linux/net
Kuniyuki Iwashima 51e394c6f8 netrom: Fix use-after-free of a listening socket.
[ Upstream commit 409db27e3a ]

syzbot reported a use-after-free in do_accept(), precisely nr_accept()
as sk_prot_alloc() allocated the memory and sock_put() frees it. [0]

The issue could happen if the heartbeat timer is fired and
nr_heartbeat_expiry() calls nr_destroy_socket(), where a socket
has SOCK_DESTROY or a listening socket has SOCK_DEAD.

In this case, the first condition cannot be true.  SOCK_DESTROY is
flagged in nr_release() only when the file descriptor is close()d,
but accept() is being called for the listening socket, so the second
condition must be true.

Usually, the AF_NETROM listener neither starts timers nor sets
SOCK_DEAD.  However, the condition is met if connect() fails before
listen().  connect() starts the t1 timer and heartbeat timer, and
t1timer calls nr_disconnect() when timeout happens.  Then, SOCK_DEAD
is set, and if we call listen(), the heartbeat timer calls
nr_destroy_socket().

  nr_connect
    nr_establish_data_link(sk)
      nr_start_t1timer(sk)
    nr_start_heartbeat(sk)
                                    nr_t1timer_expiry
                                      nr_disconnect(sk, ETIMEDOUT)
                                        nr_sk(sk)->state = NR_STATE_0
                                        sk->sk_state = TCP_CLOSE
                                        sock_set_flag(sk, SOCK_DEAD)
nr_listen
  if (sk->sk_state != TCP_LISTEN)
    sk->sk_state = TCP_LISTEN
                                    nr_heartbeat_expiry
                                      switch (nr->state)
                                      case NR_STATE_0
                                        if (sk->sk_state == TCP_LISTEN &&
                                            sock_flag(sk, SOCK_DEAD))
                                          nr_destroy_socket(sk)

This path seems expected, and nr_destroy_socket() is called to clean
up resources.  Initially, there was sock_hold() before nr_destroy_socket()
so that the socket would not be freed, but the commit 517a16b1a8
("netrom: Decrease sock refcount when sock timers expire") accidentally
removed it.

To fix use-after-free, let's add sock_hold().

[0]:
BUG: KASAN: use-after-free in do_accept+0x483/0x510 net/socket.c:1848
Read of size 8 at addr ffff88807978d398 by task syz-executor.3/5315

CPU: 0 PID: 5315 Comm: syz-executor.3 Not tainted 6.2.0-rc3-syzkaller-00165-gd9fc1511728c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:306 [inline]
 print_report+0x15e/0x461 mm/kasan/report.c:417
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:517
 do_accept+0x483/0x510 net/socket.c:1848
 __sys_accept4_file net/socket.c:1897 [inline]
 __sys_accept4+0x9a/0x120 net/socket.c:1927
 __do_sys_accept net/socket.c:1944 [inline]
 __se_sys_accept net/socket.c:1941 [inline]
 __x64_sys_accept+0x75/0xb0 net/socket.c:1941
 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: 0033:0x7fa436a8c0c9
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:00007fa437784168 EFLAGS: 00000246 ORIG_RAX: 000000000000002b
RAX: ffffffffffffffda RBX: 00007fa436bac050 RCX: 00007fa436a8c0c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007fa436ae7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffebc6700df R14: 00007fa437784300 R15: 0000000000022000
 </TASK>

Allocated by task 5294:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:371 [inline]
 ____kasan_kmalloc mm/kasan/common.c:330 [inline]
 __kasan_kmalloc+0xa3/0xb0 mm/kasan/common.c:380
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:968 [inline]
 __kmalloc+0x5a/0xd0 mm/slab_common.c:981
 kmalloc include/linux/slab.h:584 [inline]
 sk_prot_alloc+0x140/0x290 net/core/sock.c:2038
 sk_alloc+0x3a/0x7a0 net/core/sock.c:2091
 nr_create+0xb6/0x5f0 net/netrom/af_netrom.c:433
 __sock_create+0x359/0x790 net/socket.c:1515
 sock_create net/socket.c:1566 [inline]
 __sys_socket_create net/socket.c:1603 [inline]
 __sys_socket_create net/socket.c:1588 [inline]
 __sys_socket+0x133/0x250 net/socket.c:1636
 __do_sys_socket net/socket.c:1649 [inline]
 __se_sys_socket net/socket.c:1647 [inline]
 __x64_sys_socket+0x73/0xb0 net/socket.c:1647
 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

