selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/include/net/handshake.h b/include/net/handshake.h
new file mode 100644
index 000000000..8ebd4f9ed
--- /dev/null
+++ b/include/net/handshake.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Generic netlink HANDSHAKE service.
+ *
+ * Author: Chuck Lever <chuck.lever@oracle.com>
+ *
+ * Copyright (c) 2023, Oracle and/or its affiliates.
+ */
+
+#ifndef _NET_HANDSHAKE_H
+#define _NET_HANDSHAKE_H
+
+enum {
+	TLS_NO_KEYRING = 0,
+	TLS_NO_PEERID = 0,
+	TLS_NO_CERT = 0,
+	TLS_NO_PRIVKEY = 0,
+};
+
+typedef void	(*tls_done_func_t)(void *data, int status,
+				   key_serial_t peerid);
+
+struct tls_handshake_args {
+	struct socket		*ta_sock;
+	tls_done_func_t		ta_done;
+	void			*ta_data;
+	const char		*ta_peername;
+	unsigned int		ta_timeout_ms;
+	key_serial_t		ta_keyring;
+	key_serial_t		ta_my_cert;
+	key_serial_t		ta_my_privkey;
+	unsigned int		ta_num_peerids;
+	key_serial_t		ta_my_peerids[5];
+};
+
+int tls_client_hello_anon(const struct tls_handshake_args *args, gfp_t flags);
+int tls_client_hello_x509(const struct tls_handshake_args *args, gfp_t flags);
+int tls_client_hello_psk(const struct tls_handshake_args *args, gfp_t flags);
+int tls_server_hello_x509(const struct tls_handshake_args *args, gfp_t flags);
+int tls_server_hello_psk(const struct tls_handshake_args *args, gfp_t flags);
+
+bool tls_handshake_cancel(struct sock *sk);
+void tls_handshake_close(struct socket *sock);
+
+u8 tls_get_record_type(const struct sock *sk, const struct cmsghdr *msg);
+void tls_alert_recv(const struct sock *sk, const struct msghdr *msg,
+		    u8 *level, u8 *description);
+
+#endif /* _NET_HANDSHAKE_H */