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

[Alex Persson]

I just found that it seems to be a bug in CUPS 2.2.7 in Ubuntu 18.04 LTS according to https://bugs.launchpad.net/ubuntu/+source/cups/+bug/1783298

The suggested patch to solve the problem according to the link above that seems to work looks like this:

--- cups-2.2.7.orig/cups/auth.c
+++ cups-2.2.7/cups/auth.c
@@ -1135,7 +1135,6 @@ cups_local_auth(http_t *http)             /* I - HT

   if (http->hostaddr->addr.sa_family == AF_LOCAL &&
       !getenv("GATEWAY_INTERFACE") &&  /* Not via CGI programs... */
-      cups_auth_find(www_auth, "PeerCred"))
   {
    /*
     * Verify that the current cupsUser() matches the current UID...

Is this a bug that is only in CUPS 2.2.7 coming with Ubuntu 18.04 LTS or is it also a bug in the original CUPS version?

Best, Alex

Alex Persson wrote:

> 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
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