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7 Copyright 2002-2005 The Apache Software Foundation or its licensors, as
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14 http://www.apache.org/licenses/LICENSE-2.0
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23 <modulesynopsis metafile="mod_ssl.xml.meta">
26 <description>Strong cryptography using the Secure Sockets
27 Layer (SSL) and Transport Layer Security (TLS) protocols</description>
28 <status>Extension</status>
29 <sourcefile>mod_ssl.c</sourcefile>
30 <identifier>ssl_module</identifier>
33 <p>This module provides SSL v2/v3 and TLS v1 support for the Apache
34 HTTP Server. It was contributed by Ralf S. Engeschall based on his
35 mod_ssl project and originally derived from work by Ben Laurie.</p>
37 <p>This module relies on <a href="http://www.openssl.org/">OpenSSL</a>
38 to provide the cryptography engine.</p>
40 <p>Further details, discussion, and examples are provided in the
41 <a href="../ssl/">SSL documentation</a>.</p>
44 <section id="envvars"><title>Environment Variables</title>
46 <p>This module provides a lot of SSL information as additional environment
47 variables to the SSI and CGI namespace. The generated variables are listed in
48 the table below. For backward compatibility the information can
49 be made available under different names, too. Look in the <a
50 href="../ssl/ssl_compat.html">Compatibility</a> chapter for details on the
51 compatibility variables.</p>
54 <columnspec><column width=".3"/><column width=".2"/><column width=".5"/>
57 <th><a name="table3">Variable Name:</a></th>
61 <tr><td><code>HTTPS</code></td> <td>flag</td> <td>HTTPS is being used.</td></tr>
62 <tr><td><code>SSL_PROTOCOL</code></td> <td>string</td> <td>The SSL protocol version (SSLv2, SSLv3, TLSv1)</td></tr>
63 <tr><td><code>SSL_SESSION_ID</code></td> <td>string</td> <td>The hex-encoded SSL session id</td></tr>
64 <tr><td><code>SSL_CIPHER</code></td> <td>string</td> <td>The cipher specification name</td></tr>
65 <tr><td><code>SSL_CIPHER_EXPORT</code></td> <td>string</td> <td><code>true</code> if cipher is an export cipher</td></tr>
66 <tr><td><code>SSL_CIPHER_USEKEYSIZE</code></td> <td>number</td> <td>Number of cipher bits (actually used)</td></tr>
67 <tr><td><code>SSL_CIPHER_ALGKEYSIZE</code></td> <td>number</td> <td>Number of cipher bits (possible)</td></tr>
68 <tr><td><code>SSL_COMPRESS_METHOD</code></td> <td>string</td> <td>SSL compression method negotiated</td></tr>
69 <tr><td><code>SSL_VERSION_INTERFACE</code></td> <td>string</td> <td>The mod_ssl program version</td></tr>
70 <tr><td><code>SSL_VERSION_LIBRARY</code></td> <td>string</td> <td>The OpenSSL program version</td></tr>
71 <tr><td><code>SSL_CLIENT_M_VERSION</code></td> <td>string</td> <td>The version of the client certificate</td></tr>
72 <tr><td><code>SSL_CLIENT_M_SERIAL</code></td> <td>string</td> <td>The serial of the client certificate</td></tr>
73 <tr><td><code>SSL_CLIENT_S_DN</code></td> <td>string</td> <td>Subject DN in client's certificate</td></tr>
74 <tr><td><code>SSL_CLIENT_S_DN_</code><em>x509</em></td> <td>string</td> <td>Component of client's Subject DN</td></tr>
75 <tr><td><code>SSL_CLIENT_I_DN</code></td> <td>string</td> <td>Issuer DN of client's certificate</td></tr>
76 <tr><td><code>SSL_CLIENT_I_DN_</code><em>x509</em></td> <td>string</td> <td>Component of client's Issuer DN</td></tr>
77 <tr><td><code>SSL_CLIENT_V_START</code></td> <td>string</td> <td>Validity of client's certificate (start time)</td></tr>
78 <tr><td><code>SSL_CLIENT_V_END</code></td> <td>string</td> <td>Validity of client's certificate (end time)</td></tr>
79 <tr><td><code>SSL_CLIENT_V_REMAIN</code></td> <td>string</td> <td>Number of days until client's certificate expires</td></tr>
80 <tr><td><code>SSL_CLIENT_A_SIG</code></td> <td>string</td> <td>Algorithm used for the signature of client's certificate</td></tr>
81 <tr><td><code>SSL_CLIENT_A_KEY</code></td> <td>string</td> <td>Algorithm used for the public key of client's certificate</td></tr>
82 <tr><td><code>SSL_CLIENT_CERT</code></td> <td>string</td> <td>PEM-encoded client certificate</td></tr>
83 <tr><td><code>SSL_CLIENT_CERT_CHAIN_</code><em>n</em></td> <td>string</td> <td>PEM-encoded certificates in client certificate chain</td></tr>
