Prevent updates between multiple major versions

Ref https://github.com/owncloud/core/issues/11078

1 files changed, 23 insertions, 1 deletions

diff --git a/lib/private/updater.php b/lib/private/updater.php
index 1d52f9be374..a2aa8bf33e9 100644
--- a/lib/private/updater.php
+++ b/lib/private/updater.php
@@ -146,15 +146,37 @@ class Updater extends BasicEmitter {
 	}
 
 	/**
+	 * Whether an upgrade to a specified version is possible
+	 * @param string $oldVersion
+	 * @param string $newVersion
+	 * @return bool
+	 */
+	public function isUpgradePossible($oldVersion, $newVersion) {
+		$oldVersion = explode('.', $oldVersion);
+		$newVersion = explode('.', $newVersion);
+
+		if($newVersion[0] > ($oldVersion[0] + 1) || $oldVersion[0] > $newVersion[0]) {
+			return false;
+		}
+		return true;
+	}
+
+	/**
 	 * runs the update actions in maintenance mode, does not upgrade the source files
 	 * except the main .htaccess file
 	 *
 	 * @param string $currentVersion current version to upgrade to
 	 * @param string $installedVersion previous version from which to upgrade from
 	 *
+	 * @throws \Exception
 	 * @return bool true if the operation succeeded, false otherwise
 	 */
 	private function doUpgrade($currentVersion, $installedVersion) {
+		// Stop update if the update is over several major versions
+		if (!self::isUpgradePossible($installedVersion, $currentVersion)) {
+			throw new \Exception('Updates between multiple major versions are unsupported.');
+		}
+
 		// Update htaccess files for apache hosts
 		if (isset($_SERVER['SERVER_SOFTWARE']) && strstr($_SERVER['SERVER_SOFTWARE'], 'Apache')) {
 			\OC_Setup::updateHtaccess();
@@ -235,7 +257,7 @@ class Updater extends BasicEmitter {
 	}
 
 	/**
-	 * @param string $version the oc version to check app compatibilty with
+	 * @param string $version the oc version to check app compatibility with
 	 */
 	protected function checkAppUpgrade($version) {
 		$apps = \OC_App::getEnabledApps();