Do not show room names when the user is not part of it

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

lib/Share/Helper/ShareAPIController.php

@@ -91,25 +91,32 @@ class ShareAPIController {
 			return $result;
 		}
 
-		// The display name of one-to-one rooms is set to the display name of
-		// the other participant, except on reshares to rooms that the user is
-		// not invited to, in which case the display name of both participants
-		// is used.
 		$roomName = $room->getName();
-		if ($room->getType() === Room::ONE_TO_ONE_CALL) {
-			$userIds = $room->getParticipantUserIds();
-			foreach ($userIds as $userId) {
-				if ($this->userId !== $userId) {
+		try {
+			$room->getParticipant($this->userId);
+
+			if ($room->getType() === Room::ONE_TO_ONE_CALL) {
+				$userIds = $room->getParticipantUserIds();
+				foreach ($userIds as $userId) {
+					if ($this->userId === $userId) {
+						continue;
+					}
+
 					$user = $this->userManager->get($userId);
 					if ($user instanceof IUser) {
-						$roomName = $roomName? $roomName . $this->l->t(', ') . $user->getDisplayName(): $user->getDisplayName();
+						$roomName = $user->getDisplayName();
+						break;
 					}
 				}
+			} else if ($roomName === '') {
+				$roomName = $this->l->t('Unnamed conversation');
 			}
+		} catch (ParticipantNotFoundException $e) {
+			// Do not leak the name of rooms the user is not a part of
+			$roomName = $this->l->t('Private conversation');
 		}
 
 		$result['share_with_displayname'] = $roomName;
-
 		if ($room->getType() === Room::PUBLIC_CALL) {
 			$result['token'] = $share->getToken();
 		}

tests/integration/features/sharing/get.feature

@@ -320,7 +320,7 @@ Feature: get
       | storage_id             | home::participant1 |
       | file_target            | /welcome (2).txt |
       | share_with             | one-to-one room not invited to |
-      | share_with_displayname | participant3-displayname, participant4-displayname |
+      | share_with_displayname | Private conversation|
 
   Scenario: get all shares and reshares of a user who reshared a file to an owned one-to-one room
     Given user "participant2" creates room "one-to-one room not invited to"
@@ -354,7 +354,7 @@ Feature: get
       | storage_id             | home::participant1 |
       | file_target            | /welcome (2).txt |
       | share_with             | one-to-one room not invited to |
-      | share_with_displayname | participant2-displayname, participant3-displayname |
+      | share_with_displayname | Private conversation |
 
   Scenario: get all shares and reshares of a user who reshared a file to a one-to-one room
     Given user "participant2" creates room "one-to-one room not invited to"
@@ -388,7 +388,7 @@ Feature: get
       | storage_id             | home::participant1 |
       | file_target            | /welcome (2).txt |
       | share_with             | one-to-one room not invited to |
-      | share_with_displayname | participant2-displayname, participant3-displayname |
+      | share_with_displayname | Private conversation |
 
   Scenario: get all shares of a file
     Given user "participant1" creates room "own group room"
@@ -527,7 +527,7 @@ Feature: get
       | storage_id             | home::participant1 |
       | file_target            | /welcome (2).txt |
       | share_with             | one-to-one room not invited to |
-      | share_with_displayname | participant3-displayname, participant4-displayname |
+      | share_with_displayname | Private conversation |
 
   Scenario: get all shares and reshares of a file reshared to a one-to-one room by its owner
     Given user "participant2" creates room "one-to-one room not invited to"
@@ -561,7 +561,7 @@ Feature: get
       | storage_id             | home::participant1 |
       | file_target            | /welcome (2).txt |
       | share_with             | one-to-one room not invited to |
-      | share_with_displayname | participant2-displayname, participant3-displayname |
+      | share_with_displayname | Private conversation |
 
   Scenario: get all shares and reshares of a file reshared to a one-to-one room by its second participant
     Given user "participant2" creates room "one-to-one room not invited to"
@@ -595,7 +595,7 @@ Feature: get
       | storage_id             | home::participant1 |
       | file_target            | /welcome (2).txt |
       | share_with             | one-to-one room not invited to |
-      | share_with_displayname | participant2-displayname, participant3-displayname |
+      | share_with_displayname | Private conversation |
 
   Scenario: get all shares and reshares of a deleted file
     Given user "participant1" creates room "own group room"