Commit 9d66d60e authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Martin KaFai Lau
Browse files

selftests/bpf: add another struct_ops callback use case test 



Add a test which tests the case that was just fixed. Kernel has full
type information about callback, but user explicitly nulls out the
reference to declaratively set BPF program reference.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-4-andrii@kernel.org


Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parent e18e2e70

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

+27 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
#include <time.h>



#include "struct_ops_module.skel.h"

#include "struct_ops_nulled_out_cb.skel.h"



static void check_map_info(struct bpf_map_info *info)

{
@@ -174,6 +175,30 @@ static void test_struct_ops_incompatible(void) 
	struct_ops_module__destroy(skel);

}



/* validate that it's ok to "turn off" callback that kernel supports */

static void test_struct_ops_nulled_out_cb(void)

{

	struct struct_ops_nulled_out_cb *skel;

	int err;



	skel = struct_ops_nulled_out_cb__open();

	if (!ASSERT_OK_PTR(skel, "skel_open"))

		return;



	/* kernel knows about test_1, but we still null it out */

	skel->struct_ops.ops->test_1 = NULL;



	err = struct_ops_nulled_out_cb__load(skel);

	if (!ASSERT_OK(err, "skel_load"))

		goto cleanup;



	ASSERT_FALSE(bpf_program__autoload(skel->progs.test_1_turn_off), "prog_autoload");

	ASSERT_LT(bpf_program__fd(skel->progs.test_1_turn_off), 0, "prog_fd");



cleanup:

	struct_ops_nulled_out_cb__destroy(skel);

}



void serial_test_struct_ops_module(void)

{

	if (test__start_subtest("test_struct_ops_load"))
@@ -182,5 +207,7 @@ void serial_test_struct_ops_module(void) 
		test_struct_ops_not_zeroed();

	if (test__start_subtest("test_struct_ops_incompatible"))

		test_struct_ops_incompatible();

	if (test__start_subtest("test_struct_ops_null_out_cb"))

		test_struct_ops_nulled_out_cb();

}

tools/testing/selftests/bpf/progs/struct_ops_nulled_out_cb.c

0 → 100644
+22 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */

#include <vmlinux.h>

#include <bpf/bpf_tracing.h>

#include "../bpf_testmod/bpf_testmod.h"



char _license[] SEC("license") = "GPL";



int rand;

int arr[1];



SEC("struct_ops/test_1")

int BPF_PROG(test_1_turn_off)

{

	return arr[rand]; /* potentially way out of range access */

}



SEC(".struct_ops.link")

struct bpf_testmod_ops ops = {

	.test_1 = (void *)test_1_turn_off,

};