freebsd-skq

History

cy 8ddae1aa96 calloc() and realloc() modernization. This commit replaces calloc calls, which called calloc() as if it were malloc() by allocating a multiple of objects as a sizeof multiplied by the number of objects. The patch rectifies this by calling calloc() as it was meant to be called. This commit also replaces realloc() with reallocarray() in a similar fashion as above. Instead of calculating the memory to reallocated (changed) by multiplying sizeof by the number of objects, the sizeof and number are passed as separate arguments to reallocarray(), letting reallocarray() do the multiplication instead. Like the calloc() adjustment above, this is approach is cleaner and more elegant than than the previous code. This has been tested on my production firewall and a laptop (also running ipfilter). Submitted by: pfg MFC after: 6 weeks		2017-03-16 04:40:07 +00:00
..
Celler
ipsd.c	calloc() and realloc() modernization.	2017-03-16 04:40:07 +00:00
ipsd.h
ipsdr.c	calloc() and realloc() modernization.	2017-03-16 04:40:07 +00:00
linux.h
Makefile
README
sbpf.c
sdlpi.c
slinux.c
snit.c

README

IP Scan Detetor.
----------------

This program is designed to be a passive listener for TCP packets sent to
the host.  It does not exercise the promiscous mode of interfaces.  For
routing Unix boxes (and firewalls which route/proxy) this is sufficient to
detect all packets going to/through them.

Upon compiling, a predefined set of "sensitive" ports are configured into
the program.  Any TCP packets which are seen sent to these ports are counted
and the IP# of the sending host recorded, along with the time of the first
packet to that port for that IP#.

After a given number of "hits", it will write the current table of packets
out to disk.  This number defaults to 10,000.

To analyze the information written to disk, a sample program called "ipsdr"
is used (should but doesn't implement a tree algorithm for storing data)
which  reads all log files it recognises and totals up the number of ports
each host hit.  By default, all ports have the same weighting (1).  Another
group of passes is then made over this table using a netmask of 0xfffffffe,
grouping all results which fall under the same resulting IP#.  This netmask
is then shrunk back to 0, with a output for each level given.  This is aimed
at detecting port scans done from different hosts on the same subnet (although
I've not seen this done, if one was trying to do it obscurely...)

Lastly, being passive means that no action is taken to stop port scans being
done or discourage them.

Darren
darrenr@pobox.com