248 lines
9.9 KiB
Django/Jinja
Executable File
248 lines
9.9 KiB
Django/Jinja
Executable File
#!/usr/bin/perl -w
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# {{ ansible_managed }}
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# dhcp_probe_notify2 -p calling_prog_name -I interface_name -i IPaddress -m MACaddress [-y yiaddr]
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#
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# An external program called by dhcp_probe upon response of a response from an unexpected BootP/DHCP server.
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#
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# Called via specification of 'alert_program_name2' in /etc/dhcp_probe.cf file.
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# This version obeys the syntax provided by the 'alert_program_name2' statement,
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# not the syntax provided by the older 'alert_program_name' statement.
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#
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# Required options:
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# -p calling_prog_name the name of the calling program (e.g. 'dhcp_probe')
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# -I interface_name the name of the interface on which the unexpected response packet arrived (e.g. 'qfe0')
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# -i IPaddress the IP source address of the unexpected response packet (e.g. '192.168.0.1')
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# -m MACaddress the Ethernet source address of the unexpected response packet (e.g. '0:1:2:3:4:5')
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#
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# Optional options:
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# -y yiaddr the response packet's non-zero yiaddr value, when it falls within a "Lease Network of Interest" (e.g. '172.16.1.2')
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#
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# May send email subject to throttling.
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# May send page subject to throttling.
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#
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# You will need to edit the definitions below.
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#
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# Irwin Tillman
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use Sys::Hostname;
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use Sys::Syslog qw(:DEFAULT setlogsock);
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use Time::HiRes qw(gettimeofday); # from CPAN
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use Getopt::Std;
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use strict;
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#############################################################################
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#
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# Definitions you may need to edit
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my $SYSLOG_FACILITY="daemon"; # name of facility to use if syslogging (e.g. 'daemon')
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my $SYSLOG_OPT = 'pid,cons'; # comma-separated syslog options to use if syslogging (e.g. 'pid,cons') , ignored if not syslogging
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use vars qw($VERBOSE);
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$VERBOSE = 1; # set to true to produce more verbose messages
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# We may send one piece of mail this way, subject to frequency throttling.
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# Use this set of definitions for a piece of email that is delivered as regular email (not a page).
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use vars qw($THROTTLE_MAIL_CMD $THROTTLE_MAIL_TIMEOUT $THROTTLE_MAIL_FROM $THROTTLE_MAIL_RECIPIENT $THROTTLE_MAIL_RECIPIENT_TEST $THROTTLE_MAIL_SUBJECT);
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{% if dhcpd_probe_mail_to|d() and dhcpd_probe_mail_to %}
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$THROTTLE_MAIL_CMD = "{{ ansible_local.root.lib + '/dhcp-probe/mail-throttled' }}"; # set to "" to disable
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{% else %}
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$THROTTLE_MAIL_CMD = ""; # set to "" to disable
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{% endif %}
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$THROTTLE_MAIL_TIMEOUT = {{ dhcpd_probe_mail_timeout | default('600') }}; # seconds
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$THROTTLE_MAIL_FROM = "root"; # e.g. "root"
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$THROTTLE_MAIL_RECIPIENT = "{{ dhcpd_probe_mail_to | join(' ') | replace('@','\@') }}"; # space-separated email addresses, remember to escape '@' characters
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$THROTTLE_MAIL_SUBJECT = "Unexpected BOOTP/DHCP server";
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# We may also send another piece of email this way, subject to frequency throttling.
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# Use this set of definitions for a piece of email that is delivered to a pager (not as regular email).
