1 h.sterling 1.1 <HTML>
2 <TITLE>OpenPegasus SSL Guidelines</TITLE>
3
4 <BODY>
5 <H2>OpenPegasus 2.5 SSL Guidelines</H2>
6
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7 h.sterling 1.2 <P><B>Version: </B>1.0<BR>
8 <B>Created: </B>July 20, 2005</P>
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9 h.sterling 1.1 <UL>
10 <LI><A HREF="#OVERVIEW">Overview</A>
11
12 <LI><A HREF="#RELATED">Related Information</A>
13 <LI><A HREF="#BUILDING">Building Pegasus with SSL</A>
14 <LI><A HREF="#CERTS">Creating SSL Certificates</A>
15 <LI><A HREF="#CONFIGURE">Configuring Pegasus for SSL</A>
16 <LI><A HREF="#DESIGN">SSL Design Question List</A>
17 <LI><A HREF="#TRUSTSTORE">Truststore Management</A>
18 <LI><A HREF="#CLI">ssltrustmgr CLI</A>
19 <LI><A HREF="#CLIENT">Configuring the Pegasus CIM Client for SSL</A>
20 <LI><A HREF="#AUTH">SSL Authorization</A>
21 <LI><A HREF="#RESOURCES">Resources</A>
22 </UL>
23
24
25 <H3><A NAME="OVERVIEW">Overview</A></H3>
26
27 <P>
28 The following document serves as a guide on how to build and configure Pegasus for SSL support. It also discusses how to utilize a certificate-based
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29 h.sterling 1.2 infrastructure and configure the Pegasus CIM client.
30 <P>
31 This guide requires a basic understanding of SSL, OpenSSL, and basic authentication. This guide is intended to help developers
32 and administrators make the right decisions about how to use SSL for their particular application.
33 It is not intended to be a primary source of education on SSL. If you are not familiar with these technologies,
34 consult the sources in the <A HREF="#RESOURCES">Resources</A> section at the bottom.
35 <P>
36
37 <P>Note:
38 In this document, the term "trust" refers only to authentication. It does not imply full trust in the traditional sense, because
39 it does not take into account authorization checks. It remains the responsibility of providers and clients to perform authorization,
40 and therefore establish real trust. Likewise, the term "Trust Store" can be misleading since the "store" is only a source of
41 authentication credentials. Please bear this in mind when documenting recommended deployments or building clients or providers.
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42 h.sterling 1.1 </P>
43
44 <H3><A NAME="RELATED">Related Information</A></H3>
45 A significant portion of the information in this document is taken from various PEP's.
46 This document attempts to bring all of this information
47 together in a cohesive and simplified format.
48 <P>
49 <UL>
50 <LI>PEP#035 - Add support for /dev/random in SSLContext</LI>
51 <LI>PEP#060 - SSL support in CIM/XML indication delivery</LI>
52 <LI>PEP#074 - SSLContext and Certificate verification interface enhancement</LI>
53 <LI>PEP#155 - Support for Client SSL Certificate Verification in CIM Server for CIMExport requests</LI>
54 <LI>PEP#165 - SSL Client Verification</LI>
55 <LI>PEP#187 - SSL Certificate Management Enhancements</LI>
56 <LI>PEP#200 - Recommended OpenPegasus 2.5 Build and Configuration Options for Selected Platforms</LI>
57 </UL>
58 </P>
59
60 <H3><A NAME="BUILDING">Building Pegasus with SSL</A></H3>
61
62 <P> To build Pegasus with HTTPS support, you will need to build against the <A HREF="http://www.openssl.org">OpenSSL
63 h.sterling 1.1 package</A>. The SSL support outlined here has been tested against recent releases of the major verions 0.9.6X and 0.9.7X (most notably, 0.9.7d).
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64 h.sterling 1.2 It has not been tested against major version 0.9.8, which came out in July 2005. Some tests have found that versions of 0.9.6X prior to 0.9.6c
65 do not contain the certificate revocation list (CRL) support that the OpenPegasus 2.5 utilizes.
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66 h.sterling 1.1 Because this is an open source project, the SSL support has been tested with many versions of OpenSSL,
67 but we cannot guarantee it has been tested with every version on every platform.
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68 h.sterling 1.2 A list of recent OpenSSL releases, and important-to-review security advisories and fixes, can
69 be found on the <A HREF="http://www.openssl.org/news">OpenSSL News page</A>.