84 <tr><td><code>SSL_CLIENT_VERIFY</code></td> <td>string</td> <td><code>NONE</code>, <code>SUCCESS</code>, <code>GENEROUS</code> or <code>FAILED:</code><em>reason</em></td></tr>
85 <tr><td><code>SSL_SERVER_M_VERSION</code></td> <td>string</td> <td>The version of the server certificate</td></tr>
86 <tr><td><code>SSL_SERVER_M_SERIAL</code></td> <td>string</td> <td>The serial of the server certificate</td></tr>
87 <tr><td><code>SSL_SERVER_S_DN</code></td> <td>string</td> <td>Subject DN in server's certificate</td></tr>
88 <tr><td><code>SSL_SERVER_S_DN_</code><em>x509</em></td> <td>string</td> <td>Component of server's Subject DN</td></tr>
89 <tr><td><code>SSL_SERVER_I_DN</code></td> <td>string</td> <td>Issuer DN of server's certificate</td></tr>
90 <tr><td><code>SSL_SERVER_I_DN_</code><em>x509</em></td> <td>string</td> <td>Component of server's Issuer DN</td></tr>
91 <tr><td><code>SSL_SERVER_V_START</code></td> <td>string</td> <td>Validity of server's certificate (start time)</td></tr>
92 <tr><td><code>SSL_SERVER_V_END</code></td> <td>string</td> <td>Validity of server's certificate (end time)</td></tr>
93 <tr><td><code>SSL_SERVER_A_SIG</code></td> <td>string</td> <td>Algorithm used for the signature of server's certificate</td></tr>
94 <tr><td><code>SSL_SERVER_A_KEY</code></td> <td>string</td> <td>Algorithm used for the public key of server's certificate</td></tr>
95 <tr><td><code>SSL_SERVER_CERT</code></td> <td>string</td> <td>PEM-encoded server certificate</td></tr>
98 <p><em>x509</em> specifies a component of an X.509 DN; one of
99 <code>C,ST,L,O,OU,CN,T,I,G,S,D,UID,Email</code>. In Apache 2.1 and
100 later, <em>x509</em> may also include a numeric <code>_n</code>
101 suffix. If the DN in question contains multiple attributes of the
102 same name, this suffix is used as an index to select a particular
103 attribute. For example, where the server certificate subject DN
104 included two OU fields, <code>SSL_SERVER_S_DN_OU_0</code> and
105 <code>SSL_SERVER_S_DN_OU_1</code> could be used to reference each.</p>
107 <p><code>SSL_CLIENT_V_REMAIN</code> is only available in version 2.1
112 <section id="logformats"><title>Custom Log Formats</title>
114 <p>When <module>mod_ssl</module> is built into Apache or at least
115 loaded (under DSO situation) additional functions exist for the <a
116 href="mod_log_config.html#formats">Custom Log Format</a> of
117 <module>mod_log_config</module>. First there is an
118 additional ``<code>%{</code><em>varname</em><code>}x</code>''
119 eXtension format function which can be used to expand any variables
120 provided by any module, especially those provided by mod_ssl which can
121 you find in the above table.</p>
123 For backward compatibility there is additionally a special
124 ``<code>%{</code><em>name</em><code>}c</code>'' cryptography format function
125 provided. Information about this function is provided in the <a
126 href="../ssl/ssl_compat.html">Compatibility</a> chapter.</p>
127 <example><title>Example</title>
128 CustomLog logs/ssl_request_log \
129 "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"
134 <name>SSLPassPhraseDialog</name>
135 <description>Type of pass phrase dialog for encrypted private
137 <syntax>SSLPassPhraseDialog <em>type</em></syntax>
138 <default>SSLPassPhraseDialog builtin</default>
139 <contextlist><context>server config</context></contextlist>
143 When Apache starts up it has to read the various Certificate (see
144 <directive module="mod_ssl">SSLCertificateFile</directive>) and
145 Private Key (see <directive
146 module="mod_ssl">SSLCertificateKeyFile</directive>) files of the
147 SSL-enabled virtual servers. Because for security reasons the Private
148 Key files are usually encrypted, mod_ssl needs to query the
149 administrator for a Pass Phrase in order to decrypt those files. This
150 query can be done in two ways which can be configured by
153 <li><code>builtin</code>
155 This is the default where an interactive terminal dialog occurs at startup
156 time just before Apache detaches from the terminal. Here the administrator
157 has to manually enter the Pass Phrase for each encrypted Private Key file.
