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Old 06-14-2011, 04:33 AM   #1
Larry James
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Location: Buffalo, New York
Distribution: Ubuntu, Raspbian
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How to mount samba home directories as read/write?


I'm trying to configure a per user samba login for full access to the user's home directory.

Mounting the shared directory works flawless when mounting from Windows. I can read, write, create without problems. However, when mounting from Linux the shared space is readonly.

My smb.conf file (Namely the [Homes] area):

Code:
#
# Sample configuration file for the Samba suite for Debian GNU/Linux.
#
#
# 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 most of which 
# are not shown in this example
#
# Some options that are often worth tuning have been included as
# commented-out examples in this file.
#  - When such options are commented with ";", the proposed setting
#    differs from the default Samba behaviour
#  - When commented with "#", the proposed setting is the default
#    behaviour of Samba but the option is considered important
#    enough to be mentioned here
#
# NOTE: Whenever you modify this file you should run the command
# "testparm" to check that you have not made any basic syntactic 
# errors. 
# A well-established practice is to name the original file
# "smb.conf.master" and create the "real" config file with
# testparm -s smb.conf.master >smb.conf
# This minimizes the size of the really used smb.conf file
# which, according to the Samba Team, impacts performance
# However, use this with caution if your smb.conf file contains nested
# "include" statements. See Debian bug #483187 for a case
# where using a master file is not a good idea.
#

#======================= Global Settings =======================

[global]

## Browsing/Identification ###

# Change this to the workgroup/NT-domain name your Samba server will part of
   workgroup = workgroup

# server string is the equivalent of the NT Description field
   server string = %h server (Samba, Ubuntu)

# Windows Internet Name Serving Support Section:
# WINS Support - Tells the NMBD component of Samba to enable its WINS Server
#   wins support = no

# 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

# This will prevent nmbd to search for NetBIOS names through DNS.
   dns proxy = no

# What naming service and in what order should we use to resolve host names
# to IP addresses
;   name resolve order = lmhosts host wins bcast

#### Networking ####

# The specific set of interfaces / networks to bind to
# This can be either the interface name or an IP address/netmask;
# interface names are normally preferred
;   interfaces = 127.0.0.0/8 eth0

# Only bind to the named interfaces and/or networks; you must use the
# 'interfaces' option above to use this.
# It is recommended that you enable this feature if your Samba machine is
# not protected by a firewall or is a firewall itself.  However, this
# option cannot handle dynamic or non-broadcast interfaces correctly.
;   bind interfaces only = yes



#### Debugging/Accounting ####

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

# Cap the size of the individual log files (in KiB).
   max log size = 1000

# If you want Samba to only log through syslog then set the following
# parameter to 'yes'.
#   syslog only = no

# We want Samba to log a minimum amount of information to syslog. Everything
# should go to /var/log/samba/log.{smbd,nmbd} instead. If you want to log
# through syslog you should set the following parameter to something higher.
   syslog = 0

# Do something sensible when Samba crashes: mail the admin a backtrace
   panic action = /usr/share/samba/panic-action %d


####### Authentication #######

# "security = user" is always a good idea. This will require a Unix account
# in this server for every user accessing the server. See
# /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/ServerType.html
# in the samba-doc package for details.
#   security = user

# You may wish to use password encryption.  See the section on
# 'encrypt passwords' in the smb.conf(5) manpage before enabling.
   encrypt passwords = true

# If you are using encrypted passwords, Samba will need to know what
# password database type you are using.  
   passdb backend = tdbsam

   obey pam restrictions = yes

# This boolean parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
   unix password sync = yes

# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<kahan@informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
   passwd program = /usr/bin/passwd %u
   passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .

# This boolean controls whether PAM will be used for password changes
# when requested by an SMB client instead of the program listed in
# 'passwd program'. The default is 'no'.
   pam password change = yes

# This option controls how unsuccessful authentication attempts are mapped
# to anonymous connections
   map to guest = bad user

########## Domains ###########

# Is this machine able to authenticate users. Both PDC and BDC
# must have this setting enabled. If you are the BDC you must
# change the 'domain master' setting to no
#
;   domain logons = yes
#
# The following setting only takes effect if 'domain logons' is set
# It specifies the location of the user's profile directory
# from the client point of view)
# The following required a [profiles] share to be setup on the
# samba server (see below)
;   logon path = \\%N\profiles\%U
# Another common choice is storing the profile in the user's home directory
# (this is Samba's default)
#   logon path = \\%N\%U\profile

# The following setting only takes effect if 'domain logons' is set
# It specifies the location of a user's home directory (from the client
# point of view)
;   logon drive = H:
#   logon home = \\%N\%U

