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osscan.cc
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/***************************************************************************
* osscan.cc -- Routines used for OS detection via TCP/IP fingerprinting. *
* For more information on how this works in Nmap, see my paper at *
* http://www.insecure.org/osdetect/ *
* *
***********************IMPORTANT NMAP LICENSE TERMS************************
* *
* The Nmap Security Scanner is (C) 1996-2006 Insecure.Com LLC. Nmap is *
* also a registered trademark of Insecure.Com LLC. This program is free *
* software; you may redistribute and/or modify it under the terms of the *
* GNU General Public License as published by the Free Software *
* Foundation; Version 2 with the clarifications and exceptions described *
* below. This guarantees your right to use, modify, and redistribute *
* this software under certain conditions. If you wish to embed Nmap *
* technology into proprietary software, we sell alternative licenses *
* (contact sales@insecure.com). Dozens of software vendors already *
* license Nmap technology such as host discovery, port scanning, OS *
* detection, and version detection. *
* *
* Note that the GPL places important restrictions on "derived works", yet *
* it does not provide a detailed definition of that term. To avoid *
* misunderstandings, we consider an application to constitute a *
* "derivative work" for the purpose of this license if it does any of the *
* following: *
* o Integrates source code from Nmap *
* o Reads or includes Nmap copyrighted data files, such as *
* nmap-os-fingerprints or nmap-service-probes. *
* o Executes Nmap and parses the results (as opposed to typical shell or *
* execution-menu apps, which simply display raw Nmap output and so are *
* not derivative works.) *
* o Integrates/includes/aggregates Nmap into a proprietary executable *
* installer, such as those produced by InstallShield. *
* o Links to a library or executes a program that does any of the above *
* *
* The term "Nmap" should be taken to also include any portions or derived *
* works of Nmap. This list is not exclusive, but is just meant to *
* clarify our interpretation of derived works with some common examples. *
* These restrictions only apply when you actually redistribute Nmap. For *
* example, nothing stops you from writing and selling a proprietary *
* front-end to Nmap. Just distribute it by itself, and point people to *
* http://insecure.org/nmap/ to download Nmap. *
* *
* We don't consider these to be added restrictions on top of the GPL, but *
* just a clarification of how we interpret "derived works" as it applies *
* to our GPL-licensed Nmap product. This is similar to the way Linus *
* Torvalds has announced his interpretation of how "derived works" *
* applies to Linux kernel modules. Our interpretation refers only to *
* Nmap - we don't speak for any other GPL products. *
* *
* If you have any questions about the GPL licensing restrictions on using *
* Nmap in non-GPL works, we would be happy to help. As mentioned above, *
* we also offer alternative license to integrate Nmap into proprietary *
* applications and appliances. These contracts have been sold to dozens *
* of software vendors, and generally include a perpetual license as well *
* as providing for priority support and updates as well as helping to *
* fund the continued development of Nmap technology. Please email *
* sales@insecure.com for further information. *
* *
* As a special exception to the GPL terms, Insecure.Com LLC grants *
* permission to link the code of this program with any version of the *
* OpenSSL library which is distributed under a license identical to that *
* listed in the included Copying.OpenSSL file, and distribute linked *
* combinations including the two. You must obey the GNU GPL in all *
* respects for all of the code used other than OpenSSL. If you modify *
* this file, you may extend this exception to your version of the file, *
* but you are not obligated to do so. *
* *
* If you received these files with a written license agreement or *