Freed by task 14:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:518
 ____kasan_slab_free mm/kasan/common.c:236 [inline]
 ____kasan_slab_free+0x13b/0x1a0 mm/kasan/common.c:200
 kasan_slab_free include/linux/kasan.h:177 [inline]
 __cache_free mm/slab.c:3394 [inline]
 __do_kmem_cache_free mm/slab.c:3580 [inline]
 __kmem_cache_free+0xcd/0x3b0 mm/slab.c:3587
 sk_prot_free net/core/sock.c:2074 [inline]
 __sk_destruct+0x5df/0x750 net/core/sock.c:2166
 sk_destruct net/core/sock.c:2181 [inline]
 __sk_free+0x175/0x460 net/core/sock.c:2192
 sk_free+0x7c/0xa0 net/core/sock.c:2203
 sock_put include/net/sock.h:1991 [inline]
 nr_heartbeat_expiry+0x1d7/0x460 net/netrom/nr_timer.c:148
 call_timer_fn+0x1da/0x7c0 kernel/time/timer.c:1700
 expire_timers+0x2c6/0x5c0 kernel/time/timer.c:1751
 __run_timers kernel/time/timer.c:2022 [inline]
 __run_timers kernel/time/timer.c:1995 [inline]
 run_timer_softirq+0x326/0x910 kernel/time/timer.c:2035
 __do_softirq+0x1fb/0xadc kernel/softirq.c:571

