[Bug]: DAV Propfind: Undefined variable $response

[simonspa]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

On NC 27.1.5, some code seems to be able to trigger an issue with DAV propfind:

{"reqId":"v1UAVvIC6fcqsJ6MXg1X","level":3,"time":"2024-01-04T08:35:53+01:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Undefined variable $response at /var/www/nextcloud/lib/private/Files/Storage/DAV.php#305","userAgent":"--","version":"27.1.5.1","data":{"app":"PHP"},"id":"65966804c36da"}

Guessing from the periodicity in the logs this could be triggered by a background job and a federated share. The only federated shares I have run a NC 27.1.2 server on the other end.

I tried to understand the code on question (https://github.com/nextcloud/server/blob/master/lib/private/Files/Storage/DAV.php#L299) but I don't fully grasp it - there seem to be too many possibilities of reaching return $response without ever setting $response - this might be my PHP ignorance though.

This seems to be similar to #16808 but a different error condition.

Steps to reproduce

1. Check logs
2. See error

Expected behavior

No error in logs, or at least clear backttrace/logging of issue

Installation method

Community Manual installation with Archive

Nextcloud Server version

27

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.1

Web server

Nginx

Database engine version

MySQL

Is this bug present after an update or on a fresh install?

Updated from a MINOR version (ex. 22.1 to 22.2)

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

No response

List of activated Apps

No response

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

{"reqId":"v1UAVvIC6fcqsJ6MXg1X","level":3,"time":"2024-01-04T08:35:53+01:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Undefined variable $response at /var/www/nextcloud/lib/private/Files/Storage/DAV.php#305","userAgent":"--","version":"27.1.5.1","data":{"app":"PHP"},"id":"65966c709f6d5"}

Additional info

No response

[solracsf]

Duplicate of #11140 ?

[simonspa]

Good question - I think it is related but not a duplicate. The linked issue refers to public function hasUpdated in line 855 while this error emanates from protected function propfind.

Might still be related since the hasUpdated method calls propfind here.

[alexeyvolkoff]

Hi everyone,
am I facing the same bug? I'm trying to mount an external WebDAV storage

Undefined variable $response at /var/www/html/lib/private/Files/Storage/DAV.php#305
{"reqId":"3rtm1jUw7HaU4BCTKjhA","level":3,"time":"2024-06-25T15:11:45+00:00","remoteAddr":"193.77.124.122","user":"admin","app":"PHP","method":"PUT","url":"/apps/files_external/userstorages/2","message":"Undefined variable $response at /var/www/html/lib/private/Files/Storage/DAV.php#305","userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36","version":"29.0.2.2","data":{"app":"PHP"},"id":"667ae027a81ca"}

[alexeyvolkoff]

here is the response I send to propfind request:

propfind response "<?xml version=\"1.0\" encoding=UTF-8?>\n<D:multistatus xmlns:D=\"DAV:\">\n<D:response>\n<D:href>/</D:href>\n<D:propstat>\n<D:prop>\n<D:getlastmodified>Tue, 25 Jun 2024 16:34:22 GMT</D:getlastmodified>\n<D:getcontenttype>httpd/unix-directory</D:getcontenttype>\n<D:resourcetype>\n<D:collection/>\n</D:resourcetype>\n<D:getetag>\"f48ec06c4f93001e27543ee0abd65b42\"</D:getetag>\n<D:quota-available-bytes>5160385028845206400</D:quota-available-bytes>\n</D:prop>\n<D:status>HTTP/1.1 200 OK</D:status>\n</D:propstat>\n</D:response>\n</D:multistatus>\n"

Looks OK, but DAV client (lib/private/Files/Storage/DAV.php#305) reports undefined response

[susnux]

If you experience this bug, please enable debug log level. There should be a log entry with debug level and app = files_external directly before this error log message. We need that message to proceed here.

[skjnldsv]

Duplicate of #11140 ?

Yes, same errored line