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diff --git a/docs/docbook/projdoc/winbind.sgml b/docs/docbook/projdoc/winbind.sgml new file mode 100644 index 00000000000..b496f30dd74 --- /dev/null +++ b/docs/docbook/projdoc/winbind.sgml @@ -0,0 +1,891 @@ +<chapter id="winbind"> + + +<chapterinfo> + <author> + <firstname>Tim</firstname><surname>Potter</surname> + <affiliation> + <orgname>Samba Team</orgname> + <address><email>tpot@linuxcare.com.au</email></address> + </affiliation> + </author> + <author> + <firstname>Andrew</firstname><surname>Trigdell</surname> + <affiliation> + <orgname>Samba Team</orgname> + <address><email>tridge@linuxcare.com.au</email></address> + </affiliation> + </author> + + + <pubdate>16 Oct 2000</pubdate> +</chapterinfo> + +<title>Unified Logons between Windows NT and UNIX using Winbind</title> + +<sect1> + <title>Abstract</title> + + <para>Integration of UNIX and Microsoft Windows NT through + a unified logon has been considered a "holy grail" in heterogeneous + computing environments for a long time. We present + <emphasis>winbind</emphasis>, a component of the Samba suite + of programs as a solution to the unified logon problem. Winbind + uses a UNIX implementation + of Microsoft RPC calls, Pluggable Authentication Modules, and the Name + Service Switch to allow Windows NT domain users to appear and operate + as UNIX users on a UNIX machine. This paper describes the winbind + system, explaining the functionality it provides, how it is configured, + and how it works internally.</para> +</sect1> + + +<sect1> + <title>Introduction</title> + + <para>It is well known that UNIX and Microsoft Windows NT have + different models for representing user and group information and + use different technologies for implementing them. This fact has + made it difficult to integrate the two systems in a satisfactory + manner.</para> + + <para>One common solution in use today has been to create + identically named user accounts on both the UNIX and Windows systems + and use the Samba suite of programs to provide file and print services + between the two. This solution is far from perfect however, as + adding and deleting users on both sets of machines becomes a chore + and two sets of passwords are required both of which + can lead to synchronization problems between the UNIX and Windows + systems and confusion for users.</para> + + <para>We divide the unified logon problem for UNIX machines into + three smaller problems:</para> + + <itemizedlist> + <listitem><para>Obtaining Windows NT user and group information + </para></listitem> + + <listitem><para>Authenticating Windows NT users + </para></listitem> + + <listitem><para>Password changing for Windows NT users + </para></listitem> + </itemizedlist> + + + <para>Ideally, a prospective solution to the unified logon problem + would satisfy all the above components without duplication of + information on the UNIX machines and without creating additional + tasks for the system administrator when maintaining users and + groups on either system. The winbind system provides a simple + and elegant solution to all three components of the unified logon + problem.</para> +</sect1> + + +<sect1> + <title>What Winbind Provides</title> + + <para>Winbind unifies UNIX and Windows NT account management by + allowing a UNIX box to become a full member of a NT domain. Once + this is done the UNIX box will see NT users and groups as if + they were native UNIX users and groups, allowing the NT domain + to be used in much the same manner that NIS+ is used within + UNIX-only environments.</para> + + <para>The end result is that whenever any + program on the UNIX machine asks the operating system to lookup + a user or group name, the query will be resolved by asking the + NT domain controller for the specified domain to do the lookup. + Because Winbind hooks into the operating system at a low level + (via the NSS name resolution modules in the C library) this + redirection to the NT domain controller is completely + transparent.</para> + + <para>Users on the UNIX machine can then use NT user and group + names as they would use "native" UNIX names. They can chown files + so that they are owned by NT domain users or even login to the + UNIX machine and run a UNIX X-Window session as a domain user.