* contract stating terms other than the terms above, then that *
* alternative license agreement takes precedence over these comments. *
* *
* Source is provided to this software because we believe users have a *
* right to know exactly what a program is going to do before they run it. *
* This also allows you to audit the software for security holes (none *
* have been found so far). *
* *
* Source code also allows you to port Nmap to new platforms, fix bugs, *
* and add new features. You are highly encouraged to send your changes *
* to fyodor@insecure.org for possible incorporation into the main *
* distribution. By sending these changes to Fyodor or one the *
* Insecure.Org development mailing lists, it is assumed that you are *
* offering Fyodor and Insecure.Com LLC the unlimited, non-exclusive right *
* to reuse, modify, and relicense the code. Nmap will always be *
* available Open Source, but this is important because the inability to *
* relicense code has caused devastating problems for other Free Software *
* projects (such as KDE and NASM). We also occasionally relicense the *
* code to third parties as discussed above. If you wish to specify *
* special license conditions of your contributions, just say so when you *
* send them. *
* *
* This program is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details at *
* http://www.gnu.org/copyleft/gpl.html , or in the COPYING file included *
* with Nmap. *
* *
***************************************************************************/
/* $Id$ */
#include "osscan.h"
#include "timing.h"
#include "NmapOps.h"
#include "nmap_tty.h"
#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
# include <sys/time.h>
# else
# include <time.h>
# endif
#endif
extern NmapOps o;
/* Note that a sport of 0 really will (try to) use zero as the source
port rather than choosing a random one */
static struct udpprobeinfo *send_closedudp_probe(int sd, struct eth_nfo *eth,
const struct in_addr *victim,
u16 sport, u16 dport) {
static struct udpprobeinfo upi;
static int myttl = 0;
static u8 patternbyte = 0;
static u16 id = 0;
u8 packet[328]; /* 20 IP hdr + 8 UDP hdr + 300 data */
struct ip *ip = (struct ip *) packet;
struct udp_hdr *udp = (struct udp_hdr *) (packet + sizeof(struct ip));
struct in_addr *source;
int datalen = 300;
unsigned char *data = packet + 28;
unsigned short realcheck; /* the REAL checksum */
int res;
int decoy;
if (!patternbyte) patternbyte = (get_random_uint() % 60) + 65;
memset(data, patternbyte, datalen);
while(!id) id = get_random_uint();
/* check that required fields are there and not too silly */
if ( !victim || !dport || (!eth && sd < 0)) {
fprintf(stderr, "send_closedudp_probe: One or more of your parameters suck!\n");
return NULL;
}
if (!myttl) myttl = (time(NULL) % 14) + 51;
for(decoy=0; decoy < o.numdecoys; decoy++) {
source = &o.decoys[decoy];
memset((char *) packet, 0, sizeof(struct ip) + sizeof(struct udp_hdr));
udp->uh_sport = htons(sport);
udp->uh_dport = htons(dport);
udp->uh_ulen = htons(8 + datalen);
/* OK, now we should be able to compute a valid checksum */
realcheck = magic_tcpudp_cksum(source, victim, IPPROTO_UDP,
sizeof(struct udp_hdr) + datalen, (char *) udp);
#if STUPID_SOLARIS_CHECKSUM_BUG
udp->uh_sum = sizeof(struct udp_hdr) + datalen;
#else
udp->uh_sum = realcheck;
#endif
if ( o.badsum ) {
udp->uh_sum--;
if (udp->uh_sum == 0) udp->uh_sum = 0xffff; // UDP checksum=0 means no checksum
}
/* Now for the ip header */
ip->ip_v = 4;
ip->ip_hl = 5;
ip->ip_len = htons(sizeof(struct ip) + sizeof(struct udp_hdr) + datalen);
ip->ip_id = id;
ip->ip_ttl = myttl;
ip->ip_p = IPPROTO_UDP;
ip->ip_src.s_addr = source->s_addr;
ip->ip_dst.s_addr= victim->s_addr;
upi.ipck = in_cksum((unsigned short *)ip, sizeof(struct ip));
#if HAVE_IP_IP_SUM
ip->ip_sum = upi.ipck;
#endif
/* OK, now if this is the real she-bang (ie not a decoy) then
we stick all the inph0 in our upi */
if (decoy == o.decoyturn) {
upi.iptl = 28 + datalen;
upi.ipid = id;
upi.sport = sport;
upi.dport = dport;
upi.udpck = realcheck;
upi.udplen = 8 + datalen;
upi.patternbyte = patternbyte;
upi.target.s_addr = ip->ip_dst.s_addr;
}
if ((res = send_ip_packet(sd, eth, packet, ntohs(ip->ip_len))) == -1)
