diff --git a/apps/files_sharing/lib/sharedstorage.php b/apps/files_sharing/lib/sharedstorage.php
index e5968aeb06..c7285b1d5c 100644
--- a/apps/files_sharing/lib/sharedstorage.php
+++ b/apps/files_sharing/lib/sharedstorage.php
@@ -299,26 +299,34 @@ class Shared extends \OC\Files\Storage\Common implements ISharedStorage {
 		// we need the paths relative to data/user/files
 		$relPath1 = $this->getMountPoint() . '/' . $path1;
 		$relPath2 = $this->getMountPoint() . '/' . $path2;
+		$pathinfo = pathinfo($relPath1);
 
-		// check for update permissions on the share
-		if ($this->isUpdatable('')) {
-
-			$pathinfo = pathinfo($relPath1);
-			// for part files we need to ask for the owner and path from the parent directory because
-			// the file cache doesn't return any results for part files
-			if (isset($pathinfo['extension']) && $pathinfo['extension'] === 'part') {
-				list($user1, $path1) = \OCA\Files_Sharing\Helper::getUidAndFilename($pathinfo['dirname']);
-				$path1 = $path1 . '/' . $pathinfo['basename'];
-			} else {
-				list($user1, $path1) = \OCA\Files_Sharing\Helper::getUidAndFilename($relPath1);
+		$isPartFile = (isset($pathinfo['extension']) && $pathinfo['extension'] === 'part');
+		$targetExists = $this->file_exists($path2);
+		$sameFolder = (dirname($relPath1) === dirname($relPath2));
+		if ($targetExists || ($sameFolder && !$isPartFile)) {
+			// note that renaming a share mount point is always allowed
+			if (!$this->isUpdatable('')) {
+				return false;
+			}
+		} else {
+			if (!$this->isCreatable('')) {
+				return false;
 			}
-			$targetFilename = basename($relPath2);
-			list($user2, $path2) = \OCA\Files_Sharing\Helper::getUidAndFilename(dirname($relPath2));
-			$rootView = new \OC\Files\View('');
-			return $rootView->rename('/' . $user1 . '/files/' . $path1, '/' . $user2 . '/files/' . $path2 . '/' . $targetFilename);
 		}
 
-		return false;
+		// for part files we need to ask for the owner and path from the parent directory because
+		// the file cache doesn't return any results for part files
+		if ($isPartFile) {
+			list($user1, $path1) = \OCA\Files_Sharing\Helper::getUidAndFilename($pathinfo['dirname']);
+			$path1 = $path1 . '/' . $pathinfo['basename'];
+		} else {
+			list($user1, $path1) = \OCA\Files_Sharing\Helper::getUidAndFilename($relPath1);
+		}
+		$targetFilename = basename($relPath2);
+		list($user2, $path2) = \OCA\Files_Sharing\Helper::getUidAndFilename(dirname($relPath2));
+		$rootView = new \OC\Files\View('');
+		return $rootView->rename('/' . $user1 . '/files/' . $path1, '/' . $user2 . '/files/' . $path2 . '/' . $targetFilename);
 	}
 
 	public function copy($path1, $path2) {
@@ -349,13 +357,25 @@ class Shared extends \OC\Files\Storage\Common implements ISharedStorage {
 				case 'xb':
 				case 'a':
 				case 'ab':
-					$exists = $this->file_exists($path);
-					if ($exists && !$this->isUpdatable($path)) {
+					$creatable = $this->isCreatable($path);
+					$updatable = $this->isUpdatable($path);
+					// if neither permissions given, no need to continue
+					if (!$creatable && !$updatable) {
 						return false;
 					}
-					if (!$exists && !$this->isCreatable(dirname($path))) {
+
+					$exists = $this->file_exists($path);
+					// if a file exists, updatable permissions are required
+					if ($exists && !$updatable) {
 						return false;
 					}
+
+					// part file is allowed if !$creatable but the final file is $updatable
+					if (pathinfo($path, PATHINFO_EXTENSION) !== 'part') {
+						if (!$exists && !$creatable) {
+							return false;
+						}
+					}
 			}
 			$info = array(
 				'target' => $this->getMountPoint() . $path,
diff --git a/apps/files_sharing/tests/sharedstorage.php b/apps/files_sharing/tests/sharedstorage.php
index 4a589a5a73..a8ce92775d 100644
--- a/apps/files_sharing/tests/sharedstorage.php
+++ b/apps/files_sharing/tests/sharedstorage.php
@@ -202,6 +202,158 @@ class Test_Files_Sharing_Storage extends OCA\Files_sharing\Tests\TestCase {
 		$this->assertTrue($result);
 	}
 
