1 #include <errno.h>
2 #include <stdlib.h>
3 #include <stdio.h>
4 #include <string.h>
5 #include <unistd.h>
6 #include <sys/time.h>
7
8 #include <linux/bpf.h>
9 #include <linux/filter.h>
10 #include <linux/unistd.h>
11
12 #include <bpf/bpf.h>
13
14 #define LOG_SIZE (1 << 20)
15
16 #define err(str...) printf("ERROR: " str)
17
18 static const struct bpf_insn code_sample[] = {
19 /* We need a few instructions to pass the min log length */
20 BPF_MOV64_IMM(BPF_REG_0, 0),
21 BPF_MOV64_IMM(BPF_REG_0, 0),
22 BPF_MOV64_IMM(BPF_REG_0, 0),
23 BPF_MOV64_IMM(BPF_REG_0, 0),
24 BPF_MOV64_IMM(BPF_REG_0, 0),
25 BPF_MOV64_IMM(BPF_REG_0, 0),
26 BPF_MOV64_IMM(BPF_REG_0, 0),
27 BPF_MOV64_IMM(BPF_REG_0, 0),
28 BPF_MOV64_IMM(BPF_REG_0, 0),
29 BPF_MOV64_IMM(BPF_REG_0, 0),
30 BPF_MOV64_IMM(BPF_REG_0, 0),
31 BPF_MOV64_IMM(BPF_REG_0, 0),
32 BPF_MOV64_IMM(BPF_REG_0, 0),
33 BPF_MOV64_IMM(BPF_REG_0, 0),
34 BPF_MOV64_IMM(BPF_REG_0, 0),
35 BPF_MOV64_IMM(BPF_REG_0, 0),
36 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
37 BPF_FUNC_map_lookup_elem),
38 BPF_EXIT_INSN(),
39 };
40
ptr_to_u64(const void * ptr)41 static inline __u64 ptr_to_u64(const void *ptr)
42 {
43 return (__u64) (unsigned long) ptr;
44 }
45
load(char * log,size_t log_len,int log_level)46 static int load(char *log, size_t log_len, int log_level)
47 {
48 union bpf_attr attr;
49
50 bzero(&attr, sizeof(attr));
51 attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
52 attr.insn_cnt = (__u32)(sizeof(code_sample) / sizeof(struct bpf_insn));
53 attr.insns = ptr_to_u64(code_sample);
54 attr.license = ptr_to_u64("GPL");
55 attr.log_buf = ptr_to_u64(log);
56 attr.log_size = log_len;
57 attr.log_level = log_level;
58
59 return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
60 }
61
check_ret(int ret,int exp_errno)62 static void check_ret(int ret, int exp_errno)
63 {
64 if (ret > 0) {
65 close(ret);
66 err("broken sample loaded successfully!?\n");
67 exit(1);
68 }
69
70 if (!ret || errno != exp_errno) {
71 err("Program load returned: ret:%d/errno:%d, expected ret:%d/errno:%d\n",
72 ret, errno, -1, exp_errno);
73 exit(1);
74 }
75 }
76
check_ones(const char * buf,size_t len,const char * msg)77 static void check_ones(const char *buf, size_t len, const char *msg)
78 {
79 while (len--)
80 if (buf[len] != 1) {
81 err("%s", msg);
82 exit(1);
83 }
84 }
85
test_log_good(char * log,size_t buf_len,size_t log_len,size_t exp_len,int exp_errno,const char * full_log)86 static void test_log_good(char *log, size_t buf_len, size_t log_len,
87 size_t exp_len, int exp_errno, const char *full_log)
88 {
89 size_t len;
90 int ret;
91
92 memset(log, 1, buf_len);
93
94 ret = load(log, log_len, 1);
95 check_ret(ret, exp_errno);
96
97 len = strnlen(log, buf_len);
98 if (len == buf_len) {
99 err("verifier did not NULL terminate the log\n");
100 exit(1);
101 }
102 if (exp_len && len != exp_len) {
103 err("incorrect log length expected:%zd have:%zd\n",
104 exp_len, len);
105 exit(1);
106 }
107
108 if (strchr(log, 1)) {
109 err("verifier leaked a byte through\n");
110 exit(1);
111 }
112
113 check_ones(log + len + 1, buf_len - len - 1,
114 "verifier wrote bytes past NULL termination\n");
115
116 if (memcmp(full_log, log, LOG_SIZE)) {
117 err("log did not match expected output\n");
118 exit(1);
119 }
120 }
121
test_log_bad(char * log,size_t log_len,int log_level)122 static void test_log_bad(char *log, size_t log_len, int log_level)
123 {
124 int ret;
125
126 ret = load(log, log_len, log_level);
127 check_ret(ret, EINVAL);
128 if (log)
129 check_ones(log, LOG_SIZE,
130 "verifier touched log with bad parameters\n");
131 }
132
main(int argc,char ** argv)133 int main(int argc, char **argv)
134 {
135 char full_log[LOG_SIZE];
136 char log[LOG_SIZE];
137 size_t want_len;
138 int i;
139
140 memset(log, 1, LOG_SIZE);
141
142 /* Use libbpf 1.0 API mode */
143 libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
144
145 /* Test incorrect attr */
146 printf("Test log_level 0...\n");
147 test_log_bad(log, LOG_SIZE, 0);
148
149 printf("Test log_size < 128...\n");
150 test_log_bad(log, 15, 1);
151
152 printf("Test log_buff = NULL...\n");
153 test_log_bad(NULL, LOG_SIZE, 1);
154
155 /* Test with log big enough */
156 printf("Test oversized buffer...\n");
157 test_log_good(full_log, LOG_SIZE, LOG_SIZE, 0, EACCES, full_log);
158
159 want_len = strlen(full_log);
160
161 printf("Test exact buffer...\n");
162 test_log_good(log, LOG_SIZE, want_len + 2, want_len, EACCES, full_log);
163
164 printf("Test undersized buffers...\n");
165 for (i = 0; i < 64; i++) {
166 full_log[want_len - i + 1] = 1;
167 full_log[want_len - i] = 0;
168
169 test_log_good(log, LOG_SIZE, want_len + 1 - i, want_len - i,
170 ENOSPC, full_log);
171 }
172
173 printf("test_verifier_log: OK\n");
174 return 0;
175 }
176