Avoid overflow on numeric DB fields while scanning audio files

There are a few integer fields stored to the database which get their
values from the data scanned from the input files: disk, number,
year, length, bitrate.

As we have no control over what kind of data may be scanned from the
files, the values need to be sanitized before entering them to the DB.
If the value wouldn't fit in the numeric limits of the DB field in
question, there would be an unhandled exception and that would break
the scanning process.

refs owncloud#1073

CHANGELOG.md

@@ -16,6 +16,8 @@
 ### Fixed
 - Subsonic: Unhandled exception when attempting to delete a non-existent bookmark
   [#1071](https://github.com/owncloud/music/issues/1071)
+- Scanning breaking if any out-of-bounds numeric value gets scanned from any audio file
+  [#1073](https://github.com/owncloud/music/issues/1073)
 
 ## 1.8.4 - 2023-06-06
 ### Added

lib/Utility/Scanner.php

@@ -9,7 +9,7 @@
  * @author Morris Jobke <hey@morrisjobke.de>
  * @author Pauli Järvinen <pauli.jarvinen@gmail.com>
  * @copyright Morris Jobke 2013, 2014
- * @copyright Pauli Järvinen 2016 - 2021
+ * @copyright Pauli Järvinen 2016 - 2023
  */
 
 namespace OCA\Music\Utility;
@@ -245,12 +245,9 @@ private function extractMetadata(File $file, Folder $libraryRoot, string $filePa
 
 		$meta['picture'] = ExtractorGetID3::getTag($fileInfo, 'picture', true);
 
-		$meta['length'] = $fileInfo['playtime_seconds'] ?? null;
-		if ($meta['length'] !== null) {
-			$meta['length'] = \round($meta['length']);
-		}
+		$meta['length'] = self::normalizeUnsigned($fileInfo['playtime_seconds'] ?? null);
 
-		$meta['bitrate'] = $fileInfo['audio']['bitrate'] ?? null;
+		$meta['bitrate'] = self::normalizeUnsigned($fileInfo['audio']['bitrate'] ?? null);
 
 		return $meta;
 	}
@@ -684,7 +681,7 @@ private function userL10N(string $userId) : IL10N {
 		return $this->l10nFactory->get('music', $languageCode);
 	}
 
-	private static function normalizeOrdinal($ordinal) : ?int {
+	private static function normalizeOrdinal(/*mixed*/ $ordinal) : ?int {
 		if (\is_string($ordinal)) {
 			// convert format '1/10' to '1'
 			$ordinal = \explode('/', $ordinal)[0];
@@ -697,7 +694,7 @@ private static function normalizeOrdinal($ordinal) : ?int {
 			$ordinal = null;
 		}
 
-		return $ordinal;
+		return Util::limit($ordinal, 0, Util::UINT32_MAX);
 	}
 
 	private static function parseFileName(string $fileName) : array {
@@ -713,16 +710,28 @@ private static function parseFileName(string $fileName) : array {
 		}
 	}
 
-	private static function normalizeYear($date) : ?int {
+	private static function normalizeYear(/*mixed*/ $date) : ?int {
+		$year = null;
 		$matches = null;
 
 		if (\ctype_digit($date)) {
-			return (int)$date; // the date is a valid year as-is
+			$year = (int)$date; // the date is a valid year as-is
 		} elseif (\is_string($date) && \preg_match('/^(\d\d\d\d)-\d\d-\d\d.*/', $date, $matches) === 1) {
-			return (int)$matches[1]; // year from ISO-formatted date yyyy-mm-dd
+			$year = (int)$matches[1]; // year from ISO-formatted date yyyy-mm-dd
+		} else {
+			$year = null;
+		}
+
+		return Util::limit($year, Util::SINT32_MIN, Util::SINT32_MAX);
+	}
+
+	private static function normalizeUnsigned(/*mixed*/ $value) : ?int {
+		if (\is_numeric($value)) {
+			$value = (int)\round((float)$value);
 		} else {
-			return null;
+			$value = null;
 		}
+		return Util::limit($value, 0, Util::UINT32_MAX);
 	}
 
 	/**

lib/Utility/Util.php

@@ -7,7 +7,7 @@
  * later. See the COPYING file.
  *
  * @author Pauli Järvinen <pauli.jarvinen@gmail.com>
- * @copyright Pauli Järvinen 2018 - 2021
+ * @copyright Pauli Järvinen 2018 - 2023
  */
 
 namespace OCA\Music\Utility;
@@ -19,6 +19,10 @@
  */
 class Util {
 
+	const UINT32_MAX = 0xFFFFFFFF;
+	const SINT32_MAX = 0x7FFFFFFF;
+	const SINT32_MIN = -self::SINT32_MAX - 1;
+
 	/**
 	 * Map the given array by calling a named member function for each of the array elements
 	 */
@@ -371,4 +375,16 @@ public static function swap(&$a, &$b) : void {
 		$a = $b;
 		$b = $temp;
 	}
+
+	/**
+	 * Limit an integer value between the specified minimum and maximum.
+	 * A null value is a valid input and will produce a null output.
+	 */
+	public static function limit(?int $input, int $min, int $max) : ?int {
+		if ($input === null) {
+			return null;
+		} else {
+			return \max($min, \min($input, $max));
+		}
+	}
 }