</para> + + <para>The only obvious indication that Winbind is being used is + that user and group names take the form DOMAIN\user and + DOMAIN\group. This is necessary as it allows Winbind to determine + that redirection to a domain controller is wanted for a particular + lookup and which trusted domain is being referenced.</para> + + <para>Additionally, Winbind provides an authentication service + that hooks into the Pluggable Authentication Modules (PAM) system + to provide authentication via a NT domain to any PAM enabled + applications. This capability solves the problem of synchronizing + passwords between systems since all passwords are stored in a single + location (on the domain controller).</para> + + <sect2> + <title>Target Uses</title> + + <para>Winbind is targeted at organizations that have an + existing NT based domain infrastructure into which they wish + to put UNIX workstations or servers. Winbind will allow these + organizations to deploy UNIX workstations without having to + maintain a separate account infrastructure. This greatly + simplifies the administrative overhead of deploying UNIX + workstations into a NT based organization.</para> + + <para>Another interesting way in which we expect Winbind to + be used is as a central part of UNIX based appliances. Appliances + that provide file and print services to Microsoft based networks + will be able to use Winbind to provide seamless integration of + the appliance into the domain.</para> + </sect2> +</sect1> + + + +<sect1> + <title>How Winbind Works</title> + + <para>The winbind system is designed around a client/server + architecture. A long running <command>winbindd</command> daemon + listens on a UNIX domain socket waiting for requests + to arrive. These requests are generated by the NSS and PAM + clients and processed sequentially.</para> + + <para>The technologies used to implement winbind are described + in detail below.</para> + + <sect2> + <title>Microsoft Remote Procedure Calls</title> + + <para>Over the last two years, efforts have been underway + by various Samba Team members to decode various aspects of + the Microsoft Remote Procedure Call (MSRPC) system. This + system is used for most network related operations between + Windows NT machines including remote management, user authentication + and print spooling. Although initially this work was done + to aid the implementation of Primary Domain Controller (PDC) + functionality in Samba, it has also yielded a body of code which + can be used for other purposes.</para> + + <para>Winbind uses various MSRPC calls to enumerate domain users + and groups and to obtain detailed information about individual + users or groups. Other MSRPC calls can be used to authenticate + NT domain users and to change user passwords. By directly querying + a Windows PDC for user and group information, winbind maps the + NT account information onto UNIX user and group names.</para> + </sect2> + + <sect2> + <title>Name Service Switch</title> + + <para>The Name Service Switch, or NSS, is a feature that is + present in many UNIX operating systems. It allows system + information such as hostnames, mail aliases and user information + to be resolved from different sources. For example, a standalone + UNIX workstation may resolve system information from a series of + flat files stored on the local filesystem. A networked workstation + may first attempt to resolve system information from local files, + and then consult a NIS database for user information or a DNS server + for hostname information.</para> + + <para>The NSS application programming interface allows winbind + to present itself as a source of system information when + resolving UNIX usernames and groups. Winbind uses this interface, + and information obtained from a Windows NT server using MSRPC + calls to provide a new source of account enumeration. Using standard + UNIX library calls, one can enumerate the users and groups on + a UNIX machine running winbind and see all users and groups in + a NT domain plus any trusted domain as though they were local + users and groups.