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use vars qw($THROTTLE_PAGE_CMD $THROTTLE_PAGE_TIMEOUT $THROTTLE_PAGE_RECIPIENT);
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{% if dhcpd_probe_page_to|d() and dhcpd_probe_page_to %}
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$THROTTLE_PAGE_CMD = "{{ ansible_local.root.lib + '/dhcp-probe/mail-throttled' }}"; # set to "" to disable
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{% else %}
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$THROTTLE_PAGE_CMD = ""; # set to "" to disable
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{% endif %}
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$THROTTLE_PAGE_TIMEOUT = {{ dhcpd_probe_page_timeout | default('600') }}; # seconds
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$THROTTLE_PAGE_RECIPIENT = "{{ dhcpd_probe_page_to | join(' ') | replace('@','\@') }}"; # space-separated email addresses, remember to escape '@' characters
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# End of definitions you may need to edit
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#
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#############################################################################
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(my $prog = $0) =~ s/.*\///;
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# init our use of syslog
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# setlogsock('unix'); # talk to syslog with UNIX domain socket, not INET domain. XXX causes failure in Solaris 7
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openlog($prog, $SYSLOG_OPT, $SYSLOG_FACILITY);
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#############################################################################
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#
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# Parse options and arguments
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# We must use getopt() instead of getopts() to avoid throwing an error
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# if we are passed an unrecognized option.
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# We must silently ignore unrecognized options to be forward compatible with enhancements to dhcp_probe.
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use vars qw($opt_i $opt_I $opt_m $opt_p $opt_y);
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# &getopt('p:i:I:m:y:');
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&getopt('piImy');
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# Required options
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my $calling_program = $opt_p;
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my $ifname = $opt_I;
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my $ip_src = $opt_i;
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my $ether_src = $opt_m;
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#
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# Optional options
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my $yiaddr = $opt_y || "";
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# Enforce presence of required options
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unless ($calling_program) {
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my_message('LOG_ERR', "${prog}: missing -p calling_program option");
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exit 100;
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}
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unless ($ifname) {
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my_message('LOG_ERR', "${prog}: missing -I interface_name option");
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exit 101;
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}
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unless ($ip_src) {
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my_message('LOG_ERR', "${prog}: missing -i ip_src_address option");
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exit 102;
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}
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unless ($ether_src) {
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my_message('LOG_ERR', "${prog}: missing -m ether_src_address option");
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exit 103;
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}
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# Done parsing options and arguments
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#
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#############################################################################
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# Miscellaneous Initialization
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my $hostname = hostname();
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my ($seconds, $microseconds) = gettimeofday; # from Time::HiRes on CPAN
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my $timestamp = scalar(localtime($seconds));
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$timestamp =~ s/(\d\d:\d\d:\d\d)/$1.$microseconds/; # glue microsends to end of seconds
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# When we pass a key to THROTTLE_MAIL_CMD, we want the key to also include an indication
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# of whether the yiaddr option was specified. (If we didn't include such an indication,
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# the following could happen: The first response we detect from a rogue server doesn't
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# distribute an "address of concern", so the yiaddr option wasn't specified. We alert
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# based on that. The next response we detect from a rogue server does distribute an
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# "address of concern", so the yiaddr is specified. Our alert gets throttled since
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# the first alert we sent was "recent". But this means the administrator doesn't get
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# notified that the rogue distributed an "address of interest". So we need to
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# include the state of yiaddr option in the key we pass to THROTTLE_MAIL_CMD,
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# to ensure the second response isn't throttled using the same key as the first response.)
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#
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# We can't just use the value of yiaddr itself as the string to incorporate into the key,
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# as that would result in a unqiue key for each distributed IP address. Instead, we
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# will use the state of yiaddr (set or unset).
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#
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# Note this means that when a rogue DHCP server is distributing IP addresses that fall into "Networks of Concern",
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# we will very likely send more than one notification for it within each throttle period.
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# That's because while some of the responses from the rogue will have a yiaddr within a "Networks of Concern",
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# others (for example, DHCPNAK responses) will not. This is unfortunate, but is better than the
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# alternative approach (of not taking into account the yiaddr state in the key), since that will
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# sometimes cause you to not be alerted at all to the "yiaddr falls into a Network of Concern" situation.
