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1 | package Guardian::Events; | |
2 | use strict; | |
3 | use warnings; | |
4 | ||
5 | use Exporter qw(import); | |
6 | ||
7 | our @EXPORT_OK = qw(Init CheckAction GenerateIgnoreList Update); | |
8 | ||
9 | # Hash which stores all supported commands from the queue. | |
10 | my %commands = ( | |
11 | 'count' => \&Counter, | |
12 | 'block' => \&CallBlock, | |
13 | 'unblock' => \&CallUnblock, | |
14 | 'flush' => \&CallFlush, | |
15 | 'reload' => \&main::Reload, | |
16 | 'reload-ignore-list' => \&main::ReloadIgnoreList, | |
17 | 'logrotate' => \&main::Logrotate, | |
18 | ); | |
19 | ||
20 | # Hash to store addresses and their current count. | |
21 | my %counthash = (); | |
22 | ||
23 | # Hash to store all currentyl blocked addresses and a timestamp | |
24 | # when the block for this address can be released. | |
25 | my %blockhash = (); | |
26 | ||
27 | # Hash to store user-defined IP addresses and/or subnets which should be | |
28 | # ignored in case any events should be repored for them. | |
29 | my %ignorehash = (); | |
30 | ||
31 | # Array to store localhost related IP addresses. | |
32 | # They are always white-listed to prevent guardian from blocking | |
33 | # any local traffic. | |
34 | my @localhost_addresses = ("127.0.0.1", "::1"); | |
35 | ||
36 | # This object will contain the reference to the logger object after calling Init. | |
37 | my $logger; | |
38 | ||
39 | # | |
40 | ## The "Init" (Block) function. | |
41 | # | |
42 | ## This function is responsible to initialize Block as a class based object. | |
43 | ## It has to be called once before any blocking event can be processed. | |
44 | # | |
45 | ## The following arguments must be passed, during initialization: | |
46 | ## "BlockCount" and "BlockTime" which both have to be natural numbers. | |
47 | # | |
48 | sub Init (%) { | |
49 | my ( $class, %args ) = @_; | |
50 | my $self = \%args; | |
51 | ||
52 | # Fail, if some critical arguments are missing. | |
53 | unless ((exists($self->{BlockCount})) && (exists($self->{BlockTime}))) { | |
54 | die "Could not initialize Block: Too less arguments are given.\n"; | |
55 | } | |
56 | ||
57 | # Use bless to make "$self" to an object of class "$class". | |
58 | bless($self, $class); | |
59 | ||
60 | # Assign logger object. | |
61 | $logger = $self->{Logger}; | |
62 | ||
63 | # Log used firewall engine. | |
64 | $logger->Log("debug", "Using firewall engine: $self->{FirewallEngine}"); | |
65 | ||
66 | # Try to load the specified firewall engine or die. | |
67 | my $module_name = "Guardian::" . $self->{FirewallEngine}; | |
68 | eval "use $module_name; 1" or die "Could not load a module for firewall engine: $self->{FirewallEngine}!"; | |
69 | ||
70 | # Check if an IgnoreFile has been configured. | |
71 | if (exists($self->{IgnoreFile})) { | |
72 | # Call function to handle the ignore mechanism. | |
73 | &GenerateIgnoreList($self->{IgnoreFile}); | |
74 | } else { | |
75 | # Whitelist local addresses. | |
76 | %ignorehash = &_whitelist_localhost(); | |
77 | } | |
78 | ||
79 | # Return the class object. | |
80 | return $self; | |
81 | } | |
82 | ||
83 | # | |
84 | ## The "Update" Block settings function. | |
85 | # | |
86 | ## This object based function is called to update various class settings. | |
87 | # | |
88 | sub Update (\%) { | |
89 | my $self = shift; | |
90 | ||
91 | # Dereference the given hash-ref and store | |
92 | # the values into a new temporary hash. | |
93 | my %settings = %{ $_[0] }; | |
94 | ||
95 | # Skip settings update if some essential settings are missing. | |
96 | unless ((exists($settings{BlockCount})) && (exists($settings{BlockTime}))) { | |
97 | $logger->Log("err", "Values for BlockCount or BlockTime are missing, keeping previously configured settings."); | |
98 | ||
99 | # Return unmodified class object. | |
100 | return $self; | |
101 | } | |
102 | ||
103 | # Change settings. | |
104 | $self->{BlockCount} = $settings{BlockCount}; | |
105 | $self->{BlockTime} = $settings{BlockTime}; | |
106 | ||
107 | # Return modified class object. | |
108 | return $self; | |
109 | } | |
110 | ||
111 | # | |
112 | ## The main "CheckAction" function. | |
113 | # | |
