fix(encryption): use the closest cached parent for the access list

build/integration/files_features/encryption.feature

@@ -40,3 +40,62 @@ Feature: encryption
 		Then the command output does not contain the text "server-side encrypted: yes"
 		And Downloading file "/non-encrypted.txt" with range "bytes=0-8"
 		And Downloaded content should be "BLABLABLA"
+
+	Scenario: copy a folder with per-user keys
+		# Setup encryption with per-user keys
+		Given using new dav path
+		And invoking occ with "app:enable encryption"
+		And the command was successful
+		And invoking occ with "encryption:disable-master-key" with input "y"
+		And the command was successful
+		And invoking occ with "encryption:enable"
+		And the command was successful
+		And user "user1" exists
+		And User "user1" created a folder "/source"
+		And User "user1" created a folder "/source/sub"
+		And User "user1" uploads file with content "BLABLABLA" to "/source/sub/encrypted.txt"
+		# The target folders only exist on the storage, not yet in the cache, while the files inside are written
+		When User "user1" copies file "/source" to "/copy"
+		Then the HTTP status code should be "201"
+		And As an "user1"
+		And Downloading file "/copy/sub/encrypted.txt"
+		And Downloaded content should be "BLABLABLA"
+		# Restore the initial encryption state
+		And invoking occ with "encryption:disable"
+		And the command was successful
+		And invoking occ with "encryption:enable-master-key" with input "y"
+		And the command was successful
+
+	Scenario: copy a folder into a shared folder with per-user keys
+		# Setup encryption with per-user keys
+		Given using new dav path
+		And invoking occ with "app:enable encryption"
+		And the command was successful
+		And invoking occ with "encryption:disable-master-key" with input "y"
+		And the command was successful
+		And invoking occ with "encryption:enable"
+		And the command was successful
+		And user "user1" exists
+		And user "user2" exists
+		# Log in once so that the key pair of the share recipient exists
+		And User "user2" uploads file with content "BLABLABLA" to "/init.txt"
+		And User "user1" created a folder "/shared"
+		And User "user1" created a folder "/source"
+		And User "user1" uploads file with content "BLABLABLA" to "/source/encrypted.txt"
+		And as "user1" creating a share with
+			| path | /shared |
+			| shareType | 0 |
+			| shareWith | user2 |
+			| permissions | 31 |
+		And the HTTP status code should be "200"
+		# The share key of the recipient has to be created from the closest known parent
+		When User "user1" copies file "/source" to "/shared/copy"
+		Then the HTTP status code should be "201"
+		And As an "user2"
+		And Downloading file "/shared/copy/encrypted.txt"
+		And Downloaded content should be "BLABLABLA"
+		# Restore the initial encryption state
+		And invoking occ with "encryption:disable"
+		And the command was successful
+		And invoking occ with "encryption:enable-master-key" with input "y"
+		And the command was successful

lib/private/Encryption/File.php

@@ -13,6 +13,8 @@
 use OCP\Cache\CappedMemoryCache;
 use OCP\Encryption\IFile;
 use OCP\Files\IRootFolder;
+use OCP\Files\IUserFolder;
+use OCP\Files\Node;
 use OCP\Files\NotFoundException;
 use OCP\Server;
 use OCP\Share\IManager;
@@ -72,11 +74,14 @@ public function getAccessList($path) {
 		// first get the shares for the parent and cache the result so that we don't
 		// need to check all parents for every file
 		$parent = dirname($ownerPath);
-		$parentNode = $userFolder->get($parent);
 		if (isset($this->cache[$parent])) {
 			$resultForParents = $this->cache[$parent];
 		} else {
-			$resultForParents = $this->shareManager->getAccessList($parentNode);
+			$resultForParents = ['users' => [], 'public' => false, 'remote' => false];
+			$parentNode = $this->getClosestExistingNode($userFolder, $parent);
+			if ($parentNode !== null) {
+				$resultForParents = $this->shareManager->getAccessList($parentNode) + $resultForParents;
+			}
 			$this->cache[$parent] = $resultForParents;
 		}
 		$userIds = array_merge($userIds, $resultForParents['users']);
@@ -107,4 +112,28 @@ public function getAccessList($path) {
 
 		return ['users' => $uniqueUserIds, 'public' => $public];
 	}
+
+	/**
+	 * Get the node for $path, or for its closest ancestor that is known to the cache.
+	 *
+	 * Copying a folder creates the target directories on the storage before their
+	 * cache entries exist, so while the files inside are written the parent path
+	 * can not be resolved yet. As shares only exist on nodes that are in the cache,
+	 * the access list of the closest known ancestor also applies to $path.
+	 *
+	 * @return ?Node null if not even the user folder itself could be resolved
+	 */
+	private function getClosestExistingNode(IUserFolder $userFolder, string $path): ?Node {
+		while (true) {
+			try {
+				return $userFolder->get($path);
+			} catch (NotFoundException) {
+				$parent = dirname($path);
+				if ($parent === $path || $parent === '.') {
+					return null;
+				}
+				$path = $parent;
+			}
+		}
+	}
 }