158 Because a lot of SSL-enabled virtual hosts can be configured, the
159 following reuse-scheme is used to minimize the dialog: When a Private Key
160 file is encrypted, all known Pass Phrases (at the beginning there are
161 none, of course) are tried. If one of those known Pass Phrases succeeds no
162 dialog pops up for this particular Private Key file. If none succeeded,
163 another Pass Phrase is queried on the terminal and remembered for the next
164 round (where it perhaps can be reused).</p>
166 This scheme allows mod_ssl to be maximally flexible (because for N encrypted
167 Private Key files you <em>can</em> use N different Pass Phrases - but then
168 you have to enter all of them, of course) while minimizing the terminal
169 dialog (i.e. when you use a single Pass Phrase for all N Private Key files
170 this Pass Phrase is queried only once).</p></li>
172 <li><code>|/path/to/program [args...]</code>
174 <p>This mode allows an external program to be used which acts as a
175 pipe to a particular input device; the program is sent the standard
176 prompt text used for the <code>builtin</code> mode on
177 <code>stdin</code>, and is expected to write password strings on
178 <code>stdout</code>. If several passwords are needed (or an
179 incorrect password is entered), additional prompt text will be
180 written subsequent to the first password being returned, and more
181 passwords must then be written back.</p></li>
183 <li><code>exec:/path/to/program</code>
185 Here an external program is configured which is called at startup for each
186 encrypted Private Key file. It is called with two arguments (the first is
187 of the form ``<code>servername:portnumber</code>'', the second is either
188 ``<code>RSA</code>'' or ``<code>DSA</code>''), which indicate for which
189 server and algorithm it has to print the corresponding Pass Phrase to
190 <code>stdout</code>. The intent is that this external program first runs
191 security checks to make sure that the system is not compromised by an
192 attacker, and only when these checks were passed successfully it provides
195 Both these security checks, and the way the Pass Phrase is determined, can
196 be as complex as you like. Mod_ssl just defines the interface: an
197 executable program which provides the Pass Phrase on <code>stdout</code>.
198 Nothing more or less! So, if you're really paranoid about security, here
199 is your interface. Anything else has to be left as an exercise to the
200 administrator, because local security requirements are so different.</p>
202 The reuse-algorithm above is used here, too. In other words: The external
203 program is called only once per unique Pass Phrase.</p></li>
205 <example><title>Example</title>
206 SSLPassPhraseDialog exec:/usr/local/apache/sbin/pp-filter
212 <name>SSLMutex</name>
213 <description>Semaphore for internal mutual exclusion of
214 operations</description>
215 <syntax>SSLMutex <em>type</em></syntax>
216 <default>SSLMutex none</default>
217 <contextlist><context>server config</context></contextlist>
221 This configures the SSL engine's semaphore (aka. lock) which is used for mutual
222 exclusion of operations which have to be done in a synchronized way between the
223 pre-forked Apache server processes. This directive can only be used in the
224 global server context because it's only useful to have one global mutex.
225 This directive is designed to closely match the
226 <directive module="mpm_common">AcceptMutex</directive> directive.</p>
228 The following Mutex <em>types</em> are available:</p>
230 <li><code>none | no</code>
232 This is the default where no Mutex is used at all. Use it at your own
233 risk. But because currently the Mutex is mainly used for synchronizing
234 write access to the SSL Session Cache you can live without it as long
235 as you accept a sometimes garbled Session Cache. So it's not recommended
236 to leave this the default. Instead configure a real Mutex.</p></li>
237 <li><code>posixsem</code>
239 This is an elegant Mutex variant where a Posix Semaphore is used when possible.
240 It is only available when the underlying platform
241 and <glossary>APR</glossary> supports it.</p></li>
242 <li><code>sysvsem</code>
244 This is a somewhat elegant Mutex variant where a SystemV IPC Semaphore is used when
245 possible. It is possible to "leak" SysV semaphores if processes crash before
246 the semaphore is removed. It is only available when the underlying platform
247 and <glossary>APR</glossary> supports it.</p></li>
250 This directive tells the SSL Module to pick the "best" semaphore implementation
251 available to it, choosing between Posix and SystemV IPC, in that order. It is only
252 available when the underlying platform and <glossary>APR</glossary> supports at least one of the 2.</p></li>
253 <li><code>pthread</code>
255 This directive tells the SSL Module to use Posix thread mutexes. It is only available
256 if the underlying platform and <glossary>APR</glossary> supports it.</p></li>
257 <li><code>fcntl:/path/to/mutex</code>
259 This is a portable Mutex variant where a physical (lock-)file and the <code>fcntl()</code>
260 fucntion are used as the Mutex.