114 | ## This function is used to handle each recived event from the main event queue of guardian. | |
115 | # | |
116 | ## It will check if the given command is valid and will pass it to the responsible function. | |
117 | # | |
118 | sub CheckAction ($$) { | |
119 | my $self = shift; | |
120 | my @event = split(/ /, $_[0], 4); | |
121 | my ($command, $address, $module, $message) = @event; | |
122 | ||
123 | # Check if we got an invalid command. | |
124 | unless(exists($commands{$command})) { | |
125 | $logger->Log("err", "The CheckAction function has been called with an unsupported command ($command)!"); | |
126 | return; | |
127 | } | |
128 | ||
129 | # Check if the given event contains an address. | |
130 | if ($address) { | |
131 | # Convert and validate the given address. | |
132 | my $bin_address = &Guardian::Base::IPOrNet2Int($address); | |
133 | ||
134 | # Abort if the given address could not be converted because it is not valid. | |
135 | unless ($bin_address) { | |
136 | $logger->Log("err", "Invalid IP address: $address"); | |
137 | return; | |
138 | } | |
139 | ||
140 | # Check if address should be ignored. | |
141 | if(&_IsOnIgnoreList($bin_address)) { | |
142 | # Log message. | |
143 | $logger->Log("info", "Ignoring event for $address, because it is part of the ignore list."); | |
144 | return; | |
145 | } | |
146 | } | |
147 | ||
148 | # Call required handler. | |
149 | my $error = $commands{$command}->($self, $address, $module, $message); | |
150 | ||
151 | # If we got any return code, something went wrong and should be logged. | |
152 | if ($error) { | |
153 | $logger->Log("err", "Got error: $error"); | |
154 | return; | |
155 | } | |
156 | } | |
157 | ||
158 | # | |
159 | ## The main "Counter" function. | |
160 | # | |
161 | ## This function is used to handle each count message + address, which has been sent by the main event | |
162 | ## loop of guardian. | |
163 | # | |
164 | ## It stores the address and the current count into the counthash and increase the count each time when | |
165 | ## the same address should be counted again. When the current count reaches the configured BlockCount, | |
166 | ## the responsible function will be called to block the address. | |
167 | # | |
168 | sub Counter ($@) { | |
169 | my $self = shift; | |
170 | my ($address, $module, $message) = @_; | |
171 | ||
172 | # Log event. | |
173 | $logger->Log("debug", "$module reported $message for address: $address"); | |
174 | ||
175 | # Increase existing count or start counting for new source addresses. | |
176 | if (exists($counthash{$address})) { | |
177 | # Skip already blocked addresses. | |
178 | if (exists($blockhash{$address})) { | |
179 | return undef; | |
180 | } | |
181 | ||
182 | # Increase count of the existing entry. | |
183 | $counthash{$address} = $counthash{$address} + 1; | |
184 | ||
185 | # Log altered count of the address. | |
186 | $logger->Log("debug", "Source $address now has count $counthash{$address}/$self->{BlockCount}..."); | |
187 | } else { | |
188 | # Log that counting for the address has been started. | |
189 | $logger->Log("debug", "Start counting for $address..."); | |
190 | ||
191 | # Set count to "1". | |
192 | $counthash{$address} = 1; | |
193 | } | |
194 | ||
195 | # Check if the address has reached the configured count limit. | |
196 | if ($counthash{$address} >= $self->{BlockCount}) { | |
197 | # Write out log message. | |
198 | $logger->Log("info", "Blocking $address for $self->{BlockTime} seconds..."); | |
199 | ||
200 | # Call block subroutine to block the address. | |
201 | my $error = &CallBlock($self, $address, $module, $message); | |
202 | ||
203 | # Return the message if an error occurs. | |
204 | return $error; | |
205 | } | |
206 | ||
207 | # Everything worked well, return nothing. | |
208 | return undef; | |
209 | } | |
210 | ||
211 | # | |
212 | ## The RemoveBlocks function. | |
213 | # | |
214 | ## This function periodly will be called and is responsible for releasing the block if the Blocktime | |
215 | ## on an address has expired. | |
216 | # | |
217 | ## To do this, the code will loop through all entries of the blockhash and check | |
218 | ## if the estimiated BlockTime of each address has reached and so the block can be released. | |
219 | # | |
