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/*
*
* libnet 1.1
* Build a TFTP scanner using payload
*
* Copyright (c) 2003 Frédéric Raynal <pappy@security-labs.org>
* All rights reserved.
*
* Ex:
* ./tftp -s 192.168.0.1 -d 192.168.0.66 -p plop
*
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#if (HAVE_CONFIG_H)
#include "../include/config.h"
#endif
#include "./libnet_test.h"
int
main(int argc, char *argv[])
{
int c;
libnet_t *l;
u_long src_ip, dst_ip;
char errbuf[LIBNET_ERRBUF_SIZE];
libnet_ptag_t udp = 0, ip = 0;
char *filename = "/etc/passwd";
char mode[] = "netascii";
u_char *payload = NULL;
uint payload_s = 0;
printf("libnet 1.1 packet shaping: UDP + payload[raw] == TFTP\n");
/*
* Initialize the library. Root priviledges are required.
*/
l = libnet_init(
LIBNET_RAW4, /* injection type */
NULL, /* network interface */
errbuf); /* error buffer */
if (l == NULL)
{
fprintf(stderr, "libnet_init() failed: %s", errbuf);
exit(EXIT_FAILURE);
}
src_ip = 0;
dst_ip = 0;
while ((c = getopt(argc, argv, "d:s:p:")) != EOF)
{
switch (c)
{
/*
* We expect the input to be of the form `ip.ip.ip.ip.port`. We
* point cp to the last dot of the IP address/port string and
* then seperate them with a NULL byte. The optarg now points to
* just the IP address, and cp points to the port.
*/
case 'd':
if ((dst_ip = libnet_name2addr4(l, optarg, LIBNET_RESOLVE)) == -1)
{
fprintf(stderr, "Bad destination IP address: %s\n", optarg);
goto bad;
}
break;
case 's':
if ((src_ip = libnet_name2addr4(l, optarg, LIBNET_RESOLVE)) == -1)
{
fprintf(stderr, "Bad source IP address: %s\n", optarg);
goto bad;
}
break;
case 'p':
filename = optarg;
break;
default:
fprintf(stderr, "unkown option [%s]: bye bye\n", optarg);
goto bad;
}
}
if (!src_ip || !dst_ip)
{
usage(argv[0]);
exit(EXIT_FAILURE);
}
/*
* build payload
*
* 2 bytes string 1 byte string 1 byte
* ------------------------------------------------
* | Opcode | Filename | 0 | Mode | 0 |
* ------------------------------------------------
*
*/
payload_s = 2 + strlen(filename) + 1 + strlen(mode) + 1;
payload = malloc(sizeof(char)*payload_s);
if (!payload)
{
fprintf(stderr, "malloc error for payload\n");
goto bad;
}
memset(payload, 0, payload_s);
payload[1] = 1; /* opcode - GET */
memcpy(payload + 2, filename, strlen(filename));
memcpy(payload + 2 + strlen(filename) + 1 , mode, strlen(mode));
/*
* Build pblocks
*/
udp = libnet_build_udp(
0x1234, /* source port */
69, /* destination port */
LIBNET_UDP_H + payload_s, /* packet length */
0, /* checksum */
payload, /* payload */
payload_s, /* payload size */
l, /* libnet handle */
0); /* libnet id */
if (udp == -1)
{
fprintf(stderr, "Can't build UDP header: %s\n", libnet_geterror(l));
goto bad;
}
ip = libnet_build_ipv4(
LIBNET_IPV4_H + LIBNET_UDP_H + payload_s, /* length - dont forget the UDP's payload */
0, /* TOS */
0x4242, /* IP ID */
0, /* IP Frag */
0x42, /* TTL */
IPPROTO_UDP, /* protocol */
0, /* checksum */
src_ip, /* source IP */
dst_ip, /* destination IP */
NULL, /* payload (already in UDP) */
0, /* payload size */
l, /* libnet handle */
0); /* libnet id */
if (ip == -1)
{
fprintf(stderr, "Can't build IP header: %s\n", libnet_geterror(l));
goto bad;
}
/*
* Write it to the wire.
*/
c = libnet_write(l);
if (c == -1)
{
fprintf(stderr, "Write error: %s\n", libnet_geterror(l));
goto bad;
}
else
{
fprintf(stderr, "Wrote %d byte TFTP packet; check the wire.\n", c);
}
libnet_destroy(l);
free(payload);
return (EXIT_SUCCESS);
bad:
libnet_destroy(l);
free(payload);
return (EXIT_FAILURE);
}
void
usage(char *name)
{
fprintf(stderr,
"usage: %s -s source_ip -d destination_ip"
" [-p payload] [-t|u|i] \n",
name);
}
/* EOF */
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