261 Always use a local disk filesystem for <code>/path/to/mutex</code> and never a file
262 residing on a NFS- or AFS-filesystem. It is only available when the underlying platform
263 and <glossary>APR</glossary> supports it. Note: Internally, the Process ID (PID) of the
264 Apache parent process is automatically appended to
265 <code>/path/to/mutex</code> to make it unique, so you don't have to worry
266 about conflicts yourself. Notice that this type of mutex is not available
267 under the Win32 environment. There you <em>have</em> to use the semaphore
269 <li><code>flock:/path/to/mutex</code>
271 This is similar to the <code>fcntl:/path/to/mutex</code> method with the
272 exception that the <code>flock()</code> function is used to provide file
273 locking. It is only available when the underlying platform
274 and <glossary>APR</glossary> supports it.</p></li>
275 <li><code>file:/path/to/mutex</code>
277 This directive tells the SSL Module to pick the "best" file locking implementation
278 available to it, choosing between <code>fcntl</code> and <code>flock</code>,
279 in that order. It is only available when the underlying platform and <glossary>APR</glossary> supports
280 at least one of the 2.</p></li>
281 <li><code>default | yes</code>
283 This directive tells the SSL Module to pick the default locking implementation
284 as determined by the platform and <glossary>APR</glossary>.</p></li>
286 <example><title>Example</title>
287 SSLMutex file:/usr/local/apache/logs/ssl_mutex
293 <name>SSLRandomSeed</name>
294 <description>Pseudo Random Number Generator (PRNG) seeding
296 <syntax>SSLRandomSeed <em>context</em> <em>source</em>
297 [<em>bytes</em>]</syntax>
298 <contextlist><context>server config</context></contextlist>
302 This configures one or more sources for seeding the Pseudo Random Number
303 Generator (PRNG) in OpenSSL at startup time (<em>context</em> is
304 <code>startup</code>) and/or just before a new SSL connection is established
305 (<em>context</em> is <code>connect</code>). This directive can only be used
306 in the global server context because the PRNG is a global facility.</p>
308 The following <em>source</em> variants are available:</p>
310 <li><code>builtin</code>
311 <p> This is the always available builtin seeding source. It's usage
312 consumes minimum CPU cycles under runtime and hence can be always used
313 without drawbacks. The source used for seeding the PRNG contains of the
314 current time, the current process id and (when applicable) a randomly
315 choosen 1KB extract of the inter-process scoreboard structure of Apache.
316 The drawback is that this is not really a strong source and at startup
317 time (where the scoreboard is still not available) this source just
318 produces a few bytes of entropy. So you should always, at least for the
319 startup, use an additional seeding source.</p></li>
320 <li><code>file:/path/to/source</code>
322 This variant uses an external file <code>/path/to/source</code> as the
323 source for seeding the PRNG. When <em>bytes</em> is specified, only the
324 first <em>bytes</em> number of bytes of the file form the entropy (and
325 <em>bytes</em> is given to <code>/path/to/source</code> as the first
326 argument). When <em>bytes</em> is not specified the whole file forms the
327 entropy (and <code>0</code> is given to <code>/path/to/source</code> as
328 the first argument). Use this especially at startup time, for instance
329 with an available <code>/dev/random</code> and/or
330 <code>/dev/urandom</code> devices (which usually exist on modern Unix
331 derivates like FreeBSD and Linux).</p>
333 <em>But be careful</em>: Usually <code>/dev/random</code> provides only as
334 much entropy data as it actually has, i.e. when you request 512 bytes of
335 entropy, but the device currently has only 100 bytes available two things
336 can happen: On some platforms you receive only the 100 bytes while on
337 other platforms the read blocks until enough bytes are available (which
338 can take a long time). Here using an existing <code>/dev/urandom</code> is
339 better, because it never blocks and actually gives the amount of requested
340 data. The drawback is just that the quality of the received data may not
343 On some platforms like FreeBSD one can even control how the entropy is
344 actually generated, i.e. by which system interrupts. More details one can
345 find under <em>rndcontrol(8)</em> on those platforms. Alternatively, when
346 your system lacks such a random device, you can use tool
