From: Xingwang Xiang Date: Sun, 17 May 2026 14:56:26 +0000 (+0900) Subject: bpf, skmsg: fix verdict sk_data_ready racing with ktls rx X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ddf8029623a1af20e984c040e89ff918158397ab;p=thirdparty%2Fkernel%2Flinux.git bpf, skmsg: fix verdict sk_data_ready racing with ktls rx sk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and defers to psock->saved_data_ready when a TLS RX context is present, avoiding a conflict with the TLS strparser's ownership of the receive queue (commit e91de6afa81c, "bpf: Fix running sk_skb program types with ktls"). sk_psock_verdict_data_ready() has no equivalent guard. When a socket is inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is configured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready as rx_ctx->saved_data_ready. On data arrival: tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready -> saved_data_ready() = sk_psock_verdict_data_ready() -> tcp_read_skb() drains sk_receive_queue via __skb_unlink() without calling tcp_eat_skb(), so copied_seq is not advanced. tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls tcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and returns with rx_ctx->strp.anchor.frag_list pointing at a psock-owned (potentially freed) skb. tls_decrypt_sg() subsequently walks that frag_list: use-after-free. Apply the same fix as sk_psock_strp_data_ready(): if a TLS RX context is present, call psock->saved_data_ready (sock_def_readable) to wake recv() waiters and return immediately, leaving the receive queue untouched. TLS retains sole ownership of the queue and decrypts the record normally through tls_sw_recvmsg(). Fixes: ef5659280eb1 ("bpf, sockmap: Allow skipping sk_skb parser program") Signed-off-by: Xingwang Xiang Link: https://patch.msgid.link/20260517145630.20521-2-v3rdant.xiang@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/net/core/skmsg.c b/net/core/skmsg.c index 6187a83bd741..e1850caf1a71 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -1268,12 +1268,19 @@ out: static void sk_psock_verdict_data_ready(struct sock *sk) { const struct proto_ops *ops = NULL; + struct sk_psock *psock; struct socket *sock; int copied; trace_sk_data_ready(sk); rcu_read_lock(); + psock = sk_psock(sk); + if (psock && tls_sw_has_ctx_rx(sk)) { + psock->saved_data_ready(sk); + rcu_read_unlock(); + return; + } sock = READ_ONCE(sk->sk_socket); if (likely(sock)) ops = READ_ONCE(sock->ops); @@ -1283,8 +1290,6 @@ static void sk_psock_verdict_data_ready(struct sock *sk) copied = ops->read_skb(sk, sk_psock_verdict_recv); if (copied >= 0) { - struct sk_psock *psock; - rcu_read_lock(); psock = sk_psock(sk); if (psock)