1// SPDX-License-Identifier: GPL-2.0
 2/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
 3
 4#include "vmlinux.h"
 5#include <errno.h>
 6#include <bpf/bpf_helpers.h>
 7#include <bpf/bpf_tracing.h>
 8#include "bpf_kfuncs.h"
 9
10char _license[] SEC("license") = "GPL";
11
12__u32 monitored_pid;
13__u32 found_xattr_from_file;
14__u32 found_xattr_from_dentry;
15
16static const char expected_value[] = "hello";
17char value1[32];
18char value2[32];
19
20SEC("lsm.s/file_open")
21int BPF_PROG(test_file_open, struct file *f)
22{
23	struct bpf_dynptr value_ptr;
24	__u32 pid;
25	int ret;
26
27	pid = bpf_get_current_pid_tgid() >> 32;
28	if (pid != monitored_pid)
29		return 0;
30
31	bpf_dynptr_from_mem(value1, sizeof(value1), 0, &value_ptr);
32
33	ret = bpf_get_file_xattr(f, "user.kfuncs", &value_ptr);
34	if (ret != sizeof(expected_value))
35		return 0;
36	if (bpf_strncmp(value1, ret, expected_value))
37		return 0;
38	found_xattr_from_file = 1;
39	return 0;
40}
41
42SEC("lsm.s/inode_getxattr")
43int BPF_PROG(test_inode_getxattr, struct dentry *dentry, char *name)
44{
45	struct bpf_dynptr value_ptr;
46	__u32 pid;
47	int ret;
48
49	pid = bpf_get_current_pid_tgid() >> 32;
50	if (pid != monitored_pid)
51		return 0;
52
53	bpf_dynptr_from_mem(value2, sizeof(value2), 0, &value_ptr);
54
55	ret = bpf_get_dentry_xattr(dentry, "user.kfuncs", &value_ptr);
56	if (ret != sizeof(expected_value))
57		return 0;
58	if (bpf_strncmp(value2, ret, expected_value))
59		return 0;
60	found_xattr_from_dentry = 1;
61
62	/* return non-zero to fail getxattr from user space */
63	return -EINVAL;
64}

 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}