including alias extension, in several places to avoid this error message
when an alias has an IP address but the primary interface doesn't:
Failed to lookup subnet/netmask for device (venet0): venet0: no IPv4 address assigned
The patch also considers an interface alias if the primary interface
does not appear in the list of interfaces (perhaps because it does not
have an IP address assigned) when building the table of routes.
target address address field, not the destination address in the
enclosing ethernet frame. Some operating systems, including Windows
7 and Solaris 10, are known to at least sometimes send their ARP
replies to the broadcast address and Nmap wouldn't notice them. The
symptom of this was that root scans wouldn't work ("Host seems
down") but non-root scans would work. Thanks to Mike Calmus and
Vijay Sankar for reporting the problem, and Marcus Haebler for
suggesting the fix.
o Fixed a log_write call and a pfatal call to use a syntax which is
safer from format strings bugs. This allows Nmap to build with the
gcc -Wformat -Werror=format-security options. [Guillaume Rousse]
code to increase the scan delay if tries increased too much. But the
main loop did an unconditional continue before incrementing tries, so it
was always 0. I looked back at the history and saw that it was always
like this for RPC scan. tries was only incremented for the other scan
types handled by pos_scan, which now are done by ultra_scan. So I
removed the tries accounting and dependent code.
a layer 4 protocol used mostly for telephony related applications.
This brings the following new features:
o SCTP INIT chunk port scan (-sY): open ports return an INIT-ACK
chunk, closed ones an ABORT chunk. This is the SCTP equivalent
of a TCP SYN stealth scan.
o SCTP COOKIE-ECHO chunk port scan (-sZ): open ports are silent,
closed ports return an ABORT chunk.
o SCTP INIT chunk ping probes (-PY): host discovery using SCTP
INIT chunk packets.
o SCTP-specific IP protocol scan (-sO -p sctp).
o SCTP-specific traceroute support (--traceroute).
o The ability to use the deprecated Adler32 algorithm as specified
in RFC 2960 instead of CRC32C from RFC 4960 (--adler32).
o 42 well-known SCTP ports were added to the nmap-services file.
Part of the work on SCTP support was kindly sponsored by
Compass Security AG, Switzerland. [Daniel Roethlisberger]
right type of probe (0 with 8, 14 with 13, 18 with 17). With the new
default ping, I was scanning a network where an echo reply would
mistakenly be interpreted as a response to a timestamp request, even
though that host didn't respond to timestamp requests. That host would
become the global ping host, and all its probes would be dropped,
slowing the scan way down. A ping scan of a /24 took over 1,000 seconds
when it should have taken about 10.
exhaustive testing of 90 different probes, this one emerged as the
best four-probe combination, finding 14% more Internet hosts than
the previous default, -PE -PA80. The default for nonroot users is
-PS80,443, replacing the previous default of -PS80. In addition,
ping probes are now sent in order of effectiveness (-PE first) so
that less likely probes may not have to be sent.
Found whacked packet protocol 17 in get_ping_pcap_result
and rewrite it
Received packet with protocol 17; ignoring.
The message is printed when we receive a packet we can't use during a
ping scan, but it's not "whacked" to receive a UDP packet during a TCP
scan for example.
that it is set properly for ping scan. Previously status reports during
ping scan always looked like
Stats: 25:34:33 elapsed; 991232 hosts completed (72530 up), 0 undergoing Ping Scan
Note the "0 undergoing". Now that number will be set to 4096 or whatever
the current ping scan group size happens to be.
increases the scan dealy with an increase in max_successful_tryno. When I
reverted a bunch of changes in r11651, I removed the moved code, leaving the
scan delay increase nowhere. This puts it back in ultrascan_port_probe_update
where it was before.
Don't make a host the global ping host until it moves to the completed
hosts list, and only change the global ping probe if the new probe is no
worse than the old (according to pingprobe_is_better).
Restore the ping magnifier for host congestion window updates.
Ignore the timing of certain ICMP errors that are likely to be rate
limited and don't change the port or host state. Avoid making timing
pings out of probes that elicit such errors. This used to be done only
for port scans and only at -T4 and above (and didn't prohibit the
creation of timing pings). Now it is done for host discovery too, and at
all timing levels.
Gracefully handle updates from the recent past in RateMeter. Doesn't
affect performance, but avoids a rare assertion failure.
num_probes_active == 0 in HostScanStats::completed. The reason for this is
fairly subtle and I didn't realize it at first: We have to make sure there are
no active probes because once in the completed list, probes don't time out.