</para> + + <para>The primary control file for NSS is + <filename>/etc/nsswitch.conf</filename>. + When a UNIX application makes a request to do a lookup + the C library looks in <filename>/etc/nsswitch.conf</filename> + for a line which matches the service type being requested, for + example the "passwd" service type is used when user or group names + are looked up. This config line species which implementations + of that service should be tried and in what order. If the passwd + config line is:</para> + + <para><command>passwd: files example</command></para> + + <para>then the C library will first load a module called + <filename>/lib/libnss_files.so</filename> followed by + the module <filename>/lib/libnss_example.so</filename>. The + C library will dynamically load each of these modules in turn + and call resolver functions within the modules to try to resolve + the request. Once the request is resolved the C library returns the + result to the application.</para> + + <para>This NSS interface provides a very easy way for Winbind + to hook into the operating system. All that needs to be done + is to put <filename>libnss_winbind.so</filename> in <filename>/lib/</filename> + then add "winbind" into <filename>/etc/nsswitch.conf</filename> at + the appropriate place. The C library will then call Winbind to + resolve user and group names.</para> + </sect2> + + <sect2> + <title>Pluggable Authentication Modules</title> + + <para>Pluggable Authentication Modules, also known as PAM, + is a system for abstracting authentication and authorization + technologies. With a PAM module it is possible to specify different + authentication methods for different system applications without + having to recompile these applications. PAM is also useful + for implementing a particular policy for authorization. For example, + a system administrator may only allow console logins from users + stored in the local password file but only allow users resolved from + a NIS database to log in over the network.</para> + + <para>Winbind uses the authentication management and password + management PAM interface to integrate Windows NT users into a + UNIX system. This allows Windows NT users to log in to a UNIX + machine and be authenticated against a suitable Primary Domain + Controller. These users can also change their passwords and have + this change take effect directly on the Primary Domain Controller. + </para> + + <para>PAM is configured by providing control files in the directory + <filename>/etc/pam.d/</filename> for each of the services that + require authentication. When an authentication request is made + by an application the PAM code in the C library looks up this + control file to determine what modules to load to do the + authentication check and in what order. This interface makes adding + a new authentication service for Winbind very easy, all that needs + to be done is that the <filename>pam_winbind.so</filename> module + is copied to <filename>/lib/security/</filename> and the PAM + control files for relevant services are updated to allow + authentication via winbind. See the PAM documentation + for more details.</para> + </sect2> + + + <sect2> + <title>User and Group ID Allocation</title> + + <para>When a user or group is created under Windows NT + is it allocated a numerical relative identifier (RID). This is + slightly different to UNIX which has a range of numbers that are + used to identify users, and the same range in which to identify + groups. It is winbind's job to convert RIDs to UNIX id numbers and + vice versa. When winbind is configured it is given part of the UNIX + user id space and a part of the UNIX group id space in which to + store Windows NT users and groups. If a Windows NT user is + resolved for the first time, it is allocated the next UNIX id from + the range. The same process applies for Windows NT groups. Over + time, winbind will have mapped all Windows NT users and groups + to UNIX user ids and group ids.</para> + + <para>The results of this mapping are stored persistently in + an ID mapping database held in a tdb database). This ensures that + RIDs are mapped to UNIX IDs in a consistent way.</para> + </sect2> + + + <sect2> + <title>Result Caching</title> + + <para>An active system can generate a lot of user and group + name lookups. To reduce the network cost of these lookups winbind + uses a caching scheme based on the SAM sequence number supplied + by NT domain controllers. User or group information returned + by a PDC is cached by winbind along with a sequence number also + returned by the PDC. This sequence number is incremented by + Windows NT whenever any user or group information is modified. If + a cached entry has expired, the sequence number is requested from + the PDC and compared against the sequence number of the cached entry. + If the sequence numbers do not match, then the cached information + is discarded and up to date information is requested directly + from the PDC.