[cups] Printing via SMB-Kerberos not working in Ubuntu 18.04

[Alex Persson]

Hello again,

In Ubuntu 18.04 I've now tried to print via SMB-Kerberos through smbspool on the command line and it works!

I've also enabled debugging in cups by setting "LogLevel debug" in /etc/cups/cupsd.conf and by looking at /var/log/cups/error_log I see no attempts to use Kerberos. If I compare to an old Ubuntu 16.04 installation I see lines with SMBSPOOL_KRB5.

Any idea why CUPS don't try printing through SMB-Kerberos? Has "AuthInfoRequired negotiate" in /etc/cups/cupsd.conf changed to something else from version 2.1.3-4ubuntu0.5 (in 16.04) to 2.2.7-1ubuntu2.1 (in 18.04)?

My /etc/cups/printers.conf looks like this for the actual printer:

<DefaultPrinter Myprinter>
UUID urn:uuid:4dba7a2d-2a28-1ead-6d35-4853c3a2fa05
AuthInfoRequired negotiate
Info Myprinter
MakeModel KONICA MINOLTA C658SeriesPS(P)
DeviceURI smb://print-at-my-domain.com/MYPRINTER
State Idle
StateTime 1519999428
ConfigTime 1537621194
Type 8401100
Accepting Yes
Shared No
JobSheets none none
QuotaPeriod 0
PageLimit 0
KLimit 0
OpPolicy default
ErrorPolicy retry-job
</DefaultPrinter>

Thanks in advance, Alex

Alex Persson wrote:

> After upgrading from Ubuntu 16.04 to 18.04 printing via SMB-Kerberos no longer works.
> 
> In 16.04 I can just type "lpr file.pdf", but when doing this in 18.04 I get "Password for [myuser] on localhost?" and it expects me to type my password instead of using my Kerberos ticket for sending the print job to the print queue.
> 
> I have "AuthInfoRequired negotiate" in /etc/cups/printers.conf
> The file /usr/lib/cups/backend/smb is a symbolic link pointing to /usr/lib/x86_64-linux-gnu/samba/smbspool_krb5_wrapper (in 16.04 it was pointing at /usr/bin/smbspool_krb5_wrapper).
> The permission is 700 on /usr/lib/x86_64-linux-gnu/samba/smbspool_krb5_wrapper.
> The version of cups is 2.2.7-1ubuntu2.1 in 18.04 while it was 2.1.3-4ubuntu0.5 in 16.04.
> The version of smbclient is 2:4.7.6+dfsg~ubuntu-0ubuntu2.2 in 18.04 while it was 2:4.3.11+dfsg-0ubuntu0.16.04.16 16.04.
> 
> Can anybody please help me figure out what the problem is?
> 
> Best regards, Alex