1@c $Id: apps.texi 22071 2007-11-14 20:04:50Z lha $ 2 3@node Applications, Things in search for a better place, Setting up a realm, Top 4 5@chapter Applications 6 7@menu 8* Authentication modules:: 9* AFS:: 10@end menu 11 12@node Authentication modules, AFS, Applications, Applications 13@section Authentication modules 14 15The problem of having different authentication mechanisms has been 16recognised by several vendors, and several solutions have appeared. In 17most cases these solutions involve some kind of shared modules that are 18loaded at run-time. Modules for some of these systems can be found in 19@file{lib/auth}. Presently there are modules for Digital's SIA, 20and IRIX' @code{login} and @code{xdm} (in 21@file{lib/auth/afskauthlib}). 22 23@menu 24* Digital SIA:: 25* IRIX:: 26@end menu 27 28@node Digital SIA, IRIX, Authentication modules, Authentication modules 29@subsection Digital SIA 30 31How to install the SIA module depends on which OS version you're 32running. Tru64 5.0 has a new command, @file{siacfg}, which makes this 33process quite simple. If you have this program, you should just be able 34to run: 35@example 36siacfg -a KRB5 /usr/athena/lib/libsia_krb5.so 37@end example 38 39On older versions, or if you want to do it by hand, you have to do the 40following (not tested by us on Tru64 5.0): 41 42@itemize @bullet 43 44@item 45Make sure @file{libsia_krb5.so} is available in 46@file{/usr/athena/lib}. If @file{/usr/athena} is not on local disk, you 47might want to put it in @file{/usr/shlib} or someplace else. If you do, 48you'll have to edit @file{krb5_matrix.conf} to reflect the new location 49(you will also have to do this if you installed in some other directory 50than @file{/usr/athena}). If you built with shared libraries, you will 51have to copy the shared @file{libkrb.so}, @file{libdes.so}, 52@file{libkadm.so}, and @file{libkafs.so} to a place where the loader can 53find them (such as @file{/usr/shlib}). 54@item 55Copy (your possibly edited) @file{krb5_matrix.conf} to @file{/etc/sia}. 56@item 57Apply @file{security.patch} to @file{/sbin/init.d/security}. 58@item 59Turn on KRB5 security by issuing @kbd{rcmgr set SECURITY KRB5} and 60@kbd{rcmgr set KRB5_MATRIX_CONF krb5_matrix.conf}. 61@item 62Digital thinks you should reboot your machine, but that really shouldn't 63be necessary. It's usually sufficient just to run 64@kbd{/sbin/init.d/security start} (and restart any applications that use 65SIA, like @code{xdm}.) 66@end itemize 67 68Users with local passwords (like @samp{root}) should be able to login 69safely. 70 71When using Digital's xdm the @samp{KRB5CCNAME} environment variable isn't 72passed along as it should (since xdm zaps the environment). Instead you 73have to set @samp{KRB5CCNAME} to the correct value in 74@file{/usr/lib/X11/xdm/Xsession}. Add a line similar to 75@example 76KRB5CCNAME=FILE:/tmp/krb5cc`id -u`_`ps -o ppid= -p $$`; export KRB5CCNAME 77@end example 78If you use CDE, @code{dtlogin} allows you to specify which additional 79environment variables it should export. To add @samp{KRB5CCNAME} to this 80list, edit @file{/usr/dt/config/Xconfig}, and look for the definition of 81@samp{exportList}. You want to add something like: 82@example 83Dtlogin.exportList: KRB5CCNAME 84@end example 85 86@subsubheading Notes to users with Enhanced security 87 88Digital's @samp{ENHANCED} (C2) security, and Kerberos solve two 89different problems. C2 deals with local security, adds better control of 90who can do what, auditing, and similar things. Kerberos deals with 91network security. 92 93To make C2 security work with Kerberos you will have to do the 94following. 95 96@itemize @bullet 97@item 98Replace all occurrences of @file{krb5_matrix.conf} with 99@file{krb5+c2_matrix.conf} in the directions above. 100@item 101You must enable ``vouching'' in the @samp{default} database. This will 102make the OSFC2 module trust other SIA modules, so you can login without 103giving your C2 password. To do this use @samp{edauth} to edit the 104default entry @kbd{/usr/tcb/bin/edauth -dd default}, and add a 105@samp{d_accept_alternate_vouching} capability, if not already present. 106@item 107For each user who does @emph{not} have a local C2 password, you should 108set the password expiration field to zero. You can do this for each 109user, or in the @samp{default} table. To do this use @samp{edauth} to 110set (or change) the @samp{u_exp} capability to @samp{u_exp#0}. 111@item 112You also need to be aware that the shipped @file{login}, @file{rcp}, and 113@file{rshd}, don't do any particular C2 magic (such as checking for 114various forms of disabled accounts), so if you rely on those features, 115you shouldn't use those programs. If you configure with 116@samp{--enable-osfc2}, these programs will, however, set the login 117UID. Still: use at your own risk. 118@end itemize 119 120At present @samp{su} does not accept the vouching flag, so it will not 121work as expected. 