bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 69 insertions, 0 deletions

diff --git a/net/rxrpc/call_state.c b/net/rxrpc/call_state.c
new file mode 100644
index 000000000..6afb54373
--- /dev/null
+++ b/net/rxrpc/call_state.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Call state changing functions.
+ *
+ * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include "ar-internal.h"
+
+/*
+ * Transition a call to the complete state.
+ */
+bool rxrpc_set_call_completion(struct rxrpc_call *call,
+				 enum rxrpc_call_completion compl,
+				 u32 abort_code,
+				 int error)
+{
+	if (__rxrpc_call_state(call) == RXRPC_CALL_COMPLETE)
+		return false;
+
+	call->abort_code = abort_code;
+	call->error = error;
+	call->completion = compl;
+	/* Allow reader of completion state to operate locklessly */
+	rxrpc_set_call_state(call, RXRPC_CALL_COMPLETE);
+	trace_rxrpc_call_complete(call);
+	wake_up(&call->waitq);
+	rxrpc_notify_socket(call);
+	return true;
+}
+
+/*
+ * Record that a call successfully completed.
+ */
+bool rxrpc_call_completed(struct rxrpc_call *call)
+{
+	return rxrpc_set_call_completion(call, RXRPC_CALL_SUCCEEDED, 0, 0);
+}
+
+/*
+ * Record that a call is locally aborted.
+ */
+bool rxrpc_abort_call(struct rxrpc_call *call, rxrpc_seq_t seq,
+		      u32 abort_code, int error, enum rxrpc_abort_reason why)
+{
+	trace_rxrpc_abort(call->debug_id, why, call->cid, call->call_id, seq,
+			  abort_code, error);
+	if (!rxrpc_set_call_completion(call, RXRPC_CALL_LOCALLY_ABORTED,
+				       abort_code, error))
+		return false;
+	if (test_bit(RXRPC_CALL_EXPOSED, &call->flags))
+		rxrpc_send_abort_packet(call);
+	return true;
+}
+
+/*
+ * Record that a call errored out before even getting off the ground, thereby
+ * setting the state to allow it to be destroyed.
+ */
+void rxrpc_prefail_call(struct rxrpc_call *call, enum rxrpc_call_completion compl,
+			int error)
+{
+	call->abort_code	= RX_CALL_DEAD;
+	call->error		= error;
+	call->completion	= compl;
+	call->_state		= RXRPC_CALL_COMPLETE;
+	trace_rxrpc_call_complete(call);
+	WARN_ON_ONCE(__test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags));
+}