tests/lib/Encryption/FileTest.php

@@ -0,0 +1,156 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace Test\Encryption;
+
+use OC\Encryption\File;
+use OC\Encryption\Util;
+use OCP\App\IAppManager;
+use OCP\Files\IRootFolder;
+use OCP\Files\IUserFolder;
+use OCP\Files\Node;
+use OCP\Files\NotFoundException;
+use OCP\Share\IManager;
+use PHPUnit\Framework\MockObject\MockObject;
+use Test\TestCase;
+
+class FileTest extends TestCase {
+	private Util&MockObject $util;
+	private IManager&MockObject $shareManager;
+	private IUserFolder&MockObject $userFolder;
+	private File&MockObject $file;
+
+	#[\Override]
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->util = $this->createMock(Util::class);
+		$this->shareManager = $this->createMock(IManager::class);
+		$this->userFolder = $this->createMock(IUserFolder::class);
+
+		$rootFolder = $this->createMock(IRootFolder::class);
+		$rootFolder->method('getUserFolder')
+			->with('user1')
+			->willReturn($this->userFolder);
+
+		$appManager = $this->createMock(IAppManager::class);
+		$appManager->method('isEnabledForUser')
+			->willReturn(false);
+
+		$this->file = $this->getMockBuilder(File::class)
+			->setConstructorArgs([$this->util, $rootFolder, $this->shareManager])
+			->onlyMethods(['getAppManager'])
+			->getMock();
+		$this->file->method('getAppManager')
+			->willReturn($appManager);
+	}
+
+	/**
+	 * Let the util mock resolve every path to $owner and $ownerPath
+	 */
+	private function mockUtil(string $owner, string $ownerPath): void {
+		$this->util->method('getUidAndFilename')
+			->willReturn([$owner, $ownerPath]);
+		$this->util->method('isFile')
+			->willReturn(true);
+		$this->util->method('stripPartialFileExtension')
+			->willReturnArgument(0);
+	}
+
+	public function testGetAccessList(): void {
+		$this->mockUtil('user1', '/files/folder/file.txt');
+
+		$node = $this->createMock(Node::class);
+		$parentNode = $this->createMock(Node::class);
+		$this->userFolder->method('get')
+			->willReturnMap([
+				['/folder/file.txt', $node],
+				['/folder', $parentNode],
+			]);
+
+		$this->shareManager->method('getAccessList')
+			->willReturnCallback(fn (Node $requested) => match ($requested) {
+				$parentNode => ['users' => ['user2'], 'public' => false, 'remote' => false],
+				$node => ['users' => ['user3'], 'public' => true, 'remote' => false],
+			});
+
+		$this->assertSame(
+			['users' => ['user1', 'user2', 'user3'], 'public' => true],
+			$this->file->getAccessList('/user1/files/folder/file.txt')
+		);
+	}
+
+	/**
+	 * Copying a folder creates the target directories on the storage before their
+	 * cache entries exist, so the parent of a file written into it can not be resolved.
+	 */
+	public function testGetAccessListWithUncachedParent(): void {
+		$this->mockUtil('user1', '/files/target/sub');
+
+		$rootNode = $this->createMock(Node::class);
+		$this->userFolder->method('get')
+			->willReturnCallback(function (string $path) use ($rootNode) {
+				if ($path !== '/') {
+					throw new NotFoundException($path);
+				}
+				return $rootNode;
+			});
+
+		$this->shareManager->expects($this->once())
+			->method('getAccessList')
+			->with($rootNode)
+			->willReturn(['users' => ['user2'], 'public' => false, 'remote' => false]);
+
+		$this->assertSame(
+			['users' => ['user1', 'user2'], 'public' => false],
+			$this->file->getAccessList('/user1/files/target/sub')
+		);
+	}
+
+	public function testGetAccessListWithoutAnyResolvablePath(): void {
+		$this->mockUtil('user1', '/files/target/sub');
+
+		$this->userFolder->method('get')
+			->willThrowException(new NotFoundException());
+
+		$this->shareManager->expects($this->never())
+			->method('getAccessList');
+
+		$this->assertSame(
+			['users' => ['user1'], 'public' => false],
+			$this->file->getAccessList('/user1/files/target/sub')
+		);
+	}
+
+	public function testGetAccessListCachesTheParentResult(): void {
+		$this->util->method('getUidAndFilename')
+			->willReturnCallback(fn (string $path) => ['user1', substr($path, strlen('/user1'))]);
+		$this->util->method('isFile')
+			->willReturn(true);
+		$this->util->method('stripPartialFileExtension')
+			->willReturnArgument(0);
+
+		$parentNode = $this->createMock(Node::class);
+		$this->userFolder->method('get')
+			->willReturnCallback(function (string $path) use ($parentNode) {
+				if ($path !== '/folder') {
+					throw new NotFoundException($path);
+				}
+				return $parentNode;
+			});
+
+		$this->shareManager->expects($this->once())
+			->method('getAccessList')
+			->with($parentNode)
+			->willReturn(['users' => ['user2'], 'public' => false, 'remote' => false]);
+
+		$expected = ['users' => ['user1', 'user2'], 'public' => false];
+		$this->assertSame($expected, $this->file->getAccessList('/user1/files/folder/first.txt'));
+		$this->assertSame($expected, $this->file->getAccessList('/user1/files/folder/second.txt'));
+	}
+}