KeyError: 1 when trying to connect to share hosted by ksmbd

[erlingen]

Hi,

I'm running into issues when using v1.1.0 or later of smbprotocol towards a SMB server that is using ksmbd. The issue seems to be that ksmbd is using session id "1" for the first session which will cause conflicts in the preauth_session_table of the Connection class since items are inserted both by session id (1) and message id (1 for the first session setup request).

I'm using the file-management.py example and get the follwing error:

Traceback (most recent call last): File "/home/erik/smbprotocol/examples/low-level/file-management.py", line 47, in session.connect()
File "/home/erik/.local/lib/python3.9/site-packages/smbprotocol/session.py", line 299, in connect
request = self.connection.send(session_setup, sid=self.session_id, credit_request=64) File "/home/erik/.local/lib/python3.9/site-packages/smbprotocol/connection.py", line 965, in send return self._send( File "/home/erik/.local/lib/python3.9/site-packages/smbprotocol/connection.py", line 1281, in _send self.preauth_session_table[session_id].preauth_integrity_hash_value.append(b_header) KeyError: 1

[jborean93]

Do you have an easy way to setup a server that runs ksmbd, I'm having trouble seeing examples online to try and reproduce this. I'll continue trying but if you can help with that it would be great.

[erlingen]

I'll try to find a way to build a kernel that could be run with qemu for testing this.

[jborean93]

How are you currently running it?

[adiroiban]

I have a standard Ubuntu 22.04 and I can see the ksmbd is available and there is ksmbd-tools - cifsd kernel server userspace utilities

$ sudo modprobe ksmb

---

so I guess that this is a question of providing guidance for generic configuration and steps to reproduce it.

[jborean93]

Yea I'm happy to run a VM of Ubuntu 22.04, it's just the configuration/setting up that is a bit unclear for me. I mostly only tried Fedora/Rocky Linux earlier and found it hard to get ksmbd-tools running.

[erlingen]

Hi again, sorry for the late reply. We use ksmbd to host smb shares on a NAS product at work.

I managed to reproduce it using ubuntu 22.04 in virtualbox as well. Here are some instructions for setting up the share using ksmbd-tools (I used the version 3.4.4-1 available to install with apt):

// Add local user sudo adduser --no-create-home smbuser

// Add the following to configure share in /etc/ksmbd/smb.conf [share] path = /share_test/ read only = no valid user = smbuser guest ok = no

// Create share folder and let smbuser own it sudo mkdir /share_test/ sudo chown -R smbuser /share_test/

// Add user to ksmbd user database sudo ksmbd.adduser -a smbuser

// Load kernel module sudo modprobe ksmbd

// Start ksmbd sudo ksmbd.mountd

I tried both with the ksmbd module available in ubuntu and by building the latest version from github.I had to disable encryption when the Session is created in the file-management.py example by adding False as the fourth argument to Session().

I can get past the KeyError failure by changing the code to use a separate list to insert by message_id here and then look up the value in the new list here

These changes fixes my problems when I'm using it with our NAS but I run into more problems in Ubuntu.

[jborean93]

Thank you very much for sharing that info as well as sharing a way to fix it. The PR https://github.com/jborean93/smbprotocol/pull/224 works for me locally with a ksmbd server. If you have time it wuold be great if you could test it out and confirm it works for your NAS.

[erlingen]

Tested PR 224 and it works towards our NAS as well! Thanks!