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 #include "bpf_rlimit.h"
15
16 #define LOG_SIZE (1 << 20)
17
18 #define err(str...) printf("ERROR: " str)
19
20 static const struct bpf_insn code_sample[] = {
21 /* We need a few instructions to pass the min log length */
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_MOV64_IMM(BPF_REG_0, 0),
37 BPF_MOV64_IMM(BPF_REG_0, 0),
38 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
39 BPF_FUNC_map_lookup_elem),
40 BPF_EXIT_INSN(),
41 };
42
ptr_to_u64(const void * ptr)43 static inline __u64 ptr_to_u64(const void *ptr)
44 {
45 return (__u64) (unsigned long) ptr;
46 }
47
load(char * log,size_t log_len,int log_level)48 static int load(char *log, size_t log_len, int log_level)
49 {
50 union bpf_attr attr;
51
52 bzero(&attr, sizeof(attr));
53 attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
54 attr.insn_cnt = (__u32)(sizeof(code_sample) / sizeof(struct bpf_insn));
55 attr.insns = ptr_to_u64(code_sample);
56 attr.license = ptr_to_u64("GPL");
57 attr.log_buf = ptr_to_u64(log);
58 attr.log_size = log_len;
59 attr.log_level = log_level;
60
61 return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
62 }
63
check_ret(int ret,int exp_errno)64 static void check_ret(int ret, int exp_errno)
65 {
66 if (ret > 0) {
67 close(ret);
68 err("broken sample loaded successfully!?\n");
69 exit(1);
70 }
71
72 if (!ret || errno != exp_errno) {
73 err("Program load returned: ret:%d/errno:%d, expected ret:%d/errno:%d\n",
74 ret, errno, -1, exp_errno);
75 exit(1);
76 }
77 }
78
check_ones(const char * buf,size_t len,const char * msg)79 static void check_ones(const char *buf, size_t len, const char *msg)
80 {
81 while (len--)
82 if (buf[len] != 1) {
83 err("%s", msg);
84 exit(1);
85 }
86 }
87
test_log_good(char * log,size_t buf_len,size_t log_len,size_t exp_len,int exp_errno,const char * full_log)88 static void test_log_good(char *log, size_t buf_len, size_t log_len,
89 size_t exp_len, int exp_errno, const char *full_log)
90 {
91 size_t len;
92 int ret;
93
94 memset(log, 1, buf_len);
95
96 ret = load(log, log_len, 1);
97 check_ret(ret, exp_errno);
98
99 len = strnlen(log, buf_len);
100 if (len == buf_len) {
101 err("verifier did not NULL terminate the log\n");
102 exit(1);
103 }
104 if (exp_len && len != exp_len) {
105 err("incorrect log length expected:%zd have:%zd\n",
106 exp_len, len);
107 exit(1);
108 }
109
110 if (strchr(log, 1)) {
111 err("verifier leaked a byte through\n");
112 exit(1);
113 }
114
115 check_ones(log + len + 1, buf_len - len - 1,
116 "verifier wrote bytes past NULL termination\n");
117
118 if (memcmp(full_log, log, LOG_SIZE)) {
119 err("log did not match expected output\n");
120 exit(1);
121 }
122 }
123
test_log_bad(char * log,size_t log_len,int log_level)124 static void test_log_bad(char *log, size_t log_len, int log_level)
125 {
126 int ret;
127
128 ret = load(log, log_len, log_level);
129 check_ret(ret, EINVAL);
130 if (log)
131 check_ones(log, LOG_SIZE,
132 "verifier touched log with bad parameters\n");
133 }
134
main(int argc,char ** argv)135 int main(int argc, char **argv)
136 {
137 char full_log[LOG_SIZE];
138 char log[LOG_SIZE];
139 size_t want_len;
140 int i;
141
142 memset(log, 1, LOG_SIZE);
143
144 /* Test incorrect attr */
145 printf("Test log_level 0...\n");
146 test_log_bad(log, LOG_SIZE, 0);
147
148 printf("Test log_size < 128...\n");
149 test_log_bad(log, 15, 1);
150
151 printf("Test log_buff = NULL...\n");
152 test_log_bad(NULL, LOG_SIZE, 1);
153
154 /* Test with log big enough */
155 printf("Test oversized buffer...\n");
156 test_log_good(full_log, LOG_SIZE, LOG_SIZE, 0, EACCES, full_log);
157
158 want_len = strlen(full_log);
159
160 printf("Test exact buffer...\n");
161 test_log_good(log, LOG_SIZE, want_len + 2, want_len, EACCES, full_log);
162
163 printf("Test undersized buffers...\n");
164 for (i = 0; i < 64; i++) {
165 full_log[want_len - i + 1] = 1;
166 full_log[want_len - i] = 0;
167
168 test_log_good(log, LOG_SIZE, want_len + 1 - i, want_len - i,
169 ENOSPC, full_log);
170 }
171
172 printf("test_verifier_log: OK\n");
173 return 0;
174 }
175