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scan_engine_raw.cc
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/***************************************************************************
* scan_engine_raw.cc -- includes helper functions for scan_engine.cc that *
* are related to port scanning using raw (IP, Ethernet) packets. *
* *
***********************IMPORTANT NMAP LICENSE TERMS************************
* *
* The Nmap Security Scanner is (C) 1996-2015 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 ("GPL"), BUT ONLY WITH ALL OF THE CLARIFICATIONS *
* AND EXCEPTIONS DESCRIBED HEREIN. 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 [email protected]). Dozens of software *
* vendors already license Nmap technology such as host discovery, port *
* scanning, OS detection, version detection, and the Nmap Scripting *
* Engine. *
* *
* Note that the GPL places important restrictions on "derivative works", *
* yet it does not provide a detailed definition of that term. To avoid *
* misunderstandings, we interpret that term as broadly as copyright law *
* allows. For example, we consider an application to constitute a *
* derivative work for the purpose of this license if it does any of the *
* following with any software or content covered by this license *
* ("Covered Software"): *
* *
* o Integrates source code from Covered Software. *
* *
* o Reads or includes copyrighted data files, such as Nmap's nmap-os-db *
* or nmap-service-probes. *
* *
* o Is designed specifically to execute Covered Software and parse the *
* results (as opposed to typical shell or execution-menu apps, which will *
* execute anything you tell them to). *
* *
* o Includes Covered Software in a proprietary executable installer. The *
* installers produced by InstallShield are an example of this. Including *
* Nmap with other software in compressed or archival form does not *
* trigger this provision, provided appropriate open source decompression *
* or de-archiving software is widely available for no charge. For the *
* purposes of this license, an installer is considered to include Covered *
* Software even if it actually retrieves a copy of Covered Software from *
* another source during runtime (such as by downloading it from the *
* Internet). *
* *
* o Links (statically or dynamically) to a library which does any of the *
* above. *
* *
* o Executes a helper program, module, or script to do any of the above. *
* *
* This list is not exclusive, but is meant to clarify our interpretation *
* of derived works with some common examples. Other people may interpret *
* the plain GPL differently, so we consider this a special exception to *
* the GPL that we apply to Covered Software. Works which meet any of *
* these conditions must conform to all of the terms of this license, *
* particularly including the GPL Section 3 requirements of providing *
* source code and allowing free redistribution of the work as a whole. *
* *
* As another 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 docs/licenses/OpenSSL.txt file, and distribute *
* linked combinations including the two. *
* *
* Any redistribution of Covered Software, including any derived works, *
* must obey and carry forward all of the terms of this license, including *
* obeying all GPL rules and restrictions. For example, source code of *
* the whole work must be provided and free redistribution must be *
* allowed. All GPL references to "this License", are to be treated as *
* including the terms and conditions of this license text as well. *
* *
* Because this license imposes special exceptions to the GPL, Covered *
* Work may not be combined (even as part of a larger work) with plain GPL *
* software. The terms, conditions, and exceptions of this license must *
* be included as well. This license is incompatible with some other open *
* source licenses as well. In some cases we can relicense portions of *
* Nmap or grant special permissions to use it in other open source *
* software. Please contact [email protected] with any such requests. *
* Similarly, we don't incorporate incompatible open source software into *
* Covered Software without special permission from the copyright holders. *
* *
* If you have any questions about the licensing restrictions on using *
* Nmap in other works, are 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. They also fund the *
