CVE-2022-49207 in Linux
Summary
by MITRE • 02/26/2025
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: 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
WARNING: CPU: 0 PID: 531 at net/ipv4/af_inet.c:154 inet_sock_destruct+0x175/0x1b0 Call Trace: __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
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Analysis
by VulDB Data Team • 10/25/2025
The vulnerability identified as CVE-2022-49207 resides within the Linux kernel's implementation of Berkeley Packet Filter (BPF) and socket map functionalities, specifically concerning the handling of socket message queuing during connection teardown operations. This memory leak occurs when the tcp_bpf_sendmsg function executes concurrently with sock_map_close, creating a race condition where data may be enqueued onto an ingress message queue while the system attempts to free associated memory structures. The flaw manifests in the sk_psock_queue_msg function which processes messages during BPF ingress operations, leading to improper memory accounting and release. The technical root cause stems from a lack of proper synchronization between the message queuing process and the socket destruction sequence, where sk_mem_charge allocates memory that is not correctly freed due to the overlapping operations. This memory leak directly impacts system stability and resource utilization, particularly in environments where BPF socket redirection is actively employed, such as in network traffic control, security policy enforcement, or load balancing scenarios. The vulnerability is classified under CWE-401: Improper Release of Memory and aligns with ATT&CK technique T1059.003: Command and Scripting Interpreter: Windows Command Shell, though adapted for kernel-level memory management issues.
The operational impact of this vulnerability extends beyond simple memory consumption, potentially leading to system instability, performance degradation, and eventual resource exhaustion. When the race condition occurs, the kernel's memory management subsystem becomes corrupted as messages are charged to socket memory accounting but never properly released through the sk_msg_free() function before the sk_psock_destroy() process begins. The call trace reveals a complex interaction involving inet_csk_destroy_sock, tcp_rcv_state_process, and various socket destruction handlers, indicating that the issue propagates through multiple layers of the network stack. The warning messages displayed by the kernel demonstrate the failure points where sk_stream_kill_queues and inet_sock_destruct encounter memory inconsistencies during the teardown process. This type of memory leak can be particularly insidious because it occurs in kernel space and may not immediately manifest as a system crash, instead gradually depleting available memory resources. The vulnerability is particularly concerning in high-throughput network environments where BPF socket redirection is frequently used, as the accumulation of leaked memory can lead to system instability or denial of service conditions.
Mitigation strategies for CVE-2022-49207 must address both the immediate kernel patch and broader system hardening measures. The primary fix involves implementing proper synchronization mechanisms within the BPF socket map subsystem to prevent concurrent access between tcp_bpf_sendmsg and sock_map_close operations during the message queuing and destruction phases. This includes ensuring that sk_psock_queue_msg properly handles memory accounting before allowing socket teardown operations to proceed, potentially through additional locking mechanisms or state checks that prevent the race condition from occurring. System administrators should prioritize applying the official kernel patch that resolves this memory leak by ensuring that sk_msg_free() is called before memory release operations, thereby properly accounting for charged memory and associated scatter-gather pages. Additionally, monitoring for kernel warning messages related to socket destruction and memory management should be implemented to detect potential exploitation attempts or system instability. Organizations should consider implementing network traffic monitoring to identify unusual patterns that may indicate BPF socket map usage that could trigger this vulnerability, particularly in environments where BPF programs are actively deployed for traffic control or security enforcement. The mitigation approach aligns with security best practices outlined in the NIST Cybersecurity Framework and should be integrated into broader vulnerability management processes to prevent similar issues in other kernel subsystems.