55 lines
1.7 KiB
PHP
55 lines
1.7 KiB
PHP
<?php
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namespace App\Services\Malware;
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final class ArchiveLimitInspector
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{
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public function inspect(string $path): ?string
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{
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$stream = @fopen($path, 'rb');
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if (! is_resource($stream)) {
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return 'archive_inspection_failed';
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}
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$signature = fread($stream, 4);
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fclose($stream);
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if (! is_string($signature) || ! in_array($signature, ["PK\x03\x04", "PK\x05\x06", "PK\x07\x08"], true)) {
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return null;
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}
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if (! class_exists(\ZipArchive::class)) {
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return 'archive_inspector_unavailable';
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}
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$archive = new \ZipArchive;
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if ($archive->open($path, \ZipArchive::RDONLY) !== true) {
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return 'archive_inspection_failed';
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}
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try {
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$maxEntries = max(1, (int) config('services.malware.max_archive_entries', 1000));
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$maxExpandedBytes = max(1, (int) config('services.malware.max_decompressed_bytes', 104857600));
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if ($archive->numFiles > $maxEntries) {
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return 'archive_entry_limit_exceeded';
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}
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$expandedBytes = 0;
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for ($index = 0; $index < $archive->numFiles; $index++) {
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$entry = $archive->statIndex($index);
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if (! is_array($entry) || $entry['size'] < 0) {
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return 'archive_inspection_failed';
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}
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if ($entry['size'] > $maxExpandedBytes - $expandedBytes) {
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return 'archive_decompression_limit';
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}
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$expandedBytes += $entry['size'];
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}
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return null;
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} finally {
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$archive->close();
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}
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}
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}
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