{
perror("send_ip_packet in send_closedupd_probe");
return NULL;
}
}
return &upi;
}
static struct AVal *fingerprint_iptcppacket(struct ip *ip, int mss, u32 syn) {
struct AVal *AVs;
int length;
int opcode;
u16 tmpshort;
char *p,*q;
struct tcp_hdr *tcp = ((struct tcp_hdr *) (((char *) ip) + 4 * ip->ip_hl));
AVs = (struct AVal *) safe_malloc(6 * sizeof(struct AVal));
/* Link them together */
AVs[0].next = &AVs[1];
AVs[1].next = &AVs[2];
AVs[2].next = &AVs[3];
AVs[3].next = &AVs[4];
AVs[4].next = &AVs[5];
AVs[5].next = NULL;
/* First we give the "response" flag to say we did actually receive
a packet -- this way we won't match a template with Resp=N */
AVs[0].attribute = "Resp";
strcpy(AVs[0].value, "Y");
/* Next we check whether the Don't Fragment bit is set */
AVs[1].attribute = "DF";
if(ntohs(ip->ip_off) & 0x4000) {
strcpy(AVs[1].value,"Y");
} else strcpy(AVs[1].value, "N");
/* Now we do the TCP Window size */
AVs[2].attribute = "W";
sprintf(AVs[2].value, "%hX", ntohs(tcp->th_win));
/* Time for the ACK, the codes are:
S = same as syn
S++ = syn + 1
O = other
*/
AVs[3].attribute = "ACK";
if (ntohl(tcp->th_ack) == syn + 1)
strcpy(AVs[3].value, "S++");
else if (ntohl(tcp->th_ack) == syn)
strcpy(AVs[3].value, "S");
else strcpy(AVs[3].value, "O");
/* Now time for the flags ... they must be in this order:
B = Bogus (64, not a real TCP flag)
U = Urgent
A = Acknowledgement
P = Push
R = Reset
S = Synchronize
F = Final
*/
AVs[4].attribute = "Flags";
p = AVs[4].value;
if (tcp->th_flags & TH_ECE) *p++ = 'B';
if (tcp->th_flags & TH_URG) *p++ = 'U';
if (tcp->th_flags & TH_ACK) *p++ = 'A';
if (tcp->th_flags & TH_PUSH) *p++ = 'P';
if (tcp->th_flags & TH_RST) *p++ = 'R';
if (tcp->th_flags & TH_SYN) *p++ = 'S';
if (tcp->th_flags & TH_FIN) *p++ = 'F';
*p++ = '\0';
/* Now for the TCP options ... */
AVs[5].attribute = "Ops";
p = AVs[5].value;
/* Partly swiped from /usr/src/linux/net/ipv4/tcp_input.c in Linux kernel */
length = (tcp->th_off * 4) - sizeof(struct tcp_hdr);
q = ((char *)tcp) + sizeof(struct tcp_hdr);
while(length > 0 &&
((p - AVs[5].value) < (int) (sizeof(AVs[5].value) - 3))) {
opcode=*q++;
length--;
if (!opcode) {
*p++ = 'L'; /* End of List */
break;
} else if (opcode == 1) {
*p++ = 'N'; /* No Op */
} else if (opcode == 2) {
*p++ = 'M'; /* MSS */
q++;
memcpy(&tmpshort, q, 2);
if(ntohs(tmpshort) == mss)
*p++ = 'E'; /* Echoed */
q += 2;
length -= 3;
} else if (opcode == 3) { /* Window Scale */
*p++ = 'W';
q += 2;
length -= 2;
} else if (opcode == 8) { /* Timestamp */
*p++ = 'T';
q += 9;
length -= 9;
}
}
*p++ = '\0';
return AVs;
}
static struct AVal *fingerprint_portunreach(struct ip *ip, struct udpprobeinfo *upi) {
struct icmp *icmp;
struct ip *ip2;
int numtests = 10;
unsigned short checksum;
unsigned short *checksumptr;
struct udp_hdr *udp;
struct AVal *AVs;
int i;
int current_testno = 0;
unsigned char *datastart, *dataend;
/* The very first thing we do is make sure this is the correct
response */
if (ip->ip_p != IPPROTO_ICMP) {
error("fingerprint_portunreach handed a non-ICMP packet!");
return NULL;
}
if (ip->ip_src.s_addr != upi->target.s_addr)
return NULL; /* Not the person we sent to */
icmp = ((struct icmp *) (((char *) ip) + 4 * ip->ip_hl));
if (icmp->icmp_type != 3 || icmp->icmp_code != 3)
return NULL; /* Not a port unreachable */
ip2 = (struct ip*) ((char *)icmp + 8);
udp = (struct udp_hdr *) ((char *)ip2 + 20);
/* The ports better match as well ... */
if (ntohs(udp->uh_sport) != upi->sport || ntohs(udp->uh_dport) != upi->dport) {
return NULL;
}
/* Create the Avals */
AVs = (struct AVal *) safe_zalloc(numtests * sizeof(struct AVal));
/* Link them together */
for(i=0; i < numtests - 1; i++)
AVs[i].next = &AVs[i+1];
/* First of all, if we got this far the response was yes */
AVs[current_testno].attribute = "Resp";
strcpy(AVs[current_testno].value, "Y");
current_testno++;
/* Now let us do an easy one, Don't fragment */
AVs[current_testno].attribute = "DF";
if(ntohs(ip->ip_off) & 0x4000) {
strcpy(AVs[current_testno].value,"Y");
} else strcpy(AVs[current_testno].value, "N");
current_testno++;
/* Now lets do TOS of the response (note, I've never seen this be
