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df6ec59f SS |
1 | package Guardian::Events; |
2 | use strict; | |
3 | use warnings; | |
4 | ||
5 | use Exporter qw(import); | |
6 | ||
7c8f0696 | 7 | our @EXPORT_OK = qw(Init CheckAction GenerateIgnoreList Update); |
df6ec59f SS |
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 | ); | |
16 | ||
17 | # Hash to store addresses and their current count. | |
18 | my %counthash = (); | |
19 | ||
20 | # Hash to store all currentyl blocked addresses and a timestamp | |
21 | # when the block for this address can be released. | |
22 | my %blockhash = (); | |
23 | ||
66e1ad0a SS |
24 | # Hash to store user-defined IP addresses and/or subnets which should be |
25 | # ignored in case any events should be repored for them. | |
26 | my %ignorehash = (); | |
27 | ||
df6ec59f SS |
28 | # This object will contain the reference to the logger object after calling Init. |
29 | my $logger; | |
30 | ||
31 | # | |
32 | ## The "Init" (Block) function. | |
33 | # | |
34 | ## This function is responsible to initialize Block as a class based object. | |
35 | ## It has to be called once before any blocking event can be processed. | |
36 | # | |
37 | ## The following arguments must be passed, during initialization: | |
38 | ## "BlockCount" and "BlockTime" which both have to be natural numbers. | |
39 | # | |
40 | sub Init (%) { | |
41 | my ( $class, %args ) = @_; | |
42 | my $self = \%args; | |
43 | ||
44 | # Fail, if some critical arguments are missing. | |
45 | unless ((exists($self->{BlockCount})) && (exists($self->{BlockTime}))) { | |
46 | die "Could not initialize Block: Too less arguments are given.\n"; | |
47 | } | |
48 | ||
49 | # Use bless to make "$self" to an object of class "$class". | |
50 | bless($self, $class); | |
51 | ||
52 | # Assign logger object. | |
53 | $logger = $self->{Logger}; | |
54 | ||
55 | # Log used firewall engine. | |
56 | $logger->Log("debug", "Using firewall engine: $self->{FirewallEngine}"); | |
57 | ||
58 | # Try to load the specified firewall engine or die. | |
59 | my $module_name = "Guardian::" . $self->{FirewallEngine}; | |
60 | eval "use $module_name; 1" or die "Could not load a module for firewall engine: $self->{FirewallEngine}!"; | |
61 | ||
66e1ad0a SS |
62 | # Check if an IgnoreFile has been configured. |
63 | if (exists($self->{IgnoreFile})) { | |
64 | # Call function to handle the ignore mechanism. | |
65 | &GenerateIgnoreList($self->{IgnoreFile}); | |
66 | } | |
67 | ||
df6ec59f SS |
68 | # Return the class object. |
69 | return $self; | |
70 | } | |
71 | ||
72 | # | |
73 | ## The main "CheckAction" function. | |
74 | # | |
75 | ## This function is used to handle each recived event from the main event queue of guardian. | |
76 | # | |
77 | ## It will check if the given command is valid and will pass it to the responsible function. | |
78 | # | |
79 | sub CheckAction ($$) { | |
80 | my $self = shift; | |
81 | my @event = split(/ /, $_[0], 4); | |
82 | my ($command, $address, $module, $message) = @event; | |
83 | ||
84 | # Check if we got an invalid command. | |
85 | unless(exists($commands{$command})) { | |
86 | $logger->Log("err", "The CheckAction function has been called with an unsupported command ($command)!"); | |
87 | return; | |
88 | } | |
89 | ||
66e1ad0a SS |
90 | # Convert and validate the given address. |
91 | my $bin_address = &Guardian::Base::IPOrNet2Int($address); | |
92 | ||
93 | # Abort if the given address could not be converted because it is not valid. | |
94 | unless ($bin_address) { | |
bc97b7c0 SS |
95 | $logger->Log("err", "Invalid IP address: $address"); |
96 | return; | |
97 | } | |
df6ec59f | 98 | |
66e1ad0a SS |
99 | # Check if address should be ignored. |
100 | if(&_IsOnIgnoreList($bin_address)) { | |
