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
 20static 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
 43static inline __u64 ptr_to_u64(const void *ptr)
 44{
 45	return (__u64) (unsigned long) ptr;
 46}
 47
 48static 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
 64static 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
 79static 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
 88static 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
124static 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
135int 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}