CVE-2024-56694

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

bpf: fix recursive lock when verdict program return SK_PASS

When the stream_verdict program returns SK_PASS, it places the received skb

into its own receive queue, but a recursive lock eventually occurs, leading

to an operating system deadlock. This issue has been present since v6.9.

'''

sk_psock_strp_data_ready

write_lock_bh(&sk->sk_callback_lock)

strp_data_ready

strp_read_sock

read_sock -> tcp_read_sock

strp_recv

cb.rcv_msg -> sk_psock_strp_read

# now stream_verdict return SK_PASS without peer sock assign

__SK_PASS = sk_psock_map_verd(SK_PASS, NULL)

sk_psock_verdict_apply

sk_psock_skb_ingress_self

sk_psock_skb_ingress_enqueue

sk_psock_data_ready

read_lock_bh(&sk->sk_callback_lock) <= dead lock

'''

This topic has been discussed before, but it has not bee

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References