101 | # Log message. | |
102 | $logger->Log("info", "Ignoring event for $address, because it is part of the ignore list."); | |
103 | return; | |
104 | } | |
105 | ||
df6ec59f SS |
106 | # Call required handler. |
107 | my $error = $commands{$command}->($self, $address, $module, $message); | |
108 | ||
109 | # If we got any return code, something went wrong and should be logged. | |
110 | if ($error) { | |
111 | $logger->Log("err", "Got error: $error"); | |
112 | return; | |
113 | } | |
114 | } | |
115 | ||
116 | # | |
117 | ## The main "Counter" function. | |
118 | # | |
119 | ## This function is used to handle each count message + address, which has been sent by the main event | |
120 | ## loop of guardian. | |
121 | # | |
122 | ## It stores the address and the current count into the counthash and increase the count each time when | |
123 | ## the same address should be counted again. When the current count reaches the configured BlockCount, | |
124 | ## the responsible function will be called to block the address. | |
125 | # | |
126 | sub Counter ($@) { | |
127 | my $self = shift; | |
128 | my ($address, $module, $message) = @_; | |
129 | ||
130 | # Log event. | |
131 | $logger->Log("debug", "$module reported $message for address: $address"); | |
132 | ||
133 | # Increase existing count or start counting for new source addresses. | |
134 | if (exists($counthash{$address})) { | |
135 | # Skip already blocked addresses. | |
136 | if (exists($blockhash{$address})) { | |
137 | return undef; | |
138 | } | |
139 | ||
140 | # Increase count of the existing entry. | |
141 | $counthash{$address} = $counthash{$address} + 1; | |
142 | ||
143 | # Log altered count of the address. | |
144 | $logger->Log("debug", "Source $address now has count $counthash{$address}/$self->{BlockCount}..."); | |
145 | } else { | |
146 | # Log that counting for the address has been started. | |
147 | $logger->Log("debug", "Start counting for $address..."); | |
148 | ||
149 | # Set count to "1". | |
150 | $counthash{$address} = 1; | |
151 | } | |
152 | ||
153 | # Check if the address has reached the configured count limit. | |
154 | if ($counthash{$address} >= $self->{BlockCount}) { | |
155 | # Write out log message. | |
156 | $logger->Log("info", "Blocking $address for $self->{BlockTime} seconds..."); | |
157 | ||
158 | # Call block subroutine to block the address. | |
159 | my $error = &CallBlock($self, $address, $module, $message); | |
160 | ||
161 | # Return the message if an error occurs. | |
162 | return $error; | |
163 | } | |
164 | ||
165 | # Everything worked well, return nothing. | |
166 | return undef; | |
167 | } | |
168 | ||
169 | # | |
170 | ## The RemoveBlocks function. | |
171 | # | |
172 | ## This function periodly will be called and is responsible for releasing the block if the Blocktime | |
173 | ## on an address has expired. | |
174 | # | |
175 | ## To do this, the code will loop through all entries of the blockhash and check | |
176 | ## if the estimiated BlockTime of each address has reached and so the block can be released. | |
177 | # | |
178 | sub RemoveBlocks () { | |
179 | my $self = shift; | |
180 | ||
181 | # Get the current time. | |
182 | my $time = time(); | |
183 | ||
184 | # Loop through the blockhash. | |
185 | foreach my $address (keys %blockhash) { | |
186 | # Check if the blocktime for the address has expired. | |
187 | if ($blockhash{$address} <= $time) { | |
188 | # Call unblock subroutine. | |
189 | my $error = &CallUnblock($self, $address, "BlockTime", "has expired for $address"); | |
190 | ||
191 | # Log error messages if returned. | |
192 | if ($error) { | |
193 | $logger->Log("err", "$error"); | |
194 | } | |
195 | } | |
196 | } | |
197 | ||
