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: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-8-kpsingh@chromium.org
This commit is contained in:
KP Singh 2020-08-25 20:29:19 +02:00 committed by Alexei Starovoitov
parent 30897832d8
commit cd324d7abb
2 changed files with 200 additions and 0 deletions

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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);
}

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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;
}