How to make Samba smbfs / cifs mount share location with user / pass credentials authenticate via file stored credentials

how-to-use-username-and-password-to-authenticate-to-samba-share-server-or-linux-share-server-linux-samba-logo
That's pretty trivial and perhaps if you had to manage samba server or cifs on a Linux host you already know it but for beginners, that might be interesting.

So in this short article I will explain how to make configure smbfs / cifs authentication from Linux host A client to Linux host B server running smbd and nmbd samba server (which is the smfs / cifs share server) by using external authentication file for either mount command or if /etc/fstab used to automatically authenticate using a preconfigured mount saba share via /etc/fstab.

Before you start to do anything with samba on Linux host A client machine, you will need as a minimum to have installed cifs-utils or smbfs (assuming you're on Debian Linux like you can check with dpkg -l and if missing install it via:

 

 

apt-get install cifs-utils

 

Or on older systems or for smbfs support

 

apt-get install smbfs

 

The general mount smbfs share command without specified external credentials file would look like so:

 

mount //mynetworksharename/ /shares/data -o username=myusername, password=mypassword


So how to use external auth file to prevent samba shares  users and passwords to not be stored in root user history all the time?

To do so it is pretty straight forward all you need to do is to create a single user / pass credentials variable defined lets say to file called .smbcredentials or .cifs under some directory lets /root/.smbcredentials.

One note here is (many people prefer to store the password under /root) for security reasons as root directory is usually readable only by administrator and would prevent a non-privileged user to read the user / pass which are stored in plain text.

.smbcredentials is described in mount.cifs man page, here is what it says about credentials variable understood by mount / mount.cifs command  file syntax:
 

 

credentials=filename
    specifies a file that contains a username and/or password. The format of the file is:

         username=value
         password=value


For a CIFS (Common Internet File System) which is a new implementation of old Windows Share (SMB protocol) avaiable in newer Windows XP / 7 / 10 machines, to do the cifs mount manually:
 

mount -v -t cifs //WINSHARESERVER/topsecretfiles /mnt/network/ -o credentials=/mnt/creds-file

or use 

 

mount.cifs //WINSSHARE/topsecretfiles /mnt/network/ -o credentials=/root/.creds-file

 

For old smbfs protocol for backward compatibility so older Win 2000 or Winblows server XP PCs configured to also access the Linux samba mount.

mount -t smbfs //WINHARESERVER/topsecretfiles /mnt/network/ -o credentials=/mnt/.smbcredentials


Once you have the defined .smbcredentials file name, be sure to also protect it with properly set permissions like 0600 (rw) readable only for root user. 

chmod 0600 /root/.smbcredentials

Note that in that example .smbcredentials is set to be a hidden file on purpose as this is a hidden file it will make it slightly less seenable if introduder breaks on the server (an example of security through obscurity)

 

Next lets see how to mount the Windows Samba Share permanently with predefined user / pass server login

For many non secured Windows shares one can use /etc/fstab line definition as simple as:
 

//server-share-name/sharename  /mnt/shares/sharename  cifs  guest,uid=1000,iocharset=utf8  0


For password protected Win Share mounts however, the simplest way to do is via /etc/fstab line add like so:

 

 

 

//servername/sharename  /mnt/shares/sharename  cifs  username=msusername,password=mspassword,iocharset=utf8,sec=ntlm  0  0


Note that the sec=ntlm is optional and remote samba server or Windows Share server version has to support this kind of authentication and in some cases you could safely reove sec=ntlm, just use it, when you know what you're doing. iocharset is good to have as for Russian / Bulgarian e.g.  Cyrillic, Chineese, Indian and other exotic languages and other strange language encoding to be supported and properly shown on the mounted share it should be properly defined …, 

A good permissions would be:

chmod 600 ~/.smbcredentials

To use the external /root/.smbcredentials password it shold be like so:

 

 

 

 

 

 

 

# cat /root/.smbcredentials

username=msusername
password=mssecretpassword
56#

 

 

Finally /root/.smbcredentials record should be as so:
 

//share-server-name/sharename /mnt/shares/windowsshare cifs credentials=/home/ubuntuusername/.smbcredentials,iocharset=utf8,sec=ntlm 0 0


Note You should already have

/mnt/shares/windowshare created on server B (the ount client) with:

mkdir -p  /mnt/shares/windowshare


To mount /etc/fstab defined filesystem to mount on next server boot then do

mount /mnt/shares/windowshare


or completely mount / remount all present /etc/fstab filesystems with the common

mount -a


(but here be careful as this might cause you troubles already other NFS or whatever FS is mounted and being read by clients) :

And you the remote Samba Share (mount location) – should be reachable with ping command and traceroute and remote server ports 139, 445 etc. should be up running opened and connectable from server B share-server-name/sharename

If you face some issues when trying to mount remote share with mount -t smbfs / mount.cifs then you can use smbclient with debug option to find out some more on the connectivity / authentication issue by using the smb share server IP address instead of hostnae and lets say a debug level of 3 like so:

 

 

 

 

smbclient -d3 -L //10.5.8.118/Files -A /root/.smbcredentials

[0] smbclient -d3 -L //10.2.3.111/Files -A /home/acteam/.smbcredentials     lp_load_ex: refreshing parameters
Initialising global parameters
rlimit_max: increasing rlimit_max (1024) to minimum Windows limit (16384)
Processing section "[global]"
WARNING: The "syslog" option is deprecated
added interface eth0 ip=10.2.3.127 bcast=10.2.3.255 netmask=255.255.255.0
Client started (version 4.3.11-Ubuntu).
Connecting to 10.2.3.111 at port 445
Doing spnego session setup (blob length=120)
got OID=1.3.6.1.4.1.311.2.2.30
got OID=1.2.840.48018.1.2.2
got OID=1.2.840.113554.1.2.2
got OID=1.2.840.113554.1.2.2.3
got OID=1.3.6.1.4.1.311.2.2.10
got principal=not_defined_in_RFC4178@please_ignore
GENSEC backend 'gssapi_spnego' registered
GENSEC backend 'gssapi_krb5' registered
GENSEC backend 'gssapi_krb5_sasl' registered
GENSEC backend 'spnego' registered
GENSEC backend 'schannel' registered
GENSEC backend 'naclrpc_as_system' registered
GENSEC backend 'sasl-EXTERNAL' registered
GENSEC backend 'ntlmssp' registered
GENSEC backend 'ntlmssp_resume_ccache' registered
GENSEC backend 'http_basic' registered
GENSEC backend 'http_ntlm' registered
GENSEC backend 'krb5' registered
GENSEC backend 'fake_gssapi_krb5' registered
Got challenge flags:
Got NTLMSSP neg_flags=0x62898215
NTLMSSP: Set final flags:
Got NTLMSSP neg_flags=0x62088215
NTLMSSP Sign/Seal – Initialising with flags:
Got NTLMSSP neg_flags=0x62088215
NTLMSSP Sign/Seal – Initialising with flags:
Got NTLMSSP neg_flags=0x62088215
Domain=[TMGRID] OS=[Windows Server 2012 R2 Standard 9600] Server=[Windows Server 2012 R2 Standard 6.3]

 

        Sharename       Type      Comment
        ———       —-      ——-
        ADMIN$          Disk      Remote Admin
        C$              Disk      Default share
        Files           Disk
        IPC$            IPC       Remote IPC
        MappedDrive     Disk
Connecting to 10.2.3.111 at port 139
Connecting to 10.2.3.111 at port 139
Connection to 10.2.3.111 failed (Error NT_STATUS_RESOURCE_NAME_NOT_FOUND)
NetBIOS over TCP disabled — no workgroup available

 

Sum it up

Lets Summarize a bit, here I described how to mount smbfs and cifs mount shares with mount command, how to define the auto mount on server boot via /etc/fstab, how to mount manually /etc/fstab defined mount and what should be the syntax of .smbcredentials user / pass file and also pointed how to debug problems on samba / windows server location share mounts with smbclient command.
 

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3 Responses to “How to make Samba smbfs / cifs mount share location with user / pass credentials authenticate via file stored credentials”

  1. admin says:
    Google Chrome 75.0.3770.142 Google Chrome 75.0.3770.142 Windows 7 x64 Edition Windows 7 x64 Edition
    Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36

    One small hint in case if you have no password protection for a share and want to avoid the annoying pasword samba prompt the way to do it is like so:  
    smbclient -U% //192.168.1.2/My_Folder

    Once connected you can use Linux commands to list and travel between files.

    File transfer with smbclient is also possible by  using get, put, mget, and mput commands.

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  2. admin says:
    Google Chrome 75.0.3770.142 Google Chrome 75.0.3770.142 Windows 7 x64 Edition Windows 7 x64 Edition
    Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36

    ♦ Something else I forgot to mention in article, If it happens that some samba pass credential has been lost it is useful to change samba user password with command:

     smbpasswd smbusername

    ♦ To create a samba entry for an existing system user, use the pdbedit command:

    if it is needded to add a complete new unexisting user to the samba users do:

     smbserver:~# pdbedit -a NewSmbUserName

    By default samba server password database (if not changed to another location in smb.conf is stored on server) under:

    /var/lib/samba/private/passdb.tdb

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  3. admin says:
    Google Chrome 75.0.3770.142 Google Chrome 75.0.3770.142 Windows 7 x64 Edition Windows 7 x64 Edition
    Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36

    ♦ Also, If you need to join a Linux Samba Server to a Windows Domain from the Windows domain using the net command run:

    $ net join -w WINDOWS-DOMAIN -s ' win-server' -U Administrator%password

    ♦ You can then list the users in the Windows domain using wbinfo command

    $ wbinfo -u

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