CUPS bannertopdf error with permission denied despite "none" banners

When printing I get "Filter failed". According to the CUPS logs, the banner is set to "none" but still the bannertopdf filter fails with permission denied error output:

D [21/Dec/2020:12:48:31 +0100] [Job 926] PID 88203 (/usr/lib/cups/filter/bannertopdf) stopped with status 1.
...
D [21/Dec/2020:12:48:31 +0100] [Job 926] Error opening banner file: Permission denied
D [21/Dec/2020:12:48:31 +0100] [Job 926] Error: could not read banner file
...

Here the full logs up to the bannertopdf errors:

D [21/Dec/2020:12:48:31 +0100] cupsdSetBusyState: newbusy="Active clients and dirty files", busy="Active clients and dirty files"
D [21/Dec/2020:12:48:31 +0100] [Job 926] Applying default options...
D [21/Dec/2020:12:48:31 +0100] add_job: requesting-user-name="root"
D [21/Dec/2020:12:48:31 +0100] Adding default job-sheets values "none,none"...
I [21/Dec/2020:12:48:31 +0100] [Job 926] Adding start banner page "none".
D [21/Dec/2020:12:48:31 +0100] cupsdMarkDirty(----S)
D [21/Dec/2020:12:48:31 +0100] cupsdSetBusyState: newbusy="Active clients and dirty files", busy="Active clients and dirty files"
D [21/Dec/2020:12:48:31 +0100] cupsdMarkDirty(---J-)
D [21/Dec/2020:12:48:31 +0100] cupsdSetBusyState: newbusy="Active clients and dirty files", busy="Active clients and dirty files"
I [21/Dec/2020:12:48:31 +0100] [Job 926] Adding end banner page "none".
I [21/Dec/2020:12:48:31 +0100] [Job 926] File of type application/vnd.cups-pdf-banner queued by "root".
D [21/Dec/2020:12:48:31 +0100] [Job 926] hold_until=0
I [21/Dec/2020:12:48:31 +0100] [Job 926] Queued on "MFCJ470DW" by "root".
D [21/Dec/2020:12:48:31 +0100] [Job 926] time-at-processing=1608551311
D [21/Dec/2020:12:48:31 +0100] cupsdMarkDirty(---J-)
D [21/Dec/2020:12:48:31 +0100] cupsdSetBusyState: newbusy="Active clients and dirty files", busy="Active clients and dirty files"
D [21/Dec/2020:12:48:31 +0100] cupsdSetBusyState: newbusy="Active clients and dirty files", busy="Active clients and dirty files"
D [21/Dec/2020:12:48:31 +0100] cupsdMarkDirty(----S)
D [21/Dec/2020:12:48:31 +0100] cupsdSetBusyState: newbusy="Active clients and dirty files", busy="Active clients and dirty files"
D [21/Dec/2020:12:48:31 +0100] [Job 926] 4 filters for job:
D [21/Dec/2020:12:48:31 +0100] [Job 926] bannertopdf (application/vnd.cups-pdf-banner to application/pdf, cost 32)
D [21/Dec/2020:12:48:31 +0100] [Job 926] pdftopdf (application/pdf to application/vnd.cups-pdf, cost 66)
D [21/Dec/2020:12:48:31 +0100] [Job 926] pdftops (application/vnd.cups-pdf to application/vnd.cups-postscript, cost 100)
D [21/Dec/2020:12:48:31 +0100] [Job 926] brother_lpdwrapper_mfcj470dw (application/vnd.cups-postscript to printer/MFCJ470DW, cost 0)
D [21/Dec/2020:12:48:31 +0100] [Job 926] job-sheets=none,none
D [21/Dec/2020:12:48:31 +0100] [Job 926] argv="MFCJ470DW"
D [21/Dec/2020:12:48:31 +0100] [Job 926] argv="926"
D [21/Dec/2020:12:48:31 +0100] [Job 926] argv="root"
D [21/Dec/2020:12:48:31 +0100] [Job 926] argv="Test Page"
D [21/Dec/2020:12:48:31 +0100] [Job 926] argv="1"
D [21/Dec/2020:12:48:31 +0100] [Job 926] argv="job-uuid=urn:uuid:e7d8c878-3d1a-373a-6205-0ccb7ee4e2dc job-originating-host-name=localhost date-time-at-creation= date-time-at-processing= time-at-creation=1608551311 time-at-processing=1608551311"
D [21/Dec/2020:12:48:31 +0100] [Job 926] argv="/var/spool/cups/d00926-001"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_CACHEDIR=/var/cache/cups"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_DATADIR=/usr/share/cups"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_DOCROOT=/usr/share/cups/doc-root"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_FONTPATH=/usr/share/cups/fonts"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_REQUESTROOT=/var/spool/cups"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_SERVERBIN=/usr/lib/cups"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_SERVERROOT=/etc/cups"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_STATEDIR=/run/cups"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="HOME=/var/spool/cups/tmp"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="PATH=/usr/lib/cups/filter:/usr/bin:/usr/sbin:/bin:/usr/bin"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