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#
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# Create a string based on the state of yiaddr, for later incorporation into the key.
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my $yiaddr_option_state = $yiaddr ? "yiaddr=set" : "yiaddr=unset";
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#############################################################################
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if ($THROTTLE_MAIL_CMD) {
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# This command suppresses the message if it's sent a message to 'key' within 'throttle_seconds'
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# I use the calling program's name and the offender's hardware address as the key.
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my $subject_yiaddr_addendum = "";
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$subject_yiaddr_addendum = ", YIADDR=$yiaddr" if $yiaddr;
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unless (open(THROTTLE_MAIL, "| $THROTTLE_MAIL_CMD -l -k ${calling_program}_mail_${ether_src}_$yiaddr_option_state -t $THROTTLE_MAIL_TIMEOUT -f \"$THROTTLE_MAIL_FROM\" -r \"$THROTTLE_MAIL_RECIPIENT\" -s\"$THROTTLE_MAIL_SUBJECT (MAC=${ether_src}, IP=${ip_src}${subject_yiaddr_addendum})\"")) {
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my_message('LOG_ERR', "${prog}: failure trying to send throttled email: can't execute '${THROTTLE_MAIL_CMD}': open(): $!");
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exit 20;
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}
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print THROTTLE_MAIL
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$timestamp, "\n",
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"\n",
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"$calling_program detected an unexpected BOOTP/DHCP server.\n",
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"Host=$hostname, interface=${ifname}, IP source=${ip_src}, Ethernet source=${ether_src}\n";
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print THROTTLE_MAIL "\nThis means that *there is* a rogue BOOTP/DHCP server operating.\n" if $VERBOSE;
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if ($yiaddr) {
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print THROTTLE_MAIL
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"The server distributed IP address $yiaddr, which falls into a network of special concern.\n";
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}
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unless (close(THROTTLE_MAIL)) {
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my_message('LOG_ERR',
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"${prog}: failure trying to send throttled email: error executing '${THROTTLE_MAIL_CMD}': close(): " .
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($! ?
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"syserr closing pipe: $!"
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:
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"wait status $? from pipe"
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) .
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"\n"
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);
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exit 21;
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}
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}
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if ($THROTTLE_PAGE_CMD) {
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# This command suppresses the message if it's sent a message to 'key' within 'throttle_seconds'
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# I use the calling program's name and the offender's hardware address as the key.
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unless (open(THROTTLE_PAGE, "| $THROTTLE_PAGE_CMD -l -k ${calling_program}_page_${ether_src}_$yiaddr_option_state -t $THROTTLE_PAGE_TIMEOUT -r \"$THROTTLE_PAGE_RECIPIENT\"")) {
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my_message('LOG_ERR', "${prog}: failure trying to send throttled page: can't execute '${THROTTLE_PAGE_CMD}': open(): $!\n");
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exit 30;
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}
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print THROTTLE_PAGE "Rogue DHCP server IP=$ip_src MAC=$ether_src seen via host $hostname interface $ifname\n";
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print THROTTLE_PAGE "This means *there is* a rogue BOOTP/DHCP server operating.\n" if $VERBOSE;
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if ($yiaddr) {
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print THROTTLE_PAGE
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"Rogue server distributed yiaddr=$yiaddr, a special concern.\n";
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}
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unless (close(THROTTLE_PAGE)) {
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my_message('LOG_ERR',
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"${prog}: failure trying to send throttled page: error executing '${THROTTLE_PAGE_CMD}': close(): " .
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($! ?
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"syserr closing pipe: $!"
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:
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"wait status $? from pipe"
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) .
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"\n"
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);
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exit 31;
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}
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}
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exit 0;
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#############################################################################
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sub my_message {
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# Call with a syslog priority constant and a message string.
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# We write the message to syslog, using the specified priority.
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# Your message should not contain a newline.
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my($priority, $msg) = @_;
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syslog($priority, $msg);
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return;
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}
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