220 | sub RemoveBlocks () { | |
221 | my $self = shift; | |
222 | ||
223 | # Get the current time. | |
224 | my $time = time(); | |
225 | ||
226 | # Loop through the blockhash. | |
227 | foreach my $address (keys %blockhash) { | |
228 | # Check if the blocktime for the address has expired. | |
229 | if ($blockhash{$address} <= $time) { | |
230 | # Call unblock subroutine. | |
231 | my $error = &CallUnblock($self, $address, "BlockTime", "has expired for $address"); | |
232 | ||
233 | # Log error messages if returned. | |
234 | if ($error) { | |
235 | $logger->Log("err", "$error"); | |
236 | } | |
237 | } | |
238 | } | |
239 | ||
240 | # Everything okay, return nothing. | |
241 | return undef; | |
242 | } | |
243 | ||
244 | # | |
245 | ## The CallBlock function. | |
246 | # | |
247 | ## This function is called, if the BlockCount for an address is reached or a direct | |
248 | ## request for blocking an address has been recieved. | |
249 | # | |
250 | sub CallBlock ($@) { | |
251 | my $self = shift; | |
252 | my ($address, $module, $message) = @_; | |
253 | ||
254 | # Log the call for blocking an address. | |
255 | $logger->Log("info", "$module - $message"); | |
256 | ||
257 | # Check if an entry for this address exists | |
258 | # in the blockhash. If not, the address has | |
259 | # not been blocked yet, call the responisible | |
260 | # function to do this now. | |
261 | unless (exists($blockhash{$address})) { | |
262 | # Obtain the configured FirewallAction. | |
263 | my $action = $self->{FirewallAction}; | |
264 | ||
265 | # Block the given address. | |
266 | my $error = &DoBlock($address, $action); | |
267 | ||
268 | # If we got back an error message something went wrong. | |
269 | if ($error) { | |
270 | # Exit function and return the used FirewallEngine and the error message. | |
271 | return "$self->{FirewallEngine} - $error"; | |
272 | } else { | |
273 | # Address has been successfully blocked, print a log message. | |
274 | $logger->Log("debug", "Address $address successfully has been blocked..."); | |
275 | } | |
276 | } | |
277 | ||
278 | # Generate time when the block will expire. | |
279 | my $expire = time() + $self->{BlockTime}; | |
280 | ||
281 | # Store the blocked address and the expire time | |
282 | # in the blockhash. | |
283 | $blockhash{$address} = $expire; | |
284 | ||
285 | # Return nothing "undef" if everything is okay. | |
286 | return undef; | |
287 | } | |
288 | ||
289 | # | |
290 | ## CallUnblock function. | |
291 | # | |
292 | ## This function is responsible for unblocking and deleting a given | |
293 | ## address from the blockhash. | |
294 | # | |
295 | sub CallUnblock ($) { | |
296 | my $self = shift; | |
297 | my ($address, $module, $message) = @_; | |
298 | ||
299 | # Log the call for unblocking an address. | |
300 | $logger->Log("info", "$module - $message"); | |
301 | ||
302 | # Return an error if no entry for the given address | |
303 | # is present in the blockhash. | |
304 | unless (exists($blockhash{$address})) { | |
305 | return "Address $address was not blocked!"; | |
306 | } | |
307 | ||
308 | # Unblock the address. | |
309 | my $error = &DoUnblock($address); | |
310 | ||
311 | # If an error message is returned, something went wrong. | |
312 | if ($error) { | |
313 | # Exit function and return the error message. | |
314 | return $error; | |
315 | } else { | |
316 | # Address successfully has been unblocked. | |
317 | $logger->Log("debug", "Address $address successfully has been unblocked..."); | |
318 | } | |
319 | ||
320 | # Drop address from blockhash. | |
321 | delete ($blockhash{$address}); | |
322 | ||
323 | # Drop address from counthash if the address has been unblocked | |
324 | # by the user. This happens when the called module is "Socket". | |
325 | if ($module eq "Socket") { | |
326 | delete ($counthash{$address}); | |
327 | } | |
328 | ||
329 | # Everything worked well, return nothing. | |
330 | return undef; | |
331 | } | |
332 | ||
333 | # | |
334 | ## CallFlush function. | |
335 | # | |
336 | ## This function is responsible for calling the used firewall | |
337 | ## engine to do a flush of the used firewall chain. This will | |
338 | ## clean the entire firewall chain. | |
339 | # | |
340 | sub CallFlush ($) { | |