="SERVER_ADMIN=root@creeck"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="SOFTWARE=CUPS/2.3.1"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="TMPDIR=/var/spool/cups/tmp"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="USER=root"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_MAX_MESSAGE=2047"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_SERVER=/run/cups/cups.sock"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_ENCRYPTION=IfRequested"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="IPP_PORT=631"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CHARSET=utf-8"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="LANG=de.UTF-8"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="PPD=/etc/cups/ppd/MFCJ470DW.ppd"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="RIP_MAX_CACHE=128m"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CONTENT_TYPE=application/vnd.cups-pdf-banner"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="DEVICE_URI=usb:/dev/usb/lp0"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="PRINTER_INFO=MFCJ470DW"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="PRINTER_LOCATION="
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="PRINTER=MFCJ470DW"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="PRINTER_STATE_REASONS=none"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="CUPS_FILETYPE=document"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="FINAL_CONTENT_TYPE=application/vnd.cups-postscript"
D [21/Dec/2020:12:48:31 +0100] [Job 926] envp="AUTH_I****"
I [21/Dec/2020:12:48:31 +0100] [Job 926] Started filter /usr/lib/cups/filter/bannertopdf (PID 88203)
I [21/Dec/2020:12:48:31 +0100] [Job 926] Started filter /usr/lib/cups/filter/pdftopdf (PID 88204)
I [21/Dec/2020:12:48:31 +0100] [Job 926] Started filter /usr/lib/cups/filter/pdftops (PID 88205)
I [21/Dec/2020:12:48:31 +0100] [Job 926] Started filter /usr/lib/cups/filter/brother_lpdwrapper_mfcj470dw (PID 88206)
I [21/Dec/2020:12:48:31 +0100] [Job 926] Started backend /usr/lib/cups/backend/usb (PID 88208)
D [21/Dec/2020:12:48:31 +0100] cupsdMarkDirty(----S)
D [21/Dec/2020:12:48:31 +0100] cupsdSetBusyState: newbusy="Active clients, printing jobs, and dirty files", busy="Active clients and dirty files"
D [21/Dec/2020:12:48:31 +0100] [Client 204] Returning IPP successful-ok for Print-Job (ipp://localhost:631/printers/MFCJ470DW) from localhost.
D [21/Dec/2020:12:48:31 +0100] [Client 204] Content-Length: 190
D [21/Dec/2020:12:48:31 +0100] [Client 204] cupsdSendHeader: code=200, type="application/ipp", auth_type=0
D [21/Dec/2020:12:48:31 +0100] [Job 926] PID 88203 (/usr/lib/cups/filter/bannertopdf) stopped with status 1.
D [21/Dec/2020:12:48:31 +0100] [Client 204] con->http=0x558c6f9ccea0
D [21/Dec/2020:12:48:31 +0100] [Client 204] cupsdWriteClient error=0, used=0, state=HTTP_STATE_POST_SEND, data_encoding=HTTP_ENCODING_LENGTH, data_remaining=190, response=0x558c6fa94730(IPP_STATE_IDLE), pipe_pid=0, file=-1
D [21/Dec/2020:12:48:31 +0100] [Client 204] Writing IPP response, ipp_state=IPP_STATE_DATA, old wused=0, new wused=0
D [21/Dec/2020:12:48:31 +0100] [Client 204] bytes=0, http_state=0, data_remaining=190
D [21/Dec/2020:12:48:31 +0100] [Client 204] Flushing write buffer.
D [21/Dec/2020:12:48:31 +0100] [Client 204] New state is HTTP_STATE_WAITING
D [21/Dec/2020:12:48:31 +0100] [Client 204] Waiting for request.
D [21/Dec/2020:12:48:31 +0100] cupsdSetBusyState: newbusy="Active clients, printing jobs, and dirty files", busy="Active clients, printing jobs, and dirty files"
D [21/Dec/2020:12:48:31 +0100] [Notifier] state=3
D [21/Dec/2020:12:48:31 +0100] [Notifier] state=3
D [21/Dec/2020:12:48:31 +0100] [Notifier] state=3
D [21/Dec/2020:12:48:31 +0100] [Job 926] Error opening banner file: Permission denied
D [21/Dec/2020:12:48:31 +0100] [Job 926] Error: could not read banner file
D [21/Dec/2020:12:48:31 +0100] [Job 926] pdftopdf: Last filter determined by the PPD: brother_lpdwrapper_mfcj470dw; FINAL_CONTENT_TYPE: application/vnd.cups-postscript => pdftopdf will not log pages in page_log.
D [21/Dec/2020:12:48:31 +0100] [Job 926] Input is empty, outputting empty file.
D [21/Dec/2020:12:48:31 +0100] [Job 926] PID 88204 (/usr/lib/cups/filter/pdftopdf) exited with no errors.