# The following setting only takes effect if 'domain logons' is set
# It specifies the script to run during logon. The script must be stored
# in the [netlogon] share
# NOTE: Must be store in 'DOS' file format convention
;   logon script = logon.cmd

# This allows Unix users to be created on the domain controller via the SAMR
# RPC pipe.  The example command creates a user account with a disabled Unix
# password; please adapt to your needs
; add user script = /usr/sbin/adduser --quiet --disabled-password --gecos "" %u

# This allows machine accounts to be created on the domain controller via the 
# SAMR RPC pipe.  
# The following assumes a "machines" group exists on the system
; add machine script  = /usr/sbin/useradd -g machines -c "%u machine account" -d /var/lib/samba -s /bin/false %u

# This allows Unix groups to be created on the domain controller via the SAMR
# RPC pipe.  
; add group script = /usr/sbin/addgroup --force-badname %g

########## Printing ##########

# If you want to automatically load your printer list rather
# than setting them up individually then you'll need this
#   load printers = yes

# lpr(ng) printing. You may wish to override the location of the
# printcap file
;   printing = bsd
;   printcap name = /etc/printcap

# CUPS printing.  See also the cupsaddsmb(8) manpage in the
# cupsys-client package.
;   printing = cups
;   printcap name = cups

############ Misc ############

# 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 = /home/samba/etc/smb.conf.%m

# Most people will find that this option gives better performance.
# See smb.conf(5) and /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/speed.html
# for details
# You may want to add the following on a Linux system:
#         SO_RCVBUF=8192 SO_SNDBUF=8192
#   socket options = TCP_NODELAY

# The following parameter is useful only if you have the linpopup package
# installed. The samba maintainer and the linpopup maintainer are
# working to ease installation and configuration of linpopup and samba.
;   message command = /bin/sh -c '/usr/bin/linpopup "%f" "%m" %s; rm %s' &

# Domain Master specifies Samba to be the Domain Master Browser. If this
# machine will be configured as a BDC (a secondary logon server), you
# must set this to 'no'; otherwise, the default behavior is recommended.
#   domain master = auto

# Some defaults for winbind (make sure you're not using the ranges
# for something else.)
;   idmap uid = 10000-20000
;   idmap gid = 10000-20000
;   template shell = /bin/bash

# The following was the default behaviour in sarge,
# but samba upstream reverted the default because it might induce
# performance issues in large organizations.
# See Debian bug #368251 for some of the consequences of *not*
# having this setting and smb.conf(5) for details.
;   winbind enum groups = yes
;   winbind enum users = yes

# Setup usershare options to enable non-root users to share folders
# with the net usershare command.

# Maximum number of usershare. 0 (default) means that usershare is disabled.
;   usershare max shares = 100

# Allow users who've been granted usershare privileges to create
# public shares, not just authenticated ones
   usershare allow guests = yes

#======================= Share Definitions =======================

# Un-comment the following (and tweak the other settings below to suit)
# to enable the default home directory shares. This will share each 
# user's home director as \\server\username
[homes]
   comment = Home Directories
   browseable = no
   writeable = yes

# By default, the home directories are exported read-only. Change the
# next parameter to 'no' if you want to be able to write to them.
   read only = no

# File creation mask is set to 0700 for security reasons. If you want to
# create files with group=rw permissions, set next parameter to 0775.
;   create mask = 0700

# Directory creation mask is set to 0700 for security reasons. If you want to
# create dirs. with group=rw permissions, set next parameter to 0775.
;   directory mask = 0700

# By default, \\server\username shares can be connected to by anyone
# with access to the samba server. Un-comment the following parameter
# to make sure that only "username" can connect to \\server\username
# The following parameter makes sure that only "username" can connect
#
# This might need tweaking when using external authentication schemes
   valid users = %S

# Un-comment the following and create the netlogon directory for Domain Logons
# (you need to configure Samba to act as a domain controller too.)
;[netlogon]
;   comment = Network Logon Service
;   path = /home/samba/netlogon
;   guest ok = yes
;   read only = yes

# Un-comment the following and create the profiles directory to store
# users profiles (see the "logon path" option above)
# (you need to configure Samba to act as a domain controller too.)
# The path below should be writable by all users so that their
# profile directory may be created the first time they log on
;[profiles]
;   comment = Users profiles
;   path = /home/samba/profiles
;   guest ok = no
;   browseable = no
;   create mask = 0600
;   directory mask = 0700

[printers]
   comment = All Printers
   browseable = no
   path = /var/spool/samba
   printable = yes
   guest ok = no
   read only = yes
   create mask = 0700

