1 // SPDX-License-Identifier: GPL-2.0
2 
3 /*
4  * Copyright 2020 Google LLC.
5  */
6 
7 #include "vmlinux.h"
8 #include <errno.h>
9 #include <bpf/bpf_core_read.h>
10 #include <bpf/bpf_helpers.h>
11 #include <bpf/bpf_tracing.h>
12 #include "bpf_misc.h"
13 
14 struct {
15 	__uint(type, BPF_MAP_TYPE_ARRAY);
16 	__uint(max_entries, 1);
17 	__type(key, __u32);
18 	__type(value, __u64);
19 } array SEC(".maps");
20 
21 struct {
22 	__uint(type, BPF_MAP_TYPE_HASH);
23 	__uint(max_entries, 1);
24 	__type(key, __u32);
25 	__type(value, __u64);
26 } hash SEC(".maps");
27 
28 struct {
29 	__uint(type, BPF_MAP_TYPE_LRU_HASH);
30 	__uint(max_entries, 1);
31 	__type(key, __u32);
32 	__type(value, __u64);
33 } lru_hash SEC(".maps");
34 
35 struct {
36 	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
37 	__uint(max_entries, 1);
38 	__type(key, __u32);
39 	__type(value, __u64);
40 } percpu_array SEC(".maps");
41 
42 struct {
43 	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
44 	__uint(max_entries, 1);
45 	__type(key, __u32);
46 	__type(value, __u64);
47 } percpu_hash SEC(".maps");
48 
49 struct {
50 	__uint(type, BPF_MAP_TYPE_LRU_PERCPU_HASH);
51 	__uint(max_entries, 1);
52 	__type(key, __u32);
53 	__type(value, __u64);
54 } lru_percpu_hash SEC(".maps");
55 
56 struct inner_map {
57 	__uint(type, BPF_MAP_TYPE_ARRAY);
58 	__uint(max_entries, 1);
59 	__type(key, int);
60 	__type(value, __u64);
61 } inner_map SEC(".maps");
62 
63 struct outer_arr {
64 	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
65 	__uint(max_entries, 1);
66 	__uint(key_size, sizeof(int));
67 	__uint(value_size, sizeof(int));
68 	__array(values, struct inner_map);
69 } outer_arr SEC(".maps") = {
70 	.values = { [0] = &inner_map },
71 };
72 
73 struct outer_hash {
74 	__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
75 	__uint(max_entries, 1);
76 	__uint(key_size, sizeof(int));
77 	__array(values, struct inner_map);
78 } outer_hash SEC(".maps") = {
79 	.values = { [0] = &inner_map },
80 };
81 
82 char _license[] SEC("license") = "GPL";
83 
84 int monitored_pid = 0;
85 int mprotect_count = 0;
86 int bprm_count = 0;
87 
88 SEC("lsm/file_mprotect")
89 int BPF_PROG(test_int_hook, struct vm_area_struct *vma,
90 	     unsigned long reqprot, unsigned long prot, int ret)
91 {
92 	if (ret != 0)
93 		return ret;
94 
95 	__u32 pid = bpf_get_current_pid_tgid() >> 32;
96 	int is_stack = 0;
97 
98 	is_stack = (vma->vm_start <= vma->vm_mm->start_stack &&
99 		    vma->vm_end >= vma->vm_mm->start_stack);
100 
101 	if (is_stack && monitored_pid == pid) {
102 		mprotect_count++;
103 		ret = -EPERM;
104 	}
105 
106 	return ret;
107 }
108 
109 SEC("lsm.s/bprm_committed_creds")
110 int BPF_PROG(test_void_hook, struct linux_binprm *bprm)
111 {
112 	__u32 pid = bpf_get_current_pid_tgid() >> 32;
113 	struct inner_map *inner_map;
114 	char args[64];
115 	__u32 key = 0;
116 	__u64 *value;
117 
118 	if (monitored_pid == pid)
119 		bprm_count++;
120 
121 	bpf_copy_from_user(args, sizeof(args), (void *)bprm->vma->vm_mm->arg_start);
122 	bpf_copy_from_user(args, sizeof(args), (void *)bprm->mm->arg_start);
123 
124 	value = bpf_map_lookup_elem(&array, &key);
125 	if (value)
126 		*value = 0;
127 	value = bpf_map_lookup_elem(&hash, &key);
128 	if (value)
129 		*value = 0;
130 	value = bpf_map_lookup_elem(&lru_hash, &key);
131 	if (value)
132 		*value = 0;
133 	value = bpf_map_lookup_elem(&percpu_array, &key);
134 	if (value)
135 		*value = 0;
136 	value = bpf_map_lookup_elem(&percpu_hash, &key);
137 	if (value)
138 		*value = 0;
139 	value = bpf_map_lookup_elem(&lru_percpu_hash, &key);
140 	if (value)
141 		*value = 0;
142 	inner_map = bpf_map_lookup_elem(&outer_arr, &key);
143 	if (inner_map) {
144 		value = bpf_map_lookup_elem(inner_map, &key);
145 		if (value)
146 			*value = 0;
147 	}
148 	inner_map = bpf_map_lookup_elem(&outer_hash, &key);
149 	if (inner_map) {
150 		value = bpf_map_lookup_elem(inner_map, &key);
151 		if (value)
152 			*value = 0;
153 	}
154 
155 	return 0;
156 }
157 SEC("lsm/task_free") /* lsm/ is ok, lsm.s/ fails */
158 int BPF_PROG(test_task_free, struct task_struct *task)
159 {
160 	return 0;
161 }
162 
163 int copy_test = 0;
164 
165 SEC("fentry.s/" SYS_PREFIX "sys_setdomainname")
166 int BPF_PROG(test_sys_setdomainname, struct pt_regs *regs)
167 {
168 	void *ptr = (void *)PT_REGS_PARM1_SYSCALL(regs);
169 	int len = PT_REGS_PARM2_SYSCALL(regs);
170 	int buf = 0;
171 	long ret;
172 
173 	ret = bpf_copy_from_user(&buf, sizeof(buf), ptr);
174 	if (len == -2 && ret == 0 && buf == 1234)
175 		copy_test++;
176 	if (len == -3 && ret == -EFAULT)
177 		copy_test++;
178 	if (len == -4 && ret == -EFAULT)
179 		copy_test++;
180 	return 0;
181 }
182