122 123Also, kerberised ftp will not work with C2 passwords. You can solve this 124by using both Digital's ftpd and our on different ports. 125 126@strong{Remember}, if you do these changes you will get a system that 127most certainly does @emph{not} fulfil the requirements of a C2 128system. If C2 is what you want, for instance if someone else is forcing 129you to use it, you're out of luck. If you use enhanced security because 130you want a system that is more secure than it would otherwise be, you 131probably got an even more secure system. Passwords will not be sent in 132the clear, for instance. 133 134@node IRIX, , Digital SIA, Authentication modules 135@subsection IRIX 136 137The IRIX support is a module that is compatible with Transarc's 138@file{afskauthlib.so}. It should work with all programs that use this 139library. This should include @command{login} and @command{xdm}. 140 141The interface is not very documented but it seems that you have to copy 142@file{libkafs.so}, @file{libkrb.so}, and @file{libdes.so} to 143@file{/usr/lib}, or build your @file{afskauthlib.so} statically. 144 145The @file{afskauthlib.so} itself is able to reside in 146@file{/usr/vice/etc}, @file{/usr/afsws/lib}, or the current directory 147(wherever that is). 148 149IRIX 6.4 and newer seem to have all programs (including @command{xdm} and 150@command{login}) in the N32 object format, whereas in older versions they 151were O32. For it to work, the @file{afskauthlib.so} library has to be in 152the same object format as the program that tries to load it. This might 153require that you have to configure and build for O32 in addition to the 154default N32. 155 156Apart from this it should ``just work''; there are no configuration 157files. 158 159Note that recent Irix 6.5 versions (at least 6.5.22) have PAM, 160including a @file{pam_krb5.so} module. Not all relevant programs use 161PAM, though, e.g.@: @command{ssh}. In particular, for console 162graphical login you need to turn off @samp{visuallogin} and turn on 163@samp{xdm} with @command{chkconfig}. 164 165@node AFS, , Authentication modules, Applications 166@section AFS 167 168@cindex AFS 169AFS is a distributed filesystem that uses Kerberos for authentication. 170 171@cindex OpenAFS 172@cindex Arla 173For more information about AFS see OpenAFS 174@url{http://www.openafs.org/} and Arla 175@url{http://www.stacken.kth.se/projekt/arla/}. 176 177@subsection How to get a KeyFile 178 179@file{ktutil -k AFSKEYFILE:KeyFile get afs@@MY.REALM} 180 181or you can extract it with kadmin 182 183@example 184kadmin> ext -k AFSKEYFILE:/usr/afs/etc/KeyFile afs@@My.CELL.NAME 185@end example 186 187You have to make sure you have a @code{des-cbc-md5} encryption type since that 188is the enctype that will be converted. 189 190@subsection How to convert a srvtab to a KeyFile 191 192You need a @file{/usr/vice/etc/ThisCell} containing the cellname of your 193AFS-cell. 194 195@file{ktutil copy krb4:/root/afs-srvtab AFSKEYFILE:/usr/afs/etc/KeyFile}. 196 197If keyfile already exists, this will add the new key in afs-srvtab to 198KeyFile. 199 200@section Using 2b tokens with AFS 201 202@subsection What is 2b ? 203 2042b is the name of the proposal that was implemented to give basic 205Kerberos 5 support to AFS in rxkad. It's not real Kerberos 5 support 206since it still uses fcrypt for data encryption and not Kerberos 207encryption types. 208 209Its only possible (in all cases) to do this for DES encryption types 210because only then the token (the AFS equivalent of a ticket) will be 211smaller than the maximum size that can fit in the token cache in the 212OpenAFS/Transarc client. It is a so tight fit that some extra wrapping 213on the ASN1/DER encoding is removed from the Kerberos ticket. 214 2152b uses a Kerberos 5 EncTicketPart instead of a Kerberos 4 ditto for 216the part of the ticket that is encrypted with the service's key. The 217client doesn't know what's inside the encrypted data so to the client 218it doesn't matter. 219 220To differentiate between Kerberos 4 tickets and Kerberos 5 tickets, 2b 221uses a special kvno, 213 for 2b tokens and 255 for Kerberos 5 tokens. 222 223Its a requirement that all AFS servers that support 2b also support 224native Kerberos 5 in rxkad. 225 226@subsection Configuring a Heimdal kdc to use 2b tokens 227 228Support for 2b tokens in the kdc are turned on for specific principals 229by adding them to the string list option @code{[kdc]use_2b} in the 230kdc's @file{krb5.conf} file. 231 232@example 233[kdc] 234 use_2b = @{ 235 afs@@SU.SE = yes 236 afs/it.su.se@@SU.SE = yes 237 @} 238@end example 239 240@subsection Configuring AFS clients for 2b support 241 242There is no need to configure AFS clients for 2b support. The only 243software that needs to be installed/upgrade is a Kerberos 5 enabled 244@file{afslog}. 245