198 | # Everything okay, return nothing. | |
199 | return undef; | |
200 | } | |
201 | ||
202 | # | |
203 | ## The CallBlock function. | |
204 | # | |
205 | ## This function is called, if the BlockCount for an address is reached or a direct | |
206 | ## request for blocking an address has been recieved. | |
207 | # | |
208 | sub CallBlock ($@) { | |
209 | my $self = shift; | |
210 | my ($address, $module, $message) = @_; | |
211 | ||
212 | # Log the call for blocking an address. | |
213 | $logger->Log("info", "$module - $message"); | |
214 | ||
215 | # Check if an entry for this address exists | |
216 | # in the blockhash. If not, the address has | |
217 | # not been blocked yet, call the responisible | |
218 | # function to do this now. | |
219 | unless (exists($blockhash{$address})) { | |
e9c558fe SS |
220 | # Obtain the configured FirewallAction. |
221 | my $action = $self->{FirewallAction}; | |
df6ec59f SS |
222 | |
223 | # Block the given address. | |
224 | my $error = &DoBlock($address, $action); | |
225 | ||
226 | # If we got back an error message something went wrong. | |
227 | if ($error) { | |
f842727a SS |
228 | # Exit function and return the used FirewallEngine and the error message. |
229 | return "$self->{FirewallEngine} - $error"; | |
df6ec59f SS |
230 | } else { |
231 | # Address has been successfully blocked, print a log message. | |
232 | $logger->Log("debug", "Address $address successfully has been blocked..."); | |
233 | } | |
234 | } | |
235 | ||
236 | # Generate time when the block will expire. | |
237 | my $expire = time() + $self->{BlockTime}; | |
238 | ||
239 | # Store the blocked address and the expire time | |
240 | # in the blockhash. | |
241 | $blockhash{$address} = $expire; | |
242 | ||
243 | # Return nothing "undef" if everything is okay. | |
244 | return undef; | |
245 | } | |
246 | ||
247 | # | |
248 | ## CallUnblock function. | |
249 | # | |
250 | ## This function is responsible for unblocking and deleting a given | |
251 | ## address from the blockhash. | |
252 | # | |
253 | sub CallUnblock ($) { | |
254 | my $self = shift; | |
255 | my ($address, $module, $message) = @_; | |
256 | ||
257 | # Log the call for unblocking an address. | |
258 | $logger->Log("info", "$module - $message"); | |
259 | ||
260 | # Return an error if no entry for the given address | |
261 | # is present in the blockhash. | |
262 | unless (exists($blockhash{$address})) { | |
263 | return "Address $address was not blocked!"; | |
264 | } | |
265 | ||
266 | # Unblock the address. | |
267 | my $error = &DoUnblock($address); | |
268 | ||
269 | # If an error message is returned, something went wrong. | |
270 | if ($error) { | |
271 | # Exit function and return the error message. | |
272 | return $error; | |
273 | } else { | |
274 | # Address successfully has been unblocked. | |
275 | $logger->Log("debug", "Address $address successfully has been unblocked..."); | |
276 | } | |
277 | ||
278 | # Drop address from blockhash. | |
279 | delete ($blockhash{$address}); | |
280 | ||
281 | # Everything worked well, return nothing. | |
282 | return undef; | |
283 | } | |
284 | ||
66e1ad0a SS |
285 | # |
286 | ## GenerateIgnoreList function. | |
287 | # | |
288 | ## This function is responsible for generating/updating the | |
289 | ## IgnoreHash which contains all ignored IP addresses and | |
290 | ## networks. | |
291 | # | |
292 | sub GenerateIgnoreList($) { | |
293 | my $file = shift; | |
294 | ||
295 | # Check if the given IgnoreFile could be opened. | |
296 | unless(-e $file) { | |
297 | $logger->Log("err", "The configured IgnoreFile \($file\) could not be opened. Skipped!"); | |
298 | return; | |
299 | } | |
300 | ||
301 | # Open the given IgnoreFile. | |
302 | open (IGNORE, $file); | |