</para> + </sect2> +</sect1> + + +<sect1> + <title>Installation and Configuration</title> + +<para> +Many thanks to John Trostel <ulink +url="mailto:jtrostel@snapserver.com">jtrostel@snapserver.com</ulink> +for providing the HOWTO for this section. +</para> + +<para> +This HOWTO describes how to get winbind services up and running +to control access and authenticate users on your Linux box using +the winbind services which come with SAMBA 2.2.2. +</para> + + +<sect2> +<title>Introduction</title> + +<para> +This HOWTO describes the procedures used to get winbind up and +running on my RedHat 7.1 system. Winbind is capable of providing access +and authentication control for Windows Domain users through an NT +or Win2K PDC for 'regular' services, such as telnet a nd ftp, as +well for SAMBA services. +</para> + +<para> +This HOWTO has been written from a 'RedHat-centric' perspective, so if +you are using another distribution, you may have to modify the instructions +somewhat to fit the way your distribution works. +</para> + + +<itemizedlist> +<listitem> + <para> + <emphasis>Why should I to this?</emphasis> + </para> + + <para>This allows the SAMBA administrator to rely on the + authentication mechanisms on the NT/Win2K PDC for the authentication + of domain members. NT/Win2K users no longer need to have separate + accounts on the SAMBA server. + </para> +</listitem> + +<listitem> + <para> + <emphasis>Who should be reading this document?</emphasis> + </para> + + <para> + This HOWTO is designed for system administrators. If you are + implementing SAMBA on a file server and wish to (fairly easily) + integrate existing NT/Win2K users from your PDC onto the + SAMBA server, this HOWTO is for you. That said, I am no NT or PAM + expert, so you may find a better or easier way to accomplish + these tasks. + </para> +</listitem> +</itemizedlist> +</sect2> + + +<sect2> +<title>Requirements</title> + +<para> +If you have a samba configuration file that you are currently +using... BACK IT UP! If your system already uses PAM, BACK UP +THE <filename>/etc/pam.d</filename> directory contents! If you +haven't already made a boot disk, MAKE ON NOW! +</para> + +<para> +Messing with the pam configuration files can make it nearly impossible +to log in to yourmachine. That's why you want to be able to boot back +into your machine in single user mode and restore your +<filename>/etc/pam.d</filename> back to the original state they were in if +you get frustrated with the way things are going. ;-) +</para> + +<para> +The newest version of SAMBA (version 2.2.2), available from +cvs.samba.org, now include a functioning winbindd daemon. Please refer +to the main SAMBA web page or, better yet, your closest SAMBA mirror +site for instructions on downloading the source code. +</para> + +<para> +To allow Domain users the ability to access SAMBA shares and +files, as well as potentially other services provided by your +SAMBA machine, PAM (pluggable authentication modules) must +be setup properly on your machine. In order to compile the +winbind modules, you should have at least the pam libraries resident +on your system. For recent RedHat systems (7.1, for instance), that +means 'pam-0.74-22'. For best results, it is helpful to also +install the development packages in 'pam-devel-0.74-22'. +</para> + +</sect2> + + +<sect2> +<title>Testing Things Out</title> + +<para> +Before starting, it is probably best to kill off all the SAMBA +related daemons running on your server. Kill off all <command>smbd</command>, +<command>nmbd</command>, and <command>winbindd</command> processes that may +be running. To use PAM, you will want to make sure that you have the +standard PAM package (for RedHat) which supplies the <filename>/etc/pam.d</filename> +directory structure, including the pam modules are used by pam-aware +services, several pam libraries, and the <filename>/usr/doc</filename> +and <filename>/usr/man</filename> entries for pam. Winbind built better +in SAMBA if the pam-devel package was also installed. This package includes +the header files needed to compile pam-aware applications. For instance, my RedHat +system has both 'pam-0.74-22' and 'pam-devel-0.74-22' RPMs installed. +</para> + +<sect3> +<title>Configure and compile SAMBA</title> + +<para> +The configuration and compilation of SAMBA is pretty straightforward. +The first three steps maynot