2 files changed, 24 insertions, 2 deletions
diff --git a/apps/dav/lib/DAV/CustomPropertiesBackend.php b/apps/dav/lib/DAV/CustomPropertiesBackend.php
index f73246161ba..bc3c146875b 100644
--- a/apps/dav/lib/DAV/CustomPropertiesBackend.php
+++ b/apps/dav/lib/DAV/CustomPropertiesBackend.php
@@ -519,7 +519,9 @@ class CustomPropertiesBackend implements BackendInterface {
 			$value = $value->getHref();
 		} else {
 			$valueType = self::PROPERTY_TYPE_OBJECT;
-			$value = serialize($value);
+			// serialize produces null character
+			// these can not be properly stored in some databases and need to be replaced
+			$value = str_replace(chr(0), '\x00', serialize($value));
 		}
 		return [$value, $valueType];
 	}
@@ -534,7 +536,9 @@ class CustomPropertiesBackend implements BackendInterface {
 			case self::PROPERTY_TYPE_HREF:
 				return new Href($value);
 			case self::PROPERTY_TYPE_OBJECT:
-				return unserialize($value);
+				// some databases can not handel null characters, these are custom encoded during serialization
+				// this custom encoding needs to be first reversed before unserializing
+				return unserialize(str_replace('\x00', chr(0), $value));
 			case self::PROPERTY_TYPE_STRING:
 			default:
 				return $value;
diff --git a/apps/dav/tests/unit/DAV/CustomPropertiesBackendTest.php b/apps/dav/tests/unit/DAV/CustomPropertiesBackendTest.php
index 6fc87437fe0..fa71fd8016b 100644
--- a/apps/dav/tests/unit/DAV/CustomPropertiesBackendTest.php
+++ b/apps/dav/tests/unit/DAV/CustomPropertiesBackendTest.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * SPDX-FileCopyrightText: 2017 Nextcloud GmbH and Nextcloud contributors
  * SPDX-License-Identifier: AGPL-3.0-or-later
@@ -458,4 +459,21 @@ class CustomPropertiesBackendTest extends TestCase {
 			[str_repeat('long_path1', 100), str_repeat('long_path2', 100)]
 		];
 	}
+
+	public function testDecodeValueFromDatabaseObjectCurrent(): void {
+		$propertyValue = 'O:48:"Sabre\CalDAV\Xml\Property\ScheduleCalendarTransp":1:{s:8:"\x00*\x00value";s:6:"opaque";}';
+		$propertyType = 3;
+		$decodeValue = $this->invokePrivate($this->backend, 'decodeValueFromDatabase', [$propertyValue, $propertyType]);
+		$this->assertInstanceOf(\Sabre\CalDAV\Xml\Property\ScheduleCalendarTransp::class, $decodeValue);
+		$this->assertEquals('opaque', $decodeValue->getValue());
+	}
+
+	public function testDecodeValueFromDatabaseObjectLegacy(): void {
+		$propertyValue = 'O:48:"Sabre\CalDAV\Xml\Property\ScheduleCalendarTransp":1:{s:8:"' . chr(0) . '*' . chr(0) . 'value";s:6:"opaque";}';
+		$propertyType = 3;
+		$decodeValue = $this->invokePrivate($this->backend, 'decodeValueFromDatabase', [$propertyValue, $propertyType]);
+		$this->assertInstanceOf(\Sabre\CalDAV\Xml\Property\ScheduleCalendarTransp::class, $decodeValue);
+		$this->assertEquals('opaque', $decodeValue->getValue());
+	}
+
 }