[Bug]: file_exists(): open_basedir restriction in effect. File(/files) is not within the allowed path

⚠️ 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

Log is flooded with

file_exists(): open_basedir restriction in effect. File(/files) is not within the allowed path(s): (/abc/:/tmp/:/proc/) at /abc/xyz/nextcloud/3rdparty/sabre/dav/lib/DAV/FS/Directory.php#78

Steps to reproduce

1. Open Logs

Expected behavior

Use correct path like /remote.php/dav/files, not /files

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

MariaDB

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

Upgraded to a MAJOR version (ex. 22 to 23)

Are you using the Nextcloud Server Encryption module?

None

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 response

Nextcloud Logs

{"reqId":"NYbARyfFtjdAaEfIAvif","level":3,"time":"2023-07-31T08:13:34+00:00","remoteAddr":"141.88.235.123","user":"--","app":"PHP","method":"OPTIONS","url":"/remote.php/dav/files/ttt/","message":"file_exists(): open_basedir restriction in effect. File(/files) is not within the allowed path(s): (/dfgh/:/tmp/:/proc/) at /var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/FS/Directory.php#78","userAgent":"Microsoft Office Excel","version":"27.0.1.2","data":{"app":"PHP"}}
{"reqId":"7BUNPLXkF9LcO3rk7WfQ","level":3,"time":"2023-07-31T08:13:35+00:00","remoteAddr":"141.88.235.123","user":"--","app":"PHP","method":"HEAD","url":"/remote.php/dav/files/ttt/ppp.xlsx","message":"file_exists(): open_basedir restriction in effect. File(/files) is not within the allowed path(s): (/dfgh/:/tmp/:/proc/) at /var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/FS/Directory.php#78","userAgent":"Microsoft Office Existence Discovery","version":"27.0.1.2","data":{"app":"PHP"}}
{"reqId":"7BUNPLXkF9LcO3rk7WfQ","level":3,"time":"2023-07-31T08:13:35+00:00","remoteAddr":"141.88.235.123","user":"--","app":"PHP","method":"HEAD","url":"/remote.php/dav/files/ttt/ppp.xlsx","message":"file_exists(): open_basedir restriction in effect. File(/files) is not within the allowed path(s): (/dfgh/:/tmp/:/proc/) at /var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/FS/Directory.php#78","userAgent":"Microsoft Office Existence Discovery","version":"27.0.1.2","data":{"app":"PHP"}}
{"reqId":"X1C1YQXJxZwHuIdsktnX","level":0,"time":"2023-07-31T08:13:35+00:00","remoteAddr":"141.88.235.123","user":"FFFFF","app":"webdav","method":"PROPFIND","url":"/remote.php/dav/files/ttt/~%24ppp.xlsx","message":"File with name /ttt/~$ppp.xlsx could not be located","userAgent":"Microsoft-WebDAV-MiniRedir/10.0.19045","version":"27.0.1.2","exception":{"Exception":"Sabre\\DAV\\Exception\\NotFound","Message":"File with name /ttt/~$ppp.xlsx could not be located","Code":0,"Trace":[{"file":"/var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/Tree.php","line":78,"function":"getChild","class":"OCA\\DAV\\Connector\\Sabre\\Directory","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":971,"function":"getNodeForPath","class":"Sabre\\DAV\\Tree","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":1662,"function":"getPropertiesIteratorForPath","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":1647,"function":"writeMultiStatus","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/CorePlugin.php","line":346,"function":"generateMultiStatus","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php","line":89,"function":"httpPropFind","class":"Sabre\\DAV\\CorePlugin","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":472,"function":"emit","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":253,"function":"invokeMethod","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":321,"function":"start","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/apps/dav/lib/Server.php","line":364,"function":"exec","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/apps/dav/appinfo/v2/remote.php","line":35,"function":"exec","class":"OCA\\DAV\\Server","type":"->"},{"file":"/var/www/vhosts/abc/nextcloud/remote.php","line":172,"args":["/var/www/vhosts/abc/nextcloud/apps/dav/appinfo/v2/remote.php"],"function":"require_once"}],"File":"/var/www/vhosts/abc/nextcloud/apps/dav/lib/Connector/Sabre/Directory.php","Line":227,"message":"File with name /yyy.xlsx could not be located","exception":{},"CustomMessage":"File with name /yyy.xlsx could not be located"}}

Additional info

There was an older closed bug report here: https://github.com/nextcloud/server/issues/30479

Start with 3rdparty/sabre/dav/lib/DAV/FS/Directory.php at line 78 and apps/dav/lib/Connector/Sabre/Directory.php at line 227. Reproduce the warning using the reported OPTIONS, HEAD, and PROPFIND requests under the shown open_basedir settings, then verify that DAV requests no longer log the invalid /files path warning.