* continued development of Nmap. Please email [email protected] for further *
* information. *
* *
* If you have received a written license agreement or contract for *
* Covered Software stating terms other than these, you may choose to use *
* and redistribute Covered Software under those terms instead of these. *
* *
* 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. *
* *
* 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 the [email protected] mailing list for possible incorporation into the *
* main distribution. By sending these changes to Fyodor or one of the *
* Insecure.Org development mailing lists, or checking them into the Nmap *
* source code repository, it is understood (unless you specify otherwise) *
* that you are offering the Nmap Project (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 Nmap *
* license file for more details (it's in a COPYING file included with *
* Nmap, and also available from https://svn.nmap.org/nmap/COPYING) *
* *
***************************************************************************/
/* $Id$ */
#include "nmap_error.h"
#include "NmapOps.h"
#include "payload.h"
#include "scan_engine_raw.h"
#include "struct_ip.h"
#include "tcpip.h"
#include "utils.h"
#include <string>
extern NmapOps o;
/* Pass an arp packet, including ethernet header. Must be 42bytes */
void UltraProbe::setARP(u8 *arppkt, u32 arplen) {
type = UP_ARP;
mypspec.type = PS_ARP;
return;
}
void UltraProbe::setND(u8 *ndpkt, u32 ndlen) {
type = UP_ND;
mypspec.type = PS_ND;
return;
}
/* Sets this UltraProbe as type UP_IP and creates & initializes the
internal IPProbe. The relevant probespec is necessary for setIP
because pspec.type is ambiguous with just the ippacket (e.g. a
tcp packet could be PS_PROTO or PS_TCP). */
void UltraProbe::setIP(u8 *ippacket, u32 len, const probespec *pspec) {
struct ip *ip = (struct ip *) ippacket;
struct tcp_hdr *tcp = NULL;
struct udp_hdr *udp = NULL;
struct sctp_hdr *sctp = NULL;
struct ppkt *icmp = NULL;
const void *data;
u8 hdr;
type = UP_IP;
if (ip->ip_v == 4) {
data = ipv4_get_data(ip, &len);
assert(data != NULL);
assert(len + ip->ip_hl * 4 == (u32) ntohs(ip->ip_len));
probes.IP.ipid = ntohs(ip->ip_id);
hdr = ip->ip_p;
} else if (ip->ip_v == 6) {
const struct ip6_hdr *ip6 = (struct ip6_hdr *) ippacket;
data = ipv6_get_data_any(ip6, &len, &hdr);
assert(data != NULL);
assert(len == (u32) ntohs(ip6->ip6_plen));
probes.IP.ipid = ntohl(ip6->ip6_flow & IP6_FLOWLABEL_MASK);
hdr = ip6->ip6_nxt;
} else {
fatal("Bogus packet passed to %s -- only IP packets allowed", __func__);
}
if (hdr == IPPROTO_TCP) {
assert(len >= 20);
tcp = (struct tcp_hdr *) data;
probes.IP.pd.tcp.sport = ntohs(tcp->th_sport);
probes.IP.pd.tcp.seq = ntohl(tcp->th_seq);
} else if (hdr == IPPROTO_UDP) {
assert(len >= 8);
udp = (struct udp_hdr *) data;
probes.IP.pd.udp.sport = ntohs(udp->uh_sport);
} else if (hdr == IPPROTO_SCTP) {
assert(len >= 12);
sctp = (struct sctp_hdr *) data;
probes.IP.pd.sctp.sport = ntohs(sctp->sh_sport);
probes.IP.pd.sctp.vtag = ntohl(sctp->sh_vtag);
} else if (hdr == IPPROTO_ICMP || hdr == IPPROTO_ICMPV6) {
icmp = (struct ppkt *) data;
probes.IP.pd.icmp.ident = ntohs(icmp->id);
}
mypspec = *pspec;
return;
}
u16 UltraProbe::icmpid() const {
assert(mypspec.proto == IPPROTO_ICMP || mypspec.proto == IPPROTO_ICMPV6);
return probes.IP.pd.icmp.ident;
}
u32 UltraProbe::tcpseq() const {
if (mypspec.proto == IPPROTO_TCP)
return probes.IP.pd.tcp.seq;
else
fatal("Bogus seq number request to %s -- type is %s", __func__,
pspectype2ascii(mypspec.type));
return 0; // Unreached
}
u32 UltraProbe::sctpvtag() const {
assert(mypspec.proto == IPPROTO_SCTP);
return probes.IP.pd.sctp.vtag;
}
/* We encode per-probe information like the tryno and pingseq in the source
port, for protocols that use ports. (Except when o.magic_port_set is
true--then we honor the requested source port.) The tryno and pingseq are
encoded as offsets from base_port, a base source port number (see
sport_encode and sport_decode). To avoid interpreting a late response from a
previous invocation of ultra_scan as a response for the same port in the
current invocation, we increase base_port by a healthy amount designed to be
greater than any offset likely to be used by a probe, each time ultra_scan is
run.
If we don't increase the base port, then there is the risk of something like
the following happening:
1. Nmap sends an ICMP echo and a TCP ACK probe to port 80 for host discovery.
2. Nmap receives an ICMP echo reply and marks the host up.
3. Nmap sends a TCP SYN probe to port 80 for port scanning.
4. Nmap finally receives a delayed TCP RST in response to its earlier ACK
probe, and wrongly marks port 80 as closed. */
static u16 base_port;
/* Clamp n to the range [min, max) in a modular fashion. */
static int mod_offset(int n, int min, int max) {
assert(min < max);
n = (n - min) % (max - min);
if (n < 0)
n += max - min;
return n + min;
}
/* Change base_port to a new number in a safe port range that is unlikely to
conflict with nearby past or future invocations of ultra_scan. */
void increment_base_port() {
static bool initialized = false;
if (!initialized) {
base_port = mod_offset(get_random_uint(), 33000, 65536 - 256);
initialized = true;
} else {
base_port = mod_offset(base_port + 256, 33000, 65536 - 256);
}
}
/* The try number or ping sequence number can be encoded into a TCP SEQ or ACK
field. This returns a 32-bit number which encodes both of these values along
with a simple checksum. Decoding is done by seq32_decode. */
static u32 seq32_encode(UltraScanInfo *USI, unsigned int trynum,
unsigned int pingseq) {
u32 seq;
u16 nfo;
/* We'll let trynum and pingseq each be 8 bits. */
nfo = (pingseq << 8) + trynum;
/* Mirror the data to ensure it is reconstructed correctly. */
seq = (nfo << 16) + nfo;
/* Obfuscate it a little */
seq = seq ^ USI->seqmask;
return seq;
}
/* Undoes seq32_encode. This extracts a try number and a port number from a
32-bit value. Returns true if the checksum is correct, false otherwise. */
static bool seq32_decode(const UltraScanInfo *USI, u32 seq,
unsigned int *trynum, unsigned int *pingseq) {
if (trynum)
*trynum = 0;
if (pingseq)
*pingseq = 0;
/* Undo the mask xor. */
seq = seq ^ USI->seqmask;
/* Check that both sides are the same. */
if ((seq >> 16) != (seq & 0xFFFF))
return false;
if (trynum)
*trynum = seq & 0xFF;
if (pingseq)
*pingseq = (seq & 0xFF00) >> 8;
return true;
}
/* The try number or ping sequence number can be encoded in the source port
number. This returns a new port number that contains a try number or ping
sequence number encoded into the given port number. trynum and pingseq may
not both be non-zero. Decoding is done by sport_decode. */
static u16 sport_encode(UltraScanInfo *USI, u16 base_portno, unsigned int trynum,
unsigned int pingseq) {
u16 portno;
/* trynum and pingseq both being non-zero is not currently supported. */
assert(trynum == 0 || pingseq == 0);
portno = base_portno;
if (pingseq > 0) {
/* Encode the pingseq. trynum = 0. */
portno += USI->perf.tryno_cap + pingseq;
} else {
/* Encode the trynum. pingseq = 0. */
portno += trynum;
}
return portno;
}
/* Undoes sport_encode. This extracts a try number and ping sequence number from
a port number given a "base" port number (the one given to
sport_encode). Returns true if the decoded values seem reasonable, false
otherwise. */
static bool sport_decode(const UltraScanInfo *USI, u16 base_portno, u16 portno,
unsigned int *trynum, unsigned int *pingseq) {
unsigned int t;
t = portno - base_portno;
if (t > USI->perf.tryno_cap + 256) {
return false;
} else if (t > USI->perf.tryno_cap) {
/* The ping sequence number was encoded. */
if (pingseq)
*pingseq = t - USI->perf.tryno_cap;
if (trynum)
*trynum = 0;
} else {
/* The try number was encoded. */
if (pingseq)
*pingseq = 0;
if (trynum)
*trynum = t;
}
return true;
}
static bool icmp_probe_match(const UltraScanInfo *USI, const UltraProbe *probe,
const struct ppkt *ping,
const struct sockaddr_storage *target_src,
const struct sockaddr_storage *src,
const struct sockaddr_storage *dst,
u8 proto,
u32 ipid) {
/* Check if it is ICMP or ICMPV6. */
if (probe->protocol() != IPPROTO_ICMPV6 && probe->protocol() != IPPROTO_ICMP)
return false;
/* Ensure the connection info matches. */
if (sockaddr_storage_cmp(target_src, dst) != 0)
return false;
/* Don't match a timestamp request with an echo reply, for example. */
if (proto == IPPROTO_ICMP &&
((ping->type == 0 && probe->pspec()->pd.icmp.type != 8) ||
(ping->type == 14 && probe->pspec()->pd.icmp.type != 13) ||
(ping->type == 18 && probe->pspec()->pd.icmp.type != 17)))
return false;
if (proto == IPPROTO_ICMPV6 &&
(ping->type == 129 && probe->pspec()->pd.icmpv6.type != 128))
return false;
/* Sometimes we get false results when scanning localhost with
-p- because we scan localhost with src port = dst port and
see our outgoing packet and think it is a response. */
if (probe->dport() == probe->sport() &&
sockaddr_storage_cmp(src, dst) == 0 &&
probe->ipid() == ipid)
return false; /* We saw the packet we ourselves sent */
/* Check that the randomly-generated ping ident matches. */
if (ntohs(ping->id) != probe->icmpid())
return false;
return true;
}
static bool tcp_probe_match(const UltraScanInfo *USI, const UltraProbe *probe,
const HostScanStats *hss, const struct tcp_hdr *tcp,
const struct sockaddr_storage *src, const struct sockaddr_storage *dst,
u32 ipid) {
const struct probespec_tcpdata *probedata;
struct sockaddr_storage srcaddr;
size_t srcaddr_len;
unsigned int tryno, pingseq;
bool goodseq;
if (probe->protocol() != IPPROTO_TCP)
return false;
srcaddr_len = sizeof(srcaddr);
hss->target->SourceSockAddr(&srcaddr, &srcaddr_len);
/* Ensure the connection info matches. */
if (probe->dport() != ntohs(tcp->th_sport)
|| probe->sport() != ntohs(tcp->th_dport)
|| sockaddr_storage_cmp(&srcaddr, dst) != 0)
return false;
tryno = 0;
pingseq = 0;
if (o.magic_port_set) {
/* We are looking to recover the tryno and pingseq of the probe, which are
encoded in the ACK field for probes with the ACK flag set and in the SEQ
field for all other probes. According to RFC 793, section 3.9, under
"SEGMENT ARRIVES", it's supposed to work like this: If our probe had ACK
set, our ACK number is reflected in the response's SEQ field. If our
probe had SYN or FIN set (and not ACK), then our SEQ is one less than the
returned ACK value because SYN and FIN consume a sequence number (section
3.3). Otherwise, our SEQ is the returned ACK.