# Windows clients look for this share name as a source of downloadable
# printer drivers
[print$]
   comment = Printer Drivers
   path = /var/lib/samba/printers
   browseable = yes
   read only = yes
   guest ok = no
# Uncomment to allow remote administration of Windows print drivers.
# You may need to replace 'lpadmin' with the name of the group your
# admin users are members of.
# Please note that you also need to set appropriate Unix permissions
# to the drivers directory for these users to have write rights in it
;   write list = root, @lpadmin

# A sample share for sharing your CD-ROM with others.
;[cdrom]
;   comment = Samba server's CD-ROM
;   read only = yes
;   locking = no
;   path = /cdrom
;   guest ok = yes

# The next two parameters show how to auto-mount a CD-ROM when the
#	cdrom share is accesed. For this to work /etc/fstab must contain
#	an entry like this:
#
#       /dev/scd0   /cdrom  iso9660 defaults,noauto,ro,user   0 0
#
# The CD-ROM gets unmounted automatically after the connection to the
#
# If you don't want to use auto-mounting/unmounting make sure the CD
#	is mounted on /cdrom
#
;   preexec = /bin/mount /cdrom
;   postexec = /bin/umount /cdrom

[olympia]
	comment = Office Shared
	path = /pshared/olympia
	writeable = yes
;	browseable = yes
	valid users = apollo, ljames
The command to mount the drive:
Code:
$ sudo mount -o username=ljames //hera5/ljames myhera5
When trying to create a file I get “Permission Denied”.

The [Olympia] share works (mounts read/write) okay from both Windows and Linux.

-- L. James

--
L. D. James
ljames@apollo3.com
www.apollo3.com/~ljames
 
Old 06-14-2011, 05:20 AM   #2
ambrop7
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Try mounting with something like this:

Code:
mount -t cifs -o username=ljames,nounix,uid=1000,gid=100,dir_mode=0770,file_mode=0660 //hera5/ljames myhera5
This will make the mounted files have uid=1000, gid=100, and be read-write for those two.
 
1 members found this post helpful.
Old 06-14-2011, 09:28 AM   #3
Larry James
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Registered: Jun 2000
Location: Buffalo, New York
Distribution: Ubuntu, Raspbian
Posts: 381

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Rep: Reputation: 40
Quote:
Originally Posted by ambrop7 View Post
Try mounting with something like this:

Code:
mount -t cifs -o username=ljames,nounix,uid=1000,gid=100,dir_mode=0770,file_mode=0660 //hera5/ljames myhera5
This will make the mounted files have uid=1000, gid=100, and be read-write for those two.
Thanks, Ambrop. I tried the commandline. The "nounix" option will cause a syntax failure. Removing the "nounix" option and the results is the same as my original command.

By the way, just wondering, where did you get the uid (1000) and the gid (100) from? And if it had worked would the files created from the linux client have the proper uid of the files on the server (in the users home directory)?

Files created from the Windows client are created with the proper uid of the host.

-- L. James

--
L. D. James
ljames@apollo3.com
www.apollo3.com/~ljames

-- L. James

--
L. D. James
ljames@apollo3.com
www.apollo3.com/~ljames
 
Old 06-14-2011, 09:58 AM   #4
ambrop7
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By default, the CIFS mounts will make use of CIFS Unix Extensions if supported by the server. This means that if you run Samba and mount the drive from Linux, the mounted files will have the same attributes (uid, gid, permissions) as on the Samba server. This however only makes sense if your UIDs and GIDs are synchronized between the server and the client. On the client, the permissions of the mounted files will locally correspond to whatever users the uid/gid from the server map to.

For example: on the server you have:
userA UID=1000
userB UID=1001

And on the client you have:
user1 UID=1000

Now if you mount the home folder of userB from the client, the local UID of the mounted files will be 1001, which, on the client machine, represents no user. This means, if you attempt write the mounted files as user1, since the UIDs differ, the 'other' (or maybe 'group') permissions bits will be used, which may not include write permissions - hence, write will be denied locally, as part of the usual permission checks.

The solution is to locally override the UIDs and GIDs of the mounted files. So, if 'user1' on the client needs exclusive access to the files, you add the mount option uid=1000. This will make the mounted files appear to have UID=1000 - the UID of user1, allowing user1 access to whatever the 'user' bits of the permissions say.

You can give access to a whole group using the gid= mount option (GID=100 usually corresponds to the 'users' group). This will give that group permissions to whatever the 'group' permisisons of the file say.

However, by default the permission bits will be the same as on the server. So if you want to add the 'users' group access to mounted files, some files may not have the required group permissions on the server. So you locally override those with the dir_mode= and file_mode= options.