341 | my $self = shift; | |
342 | ||
343 | # Log the call for flushing. | |
344 | $logger->Log("info", "Flush has been called..."); | |
345 | ||
346 | # Call flush. | |
347 | my $error = &DoFlush(); | |
348 | ||
349 | # If an error message is returned, something went wrong. | |
350 | if ($error) { | |
351 | # Exit function and return the error message. | |
352 | return $error; | |
353 | } else { | |
354 | # Flush successfully has been performed. | |
355 | $logger->Log("debug", "Flush successfully has been performed..."); | |
356 | } | |
357 | ||
358 | # Flush blockhash. | |
359 | %blockhash = (); | |
360 | ||
361 | # Everything worked well, return nothing. | |
362 | return undef; | |
363 | } | |
364 | ||
365 | # | |
366 | ## GenerateIgnoreList function. | |
367 | # | |
368 | ## This function is responsible for generating/updating the | |
369 | ## IgnoreHash which contains all ignored IP addresses and | |
370 | ## networks. | |
371 | # | |
372 | sub GenerateIgnoreList($) { | |
373 | my $file = shift; | |
374 | my @include_files; | |
375 | ||
376 | # Reset current ignore hash and add | |
377 | # localhost related IP addresses. | |
378 | %ignorehash = &_whitelist_localhost(); | |
379 | ||
380 | # Check if the given IgnoreFile could be opened. | |
381 | unless(-e $file) { | |
382 | $logger->Log("err", "The configured IgnoreFile \($file\) could not be opened. Skipped!"); | |
383 | return; | |
384 | } | |
385 | ||
386 | # Open the given IgnoreFile. | |
387 | open (IGNORE, $file); | |
388 | ||
389 | # Read-in the file line by line. | |
390 | while (<IGNORE>) { | |
391 | # Skip comments. | |
392 | next if (/\#/); | |
393 | ||
394 | # Skip blank lines. | |
395 | next if (/^\s*$/); | |
396 | ||
397 | # Remove any newlines. | |
398 | chomp; | |
399 | ||
400 | # Check for an include instruction. | |
401 | if ($_ =~ /^Include_File = (.*)/) { | |
402 | my $include_file = $1; | |
403 | ||
404 | # Check if the parsed include file exists and is read-able. | |
405 | if (-e $include_file) { | |
406 | # Add file to the array of files wich will be included. | |
407 | push(@include_files, $include_file); | |
408 | ||
409 | # Write out log message. | |
410 | $logger->Log("debug", "Addresses from $include_file will be included..."); | |
411 | } else { | |
412 | # Log missing file. | |
413 | $logger->Log("err", "$include_file will not be included. File does not exist!"); | |
414 | } | |
415 | } else { | |
416 | # Check if the line contains a valid single address or network and | |
417 | # convert it into binary format. Store the result/start and | |
418 | # end values in a temporary array. | |
419 | my @values = &Guardian::Base::IPOrNet2Int($_); | |
420 | ||
421 | # If the function returned any values, the line contained a valid | |
422 | # single address or network which successfully has been converted into | |
423 | # binary format. | |
424 | if (@values) { | |
425 | # Assign the array as value to the ignorehash. | |
426 | $ignorehash{$_} = [@values]; | |
427 | } else { | |
428 | # Log invalid entry. | |
429 | $logger->Log("err", "IgnoreFile contains an invalid address/network: $_"); | |
430 | ||
431 | # Skip line. | |
432 | next; | |
433 | } | |
434 | } | |
435 | } | |
436 | ||
437 | # Close filehandle for the IgnoreFile. | |
438 | close (IGNORE); | |
439 | ||
440 | # Check if any files should be included. | |
441 | if (@include_files) { | |
442 | # Loop through the array of files which should be included. | |
443 | foreach my $file (@include_files) { | |
444 | # Open the file. | |
445 | open(INCLUDE, $file); | |
446 | ||
447 | # Read-in file line by line. | |
448 | while(<INCLUDE>) { | |
449 | # Skip any comments. | |
450 | next if (/\#/); | |
451 | ||
452 | # Skip any blank lines. | |
453 | next if (/^\s*$/); | |
454 | ||
455 | # Chomp any newlines. | |
456 | chomp; | |
457 | ||
458 | # Check if the line contains a valid single address or network and | |
459 | # convert it into binary format. Store the result/start and | |
460 | # end values in a temporary array. | |
461 | my @values = &Guardian::Base::IPOrNet2Int($_); | |
462 | ||
463 | # If the function returned any values, the line contained a valid | |
464 | # single address or network which successfully has been converted into | |