However, nmap-os-db shows that these assumptions can't be relied on, so
we try all three possibilities for each probe. */
goodseq = seq32_decode(USI, ntohl(tcp->th_ack) - 1, &tryno, &pingseq)
|| seq32_decode(USI, ntohl(tcp->th_ack), &tryno, &pingseq)
|| seq32_decode(USI, ntohl(tcp->th_seq), &tryno, &pingseq);
} else {
/* Get the values from the destination port (our source port). */
sport_decode(USI, base_port, ntohs(tcp->th_dport), &tryno, &pingseq);
goodseq = true;
}
if (!goodseq) {
/* Connection info matches, but there was a nonsensical tryno/pingseq. */
if (o.debugging)
log_write(LOG_PLAIN, "Bad Sequence number from host %s.\n", inet_ntop_ez(src, sizeof(*src)));
return false;
}
/* Make sure that trynum and pingseq match the values in the probe. */
if (!probe->check_tryno_pingseq(tryno, pingseq))
return false;
/* Make sure we are matching up the right kind of probe, otherwise just the
ports, address, tryno, and pingseq can be ambiguous, between a SYN and an
ACK probe during a -PS80 -PA80 scan for example. A SYN/ACK can only be
matched to a SYN probe. */
probedata = &probe->pspec()->pd.tcp;
if ((tcp->th_flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)
&& !(probedata->flags & TH_SYN)) {
return false;
}
/* Sometimes we get false results when scanning localhost with -p- because we
scan localhost with src port = dst port and see our outgoing packet and
think it is a response. */
if (probe->dport() == probe->sport()
&& sockaddr_storage_cmp(src, dst) == 0
&& probe->ipid() == ipid)
return false;
return true;
}
/* Tries to get one *good* (finishes a probe) pcap response to a host discovery
(ping) probe by the (absolute) time given in stime. Even if stime is now,
try an ultra-quick pcap read just in case. Returns true if a "good" result
was found, false if it timed out instead. */
int get_ping_pcap_result(UltraScanInfo *USI, struct timeval *stime) {
bool goodone = false;
bool timedout = false;
bool adjust_timing = true;
struct timeval rcvdtime;
struct link_header linkhdr;
struct ip *ip_tmp;
unsigned int bytes;
struct ppkt *ping;
long to_usec;
HostScanStats *hss = NULL;
std::list<UltraProbe *>::iterator probeI;
UltraProbe *probe = NULL;
unsigned int trynum = 0;
int newstate = HOST_UNKNOWN;
unsigned int probenum;
unsigned int listsz;
reason_t current_reason = ER_NORESPONSE;
struct sockaddr_storage target_src, target_dst;
size_t ss_len;
const void *data = NULL;
unsigned int datalen;
struct abstract_ip_hdr hdr;
do {
to_usec = TIMEVAL_SUBTRACT(*stime, USI->now);
if (to_usec < 2000)
to_usec = 2000;
ip_tmp = (struct ip *) readip_pcap(USI->pd, &bytes, to_usec, &rcvdtime,
&linkhdr, true);
gettimeofday(&USI->now, NULL);
if (!ip_tmp) {
if (TIMEVAL_SUBTRACT(*stime, USI->now) < 0) {
timedout = true;
break;
} else {
continue;
}
}
if (TIMEVAL_SUBTRACT(USI->now, *stime) > 200000) {
/* While packets are still being received, I'll be generous and give
an extra 1/5 sec. But we have to draw the line somewhere */
timedout = true;
}
/* OK, we got a packet. Most packet validity tests are taken care
* of in readip_pcap, so this is simple
*/
datalen = bytes;
data = ip_get_data(ip_tmp, &datalen, &hdr);
if (data == NULL)
continue;
/* First check if it is ICMP, TCP, or UDP */
if (hdr.proto == IPPROTO_ICMP || hdr.proto == IPPROTO_ICMPV6) {
/* if it is our response */
ping = (struct ppkt *) data;
if (bytes < 8U) {
if (!ip_tmp->ip_off)
error("Supposed ping packet is only %d bytes long!", bytes);
continue;
}
current_reason = icmp_to_reason(hdr.proto, ping->type, ping->code);
/* Echo reply, Timestamp reply, or Address Mask Reply. RFCs 792 and 950. */
/* ICMPv6 Echo reply */
if (USI->ptech.rawicmpscan
&& ((hdr.proto == IPPROTO_ICMP && (ping->type == 0 || ping->type == 14 || ping->type == 18))
|| (hdr.proto == IPPROTO_ICMPV6 && ping->type == 129))) {
hss = USI->findHost(&hdr.src);
if (!hss)
continue; // Not from a host that interests us
setTargetMACIfAvailable(hss->target, &linkhdr, &hdr.src, 0);
probeI = hss->probes_outstanding.end();
listsz = hss->num_probes_outstanding();
ss_len = sizeof(target_src);
hss->target->SourceSockAddr(&target_src, &ss_len);
/* A check for weird_responses is needed here. This is not currently
possible because we don't have a good way to look up the original
target of an ICMP probe based on the response. (massping encoded an
array index in the ICMP sequence, which won't work here.) Once we've
found the host that sent the probe that elicited the response, the
test for weird_responses is
if (sending_host->v4host().s_addr != ip->ip_src.s_addr)
hss->target->weird_responses++;
(That is, the target that sent the probe is not the same one that
sent the response.)