+	public function testFopenWithReadOnlyPermission() {
+		$this->view->file_put_contents($this->folder . '/existing.txt', 'foo');
+		$fileinfoFolder = $this->view->getFileInfo($this->folder);
+		$result = \OCP\Share::shareItem('folder', $fileinfoFolder['fileid'], \OCP\Share::SHARE_TYPE_USER,
+			self::TEST_FILES_SHARING_API_USER2, \OCP\Constants::PERMISSION_READ);
+		$this->assertTrue($result);
+
+		self::loginHelper(self::TEST_FILES_SHARING_API_USER2);
+		$user2View = new \OC\Files\View('/' . self::TEST_FILES_SHARING_API_USER2 . '/files');
+
+		// part file should be forbidden
+		$handle = $user2View->fopen($this->folder . '/test.txt.part', 'w');
+		$this->assertFalse($handle);
+
+		// regular file forbidden
+		$handle = $user2View->fopen($this->folder . '/test.txt', 'w');
+		$this->assertFalse($handle);
+
+		// rename forbidden
+		$this->assertFalse($user2View->rename($this->folder . '/existing.txt', $this->folder . '/existing2.txt'));
+
+		// delete forbidden
+		$this->assertFalse($user2View->unlink($this->folder . '/existing.txt'));
+
+		//cleanup
+		self::loginHelper(self::TEST_FILES_SHARING_API_USER1);
+		$result = \OCP\Share::unshare('folder', $fileinfoFolder['fileid'], \OCP\Share::SHARE_TYPE_USER,
+			self::TEST_FILES_SHARING_API_USER2);
+		$this->assertTrue($result);
+	}
+
+	public function testFopenWithCreateOnlyPermission() {
+		$this->view->file_put_contents($this->folder . '/existing.txt', 'foo');
+		$fileinfoFolder = $this->view->getFileInfo($this->folder);
+		$result = \OCP\Share::shareItem('folder', $fileinfoFolder['fileid'], \OCP\Share::SHARE_TYPE_USER,
+			self::TEST_FILES_SHARING_API_USER2, \OCP\Constants::PERMISSION_READ | \OCP\Constants::PERMISSION_CREATE);
+		$this->assertTrue($result);
+
+		self::loginHelper(self::TEST_FILES_SHARING_API_USER2);
+		$user2View = new \OC\Files\View('/' . self::TEST_FILES_SHARING_API_USER2 . '/files');
+
+		// create part file allowed
+		$handle = $user2View->fopen($this->folder . '/test.txt.part', 'w');
+		$this->assertNotFalse($handle);
+		fclose($handle);
+
+		// create regular file allowed
+		$handle = $user2View->fopen($this->folder . '/test-create.txt', 'w');
+		$this->assertNotFalse($handle);
+		fclose($handle);
+
+		// rename file never allowed
+		$this->assertFalse($user2View->rename($this->folder . '/test-create.txt', $this->folder . '/newtarget.txt'));
+		$this->assertFalse($user2View->file_exists($this->folder . '/newtarget.txt'));
+
+		// rename file not allowed if target exists 
+		$this->assertFalse($user2View->rename($this->folder . '/newtarget.txt', $this->folder . '/existing.txt'));
+
+		// overwriting file not allowed
+		$handle = $user2View->fopen($this->folder . '/existing.txt', 'w');
+		$this->assertFalse($handle);
+
+		// overwrite forbidden (no update permission)
+		$this->assertFalse($user2View->rename($this->folder . '/test.txt.part', $this->folder . '/existing.txt'));
+
+		// delete forbidden
+		$this->assertFalse($user2View->unlink($this->folder . '/existing.txt'));
+
+		//cleanup
+		self::loginHelper(self::TEST_FILES_SHARING_API_USER1);
+		$result = \OCP\Share::unshare('folder', $fileinfoFolder['fileid'], \OCP\Share::SHARE_TYPE_USER,
+			self::TEST_FILES_SHARING_API_USER2);
+		$this->assertTrue($result);
+	}
+
+	public function testFopenWithUpdateOnlyPermission() {
+		$this->view->file_put_contents($this->folder . '/existing.txt', 'foo');
+		$fileinfoFolder = $this->view->getFileInfo($this->folder);
+
+		$result = \OCP\Share::shareItem('folder', $fileinfoFolder['fileid'], \OCP\Share::SHARE_TYPE_USER,
