[Solved] Samba: Permissions and shared status do not work.

Soukyuu · 2014-04-16 00:48:21

I recently set up a test VM to prepare to move my home server to linux.
After following the steps detailed here, it doesn't work as expected.

There is no "sharing" section in my KDE system settings as described in the wiki. I was able to get the properties pane working, but only partially.
I can share a folder and accessing it works. The problem is that the permissions do not seem to update.
If I have set the initial permissions to allow userone to only read the contents, I cannot seem to give userone write permissions afterwards. The property pane shows full access permission is set, but I still get "no permission" error on my windows machine.
Worse yet, it doesn't seem to update the sharing status either - if I unshare a folder, I have to do it twice for the shared icon to disappear in dolphin. And even after that, the share appears visible from a windows machine.
The most confusing is that stopping/restarting smbd and nmbd does not update the share status either, nor does rebooting the VM.

I'm quite new to linux so I'm not sure where to start poking to debug this. I also see a lot of different problems related to samba, but the only closest one to mine was this thread. There is a post saying it was solved by an entry in the wiki, but that entry no longer exists. I'd really want to get this working reliably, so please tell me which info I should provide.

Last edited by Soukyuu (2014-04-23 14:46:10)

Soukyuu · 2014-04-21 17:11:13

I must say this is getting ridiculous. Here is my samba user list:

$ sudo pdbedit -L
usera:1000:
userb:1001:

Using the samba documentation, I create a new share:

$ net usershare add test /home/usera/test/ "" usera:f,userb:r guest_ok=n

Result: usera can log in, userb can NOT?!

Ok, maybe I messed up on the syntax. Let's try something else:

$ net usershare add test /home/usera/test/ "" userb:f guest_ok=n

Result: usera cannot log in as expected. userb can STILL not log in.

smb.conf

# This is the main Samba configuration file. You should read the
# smb.conf(5) manual page in order to understand the options listed
# here. Samba has a huge number of configurable options (perhaps too
# many!) most of which are not shown in this example
#
# Any line which starts with a ; (semi-colon) or a # (hash) 
# is a comment and is ignored. In this example we will use a #
# for commentry and a ; for parts of the config file that you
# may wish to enable
#
# NOTE: Whenever you modify this file you should run the command "testparm"
# to check that you have not made any basic syntactic errors. 
#
#======================= Global Settings =====================================
[global]
usershare path = /var/lib/samba/usershare
usershare max shares = 100
usershare allow guests = no
usershare owner only = no

# workgroup = NT-Domain-Name or Workgroup-Name
   workgroup = WORKGROUP

# server string is the equivalent of the NT Description field
   server string = Samba Server

# This option is important for security. It allows you to restrict
# connections to machines which are on your local network. The
# following example restricts access to two C class networks and
# the "loopback" interface. For more examples of the syntax see
# the smb.conf man page
;   hosts allow = 192.168.1. 192.168.2. 127.
hosts allow = 192.168.178. 127.

# if you want to automatically load your printer list rather
# than setting them up individually then you'll need this
;   printcap name = /etc/printcap
   printcap name = /dev/null
   load printers = no
   disable spoolss = yes

# It should not be necessary to spell out the print system type unless
# yours is non-standard. Currently supported print systems include:
# bsd, sysv, plp, lprng, aix, hpux, qnx
;   printing = bsd

# Uncomment this if you want a guest account, you must add this to /etc/passwd
# otherwise the user "nobody" is used
;  guest account = pcguest

# this tells Samba to use a separate log file for each machine
# that connects
   log file = /var/log/samba/%m.log

# Put a capping on the size of the log files (in Kb).
   max log size = 50

# Security mode. Most people will want user level security. See
# security_level.txt for details.
   security = user
# Use password server option only with security = server
;   password server = <NT-Server-Name>

# Password Level allows matching of _n_ characters of the password for
# all combinations of upper and lower case.
;  username level = 8

# You may wish to use password encryption. Please read
# ENCRYPTION.txt, Win95.txt and WinNT.txt in the Samba documentation.
# Do not enable this option unless you have read those documents
;  encrypt passwords = yes
;  smb passwd file = /etc/samba/smbpasswd

# The following are needed to allow password changing from Windows to
# update the Linux sytsem password also.
# NOTE: Use these with 'encrypt passwords' and 'smb passwd file' above.
# NOTE2: You do NOT need these to allow workstations to change only
#        the encrypted SMB passwords. They allow the Unix password
#        to be kept in sync with the SMB password.
;  unix password sync = Yes
;  passwd program = /usr/bin/passwd %u
;  passwd chat = *New*UNIX*password* %n\n *ReType*new*UNIX*password* %n\n *passwd:*all*authentication*tokens*updated*successfully*