*/
goodone = false;
/* Find the probe that provoked this response. */
for (probenum = 0; probenum < listsz && !goodone; probenum++) {
probeI--;
probe = *probeI;
if (!icmp_probe_match(USI, probe, ping, &target_src, &hdr.src, &hdr.dst, hdr.proto, hdr.ipid))
continue;
goodone = true;
newstate = HOST_UP;
if (o.debugging)
log_write(LOG_STDOUT, "We got a ping packet back from %s: id = %d seq = %d checksum = %d\n", inet_ntop_ez(&hdr.src, sizeof(hdr.src)), ping->id, ping->seq, ping->checksum);
}
}
// For ICMP, the reply of TCP/UDP/ICMP packets can be Destination unreachable, source quench, or time exceeded
/* For ICMPv6, the reply of TCP/UDP/ICMPV6 packets can be Destination Unreachable,
* Packet Too Big, Time Exceeded and Parameter Problem.*/
else if ((hdr.proto == IPPROTO_ICMP && (ping->type == 3 || ping->type
== 4 || ping->type == 11))
|| (hdr.proto == IPPROTO_ICMPV6 && (ping->type == 1 || ping->type == 2
|| ping->type == 3 || ping->type == 4))) {
const void *encaps_data;
unsigned int encaps_len;
struct abstract_ip_hdr encaps_hdr;
if (datalen < 8)
continue;
encaps_len = datalen - 8;
encaps_data = ip_get_data((char *) data + 8, &encaps_len, &encaps_hdr);
if (encaps_data == NULL ||
/* UDP hdr, or TCP hdr up to seq #, or SCTP hdr up to vtag */
((USI->tcp_scan || USI->udp_scan || USI->sctp_scan) && encaps_len < 8)
/* prot scan has no headers coming back, so we don't reserve the
8 extra bytes */
) {
if (o.debugging)
error("Received short ICMP or ICMPv6 packet (%u bytes)", datalen);
continue;
}
/* Bail out early if possible. */
if (!USI->ptech.rawprotoscan) {
if (encaps_hdr.proto == IPPROTO_ICMP && !USI->ptech.rawicmpscan)
continue;
if (encaps_hdr.proto == IPPROTO_ICMPV6 && !USI->ptech.rawicmpscan)
continue;
if (encaps_hdr.proto == IPPROTO_TCP && !USI->ptech.rawtcpscan)
continue;
if (encaps_hdr.proto == IPPROTO_UDP && !USI->ptech.rawudpscan)
continue;
if (encaps_hdr.proto == IPPROTO_SCTP && !USI->ptech.rawsctpscan)
continue;
}
hss = USI->findHost(&encaps_hdr.dst);
if (!hss)
continue; // Not referring to a host that interests us
setTargetMACIfAvailable(hss->target, &linkhdr, &encaps_hdr.dst, 0);
probeI = hss->probes_outstanding.end();
listsz = hss->num_probes_outstanding();
ss_len = sizeof(target_src);
hss->target->SourceSockAddr(&target_src, &ss_len);
ss_len = sizeof(target_dst);
hss->target->TargetSockAddr(&target_dst, &ss_len);
/* Find the probe that provoked this response. */
for (probenum = 0; probenum < listsz; probenum++) {
probeI--;
probe = *probeI;
if (probe->protocol() != encaps_hdr.proto ||
sockaddr_storage_cmp(&target_src, &hdr.dst) != 0 ||
sockaddr_storage_cmp(&target_src, &encaps_hdr.src) != 0 ||
sockaddr_storage_cmp(&target_dst, &encaps_hdr.dst) != 0 ||
((probe->protocol() == IPPROTO_ICMP || probe->protocol() == IPPROTO_ICMPV6) &&
ntohs(ping->id) != probe->icmpid()))
continue;
if ((encaps_hdr.proto == IPPROTO_ICMP || encaps_hdr.proto == IPPROTO_ICMPV6)
&& USI->ptech.rawicmpscan) {
/* The response was based on a ping packet we sent */
} else if (encaps_hdr.proto == IPPROTO_TCP && USI->ptech.rawtcpscan) {
struct tcp_hdr *tcp = (struct tcp_hdr *) encaps_data;
if (probe->dport() != ntohs(tcp->th_dport) ||
probe->sport() != ntohs(tcp->th_sport) ||
probe->tcpseq() != ntohl(tcp->th_seq))
continue;
} else if (encaps_hdr.proto == IPPROTO_UDP && USI->ptech.rawudpscan) {
struct udp_hdr *udp = (struct udp_hdr *) encaps_data;
if (probe->dport() != ntohs(udp->uh_dport) ||
probe->sport() != ntohs(udp->uh_sport))
continue;
} else if (encaps_hdr.proto == IPPROTO_SCTP && USI->ptech.rawsctpscan) {
struct sctp_hdr *sctp = (struct sctp_hdr *) encaps_data;
