bpf: avoid misuse of psock when TCP_ULP_BPF collides with another ULP
Currently we check sk_user_data is non NULL to determine if the sk exists in a map. However, this is not sufficient to ensure the psock or the ULP ops are not in use by another user, such as kcm or TLS. To avoid this when adding a sock to a map also verify it is of the correct ULP type. Additionally, when releasing a psock verify that it is the TCP_ULP_BPF type before releasing the ULP. The error case where we abort an update due to ULP collision can cause this error path. For example, __sock_map_ctx_update_elem() [...] err = tcp_set_ulp_id(sock, TCP_ULP_BPF) <- collides with TLS if (err) <- so err out here goto out_free [...] out_free: smap_release_sock() <- calling tcp_cleanup_ulp releases the TLS ULP incorrectly. Fixes: 2f857d04 ("bpf: sockmap, remove STRPARSER map_flags and add multi-map support") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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