# Unix users can map to different SMB User names
;  username map = /etc/samba/smbusers

# Using the following line enables you to customise your configuration
# on a per machine basis. The %m gets replaced with the netbios name
# of the machine that is connecting
;   include = /etc/samba/smb.conf.%m

# Configure Samba to use multiple interfaces
# If you have multiple network interfaces then you must list them
# here. See the man page for details.
;   interfaces = 192.168.12.2/24 192.168.13.2/24 

# Configure remote browse list synchronisation here
#  request announcement to, or browse list sync from:
#	a specific host or from / to a whole subnet (see below)
;   remote browse sync = 192.168.3.25 192.168.5.255
# Cause this host to announce itself to local subnets here
;   remote announce = 192.168.1.255 192.168.2.44

# Browser Control Options:
# set local master to no if you don't want Samba to become a master
# browser on your network. Otherwise the normal election rules apply
;   local master = no

# OS Level determines the precedence of this server in master browser
# elections. The default value should be reasonable
;   os level = 33

# Domain Master specifies Samba to be the Domain Master Browser. This
# allows Samba to collate browse lists between subnets. Don't use this
# if you already have a Windows NT domain controller doing this job
;   domain master = yes 

# Preferred Master causes Samba to force a local browser election on startup
# and gives it a slightly higher chance of winning the election
;   preferred master = yes

# Use only if you have an NT server on your network that has been
# configured at install time to be a primary domain controller.
;   domain controller = <NT-Domain-Controller-SMBName>

# Enable this if you want Samba to be a domain logon server for 
# Windows95 workstations. 
;   domain logons = yes

# if you enable domain logons then you may want a per-machine or
# per user logon script
# run a specific logon batch file per workstation (machine)
;   logon script = %m.bat
# run a specific logon batch file per username
;   logon script = %U.bat

# Where to store roving profiles (only for Win95 and WinNT)
#        %L substitutes for this servers netbios name, %U is username
#        You must uncomment the [Profiles] share below
;   logon path = \\%L\Profiles\%U

# All NetBIOS names must be resolved to IP Addresses
# 'Name Resolve Order' allows the named resolution mechanism to be specified
# the default order is "host lmhosts wins bcast". "host" means use the unix
# system gethostbyname() function call that will use either /etc/hosts OR
# DNS or NIS depending on the settings of /etc/host.config, /etc/nsswitch.conf
# and the /etc/resolv.conf file. "host" therefore is system configuration
# dependant. This parameter is most often of use to prevent DNS lookups
# in order to resolve NetBIOS names to IP Addresses. Use with care!
# The example below excludes use of name resolution for machines that are NOT
# on the local network segment
# - OR - are not deliberately to be known via lmhosts or via WINS.
; name resolve order = wins lmhosts bcast

# Windows Internet Name Serving Support Section:
# WINS Support - Tells the NMBD component of Samba to enable it's WINS Server
;   wins support = yes

# WINS Server - Tells the NMBD components of Samba to be a WINS Client
#	Note: Samba can be either a WINS Server, or a WINS Client, but NOT both
;   wins server = w.x.y.z

# WINS Proxy - Tells Samba to answer name resolution queries on
# behalf of a non WINS capable client, for this to work there must be
# at least one	WINS Server on the network. The default is NO.
;   wins proxy = yes

# DNS Proxy - tells Samba whether or not to try to resolve NetBIOS names
# via DNS nslookups. The built-in default for versions 1.9.17 is yes,
# this has been changed in version 1.9.18 to no.
   dns proxy = no 

# Case Preservation can be handy - system default is _no_
# NOTE: These can be set on a per share basis
;  preserve case = no
;  short preserve case = no
# Default case is normally upper case for all DOS files
;  default case = lower
# Be very careful with case sensitivity - it can break things!
;  case sensitive = no

#============================ Share Definitions ==============================
#[homes]
#   comment = Home Directories
#   browseable = no
#   writable = yes

# Un-comment the following and create the netlogon directory for Domain Logons
; [netlogon]
;   comment = Network Logon Service
;   path = /home/netlogon
;   guest ok = yes
;   writable = no
;   share modes = no


# Un-comment the following to provide a specific roving profile share
# the default is to use the user's home directory
;[Profiles]
;    path = /home/profiles
;    browseable = no
;    guest ok = yes


# NOTE: If you have a BSD-style print system there is no need to 
# specifically define each individual printer
#[printers]
#   comment = All Printers
#   path = /var/spool/samba
#   browseable = no
# Set public = yes to allow user 'guest account' to print
#   guest ok = no
#   writable = no
#   printable = yes

# This one is useful for people to share files
;[tmp]
;   comment = Temporary file space
;   path = /tmp
;   read only = no
;   public = yes

