128 lines
3.2 KiB
PHP
128 lines
3.2 KiB
PHP
<?php
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namespace App\Classes\Protocol\DNS;
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use Illuminate\Support\Collection;
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use Illuminate\Support\Facades\Log;
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final class Query
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{
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private const LOGKEY = 'PDQ';
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private string $buf;
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private int $class;
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private string $dns;
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private int $id;
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private int $type;
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private int $arcount;
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private int $qdcount;
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private RR $additional;
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private Collection $labels;
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// https://github.com/guyinatuxedo/dns-fuzzer/blob/master/dns.md
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private const header = [ // Struct of a DNS query
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'id' => [0x00,'n',1], // ID
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'header' => [0x01,'n',1], // Header
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'qdcount' => [0x02,'n',1], // Entries in the question
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'ancount' => [0x03,'n',1], // Resource Records in the answer
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'nscount' => [0x04,'n',1], // Server Resource Records in the answer
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'arcount' => [0x05,'n',1], // Resource Records in the addition records section
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];
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public function __construct(string $buf)
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{
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$this->buf = $buf;
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$rx_ptr = 0;
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// DNS Query header
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$header = unpack(self::unpackheader(self::header),$buf);
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$rx_ptr += $this->header_len();
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$this->id = $header['id'];
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$this->qdcount = $header['qdcount'];
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$this->arcount = $header['arcount'];
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$this->header = $header['header'];
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// Get the domain elements
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$this->labels = collect();
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while (($len=ord(substr($this->buf,$rx_ptr++,1))) !== 0x00) {
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$this->labels->push(strtolower(substr($this->buf,$rx_ptr,$len)));
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$rx_ptr += $len;
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}
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// Get the query type/class
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try {
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$result = unpack('ntype/nclass',substr($this->buf,$rx_ptr,4));
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} catch (\Exception $e) {
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Log::error(sprintf('%s:! Unpack failed: Buffer: [%s] (%d), RXPTR [%d]',self::LOGKEY,hex_dump($this->buf),strlen($this->buf),$rx_ptr));
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throw $e;
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}
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$rx_ptr += 4;
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$this->type = $result['type'];
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$this->class = $result['class'];
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$this->dns = substr($this->buf,$this->header_len(),$rx_ptr-$this->header_len());
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// Do we have additional records
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if ($this->arcount) {
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// Additional records, EDNS: https://datatracker.ietf.org/doc/html/rfc6891
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if (($haystack = strstr(substr($this->buf,$rx_ptr+1+10),"\x00",true)) !== FALSE) {
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Log::error(sprintf('%s:! DNS additional record format error?',self::LOGKEY),['buf'=>hex_dump($this->buf)]);
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return;
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}
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$this->additional = new RR(substr($this->buf,$rx_ptr,(strlen($haystack) === 0) ? NULL : strlen($haystack)));
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$rx_ptr += $this->additional->length;
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}
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if (strlen($this->buf) !== $rx_ptr)
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throw new \Exception(sprintf('! DNS Buffer still has [%d]: %s',strlen($this->buf)-$rx_ptr,hex_dump(substr($this->buf,$rx_ptr))));
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}
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public function __get($key)
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{
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switch ($key) {
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case 'class':
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case 'dns':
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case 'id':
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case 'labels':
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case 'qdcount':
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case 'arcount':
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case 'header':
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case 'type':
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return $this->{$key};
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case 'domain':
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return $this->labels->join('.');
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}
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}
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public static function header_len()
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{
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return collect(self::header)->sum(function($item) { return $item[2]*2; });
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}
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/**
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* Unpack our configured DNS header
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*
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* @param array $pack
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* @return string
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*/
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protected static function unpackheader(array $pack): string
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{
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return join('/',
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collect($pack)
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->sortBy(function($k,$v) {return $k[0];})
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->transform(function($k,$v) {return $k[1].$v;})
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->values()
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->toArray()
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);
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}
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} |