The downstream filters (e.g. pdftops) run successfully, though on empty input and with empty output:

D [21/Dec/2020:12:48:31 +0100] [Job 926] pdftops - copying to temp print file \"/tmp/1588d5fec4a35\"
D [21/Dec/2020:12:48:31 +0100] [Job 926] Input is empty, outputting empty file.
D [21/Dec/2020:12:48:31 +0100] [Job 926] PID 88205 (/usr/lib/cups/filter/pdftops) exited with no errors.

The existing banner files are all world-readable (including the complete path), but there is no banner none. Creating an empty file, does not change anything and I guess that no such file is actually necessary. ## Some Background The printer is a Brother MFC-J470DW connected to via USB and network. The same problems occurs when I send the print job via the network. The printer used to work with Ubuntu 19.04, but since an upgrade (not a reinstall) to Ubuntu 20.04.1 LTS (Focal Fossa) it doesn't work anymore. This printer requires the installation of drivers from Brother. In the old Ubuntu installation, these used to be installed with the Brother installer linux-brprinter-installer-2.1.1-1. After the upgrade Brother installer linux-brprinter-installer-2.2.2-1 is used. ## Packages & Versions * I used the printer driver install script linux-brprinter-installer-2.2.2-1, which downloaded and installed * brscan4-0.4.9-1.amd64.deb * brscan-skey-0.3.1-1.amd64.deb * mfcj470dwcupswrapper-3.0.0-1a.i386.deb * mfcj470dwcupswrapper-3.0.0-1.i386.deb * mfcj470dwlpr-3.0.0-1a.i386.deb * mfcj470dwlpr-3.0.0-1.i386.deb * More possibly relevant versions $ dpkg -l hplip "cups*" Gewünscht=Unbekannt/Installieren/R=Entfernen/P=Vollständig Löschen/Halten | Status=Nicht/Installiert/Config/U=Entpackt/halb konFiguriert/ Halb installiert/Trigger erWartet/Trigger anhängig |/ Fehler?=(kein)/R=Neuinstallation notwendig (Status, Fehler: GROSS=schlecht) ||/ Name Version Architektur Beschreibung +++-=========================-================-============-=================================================================== ii cups 2.3.1-9ubuntu1.1 amd64 Common UNIX Printing System(tm) - PPD/driver support, web interface ii cups-browsed 1.27.4-1 amd64 OpenPrinting CUPS Filters - cups-browsed ii cups-bsd 2.3.1-9ubuntu1.1 amd64 Common UNIX Printing System(tm) - BSD commands ii cups-client 2.3.1-9ubuntu1.1 amd64 Common UNIX Printing System(tm) - client programs (SysV) ii cups-common 2.3.1-9ubuntu1.1 all Common UNIX Printing System(tm) - common files ii cups-core-drivers 2.3.1-9ubuntu1.1 amd64 Common UNIX Printing System(tm) - driverless printing ii cups-daemon 2.3.1-9ubuntu1.1 amd64 Common UNIX Printing System(tm) - daemon ii cups-filters 1.27.4-1 amd64 OpenPrinting CUPS Filters - Main Package ii cups-filters-core-drivers 1.27.4-1 amd64 OpenPrinting CUPS Filters - Driverless printing un cups-filters-ippusbxd (keine Beschreibung vorhanden) ii cups-ipp-utils 2.3.1-9ubuntu1.1 amd64 Common UNIX Printing System(tm) - IPP developer/admin utilities un cups-pdf (keine Beschreibung vorhanden) ii cups-pk-helper 0.2.6-1ubuntu3 amd64 PolicyKit helper to configure cups with fine-grained privileges ii cups-ppdc 2.3.1-9ubuntu1.1 amd64 Common UNIX Printing System(tm) - PPD manipulation utilities ii cups-server-common 2.3.1-9ubuntu1.1 all Common UNIX Printing System(tm) - server common files rc hplip 3.20.3+dfsg0-2 amd64 HP Linux Printing and Imaging System (HPLIP)