3 files changed, 42 insertions, 0 deletions

diff --git a/lib/private/Files/Storage/Wrapper/Encryption.php b/lib/private/Files/Storage/Wrapper/Encryption.php
index ba23f3c43ec..bdaba57687a 100644
--- a/lib/private/Files/Storage/Wrapper/Encryption.php
+++ b/lib/private/Files/Storage/Wrapper/Encryption.php
@@ -18,6 +18,7 @@ use OC\Files\Storage\Common;
 use OC\Files\Storage\LocalTempFileTrait;
 use OC\Memcache\ArrayCache;
 use OCP\Cache\CappedMemoryCache;
+use OCP\Encryption\Exceptions\InvalidHeaderException;
 use OCP\Encryption\IFile;
 use OCP\Encryption\IManager;
 use OCP\Encryption\Keys\IStorage;
@@ -344,6 +345,16 @@ class Encryption extends Wrapper {
 			if ($shouldEncrypt === true && $encryptionModule !== null) {
 				$this->encryptedPaths->set($this->util->stripPartialFileExtension($path), true);
 				$headerSize = $this->getHeaderSize($path);
+				if ($mode === 'r' && $headerSize === 0) {
+					$firstBlock = $this->readFirstBlock($path);
+					if (!$firstBlock) {
+						throw new InvalidHeaderException("Unable to get header block for $path");
+					} elseif (!str_starts_with($firstBlock, Util::HEADER_START)) {
+						throw new InvalidHeaderException("Unable to get header size for $path, file doesn't start with encryption header");
+					} else {
+						throw new InvalidHeaderException("Unable to get header size for $path, even though file does start with encryption header");
+					}
+				}
 				$source = $this->storage->fopen($path, $mode);
 				if (!is_resource($source)) {
 					return false;
@@ -894,4 +905,16 @@ class Encryption extends Wrapper {
 	public function setEnabled(bool $enabled): void {
 		$this->enabled = $enabled;
 	}
+
+	/**
+	 * Check if the on-disk data for a file has a valid encrypted header
+	 *
+	 * @param string $path
+	 * @return bool
+	 */
+	public function hasValidHeader(string $path): bool {
+		$firstBlock = $this->readFirstBlock($path);
+		$header = $this->util->parseRawHeader($firstBlock);
+		return (count($header) > 0);
+	}
 }
diff --git a/lib/private/Files/Storage/Wrapper/Quota.php b/lib/private/Files/Storage/Wrapper/Quota.php
index 3be77ba1b37..35a265f8c8e 100644
--- a/lib/private/Files/Storage/Wrapper/Quota.php
+++ b/lib/private/Files/Storage/Wrapper/Quota.php
@@ -21,6 +21,7 @@ class Quota extends Wrapper {
 	protected string $sizeRoot;
 	private SystemConfig $config;
 	private bool $quotaIncludeExternalStorage;
+	private bool $enabled = true;
 
 	/**
 	 * @param array $parameters
@@ -46,6 +47,9 @@ class Quota extends Wrapper {
 	}
 
 	private function hasQuota(): bool {
+		if (!$this->enabled) {
+			return false;
+		}
 		return $this->getQuota() !== FileInfo::SPACE_UNLIMITED;
 	}
 
@@ -197,4 +201,8 @@ class Quota extends Wrapper {
 
 		return parent::touch($path, $mtime);
 	}
+
+	public function enableQuota(bool $enabled): void {
+		$this->enabled = $enabled;
+	}
 }
diff --git a/lib/private/Files/View.php b/lib/private/Files/View.php
index f17ced1611b..e49043355e8 100644
--- a/lib/private/Files/View.php
+++ b/lib/private/Files/View.php
@@ -10,6 +10,7 @@ namespace OC\Files;
 use Icewind\Streams\CallbackWrapper;
 use OC\Files\Mount\MoveableMount;
 use OC\Files\Storage\Storage;
+use OC\Files\Storage\Wrapper\Quota;
 use OC\Share\Share;
 use OC\User\LazyUser;
 use OC\User\Manager as UserManager;
@@ -1578,12 +1579,22 @@ class View {
 						// Create parent folders if the mountpoint is inside a subfolder that doesn't exist yet
 						if (!isset($files[$entryName])) {
 							try {
+								[$storage, ] = $this->resolvePath($path . '/' . $entryName);
+								// make sure we can create the mountpoint folder, even if the user has a quota of 0
+								if ($storage->instanceOfStorage(Quota::class)) {
+									$storage->enableQuota(false);
+								}
+
 								if ($this->mkdir($path . '/' . $entryName) !== false) {
 									$info = $this->getFileInfo($path . '/' . $entryName);
 									if ($info !== false) {
 										$files[$entryName] = $info;
 									}
 								}
+
+								if ($storage->instanceOfStorage(Quota::class)) {
+									$storage->enableQuota(true);
+								}
 							} catch (\Exception $e) {
 								// Creating the parent folder might not be possible, for example due to a lack of permissions.
 								$this->logger->debug('Failed to create non-existent parent', ['exception' => $e, 'path' => $path . '/' . $entryName]);