Be aware that any attributes you locally override ad mount time (uid, gid, permissions) will have no effect on the file attributes on the server. When you create new files through the mounted filesystem, these local permissions will also have no effect in the selection of server-side file attributes.

Finally, the 'nounix' option is needed to force these options to have any effect at all, since, if CIFS Unix Extensions are present, the server attributes will still be used. You appear to have an old mount.cifs program (or an old kernel?) which doesn't support the 'nounix' options. Your Windows mount is probably working fine because Windows doesn't have CIFS Unix Extensions, and the kernel uses some default permissions which happen to allow write access.

Last edited by ambrop7; 06-14-2011 at 10:00 AM.
 
Old 06-14-2011, 10:25 AM   #5
Larry James
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Quote:
Originally Posted by ambrop7 View Post
Finally, the 'nounix' option is needed to force these options to have any effect at all, since, if CIFS Unix Extensions are present, the server attributes will still be used. You appear to have an old mount.cifs program (or an old kernel?) which doesn't support the 'nounix' options. Your Windows mount is probably working fine because Windows doesn't have CIFS Unix Extensions, and the kernel uses some default permissions which happen to allow write access.
Thanks. The client machine is Ubuntu 11.04 using only samba and cifs utilities installed via apt-get or synaptic from the Natty repositories. I understand even though the Natty installation is brand new some of the files in the repository might still be old.

The host machine is less than a year old. It was build from a fresh install of Ubuntu 10.10 and upgraded to 11.04. All the components of that installation are from the official repositories also.

There's a chance that there might be another component of the client (or the server) that might be missing in order to support the nounix option.

Do you know of a way to verify the installation of the proper nounix supported mount.cifs components?

-- L. James

--
L. D. James
ljames@apollo3.com
www.apollo3.com/~ljames
 
Old 06-14-2011, 11:06 AM   #6
ambrop7
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I have installed the cifs-utils packages on a brand new Ubuntu 11.04 install, and the 'nounix' option does work. It is also documented in the mount.cifs man page. What exactly is your mount command, and what errors are you getting (dmesg also maybe)?

EDIT: you can also disable the CIFS Unix Extensions on the server (for all shares only):

[global]
unix extensions = no

Last edited by ambrop7; 06-14-2011 at 11:07 AM.
 
Old 06-14-2011, 11:08 AM   #7
Larry James
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Registered: Jun 2000
Location: Buffalo, New York
Distribution: Ubuntu, Raspbian
Posts: 381

Original Poster
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Quote:
Originally Posted by ambrop7 View Post
Try mounting with something like this:

Code:
mount -t cifs -o username=ljames,nounix,uid=1000,gid=100,dir_mode=0770,file_mode=0660 //hera5/ljames myhera5
This will make the mounted files have uid=1000, gid=100, and be read-write for those two.
I don't know what was happening before, but the command including the nounix option is going through without errors at this time. I did a complete copy and paste. It returned without an error. However, when I get a "Permission denied" error when trying to access the directory.

If I change the uid option from 1000 to 1001 (which is my userid on the client machine) I can access the directory but it's empty.

I'm still trying other variations.

By the way, I thought I had performed a copy and paste before when I was getting syntax errors.

-- L. James

--
L. D. James
ljames@apollo3.com
www.apollo3.com/~ljames
 
Old 06-14-2011, 11:14 AM   #8
ambrop7
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Quote:
Originally Posted by Larry James View Post
If I change the uid option from 1000 to 1001 (which is my userid on the client machine) I can access the directory but it's empty.
List the directory itself and the contents as root to make sure the permissions are right:

Code:
$ su
$ ls -ld myhera5
$ ls -l myhera5
The uid/gid/permissions should match the mount options in the mount command.
 
Old 06-14-2011, 11:23 AM   #9
Larry James
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Registered: Jun 2000
Location: Buffalo, New York
Distribution: Ubuntu, Raspbian
Posts: 381

Original Poster
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Quote:
Originally Posted by ambrop7 View Post
List the directory itself and the contents as root to make sure the permissions are right:

Code:
$ su
$ ls -ld myhera5
$ ls -l myhera5
The uid/gid/permissions should match the mount options in the mount command.
I dropped the "nounix", made the uid (1001) my userid and it works perfectly just like windows.

By the way, the sudo shows and empty directory when the "nounix" option is used.

Thanks for helping me to gain this access. The purpose was to edit files in one of my remote machines on a local machine, and to allow other users to do the same in their own personal directories.

If you want, I can continue to experiment to try to figure out why the "nounix" option breaks things.

-- L. James

--
L. D. James
ljames@apollo3.com
www.apollo3.com/~ljames
 
  


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