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70 h.sterling 1.1 </P>
71 <P>
72 After grabbing the OpenSSL source tarball, you need to set the following environment variables before building Pegasus:
73 <UL>
74 <LI>PEGASUS_HAS_SSL=1</LI>
75 <LI>OPENSSL_HOME=<location of the SDK package> This directory must contain
76 the OpenSSL include directory, $(OPENSSL_HOME)/include, and the OpenSSL library
77 directory, $(OPENSSL_HOME)/lib.</LI>
78 <LI>OPENSSL_BIN=<location of the binary package> This only needs to be
79 set if the OpenSSL binaries are not in $(OPENSSL_HOME)/bin.</LI>
80 </UL>
81
82 Note that Pegasus supports SSLv3 and TLSv1 by default. It does NOT support SSLv2.
83 To turn on SSLv2 support, enable the additional environment variable:
84 <UL>
85 <LI> PEGASUS_ENABLE_SSLV2=1 </LI>
86 </UL>
87 <P>
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88 h.sterling 1.2 It is not recommended to enable this protocol, as there have been many security weaknesses associated with it. Unless you are dealing
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89 h.sterling 1.1 with very outdated clients, you probably do not need to enable it.
90 </P>
91 <P>
92 After setting these variables, proceed as normal with the build instructions in the readme file.
93 </P>
94
95 <H3><A NAME="CERTS">Creating SSL Certificates</A></H3>
96
97 There are two options for creating the CIMOM's certificate:
98 <UL>
99 <LI>Self-signed certificate</LI>
100 <LI>Certificate issued by a third-party certificate authority</LI>
101 </UL>
102 <P>
103 To generate a self-signed certificate, you must create a private key, a certificate signing request (CSR), and finally the public x509 certificate.
104 You also need an SSL configuration file that defines the parameters of the Distinguished Name (DN). You can use the one that comes with Pegasus,
105 ssl.cnf in the root directory, or generate your own. For a self-signed certificate, the subject
106 is the same as the issuer. Execute the following commands to create a self-signed certificate.
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107 h.sterling 1.2 The PEGASUS_ROOT and PEGASUS_HOME have to be set to your respective installation and source directory. You will also need an OpenSSL configuration
108 file. There is a sample configuration file that comes with the OpenSSL package.
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109 h.sterling 1.1
110 <P>
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111 h.sterling 1.2 <UL>
112 <LI>To generate a private key, execute the following:<BR>
113 <FONT FACE="courier" color="009900">openssl genrsa -out myserver.key 1024</FONT><BR>
114 Set the "sslKeyFilePath" configuration property to point to this key file.
115 </LI>
116 <LI>To generate a certificate signing request, execute the following:<BR>
117 <FONT FACE="courier" color="009900">openssl req -config openssl.cnf -new -key myserver.key -out myserver.csr</font>
118 </LI>
119 <LI> At this point, the certificate sigining request can be sent out to a third-party certificate authority for signing,
120 or a self-signed certificate can be generated. To generate a self-signed certificate, execute the following:<BR>
121 <FONT FACE="courier" color="009900">openssl x509 -in myserver.csr -out myserver.cert -req -signkey myserver.key -days 365</FONT><BR>
122 Set the "sslCertificateFilePath" configuration property to point to this certificate file. The above CSR file can be discarded
123 after the certificate is created.
124 </LI>
125 </UL>
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126 h.sterling 1.1
127 <P>
128 After creating the keypair, make sure you protect the information sufficiently by changing permissions on the files and/or directories.
129 The following table shows the recommended privileges:
130 <P>
131
132 <TABLE border="1" cellspacing="1" width="30%">
133 <TBODY>
134 <TR><TH><B>SSL file</B></TH><TH><B>Pegasus Config property</B></TH><TH><B>Permissions</B></TH></TR>
135 <TR><TD>Private key</td><TD>sslKeyFilePath</TD><TD>rwx------</TD></TR>
136 <TR><TD>Public certificate</td><TD>sslCertificateFilePath</TD> <TD>rwxr-xr-x</TD></TR>
137 <TR><TD>Truststore</td><TD>sslTrustStore, exportSSLTruststore</TD> <TD>rwxr-xr-x</TD></TR>
138 <TR><TD>CRL store </td><TD>crlStore</TD> <TD>rwxr-xr-x</TD></TR>
139 </TBODY>
140 </TABLE>
141 <P>
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142 h.sterling 1.2 The administrator is responsible for ensuring that the above file permissions are set correctly.