+			self::TEST_FILES_SHARING_API_USER2, \OCP\Constants::PERMISSION_READ | \OCP\Constants::PERMISSION_UPDATE);
+		$this->assertTrue($result);
+
+		self::loginHelper(self::TEST_FILES_SHARING_API_USER2);
+		$user2View = new \OC\Files\View('/' . self::TEST_FILES_SHARING_API_USER2 . '/files');
+
+		// create part file allowed
+		$handle = $user2View->fopen($this->folder . '/test.txt.part', 'w');
+		$this->assertNotFalse($handle);
+		fclose($handle);
+
+		// create regular file not allowed
+		$handle = $user2View->fopen($this->folder . '/test-create.txt', 'w');
+		$this->assertFalse($handle);
+
+		// rename part file not allowed to non-existing file
+		$this->assertFalse($user2View->rename($this->folder . '/test.txt.part', $this->folder . '/nonexist.txt'));
+
+		// rename part file allowed to target existing file
+		$this->assertTrue($user2View->rename($this->folder . '/test.txt.part', $this->folder . '/existing.txt'));
+		$this->assertTrue($user2View->file_exists($this->folder . '/existing.txt'));
+
+		// rename regular file allowed
+		$this->assertTrue($user2View->rename($this->folder . '/existing.txt', $this->folder . '/existing-renamed.txt'));
+		$this->assertTrue($user2View->file_exists($this->folder . '/existing-renamed.txt'));
+
+		// overwriting file directly is allowed
+		$handle = $user2View->fopen($this->folder . '/existing-renamed.txt', 'w');
+		$this->assertNotFalse($handle);
+		fclose($handle);
+
+		// delete forbidden
+		$this->assertFalse($user2View->unlink($this->folder . '/existing-renamed.txt'));
+
+		//cleanup
+		self::loginHelper(self::TEST_FILES_SHARING_API_USER1);
+		$result = \OCP\Share::unshare('folder', $fileinfoFolder['fileid'], \OCP\Share::SHARE_TYPE_USER,
+			self::TEST_FILES_SHARING_API_USER2);
+		$this->assertTrue($result);
+	}
+
+	public function testFopenWithDeleteOnlyPermission() {
+		$this->view->file_put_contents($this->folder . '/existing.txt', 'foo');
+		$fileinfoFolder = $this->view->getFileInfo($this->folder);
+		$result = \OCP\Share::shareItem('folder', $fileinfoFolder['fileid'], \OCP\Share::SHARE_TYPE_USER,
+			self::TEST_FILES_SHARING_API_USER2, \OCP\Constants::PERMISSION_READ | \OCP\Constants::PERMISSION_DELETE);
+		$this->assertTrue($result);
+
+		self::loginHelper(self::TEST_FILES_SHARING_API_USER2);
+		$user2View = new \OC\Files\View('/' . self::TEST_FILES_SHARING_API_USER2 . '/files');
+
+		// part file should be forbidden
+		$handle = $user2View->fopen($this->folder . '/test.txt.part', 'w');
+		$this->assertFalse($handle);
+
+		// regular file forbidden
+		$handle = $user2View->fopen($this->folder . '/test.txt', 'w');
+		$this->assertFalse($handle);
+
+		// rename forbidden
+		$this->assertFalse($user2View->rename($this->folder . '/existing.txt', $this->folder . '/existing2.txt'));
+
+		// delete allowed
+		$this->assertTrue($user2View->unlink($this->folder . '/existing.txt'));
+
+		//cleanup
+		self::loginHelper(self::TEST_FILES_SHARING_API_USER1);
+		$result = \OCP\Share::unshare('folder', $fileinfoFolder['fileid'], \OCP\Share::SHARE_TYPE_USER,
+			self::TEST_FILES_SHARING_API_USER2);
+		$this->assertTrue($result);
+	}
+
 	function testMountSharesOtherUser() {
 		$folderInfo = $this->view->getFileInfo($this->folder);
 		$fileInfo = $this->view->getFileInfo($this->filename);
diff --git a/apps/files_trashbin/lib/storage.php b/apps/files_trashbin/lib/storage.php
index 72788aa5ba..3f474d71da 100644
--- a/apps/files_trashbin/lib/storage.php
+++ b/apps/files_trashbin/lib/storage.php
@@ -62,6 +62,22 @@ class Storage extends Wrapper {
 		self::$disableTrash = false;
 	}
 
