[Samba] FYI: Latest Ubuntu 22.04 hwe kernel update 6.2.0-31 version breaks mount.cifs to vers=1.0 server cifs_mount failed w/return code = -5

[Rowland Penny]

On Mon, 4 Sep 2023 10:50:35 -0400
Michael Lueck via samba <samba at lists.samba.org> wrote:

> Greetings,
> 
> Heads up to the Samba group that I opened the following bug against
> the Ubuntu 22.04 hwe kernel update 6.2.0-31.
> 
> I am thinking it is not due to a SAMBA update as 1) I did not apply a
> SAMBA package update from Ubuntu 22.04 and 2) toggling the version of
> the kernel I boot to causes / corrects the SAMBA mount issue.
> Hopefully soon the Ubuntu team will respond.
> 
> "Ubuntu 22.04 update to 6.2.0-31 kernel version breaks mount.cifs to
> vers=1.0 server cifs_mount failed w/return code = -5"
> https://bugs.launchpad.net/bugs/2034033
> 
> The following versions are the existing/working version:
> 
> linux-image-6.2.0-26-generic                  6.2.0-26.26~22.04.1
> 
> And the updated/not working version:
> 
> linux-image-6.2.0-31-generic                  6.2.0-31.31~22.04.1
> 
> And yes I run my system with:
> 
> linux-image-generic-hwe-22.04                 6.2.0.31.31~22.04.8
> 
> 
> Booted to the 6.2.0-31 kernel version, attempting to do a mount.cifs
> operation to our Samba NT4 PDC, results in the following output into
> syslog:
> 
> Sep  4 08:03:24 jaakob kernel: [  107.703886] FS-Cache: Loaded
> Sep  4 08:03:24 jaakob kernel: [  107.824160] Key type cifs.spnego
> registered Sep  4 08:03:24 jaakob kernel: [  107.824169] Key type
> cifs.idmap registered Sep  4 08:03:24 jaakob kernel: [  107.824454]
> Use of the less secure dialect vers=1.0 is not recommended unless
> required for access to very old servers Sep  4 08:03:24 jaakob
> kernel: [  107.824454] Sep  4 08:03:24 jaakob kernel: [  107.824457]
> CIFS: VFS: Use of the less secure dialect vers=1.0 is not recommended
> unless required for access to very old servers Sep  4 08:03:24 jaakob
> kernel: [  107.824460] CIFS: Attempting to mount \\ldslnx01\data Sep
> 4 08:03:24 jaakob kernel: [  107.859554] CIFS: VFS: cifs_mount failed
> w/return code = -5
> 
> And none of the Samba mounts will establish.
> 
> Booting back to the prior 6.2.0-26 kernel version, Samba mounts work
> just fine.
> 
> I use the following switches to the mount.cifs command in order to
> establish connections to our Samba NT4 PDC:
> 
> "-o
> credentials=/home/mdlueck/.smbcredentials,uid=mdlueck,gid=mdlueck,dir_mode=0777,file_mode=0666,nobrl,vers=1.0"
> 
> 
> That last vers= option was the last that needed to be added to
> continue making use of our Samba NT4 style PDC.
> 
> Since it is a version upgrade of only the kernel, not Samba package,
> I would not think that yet another switch to mount.cifs was needed in
> order to continue connecting successfully. So did the latest Kernel
> update suddenly break Samba's mount.cifs vers=1.0 support?
> 
> Nothing gets logged to our Samba server for the failed mount attempt.
> 
> 
> Dropped back to the just prior kernel version as a successful
> workaround.
> 
> I am thankful,
> 

I don't think this is Samba problem, I think it could be because the
kernel dropped support for NTLMv1.

Rowland