143 The administrator should also ensure that all containing directories all the way up to the base directory are not world-writeable. Pegasus only checks the following conditions when starting up:
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144 h.sterling 1.1 <UL>
145 <LI>The sslKeyFilePath and the sslCertificateFilePath are readable by the CIMOM.</LI>
146 <LI>The sslTrustStore, exportSSLTrustStore, and crlStore are readable by the CIMOM if they are a single file.</LI>
147 <LI>The sslTrustStore, exportSSLTrustStore, and crlStore are readable and writable by the CIMOM if they are a directory.</LI>
148 </UL>
149 <P>
150 These same file permissions should be used for protecting a client's private key, public key, truststore, and crl store as well.
151 <p>
152 For more information on generating keys and certificates, consult the <A HRef="http://www.openssl.org/docs/HOWTO/">OpenSSL
153 HOW-TO documentation</A>. </p>
154 <H3><A NAME="CONFIGURE">Configuring Pegasus for SSL</A></H3>
155
156 There are many environment variable settings associated with SSL. Here is a brief discussion of the subtleties of these options and how they work together to
157 create a more secure environment. More information on the default and recommended settings can be found in
158 PEP#200 Recommended OpenPegasus 2.5 Build and Configuration Options for Selected Platforms. Additionally, the section on
159 <A HREF="#DESIGN">Design Question List</A> should help determine what these settings should be for a given application.
160
161 <P>
162 <B>enableHttpsConnection</b><BR>
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163 h.sterling 1.2 This is disabled by default on most platforms. It is recommended that
164 all remote communication be done over the HTTPS port. However, if you are sending cleartext
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165 h.sterling 1.1 passwords over the wire, it is imperative that you only use the secure port.
166 For added security, the HTTP port can be disabled to prevent clients from connecting
167 to it.
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168 h.sterling 1.2 The HTTPS connection is enabled by default only on the following platforms:
169 <P>
170 <UL>
171 <LI>LINUX</LI>
172 <LI>OS-400</LI>
173 <LI>HP_UX (if PEGASUS_USE_RELEASE_CONFIG_OPTIONS is true)</LI>
174 <LI>VMS (if PEGASUS_USE_RELEASE_CONFIG_OPTIONS is true)</LI>
175 </UL>
176 </P>
177
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178 h.sterling 1.1 <P>
179 <B>httpsPort</B><BR>
180 The default setting is 5989, the official WBEM secure port.
181 <P> <B>sslCertificateFilePath</B> <BR>
182 This is the path to the x509 server certificate.
183 The server certificate may be a chain in which case the file should contain PEM encoded certificates beginning with the server certificate
184 and followed by each signing certificate authority (CA) including the root CA. If the server certificate is a self signed certificate,
185 the file only contains the self-signed certificate in PEM format.
186 The certificate cannot be encrypted because there is currently no mechanism for decrypting the certificate using a user-supplied password.
187 This property must be defined if enableHttpsConnection is true.
188 Any failure in finding this file will result in the cimserver failing to start.
189 See <A HREF="#CERTS">Creating SSL Certificates</A> for more information.
190 <P>
191 <B>sslKeyFilePath</B><BR>
192 This is the path to the server's private key. All keys should be at least 1024 bytes long. This property must be defined if
193 enableHttpsConnection is true. Any failure in finding this file will result in the cimserver failing to start.
194 See <A HREF="#CERTS">Creating SSL Certificate</A> for more information.
195 <P>
196 <B>sslClientVerificationMode</b><BR>
197 This setting controls how the cimserver (i.e. the HTTPS port) is configured.
198 It does not control the configuration of the export connection. There are three
199 h.sterling 1.1 possible settings: disabled, required, optional. There is no "right" setting
200 for this property. The default is disabled and it is fine to
201 leave the setting as disabled if you are going to use basic authentication to
202 authenticate all client requests. In many applications where a physical person
203 is there to supply a username and password, basic authentication is sufficient.
204 Other
205 environments may be heterogeneous, in which case it makes sense to allow both
206 basic authentication and SSL certificate verification. The setting of this variable
207 also impacts what happens during the OpenSSL handshake:
208 <UL>
209 <LI><B>"required"</B> -- The server requires that the client certificate be trusted in order for the handshake to continue.
