Failed to mount Windows share: Software caused connection abort

[Tony Pursell]

Since upgrading from 19.10 to 20.04 I cannot access folders on my NAS.

What happens:

In Nautilus (1:3.36.2-0ubuntu1) I do the following

1. Go to Other Locations
2. Click on Windows Network
3. Double Click on WORKGROUP
4. Double Click on DYLAN (the NAS at 192.168.1.5)
5. Double Click on public (a folder that does not require a password)

I get the error message 'Unable to access location. Failed to mount windows share: Software caused connection abort'.

What should happen:

Following the above steps the public folder opens and shows the files and folders in it.

My backups using Deja Dup also get this error.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: nautilus 1:3.36.2-0ubuntu1
ProcVersionSignature: Ubuntu 5.4.0-31.35-generic 5.4.34
Uname: Linux 5.4.0-31-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Sat May 23 14:13:33 2020
InstallationDate: Installed on 2015-06-21 (1797 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
SourcePackage: nautilus
UpgradeStatus: Upgraded to focal on 2020-05-15 (7 days ago)
usr_lib_nautilus:

[Tony Pursell (ajpursell)]

Have created a workaround which works:

1. created directory ~/.smb
2. copied /etc/samba/smb.conf to it
3. added 'client min protocol = NT1' to [global] section.

as suggested in bug #1879776

[Robie Basak (racb)]

Thank you for taking the time to report this bug and helping to make Ubuntu better.

I believe that there are no plans to allow NT1 by default for security reasons, so I'm marking this as Won't Fix. The workaround is to manually allow it as you found.

[Tony Pursell (ajpursell)]

Hi Robie

I think you've missed the point. There is a bug that was introduced by the upgrade from 19.10 to 20.04. I assume it is somewhere in Samba.

My use of NT1 is not meant to be a fix for the reason you have given. It is just a workaround.

Please change it back from Won't Fix to something suitable and then look for the bug so a secure fix can be implemented. I will then remove my workaround.

Thanks

[Jim Hunziker (landtuna)]

Another workaround (if you're having this problem on a Synology DiskStation, like me) is to pick a higher maximum protocol under the file services advanced settings for SMB on your NAS.

[Tony Pursell (ajpursell)]

Thanks for your comment Jim. My NAS is a ZyXEL NSA325 v2 and doesn't have any access to SMB settings.

[Andreas Hasenack (ahasenack)]

Then you need to downgrade the client side of the connection to SMB1, via 'client min protocol = NT1' in smb.conf on the client.

[Tony Pursell (ajpursell)]

I have done that but I shouldn't have had to. There must have been some change to Samba on the upgrade to 20.04 that caused it.

[Dan Streetman (ddstreet)]

fyi, this was an intentional upstream change, thanks @vtapia for pointing me to the upstream wiki:

https://wiki.samba.org/index.php/Samba_4.11_Features_added/changed#SMB1_is_disabled_by_default

[Sebastian Unger (sebunger44)]

I tried to apply the work-around given here (min client protocol), but am having trouble. It works if I put it into ~/.smb/smb.conf or /etc/samba/smb.conf. However, for various reasons neither file is really appropriate in my case. Instead, I would like to add it to a file that is included from /etc/samba/smb.conf. My /etc/samba/smb.conf looks like this:

include = /usr/share/samba/smb.conf
include = /usr/share/tait-config/ttde-smb.conf
include = /etc/samba/user.conf

If I include the work-around in the [global] section in /usr/share/tait-config/ttde-smb.conf, it is being ignored.

[Sebastian Unger (sebunger44)]

I should clarify that it works when I put it in the [global] section in /usr/share/samba/smb.conf

[masterweaver (masterweaver)]

Tony Pursell, your workaround works for me..