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| author | Liu Jian <liujian56@huawei.com> | 2022-08-23 21:37:54 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-26 13:19:38 +0200 |
| commit | 5fe03917bb017d9af68a95f989f1c122eebc69a6 (patch) | |
| tree | 322f8a2c3e3408b59a655a730782128c257d0abd /net | |
| parent | 384b5a396bb63811f654d28e20dc58729754810f (diff) | |
| download | linux-stable-5fe03917bb017d9af68a95f989f1c122eebc69a6.tar.gz linux-stable-5fe03917bb017d9af68a95f989f1c122eebc69a6.tar.bz2 linux-stable-5fe03917bb017d9af68a95f989f1c122eebc69a6.zip | |
net: If sock is dead don't access sock's sk_wq in sk_stream_wait_memory
[ Upstream commit 3f8ef65af927db247418d4e1db49164d7a158fc5 ]
Fixes the below NULL pointer dereference:
[...]
[ 14.471200] Call Trace:
[ 14.471562] <TASK>
[ 14.471882] lock_acquire+0x245/0x2e0
[ 14.472416] ? remove_wait_queue+0x12/0x50
[ 14.473014] ? _raw_spin_lock_irqsave+0x17/0x50
[ 14.473681] _raw_spin_lock_irqsave+0x3d/0x50
[ 14.474318] ? remove_wait_queue+0x12/0x50
[ 14.474907] remove_wait_queue+0x12/0x50
[ 14.475480] sk_stream_wait_memory+0x20d/0x340
[ 14.476127] ? do_wait_intr_irq+0x80/0x80
[ 14.476704] do_tcp_sendpages+0x287/0x600
[ 14.477283] tcp_bpf_push+0xab/0x260
[ 14.477817] tcp_bpf_sendmsg_redir+0x297/0x500
[ 14.478461] ? __local_bh_enable_ip+0x77/0xe0
[ 14.479096] tcp_bpf_send_verdict+0x105/0x470
[ 14.479729] tcp_bpf_sendmsg+0x318/0x4f0
[ 14.480311] sock_sendmsg+0x2d/0x40
[ 14.480822] ____sys_sendmsg+0x1b4/0x1c0
[ 14.481390] ? copy_msghdr_from_user+0x62/0x80
[ 14.482048] ___sys_sendmsg+0x78/0xb0
[ 14.482580] ? vmf_insert_pfn_prot+0x91/0x150
[ 14.483215] ? __do_fault+0x2a/0x1a0
[ 14.483738] ? do_fault+0x15e/0x5d0
[ 14.484246] ? __handle_mm_fault+0x56b/0x1040
[ 14.484874] ? lock_is_held_type+0xdf/0x130
[ 14.485474] ? find_held_lock+0x2d/0x90
[ 14.486046] ? __sys_sendmsg+0x41/0x70
[ 14.486587] __sys_sendmsg+0x41/0x70
[ 14.487105] ? intel_pmu_drain_pebs_core+0x350/0x350
[ 14.487822] do_syscall_64+0x34/0x80
[ 14.488345] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[...]
The test scenario has the following flow:
thread1 thread2
----------- ---------------
tcp_bpf_sendmsg
tcp_bpf_send_verdict
tcp_bpf_sendmsg_redir sock_close
tcp_bpf_push_locked __sock_release
tcp_bpf_push //inet_release
do_tcp_sendpages sock->ops->release
sk_stream_wait_memory // tcp_close
sk_wait_event sk->sk_prot->close
release_sock(__sk);
***
lock_sock(sk);
__tcp_close
sock_orphan(sk)
sk->sk_wq = NULL
release_sock
****
lock_sock(__sk);
remove_wait_queue(sk_sleep(sk), &wait);
sk_sleep(sk)
//NULL pointer dereference
&rcu_dereference_raw(sk->sk_wq)->wait
While waiting for memory in thread1, the socket is released with its wait
queue because thread2 has closed it. This caused by tcp_bpf_send_verdict
didn't increase the f_count of psock->sk_redir->sk_socket->file in thread1.
We should check if SOCK_DEAD flag is set on wakeup in sk_stream_wait_memory
before accessing the wait queue.
Suggested-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20220823133755.314697-2-liujian56@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/stream.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/stream.c b/net/core/stream.c index 3d98774cf128..7b411a91a81c 100644 --- a/net/core/stream.c +++ b/net/core/stream.c @@ -159,7 +159,8 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p) *timeo_p = current_timeo; } out: - remove_wait_queue(sk_sleep(sk), &wait); + if (!sock_flag(sk, SOCK_DEAD)) + remove_wait_queue(sk_sleep(sk), &wait); return err; do_error: |