Commit 898cbca4 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add uptr failure verifier tests 



Add verifier tests to ensure invalid uptr usages are rejected.

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20241023234759.860539-12-martin.lau@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent cbf9f849

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

+2 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include "uptr_test_common.h"

#include "task_ls_uptr.skel.h"

#include "uptr_update_failure.skel.h"

#include "uptr_failure.skel.h"



static void test_sys_enter_exit(void)

{
@@ -467,4 +468,5 @@ void test_task_local_storage(void) 
		test_uptr_across_pages();

	if (test__start_subtest("uptr_update_failure"))

		test_uptr_update_failure();

	RUN_TESTS(uptr_failure);

}

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

0 → 100644
+105 −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_helpers.h>

#include "bpf_experimental.h"

#include "bpf_misc.h"

#include "uptr_test_common.h"



struct {

	__uint(type, BPF_MAP_TYPE_TASK_STORAGE);

	__uint(map_flags, BPF_F_NO_PREALLOC);

	__type(key, int);

	__type(value, struct value_type);

} datamap SEC(".maps");



SEC("?syscall")

__failure __msg("store to uptr disallowed")

int uptr_write(const void *ctx)

{

	struct task_struct *task;

	struct value_type *v;



	task = bpf_get_current_task_btf();

	v = bpf_task_storage_get(&datamap, task, 0,

				 BPF_LOCAL_STORAGE_GET_F_CREATE);

	if (!v)

		return 0;



	v->udata = NULL;

	return 0;

}



SEC("?syscall")

__failure __msg("store to uptr disallowed")

int uptr_write_nested(const void *ctx)

{

	struct task_struct *task;

	struct value_type *v;



	task = bpf_get_current_task_btf();

	v = bpf_task_storage_get(&datamap, task, 0,

				 BPF_LOCAL_STORAGE_GET_F_CREATE);

	if (!v)

		return 0;



	v->nested.udata = NULL;

	return 0;

}



SEC("?syscall")

__failure __msg("R1 invalid mem access 'mem_or_null'")

int uptr_no_null_check(const void *ctx)

{

	struct task_struct *task;

	struct value_type *v;



	task = bpf_get_current_task_btf();

	v = bpf_task_storage_get(&datamap, task, 0,

				 BPF_LOCAL_STORAGE_GET_F_CREATE);

	if (!v)

		return 0;



	v->udata->result = 0;



	return 0;

}



SEC("?syscall")

__failure __msg("doesn't point to kptr")

int uptr_kptr_xchg(const void *ctx)

{

	struct task_struct *task;

	struct value_type *v;



	task = bpf_get_current_task_btf();

	v = bpf_task_storage_get(&datamap, task, 0,

				 BPF_LOCAL_STORAGE_GET_F_CREATE);

	if (!v)

		return 0;



	bpf_kptr_xchg(&v->udata, NULL);



	return 0;

}



SEC("?syscall")

__failure __msg("invalid mem access 'scalar'")

int uptr_obj_new(const void *ctx)

{

	struct value_type *v;



	v = bpf_obj_new(typeof(*v));

	if (!v)

		return 0;



	if (v->udata)

		v->udata->result = 0;



	bpf_obj_drop(v);



	return 0;

}



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