2 @c $NetBSD: win2k.texi,v 1.1.1.3 2014/04/24 12:45:27 pettai Exp $
5 @node Windows compatibility, Programming with Kerberos, Kerberos 4 issues, Top
6 @comment node-name, next, previous, up
7 @chapter Windows compatibility
9 Microsoft Windows, starting from version 2000 (formerly known as Windows NT 5), implements Kerberos 5. Their implementation, however, has some quirks,
10 peculiarities, and bugs. This chapter is a short summary of the compatibility
11 issues between Heimdal and various Windows versions.
13 The big problem with the Kerberos implementation in Windows
14 is that the available documentation is more focused on getting
15 things to work rather than how they work, and not that useful in figuring
16 out how things really work. It's of course subject to change all the time and
17 mostly consists of our not so inspired guesses. Hopefully it's still
21 * Configuring Windows to use a Heimdal KDC::
22 * Inter-Realm keys (trust) between Windows and a Heimdal KDC::
23 * Create account mappings::
25 * Authorisation data::
26 * Quirks of Windows 2000 KDC::
27 * Useful links when reading about the Windows::
30 @node Configuring Windows to use a Heimdal KDC, Inter-Realm keys (trust) between Windows and a Heimdal KDC, Windows compatibility, Windows compatibility
31 @comment node-name, next, precious, up
32 @section Configuring Windows to use a Heimdal KDC
34 You need the command line program called @command{ksetup.exe}. This program comes with the Windows Support Tools, available from either the installation CD-ROM (@file{SUPPORT/TOOLS/SUPPORT.CAB}), or from Microsoft web site. Starting from Windows 2008, it is already installed. This program is used to configure the Kerberos settings on a Workstation.
36 @command{Ksetup} store the domain information under the registry key:
37 @code{HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA\Kerberos\Domains}.
39 Use the @command{kadmin} program in Heimdal to create a host principal in the
44 kadmin> ank --password=password host/datan.example.com
47 The name @samp{datan.example.com} should be replaced with DNS name of
50 You must configure the workstation as a member of a workgroup, as opposed
51 to a member in an NT domain, and specify the KDC server of the realm
54 C:> ksetup /setdomain EXAMPLE.COM
55 C:> ksetup /addkdc EXAMPLE.COM kdc.example.com
58 Set the machine password, i.e.@: create the local keytab:
60 C:> ksetup /SetComputerPassword password
63 The password used in @kbd{ksetup /setmachpassword} must be the same
64 as the password used in the @kbd{kadmin ank} command.
66 The workstation must now be rebooted.
68 A mapping between local NT users and Kerberos principals must be specified.
69 You have two choices. First:
72 C:> ksetup /mapuser user@@MY.REALM nt_user
75 This will map a user to a specific principal; this allows you to have
76 other usernames in the realm than in your NT user database. (Don't ask
77 me why on earth you would want that@enddots{})
81 C:> ksetup /mapuser * *
83 The Windows machine will now map any user to the corresponding principal,
84 for example @samp{nisse} to the principal @samp{nisse@@MY.REALM}.
85 (This is most likely what you want.)
87 @node Inter-Realm keys (trust) between Windows and a Heimdal KDC, Create account mappings, Configuring Windows to use a Heimdal KDC, Windows compatibility
88 @comment node-name, next, precious, up
89 @section Inter-Realm keys (trust) between Windows and a Heimdal KDC
91 See also the Step-by-Step guide from Microsoft, referenced below.
93 Install Windows, and create a new controller (Active Directory
94 Server) for the domain.
96 By default the trust will be non-transitive. This means that only users
97 directly from the trusted domain may authenticate. This can be changed
98 to transitive by using the @command{netdom.exe} tool. @command{netdom.exe}
99 can also be used to add the trust between two realms.
101 You need to tell Windows on what hosts to find the KDCs for the
102 non-Windows realm with @command{ksetup}, see @xref{Configuring Windows
103 to use a Heimdal KDC}.