347 like <a href="http://www.lothar.com/tech/crypto/">EGD</a>
348 (Entropy Gathering Daemon) and run it's client program with the
349 <code>exec:/path/to/program/</code> variant (see below) or use
350 <code>egd:/path/to/egd-socket</code> (see below).</p></li>
352 <li><code>exec:/path/to/program</code>
354 This variant uses an external executable
355 <code>/path/to/program</code> as the source for seeding the
356 PRNG. When <em>bytes</em> is specified, only the first
357 <em>bytes</em> number of bytes of its <code>stdout</code> contents
358 form the entropy. When <em>bytes</em> is not specified, the
359 entirety of the data produced on <code>stdout</code> form the
360 entropy. Use this only at startup time when you need a very strong
361 seeding with the help of an external program (for instance as in
362 the example above with the <code>truerand</code> utility you can
363 find in the mod_ssl distribution which is based on the AT&T
364 <em>truerand</em> library). Using this in the connection context
365 slows down the server too dramatically, of course. So usually you
366 should avoid using external programs in that context.</p></li>
367 <li><code>egd:/path/to/egd-socket</code> (Unix only)
369 This variant uses the Unix domain socket of the
370 external Entropy Gathering Daemon (EGD) (see <a
371 href="http://www.lothar.com/tech/crypto/">http://www.lothar.com/tech
372 /crypto/</a>) to seed the PRNG. Use this if no random device exists
373 on your platform.</p></li>
375 <example><title>Example</title>
376 SSLRandomSeed startup builtin<br />
377 SSLRandomSeed startup file:/dev/random<br />
378 SSLRandomSeed startup file:/dev/urandom 1024<br />
379 SSLRandomSeed startup exec:/usr/local/bin/truerand 16<br />
380 SSLRandomSeed connect builtin<br />
381 SSLRandomSeed connect file:/dev/random<br />
382 SSLRandomSeed connect file:/dev/urandom 1024<br />
388 <name>SSLSessionCache</name>
389 <description>Type of the global/inter-process SSL Session
391 <syntax>SSLSessionCache <em>type</em></syntax>
392 <default>SSLSessionCache none</default>
393 <contextlist><context>server config</context></contextlist>
397 This configures the storage type of the global/inter-process SSL Session
398 Cache. This cache is an optional facility which speeds up parallel request
399 processing. For requests to the same server process (via HTTP keep-alive),
400 OpenSSL already caches the SSL session information locally. But because modern
401 clients request inlined images and other data via parallel requests (usually
402 up to four parallel requests are common) those requests are served by
403 <em>different</em> pre-forked server processes. Here an inter-process cache
404 helps to avoid unneccessary session handshakes.</p>
406 The following four storage <em>type</em>s are currently supported:</p>
408 <li><code>none</code>
410 <p>This disables the global/inter-process Session Cache. This
411 will incur a noticeable speed penalty and may cause problems if
412 using certain browsers, particularly if client certificates are
413 enabled. This setting is not recommended.</p></li>
415 <li><code>nonenotnull</code>
417 <p>This disables any global/inter-process Session Cache. However
418 it does force OpenSSL to send a non-null session ID to
419 accommodate buggy clients that require one.</p></li>
421 <li><code>dbm:/path/to/datafile</code>
423 <p>This makes use of a DBM hashfile on the local disk to
424 synchronize the local OpenSSL memory caches of the server
425 processes. This session cache may suffer reliability issues under
428 <li><code>shm:/path/to/datafile</code>[<code>(</code><em>size</em><code>)</code>]
430 <p>This makes use of a high-performance cyclic buffer
431 (approx. <em>size</em> bytes in size) inside a shared memory
432 segment in RAM (established via <code>/path/to/datafile</code>) to
433 synchronize the local OpenSSL memory caches of the server
434 processes. This is the recommended session cache.</p></li>
436 <li><code>dc:UNIX:/path/to/socket</code>
438 <p>This makes use of the <a
439 href="http://www.distcache.org/">distcache</a> distributed session
440 caching libraries. The argument should specify the location of
441 the server or proxy to be used using the distcache address syntax;
442 for example, <code>UNIX:/path/to/socket</code> specifies a UNIX
443 domain socket (typically a local dc_client proxy);
444 <code>IP:server.example.com:9001</code> specifies an IP
448 <example><title>Examples</title>
449 SSLSessionCache dbm:/usr/local/apache/logs/ssl_gcache_data<br />