303 | ||
304 | # Read-in the file line by line. | |
305 | while (<IGNORE>) { | |
306 | # Skip comments. | |
307 | next if (/\#/); | |
308 | ||
309 | # Skip blank lines. | |
310 | next if (/^\s*$/); | |
311 | ||
312 | # Remove any newlines. | |
313 | chomp; | |
314 | ||
315 | # Check if the line contains a valid single address or network and | |
316 | # convert it into binary format. Store the result/start and | |
317 | # end values in a temporary array. | |
318 | my @values = &Guardian::Base::IPOrNet2Int($_); | |
319 | ||
320 | # If the function returned any values, the line contained a valid | |
321 | # single address or network which successfully has been converted into | |
322 | # binary format. | |
323 | if (@values) { | |
324 | # Assign the array as value to the ignorehash. | |
325 | $ignorehash{$_} = [@values]; | |
326 | } else { | |
327 | # Log invalid entry. | |
328 | $logger->Log("err", "IgnoreFile contains an invalid address/network: $_"); | |
329 | ||
330 | # Skip line. | |
331 | next; | |
332 | } | |
333 | } | |
334 | ||
335 | # Close filehandle for the IgnoreFile. | |
336 | close (IGNORE); | |
337 | } | |
338 | ||
339 | # | |
340 | ## Private function to check if an address is part of the Ignore Hash. | |
341 | # | |
7c8f0696 SS |
342 | ## This function checks if a passed IP address in binary format (!), |
343 | ## directly or as part of an ignored network is stored in the ignore hash. | |
66e1ad0a SS |
344 | # |
345 | sub _IsOnIgnoreList ($) { | |
346 | my $bin_address = shift; | |
347 | ||
348 | # Loop through the ignore hash and grab the stored values. | |
349 | foreach my $key ( keys %ignorehash ) { | |
350 | # Dereference values array. | |
351 | my @values = @{$ignorehash{$key}}; | |
352 | ||
353 | # Obtain amount of items for the current value array. | |
354 | my $items = scalar @values; | |
355 | ||
356 | # Whether the amount equals one, the given binary address just | |
357 | # needs to be compared against a single address. | |
358 | if ($items eq "1") { | |
359 | my ($ignored_address) = @values; | |
360 | ||
361 | # Simple check if the stored and the given binary address | |
362 | # are the same. | |
363 | if ($bin_address eq $ignored_address) { | |
364 | # The given address is part of the ignore list. | |
365 | $logger->Log("debug", "Address $key found on the ignore list."); | |
366 | ||
367 | # Return "1" (True). | |
368 | return 1; | |
369 | } | |
370 | } | |
371 | ||
372 | # If the amount equals two, for passed binary address needs to | |
373 | # be checked if it is part of the ignored network range. | |
374 | elsif ($items eq "2") { | |
375 | my ($first_address, $last_address) = @values; | |
376 | ||
377 | # Check if the passed binary address is bigger than | |
378 | # the first address and smaler than the last address | |
379 | # (between) the stored network range. | |
380 | if (($bin_address >= $first_address) && ($bin_address <= $last_address)) { | |
381 | # The address is part of an ignored network. | |
382 | $logger->Log("debug", "Address is found inside the ignored network $key."); | |
383 | ||
384 | # Return "1" (True). | |
385 | return 1; | |
386 | } | |
387 | ||
388 | # If the amount is not eighter one or two, the current entry of the ignorehash seems | |
389 | # to be corrupted. Skip and log it. | |
390 | } else { | |
391 | # Write log message about this corruped item in the ignore hash. | |
392 | $logger->Log("err", "Invalid item in the Ignore Hash: $key - @values"); | |
393 | ||
394 | # Skip this element of the ignore hash. | |
395 | next; | |
396 | } | |
397 | } | |
398 | ||
399 | # If we got here, the given address is not part of the ignore hash. | |
400 | # Return nothing (False). | |
401 | return; | |
402 | } | |
403 | ||
df6ec59f | 404 | 1; |