105 This needs to be done on all computers that want enable cross-realm
106 login with @code{Mapped Names}. @c XXX probably shouldn't be @code
108 Then you need to add the inter-realm keys on the Windows KDC@. Start the
109 Domain Tree Management tool (found in Programs, Administrative tools,
110 Active Directory Domains and Trusts).
112 Right click on Properties of your domain, select the Trust tab. Press
113 Add on the appropriate trust windows and enter domain name and
114 password. When prompted if this is a non-Windows Kerberos realm, press
117 Do not forget to add trusts in both directions (if that's what you want).
119 If you want to use @command{netdom.exe} instead of the Domain Tree
120 Management tool, you do it like this:
123 netdom trust NT.REALM.EXAMPLE.COM /Domain:EXAMPLE.COM /add /realm /passwordt:TrustPassword
126 You also need to add the inter-realm keys to the Heimdal KDC. But take
127 care to the encryption types and salting used for those keys. There should be
128 no encryption type stronger than the one configured on Windows side for this
129 relationship, itself limited to the ones supported by this specific version of
130 Windows, nor any Kerberos 4 salted hashes, as Windows does not seem to
131 understand them. Otherwise, the trust will not works.
133 Here are the version-specific needed information:
135 @item Windows 2000: maximum encryption type is DES
136 @item Windows 2003: maximum encryption type is DES
137 @item Windows 2003RC2: maximum encryption type is RC4, relationship defaults to DES
138 @item Windows 2008: maximum encryption type is AES, relationship defaults to RC4
141 For Windows 2003RC2, to change the trust encryption type, you have to use the
142 @command{ktpass}, from the Windows 2003 Resource kit *service pack2*, available
143 from Microsoft web site.
146 C:> ktpass /MITRealmName UNIX.EXAMPLE.COM /TrustEncryp RC4
149 For Windows 2008, the same operation can be done with the @command{ksetup}, installed by default.
152 C:> ksetup /SetEncTypeAttre EXAMPLE.COM AES256-SHA1
155 Once the relationship is correctly configured, you can add the required
156 inter-realm keys, using heimdal default encryption types:
159 kadmin add krbtgt/NT.REALM.EXAMPLE.COM@@EXAMPLE.COM
160 kadmin add krbtgt/REALM.EXAMPLE.COM@@NT.EXAMPLE.COM
163 Use the same passwords for both keys.
165 And if needed, to remove unsupported encryptions, such as the following ones for a Windows 2003RC2 server.
168 kadmin del_enctype krbtgt/REALM.EXAMPLE.COM@@NT.EXAMPLE.COM aes256-cts-hmac-sha1-96
169 kadmin del_enctype krbtgt/REALM.EXAMPLE.COM@@NT.EXAMPLE.COM des3-cbc-sha1
170 kadmin del_enctype krbtgt/NT.EXAMPLE.COM@@EXAMPLE.COM aes256-cts-hmac-sha1-96
171 kadmin del_enctype krbtgt/NT.EXAMPLE.COM@@EXAMPLE.COM des3-cbc-sha1
174 Do not forget to reboot before trying the new realm-trust (after
175 running @command{ksetup}). It looks like it might work, but packets are
176 never sent to the non-Windows KDC.
178 @node Create account mappings, Encryption types, Inter-Realm keys (trust) between Windows and a Heimdal KDC, Windows compatibility
179 @comment node-name, next, precious, up
180 @section Create account mappings
182 Start the @code{Active Directory Users and Computers} tool. Select the
183 View menu, that is in the left corner just below the real menu (or press
184 Alt-V), and select Advanced Features. Right click on the user that you
185 are going to do a name mapping for and choose Name mapping.
187 Click on the Kerberos Names tab and add a new principal from the
190 @c XXX check entry name then I have network again
191 This adds @samp{authorizationNames} entry to the users LDAP entry to
192 the Active Directory LDAP catalog. When you create users by script you
193 can add this entry instead.
195 @node Encryption types, Authorisation data, Create account mappings, Windows compatibility
196 @comment node-name, next, previous, up
197 @section Encryption types
199 Windows 2000 supports both the standard DES encryptions (@samp{des-cbc-crc} and
200 @samp{des-cbc-md5}) and its own proprietary encryption that is based on MD4 and
201 RC4 that is documented in and is supposed to be described in
202 @file{draft-brezak-win2k-krb-rc4-hmac-03.txt}. New users will get both
203 MD4 and DES keys. Users that are converted from a NT4 database, will
204 only have MD4 passwords and will need a password change to get a DES
207 @node Authorisation data, Quirks of Windows 2000 KDC, Encryption types, Windows compatibility
208 @comment node-name, next, previous, up
209 @section Authorisation data
211 The Windows 2000 KDC also adds extra authorisation data in tickets.
212 It is at this point unclear what triggers it to do this. The format of
213 this data is only available under a ``secret'' license from Microsoft,
214 which prohibits you implementing it.