be necessary depending upon +whether or not you have previously built the Samba binaries. +</para> + +<para><programlisting> +<prompt>root# </prompt> autoconf +<prompt>root# </prompt> make clean +<prompt>root# </prompt> rm config.cache +<prompt>root# </prompt> ./configure --with-winbind +<prompt>root# </prompt> make +<prompt>root# </prompt> make install +</programlisting></para> + + +<para> +This will, by default, install SAMBA in /usr/local/samba. See the +main SAMBA documentation if you want to install SAMBA somewhere else. +It will also build the winbindd executable and libraries. +</para> + +</sect3> + +<sect3> +<title>Configure nsswitch.conf and the winbind libraries</title> + +<para> +The libraries needed to run the winbind daemon through nsswitch +need to be copied to their proper locations, so +</para> + +<para> +<prompt>root# </prompt> cp ../samba/source/nsswitch/libnss_winbind.so /lib +</para> + +<para> +I also found it necessary to make the following symbolic link: +</para> + +<para> +<prompt>root# </prompt> ln -s /lib/libnss_winbind.so /lib/libnss_winbind.so.2 +</para> + +<para> +Now, as root you need to edit <filename>/etc/nsswitch.conf</filename> to +allow user and group entries to be visible from the <command>winbindd</command> +daemon, as well as from your /etc/hosts files and NIS servers. My +<filename>/etc/nsswitch.conf</filename> file look like this after editing: +</para> + +<para><programlisting> + passwd: files winbind + shadow: files winbind + group: files winbind +</programlisting></para> + +<para> +The libraries needed by the winbind daemon will be automatically +entered into the ldconfig cache the next time your system reboots, but it +is faster (and you don't need to reboot) if you do it manually: +</para> + +<para> +<prompt>root# </prompt> /sbin/ldconfig -v | grep winbind +</para> + +<para> +This makes <filename>libnss_winbind</filename> available to winbindd +and echos back a check to you. +</para> + +</sect3> + + +<sect3> +<title>Configure smb.conf</title> + +<para> +Several parameters are needed in the smb.conf file to control +the behavior of <command>winbindd</command>. Configure +<filename>smb.conf</filename> These are described in more detail in +the <ulink url="winbindd.8.html">winbindd(8)</ulink> man page. My +<filename>smb.conf</filename> file was modified to +include the following entries in the [global] section: +</para> + +<para><programlisting> +[global] + <...> + # separate domain and username with '+', like DOMAIN+username + winbind separator = + + # use uids from 10000 to 20000 for domain users + winbind uid = 10000-20000 + # use gids from 10000 to 20000 for domain groups + winbind gid = 10000-20000 + # allow enumeration of winbind users and groups + winbind enum users = yes + winbind enum groups = yes + # give winbind users a real shell (only needed if they have telnet access) + template shell = /bin/bash +</programlisting></para> + +</sect3> + + +<sect3> +<title>Join the SAMBA server to the PDC domain</title> + +<para> +Enter the following command to make the SAMBA server join the +PDC domain, where <replaceable>DOMAIN</replaceable> is the name of +your Windows domain and <replaceable>Administrator</replaceable> is +a domain user who has administrative privileges in the domain. +</para> + + +<para> +<prompt>root# </prompt>/usr/local/samba/bin/smbpasswd -j DOMAIN -r PDC -U Administrator +</para> + + +<para> +The proper response to the command should be: "Joined the domain +<replaceable>DOMAIN</replaceable>" where <replaceable>DOMAIN</replaceable> +is your DOMAIN name. +</para> + +</sect3> + + +<sect3> +<title>Start up the winbindd daemon and test it!</title> + +<para> +Eventually, you will want to modify your smb startup script to +automatically invoke the winbindd daemon when the other parts of +SAMBA start, but it is possible to test out just the winbind +portion first. To start up winbind services, enter the following +command as root: +</para> + +<para> +<prompt>root# </prompt>/usr/local/samba/bin/winbindd +</para> + +<para> +I'm always paranoid and like to make sure the daemon +is really running... +</para> + +<para> +<prompt>root# </prompt> ps -ae | grep winbindd +3025 ? 