diff --git a/bpf_progs/netd.c b/bpf_progs/netd.c index 1c84d63479..c4b27b8200 100644 --- a/bpf_progs/netd.c +++ b/bpf_progs/netd.c @@ -626,12 +626,13 @@ DEFINE_XTBPF_PROG("skfilter/allowlist/xtbpf", AID_ROOT, AID_NET_ADMIN, xt_bpf_al uint32_t sock_uid = bpf_get_socket_uid(skb); if (is_system_uid(sock_uid)) return BPF_MATCH; - // 65534 is the overflow 'nobody' uid, usually this being returned means - // that skb->sk is NULL during RX (early decap socket lookup failure), - // which commonly happens for incoming packets to an unconnected udp socket. - // Additionally bpf_get_socket_cookie() returns 0 if skb->sk is NULL - if ((sock_uid == 65534) && !bpf_get_socket_cookie(skb) && is_received_skb(skb)) - return BPF_MATCH; + // kernel's DEFAULT_OVERFLOWUID is 65534, this is the overflow 'nobody' uid, + // usually this being returned means that skb->sk is NULL during RX + // (early decap socket lookup failure), which commonly happens for incoming + // packets to an unconnected udp socket. + // But it can also happen for egress from a timewait socket. + // Let's treat such cases as 'root' which is_system_uid() + if (sock_uid == 65534) return BPF_MATCH; UidOwnerValue* allowlistMatch = bpf_uid_owner_map_lookup_elem(&sock_uid); if (allowlistMatch) return allowlistMatch->rule & HAPPY_BOX_MATCH ? BPF_MATCH : BPF_NOMATCH;