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diff --git a/crypto/heimdal/doc/apps.texi b/crypto/heimdal/doc/apps.texi new file mode 100644 index 0000000..9d451b6 --- /dev/null +++ b/crypto/heimdal/doc/apps.texi @@ -0,0 +1,244 @@ +@c $Id: apps.texi 22071 2007-11-14 20:04:50Z lha $ + +@node Applications, Things in search for a better place, Setting up a realm, Top + +@chapter Applications + +@menu +* Authentication modules:: +* AFS:: +@end menu + +@node Authentication modules, AFS, Applications, Applications +@section Authentication modules + +The problem of having different authentication mechanisms has been +recognised by several vendors, and several solutions have appeared. In +most cases these solutions involve some kind of shared modules that are +loaded at run-time. Modules for some of these systems can be found in +@file{lib/auth}. Presently there are modules for Digital's SIA, +and IRIX' @code{login} and @code{xdm} (in +@file{lib/auth/afskauthlib}). + +@menu +* Digital SIA:: +* IRIX:: +@end menu + +@node Digital SIA, IRIX, Authentication modules, Authentication modules +@subsection Digital SIA + +How to install the SIA module depends on which OS version you're +running. Tru64 5.0 has a new command, @file{siacfg}, which makes this +process quite simple. If you have this program, you should just be able +to run: +@example +siacfg -a KRB5 /usr/athena/lib/libsia_krb5.so +@end example + +On older versions, or if you want to do it by hand, you have to do the +following (not tested by us on Tru64 5.0): + +@itemize @bullet + +@item +Make sure @file{libsia_krb5.so} is available in +@file{/usr/athena/lib}. If @file{/usr/athena} is not on local disk, you +might want to put it in @file{/usr/shlib} or someplace else. If you do, +you'll have to edit @file{krb5_matrix.conf} to reflect the new location +(you will also have to do this if you installed in some other directory +than @file{/usr/athena}). If you built with shared libraries, you will +have to copy the shared @file{libkrb.so}, @file{libdes.so}, +@file{libkadm.so}, and @file{libkafs.so} to a place where the loader can +find them (such as @file{/usr/shlib}). +@item +Copy (your possibly edited) @file{krb5_matrix.conf} to @file{/etc/sia}. +@item +Apply @file{security.patch} to @file{/sbin/init.d/security}. +@item +Turn on KRB5 security by issuing @kbd{rcmgr set SECURITY KRB5} and +@kbd{rcmgr set KRB5_MATRIX_CONF krb5_matrix.conf}. +@item +Digital thinks you should reboot your machine, but that really shouldn't +be necessary. It's usually sufficient just to run +@kbd{/sbin/init.d/security start} (and restart any applications that use +SIA, like @code{xdm}.) +@end itemize + +Users with local passwords (like @samp{root}) should be able to login +safely. + +When using Digital's xdm the @samp{KRB5CCNAME} environment variable isn't +passed along as it should (since xdm zaps the environment). Instead you +have to set @samp{KRB5CCNAME} to the correct value in +@file{/usr/lib/X11/xdm/Xsession}. Add a line similar to +@example +KRB5CCNAME=FILE:/tmp/krb5cc`id -u`_`ps -o ppid= -p $$`; export KRB5CCNAME +@end example +If you use CDE, @code{dtlogin} allows you to specify which additional +environment variables it should export. To add @samp{KRB5CCNAME} to this +list, edit @file{/usr/dt/config/Xconfig}, and look for the definition of +@samp{exportList}. You want to add something like: +@example +Dtlogin.exportList: KRB5CCNAME +@end example + +@subsubheading Notes to users with Enhanced security + +Digital's @samp{ENHANCED} (C2) security, and Kerberos solve two +different problems. C2 deals with local security, adds better control of +who can do what, auditing, and similar things. Kerberos deals with +network security. + +To make C2 security work with Kerberos you will have to do the +following. + +@itemize @bullet +@item +Replace all occurrences of @file{krb5_matrix.conf} with +@file{krb5+c2_matrix.conf} in the directions above. +@item +You must enable ``vouching'' in the @samp{default} database. This will +make the OSFC2 module trust other SIA modules, so you can login without +giving your C2 password. To do this use @samp{edauth} to edit the +default entry @kbd{/usr/tcb/bin/edauth -dd default}, and add a +@samp{d_accept_alternate_vouching} capability, if not already present. +@item +For each user who does @emph{not} have a local C2 password, you should +set the password expiration field to zero. You can do this for each +user, or in the @samp{default} table. To do this use @samp{edauth} to +set (or change) the @samp{u_exp} capability to @samp{u_exp#0}. +@item +You also need to be aware that the shipped @file{login}, @file{rcp}, and +@file{rshd}, don't do any particular C2 magic (such as checking for +various forms of disabled accounts), so if you rely on those features, +you shouldn't use those programs. If