00:00:00 winbindd +</para> + +<para> +Now... for the real test, try to get some information about the +users on your PDC +</para> + +<para> +<prompt>root# </prompt> # /usr/local/samba/bin/wbinfo -u +</para> + +<para> +This should echo back a list of users on your Windows users on +your PDC. For example, I get the following response: +</para> + +<para><programlisting> +CEO+Administrator +CEO+burdell +CEO+Guest +CEO+jt-ad +CEO+krbtgt +CEO+TsInternetUser +</programlisting></para> + +<para> +Obviously, I have named my domain 'CEO' and my winbindd separator is '+'. +</para> + +<para> +You can do the same sort of thing to get group information from +the PDC: +</para> + +<para><programlisting> +<prompt>root# </prompt>/usr/local/samba/bin/wbinfo -g +CEO+Domain Admins +CEO+Domain Users +CEO+Domain Guests +CEO+Domain Computers +CEO+Domain Controllers +CEO+Cert Publishers +CEO+Schema Admins +CEO+Enterprise Admins +CEO+Group Policy Creator Owners +</programlisting></para> + +<para> +The function 'getent' can now be used to get unified +lists of both local and PDC users and groups. +Try the following command: +</para> + +<para> +<prompt>root# </prompt> getent passwd +</para> + +<para> +You should get a list that looks like your <filename>/etc/passwd</filename> +list followed by the domain users with their new uids, gids, home +directories and default shells. +</para> + +<para> +The same thing can be done for groups with the command +</para> + +<para> +<prompt>root# </prompt> getent group +</para> + +</sect3> + + +<sect3> +<title>Fix the /etc/rc.d/init.d/smb startup files</title> + +<para> +The <command>winbindd</command> daemon needs to start up after the +<command>smbd</command> and <command>nmbd</command> daemons are running. +To accomplish this task, you need to modify the <filename>/etc/init.d/smb</filename> +script to add commands to invoke this daemon in the proper sequence. My +<filename>/etc/init.d/smb</filename> file starts up <command>smbd</command>, +<command>nmbd</command>, and <command>winbindd</command> from the +<filename>/usr/local/samba/bin</filename> directory directly. The 'start' +function in the script looks like this: +</para> + +<para><programlisting> +start() { + KIND="SMB" + echo -n $"Starting $KIND services: " + daemon /usr/local/samba/bin/smbd $SMBDOPTIONS + RETVAL=$? + echo + KIND="NMB" + echo -n $"Starting $KIND services: " + daemon /usr/local/samba/bin/nmbd $NMBDOPTIONS + RETVAL2=$? + echo + KIND="Winbind" + echo -n $"Starting $KIND services: " + daemon /usr/local/samba/bin/winbindd + RETVAL3=$? + echo + [ $RETVAL -eq 0 -a $RETVAL2 -eq 0 -a $RETVAL3 -eq 0 ] && touch /var/lock/subsys/smb || \ + RETVAL=1 + return $RETVAL +} +</programlisting></para> + +<para> +The 'stop' function has a corresponding entry to shut down the +services and look s like this: +</para> + +<para><programlisting> +stop() { + KIND="SMB" + echo -n $"Shutting down $KIND services: " + killproc smbd + RETVAL=$? + echo + KIND="NMB" + echo -n $"Shutting down $KIND services: " + killproc nmbd + RETVAL2=$? + echo + KIND="Winbind" + echo -n $"Shutting down $KIND services: " + killproc winbindd + RETVAL3=$? + [ $RETVAL -eq 0 -a $RETVAL2 -eq 0 -a $RETVAL3 -eq 0 ] && rm -f /var/lock/subsys/smb + echo "" + return $RETVAL +} +</programlisting></para> + +</sect3> + + + +<sect3> +<title>Configure Winbind and PAM</title> + +<para> +If you have made it this far, you know that winbindd is working. +Now it is time to integrate it into the operation of samba and other +services. The pam configuration files need to be altered in +this step. (Did you remember to make backups of your original +<filename>/etc/pam.d</filename> files? If not, do it now.) +</para> + +<para> +To get samba to allow domain users and groups, I modified the +<filename>/etc/pam.d/samba</filename> file from +</para> + + +<para><programlisting> +auth required /lib/security/pam_stack.so service=system-auth +account required /lib/security/pam_stack.so service=system-auth +</programlisting></para> + +<para> +to +</para> + +<para><programlisting> +auth required /lib/security/pam_winbind.so +auth required /lib/security/pam_stack.so service=system-auth +account required /lib/security/pam_winbind.so +account required /lib/security/pam_stack.so service=system-auth +</programlisting></para> + +<para> +The other services that I modified to allow the use of winbind +as an authentication service were the normal login on the console (or a terminal +session), telnet logins, and ftp service. In order to enable these +services, you may first need to change the entries in +<filename>/etc/xinetd.d</filename> (or <filename>/etc/inetd.conf</filename>). +RedHat 7.1 uses the new xinetd.d