# A publicly accessible directory, but read only, except for people in
# the "staff" group
;[public]
;   comment = Public Stuff
;   path = /home/samba
;   public = yes
;   read only = yes
;   write list = @staff

# Other examples. 
#
# A private printer, usable only by fred. Spool data will be placed in fred's
# home directory. Note that fred must have write access to the spool directory,
# wherever it is.
;[fredsprn]
;   comment = Fred's Printer
;   valid users = fred
;   path = /homes/fred
;   printer = freds_printer
;   public = no
;   writable = no
;   printable = yes

# A private directory, usable only by fred. Note that fred requires write
# access to the directory.
;[fredsdir]
;   comment = Fred's Service
;   path = /usr/somewhere/private
;   valid users = fred
;   public = no
;   writable = yes
;   printable = no

# a service which has a different directory for each machine that connects
# this allows you to tailor configurations to incoming machines. You could
# also use the %u option to tailor it by user name.
# The %m gets replaced with the machine name that is connecting.
;[pchome]
;  comment = PC Directories
;  path = /usr/pc/%m
;  public = no
;  writable = yes

# A publicly accessible directory, read/write to all users. Note that all files
# created in the directory by users will be owned by the default user, so
# any user with access can delete any other user's files. Obviously this
# directory must be writable by the default user. Another user could of course
# be specified, in which case all files would be owned by that user instead.
;[public]
;   path = /usr/somewhere/else/public
;   public = yes
;   only guest = yes
;   writable = yes
;   printable = no

# The following two entries demonstrate how to share a directory so that two
# users can place files there that will be owned by the specific users. In this
# setup, the directory should be writable by both users and should have the
# sticky bit set on it to prevent abuse. Obviously this could be extended to
# as many users as required.
;[myshare]
;   comment = Mary's and Fred's stuff
;   path = /usr/somewhere/shared
;   valid users = mary fred
;   public = no
;   writable = yes
;   printable = no
;   create mask = 0765

Journal has a lot of

smbd[2860]: [2014/04/21 19:11:46.108064,  0] ../lib/util/pidfile.c:153(pidfile_unlink)
smbd[2860]: Failed to delete pidfile /var/run/smbd.pid. Error was No such file or directory

Messages, according to this it shouldn't affect daemon work.

I am either too stupid to get this, or samba is horribly broken. Yes, I'm entering the correct password.

edit: and yes, the files created by "net usershare add" do contain the correct acls.

edit2: those "Failed to delete pidfile" messages appear the moment I press enter on the authentication dialog, so it fails to switch user, it seems.

edit3: I have just tried the same steps on linux mint 16 (smb ver 3.6.18). Everything works as expected =/
Switching from .socket to .service and rebooting, the "failed to delete pidfile" errors are gone. But now it's showing something ridiculous:

Apr 21 19:55:03 ZacateVM smbd[646]: [2014/04/21 19:55:03.304107,  0] ../source3/smbd/uid.c:153(check_user_share_access)
Apr 21 19:55:03 ZacateVM smbd[646]: user usera connection to test denied due to share security descriptor.

I am logging in as userb, not usera. The message appears several times. First when I get presented with the auth dialog, which is expected. And last, when I enter userb creds and press enter.

Last edited by Soukyuu (2014-04-21 17:58:16)

Soukyuu · 2014-04-23 14:45:40

I managed to solve it.
The problem is the complete unintuitiveness of the linux permission system in addition to the dual permission of the samba layer depending on samba version and/or distribution. Confused yet? I am.

Following situation:
/home/usera/ permissions on arch (default): -rwx------
/home/usera/ permissions on mint (default): -rwxr--r--

I was sharing the folder
/home/usera/test: -rwxrwxrwx

On mint, everyone was able to read all folders of the path, so userb was able to access the shared folder.
On arch I am getting access denied because (my guess):
- userb authenticates with samba - OK
- userb tries to access the folder, but only usera is allowed to look into /home/usera - FAIL
- samba then switches to usera, but usera is not allowed to browse the share - FAIL

Creating a "shares" directory in /, setting permissions to 777 and then creating the shares there works. I still have to set the permissions per share in linux AND in samba though.
Why so complicated? Can't samba adjust the permissions according to share rules automatically? I assumed "usershare owner only" would also take care of that, else it's an "I am allowed to share the folder, but not use it". Very intuitive.
And if it's a filesystem permission issue, why are there no error messages in the logs? *sigh*

Arch Linux

#1 2014-04-16 00:48:21

[Solved] Samba: Permissions and shared status do not work.

#2 2014-04-21 17:11:13

Re: [Solved] Samba: Permissions and shared status do not work.

#3 2014-04-23 14:45:40

Re: [Solved] Samba: Permissions and shared status do not work.

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