+	/**
+	 * Rename path1 to path2 by calling the wrapped storage.
+	 *
+	 * @param string $path1 first path
+	 * @param string $path2 second path
+	 */
+	public function rename($path1, $path2) {
+		$result = $this->storage->rename($path1, $path2);
+		if ($result === false) {
+			// when rename failed, the post_rename hook isn't triggered,
+			// but we still want to reenable the trash logic
+			self::$disableTrash = false;
+		}
+		return $result;
+	}
+
 	/**
 	 * Deletes the given file by moving it into the trashbin.
 	 *
diff --git a/lib/private/connector/sabre/objecttree.php b/lib/private/connector/sabre/objecttree.php
index 79ae19522c..999750fd78 100644
--- a/lib/private/connector/sabre/objecttree.php
+++ b/lib/private/connector/sabre/objecttree.php
@@ -175,8 +175,9 @@ class ObjectTree extends \Sabre\DAV\Tree {
 			throw new \Sabre\DAV\Exception\ServiceUnavailable('filesystem not setup');
 		}
 
+		$targetNodeExists = $this->nodeExists($destinationPath);
 		$sourceNode = $this->getNodeForPath($sourcePath);
-		if ($sourceNode instanceof \Sabre\DAV\ICollection and $this->nodeExists($destinationPath)) {
+		if ($sourceNode instanceof \Sabre\DAV\ICollection && $targetNodeExists) {
 			throw new \Sabre\DAV\Exception\Forbidden('Could not copy directory ' . $sourceNode . ', target exists');
 		}
 		list($sourceDir,) = \Sabre\HTTP\URLUtil::splitPath($sourcePath);
@@ -190,14 +191,22 @@ class ObjectTree extends \Sabre\DAV\Tree {
 		}
 
 		try {
-			// check update privileges
-			if (!$this->fileView->isUpdatable($sourcePath) && !$isMovableMount) {
-				throw new \Sabre\DAV\Exception\Forbidden();
-			}
-			if ($sourceDir !== $destinationDir) {
+			$sameFolder = ($sourceDir === $destinationDir);
+			// if we're overwriting or same folder
+			if ($targetNodeExists || $sameFolder) {
+				// note that renaming a share mount point is always allowed
+				if (!$this->fileView->isUpdatable($destinationDir) && !$isMovableMount) {
+					throw new \Sabre\DAV\Exception\Forbidden();
+				}
+			} else {
 				if (!$this->fileView->isCreatable($destinationDir)) {
 					throw new \Sabre\DAV\Exception\Forbidden();
 				}
+			}
+
+			if (!$sameFolder) {
+				// moving to a different folder, source will be gone, like a deletion
+				// note that moving a share mount point is always allowed
 				if (!$this->fileView->isDeletable($sourcePath) && !$isMovableMount) {
 					throw new \Sabre\DAV\Exception\Forbidden();
 				}
diff --git a/tests/lib/connector/sabre/objecttree.php b/tests/lib/connector/sabre/objecttree.php
index d2702027b0..53e53f1e07 100644
--- a/tests/lib/connector/sabre/objecttree.php
+++ b/tests/lib/connector/sabre/objecttree.php
@@ -69,7 +69,7 @@ class ObjectTree extends \Test\TestCase {
 
 	function moveFailedInvalidCharsProvider() {
 		return array(
-			array('a/b', 'a/*', array('a' => false, 'a/b' => true, 'a/c*' => false), array()),
+			array('a/b', 'a/*', array('a' => true, 'a/b' => true, 'a/c*' => false), array()),
 		);
 	}
 
@@ -80,12 +80,12 @@ class ObjectTree extends \Test\TestCase {
 			array('a/b', 'b/b', array('a' => false, 'a/b' => true, 'b' => false, 'b/b' => false), array()),
 			array('a/b', 'b/b', array('a' => true, 'a/b' => true, 'b' => false, 'b/b' => false), array()),
 			array('a/b', 'b/b', array('a' => true, 'a/b' => true, 'b' => true, 'b/b' => false), array('a/b' => false)),
+			array('a/b', 'a/c', array('a' => false, 'a/b' => true, 'a/c' => false), array()),
 		);
 	}
 
 	function moveSuccessProvider() {
 		return array(
-			array('a/b', 'a/c', array('a' => false, 'a/b' => true, 'a/c' => false), array()),
 			array('a/b', 'b/b', array('a' => true, 'a/b' => true, 'b' => true, 'b/b' => false), array('a/b' => true)),
 			// older files with special chars can still be renamed to valid names
 			array('a/b*', 'b/b', array('a' => true, 'a/b*' => true, 'b' => true, 'b/b' => false), array('a/b*' => true)),