Medium · published February 26, 2025
In the Linux kernel, the following vulnerability has been resolved:
bpf, sockmap: Fix memleak in sk_psock_queue_msg
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>