Fixes not allowed increasing of link share permissions

Fixes the following:

1. user0 shares folder with user1 (RO but with sharing permissions)
2. user1 shares by link
3. user1 send 'publicUpload=true' OCS request to the link share

before this increased the permissions of the link share. Which should
not happen.

now: API reponds with an error that the permissions can't be increased.

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

2 files changed, 57 insertions, 1 deletions

diff --git a/apps/files_sharing/lib/Controller/ShareAPIController.php b/apps/files_sharing/lib/Controller/ShareAPIController.php
index 1358663ea2b..90274beba49 100644
--- a/apps/files_sharing/lib/Controller/ShareAPIController.php
+++ b/apps/files_sharing/lib/Controller/ShareAPIController.php
@@ -692,6 +692,7 @@ class ShareAPIController extends OCSController {
 
 			if ($newPermissions !== null) {
 				$share->setPermissions($newPermissions);
+				$permissions = $newPermissions;
 			}
 
 			if ($expireDate === '') {
diff --git a/apps/files_sharing/tests/Controller/ShareAPIControllerTest.php b/apps/files_sharing/tests/Controller/ShareAPIControllerTest.php
index 890fdb6eda0..ed4aa1dba9e 100644
--- a/apps/files_sharing/tests/Controller/ShareAPIControllerTest.php
+++ b/apps/files_sharing/tests/Controller/ShareAPIControllerTest.php
@@ -1205,7 +1205,7 @@ class ShareAPIControllerTest extends \Test\TestCase {
 	public function testUpdateLinkShareClear() {
 		$ocs = $this->mockFormatShare();
 
-		$node = $this->getMockBuilder('\OCP\Files\Folder')->getMock();
+		$node = $this->getMockBuilder(Folder::class)->getMock();
 		$share = $this->newShare();
 		$share->setPermissions(\OCP\Constants::PERMISSION_ALL)
 			->setSharedBy($this->currentUser)
@@ -1229,6 +1229,9 @@ class ShareAPIControllerTest extends \Test\TestCase {
 			})
 		)->will($this->returnArgument(0));
 
+		$this->shareManager->method('getSharedWith')
+			->willReturn([]);
+
 		$expected = new DataResponse(null);
 		$result = $ocs->updateShare(42, null, '', 'false', '');
 
@@ -1261,6 +1264,9 @@ class ShareAPIControllerTest extends \Test\TestCase {
 			})
 		)->will($this->returnArgument(0));
 
+		$this->shareManager->method('getSharedWith')
+			->willReturn([]);
+
 		$expected = new DataResponse(null);
 		$result = $ocs->updateShare(42, null, 'password', 'true', '2000-01-01');
 
@@ -1483,6 +1489,9 @@ class ShareAPIControllerTest extends \Test\TestCase {
 			})
 		)->will($this->returnArgument(0));
 
+		$this->shareManager->method('getSharedWith')
+			->willReturn([]);
+
 		$expected = new DataResponse(null);
 		$result = $ocs->updateShare(42, null, null, 'true', null);
 
@@ -1633,6 +1642,52 @@ class ShareAPIControllerTest extends \Test\TestCase {
 		}
 	}
 
+	public function testUpdateShareCannotIncreasePermissionsLinkShare() {
+		$ocs = $this->mockFormatShare();
+
+		$folder = $this->createMock(Folder::class);
+
+		$share = \OC::$server->getShareManager()->newShare();
+		$share
+			->setId(42)
+			->setSharedBy($this->currentUser)
+			->setShareOwner('anotheruser')
+			->setShareType(\OCP\Share::SHARE_TYPE_LINK)
+			->setPermissions(\OCP\Constants::PERMISSION_READ)
+			->setNode($folder);
+
+		// note: updateShare will modify the received instance but getSharedWith will reread from the database,
+		// so their values will be different
+		$incomingShare = \OC::$server->getShareManager()->newShare();
+		$incomingShare
+			->setId(42)
+			->setSharedBy($this->currentUser)
+			->setShareOwner('anotheruser')
+			->setShareType(\OCP\Share::SHARE_TYPE_USER)
+			->setSharedWith('currentUser')
+			->setPermissions(\OCP\Constants::PERMISSION_READ)
+			->setNode($folder);
+
+		$this->shareManager->method('getShareById')->with('ocinternal:42')->willReturn($share);
+
+		$this->shareManager->expects($this->any())
+			->method('getSharedWith')
+			->will($this->returnValueMap([
+				['currentUser', \OCP\Share::SHARE_TYPE_USER, $share->getNode(), -1, 0, [$incomingShare]],
+				['currentUser', \OCP\Share::SHARE_TYPE_GROUP, $share->getNode(), -1, 0, []]
+			]));
+
+		$this->shareManager->expects($this->never())->method('updateShare');
+		$this->shareManager->method('shareApiLinkAllowPublicUpload')->willReturn(true);
+
+		try {
+			$ocs->updateShare(42, null, null, 'true');
+			$this->fail();
+		} catch (OCSNotFoundException $e) {
+			$this->assertEquals('Cannot increase permissions', $e->getMessage());
+		}
+	}
+
 	public function testUpdateShareCanIncreasePermissionsIfOwner() {
 		$ocs = $this->mockFormatShare();