210 If the client fails to send a certificate or sends an untrusted certificate, the handshake is immediately terminated.</LI>
211 <LI><B>"optional"</B> -- The server will request that a client certificate be sent, but will continue the handshake even if no certificate is
212 received. If authentication is enabled, the server will seek to authenticate the client via an alternative method of authentication.</LI>
213 <LI><B>"disabled"</B> -- The server will not prompt the client for a certificate. <I>This is the default.</I></LI>
214 </UL>
215 Pegasus currently ties a certificate to a valid OS user. Multiple certificates may be registered to the same user. When a certificate is
216 authenticated, Pegasus views it in the same way as if a user was authenticated via basic authentication. The providers
217 receive the username that the certificate was mapped to. See the SSL Authorization section
218 for more information.
219
220 h.sterling 1.1 <P>
221 <B>sslTrustStore</B><BR>
222 This setting controls the truststore for the cimserver's HTTPS connection. It can be
223 either a directory or a single root CA file. When set to a directory, it is recommended that you use the ssltrustmgr CLI
224 to populate the truststore as there are strict naming requirements for trusted certificate files. See the <A HREF="#CLI">ssltrustmgr CLI</A>
225 section for further information.
226 <P>
227 <B>sslTrustStoreUserName</B><BR>
228 This setting is only utilized if the sslTrustStore is a single CA file. It is not used if the sslTrustStore setting is a directory,
229 but it still must be set to a valid system user. This is because the validation of the property is done independently of the sslTrustStore
230 setting. This property represents the valid OS user that corresponds to the root certificate. All requests authenticated with a certificate
231 under the root CA will be associated with this user and the username will be propagated to providers. If applications desire for there to
232 be a one-to-one correspondence between users and certificates, it is recommended that each certificate be registered individually using the
233 <A HREF="#CLI">ssltrustmgr CLI</A>.
234 <P> <B>crlStore</B><BR>
235 This is where the CRL (Certificate Revocation List) store resides. There is
236 only one CRL store for all truststores. Currently, only two truststores are
237 supported (cimserver and export) and these both share the same CRL store. It
238 is important to note that certificates are checked first against the CRL (if
239 specified) and then against the truststore. The <A Href="#CLI">ssltrustmgr CLI</A>
240 should be used for CRL management.
241 h.sterling 1.1 <P>
242 <B>enableSSLExportClientVerification</B><BR>
243 This setting controls whether an ADDITIONAL port is used to listen for incoming indications. This port is used only as a CIM indication listener
244 and only supports HTTPS. The port number of the export connection is currently not configurable; the port is determined by looking
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245 h.sterling 1.2 in /etc/services for the service name wbem-exp-https.
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246 h.sterling 1.1 The export port is primarily used as a way to authenticate client indication requests. Because indications are generated by providers
247 and do not have a username/password associated with them, traditional basic authentication cannot be sent in the export request. To work
248 around this, a truststore can be configured to authenticate incoming requests. This truststore is configured like the "required"
249 setting of sslClientVerificationMode.
250 <P>
251 <B>exportSSLTrustStore</B><BR>
252 This setting controls the truststore for the export connection. It may be the same as the sslTrustStore. Additionally, it can be
253 either a directory or a single root CA file. When set to a directory, it is recommended that you use the <A HREF="#CLI">ssltrustmgr CLI</A>
254 to populate the truststore as there are strict naming requirements for trusted certificate files.
255
256 <H4>Configuration Limitations</H4>
257
258 The following are configuration limitations:
259
260 <UL>
261 <LI>The x509 server certificate file cannot be encrypted. The reason for this is that there is currently no mechanism in Pegasus to grab the
262 password needed to unencrypt it. Therefore, the best way to secure the file is to follow the file permissions settings specified in <A HREF="#CERTS">Creating SSL Certificates.</A></LI>
263 <LI>There is no property to specify supported cipher lists at this time. Pegasus uses the default OpenSSL cipher list. The cipher lists can be found at
264 <A HREF="http://www.openssl.org/docs/apps/ciphers.html#SSL_v3_0_cipher_suites_">http://www.openssl.org/docs/apps/ciphers.html#SSL_v3_0_cipher_suites_</A> and
265 <A HREF="http://www.openssl.org/docs/apps/ciphers.html#TLS_v1_0_cipher_suites_">http://www.openssl.org/docs/apps/ciphers.html#TLS_v1_0_cipher_suites_</A></LI>
266 <LI>The verification depth cannot be specified. Pegasus uses the default OpenSSL depth of 9. This means the OpenSSL will only accept client
267 h.sterling 1.1 certificate chains up to 9 levels deep.</LI>
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268 h.sterling 1.2 <LI>No hostname checking is performed to ensure that the subject field of the distinguished name (DN) matches the hostname.</LI>
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269 h.sterling 1.1 </UL>
270
271 <H3><A NAME="DESIGN">SSL Design Question List</A></H3>
272
273 <P>The following questions may be helpful in determining how to configure Pegasus CIM Server.</P>
274
275 <B>Should I enable the HTTPS port?</B><BR>
276 Yes, especially if you are sending passwords with requests. The HTTP port can be disabled for additional security if desired.
