Para adicionar usuarios no SAMBA.
1) Adiciona-o ao Linux.
2) Adiciona-o ao SAMBA atraves do comando smbpasswd -a <nome do usuario>
3) Mexe no arquivo de configuração smb.conf para dar privilegios ao novo usuario
4) restart no SAMBA para a configuração ter algum efeito
Com mais detalhes em (http://www.cyberciti.biz/faq/adding-a-user-to-a-samba-smb-share/):
Step # 1: Add a user joe to UNIX/Linux system
adduser command adds user to the system according to command line options and configuration information in /etc/adduser.conf. They are friendlier front ends to the low level tools like useradd.
Type any one of the following command:
# useradd joe
# passwd joe
OR
adduser joe
Step # 2: Add a user to samba
Now user joe has account on Linux/UNIX box. Use smbpasswd command to specifies that the username following should be added to the local smbpasswd file:
# smbpasswd -a joe
Step # 3: Add a user to a Samba share
By default user gets access to /home/joe from windows system. Let us say you want to give joe access to /data/accounts (make sure directory /data/accounts exists) directory. Open /etc/samba/smb.conf file and add/modify share called [accounts]:
[accounts]comment = Accounts data directorypath = /data/accountsvalid users = vivek raj joepublic = nowritable = yes
Save the file.
Step #4: Restart the samba
# service smb restart
OR
# /etc/init.d/smb reload