tools/testing/selftests/bpf/prog_tests/kernel_flag.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Microsoft */
#include <test_progs.h>
#include "kfunc_call_test.skel.h"
#include "kfunc_call_test.lskel.h"
#include "test_kernel_flag.skel.h"

void test_kernel_flag(void)
{
	struct test_kernel_flag *lsm_skel;
	struct kfunc_call_test *skel = NULL;
	struct kfunc_call_test_lskel *lskel = NULL;
	struct bpf_program *prog;
	__u32 flags;
	int ret;

	lsm_skel = test_kernel_flag__open();
	if (!ASSERT_OK_PTR(lsm_skel, "lsm_skel"))
		return;

	prog = lsm_skel->progs.bpf;
	flags = bpf_program__flags(prog);
	ASSERT_EQ(flags & BPF_F_SLEEPABLE,
		  BPF_F_SLEEPABLE, "sleepable in program flags");

	ret = bpf_program__add_flags(prog, BPF_F_ANY_ALIGNMENT);
	ASSERT_OK(ret, "bpf_program__add_flags ret");
	ASSERT_EQ(bpf_program__flags(prog), flags | BPF_F_ANY_ALIGNMENT,
		  "bpf_program__add_flags value");

	ret = bpf_program__clear_flags(prog, BPF_F_ANY_ALIGNMENT);
	ASSERT_OK(ret, "bpf_program__clear_flags ret");
	ASSERT_EQ(bpf_program__flags(prog), flags, "bpf_program__clear_flags value");

	ret = test_kernel_flag__load(lsm_skel);
	if (!ASSERT_OK(ret, "test_kernel_flag__load"))
		goto close_prog;

	lsm_skel->bss->monitored_tid = sys_gettid();

	ret = test_kernel_flag__attach(lsm_skel);
	if (!ASSERT_OK(ret, "test_kernel_flag__attach"))
		goto close_prog;

	/* Test with skel. This should pass the gatekeeper */
	skel = kfunc_call_test__open_and_load();
	if (!ASSERT_OK_PTR(skel, "skel"))
		goto close_prog;

	/* Test with lskel. This should fail due to blocking kernel-based bpf() invocations */
	lskel = kfunc_call_test_lskel__open_and_load();
	if (!ASSERT_ERR_PTR(lskel, "lskel"))
		goto close_prog;

close_prog:
	if (skel)
		kfunc_call_test__destroy(skel);
	if (lskel)
		kfunc_call_test_lskel__destroy(lskel);

	lsm_skel->bss->monitored_tid = 0;
	test_kernel_flag__destroy(lsm_skel);
}