structure, in this case you need +to change the lines in <filename>/etc/xinetd.d/telnet</filename> +and <filename>/etc/xinetd.d/wu-ftp</filename> from +</para> + +<para><programlisting> +enable = no +</programlisting></para> + +<para> +to +</para> + +<para><programlisting> +enable = yes +</programlisting></para> + +<para> +For ftp services to work properly, you will also need to either +have individual directories for the domain users already present on +the server, or change the home directory template to a general +directory for all domain users. These can be easily set using +the <filename>smb.conf</filename> global entry +<command>template homedir</command>. +</para> + +<para> +The <filename>/etc/pam.d/ftp</filename> file can be changed +to allow winbind ftp access in a manner similar to the +samba file. My <filename>/etc/pam.d/ftp</filename> file was +changed to look like this: +</para> + +<para><programlisting> +auth sufficient /lib/security/pam_winbind.so +auth required /lib/security/pam_listfile.so item=user sense=deny file=/etc/ftpusers onerr=succeed +auth required /lib/security/pam_stack.so service=system-auth +auth required /lib/security/pam_shells.so +account required /lib/security/pam_stack.so service=system-auth +session required /lib/security/pam_stack.so service=system-auth +</programlisting></para> + +<para> +The <filename>/etc/pam.d/login</filename> file can be changed nearly the +same way. It now looks like this: +</para> + +<para><programlisting> +auth required /lib/security/pam_securetty.so +auth sufficient /lib/security/pam_winbind.so +auth sufficient /lib/security/pam_unix.so use_first_pass +auth required /lib/security/pam_stack.so service=system-auth +auth required /lib/security/pam_nologin.so +account sufficient /lib/security/pam_winbind.so +account required /lib/security/pam_stack.so service=system-auth +password required /lib/security/pam_stack.so service=system-auth +session required /lib/security/pam_stack.so service=system-auth +session optional /lib/security/pam_console.so +</programlisting></para> + +<para> +In this case, I added the <command>auth sufficient /lib/security/pam_winbind.so</command> +lines as before, but also added the <command>required pam_securetty.so</command> +above it, to disallow root logins over the network. I also added a +<command>sufficient /lib/security/pam_unix.so use_first_pass</command> +line after the <command>winbind.so</command> line to get rid of annoying +double prompts for passwords. +</para> + +<para> +Finally, don't forget to copy the winbind pam modules from +the source directory in which you originally compiled the new +SAMBA up to the /lib/security directory so that pam can use it: +</para> + +<para> +<prompt>root# </prompt> cp ../samba/source/nsswitch/pam_winbind.so /lib/security +</para> + +</sect3> + +</sect2> + +</sect1> + +<sect1> + <title>Limitations</title> + + <para>Winbind has a number of limitations in its current + released version that we hope to overcome in future + releases:</para> + + <itemizedlist> + <listitem><para>Winbind is currently only available for + the Linux operating system, although ports to other operating + systems are certainly possible. For such ports to be feasible, + we require the C library of the target operating system to + support the Name Service Switch and Pluggable Authentication + Modules systems. This is becoming more common as NSS and + PAM gain support among UNIX vendors.</para></listitem> + + <listitem><para>The mappings of Windows NT RIDs to UNIX ids + is not made algorithmically and depends on the order in which + unmapped users or groups are seen by winbind. It may be difficult + to recover the mappings of rid to UNIX id mapping if the file + containing this information is corrupted or destroyed.</para> + </listitem> + + <listitem><para>Currently the winbind PAM module does not take + into account possible workstation and logon time restrictions + that may be been set for Windows NT users.</para></listitem> + </itemizedlist> +</sect1> + + +<sect1> + <title>Conclusion</title> + + <para>The winbind system, through the use of the Name Service + Switch, Pluggable Authentication Modules, and appropriate + Microsoft RPC calls have allowed us to provide seamless + integration of Microsoft Windows NT domain users on a + UNIX system. The result is a great reduction in the administrative + cost of running a mixed UNIX and NT network.</para> + +</sect1> + +</chapter> |