
l2tp l2tp: remove unneeded null check in l2tp_v2_session_get_next 2024-09-04 16:39:32 -07:00
l3mdev
lapb
llc llc: Constify struct llc_sap_state_trans 2024-07-15 08:51:19 -07:00
mac80211 move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
mac802154 Including fixes from ieee802154, bluetooth and netfilter. 2024-10-03 09:44:00 -07:00
mctp mctp: Handle error of rtnl_register_module(). 2024-10-10 15:39:35 +02:00
mpls mpls: Handle error of rtnl_register_module(). 2024-10-10 15:39:35 +02:00
mptcp mptcp: prevent MPC handshake on port-based signal endpoints 2024-10-15 10:57:02 -07:00
ncsi net/ncsi: Disable the ncsi work before freeing the associated structure 2024-10-03 10:14:14 +02:00
netfilter netfilter: xtables: avoid NFPROTO_UNSPEC where needed 2024-10-09 23:20:46 +02:00
netlabel netlabel: fix RCU annotation for IPv4 options on socket creation 2024-05-13 14:58:12 -07:00
netlink net: Fix an unsafe loop on the list 2024-10-04 15:37:15 -07:00
netrom net/netrom: prefer strscpy over strcpy 2024-08-29 12:33:07 -07:00
nfc Quite smaller than usual. Notably it includes the fix for the unix 2024-05-23 12:49:37 -07:00
nsh
openvswitch netdev_features: convert NETIF_F_NETNS_LOCAL to dev->netns_local 2024-09-03 11:36:43 +02:00
packet net: add support for skbs with unreadable frags 2024-09-11 20:44:31 -07:00
phonet phonet: Handle error of rtnl_register_module(). 2024-10-10 15:39:36 +02:00
psample net: psample: fix flag being set in wrong skb 2024-07-11 18:11:31 -07:00
qrtr net: qrtr: Update packets cloning when broadcasting 2024-09-24 10:48:16 +02:00
rds net: rds: add option for GCOV profiling 2024-08-09 13:18:46 +01:00
rfkill [tree-wide] finally take no_llseek out 2024-09-27 08:18:43 -07:00
rose net: change proto and proto_ops accept type 2024-05-13 18:19:09 -06:00
rxrpc rxrpc: Fix uninitialised variable in rxrpc_send_data() 2024-10-03 16:23:21 -07:00
sched net/sched: accept TCA_STAB only for root qdisc 2024-10-08 15:38:56 -07:00
sctp sctp: ensure sk_state is set to CLOSED if hashing fails in sctp_listen_start 2024-10-09 13:36:32 +01:00
smc net/smc: Fix searching in list of known pnetids in smc_pnet_add_pnetid 2024-10-15 10:56:31 -07:00
strparser
sunrpc move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
switchdev net: bridge: switchdev: Improve error message for port_obj_add/del functions 2024-05-08 12:19:12 +01:00
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-15 09:13:19 -07:00
tls move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
unix af_unix: Don't return OOB skb in manage_oob(). 2024-09-09 17:14:27 -07:00
vmw_vsock virtio: bugfixes 2024-10-07 11:33:26 -07:00
wireless move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
x25 net: change proto and proto_ops accept type 2024-05-13 18:19:09 -06:00
xdp bpf-next-6.12 2024-09-21 09:27:50 -07:00
xfrm move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
compat.c
devres.c
Kconfig memory-provider: disable building dmabuf mp on !CONFIG_PAGE_POOL 2024-09-13 11:41:45 -07:00
Kconfig.debug
Makefile
socket.c net: explicitly clear the sk pointer, when pf->create fails 2024-10-07 16:21:59 -07:00
sysctl_net.c sysctl: Remove check for sentinel element in ctl_table arrays 2024-06-13 10:50:52 +02:00