you configure with +@samp{--enable-osfc2}, these programs will, however, set the login +UID. Still: use at your own risk. +@end itemize + +At present @samp{su} does not accept the vouching flag, so it will not +work as expected. + +Also, kerberised ftp will not work with C2 passwords. You can solve this +by using both Digital's ftpd and our on different ports. + +@strong{Remember}, if you do these changes you will get a system that +most certainly does @emph{not} fulfil the requirements of a C2 +system. If C2 is what you want, for instance if someone else is forcing +you to use it, you're out of luck. If you use enhanced security because +you want a system that is more secure than it would otherwise be, you +probably got an even more secure system. Passwords will not be sent in +the clear, for instance. + +@node IRIX, , Digital SIA, Authentication modules +@subsection IRIX + +The IRIX support is a module that is compatible with Transarc's +@file{afskauthlib.so}. It should work with all programs that use this +library. This should include @command{login} and @command{xdm}. + +The interface is not very documented but it seems that you have to copy +@file{libkafs.so}, @file{libkrb.so}, and @file{libdes.so} to +@file{/usr/lib}, or build your @file{afskauthlib.so} statically. + +The @file{afskauthlib.so} itself is able to reside in +@file{/usr/vice/etc}, @file{/usr/afsws/lib}, or the current directory +(wherever that is). + +IRIX 6.4 and newer seem to have all programs (including @command{xdm} and +@command{login}) in the N32 object format, whereas in older versions they +were O32. For it to work, the @file{afskauthlib.so} library has to be in +the same object format as the program that tries to load it. This might +require that you have to configure and build for O32 in addition to the +default N32. + +Apart from this it should ``just work''; there are no configuration +files. + +Note that recent Irix 6.5 versions (at least 6.5.22) have PAM, +including a @file{pam_krb5.so} module. Not all relevant programs use +PAM, though, e.g.@: @command{ssh}. In particular, for console +graphical login you need to turn off @samp{visuallogin} and turn on +@samp{xdm} with @command{chkconfig}. + +@node AFS, , Authentication modules, Applications +@section AFS + +@cindex AFS +AFS is a distributed filesystem that uses Kerberos for authentication. + +@cindex OpenAFS +@cindex Arla +For more information about AFS see OpenAFS +@url{http://www.openafs.org/} and Arla +@url{http://www.stacken.kth.se/projekt/arla/}. + +@subsection How to get a KeyFile + +@file{ktutil -k AFSKEYFILE:KeyFile get afs@@MY.REALM} + +or you can extract it with kadmin + +@example +kadmin> ext -k AFSKEYFILE:/usr/afs/etc/KeyFile afs@@My.CELL.NAME +@end example + +You have to make sure you have a @code{des-cbc-md5} encryption type since that +is the enctype that will be converted. + +@subsection How to convert a srvtab to a KeyFile + +You need a @file{/usr/vice/etc/ThisCell} containing the cellname of your +AFS-cell. + +@file{ktutil copy krb4:/root/afs-srvtab AFSKEYFILE:/usr/afs/etc/KeyFile}. + +If keyfile already exists, this will add the new key in afs-srvtab to +KeyFile. + +@section Using 2b tokens with AFS + +@subsection What is 2b ? + +2b is the name of the proposal that was implemented to give basic +Kerberos 5 support to AFS in rxkad. It's not real Kerberos 5 support +since it still uses fcrypt for data encryption and not Kerberos +encryption types. + +Its only possible (in all cases) to do this for DES encryption types +because only then the token (the AFS equivalent of a ticket) will be +smaller than the maximum size that can fit in the token cache in the +OpenAFS/Transarc client. It is a so tight fit that some extra wrapping +on the ASN1/DER encoding is removed from the Kerberos ticket. + +2b uses a Kerberos 5 EncTicketPart instead of a Kerberos 4 ditto for +the part of the ticket that is encrypted with the service's key. The +client doesn't know what's inside the encrypted data so to the client +it doesn't matter. + +To differentiate between Kerberos 4 tickets and Kerberos 5 tickets, 2b +uses a special kvno, 213 for 2b tokens and 255 for Kerberos 5 tokens. + +Its a requirement that all AFS servers that support 2b also support +native Kerberos 5 in rxkad. + +@subsection Configuring a Heimdal kdc to use 2b tokens + +Support for 2b tokens in the kdc are turned on for specific principals +by adding them to the string list option @code{[kdc]use_2b} in the +kdc's @file{krb5.conf} file. + +@example +[kdc] + use_2b = @{ + afs@@SU.SE = yes + afs/it.su.se@@SU.SE = yes + @} +@end example + +@subsection Configuring AFS clients for 2b support + +There is no need to configure AFS clients for 2b support. The only +software that needs to be installed/upgrade is a Kerberos 5 enabled +@file{afslog}. |