useful */
AVs[current_testno].attribute = "TOS";
sprintf(AVs[current_testno].value, "%hX", ip->ip_tos);
current_testno++;
/* Now we look at the IP datagram length that was returned, some
machines send more of the original packet back than others */
AVs[current_testno].attribute = "IPLEN";
sprintf(AVs[current_testno].value, "%hX", ntohs(ip->ip_len));
current_testno++;
/* OK, lets check the returned IP length, some systems @$@ this
up */
AVs[current_testno].attribute = "RIPTL";
sprintf(AVs[current_testno].value, "%hX", ntohs(ip2->ip_len));
current_testno++;
/* This next test doesn't work on Solaris because the lamers
overwrite our ip_id */
#if !defined(SOLARIS) && !defined(SUNOS) && !defined(IRIX) && !defined(HPUX)
/* Now lets see how they treated the ID we sent ... */
AVs[current_testno].attribute = "RID";
if (ntohs(ip2->ip_id) == 0)
strcpy(AVs[current_testno].value, "0");
else if (ip2->ip_id == upi->ipid)
strcpy(AVs[current_testno].value, "E"); /* The "expected" value */
else strcpy(AVs[current_testno].value, "F"); /* They fucked it up */
current_testno++;
#endif
/* Let us see if the IP checksum we got back computes */
AVs[current_testno].attribute = "RIPCK";
/* Thanks to some machines not having struct ip member ip_sum we
have to go with this BS */
checksumptr = (unsigned short *) ((char *) ip2 + 10);
checksum = *checksumptr;
if (checksum == 0)
strcpy(AVs[current_testno].value, "0");
else {
*checksumptr = 0;
if (in_cksum((unsigned short *)ip2, 20) == checksum) {
strcpy(AVs[current_testno].value, "E"); /* The "expected" value */
} else {
strcpy(AVs[current_testno].value, "F"); /* They fucked it up */
}
*checksumptr = checksum;
}
current_testno++;
/* UDP checksum */
AVs[current_testno].attribute = "UCK";
if (udp->uh_sum == 0)
strcpy(AVs[current_testno].value, "0");
else if (udp->uh_sum == upi->udpck)
strcpy(AVs[current_testno].value, "E"); /* The "expected" value */
else strcpy(AVs[current_testno].value, "F"); /* They fucked it up */
current_testno++;
/* UDP length ... */
AVs[current_testno].attribute = "ULEN";
sprintf(AVs[current_testno].value, "%hX", ntohs(udp->uh_ulen));
current_testno++;
/* Finally we ensure the data is OK */
datastart = ((unsigned char *)udp) + 8;
dataend = (unsigned char *) ip + ntohs(ip->ip_len);
while(datastart < dataend) {
if (*datastart != upi->patternbyte) break;
datastart++;
}
AVs[current_testno].attribute = "DAT";
if (datastart < dataend)
strcpy(AVs[current_testno].value, "F"); /* They fucked it up */
else
strcpy(AVs[current_testno].value, "E");
AVs[current_testno].next = NULL;
return AVs;
}
static FingerPrint *get_fingerprint(Target *target, struct seq_info *si) {
FingerPrint *FP = NULL, *FPtmp = NULL;
FingerPrint *FPtests[9];
struct AVal *seq_AVs;
u16 lastipid=0; /* For catching duplicate packets */
int last;
u32 timestamp = 0; /* TCP timestamp we receive back */
struct ip *ip;
struct tcp_hdr *tcp;
struct icmp *icmp;
struct timeval t1,t2;
int i;
pcap_t *pd = NULL;
int rawsd;
int tries = 0;
int newcatches;
int current_port = 0;
int testsleft;
int testno;
int timeout;
int avnum;
unsigned int sequence_base;
unsigned long openport;
unsigned int bytes;
unsigned int closedport = 31337;
Port *tport = NULL;
char filter[512];
double seq_inc_sum = 0;
unsigned int seq_avg_inc = 0;
struct udpprobeinfo *upi = NULL;
u32 seq_gcd = 1;
u32 seq_diffs[NUM_SEQ_SAMPLES];
u32 ts_diffs[NUM_SEQ_SAMPLES];
unsigned long time_usec_diffs[NUM_SEQ_SAMPLES];
struct timeval seq_send_times[NUM_SEQ_SAMPLES];
int ossofttimeout, oshardtimeout;
int seq_packets_sent = 0;
int seq_response_num; /* response # for sequencing */
double avg_ts_hz = 0.0; /* Avg. amount that timestamps incr. each second */
struct link_header linkhdr;
struct eth_nfo eth;
struct eth_nfo *ethptr; // for passing to send_ functions
if (target->timedOut(NULL))
return NULL;
/* The seqs must start out as zero for the si struct */
memset(si->seqs, 0, sizeof(si->seqs));
si->ipid_seqclass = IPID_SEQ_UNKNOWN;
si->ts_seqclass = TS_SEQ_UNKNOWN;
si->lastboot = 0;
/* Init our fingerprint tests to each be NULL */
memset(FPtests, 0, sizeof(FPtests));
get_random_bytes(&sequence_base, sizeof(unsigned int));
