1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2020 Google LLC.
*/
#include "vmlinux.h"
#include <errno.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include "bpf_misc.h"
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u64);
} array SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u64);
} hash SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u64);
} lru_hash SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u64);
} percpu_array SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u64);
} percpu_hash SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_LRU_PERCPU_HASH);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u64);
} lru_percpu_hash SEC(".maps");
struct inner_map {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, __u64);
} inner_map SEC(".maps");
struct outer_arr {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 1);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
__array(values, struct inner_map);
} outer_arr SEC(".maps") = {
.values = { [0] = &inner_map },
};
struct outer_hash {
__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
__uint(max_entries, 1);
__uint(key_size, sizeof(int));
__array(values, struct inner_map);
} outer_hash SEC(".maps") = {
.values = { [0] = &inner_map },
};
char _license[] SEC("license") = "GPL";
int monitored_pid = 0;
int mprotect_count = 0;
int bprm_count = 0;
__u32 inode_identity_idmap_seen = 0;
__u32 inode_idmapped_mount_seen = 0;
enum {
INODE_IDMAP_CREATE = 1U << 0,
INODE_IDMAP_LINK = 1U << 1,
INODE_IDMAP_SYMLINK = 1U << 2,
INODE_IDMAP_MKDIR = 1U << 3,
INODE_IDMAP_MKNOD = 1U << 4,
INODE_IDMAP_PERMISSION = 1U << 5,
};
static __always_inline bool is_monitored_idmap(struct mnt_idmap *idmap)
{
__u32 pid = bpf_get_current_pid_tgid() >> 32;
return monitored_pid == pid && idmap;
}
static __always_inline bool is_identity_idmap(struct mnt_idmap *idmap)
{
return idmap->uid_map.nr_extents == 0 &&
idmap->gid_map.nr_extents == 0;
}
static __always_inline int record_inode_idmap(struct mnt_idmap *idmap,
__u32 hook, int ret)
{
if (ret || !is_monitored_idmap(idmap))
return ret;
if (is_identity_idmap(idmap))
inode_identity_idmap_seen |= hook;
else
inode_idmapped_mount_seen |= hook;
return 0;
}
SEC("lsm/inode_create")
int BPF_PROG(test_inode_create, struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, int ret)
{
return record_inode_idmap(idmap, INODE_IDMAP_CREATE, ret);
}
SEC("lsm/inode_link")
int BPF_PROG(test_inode_link, struct mnt_idmap *idmap,
struct dentry *old_dentry, struct inode *dir,
struct dentry *new_dentry, int ret)
{
return record_inode_idmap(idmap, INODE_IDMAP_LINK, ret);
}
SEC("lsm/inode_symlink")
int BPF_PROG(test_inode_symlink, struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, const char *old_name, int ret)
{
return record_inode_idmap(idmap, INODE_IDMAP_SYMLINK, ret);
}
SEC("lsm/inode_mkdir")
int BPF_PROG(test_inode_mkdir, struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, int ret)
{
return record_inode_idmap(idmap, INODE_IDMAP_MKDIR, ret);
}
SEC("lsm/inode_mknod")
int BPF_PROG(test_inode_mknod, struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, dev_t dev, int ret)
{
return record_inode_idmap(idmap, INODE_IDMAP_MKNOD, ret);
}
SEC("lsm/inode_permission")
int BPF_PROG(test_inode_permission, struct mnt_idmap *idmap,
struct inode *inode, int mask, int ret)
{
return record_inode_idmap(idmap, INODE_IDMAP_PERMISSION, ret);
}
SEC("lsm/file_mprotect")
int BPF_PROG(test_int_hook, struct vm_area_struct *vma,
unsigned long reqprot, unsigned long prot, int ret)
{
struct mm_struct *mm = vma->vm_mm;
if (ret != 0 || !mm)
return ret;
__s32 pid = bpf_get_current_pid_tgid() >> 32;
int is_stack = 0;
is_stack = (vma->vm_start <= mm->start_stack &&
vma->vm_end >= mm->start_stack);
if (is_stack && monitored_pid == pid) {
mprotect_count++;
ret = -EPERM;
}
return ret;
}
SEC("lsm.s/bprm_committed_creds")
int BPF_PROG(test_void_hook, struct linux_binprm *bprm)
{
__u32 pid = bpf_get_current_pid_tgid() >> 32;
struct inner_map *inner_map;
struct mm_struct *mm;
char args[64];
__u32 key = 0;
__u64 *value;
if (monitored_pid == pid)
bprm_count++;
bpf_copy_from_user(args, sizeof(args), (void *)bprm->vma->vm_mm->arg_start);
mm = bprm->mm;
if (mm)
bpf_copy_from_user(args, sizeof(args), (void *)mm->arg_start);
value = bpf_map_lookup_elem(&array, &key);
if (value)
*value = 0;
value = bpf_map_lookup_elem(&hash, &key);
if (value)
*value = 0;
value = bpf_map_lookup_elem(&lru_hash, &key);
if (value)
*value = 0;
value = bpf_map_lookup_elem(&percpu_array, &key);
if (value)
*value = 0;
value = bpf_map_lookup_elem(&percpu_hash, &key);
if (value)
*value = 0;
value = bpf_map_lookup_elem(&lru_percpu_hash, &key);
if (value)
*value = 0;
inner_map = bpf_map_lookup_elem(&outer_arr, &key);
if (inner_map) {
value = bpf_map_lookup_elem(inner_map, &key);
if (value)
*value = 0;
}
inner_map = bpf_map_lookup_elem(&outer_hash, &key);
if (inner_map) {
value = bpf_map_lookup_elem(inner_map, &key);
if (value)
*value = 0;
}
return 0;
}
SEC("lsm/task_free") /* lsm/ is ok, lsm.s/ fails */
int BPF_PROG(test_task_free, struct task_struct *task)
{
return 0;
}
int copy_test = 0;
SEC("fentry.s/" SYS_PREFIX "sys_setdomainname")
int BPF_PROG(test_sys_setdomainname, struct pt_regs *regs)
{
void *ptr = (void *)PT_REGS_PARM1_SYSCALL(regs);
int len = PT_REGS_PARM2_SYSCALL(regs);
int buf = 0;
long ret;
ret = bpf_copy_from_user(&buf, sizeof(buf), ptr);
if (len == -2 && ret == 0 && buf == 1234)
copy_test++;
if (len == -3 && ret == -EFAULT)
copy_test++;
if (len == -4 && ret == -EFAULT)
copy_test++;
return 0;
}
|