Fixes: 517a16b1a8 ("netrom: Decrease sock refcount when sock timers expire")
Reported-by: syzbot+5fafd5cfe1fc91f6b352@syzkaller.appspotmail.com
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230120231927.51711-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:45 +01:00
..
6lowpan
9p 9p/client: fix data race on req->status 2023-01-12 12:02:36 +01:00
802 mrp: introduce active flags to prevent UAF when applicant uninit 2022-12-31 13:33:02 +01:00
8021q net: gro: skb_gro_header helper function 2022-08-25 10:33:21 +02:00
appletalk
atm net/atm: fix proc_mpc_write incorrect return value 2022-10-15 11:08:36 +01:00
ax25 ax25: move from strlcpy with unused retval to strscpy 2022-08-22 17:55:50 -07:00
batman-adv Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-09-22 13:02:10 -07:00
bluetooth Bluetooth: hci_sync: cancel cmd_timer if hci_open failed 2023-02-01 08:34:35 +01:00
bpf bpf: Move skb->len == 0 checks into __bpf_redirect 2022-12-31 13:32:14 +01:00
bpfilter
bridge bridge: switchdev: Fix memory leaks when changing VLAN protocol 2022-11-15 13:38:11 +01:00
caif caif: fix memory leak in cfctrl_linkup_request() 2023-01-12 12:02:33 +01:00
can can: af_can: fix NULL pointer dereference in can_rcv_filter 2022-12-07 10:30:47 +01:00
ceph Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
core net: fix UaF in netns ops registration error path 2023-02-01 08:34:43 +01:00
dcb
dccp dccp/tcp: Fixup bhash2 bucket when connect() fails. 2022-11-22 20:15:37 -08:00
dns_resolver
dsa net: dsa: tag_8021q: avoid leaking ctx on dsa_tag_8021q_register() error path 2022-12-31 13:32:29 +01:00
ethernet net: gro: skb_gro_header helper function 2022-08-25 10:33:21 +02:00
ethtool net/ethtool/ioctl: return -EOPNOTSUPP if we have no phy stats 2023-01-24 07:24:31 +01:00
hsr hsr: Synchronize sequence number updates. 2022-12-31 13:32:22 +01:00
ieee802154 net: ieee802154: fix error return code in dgram_bind() 2022-10-07 09:29:17 +02:00
ife
ipv4 ipv4: prevent potential spectre v1 gadget in fib_metrics_match() 2023-02-01 08:34:45 +01:00
ipv6 ipv6: fix reachability confirmation with proxy_ndp 2023-02-01 08:34:39 +01:00
iucv
kcm kcm: close race conditions on sk_receive_queue 2022-11-15 12:42:26 +01:00
key xfrm: Fix oops in __xfrm_state_delete() 2022-11-22 07:14:55 +01:00
l2tp l2tp: prevent lockdep issue in l2tp_tunnel_register() 2023-02-01 08:34:24 +01:00
l3mdev
lapb
llc
mac80211 wifi: mac80211: Fix iTXQ AMPDU fragmentation handling 2023-02-01 08:34:36 +01:00
mac802154 mac802154: fix missing INIT_LIST_HEAD in ieee802154_if_add() 2022-12-05 09:53:08 +01:00
mctp mctp: Remove device type check at unregister 2022-12-31 13:32:56 +01:00
mpls net: Use u64_stats_fetch_begin_irq() for stats fetch. 2022-08-29 13:02:27 +01:00
mptcp mptcp: netlink: respect v4/v6-only sockets 2023-01-24 07:24:37 +01:00
ncsi genetlink: start to validate reserved header bytes 2022-08-29 12:47:15 +01:00
netfilter netfilter: conntrack: fix vtag checks for ABORT/SHUTDOWN_COMPLETE 2023-02-01 08:34:45 +01:00
netlabel genetlink: start to validate reserved header bytes 2022-08-29 12:47:15 +01:00
netlink netlink: annotate data races around sk_state 2023-02-01 08:34:45 +01:00
netrom netrom: Fix use-after-free of a listening socket. 2023-02-01 08:34:45 +01:00
nfc net: nfc: Fix use-after-free in local_cleanup() 2023-02-01 08:34:17 +01:00
nsh
openvswitch openvswitch: Use kmalloc_size_roundup() to match ksize() usage 2022-12-31 13:32:59 +01:00
packet packet: do not set TP_STATUS_CSUM_VALID on CHECKSUM_COMPLETE 2022-11-29 08:30:18 -08:00
phonet
psample genetlink: start to validate reserved header bytes 2022-08-29 12:47:15 +01:00
qrtr net: qrtr: start MHI channel after endpoit creation 2022-08-15 11:21:42 +01:00
rds treewide: use get_random_{u8,u16}() when possible, part 2 2022-10-11 17:42:58 -06:00
rfkill
rose rose: Fix NULL pointer dereference in rose_send_frame() 2022-11-02 11:57:30 +00:00
rxrpc rxrpc: Fix missing unlock in rxrpc_do_sendmsg() 2022-12-31 13:32:55 +01:00
sched net: sched: gred: prevent races when adding offloads to stats 2023-02-01 08:34:25 +01:00
sctp sctp: sysctl: make extra pointers netns aware 2022-12-31 13:32:28 +01:00
smc net/smc: Fix possible leaked pernet namespace in smc_init() 2022-11-02 20:42:09 -07:00
strparser
sunrpc Revert "SUNRPC: Use RMW bitops in single-threaded hot paths" 2023-01-14 10:33:42 +01:00
switchdev
tipc tipc: fix unexpected link reset due to discovery messages 2023-01-18 11:58:24 +01:00
tls bpf, sockmap: Fix missing BPF_F_INGRESS flag when using apply_bytes 2022-12-31 13:32:20 +01:00
unix unix: Fix race in SOCK_SEQPACKET's unix_dgram_sendmsg() 2022-12-31 13:32:54 +01:00
vmw_vsock net: vmw_vsock: vmci: Check memcpy_from_msg() 2022-12-31 13:32:26 +01:00
wireless wifi: cfg80211: Fix not unregister reg_pdev when load_builtin_regdb_keys() fails 2022-12-31 13:32:20 +01:00
x25 net/x25: Fix skb leak in x25_lapb_receive_frame() 2022-11-15 20:22:19 -08:00
xdp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-10-03 17:44:18 -07:00
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec 2022-11-23 19:18:59 -08:00
compat.c net: clear msg_get_inq in __get_compat_msghdr() 2022-09-20 08:23:20 -07:00
devres.c
Kconfig Remove DECnet support from kernel 2022-08-22 14:26:30 +01:00
Kconfig.debug net: make NET_(DEV|NS)_REFCNT_TRACKER depend on NET 2022-09-20 14:23:56 -07:00
Makefile Remove DECnet support from kernel 2022-08-22 14:26:30 +01:00
socket.c d_path pile 2022-10-06 16:55:41 -07:00
sysctl_net.c