Probes that are active stay active in the count. If the congestion window ever
falls below the number of these active probes, the program will hang waiting
for them to time out.
We could get away with this in the case of up hosts, because we call
HostScanStats::destroyAllOutstandingProbes in that case. We could do that in
the down case too, but that would prohibit a down host from being found up
later on. That's currently a matter of some luck; we don't keep sending probes
after a host is down but will accept replies to any other probes that have
already been sent.
source address didn't match the target address. Fyodor correctly pointed out
that this is wrong for UDP scans, when we need to slow down for a firewall
sending unreachables to know which probes don't elicit one. I'm going to try
something a little different in nmap-perf.
is up or down, we can move it to the completed list, regardless of any active
probes. However I can imagine changing this so that we move it when it is found
up, or when it is found down and there are no probes left to send. That would
give a down host a chance to become up with a different probe later on.
checking if a pingprobe has been set. We always use PORT_UNKNOWN during host
discovery (rather than HOST_UP or HOST_DOWN) to avoid conflicts with other
PORT_* constants. See the log for r8784.
num_probes_outstanding() == 0. The active probes are probes that haven't timed
out; the outstanding probes includes those and some timed-out probes. When a
host makes it to the completed list with outstanding probes, it is unlikely
they will ever be removed, so we weren't sending any global pings in some
cases. A host only moves to the completed list with it has no active probes,
and any active probes it has after that are global pings.
Also remove only timed-out ping probes from the ping host. All other probes are
timed out but waiting for a response.
me) in r8784 when I made the change to retain ping probes between ping scanning
and port scanning.
It only gets set during host discovery scans, because that's how it was before,
but it might be advantageous to set it during port scans as well.
target. In my testing, TCP scanning certain hosts, other hosts send back ICMP
destination unreachables (admin prohibited) for some ports (the Microsoft
ports). If that's the only response we got from a host, we would make it the
timing ping probe. But the admin-prohibiteds come back at some very slow rate,
much slower than the 1.25/s ping interval. So most of them are dropped, keeping
the congestion window perpetually at 1 and slowly increasing the scan delay. In
a -F scan these hosts could take over twice as long as any other host.
I also put in some missing adjust_timing arguments to the host and ping update
functions whenever adjust_timing could be false (the default is true). I think
those were just oversights. I also made it so that we don't select a new ping
probe when adjust_timing is false; there's no point sending ping probes whose
responses we're going to ignore.
positive response that results in being marked filtered, the reply was an ICMP
error. Such probes are now ranked a 2 along with UDP, IP proto, and other
probes that get ICMP replies that are likely to be rate limited. Previously
they got the highest rank, 6, because they were TCP probes other than SYN to an
open port. SYN to an open port retains its rank of 3.
socket). It's possible to get an EHOSTUNREACH or EHOSTDOWN (and possibly other
errors) against a nonexistent LAN host and formerly the socket wasn't closed.
This allowed Nmap's internal count of sockets to be less that the true count of
open sockets. It would eventually try to open too many sockets and quit with
the message
Socket creation in sendConnectScanProbe: Too many open files (24)
Be aware that in this message 24 is the errno, not the number of open files.
i.e., the probe didn't just time out. This was the case before r11253 when I
mistakenly removed it. I meant only to allow ultrascan_adjust_timing to be
called when rcvdtime == NULL, but as a side effect I also allowed
max_successful_tryno to increase in that case too. I was able to get that bit
of code to run with rcvdtime == NULL in a normal scan, but I don't think it
happens often.
I also improved the comments in that block of code.
GroupScanStats::probeSent. This will allow updating timing variables for a
per-host rate limiter.
This fixes a bug, which was that decoy probes were not recorded by the scan
rate meter. Decoy scans would show a lower scan rate than the actual: with four
decoys the rate printed would be 1/5 of actual. This only affects printed
output, not the actual scan rate.
replied to or times out. Previously the scaling factor was increased as soon a
s a probe was sent. So if you sent 10 probes right away at the beginning of the
scan, the first reply that came back would be scaled by 10 (= 10/1, and the
next by 9/2, etc.). Now if every probe is replied to then the scaling factor
will be exactly 1 throughout the scan.
completed hosts from the lists after two minutes. These hosts are
kept around in case there is a late response, but this draws the
line on how long we wait and hence keep this information in memory.
See http://seclists.org/nmap-dev/2008/q3/0902.html for more.
