[PATCH 5.17 0660/1126] bpf, sockmap: Fix memleak in sk_psock_queue_msg

Greg Kroah-Hartman
2022-04-05T08:37:14Z

From: Wang Yufen <wangyufen@huawei.com>

[ Upstream commit 938d3480b92fa5e454b7734294f12a7b75126f09 ]

If tcp_bpf_sendmsg is running during a tear down operation we may enqueue
data on the ingress msg queue while tear down is trying to free it.

sk1 (redirect sk2) sk2
------------------- ---------------
tcp_bpf_sendmsg()
tcp_bpf_send_verdict()
tcp_bpf_sendmsg_redir()
bpf_tcp_ingress()
sock_map_close()
lock_sock()
lock_sock() ... blocking
sk_psock_stop
sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
release_sock(sk);
lock_sock()
sk_mem_charge()
get_page()
sk_psock_queue_msg()
sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED);
drop_sk_msg()
release_sock()

While drop_sk_msg(), the msg has charged memory form sk by sk_mem_charge
and has sg pages need to put. To fix we use sk_msg_free() and then kfee()
msg.

This issue can cause the following info:
WARNING: CPU: 0 PID: 9202 at net/core/stream.c:205 sk_stream_kill_queues+0xc8/0xe0
Call Trace:
<IRQ>
inet_csk_destroy_sock+0x55/0x110
tcp_rcv_state_process+0xe5f/0xe90
? sk_filter_trim_cap+0x10d/0x230
? tcp_v4_do_rcv+0x161/0x250
tcp_v4_do_rcv+0x161/0x250
tcp_v4_rcv+0xc3a/0xce0
ip_protocol_deliver_rcu+0x3d/0x230
ip_local_deliver_finish+0x54/0x60
ip_local_deliver+0xfd/0x110
? ip_protocol_deliver_rcu+0x230/0x230
ip_rcv+0xd6/0x100
? ip_local_deliver+0x110/0x110
__netif_receive_skb_one_core+0x85/0xa0
process_backlog+0xa4/0x160
__napi_poll+0x29/0x1b0
net_rx_action+0x287/0x300
__do_softirq+0xff/0x2fc
do_softirq+0x79/0x90
</IRQ>

WARNING: CPU: 0 PID: 531 at net/ipv4/af_inet.c:154 inet_sock_destruct+0x175/0x1b0
Call Trace:
<TASK>
__sk_destruct+0x24/0x1f0
sk_psock_destroy+0x19b/0x1c0
process_one_work+0x1b3/0x3c0
? process_one_work+0x3c0/0x3c0
worker_thread+0x30/0x350
? process_one_work+0x3c0/0x3c0
kthread+0xe6/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
</TASK>

Fixes: 9635720b7c88 ("bpf, sockmap: Fix memleak on ingress msg enqueue")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220304081145.2037182-2-wangyufen@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/skmsg.h | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 18a717fe62eb..7f32dd59e751 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -310,21 +310,16 @@ static inline void sock_drop(struct sock *sk, struct sk_buff *skb)
kfree_skb(skb);
}

-static inline void drop_sk_msg(struct sk_psock *psock, struct sk_msg *msg)
-{
- if (msg->skb)
- sock_drop(psock->sk, msg->skb);
- kfree(msg);
-}
-
static inline void sk_psock_queue_msg(struct sk_psock *psock,
struct sk_msg *msg)
{
spin_lock_bh(&psock->ingress_lock);
if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
list_add_tail(&msg->list, &psock->ingress_msg);
- else
- drop_sk_msg(psock, msg);
+ else {
+ sk_msg_free(psock->sk, msg);
+ kfree(msg);
+ }
spin_unlock_bh(&psock->ingress_lock);
}

--
2.34.1