if ((o.sendpref & PACKET_SEND_ETH) && target->ifType() == devt_ethernet) {
memcpy(eth.srcmac, target->SrcMACAddress(), 6);
memcpy(eth.dstmac, target->NextHopMACAddress(), 6);
eth.ethsd = eth_open_cached(target->deviceName());
if (eth.ethsd == NULL)
fatal("%s: Failed to open ethernet device (%s)", __FUNCTION__, target->deviceName());
rawsd = -1;
ethptr = ð
} else {
/* Init our raw socket */
if ((rawsd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0 )
pfatal("socket troubles in get_fingerprint");
unblock_socket(rawsd);
broadcast_socket(rawsd);
#ifndef WIN32
sethdrinclude(rawsd);
#endif
ethptr = NULL;
eth.ethsd = NULL;
}
/* Now for the pcap opening nonsense ... */
/* Note that the snaplen is 152 = 64 byte max IPhdr + 24 byte max link_layer
* header + 64 byte max TCP header. Had to up it for UDP test
*/
ossofttimeout = MAX(200000, target->to.timeout);
oshardtimeout = MAX(500000, 5 * target->to.timeout);
pd = my_pcap_open_live(target->deviceName(), /*650*/ 8192, (o.spoofsource)? 1 : 0, (ossofttimeout + 500)/ 1000);
if (o.debugging > 1)
log_write(LOG_STDOUT, "Wait time is %dms\n", (ossofttimeout +500)/1000);
snprintf(filter, sizeof(filter), "dst host %s and (icmp or (tcp and src host %s))", inet_ntoa(target->v4source()), target->targetipstr());
set_pcap_filter(target->deviceName(), pd, filter);
target->osscan_performed = 1; /* Let Nmap know that we did try an OS scan */
/* Lets find an open port to use */
openport = (unsigned long) -1;
target->FPR1->osscan_opentcpport = -1;
target->FPR1->osscan_closedtcpport = -1;
target->FPR1->osscan_closedudpport = -1;
tport = NULL;
if ((tport = target->ports.nextPort(NULL, IPPROTO_TCP, PORT_OPEN))) {
openport = tport->portno;
target->FPR1->osscan_opentcpport = tport->portno;
}
/* Now we should find a closed port */
if ((tport = target->ports.nextPort(NULL, IPPROTO_TCP, PORT_CLOSED))) {
closedport = tport->portno;
target->FPR1->osscan_closedtcpport = tport->portno;
} else if ((tport = target->ports.nextPort(NULL, IPPROTO_TCP, PORT_UNFILTERED))) {
/* Well, we will settle for unfiltered */
closedport = tport->portno;
} else {
closedport = (get_random_uint() % 14781) + 30000;
}
if (o.verbose && openport != (unsigned long) -1)
log_write(LOG_STDOUT, "For OSScan assuming port %lu is open, %d is closed, and neither are firewalled\n", openport, closedport);
current_port = o.magic_port + NUM_SEQ_SAMPLES +1;
/* Now lets do the NULL packet technique */
testsleft = (openport == (unsigned long) -1)? 4 : 8;
FPtmp = NULL;
tries = 0;
do {
newcatches = 0;
if (openport != (unsigned long) -1) {
/* Test 1 */
if (!FPtests[1]) {
if (o.scan_delay) enforce_scan_delay(NULL);
send_tcp_raw_decoys(rawsd, ethptr, target->v4hostip(), o.ttl, false, NULL, 0,
current_port, openport, sequence_base, 0, 0,
TH_ECE|TH_SYN, 0, 0, (u8 *) "\003\003\012\001\002\004\001\011\010\012\077\077\077\077\000\000\000\000\000\000", 20, NULL, 0);
}
/* Test 2 */
if (!FPtests[2]) {
if (o.scan_delay) enforce_scan_delay(NULL);
send_tcp_raw_decoys(rawsd, ethptr, target->v4hostip(), o.ttl, false, NULL, 0,
current_port +1, openport, sequence_base, 0, 0,
0, 0, 0, (u8 *) "\003\003\012\001\002\004\001\011\010\012\077\077\077\077\000\000\000\000\000\000" , 20, NULL, 0);
}
/* Test 3 */
if (!FPtests[3]) {
if (o.scan_delay) enforce_scan_delay(NULL);
send_tcp_raw_decoys(rawsd, ethptr, target->v4hostip(), o.ttl, false, NULL, 0,
current_port +2, openport, sequence_base, 0, 0,
TH_SYN|TH_FIN|TH_URG|TH_PUSH, 0, 0, (u8 *) "\003\003\012\001\002\004\001\011\010\012\077\077\077\077\000\000\000\000\000\000" , 20, NULL, 0);
}
/* Test 4 */
if (!FPtests[4]) {
if (o.scan_delay) enforce_scan_delay(NULL);
send_tcp_raw_decoys(rawsd, ethptr, target->v4hostip(), o.ttl, false, NULL, 0,
current_port +3, openport, sequence_base, 0, 0,
TH_ACK, 0, 0, (u8 *) "\003\003\012\001\002\004\001\011\010\012\077\077\077\077\000\000\000\000\000\000" , 20, NULL, 0);
}
}
/* Test 5 */
if (!FPtests[5]) {
if (o.scan_delay) enforce_scan_delay(NULL);
send_tcp_raw_decoys(rawsd, ethptr, target->v4hostip(), o.ttl, false, NULL, 0,
current_port +4, closedport, sequence_base, 0, 0,
TH_SYN, 0, 0, (u8 *) "\003\003\012\001\002\004\001\011\010\012\077\077\077\077\000\000\000\000\000\000" , 20, NULL, 0);