450 SSLSessionCache shm:/usr/local/apache/logs/ssl_gcache_data(512000)
456 <name>SSLSessionCacheTimeout</name>
457 <description>Number of seconds before an SSL session expires
458 in the Session Cache</description>
459 <syntax>SSLSessionCacheTimeout <em>seconds</em></syntax>
460 <default>SSLSessionCacheTimeout 300</default>
461 <contextlist><context>server config</context>
462 <context>virtual host</context></contextlist>
466 This directive sets the timeout in seconds for the information stored in the
467 global/inter-process SSL Session Cache and the OpenSSL internal memory cache.
468 It can be set as low as 15 for testing, but should be set to higher
469 values like 300 in real life.</p>
470 <example><title>Example</title>
471 SSLSessionCacheTimeout 600
477 <name>SSLEngine</name>
478 <description>SSL Engine Operation Switch</description>
479 <syntax>SSLEngine on|off|optional</syntax>
480 <default>SSLEngine off</default>
481 <contextlist><context>server config</context>
482 <context>virtual host</context></contextlist>
486 This directive toggles the usage of the SSL/TLS Protocol Engine. This
487 is usually used inside a <directive module="core"
488 type="section">VirtualHost</directive> section to enable SSL/TLS for a
489 particular virtual host. By default the SSL/TLS Protocol Engine is
490 disabled for both the main server and all configured virtual hosts.</p>
491 <example><title>Example</title>
492 <VirtualHost _default_:443><br />
497 <p>In Apache 2.1 and later, <directive>SSLEngine</directive> can be set to
498 <code>optional</code>. This enables support for
499 <a href="http://www.ietf.org/rfc/rfc2817.txt">RFC 2817</a>, Upgrading to TLS
500 Within HTTP/1.1. At this time no web browsers support RFC 2817.</p>
505 <name>SSLProtocol</name>
506 <description>Configure usable SSL protocol flavors</description>
507 <syntax>SSLProtocol [+|-]<em>protocol</em> ...</syntax>
508 <default>SSLProtocol all</default>
509 <contextlist><context>server config</context>
510 <context>virtual host</context></contextlist>
511 <override>Options</override>
513 <usage><!-- XXX Why does this have an override and not .htaccess context? -->
515 This directive can be used to control the SSL protocol flavors mod_ssl should
516 use when establishing its server environment. Clients then can only connect
517 with one of the provided protocols.</p>
519 The available (case-insensitive) <em>protocol</em>s are:</p>
521 <li><code>SSLv2</code>
523 This is the Secure Sockets Layer (SSL) protocol, version 2.0. It is the
524 original SSL protocol as designed by Netscape Corporation.</p></li>
526 <li><code>SSLv3</code>
528 This is the Secure Sockets Layer (SSL) protocol, version 3.0. It is the
529 successor to SSLv2 and the currently (as of February 1999) de-facto
530 standardized SSL protocol from Netscape Corporation. It's supported by
531 almost all popular browsers.</p></li>
533 <li><code>TLSv1</code>
535 This is the Transport Layer Security (TLS) protocol, version 1.0. It is the
536 successor to SSLv3 and currently (as of February 1999) still under
537 construction by the Internet Engineering Task Force (IETF). It's still
538 not supported by any popular browsers.</p></li>
542 This is a shortcut for ``<code>+SSLv2 +SSLv3 +TLSv1</code>'' and a
543 convinient way for enabling all protocols except one when used in
544 combination with the minus sign on a protocol as the example above
547 <example><title>Example</title>
548 # enable SSLv3 and TLSv1, but not SSLv2<br />
549 SSLProtocol all -SSLv2
555 <name>SSLCipherSuite</name>
556 <description>Cipher Suite available for negotiation in SSL
557 handshake</description>
558 <syntax>SSLCipherSuite <em>cipher-spec</em></syntax>
559 <default>SSLCipherSuite ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP</default>
560 <contextlist><context>server config</context>
561 <context>virtual host</context>
562 <context>directory</context>
563 <context>.htaccess</context></contextlist>
564 <override>AuthConfig</override>
568 This complex directive uses a colon-separated <em>cipher-spec</em> string
569 consisting of OpenSSL cipher specifications to configure the Cipher Suite the
570 client is permitted to negotiate in the SSL handshake phase. Notice that this
571 directive can be used both in per-server and per-directory context. In
572 per-server context it applies to the standard SSL handshake when a connection
573 is established. In per-directory context it forces a SSL renegotation with the
574 reconfigured Cipher Suite after the HTTP request was read but before the HTTP
