CVE-2022-49207

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

Weakness

The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/03948ed6553960db62f1c33bec29e64d7c191a3f
• https://git.kernel.org/stable/c/4dd2e947d3be13a4de3b3028859b9a6497266bcf
• https://git.kernel.org/stable/c/938d3480b92fa5e454b7734294f12a7b75126f09
• https://git.kernel.org/stable/c/ef9785f429794567792561a584901faa9291d3ee