Better check reshare permissions when creating a share

Signed-off-by: Joas Schilling <coding@schilljs.com>

build/integration/features/sharing-v1-part2.feature

@@ -251,6 +251,66 @@ Feature: sharing
     Then the OCS status code should be "404"
     And the HTTP status code should be "200"
 
+  Scenario: User is not allowed to reshare file with additional delete permissions
+  As an "admin"
+    Given user "user0" exists
+    And user "user1" exists
+    And user "user2" exists
+    And As an "user0"
+    And creating a share with
+      | path | /PARENT |
+      | shareType | 0 |
+      | shareWith | user1 |
+      | permissions | 16 |
+    And As an "user1"
+    When creating a share with
+      | path | /PARENT (2) |
+      | shareType | 0 |
+      | shareWith | user2 |
+      | permissions | 25 |
+    Then the OCS status code should be "404"
+    And the HTTP status code should be "200"
+
+  Scenario: User is not allowed to reshare file with additional delete permissions for files
+  As an "admin"
+    Given user "user0" exists
+    And user "user1" exists
+    And user "user2" exists
+    And As an "user0"
+    And creating a share with
+      | path | /textfile0.txt |
+      | shareType | 0 |
+      | shareWith | user1 |
+      | permissions | 16 |
+    And As an "user1"
+    When creating a share with
+      | path | /textfile0 (2).txt |
+      | shareType | 0 |
+      | shareWith | user2 |
+      | permissions | 25 |
+    Then the OCS status code should be "100"
+    And the HTTP status code should be "200"
+    When Getting info of last share
+    Then Share fields of last share match with
+      | id | A_NUMBER |
+      | item_type | file |
+      | item_source | A_NUMBER |
+      | share_type | 0 |
+      | share_with | user2 |
+      | file_source | A_NUMBER |
+      | file_target | /textfile0 (2).txt |
+      | path | /textfile0 (2).txt |
+      | permissions | 17 |
+      | stime | A_NUMBER |
+      | storage | A_NUMBER |
+      | mail_send | 0 |
+      | uid_owner | user1 |
+      | storage_id | shared::/textfile0 (2).txt |
+      | file_parent | A_NUMBER |
+      | share_with_displayname | user2 |
+      | displayname_owner | user1 |
+      | mimetype          | text/plain |
+
   Scenario: Get a share with a user which didn't received the share
     Given user "user0" exists
     And user "user1" exists

lib/private/Share20/Manager.php

@@ -269,11 +269,13 @@ class Manager implements IManager {
 
 		// And you can't share your rootfolder
 		if ($this->userManager->userExists($share->getSharedBy())) {
-			$sharedPath = $this->rootFolder->getUserFolder($share->getSharedBy())->getPath();
+			$userFolder = $this->rootFolder->getUserFolder($share->getSharedBy());
+			$userFolderPath = $userFolder->getPath();
 		} else {
-			$sharedPath = $this->rootFolder->getUserFolder($share->getShareOwner())->getPath();
+			$userFolder = $this->rootFolder->getUserFolder($share->getShareOwner());
+			$userFolderPath = $userFolder->getPath();
 		}
-		if ($sharedPath === $share->getNode()->getPath()) {
+		if ($userFolderPath === $share->getNode()->getPath()) {
 			throw new \InvalidArgumentException('You can’t share your root folder');
 		}
 
@@ -297,6 +299,23 @@ class Manager implements IManager {
 		$mount = $share->getNode()->getMountPoint();
 		if (!($mount instanceof MoveableMount)) {
 			$permissions |= \OCP\Constants::PERMISSION_DELETE | \OCP\Constants::PERMISSION_UPDATE;
+		} else if ($share->getNode()->getOwner()->getUID() !== $share->getSharedBy()) {
+			$userMountPointId = $mount->getStorageRootId();
+			$userMountPoints = $userFolder->getById($userMountPointId);
+			$userMountPoint = array_shift($userMountPoints);
+
+			/* Check if this is an incoming share */
+			$incomingShares = $this->getSharedWith($share->getSharedBy(), Share::SHARE_TYPE_USER, $userMountPoint, -1, 0);
+			$incomingShares = array_merge($incomingShares, $this->getSharedWith($share->getSharedBy(), Share::SHARE_TYPE_GROUP, $userMountPoint, -1, 0));
+			$incomingShares = array_merge($incomingShares, $this->getSharedWith($share->getSharedBy(), Share::SHARE_TYPE_ROOM, $userMountPoint, -1, 0));
+
+			/** @var \OCP\Share\IShare[] $incomingShares */
+			if (!empty($incomingShares)) {
+				$permissions = 0;
+				foreach ($incomingShares as $incomingShare) {
+					$permissions |= $incomingShare->getPermissions();
+				}
+			}
 		}
 
 		// Check that we do not share with more permissions than we have

tests/lib/Share20/ManagerTest.php

@@ -589,6 +589,12 @@ class ManagerTest extends \Test\TestCase {
 		$limitedPermssions->method('getPermissions')->willReturn(\OCP\Constants::PERMISSION_READ);
 		$limitedPermssions->method('getPath')->willReturn('path');
 
+		$owner = $this->createMock(IUser::class);
+		$owner->method('getUID')
+			->willReturn($user0);
+		$limitedPermssions->method('getOwner')
+			->willReturn($owner);
+
 		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_USER,  $limitedPermssions, $user2, $user0, $user0, null, null, null), 'A share requires permissions', true];
 		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_GROUP, $limitedPermssions, $group0, $user0, $user0, null, null, null), 'A share requires permissions', true];
 		$data[] = [$this->createShare(null, \OCP\Share::SHARE_TYPE_LINK,  $limitedPermssions, null, $user0, $user0, null, null, null), 'A share requires permissions', true];