Invalid response error: invalid negotiate flags

[Yihao-G]

I'm having problems with connecting to the smb server when I run smbDialer.Dial(conn). It reports invalid response error: invalid negotiate flags.

	conn, err := net.Dial("tcp", "123.123.123.123:445")
	if err != nil {
		fmt.Println(err)
		return
	}
	defer conn.Close()

	smbDialer := &smb2.Dialer{
		Initiator: &smb2.NTLMInitiator{
			User:     "myusername",
			Password: "mypassword",
			Domain:   "NTADMIN",
		},
	}
	smbSession, err := smbDialer.Dial(conn)
	if err != nil {
		fmt.Println(err) // error reported here
		return
	}
	defer smbSession.Logoff()

After digging into the source code, I found the error is from this if statement:

go-smb2/internal/ntlm/client.go

Lines 83 to 85 in 6569ee9

	if flags&NTLMSSP_REQUEST_TARGET == 0 {
	return nil, errors.New("invalid negotiate flags")
	}

After commenting out this if statement, I can connect to the smb server and read files no problem.

Looks like this is the part of the NegotiateFlags field. Will it have any security concerns if I comment out this if statement as a quick fix on my side?

Can you please let me know how I can debug this better for you to diagnose the problem? I'm happy to provide more information if needed.

[cocmorph]

Facing the same issue, any update or comments on this?

[ncw]

Users have seen this problem in the SMB backend in rclone.

rclone/rclone#6659

It seems to be maybe problems interacting with embedded SMB agents?