Commit 1bc724af authored by David Vernet's avatar David Vernet Committed by Andrii Nakryiko
Browse files

selftests/bpf: Verify calling core kfuncs from BPF_PROG_TYPE_SYCALL 



Now that we can call some kfuncs from BPF_PROG_TYPE_SYSCALL progs, let's
add some selftests that verify as much. As a bonus, let's also verify
that we can't call the progs from raw tracepoints. Do do this, we add a
new selftest suite called verifier_kfunc_prog_types.

Signed-off-by: default avatarDavid Vernet <void@manifault.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarYonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240405143041.632519-3-void@manifault.com
parent a8e03b6b

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

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// SPDX-License-Identifier: GPL-2.0

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



#include <test_progs.h>



#include "verifier_kfunc_prog_types.skel.h"



void test_verifier_kfunc_prog_types(void)

{

	RUN_TESTS(verifier_kfunc_prog_types);

}

tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h

+1 −1
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@@ -13,7 +13,7 @@ struct __cgrps_kfunc_map_value { 
	struct cgroup __kptr * cgrp;

};



struct hash_map {

struct {

	__uint(type, BPF_MAP_TYPE_HASH);

	__type(key, int);

	__type(value, struct __cgrps_kfunc_map_value);

tools/testing/selftests/bpf/progs/task_kfunc_common.h

+1 −1
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@@ -13,7 +13,7 @@ struct __tasks_kfunc_map_value { 
	struct task_struct __kptr * task;

};



struct hash_map {

struct {

	__uint(type, BPF_MAP_TYPE_HASH);

	__type(key, int);

	__type(value, struct __tasks_kfunc_map_value);

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

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// SPDX-License-Identifier: GPL-2.0

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



#include <vmlinux.h>

#include <bpf/bpf_tracing.h>

#include <bpf/bpf_helpers.h>



#include "bpf_misc.h"

#include "cgrp_kfunc_common.h"

#include "cpumask_common.h"

#include "task_kfunc_common.h"



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



/***************

 * Task kfuncs *

 ***************/



static void task_kfunc_load_test(void)

{

	struct task_struct *current, *ref_1, *ref_2;



	current = bpf_get_current_task_btf();

	ref_1 = bpf_task_from_pid(current->pid);

	if (!ref_1)

		return;



	ref_2 = bpf_task_acquire(ref_1);

	if (ref_2)

		bpf_task_release(ref_2);

	bpf_task_release(ref_1);

}



SEC("raw_tp")

__failure __msg("calling kernel function")

int BPF_PROG(task_kfunc_raw_tp)

{

	task_kfunc_load_test();

	return 0;

}



SEC("syscall")

__success

int BPF_PROG(task_kfunc_syscall)

{

	task_kfunc_load_test();

	return 0;

}



/*****************

 * cgroup kfuncs *

 *****************/



static void cgrp_kfunc_load_test(void)

{

	struct cgroup *cgrp, *ref;



	cgrp = bpf_cgroup_from_id(0);

	if (!cgrp)

		return;



	ref = bpf_cgroup_acquire(cgrp);

	if (!ref) {

		bpf_cgroup_release(cgrp);

		return;

	}



	bpf_cgroup_release(ref);

	bpf_cgroup_release(cgrp);

}



SEC("raw_tp")

__failure __msg("calling kernel function")

int BPF_PROG(cgrp_kfunc_raw_tp)

{

	cgrp_kfunc_load_test();

	return 0;

}



SEC("syscall")

__success

int BPF_PROG(cgrp_kfunc_syscall)

{

	cgrp_kfunc_load_test();

	return 0;

}



/******************

 * cpumask kfuncs *

 ******************/



static void cpumask_kfunc_load_test(void)

{

	struct bpf_cpumask *alloc, *ref;



	alloc = bpf_cpumask_create();

	if (!alloc)

		return;



	ref = bpf_cpumask_acquire(alloc);

	bpf_cpumask_set_cpu(0, alloc);

	bpf_cpumask_test_cpu(0, (const struct cpumask *)ref);



	bpf_cpumask_release(ref);

	bpf_cpumask_release(alloc);

}



SEC("raw_tp")

__failure __msg("calling kernel function")

int BPF_PROG(cpumask_kfunc_raw_tp)

{

	cpumask_kfunc_load_test();

	return 0;

}



SEC("syscall")

__success

int BPF_PROG(cpumask_kfunc_syscall)

{

	cpumask_kfunc_load_test();

	return 0;

}