2 files changed, 27 insertions, 63 deletions

diff --git a/lib/private/TempManager.php b/lib/private/TempManager.php
index 68a53f493db..e63b1b32794 100644
--- a/lib/private/TempManager.php
+++ b/lib/private/TempManager.php
@@ -10,6 +10,7 @@ namespace OC;
 use bantu\IniGetWrapper\IniGetWrapper;
 use OCP\IConfig;
 use OCP\ITempManager;
+use OCP\Security\ISecureRandom;
 use Psr\Log\LoggerInterface;
 
 class TempManager implements ITempManager {
@@ -34,51 +35,25 @@ class TempManager implements ITempManager {
 		$this->tmpBaseDir = $this->getTempBaseDir();
 	}
 
-	/**
-	 * Builds the filename with suffix and removes potential dangerous characters
-	 * such as directory separators.
-	 *
-	 * @param string $absolutePath Absolute path to the file / folder
-	 * @param string $postFix Postfix appended to the temporary file name, may be user controlled
-	 * @return string
-	 */
-	private function buildFileNameWithSuffix($absolutePath, $postFix = '') {
+	private function generateTemporaryPath(string $postFix): string {
+		$secureRandom = \OCP\Server::get(ISecureRandom::class);
+		$absolutePath = $this->tmpBaseDir . '/' . self::TMP_PREFIX . $secureRandom->generate(32, ISecureRandom::CHAR_ALPHANUMERIC);
+
 		if ($postFix !== '') {
 			$postFix = '.' . ltrim($postFix, '.');
 			$postFix = str_replace(['\\', '/'], '', $postFix);
-			$absolutePath .= '-';
 		}
 
 		return $absolutePath . $postFix;
 	}
 
-	/**
-	 * Create a temporary file and return the path
-	 *
-	 * @param string $postFix Postfix appended to the temporary file name
-	 * @return string
-	 */
-	public function getTemporaryFile($postFix = '') {
-		if (is_writable($this->tmpBaseDir)) {
-			// To create an unique file and prevent the risk of race conditions
-			// or duplicated temporary files by other means such as collisions
-			// we need to create the file using `tempnam` and append a possible
-			// postfix to it later
-			$file = tempnam($this->tmpBaseDir, self::TMP_PREFIX);
-			$this->current[] = $file;
+	public function getTemporaryFile($postFix = ''): string|false {
+		$path = $this->generateTemporaryPath($postFix);
 
-			// If a postfix got specified sanitize it and create a postfixed
-			// temporary file
-			if ($postFix !== '') {
-				$fileNameWithPostfix = $this->buildFileNameWithSuffix($file, $postFix);
-				touch($fileNameWithPostfix);
-				chmod($fileNameWithPostfix, 0600);
-				$this->current[] = $fileNameWithPostfix;
-				return $fileNameWithPostfix;
-			}
-
-			return $file;
-		} else {
+		$old_umask = umask(0077);
+		$fp = fopen($path, 'x');
+		umask($old_umask);
+		if ($fp === false) {
 			$this->log->warning(
 				'Can not create a temporary file in directory {dir}. Check it exists and has correct permissions',
 				[
@@ -87,30 +62,16 @@ class TempManager implements ITempManager {
 			);
 			return false;
 		}
-	}
 
-	/**
-	 * Create a temporary folder and return the path
-	 *
-	 * @param string $postFix Postfix appended to the temporary folder name
-	 * @return string
-	 */
-	public function getTemporaryFolder($postFix = '') {
-		if (is_writable($this->tmpBaseDir)) {
-			// To create an unique directory and prevent the risk of race conditions
-			// or duplicated temporary files by other means such as collisions
-			// we need to create the file using `tempnam` and append a possible
-			// postfix to it later
-			$uniqueFileName = tempnam($this->tmpBaseDir, self::TMP_PREFIX);
-			$this->current[] = $uniqueFileName;
+		fclose($fp);
+		$this->current[] = $path;
+		return $path;
+	}
 
-			// Build a name without postfix
-			$path = $this->buildFileNameWithSuffix($uniqueFileName . '-folder', $postFix);
-			mkdir($path, 0700);
-			$this->current[] = $path;
+	public function getTemporaryFolder($postFix = ''): string|false {
+		$path = $this->generateTemporaryPath($postFix) . '/';
 
-			return $path . '/';
-		} else {
+		if (mkdir($path, 0700) === false) {
 			$this->log->warning(
 				'Can not create a temporary folder in directory {dir}. Check it exists and has correct permissions',
 				[
@@ -119,6 +80,9 @@ class TempManager implements ITempManager {
 			);
 			return false;
 		}
+
+		$this->current[] = $path;
+		return $path;
 	}
 
 	/**
diff --git a/lib/public/ITempManager.php b/lib/public/ITempManager.php
index 90db91b2ab4..ac8f829f357 100644
--- a/lib/public/ITempManager.php
+++ b/lib/public/ITempManager.php
@@ -16,20 +16,20 @@ interface ITempManager {
 	/**
 	 * Create a temporary file and return the path
 	 *
-	 * @param string $postFix
-	 * @return string
+	 * @param string $postFix Postfix appended to the temporary file name
+	 *
 	 * @since 8.0.0
 	 */
-	public function getTemporaryFile($postFix = '');
+	public function getTemporaryFile(string $postFix = ''): string|false;
 
 	/**
 	 * Create a temporary folder and return the path
 	 *
-	 * @param string $postFix
-	 * @return string
+	 * @param string $postFix Postfix appended to the temporary folder name
+	 *
 	 * @since 8.0.0
 	 */
-	public function getTemporaryFolder($postFix = '');
+	public function getTemporaryFolder(string $postFix = ''): string|false;
 
 	/**
 	 * Remove the temporary files and folders generated during this request