}
/* Test 6 */
if (!FPtests[6]) {
if (o.scan_delay) enforce_scan_delay(NULL);
send_tcp_raw_decoys(rawsd, ethptr, target->v4hostip(), o.ttl, false, NULL, 0,
current_port +5, closedport, sequence_base, 0, 0,
TH_ACK, 0, 0, (u8 *) "\003\003\012\001\002\004\001\011\010\012\077\077\077\077\000\000\000\000\000\000" , 20, NULL, 0);
}
/* Test 7 */
if (!FPtests[7]) {
if (o.scan_delay) enforce_scan_delay(NULL);
send_tcp_raw_decoys(rawsd, ethptr, target->v4hostip(), o.ttl, false, NULL, 0,
current_port +6, closedport, sequence_base, 0, 0,
TH_FIN|TH_PUSH|TH_URG, 0, 0, (u8 *) "\003\003\012\001\002\004\001\011\010\012\077\077\077\077\000\000\000\000\000\000" , 20, NULL, 0);
}
/* Test 8 */
if (!FPtests[8]) {
if (o.scan_delay) enforce_scan_delay(NULL);
upi = send_closedudp_probe(rawsd, ethptr, target->v4hostip(), o.magic_port, closedport);
}
gettimeofday(&t1, NULL);
timeout = 0;
/* Insure we haven't overrun our allotted time ... */
if (target->timedOut(&t1))
goto osscan_timedout;
while(( ip = (struct ip*) readip_pcap(pd, &bytes, oshardtimeout, NULL, &linkhdr)) && !timeout) {
gettimeofday(&t2, NULL);
if (TIMEVAL_SUBTRACT(t2,t1) > oshardtimeout) {
timeout = 1;
}
if (target->timedOut(&t2))
goto osscan_timedout;
if (bytes < (4 * ip->ip_hl) + 4U || bytes < 20)
continue;
setTargetMACIfAvailable(target, &linkhdr, ip, 0);
if (ip->ip_p == IPPROTO_TCP) {
tcp = ((struct tcp_hdr *) (((char *) ip) + 4 * ip->ip_hl));
testno = ntohs(tcp->th_dport) - current_port + 1;
if (testno <= 0 || testno > 7)
continue;
if (o.debugging > 1)
log_write(LOG_STDOUT, "Got packet for test number %d\n", testno);
if (FPtests[testno]) continue;
testsleft--;
newcatches++;
FPtests[testno] = (FingerPrint *) safe_zalloc(sizeof(FingerPrint));
FPtests[testno]->results = fingerprint_iptcppacket(ip, 265, sequence_base);
FPtests[testno]->name = (testno == 1)? "T1" : (testno == 2)? "T2" : (testno == 3)? "T3" : (testno == 4)? "T4" : (testno == 5)? "T5" : (testno == 6)? "T6" : (testno == 7)? "T7" : "PU";
} else if (ip->ip_p == IPPROTO_ICMP) {
icmp = ((struct icmp *) (((char *) ip) + 4 * ip->ip_hl));
/* It must be a destination port unreachable */
if (icmp->icmp_type != 3 || icmp->icmp_code != 3) {
/* This ain't no stinking port unreachable! */
continue;
}
if (bytes < (unsigned int) ntohs(ip->ip_len)) {
error("We only got %d bytes out of %d on our ICMP port unreachable packet, skipping", bytes, ntohs(ip->ip_len));
continue;
}
if (FPtests[8]) continue;
FPtests[8] = (FingerPrint *) safe_zalloc(sizeof(FingerPrint));
FPtests[8]->results = fingerprint_portunreach(ip, upi);
if (FPtests[8]->results) {
FPtests[8]->name = "PU";
testsleft--;
newcatches++;
} else {
free(FPtests[8]);
FPtests[8] = NULL;
}
}
if (testsleft == 0)
break;
}
} while ( testsleft > 0 && (tries++ < 5 && (newcatches || tries == 1)));
si->responses = 0;
timeout = 0;
gettimeofday(&t1,NULL);
/* Next we send our initial NUM_SEQ_SAMPLES SYN packets */
if (openport != (unsigned long) -1) {
seq_packets_sent = 0;
while (seq_packets_sent < NUM_SEQ_SAMPLES) {
if (o.scan_delay) enforce_scan_delay(NULL);
if (seq_packets_sent > 0) {
gettimeofday(&t1, NULL);
int remaining_us = 110000 - TIMEVAL_SUBTRACT(t1, seq_send_times[seq_packets_sent - 1]);
if (remaining_us > 0) {
/* Need to spend at least .5 seconds in sending all packets to
reliably detect 2HZ timestamp sequencing */
usleep(remaining_us);
}
}
send_tcp_raw_decoys(rawsd, ethptr, target->v4hostip(), o.ttl, false, NULL, 0,
o.magic_port + seq_packets_sent + 1,
openport,
sequence_base + seq_packets_sent + 1, 0, 0,
TH_SYN, 0, 0, (u8 *) "\003\003\012\001\002\004\001\011\010\012\077\077\077\077\000\000\000\000\000\000" , 20, NULL, 0);
gettimeofday(&seq_send_times[seq_packets_sent], NULL);
t1 = seq_send_times[seq_packets_sent];
seq_packets_sent++;
/* Now we collect the replies */
while(si->responses < seq_packets_sent && !timeout) {
if (seq_packets_sent == NUM_SEQ_SAMPLES)
ip = (struct ip*) readip_pcap(pd, &bytes, oshardtimeout, NULL, &linkhdr);
else ip = (struct ip*) readip_pcap(pd, &bytes, 10, NULL, &linkhdr);
gettimeofday(&t2, NULL);
/* error("DEBUG: got a response (len=%d):\n", bytes); */
/* lamont_hdump((unsigned char *) ip, bytes); */