465 | # binary format. | |
466 | if (@values) { | |
467 | # Assign the array as value to the ignorehash. | |
468 | $ignorehash{$_} = [@values]; | |
469 | } else { | |
470 | # Log invalid entry. | |
471 | $logger->Log("err", "$file contains an invalid address/network: $_"); | |
472 | ||
473 | # Skip line. | |
474 | next; | |
475 | } | |
476 | } | |
477 | ||
478 | # Close filehandle. | |
479 | close(INCLUDE); | |
480 | } | |
481 | } | |
482 | ||
483 | # Get amount of current elements in hash. | |
484 | my $amount = scalar(keys(%ignorehash)); | |
485 | ||
486 | # Write out log message. | |
487 | $logger->Log("debug", "Ignore list currently contains $amount entries."); | |
488 | } | |
489 | ||
490 | # | |
491 | ## Private function to check if an address is part of the Ignore Hash. | |
492 | # | |
493 | ## This function checks if a passed IP address in binary format (!), | |
494 | ## directly or as part of an ignored network is stored in the ignore hash. | |
495 | # | |
496 | sub _IsOnIgnoreList ($) { | |
497 | my $bin_address = shift; | |
498 | ||
499 | # Loop through the ignore hash and grab the stored values. | |
500 | foreach my $key ( keys %ignorehash ) { | |
501 | # Dereference values array. | |
502 | my @values = @{$ignorehash{$key}}; | |
503 | ||
504 | # Obtain amount of items for the current value array. | |
505 | my $items = scalar @values; | |
506 | ||
507 | # Whether the amount equals one, the given binary address just | |
508 | # needs to be compared against a single address. | |
509 | if ($items eq "1") { | |
510 | my ($ignored_address) = @values; | |
511 | ||
512 | # Simple check if the stored and the given binary address | |
513 | # are the same. | |
514 | if ($bin_address eq $ignored_address) { | |
515 | # The given address is part of the ignore list. | |
516 | $logger->Log("debug", "Address $key found on the ignore list."); | |
517 | ||
518 | # Return "1" (True). | |
519 | return 1; | |
520 | } | |
521 | } | |
522 | ||
523 | # If the amount equals two, for passed binary address needs to | |
524 | # be checked if it is part of the ignored network range. | |
525 | elsif ($items eq "2") { | |
526 | my ($first_address, $last_address) = @values; | |
527 | ||
528 | # Check if the passed binary address is bigger than | |
529 | # the first address and smaler than the last address | |
530 | # (between) the stored network range. | |
531 | if (($bin_address >= $first_address) && ($bin_address <= $last_address)) { | |
532 | # The address is part of an ignored network. | |
533 | $logger->Log("debug", "Address is found inside the ignored network $key."); | |
534 | ||
535 | # Return "1" (True). | |
536 | return 1; | |
537 | } | |
538 | ||
539 | # If the amount is not eighter one or two, the current entry of the ignorehash seems | |
540 | # to be corrupted. Skip and log it. | |
541 | } else { | |
542 | # Write log message about this corruped item in the ignore hash. | |
543 | $logger->Log("err", "Invalid item in the Ignore Hash: $key - @values"); | |
544 | ||
545 | # Skip this element of the ignore hash. | |
546 | next; | |
547 | } | |
548 | } | |
549 | ||
550 | # If we got here, the given address is not part of the ignore hash. | |
551 | # Return nothing (False). | |
552 | return; | |
553 | } | |
554 | ||
555 | # | |
556 | ## The _whitelist_localhost function. | |
557 | # | |
558 | ## This tiny private function simple generates and returns a hash which contains | |
559 | ## the clear and binary converted addresses for all array-stored | |
560 | ## (@localhost_addresses) in an ignorelist compatible format. | |
561 | # | |
562 | sub _whitelist_localhost () { | |
563 | my %temphash; | |
564 | ||
565 | # Loop through the array of localhost related addresses. | |
566 | foreach my $address (@localhost_addresses) { | |
567 | # Validate and convert the addresss into binary format. | |
568 | my @values = &Guardian::Base::IPOrNet2Int($address); | |
569 | ||
570 | # Check if any values are returned. | |
571 | if (@values) { | |
572 | # Store the converted binary values in the temporary hash. | |
573 | $temphash{$address} = [@values]; | |
574 | } | |
575 | } | |
576 | ||
577 | # Return the temporary hash. | |
578 | return %temphash; | |
579 | } | |
580 | ||
581 | 1; |