277 <BR>
278 <B>Should I enable the export port?</B><BR>
279 Currently, the export connection provides the only way to authenticate incoming CIM indication requests.
280 Because basic authentication cannot be used with these requests, the export connection should be enabled if
281 there is a concern over rogue client export requests. Otherwise, the export requests can still be sent over
282 HTTPS using the standard port; the information will be encrypted but the client's identity will not be validated.
283 <BR>
284 <B>Should I configure the CIMOM to use a truststore?</B><BR>
285 This depends on the infrastructure of the application. If all clients are using basic authentication over the secure port
286 (and the passwords are secured), then a truststore may not be needed. If an application does not want to store user/pw information,
287 then it is a good idea to use a certificate-based infrastructure. If a CIMOM certificate is compromised, the cimserver and the providers
288 of the system are compromised. The severity of this scenario is dependent on the resources the providers have access to.
289 If an OS password is compromised, the entire system may be compromised.
290 h.sterling 1.1 If using peer verification, it is important to ensure that 1) the cimserver is properly configured to use a truststore,
291 2) the truststore is loaded properly and protected, and 3) authorization checks are performed after a certificate is verified.
292 These same conditions also apply to a client that is verifying a server.<BR>
293
294 <B>Should I use a self-signed certificate or one issued by a third-party certificate authority?</B><BR>
295 Generally, scalability will determine whether it's appropriate to use a self-signed certificate or one issued by Verisign
296 or another third-party certificate authority.
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297 h.sterling 1.2 If an administrator administrates their self-signed certificates correctly, they are
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298 h.sterling 1.1 no less secure than one issued by a CA. What a CA buys you is scalability. An up front cost of
299 setting up a CA relationship will be offset by the convenience of having that
300 CA "vouch" for certs it has signed, in large deployments. In small deployments
301 the incremental cost might never outweigh the initial CA-setup cost. <BR>
302 One important thing to remember is that
303 you should not use the same certificate for multiple CIMOMs. If using a self-signed
304 certificate, a different one should be generated for each CIMOM, using some unique
305 piece of data to make them different. That way, if one of the certificates is
306 compromised, the other ones remain secure. <BR>
307 <B>Should the truststore be a single root CA file or a directory?</B><BR>
308 If you only anticipate connections from a narrowly defined set of clients, then a single root CA certificate file should be sufficient.
309 Alternatively, multiple trusted certificates may be stored in PEM format inside of a single CA file.
310 If you anticipate getting requests from a heterogeneous set of clients, then it probably makes sense to use the directory option
311 to allow flexibility in the future. In the latter scenario, the same single root CA file can still be used with the additional step of using ssltrustmgr to register it.
312 It's important to note that when registering a root CA, only one user can be associated with ALL certificates under that CA. Following the principle of
313 least privilege, it is not a good idea to register a root CA to a privileged user if lesser privileged users will be connecting with it.
314 <BR>
315 <B>How do I protect the keystore and the truststore?</B><BR>
316 The server's private key should always be protected; it is private for a reason.
317 Only the system administrator should be able to see it. The public certificate
318 can be viewed by anyone, however, it should be protected from alteration by system
319 h.sterling 1.1 users. Similarly, any truststore or CRL file or directory should also be protected
320 from alteration. See <A HREF="#CERTS">Creating SSL Certificates</A> for the recommended
321 file privileges. <BR>
322 <B>When do I need to use a CRL?</B><BR>
323 Certificate Revocation Lists are regularly issued by CA's. They contain a list
324 of certificates that have been revoked. Any application using a CA certificate
325 in its truststore should also implement CRLs (if the CA supports them). Pegasus itself
326 does not check CRL validity dates during startup. Therefore, it is the responsibility of the administrator
327 to regularly download or acquire the CRL and import it into the CRL store using the <A Href="#CLI">ssltrustmgr CLI</A>.
328 <BR>
329 If using self-signed certificates, however, a CRL is most likely not needed (You can create a self-signed CRL but it is not really
330 necessary). Because of this, the certificate deletion option available via ssltrusmgr is primarily intended for self-signed certificates.
