1// SPDX-License-Identifier: GPL-2.0
2
3/*
4 * Copyright 2020 Google LLC.
5 */
6
7#include "vmlinux.h"
8#include <bpf/bpf_helpers.h>
9#include <bpf/bpf_tracing.h>
10#include  <errno.h>
11
12struct {
13	__uint(type, BPF_MAP_TYPE_ARRAY);
14	__uint(max_entries, 1);
15	__type(key, __u32);
16	__type(value, __u64);
17} array SEC(".maps");
18
19struct {
20	__uint(type, BPF_MAP_TYPE_HASH);
21	__uint(max_entries, 1);
22	__type(key, __u32);
23	__type(value, __u64);
24} hash SEC(".maps");
25
26struct {
27	__uint(type, BPF_MAP_TYPE_LRU_HASH);
28	__uint(max_entries, 1);
29	__type(key, __u32);
30	__type(value, __u64);
31} lru_hash SEC(".maps");
32
33char _license[] SEC("license") = "GPL";
34
35int monitored_pid = 0;
36int mprotect_count = 0;
37int bprm_count = 0;
38
39SEC("lsm/file_mprotect")
40int BPF_PROG(test_int_hook, struct vm_area_struct *vma,
41	     unsigned long reqprot, unsigned long prot, int ret)
42{
43	if (ret != 0)
44		return ret;
45
46	__u32 pid = bpf_get_current_pid_tgid() >> 32;
47	int is_stack = 0;
48
49	is_stack = (vma->vm_start <= vma->vm_mm->start_stack &&
50		    vma->vm_end >= vma->vm_mm->start_stack);
51
52	if (is_stack && monitored_pid == pid) {
53		mprotect_count++;
54		ret = -EPERM;
55	}
56
57	return ret;
58}
59
60SEC("lsm.s/bprm_committed_creds")
61int BPF_PROG(test_void_hook, struct linux_binprm *bprm)
62{
63	__u32 pid = bpf_get_current_pid_tgid() >> 32;
64	char args[64];
65	__u32 key = 0;
66	__u64 *value;
67
68	if (monitored_pid == pid)
69		bprm_count++;
70
71	bpf_copy_from_user(args, sizeof(args), (void *)bprm->vma->vm_mm->arg_start);
72	bpf_copy_from_user(args, sizeof(args), (void *)bprm->mm->arg_start);
73
74	value = bpf_map_lookup_elem(&array, &key);
75	if (value)
76		*value = 0;
77	value = bpf_map_lookup_elem(&hash, &key);
78	if (value)
79		*value = 0;
80	value = bpf_map_lookup_elem(&lru_hash, &key);
81	if (value)
82		*value = 0;
83
84	return 0;
85}
86SEC("lsm/task_free") /* lsm/ is ok, lsm.s/ fails */
87int BPF_PROG(test_task_free, struct task_struct *task)
88{
89	return 0;
90}
91
92int copy_test = 0;
93
94SEC("fentry.s/__x64_sys_setdomainname")
95int BPF_PROG(test_sys_setdomainname, struct pt_regs *regs)
96{
97	void *ptr = (void *)PT_REGS_PARM1(regs);
98	int len = PT_REGS_PARM2(regs);
99	int buf = 0;
100	long ret;
101
102	ret = bpf_copy_from_user(&buf, sizeof(buf), ptr);
103	if (len == -2 && ret == 0 && buf == 1234)
104		copy_test++;
105	if (len == -3 && ret == -EFAULT)
106		copy_test++;
107	if (len == -4 && ret == -EFAULT)
108		copy_test++;
109	return 0;
110}
111