if (probe->dport() != ntohs(sctp->sh_dport) ||
probe->sport() != ntohs(sctp->sh_sport) ||
probe->sctpvtag() != ntohl(sctp->sh_vtag))
continue;
} else if (USI->ptech.rawprotoscan) {
/* Success; we already know that the address and protocol match. */
} else {
assert(0);
}
/* If we made it this far, we found it. We don't yet know if it's
going to change a host state (goodone) or not. */
break;
}
/* Did we fail to find a probe? */
if (probenum >= listsz)
continue;
if ((hdr.proto == IPPROTO_ICMP && ping->type == 3)
|| (hdr.proto == IPPROTO_ICMPV6 && ping->type == 1)) {
/* Destination unreachable. */
if (sockaddr_storage_cmp(&target_dst, &hdr.src) == 0) {
/* The ICMP or ICMPv6 error came directly from the target, so it's up. */
goodone = true;
newstate = HOST_UP;
} else {
goodone = true;
newstate = HOST_DOWN;
}
if (o.debugging) {
if ((hdr.proto == IPPROTO_ICMP && ping->code == 3)
|| (hdr.proto == IPPROTO_ICMPV6 && ping->code == 4))
log_write(LOG_STDOUT, "Got port unreachable for %s\n", hss->target->targetipstr());
else
log_write(LOG_STDOUT, "Got destination unreachable for %s\n", hss->target->targetipstr());
}
} else if ((hdr.proto == IPPROTO_ICMP && ping->type == 11)
|| (hdr.proto == IPPROTO_ICMPV6 && ping->type == 3)) {
if (o.debugging)
log_write(LOG_STDOUT, "Got Time Exceeded for %s\n", hss->target->targetipstr());
goodone = 1;
newstate = HOST_DOWN;
/* I don't want anything to do with timing this. */
adjust_timing = false;
} else if (hdr.proto == IPPROTO_ICMP && ping->type == 4) {
if (o.debugging)
log_write(LOG_STDOUT, "Got ICMP source quench\n");
usleep(50000);
} else if (hdr.proto == IPPROTO_ICMPV6 && ping->type == 4) {
if (o.debugging)
log_write(LOG_STDOUT, "Got ICMPv6 Parameter Problem\n");
} else if (hdr.proto == IPPROTO_ICMP) {
if (o.debugging) {
log_write(LOG_STDOUT, "Got ICMP message type %d code %d\n",
ping->type, ping->code);
}
} else if (hdr.proto == IPPROTO_ICMPV6) {
if (o.debugging)
log_write(LOG_STDOUT, "Got ICMPv6 message type %d code %d\n",
ping->type, ping->code);
}
}
} else if (hdr.proto == IPPROTO_TCP && USI->ptech.rawtcpscan) {
struct tcp_hdr *tcp = (struct tcp_hdr *) data;
/* Check that the packet has useful flags. */
if (!(tcp->th_flags & TH_RST)
&& ((tcp->th_flags & (TH_SYN | TH_ACK)) != (TH_SYN | TH_ACK)))
continue;
/* Now ensure this host is even in the incomplete list */
hss = USI->findHost(&hdr.src);
if (!hss)
continue; // Not from a host that interests us
setTargetMACIfAvailable(hss->target, &linkhdr, &hdr.src, 0);
probeI = hss->probes_outstanding.end();
listsz = hss->num_probes_outstanding();
goodone = false;
/* Find the probe that provoked this response. */
for (probenum = 0; probenum < listsz && !goodone; probenum++) {
probeI--;
probe = *probeI;
if (!tcp_probe_match(USI, probe, hss, tcp, &hdr.src, &hdr.dst, hdr.ipid))
continue;
goodone = true;
newstate = HOST_UP;
/* Fill out the reason. */
if (o.pingtype & PINGTYPE_TCP_USE_SYN) {
if (tcp->th_flags & TH_RST) {
current_reason = ER_RESETPEER;
} else if ((tcp->th_flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) {
current_reason = ER_SYNACK;
}
} else if (o.pingtype & PINGTYPE_TCP_USE_ACK) {
if (tcp->th_flags & TH_RST)
current_reason = ER_RESETPEER;
}
if (o.debugging)
log_write(LOG_STDOUT, "We got a TCP ping packet back from %s port %hu (trynum = %d)\n", inet_ntop_ez(&hdr.src, sizeof(hdr.src)), ntohs(tcp->th_sport), trynum);
}
} else if (hdr.proto == IPPROTO_UDP && USI->ptech.rawudpscan) {
struct udp_hdr *udp = (struct udp_hdr *) data;
/* Search for this host on the incomplete list */
hss = USI->findHost(&hdr.src);
if (!hss)
continue; // Not from a host that interests us