331 Technically, CRL's are the correct way to revoke compromised or invalid certificates.
332 <BR>
333 <B>What is the order of operations for certificate verification?</B><BR>
334 The certificate is checked against any CRLs first before going through the rest of the verification process. Verification starts with the
335 root certificate and continues down to the peer certificate. If verification fails at any of these points, the certificate is considered
336 untrusted and the verification process reports an error.
337
338
339 <H3><A NAME="TRUSTSTORE">Truststore Management</A></H3>
340 h.sterling 1.1 There are two directions of trust in an SSL client-server handshake: The client trusts the server. The server trusts the client. Pegasus
341 provides a way to implement one or both of these relationships. Ideally, an application should support both levels of trust for maximum
342 security and this is the implementation Pegasus recommends. However, in some scenarios it may make sense to only implement one of these;
343 in that case, it is possible to override the client or the server to "trust all certificates." For example, if all clients will be using
344 basic authentication over HTTPS, then the server can be setup to "trust all client certificates."
345 <p> To tell the cimserver to require that all clients be trusted, simply set the
346 sslClientVerification property to "required."<BR>
347 To tell the cimserver to trust all clients, set the sslClientVerification property
348 to "disabled" or "optional".
349
350
351 <P>
352 The SSL verification in Pegasus is independent of any other authentication mechanism. It can still be utilized when authentication is disabled.
353 When authentication is enabled, the first line of defense is SSL client verification.
354 In situations where a client is not authenticated by SSL and the setting is "optional", the server will attempt to authenticate the client
355 via another method of authentication. In this case, the authentication mechanism specified by the configuration property "httpAuthType" will be used
356 for remote connections and local authentication will be used for local connections.
357
358 <P>
359 See the <A HREF="#CLIENT">Configuring the Pegasus CIM Client for SSL</A> section below on how to setup the client's truststore.
360
361 h.sterling 1.1 <H3><A NAME="CLI">ssltrustmgr CLI</A></H3>
362
363 Pegasus 2.5 comes with a new CLI, ssltrustmgr, that should be used to manage the cimserver's truststore, the export truststore, and the CRL store.
364 The CLI interfaces with a certificate control provider that runs as part of Pegasus's core. It operates on the PG_SSLCertificate and PG_SSLCertificateRevocationList
365 classes in root/pg_internal.
366 It is recommended that this CLI be used in place of manual configuration for several reasons:
367 <UL>
368 <LI>OpenSSL places strict naming restrictions on certificates and CRLs in a directory (the files are looked up via a subject hash code)</LI>
369 <LI>Certificate instances are stored in the repository along with the corresponding username. If the certificate is not properly registered,
370 the username mapping will fail.</LI>
371 <LI>The CLI allows for dynamic deletion of certificates by resetting the SSL context. Normally, you would need to stop and start
372 the cimserver to accomplish this.</LI>
373 <LI>The CLI, or more correctly the provider it operates on, performs a ton of error checking you would not get by manually configuring
374 the stores. This alerts the administrator to various error conditions (e.g. the certificate expired) associated with a certificate or CRL.</LI>
375 </UL>
376
377 The CIMOM must be up and running while executing ssltrustmgr. The ssltrustmgr manpage provides more information on commands and syntax.
378
379
380 <H3><A NAME="CLIENT">Configuring the Pegasus CIM Client for SSL</A></H3>
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381 h.sterling 1.2 <P> A Pegasus CIM client can be configured to use SSL by using a constructor that
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382 h.sterling 1.1 takes an SSLContext. The construction of the SSLContext is really what controls
383 the behavior of the client during the SSL handshake. Without going into minute
384 details about what happens under the covers, here is a description of the various
385 SSLContext constructor parameters. The descriptions are written from a client
386 perspective even though the same constructors are utilized by the cimserver
387 HTTPS port and export port.
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388 h.sterling 1.2
389 <P>
390 Here's a code snippet that shows how to call a client constructor that connects to a server over SSL and can present its own trusted certificate if
391 the server requests it. In this scenario, the client also checks the server certificate against its truststore and specifies an additional
392 callback in addition to the default one (the user-specified callback is optional and can be set to null).
393 <UL><FONT FACE="courier">
394 client.connect(
395 hostname,
396 port,
397 <B>SSLContext(trustStore, certPath, keyPath, verifyCert, randomFile),</B>
398 username,
399 password);
400 </FONT>
401 </UL>
402 </P>
403 <P>
404 Here's a code snippet that shows how to call a client constructor that connects to a server over SSL and does not possess its own trusted certificate.
