Access denied to Samba share after update

Question

As of this morning, I can't reach the Samba share on my server. Both from my Windows PC and from my Ubuntu laptop I get an "access denied" message. This share has been working for years without a single modification in the smb.conf file.

I notice that the Samba package has been auto-updated this morning (I use unattended updates on the server). Is anyone else having this problem, or something similar? The current version is 4.1.6+dfsg-1ubuntu2.14.04.11.

These are the relevant lines from smb.conf (yes it is outdated and pretty insecure for production purposes, but the network is well secured from the outside, and I trust my users). I doublechecked but the file is identical to the one in the backup:

[global]
   workgroup = NLDOM
   server string = %h server (Samba, Ubuntu)
   dns proxy = no
   log file = /var/log/samba/log.%m
   log level = 3
   max log size = 1000
   syslog = 0
   panic action = /usr/share/samba/panic-action %d
  security = SHARE
  client lanman auth = yes
   passdb backend = tdbsam
   obey pam restrictions = yes
   guest account = root
   passwd program = /usr/bin/passwd %u
   passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
   map to guest = bad user
   load printers = yes
   printing = bsd
   printcap name = /etc/printcap
   socket options = TCP_NODELAY
   usershare allow guests = yes
[printers]
   comment = All Printers
   browseable = no
   path = /var/spool/samba
   printable = yes
   guest ok = no
   read only = yes
   create mask = 0700
[print$]
   comment = Printer Drivers
   path = /var/lib/samba/printers
   browseable = yes
   read only = yes
   guest ok = no
[Hallway]
    path = /
    read only=No
    guest only =Yes
    guest ok = Yes
    available = yes
    browsable = yes
    public = yes
    writable = yes 

Note: The mount command succeeds with no problems (nothing in dmesg), but subsequently opening the share in Nautilus, through the cd command, or in an smbclient session, always fails (NT_STATUS_ACCESS_DENIED).

Answer 1

I found this issue after updating Samba this morning, and I found an answer that worked here:

http://ubuntuforums.org/showthread.php?t=1600541&p=9995179#post9995179

Samba has changed the ability to follow symlinks because of a security issue:

http://www.samba.org/samba/news/symlink_attack.html

To circumvent the change you could try this:

Add the following lines to the [global] section of smb.conf:

follow symlinks = yes  
wide links = yes  
unix extensions = no  

Then restart the samba service:

sudo service smbd restart

Answer 2

A similar thing happened to me after an update this morning : smbd version 4.1.6-Ubuntu

I can see the files and folders in the root directory but I can't traverse folders or even edit a file I own in the root directory.

Error is: Acces Denied

For now I have made new shares to my most frequently used subfolders and everything works fine regardless of owner/permission/location

Looks like this only affects the root

smb.conf was not changed and always used to work:

[c$]
   path = /
   valid users = matthew
   read only = no
   guest ok = no
   browseable = yes