Commit cd324d7a authored by KP Singh's avatar KP Singh Committed by Alexei Starovoitov
Browse files

bpf: Add selftests for local_storage 



inode_local_storage:

* Hook to the file_open and inode_unlink LSM hooks.
* Create and unlink a temporary file.
* Store some information in the inode's bpf_local_storage during
  file_open.
* Verify that this information exists when the file is unlinked.

sk_local_storage:

* Hook to the socket_post_create and socket_bind LSM hooks.
* Open and bind a socket and set the sk_storage in the
  socket_post_create hook using the start_server helper.
* Verify if the information is set in the socket_bind hook.

Signed-off-by: default avatarKP Singh <kpsingh@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-8-kpsingh@chromium.org
parent 30897832

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

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// SPDX-License-Identifier: GPL-2.0



/*

 * Copyright (C) 2020 Google LLC.

 */



#include <test_progs.h>

#include <linux/limits.h>



#include "local_storage.skel.h"

#include "network_helpers.h"



int create_and_unlink_file(void)

{

	char fname[PATH_MAX] = "/tmp/fileXXXXXX";

	int fd;



	fd = mkstemp(fname);

	if (fd < 0)

		return fd;



	close(fd);

	unlink(fname);

	return 0;

}



void test_test_local_storage(void)

{

	struct local_storage *skel = NULL;

	int err, duration = 0, serv_sk = -1;



	skel = local_storage__open_and_load();

	if (CHECK(!skel, "skel_load", "lsm skeleton failed\n"))

		goto close_prog;



	err = local_storage__attach(skel);

	if (CHECK(err, "attach", "lsm attach failed: %d\n", err))

		goto close_prog;



	skel->bss->monitored_pid = getpid();



	err = create_and_unlink_file();

	if (CHECK(err < 0, "exec_cmd", "err %d errno %d\n", err, errno))

		goto close_prog;



	CHECK(skel->data->inode_storage_result != 0, "inode_storage_result",

	      "inode_local_storage not set\n");



	serv_sk = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);

	if (CHECK(serv_sk < 0, "start_server", "failed to start server\n"))

		goto close_prog;



	CHECK(skel->data->sk_storage_result != 0, "sk_storage_result",

	      "sk_local_storage not set\n");



	close(serv_sk);



close_prog:

	local_storage__destroy(skel);

}

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

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// SPDX-License-Identifier: GPL-2.0



/*

 * Copyright 2020 Google LLC.

 */



#include <errno.h>

#include <linux/bpf.h>

#include <stdbool.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



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



#define DUMMY_STORAGE_VALUE 0xdeadbeef



int monitored_pid = 0;

int inode_storage_result = -1;

int sk_storage_result = -1;



struct dummy_storage {

	__u32 value;

};



struct {

	__uint(type, BPF_MAP_TYPE_INODE_STORAGE);

	__uint(map_flags, BPF_F_NO_PREALLOC);

	__type(key, int);

	__type(value, struct dummy_storage);

} inode_storage_map SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_SK_STORAGE);

	__uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE);

	__type(key, int);

	__type(value, struct dummy_storage);

} sk_storage_map SEC(".maps");



/* TODO Use vmlinux.h once BTF pruning for embedded types is fixed.

 */

struct sock {} __attribute__((preserve_access_index));

struct sockaddr {} __attribute__((preserve_access_index));

struct socket {

	struct sock *sk;

} __attribute__((preserve_access_index));



struct inode {} __attribute__((preserve_access_index));

struct dentry {

	struct inode *d_inode;

} __attribute__((preserve_access_index));

struct file {

	struct inode *f_inode;

} __attribute__((preserve_access_index));





SEC("lsm/inode_unlink")

int BPF_PROG(unlink_hook, struct inode *dir, struct dentry *victim)

{

	__u32 pid = bpf_get_current_pid_tgid() >> 32;

	struct dummy_storage *storage;



	if (pid != monitored_pid)

		return 0;



	storage = bpf_inode_storage_get(&inode_storage_map, victim->d_inode, 0,

				     BPF_SK_STORAGE_GET_F_CREATE);

	if (!storage)

		return 0;



	if (storage->value == DUMMY_STORAGE_VALUE)

		inode_storage_result = -1;



	inode_storage_result =

		bpf_inode_storage_delete(&inode_storage_map, victim->d_inode);



	return 0;

}



SEC("lsm/socket_bind")

int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address,

	     int addrlen)

{

	__u32 pid = bpf_get_current_pid_tgid() >> 32;

	struct dummy_storage *storage;



	if (pid != monitored_pid)

		return 0;



	storage = bpf_sk_storage_get(&sk_storage_map, sock->sk, 0,

				     BPF_SK_STORAGE_GET_F_CREATE);

	if (!storage)

		return 0;



	if (storage->value == DUMMY_STORAGE_VALUE)

		sk_storage_result = -1;



	sk_storage_result = bpf_sk_storage_delete(&sk_storage_map, sock->sk);

	return 0;

}



SEC("lsm/socket_post_create")

int BPF_PROG(socket_post_create, struct socket *sock, int family, int type,

	     int protocol, int kern)

{

	__u32 pid = bpf_get_current_pid_tgid() >> 32;

	struct dummy_storage *storage;



	if (pid != monitored_pid)

		return 0;



	storage = bpf_sk_storage_get(&sk_storage_map, sock->sk, 0,

				     BPF_SK_STORAGE_GET_F_CREATE);

	if (!storage)

		return 0;



	storage->value = DUMMY_STORAGE_VALUE;



	return 0;

}



SEC("lsm/file_open")

int BPF_PROG(file_open, struct file *file)

{

	__u32 pid = bpf_get_current_pid_tgid() >> 32;

	struct dummy_storage *storage;



	if (pid != monitored_pid)

		return 0;



	if (!file->f_inode)

		return 0;



	storage = bpf_inode_storage_get(&inode_storage_map, file->f_inode, 0,

				     BPF_LOCAL_STORAGE_GET_F_CREATE);

	if (!storage)

		return 0;



	storage->value = DUMMY_STORAGE_VALUE;

	return 0;

}

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