575 response is sent.</p>
577 An SSL cipher specification in <em>cipher-spec</em> is composed of 4 major
578 attributes plus a few extra minor ones:</p>
580 <li><em>Key Exchange Algorithm</em>:<br />
581 RSA or Diffie-Hellman variants.
583 <li><em>Authentication Algorithm</em>:<br />
584 RSA, Diffie-Hellman, DSS or none.
586 <li><em>Cipher/Encryption Algorithm</em>:<br />
587 DES, Triple-DES, RC4, RC2, IDEA or none.
589 <li><em>MAC Digest Algorithm</em>:<br />
593 <p>An SSL cipher can also be an export cipher and is either a SSLv2 or SSLv3/TLSv1
594 cipher (here TLSv1 is equivalent to SSLv3). To specify which ciphers to use,
595 one can either specify all the Ciphers, one at a time, or use aliases to
596 specify the preference and order for the ciphers (see <a href="#table1">Table
600 <columnspec><column width=".5"/><column width=".5"/></columnspec>
601 <tr><th><a name="table1">Tag</a></th> <th>Description</th></tr>
602 <tr><td colspan="2"><em>Key Exchange Algorithm:</em></td></tr>
603 <tr><td><code>kRSA</code></td> <td>RSA key exchange</td></tr>
604 <tr><td><code>kDHr</code></td> <td>Diffie-Hellman key exchange with RSA key</td></tr>
605 <tr><td><code>kDHd</code></td> <td>Diffie-Hellman key exchange with DSA key</td></tr>
606 <tr><td><code>kEDH</code></td> <td>Ephemeral (temp.key) Diffie-Hellman key exchange (no cert)</td> </tr>
607 <tr><td colspan="2"><em>Authentication Algorithm:</em></td></tr>
608 <tr><td><code>aNULL</code></td> <td>No authentication</td></tr>
609 <tr><td><code>aRSA</code></td> <td>RSA authentication</td></tr>
610 <tr><td><code>aDSS</code></td> <td>DSS authentication</td> </tr>
611 <tr><td><code>aDH</code></td> <td>Diffie-Hellman authentication</td></tr>
612 <tr><td colspan="2"><em>Cipher Encoding Algorithm:</em></td></tr>
613 <tr><td><code>eNULL</code></td> <td>No encoding</td> </tr>
614 <tr><td><code>DES</code></td> <td>DES encoding</td> </tr>
615 <tr><td><code>3DES</code></td> <td>Triple-DES encoding</td> </tr>
616 <tr><td><code>RC4</code></td> <td>RC4 encoding</td> </tr>
617 <tr><td><code>RC2</code></td> <td>RC2 encoding</td> </tr>
618 <tr><td><code>IDEA</code></td> <td>IDEA encoding</td> </tr>
619 <tr><td colspan="2"><em>MAC Digest Algorithm</em>:</td></tr>
620 <tr><td><code>MD5</code></td> <td>MD5 hash function</td></tr>
621 <tr><td><code>SHA1</code></td> <td>SHA1 hash function</td></tr>
622 <tr><td><code>SHA</code></td> <td>SHA hash function</td> </tr>
623 <tr><td colspan="2"><em>Aliases:</em></td></tr>
624 <tr><td><code>SSLv2</code></td> <td>all SSL version 2.0 ciphers</td></tr>
625 <tr><td><code>SSLv3</code></td> <td>all SSL version 3.0 ciphers</td> </tr>
626 <tr><td><code>TLSv1</code></td> <td>all TLS version 1.0 ciphers</td> </tr>
627 <tr><td><code>EXP</code></td> <td>all export ciphers</td> </tr>
628 <tr><td><code>EXPORT40</code></td> <td>all 40-bit export ciphers only</td> </tr>
629 <tr><td><code>EXPORT56</code></td> <td>all 56-bit export ciphers only</td> </tr>
630 <tr><td><code>LOW</code></td> <td>all low strength ciphers (no export, single DES)</td></tr>
631 <tr><td><code>MEDIUM</code></td> <td>all ciphers with 128 bit encryption</td> </tr>
632 <tr><td><code>HIGH</code></td> <td>all ciphers using Triple-DES</td> </tr>
633 <tr><td><code>RSA</code></td> <td>all ciphers using RSA key exchange</td> </tr>
634 <tr><td><code>DH</code></td> <td>all ciphers using Diffie-Hellman key exchange</td> </tr>
635 <tr><td><code>EDH</code></td> <td>all ciphers using Ephemeral Diffie-Hellman key exchange</td> </tr>
636 <tr><td><code>ADH</code></td> <td>all ciphers using Anonymous Diffie-Hellman key exchange</td> </tr>
637 <tr><td><code>DSS</code></td> <td>all ciphers using DSS authentication</td> </tr>
638 <tr><td><code>NULL</code></td> <td>all ciphers using no encryption</td> </tr>
641 Now where this becomes interesting is that these can be put together
642 to specify the order and ciphers you wish to use. To speed this up
643 there are also aliases (<code>SSLv2, SSLv3, TLSv1, EXP, LOW, MEDIUM,
644 HIGH</code>) for certain groups of ciphers. These tags can be joined
645 together with prefixes to form the <em>cipher-spec</em>. Available
648 <li>none: add cipher to list</li>
649 <li><code>+</code>: add ciphers to list and pull them to current location in list</li>
650 <li><code>-</code>: remove cipher from list (can be added later again)</li>
651 <li><code>!</code>: kill cipher from list completely (can <strong>not</strong> be added later again)</li>
653 <p>A simpler way to look at all of this is to use the ``<code>openssl ciphers