/* Insure we haven't overrun our allotted time ... */
if (target->timedOut(&t2))
goto osscan_timedout;
if (!ip) {
if (seq_packets_sent < NUM_SEQ_SAMPLES)
break;
if (TIMEVAL_SUBTRACT(t2,t1) > ossofttimeout)
timeout = 1;
continue;
} else if (TIMEVAL_SUBTRACT(t2,t1) > oshardtimeout) {
timeout = 1;
}
if (lastipid != 0 && ip->ip_id == lastipid) {
/* Probably a duplicate -- this happens sometimes when scanning localhost */
continue;
}
lastipid = ip->ip_id;
if (bytes < (4 * ip->ip_hl) + 4U || bytes < 20)
continue;
setTargetMACIfAvailable(target, &linkhdr, ip, 0);
if (ip->ip_p == IPPROTO_TCP) {
/* readtcppacket((char *) ip, ntohs(ip->ip_len)); */
tcp = ((struct tcp_hdr *) (((char *) ip) + 4 * ip->ip_hl));
if (ntohs(tcp->th_dport) < o.magic_port ||
ntohs(tcp->th_dport) - o.magic_port > NUM_SEQ_SAMPLES ||
ntohs(tcp->th_sport) != openport) {
continue;
}
if ((tcp->th_flags & TH_RST)) {
/* readtcppacket((char *) ip, ntohs(ip->ip_len));*/
if (si->responses == 0) {
fprintf(stderr, "WARNING: RST from port %lu -- is this port really open?\n", openport);
/* We used to quit in this case, but left-overs from a SYN
scan or lame-ass TCP wrappers can cause this! */
}
continue;
} else if ((tcp->th_flags & (TH_SYN|TH_ACK)) == (TH_SYN|TH_ACK)) {
/* error("DEBUG: response is SYN|ACK to port %hu\n", ntohs(tcp->th_dport)); */
/*readtcppacket((char *)ip, ntohs(ip->ip_len));*/
/* We use the ACK value to match up our sent with rcv'd packets */
seq_response_num = (ntohl(tcp->th_ack) - 2 -
sequence_base);
if (seq_response_num < 0 || seq_response_num >= seq_packets_sent) {
/* BzzT! Value out of range */
if (o.debugging) {
error("Unable to associate os scan response with sent packet (received ack: %lX; sequence base: %lX. Packet:", (unsigned long) ntohl(tcp->th_ack), (unsigned long) sequence_base);
readtcppacket((unsigned char *)ip,ntohs(ip->ip_len));
}
seq_response_num = si->responses;
}
if (si->seqs[seq_response_num] == 0) {
/* New response found! */
si->responses++;
si->seqs[seq_response_num] = ntohl(tcp->th_seq); /* TCP ISN */
si->ipids[seq_response_num] = ntohs(ip->ip_id);
if ((gettcpopt_ts(tcp, ×tamp, NULL) == 0))
si->ts_seqclass = TS_SEQ_UNSUPPORTED;
else {
if (timestamp == 0) {
si->ts_seqclass = TS_SEQ_ZERO;
}
}
si->timestamps[seq_response_num] = timestamp;
/* printf("Response #%d -- ipid=%hu ts=%i\n", seq_response_num, ntohs(ip->ip_id), timestamp); */
if (si->responses > 1) {
seq_diffs[si->responses-2] = MOD_DIFF(ntohl(tcp->th_seq), si->seqs[si->responses-2]);
}
}
}
}
}
}
/* Now we make sure there are no gaps in our response array ... */
for(i=0, si->responses=0; i < seq_packets_sent; i++) {
if (si->seqs[i] != 0) /* We found a good one */ {
if (si->responses < i) {
si->seqs[si->responses] = si->seqs[i];
si->ipids[si->responses] = si->ipids[i];
si->timestamps[si->responses] = si->timestamps[i];
seq_send_times[si->responses] = seq_send_times[i];
}
if (si->responses > 0) {
seq_diffs[si->responses - 1] = MOD_DIFF(si->seqs[si->responses], si->seqs[si->responses - 1]);
ts_diffs[si->responses - 1] = MOD_DIFF(si->timestamps[si->responses], si->timestamps[si->responses - 1]);
time_usec_diffs[si->responses - 1] = TIMEVAL_SUBTRACT(seq_send_times[si->responses], seq_send_times[si->responses - 1]);
if (!time_usec_diffs[si->responses - 1]) time_usec_diffs[si->responses - 1]++; /* We divide by this later */
/* printf("MOD_DIFF_USHORT(%hu, %hu) == %hu\n", si->ipids[si->responses], si->ipids[si->responses - 1], MOD_DIFF_USHORT(si->ipids[si->responses], si->ipids[si->responses - 1])); */
}
si->responses++;
} /* Otherwise nothing good in this slot to copy */
}
si->ipid_seqclass = ipid_sequence(si->responses, si->ipids,
islocalhost(target->v4hostip()));
/* Now we look at TCP Timestamp sequence prediction */
/* Battle plan:
1) Compute average increments per second, and variance in incr. per second
2) If any are 0, set to constant
3) If variance is high, set to random incr. [ skip for now ]
4) if ~10/second, set to appropriate thing
5) Same with ~100/sec
*/
if (si->ts_seqclass == TS_SEQ_UNKNOWN && si->responses >= 2) {
avg_ts_hz = 0.0;
for(i=0; i < si->responses - 1; i++) {
double dhz;