probeI = hss->probes_outstanding.end();
listsz = hss->num_probes_outstanding();
goodone = false;
ss_len = sizeof(target_src);
hss->target->SourceSockAddr(&target_src, &ss_len);
for (probenum = 0; probenum < listsz && !goodone; probenum++) {
probeI--;
probe = *probeI;
if (o.af() != AF_INET || probe->protocol() != IPPROTO_UDP)
continue;
/* Ensure the connection info matches. */
if (probe->dport() != ntohs(udp->uh_sport) ||
probe->sport() != ntohs(udp->uh_dport) ||
sockaddr_storage_cmp(&target_src, &hdr.dst) != 0)
continue;
/* Replace this with a call to probe_check_trynum_pingseq or similar. */
if (o.magic_port_set) {
trynum = probe->tryno;
} else {
sport_decode(USI, base_port, ntohs(udp->uh_dport), &trynum, NULL);
}
/* Sometimes we get false results when scanning localhost with
-p- because we scan localhost with src port = dst port and
see our outgoing packet and think it is a response. */
if (probe->dport() == probe->sport() &&
sockaddr_storage_cmp(&hdr.src, &hdr.dst) == 0 &&
probe->ipid() == hdr.ipid)
continue; /* We saw the packet we ourselves sent */
goodone = true;
newstate = HOST_UP;
current_reason = ER_UDPRESPONSE;
if (o.debugging)
log_write(LOG_STDOUT, "In response to UDP-ping, we got UDP packet back from %s port %hu (trynum = %d)\n", inet_ntop_ez(&hdr.src, sizeof(hdr.src)), htons(udp->uh_sport), trynum);
}
} else if (hdr.proto == IPPROTO_SCTP && USI->ptech.rawsctpscan) {
struct sctp_hdr *sctp = (struct sctp_hdr *) data;
struct dnet_sctp_chunkhdr *chunk =
(struct dnet_sctp_chunkhdr *) ((u8 *) sctp + 12);
/* Search for this host on the incomplete list */
hss = USI->findHost(&hdr.src);
if (!hss)
continue; // Not from a host that interests us
probeI = hss->probes_outstanding.end();
listsz = hss->num_probes_outstanding();
goodone = false;
ss_len = sizeof(target_dst);
hss->target->SourceSockAddr(&target_src, &ss_len);
for (probenum = 0; probenum < listsz && !goodone; probenum++) {
probeI--;
probe = *probeI;
if (o.af() != AF_INET || probe->protocol() != IPPROTO_SCTP)
continue;
/* Ensure the connection info matches. */
if (probe->dport() != ntohs(sctp->sh_sport) ||
probe->sport() != ntohs(sctp->sh_dport) ||
sockaddr_storage_cmp(&target_src, &hdr.dst) != 0)
continue;
/* Sometimes we get false results when scanning localhost with
-p- because we scan localhost with src port = dst port and
see our outgoing packet and think it is a response. */
if (probe->dport() == probe->sport() &&
sockaddr_storage_cmp(&hdr.src, &hdr.dst) == 0 &&
probe->ipid() == hdr.ipid)
continue; /* We saw the packet we ourselves sent */
goodone = true;
newstate = HOST_UP;
if (chunk->sch_type == SCTP_INIT_ACK) {
current_reason = ER_INITACK;
} else if (chunk->sch_type == SCTP_ABORT) {
current_reason = ER_ABORT;
} else {
current_reason = ER_UNKNOWN;
if (o.debugging)
log_write(LOG_STDOUT, "Received scan response with unexpected SCTP chunks: n/a");
}
}
} else if (!USI->ptech.rawprotoscan) {
if (o.debugging > 2)
error("Received packet with protocol %d; ignoring.", hdr.proto);
}
/* Check for a protocol reply */
if (!goodone && USI->ptech.rawprotoscan) {
hss = USI->findHost(&hdr.src);
if (!hss)
continue;
setTargetMACIfAvailable(hss->target, &linkhdr, &hdr.src, 0);
probeI = hss->probes_outstanding.end();
listsz = hss->num_probes_outstanding();
goodone = false;
for (probenum = 0; probenum < listsz && !goodone; probenum++) {
probeI--;
probe = *probeI;
if (probe->protocol() == hdr.proto) {
/* if this is our probe we sent to localhost, then it doesn't count! */
if (sockaddr_storage_cmp(&hdr.src, &hdr.dst) == 0 &&
probe->ipid() == hdr.ipid)
break;
newstate = HOST_UP;
