1// SPDX-License-Identifier: GPL-2.0
 2/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
 3
 4#include "vmlinux.h"
 5#include <bpf/bpf_helpers.h>
 6#include <bpf/bpf_tracing.h>
 7#include "bpf_kfuncs.h"
 8
 9char _license[] SEC("license") = "GPL";
10
11__u32 monitored_pid;
12__u32 found_xattr;
13
14static const char expected_value[] = "hello";
15char value[32];
16
17SEC("lsm.s/file_open")
18int BPF_PROG(test_file_open, struct file *f)
19{
20	struct bpf_dynptr value_ptr;
21	__u32 pid;
22	int ret;
23
24	pid = bpf_get_current_pid_tgid() >> 32;
25	if (pid != monitored_pid)
26		return 0;
27
28	bpf_dynptr_from_mem(value, sizeof(value), 0, &value_ptr);
29
30	ret = bpf_get_file_xattr(f, "user.kfuncs", &value_ptr);
31	if (ret != sizeof(expected_value))
32		return 0;
33	if (bpf_strncmp(value, ret, expected_value))
34		return 0;
35	found_xattr = 1;
36	return 0;
37}