405 In this scenario, the client also checks the server certificate against its truststore.
406 <UL>
407 <FONT FACE="courier">
408 client.connect(
409 h.sterling 1.2 hostname,
410 port,
411 <B>SSLContext(trustStore, NULL, randomFile),</B>
412 username
413 password);
414 </FONT>
415 </UL>
416 </P>
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417 h.sterling 1.1 <UL>
418 <LI><B>trustStore</B> -- This specifies the truststore that the client uses to verify server certificates. It can be String::EMPTY if no truststore exists. </LI>
419
420 <LI><B>certPath</B> -- This specifies the x509 certificate of the client that will be sent during an SSL handshake. Note that this certificate will
421 only be sent if the server requests it. If this option is specified, the keyPath parameter must also be specified.</LI>
422
423 <LI><B>keyPath</B> -- This specifies the private key of the client. If this option is specified, the certPath parameter must also be specified.</LI>
424
425 <LI><B>crlPath</B> -- This specifies an optional CRL store path. The client checks the CRL list first, before attempting any further authentication,
426 including the user-specified callback.</LI>
427
428 <LI><B>verifyCert</B> -- This is a user-specified verification callback. If this is set to null, the default OpenSSL verification callback will
429 be executed. You can implement this method to "trust all servers" or to perform additional authentication checks that OpenSSL does not perform
430 by default.</LI>
431
432 <LI><B>randomFile</B> -- A file to seed the pseudo random number generator (PRNG).</LI>
433
434 </UL>
435
436 <P>Here are some general guidelines on implementing peer verification for the client:
437 <UL>
438 h.sterling 1.1 <LI>The client should enable peer verification by specifying a truststore and (optionally) a user-specified callback function.</LI>
439 <LI>The client should employ a truststore in order to properly verify the server. The truststore should contain a file or directory of
440 trusted CA certificates. The ssltrustmgr CLI cannot be used to configure client truststores. The trusted certificate(s) should be placed
441 in a protected file or directory specified by the trustStore parameter. Keep in mind that the SSL context generally has to be reloaded
442 to pick up any truststore changes.</LI>
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443 h.sterling 1.2 <LI>The client could also use a user-specified callback in addition to the default verification callback, if additional verifications are desired over the normal checks that OpenSSL performs.
444 In most cases, the default verification callback is sufficient for checking server certificates.</LI>
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445 h.sterling 1.1 <LI>The client should ensure that adequate entropy is attained.</LI>
446 <LI>The client should use a CRL store if the truststore contains CA certificates that support one.</LI>
447 <LI>The client should only use the SSLv3 and TLSv1 protocols. By default, Pegasus is not built with SSLv2 support.</LI>
448
449 <li>The client should terform post-connection checks. </li>
450 <ul>
451 <li>Ensure a certificate was received.</li>
452 <ul>
453 <li>WARNING: In some implementations of SSL
454 a NULL server certificate is perfectly valid and authenticates against
455 all trust stores. If the client does not ensure a certificate
456 exists then the client is not providing server authentication and could
457 have a security bulletin class defect.</li>
458 </ul>
459 <li>Validate that the certificate received was issued to the
460 host for which the client was attempting to connect.</li>
461 <ul>
462 <li>Ensure that the common name (CN) in the server’s
463 certificate subject matches the host name of the server. For X509v3
464 certificates, the “<span class=SpellE>SubjectAltName</span>”
465 fields in the certificate's extended attributes are also valid host names
466 h.sterling 1.1 for the certificate. </li>
467 <li>WARNING: If the client does not ensure
468 the host name of the server is the same as one of the host names explicitly
469 described in the server’s certificate, you have not authenticated
470 the server’s identity. Any other server which was issued
471 a certificate from the same trusted CA can masquerade as the server
472 unless the client performs the host name check.</li>
473 </ul>
474 <li>Ensure that certificate verification methods/routines
475 return no errors.</li>
476 </ul>
477
478
479 </UL>
480
481 <P>
482 Because only the above arguments can be passed into the Pegasus SSLContext, there are some limitations in the client configuration:
483 <UL>
484 <LI>The verification depth cannot be specified. Pegasus uses the default OpenSSL depth of 9.</LI>
485 <LI>The cipher list cannot be specified. Pegasus uses the default OpenSSL cipher list. The cipher lists can be found at
486 <A HREF="http://www.openssl.org/docs/apps/ciphers.html#SSL_v3_0_cipher_suites_">http://www.openssl.org/docs/apps/ciphers.html#SSL_v3_0_cipher_suites_</A> and
487 h.sterling 1.1 <A HREF="http://www.openssl.org/docs/apps/ciphers.html#TLS_v1_0_cipher_suites_">http://www.openssl.org/docs/apps/ciphers.html#TLS_v1_0_cipher_suites_</A></LI>
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488 h.sterling 1.2 <LI>No hostname checking is performed to ensure that the subject field of the distinguished name (DN) matches the hostname. If desired, a user-specified callback should be configured
489 to perform this check or any additional checks relevant to the application.</LI>
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490 h.sterling 1.1 </UL>
491
492
493 <H3><A NAME="AUTH">SSL Authorization</A></H3>
494 <P>The following paragraphs concern authorization of users authenticated by certificate on the cimserver's HTTPS port.
