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
|
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/time.h>
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/unistd.h>
#include <bpf/bpf.h>
#include "bpf_rlimit.h"
#define LOG_SIZE (1 << 20)
#define err(str...) printf("ERROR: " str)
static const struct bpf_insn code_sample[] = {
/* We need a few instructions to pass the min log length */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
BPF_FUNC_map_lookup_elem),
BPF_EXIT_INSN(),
};
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
}
static int load(char *log, size_t log_len, int log_level)
{
union bpf_attr attr;
bzero(&attr, sizeof(attr));
attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
attr.insn_cnt = (__u32)(sizeof(code_sample) / sizeof(struct bpf_insn));
attr.insns = ptr_to_u64(code_sample);
attr.license = ptr_to_u64("GPL");
attr.log_buf = ptr_to_u64(log);
attr.log_size = log_len;
attr.log_level = log_level;
return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
}
static void check_ret(int ret, int exp_errno)
{
if (ret > 0) {
close(ret);
err("broken sample loaded successfully!?\n");
exit(1);
}
if (!ret || errno != exp_errno) {
err("Program load returned: ret:%d/errno:%d, expected ret:%d/errno:%d\n",
ret, errno, -1, exp_errno);
exit(1);
}
}
static void check_ones(const char *buf, size_t len, const char *msg)
{
while (len--)
if (buf[len] != 1) {
err("%s", msg);
exit(1);
}
}
static void test_log_good(char *log, size_t buf_len, size_t log_len,
size_t exp_len, int exp_errno, const char *full_log)
{
size_t len;
int ret;
memset(log, 1, buf_len);
ret = load(log, log_len, 1);
check_ret(ret, exp_errno);
len = strnlen(log, buf_len);
if (len == buf_len) {
err("verifier did not NULL terminate the log\n");
exit(1);
}
if (exp_len && len != exp_len) {
err("incorrect log length expected:%zd have:%zd\n",
exp_len, len);
exit(1);
}
if (strchr(log, 1)) {
err("verifier leaked a byte through\n");
exit(1);
}
check_ones(log + len + 1, buf_len - len - 1,
"verifier wrote bytes past NULL termination\n");
if (memcmp(full_log, log, LOG_SIZE)) {
err("log did not match expected output\n");
exit(1);
}
}
static void test_log_bad(char *log, size_t log_len, int log_level)
{
int ret;
ret = load(log, log_len, log_level);
check_ret(ret, EINVAL);
if (log)
check_ones(log, LOG_SIZE,
"verifier touched log with bad parameters\n");
}
int main(int argc, char **argv)
{
char full_log[LOG_SIZE];
char log[LOG_SIZE];
size_t want_len;
int i;
memset(log, 1, LOG_SIZE);
/* Test incorrect attr */
printf("Test log_level 0...\n");
test_log_bad(log, LOG_SIZE, 0);
printf("Test log_size < 128...\n");
test_log_bad(log, 15, 1);
printf("Test log_buff = NULL...\n");
test_log_bad(NULL, LOG_SIZE, 1);
/* Test with log big enough */
printf("Test oversized buffer...\n");
test_log_good(full_log, LOG_SIZE, LOG_SIZE, 0, EACCES, full_log);
want_len = strlen(full_log);
printf("Test exact buffer...\n");
test_log_good(log, LOG_SIZE, want_len + 2, want_len, EACCES, full_log);
printf("Test undersized buffers...\n");
for (i = 0; i < 64; i++) {
full_log[want_len - i + 1] = 1;
full_log[want_len - i] = 0;
test_log_good(log, LOG_SIZE, want_len + 1 - i, want_len - i,
ENOSPC, full_log);
}
printf("test_verifier_log: OK\n");
return 0;
}
|
