The Tcpdump Group git mirrors - libpcap/blob - testprogs/fuzz/fuzz_pcap.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <fcntl.h>
   4 #include <errno.h>
   5
   6 #include <pcap/pcap.h>
   7
   8 FILE * outfile = NULL;
   9
  10 static int bufferToFile(const char * name, const uint8_t *Data, size_t Size) {
  11     FILE * fd;
  12     if (remove(name) != 0) {
  13         if (errno != ENOENT) {
  14             printf("failed remove, errno=%d\n", errno);
  15             return -1;
  16         }
  17     }
  18     fd = fopen(name, "wb");
  19     if (fd == NULL) {
  20         printf("failed open, errno=%d\n", errno);
  21         return -2;
  22     }
  23     if (fwrite (Data, 1, Size, fd) != Size) {
  24         fclose(fd);
  25         return -3;
  26     }
  27     fclose(fd);
  28     return 0;
  29 }
  30
  31 void fuzz_openFile(const char * name) {
  32     if (outfile != NULL) {
  33         fclose(outfile);
  34     }
  35     outfile = fopen(name, "w");
  36 }
  37
  38 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
  39     pcap_t * pkts;
  40     char errbuf[PCAP_ERRBUF_SIZE];
  41     const u_char *pkt;
  42     struct pcap_pkthdr *header;
  43     struct pcap_stat stats;
  44     int r;
  45
  46     //initialize output file
  47     if (outfile == NULL) {
  48         outfile = fopen("/dev/null", "w");
  49         if (outfile == NULL) {
  50             return 0;
  51         }
  52     }
  53
  54     //rewrite buffer to a file as libpcap does not have buffer inputs
  55     if (bufferToFile("/tmp/fuzz.pcap", Data, Size) < 0) {
  56         return 0;
  57     }
  58
  59     //initialize structure
  60     pkts = pcap_open_offline("/tmp/fuzz.pcap", errbuf);
  61     if (pkts == NULL) {
  62         fprintf(outfile, "Couldn't open pcap file %s\n", errbuf);
  63         return 0;
  64     }
  65
  66     //loop over packets
  67     r = pcap_next_ex(pkts, &header, &pkt);
  68     while (r > 0) {
  69         //TODO pcap_offline_filter
  70         fprintf(outfile, "packet length=%d/%d\n",header->caplen, header->len);
  71         r = pcap_next_ex(pkts, &header, &pkt);
  72     }
  73     if (pcap_stats(pkts, &stats) == 0) {
  74         fprintf(outfile, "number of packets=%d\n", stats.ps_recv);
  75     }
  76     //close structure
  77     pcap_close(pkts);
  78
  79     return 0;
  80 }