495 <P> It is important to note that SSL certificates are verified during the initial
496 handshake, BEFORE any further authentication takes place. If a certificate fails,
497 the connection can be terminated immediately, resulting in a connection exception.
498 This scenario will occur if the sslClientVerification property is set to "required"
499 and no certificate or an untrusted certificate is sent. The export connection
500 will also terminate the connection if an untrusted certificate is presented.
501 Once a certificate is verified, no further <I><B>authentication</B></I> is attempted.
502 This effectively results in any basic or local authentication headers being
503 ignored.
504 <P>
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505 h.sterling 1.2 Further <I><B>authorization</B></I> checks must be performed when validating
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506 h.sterling 1.1 the user that is mapped to the certificate. First, the user that is registered to the certificate
507 is validated as a valid system user and a valid cimuser (if the cimuser function has been configured).
508 Additionally, if Pegasus was configured to use PAM, the pam_acct_mgmt function will be called with the
509 user that is mapped to the certificate. This ensures that any login conditions that would have been placed
510 on a user authenticated via basic authentication are still applied to a user authenticated via certificate.
511 The pam_authenticate method will NOT be called. Lastly, the providers must authorize the user. They receive the
512 username that was mapped to the certificate in the OperationContext.
513
514 <H3><A NAME="RESOURCES">Resources</A></H3>
515
516 <P>
517 For OpenSSL information pick up a copy of O'Reilly's Network Security with OpenSSL or go to the OpenSSL Site:<BR>
518 <A HREF="http://www.openssl.org">http://www.openssl.org</A>
519
520 <P>
521 A really fabulous guide on certificate management and installation with OpenSSL:<BR>
522 <A HREF="http://www.gagravarr.org/writing/openssl-certs/index.shtml">http://www.gagravarr.org/writing/openssl-certs/index.shtml</A>
523
524 <P>
525 x509 Certificate and CRL RFC:<BR>
526 <A HREF="http://www.ietf.org/rfc/rfc2459.txt?number=2459">http://www.ietf.org/rfc/rfc2459.txt?number=2459</A>
527 h.sterling 1.1
528 <P>
529 SSLv3 RFC:<BR>
530 <A HREF="http://wp.netscape.com/eng/ssl3/">http://wp.netscape.com/eng/ssl3</A>
531
532 <P>
533 TLSv1 RFC:<BR>
534 <A HREF="http://www.ietf.org/rfc/rfc2246.txt">http://www.ietf.org/rfc/rfc2246.txt</A>
535
536 <P>
537 Basic Authentication RFC:<BR>
538 <A HREF="http://www.faqs.org/rfcs/rfc2617.html">http://www.faqs.org/rfcs/rfc2617.html</A>
539
540 <hr>
541
542 <p><i><font size="2">Copyright (c) 2005 EMC Corporation; Hewlett-Packard Development
543
544 Company, L.P.; IBM Corp.; The Open Group; VERITAS Software Corporation</font><br>
545
546 <br>
547
548 h.sterling 1.1 <font size="1">Permission is hereby granted, free of charge, to any person
549
550 obtaining a copy of this software and associated documentation files (the
551
552 "Software"), to deal in the Software without restriction, including without
553
554 limitation the rights to use, copy, modify, merge, publish, distribute,
555
556 sublicense, and/or sell copies of the Software, and to permit persons to whom
557
558 the Software is furnished to do so, subject to the following conditions:</font><br>
559
560 <font size="2"><br>
561
562 </font>
563
564 <font size="1">THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN ALL
565
566 COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
567 "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
568
569 h.sterling 1.1 LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
570
571 AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
572
573 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
574
575 CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
576
577 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.</font></i></p>
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