From 240006bdf517df0a72d52efb285fdf9cf8b58d35 Mon Sep 17 00:00:00 2001
From: Roeland Jago Douma <roeland@famdouma.nl>
Date: Mon, 23 Apr 2018 13:48:39 +0200
Subject: [PATCH] When sharing calendars and addressbooks the principal has to
 be verified to be valid

https://github.com/owncloud/core/pull/30149/commits/d3fb8fcdd3a6b00bde0c3c9eb4039876e7fc1967

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>
---
 apps/dav/lib/CalDAV/Calendar.php           |  2 +-
 apps/dav/lib/CardDAV/AddressBook.php       |  2 +-
 apps/dav/lib/Connector/Sabre/Principal.php |  7 +++++++
 apps/dav/lib/DAV/Sharing/Backend.php       | 12 +++++++++---
 4 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/apps/dav/lib/CalDAV/Calendar.php b/apps/dav/lib/CalDAV/Calendar.php
index 02808ab566..a07bbe9321 100644
--- a/apps/dav/lib/CalDAV/Calendar.php
+++ b/apps/dav/lib/CalDAV/Calendar.php
@@ -203,7 +203,7 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IShareable {
 			}
 
 			$this->caldavBackend->updateShares($this, [], [
-				'href' => $principal
+				$principal
 			]);
 			return;
 		}
diff --git a/apps/dav/lib/CardDAV/AddressBook.php b/apps/dav/lib/CardDAV/AddressBook.php
index a034f8b942..7120231987 100644
--- a/apps/dav/lib/CardDAV/AddressBook.php
+++ b/apps/dav/lib/CardDAV/AddressBook.php
@@ -181,7 +181,7 @@ class AddressBook extends \Sabre\CardDAV\AddressBook implements IShareable {
 			}
 
 			$this->carddavBackend->updateShares($this, [], [
-				'href' => $principal
+				$principal
 			]);
 			return;
 		}
diff --git a/apps/dav/lib/Connector/Sabre/Principal.php b/apps/dav/lib/Connector/Sabre/Principal.php
index b2f57cf715..b94b093ab5 100644
--- a/apps/dav/lib/Connector/Sabre/Principal.php
+++ b/apps/dav/lib/Connector/Sabre/Principal.php
@@ -324,6 +324,13 @@ class Principal implements BackendInterface {
 				return $this->principalPrefix . '/' . $user->getUID();
 			}
 		}
+		if (substr($uri, 0, 10) === 'principal:') {
+			$principal = substr($uri, 10);
+			$principal = $this->getPrincipalByPath($principal);
+			if ($principal !== null) {
+				return $principal['uri'];
+			}
+		}
 
 		return null;
 	}
diff --git a/apps/dav/lib/DAV/Sharing/Backend.php b/apps/dav/lib/DAV/Sharing/Backend.php
index 87c094c6d6..433d9db9c0 100644
--- a/apps/dav/lib/DAV/Sharing/Backend.php
+++ b/apps/dav/lib/DAV/Sharing/Backend.php
@@ -67,12 +67,18 @@ class Backend {
 	 * @param string[] $add
 	 * @param string[] $remove
 	 */
-	public function updateShares($shareable, $add, $remove) {
+	public function updateShares(IShareable $shareable, array $add, array $remove) {
 		foreach($add as $element) {
-			$this->shareWith($shareable, $element);
+			$principal = $this->principalBackend->findByUri($element['href'], '');
+			if ($principal !== '') {
+				$this->shareWith($shareable, $element);
+			}
 		}
 		foreach($remove as $element) {
-			$this->unshare($shareable, $element);
+			$principal = $this->principalBackend->findByUri($element, '');
+			if ($principal !== '') {
+				$this->unshare($shareable, $element);
+			}
 		}
 	}