216 A simple way of getting hold of the data to be able to understand it
217 better is described here.
220 @item Find the client example on using the SSPI in the SDK documentation.
221 @item Change ``AuthSamp'' in the source code to lowercase.
222 @item Build the program.
223 @item Add the ``authsamp'' principal with a known password to the
224 database. Make sure it has a DES key.
225 @item Run @kbd{ktutil add} to add the key for that principal to a
227 @item Run @kbd{appl/test/nt_gss_server -p 2000 -s authsamp
228 @kbd{--dump-auth}=@var{file}} where @var{file} is an appropriate file.
229 @item It should authenticate and dump for you the authorisation data in
231 @item The tool @kbd{lib/asn1/asn1_print} is somewhat useful for
235 @node Quirks of Windows 2000 KDC, Useful links when reading about the Windows, Authorisation data, Windows compatibility
236 @comment node-name, next, previous, up
237 @section Quirks of Windows 2000 KDC
239 There are some issues with salts and Windows 2000. Using an empty salt---which is the only one that Kerberos 4 supported, and is therefore known
240 as a Kerberos 4 compatible salt---does not work, as far as we can tell
241 from out experiments and users' reports. Therefore, you have to make
242 sure you keep around keys with all the different types of salts that are
243 required. Microsoft have fixed this issue post Windows 2003.
245 Microsoft seems also to have forgotten to implement the checksum
246 algorithms @samp{rsa-md4-des} and @samp{rsa-md5-des}. This can make Name
247 mapping (@pxref{Create account mappings}) fail if a @samp{des-cbc-md5} key
248 is used. To make the KDC return only @samp{des-cbc-crc} you must delete
249 the @samp{des-cbc-md5} key from the kdc using the @kbd{kadmin
250 del_enctype} command.
253 kadmin del_enctype lha des-cbc-md5
256 You should also add the following entries to the @file{krb5.conf} file:
260 default_etypes = des-cbc-crc
261 default_etypes_des = des-cbc-crc
264 These configuration options will make sure that no checksums of the
265 unsupported types are generated.
267 @node Useful links when reading about the Windows, , Quirks of Windows 2000 KDC, Windows compatibility
268 @comment node-name, next, previous, up
269 @section Useful links when reading about the Windows
271 See also our paper presented at the 2001 Usenix Annual Technical
272 Conference, available in the proceedings or at
273 @uref{http://www.usenix.org/publications/library/proceedings/usenix01/freenix01/westerlund.html}.
275 There are lots of texts about Kerberos on Microsoft's web site, here is a
276 short list of the interesting documents that we have managed to find.
280 @item Step-by-Step Guide to Kerberos 5 (krb5 1.0) Interoperability:
281 @uref{http://www.microsoft.com/technet/prodtechnol/windows2000serv/howto/kerbstep.mspx}.
282 Kerberos GSS-API (in Windows-eze SSPI), Windows as a client in a
283 non-Windows KDC realm, adding unix clients to a Windows 2000 KDC, and
284 adding cross-realm trust (@pxref{Inter-Realm keys (trust) between Windows
287 @item Windows 2000 Kerberos Authentication:
288 @uref{www.microsoft.com/technet/prodtechnol/windows2000serv/deploy/confeat/kerberos.mspx}.
289 White paper that describes how Kerberos is used in Windows 2000.
291 @item Overview of Kerberos:
292 @uref{http://support.microsoft.com/support/kb/articles/Q248/7/58.ASP}.
293 Links to useful other links.
295 @c @item Klist for Windows:
296 @c @uref{http://msdn.microsoft.com/library/periodic/period00/security0500.htm}.
297 @c Describes where to get a klist for Windows 2000.
299 @item Event logging for Kerberos:
300 @uref{http://support.microsoft.com/support/kb/articles/Q262/1/77.ASP}.
301 Basically it say that you can add a registry key
302 @code{HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\Kerberos\Parameters\LogLevel}
303 with value DWORD equal to 1, and then you'll get logging in the Event
306 @c @item Access to the Active Directory through LDAP:
307 @c @uref{http://msdn.microsoft.com/library/techart/kerberossamp.htm}
311 Other useful programs include these:
315 @uref{http://www.bindview.com/Support/RAZOR/Utilities/Windows/pwdump2_readme.cfm}