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
|
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <pcap/pcap.h>
FILE * outfile = NULL;
static int bufferToFile(const char * name, const uint8_t *Data, size_t Size) {
FILE * fd;
if (remove(name) != 0) {
if (errno != ENOENT) {
printf("failed remove, errno=%d\n", errno);
return -1;
}
}
fd = fopen(name, "wb");
if (fd == NULL) {
printf("failed open, errno=%d\n", errno);
return -2;
}
if (fwrite (Data, 1, Size, fd) != Size) {
fclose(fd);
return -3;
}
fclose(fd);
return 0;
}
void fuzz_openFile(const char * name) {
if (outfile != NULL) {
fclose(outfile);
}
outfile = fopen(name, "w");
}
int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
pcap_t * pkts;
char errbuf[PCAP_ERRBUF_SIZE];
const u_char *pkt;
struct pcap_pkthdr *header;
int r;
size_t filterSize;
char * filter;
struct bpf_program bpf;
//initialize output file
if (outfile == NULL) {
outfile = fopen("/dev/null", "w");
if (outfile == NULL) {
return 0;
}
}
if (Size < 1) {
return 0;
}
filterSize = Data[0];
if (Size < 1+filterSize || filterSize == 0) {
return 0;
}
//rewrite buffer to a file as libpcap does not have buffer inputs
if (bufferToFile("/tmp/fuzz.pcap", Data+1+filterSize, Size-(1+filterSize)) < 0) {
return 0;
}
//initialize structure
pkts = pcap_open_offline("/tmp/fuzz.pcap", errbuf);
if (pkts == NULL) {
fprintf(outfile, "Couldn't open pcap file %s\n", errbuf);
return 0;
}
filter = malloc(filterSize);
memcpy(filter, Data+1, filterSize);
//null terminate string
filter[filterSize-1] = 0;
if (pcap_compile(pkts, &bpf, filter, 1, PCAP_NETMASK_UNKNOWN) == 0) {
//loop over packets
r = pcap_next_ex(pkts, &header, &pkt);
while (r > 0) {
//checks filter
fprintf(outfile, "packet length=%d/%d filter=%d\n",header->caplen, header->len, pcap_offline_filter(&bpf, header, pkt));
r = pcap_next_ex(pkts, &header, &pkt);
}
//close structure
pcap_close(pkts);
pcap_freecode(&bpf);
}
else {
pcap_close(pkts);
}
free(filter);
return 0;
}
|