current_reason = ER_PROTORESPONSE;
goodone = true;
}
}
}
} while (!goodone && !timedout);
if (goodone && newstate != HOST_UNKNOWN) {
struct sockaddr_storage target_dst;
size_t ss_len;
ss_len = sizeof(target_dst);
hss->target->TargetSockAddr(&target_dst, &ss_len);
if (probe->isPing())
ultrascan_ping_update(USI, hss, probeI, &USI->now, adjust_timing);
else {
ultrascan_host_probe_update(USI, hss, probeI, newstate, &rcvdtime, adjust_timing);
/* If the host is up, we can forget our other probes. */
if (newstate == HOST_UP)
hss->destroyAllOutstandingProbes();
if (newstate == HOST_UP && data)
setTargetMACIfAvailable(hss->target, &linkhdr, &hdr.src, 0);
hss->target->reason.reason_id = current_reason;
hss->target->reason.ttl = hdr.ttl;
if (sockaddr_storage_cmp(&hdr.src, &target_dst) != 0) {
hss->target->reason.set_ip_addr(&hdr.src);
}
}
}
return 0;
}
/* Initiate libpcap or some other sniffer as appropriate to be able to catch
responses */
void begin_sniffer(UltraScanInfo *USI, std::vector<Target *> &Targets) {
std::string pcap_filter = "";
/* 20 IPv6 addresses is max (45 byte addy + 14 (" or src host ")) * 20 == 1180 */
std::string dst_hosts = "";
unsigned int len = 0;
unsigned int targetno;
bool doIndividual = Targets.size() <= 20; // Don't bother IP limits if scanning huge # of hosts
if (doIndividual) {
for (targetno = 0; targetno < Targets.size(); targetno++) {
dst_hosts += (targetno == 0) ? "" : " or ";
dst_hosts += "src host ";
dst_hosts += Targets[targetno]->targetipstr();
}
}
if ((USI->pd = my_pcap_open_live(Targets[0]->deviceName(), 256, (o.spoofsource) ? 1 : 0, pcap_selectable_fd_valid() ? 200 : 2)) == NULL)
fatal("%s", PCAP_OPEN_ERRMSG);
if (USI->ping_scan_arp) {
/* Some OSs including Windows 7 and Solaris 10 have been seen to send their
ARP replies to the broadcast address, not to the (unicast) address that
the request came from, therefore listening for ARP packets directed to
us is not enough. Look inside the ARP reply at the target address field
instead. The filter string will look like
arp and arp[18:4] = 0xAABBCCDD and arp[22:2] = 0xEEFF */
char macstring[2 * ETH_ADDR_LEN + 1];
const u8 *mac = Targets[0]->SrcMACAddress();
assert(mac);
len = Snprintf(macstring, sizeof(macstring), "%02X%02X%02X%02X%02X%02X",
mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
if (len != sizeof(macstring) - 1)
fatal("macstring length is %d, should be %u", len, (unsigned)(sizeof(macstring) - 1));
/* First four bytes of MAC. */
pcap_filter = "arp and arp[18:4] = 0x";
pcap_filter.append(macstring, 0, 4 * 2);
/* Last two bytes. */
pcap_filter += " and arp[22:2] = 0x";
pcap_filter.append(macstring, 4 * 2, 2 * 2);
//its not arp, so lets check if for a protocol scan.
} else if (USI->ping_scan_nd) {
/* Libpcap: IPv6 upper-layer protocol is not supported by proto[x] */
/* Grab the ICMPv6 type using ip6[X:Y] syntax. This works only if there are no
extension headers (top-level nh is IPPROTO_ICMPV6). */
const u8 *srcmac = Targets[0]->SrcMACAddress();
assert(srcmac);
char filterstr[256];
Snprintf(filterstr, 256, "icmp6 and ip6[6:1] = %u and ip6[40:1] = %u",
IPPROTO_ICMPV6, ICMPV6_NEIGHBOR_ADVERTISEMENT);
pcap_filter.append(filterstr);
} else if (USI->prot_scan || (USI->ping_scan && USI->ptech.rawprotoscan)) {
struct sockaddr_storage source;
size_t source_len;
source_len = sizeof(source);
Targets[0]->SourceSockAddr(&source, &source_len);
if (doIndividual) {
pcap_filter = "dst host ";
pcap_filter += inet_ntop_ez(&source, sizeof(source));
pcap_filter += " and (icmp or icmp6 or (";
pcap_filter += dst_hosts;
pcap_filter += "))";
} else {
pcap_filter = "dst host ";