dhz = (double) ts_diffs[i] / (time_usec_diffs[i] / 1000000.0);
/* printf("ts incremented by %d in %li usec -- %fHZ\n", ts_diffs[i], time_usec_diffs[i], dhz); */
avg_ts_hz += dhz / ( si->responses - 1);
}
if (o.debugging)
printf("The avg TCP TS HZ is: %f\n", avg_ts_hz);
if (avg_ts_hz > 0 && avg_ts_hz < 3.9) { /* relatively wide range because sampling time so short and frequency so slow */
si->ts_seqclass = TS_SEQ_2HZ;
si->lastboot = seq_send_times[0].tv_sec - (si->timestamps[0] / 2);
}
else if (avg_ts_hz > 85 && avg_ts_hz < 115) {
si->ts_seqclass = TS_SEQ_100HZ;
si->lastboot = seq_send_times[0].tv_sec - (si->timestamps[0] / 100);
}
else if (avg_ts_hz > 900 && avg_ts_hz < 1100) {
si->ts_seqclass = TS_SEQ_1000HZ;
si->lastboot = seq_send_times[0].tv_sec - (si->timestamps[0] / 1000);
}
if (si->lastboot && (seq_send_times[0].tv_sec - si->lastboot > 63072000))
{
/* Up 2 years? Perhaps, but they're probably lying. */
if (o.debugging) {
error("Ignoring claimed uptime of %lu days",
(seq_send_times[0].tv_sec - si->lastboot) / 86400);
}
si->lastboot = 0;
}
}
/* Time to look at the TCP ISN predictability */
if (si->responses >= 4 && o.scan_delay <= 1000) {
seq_gcd = gcd_n_uint(si->responses -1, seq_diffs);
/* printf("The GCD is %u\n", seq_gcd);*/
if (seq_gcd) {
for(i=0; i < si->responses - 1; i++)
seq_diffs[i] /= seq_gcd;
for(i=0; i < si->responses - 1; i++) {
if (MOD_DIFF(si->seqs[i+1],si->seqs[i]) > 50000000) {
si->seqclass = SEQ_TR;
si->index = 9999999;
/* printf("Target is a TR box\n");*/
break;
}
seq_avg_inc += seq_diffs[i];
}
}
if (seq_gcd == 0) {
si->seqclass = SEQ_CONSTANT;
si->index = 0;
} else if (seq_gcd % 64000 == 0) {
si->seqclass = SEQ_64K;
/* printf("Target is a 64K box\n");*/
si->index = 1;
} else if (seq_gcd % 800 == 0) {
si->seqclass = SEQ_i800;
/* printf("Target is a i800 box\n");*/
si->index = 10;
} else if (si->seqclass == SEQ_UNKNOWN) {
seq_avg_inc = (unsigned int) ((0.5) + seq_avg_inc / (si->responses - 1));
/* printf("seq_avg_inc=%u\n", seq_avg_inc);*/
for(i=0; i < si->responses -1; i++) {
/* printf("The difference is %u\n", seq_diffs[i]);
printf("Adding %u^2=%e", MOD_DIFF(seq_diffs[i], seq_avg_inc), pow(MOD_DIFF(seq_diffs[i], seq_avg_inc), 2));*/
/* pow() seems F#@!#$!ed up on some Linux systems so I will
not use it for now
seq_inc_sum += pow(MOD_DIFF(seq_diffs[i], seq_avg_inc), 2);
*/
seq_inc_sum += ((double)(MOD_DIFF(seq_diffs[i], seq_avg_inc)) * ((double)MOD_DIFF(seq_diffs[i], seq_avg_inc)));
/* seq_inc_sum += pow(MOD_DIFF(seq_diffs[i], seq_avg_inc), 2);*/
}
/* printf("The sequence sum is %e\n", seq_inc_sum);*/
seq_inc_sum /= (si->responses - 1);
si->index = (unsigned int) (0.5 + sqrt(seq_inc_sum));
/* printf("The sequence index is %d\n", si->index);*/
if (si->index < 75) {
si->seqclass = SEQ_TD;
/* printf("Target is a Micro$oft style time dependant box\n");*/
}
else {
si->seqclass = SEQ_RI;
/* printf("Target is a random incremental box\n");*/
}
}
FPtests[0] = (FingerPrint *) safe_zalloc(sizeof(FingerPrint));
FPtests[0]->name = "TSeq";
seq_AVs = (struct AVal *) safe_zalloc(sizeof(struct AVal) * 5);
FPtests[0]->results = seq_AVs;
avnum = 0;
seq_AVs[avnum].attribute = "Class";
switch(si->seqclass) {
case SEQ_CONSTANT:
strcpy(seq_AVs[avnum].value, "C");
seq_AVs[avnum].next = &seq_AVs[avnum+1]; avnum++;
seq_AVs[avnum].attribute= "Val";
sprintf(seq_AVs[avnum].value, "%X", si->seqs[0]);
break;
case SEQ_64K:
strcpy(seq_AVs[avnum].value, "64K");
break;
case SEQ_i800:
strcpy(seq_AVs[avnum].value, "i800");
break;
case SEQ_TD:
strcpy(seq_AVs[avnum].value, "TD");
seq_AVs[avnum].next = &seq_AVs[avnum+1]; avnum++;
seq_AVs[avnum].attribute= "gcd";
sprintf(seq_AVs[avnum].value, "%X", seq_gcd);
seq_AVs[avnum].next = &seq_AVs[avnum+1]; avnum++;
seq_AVs[avnum].attribute="SI";
sprintf(seq_AVs[avnum].value, "%X", si->index);
break;
case SEQ_RI:
strcpy(seq_AVs[avnum].value, "RI");
seq_AVs[avnum].next = &seq_AVs[avnum+1]; avnum++;
seq_AVs[avnum].attribute= "gcd";
sprintf(seq_AVs[avnum].value, "%X", seq_gcd);
seq_AVs[avnum].next = &seq_AVs[avnum+1]; avnum++;
seq_AVs[avnum].attribute="SI";
sprintf(seq_AVs[avnum].value, "%X", si->index);
break;
case SEQ_TR:
strcpy(seq_AVs[avnum].value, "TR");
break;
}