654 -v</code>'' command which provides a nice way to successively create the
655 correct <em>cipher-spec</em> string. The default <em>cipher-spec</em> string
656 is ``<code>ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP</code>'' which
657 means the following: first, remove from consideration any ciphers that do not
658 authenticate, i.e. for SSL only the Anonymous Diffie-Hellman ciphers. Next,
659 use ciphers using RC4 and RSA. Next include the high, medium and then the low
660 security ciphers. Finally <em>pull</em> all SSLv2 and export ciphers to the
664 $ openssl ciphers -v 'ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP'
665 NULL-SHA SSLv3 Kx=RSA Au=RSA Enc=None Mac=SHA1
666 NULL-MD5 SSLv3 Kx=RSA Au=RSA Enc=None Mac=MD5
667 EDH-RSA-DES-CBC3-SHA SSLv3 Kx=DH Au=RSA Enc=3DES(168) Mac=SHA1
669 EXP-RC4-MD5 SSLv3 Kx=RSA(512) Au=RSA Enc=RC4(40) Mac=MD5 export
670 EXP-RC2-CBC-MD5 SSLv2 Kx=RSA(512) Au=RSA Enc=RC2(40) Mac=MD5 export
671 EXP-RC4-MD5 SSLv2 Kx=RSA(512) Au=RSA Enc=RC4(40) Mac=MD5 export
674 <p>The complete list of particular RSA & DH ciphers for SSL is given in <a
675 href="#table2">Table 2</a>.</p>
676 <example><title>Example</title>
677 SSLCipherSuite RSA:!EXP:!NULL:+HIGH:+MEDIUM:-LOW
680 <columnspec><column width=".3"/><column width=".1"/><column width=".13"/>
681 <column width=".1"/><column width=".13"/><column width=".1"/>
682 <column width=".13"/></columnspec>
683 <tr><th><a name="table2">Cipher-Tag</a></th> <th>Protocol</th> <th>Key Ex.</th> <th>Auth.</th> <th>Enc.</th> <th>MAC</th> <th>Type</th> </tr>
684 <tr><td colspan="7"><em>RSA Ciphers:</em></td></tr>
685 <tr><td><code>DES-CBC3-SHA</code></td> <td>SSLv3</td> <td>RSA</td> <td>RSA</td> <td>3DES(168)</td> <td>SHA1</td> <td></td> </tr>
686 <tr><td><code>DES-CBC3-MD5</code></td> <td>SSLv2</td> <td>RSA</td> <td>RSA</td> <td>3DES(168)</td> <td>MD5</td> <td></td> </tr>
687 <tr><td><code>IDEA-CBC-SHA</code></td> <td>SSLv3</td> <td>RSA</td> <td>RSA</td> <td>IDEA(128)</td> <td>SHA1</td> <td></td> </tr>
688 <tr><td><code>RC4-SHA</code></td> <td>SSLv3</td> <td>RSA</td> <td>RSA</td> <td>RC4(128)</td> <td>SHA1</td> <td></td> </tr>
689 <tr><td><code>RC4-MD5</code></td> <td>SSLv3</td> <td>RSA</td> <td>RSA</td> <td>RC4(128)</td> <td>MD5</td> <td></td> </tr>
690 <tr><td><code>IDEA-CBC-MD5</code></td> <td>SSLv2</td> <td>RSA</td> <td>RSA</td> <td>IDEA(128)</td> <td>MD5</td> <td></td> </tr>
691 <tr><td><code>RC2-CBC-MD5</code></td> <td>SSLv2</td> <td>RSA</td> <td>RSA</td> <td>RC2(128)</td> <td>MD5</td> <td></td> </tr>
692 <tr><td><code>RC4-MD5</code></td> <td>SSLv2</td> <td>RSA</td> <td>RSA</td> <td>RC4(128)</td> <td>MD5</td> <td></td> </tr>
693 <tr><td><code>DES-CBC-SHA</code></td> <td>SSLv3</td> <td>RSA</td> <td>RSA</td> <td>DES(56)</td> <td>SHA1</td> <td></td> </tr>
694 <tr><td><code>RC4-64-MD5</code></td> <td>SSLv2</td> <td>RSA</td> <td>RSA</td> <td>RC4(64)</td> <td>MD5</td> <td></td> </tr>
695 <tr><td><code>DES-CBC-MD5</code></td> <td>SSLv2</td> <td>RSA</td> <td>RSA</td> <td>DES(56)</td> <td>MD5</td> <td></td> </tr>
696 <tr><td><code>EXP-DES-CBC-SHA</code></td> <td>SSLv3</td> <td>RSA(512)</td> <td>RSA</td> <td>DES(40)</td> <td>SHA1</td> <td> export</td> </tr>
697 <tr><td><code>EXP-RC2-CBC-MD5</code></td> <td>SSLv3</td> <td>RSA(512)</td> <td>RSA</td> <td>RC2(40)</td> <td>MD5</td> <td> export</td> </tr>
698 <tr><td><code>EXP-RC4-MD5</code></td> <td>SSLv3</td> <td>RSA(512)</td> <td>RSA</td> <td>RC4(40)</td> <td>MD5</td> <td> export</td> </tr>
699 <tr><td><code>EXP-RC2-CBC-MD5</code></td> <td>SSLv2</td> <td>RSA(512)</td> <td>RSA</td> <td>RC2(40)</td> <td>MD5</td> <td> export</td> </tr>
700 <tr><td><code>EXP-RC4-MD5</code></td> <td>SSLv2</td> <td>RSA(512)</td> <td>RSA</td> <td>RC4(40)</td> <td>MD5</td> <td> export</td> </tr>
701 <tr><td><code>NULL-SHA</code></td> <td>SSLv3</td> <td>RSA</td> <td>RSA</td> <td>None</td> <td>SHA1</td> <td></td> </tr>
702 <tr><td><code>NULL-MD5</code></td> <td>SSLv3</td> <td>RSA</td> <td>RSA</td> <td>None</td> <td>MD5</td> <td></td> </tr>
703 <tr><td colspan="7"><em>Diffie-Hellman Ciphers:</em></td></tr>
704 <tr><td><code>ADH-DES-CBC3-SHA</code></td> <td>SSLv3</td> <td>DH</td> <td>None</td> <td>3DES(168)</td> <td>SHA1</td> <td></td> </tr>
705 <tr><td><code>ADH-DES-CBC-SHA</code></td> <td>SSLv3</td> <td>DH</td> <td>None</td> <td>DES(56)</td> <td>SHA1</td> <td></td> </tr>
706 <tr><td><code>ADH-RC4-MD5</code></td> <td>SSLv3</td> <td>DH</td> <td>None</td> <td>RC4(128)</td> <td>MD5</td> <td></td> </tr>
707 <tr><td><code>EDH-RSA-DES-CBC3-SHA</code></td> <td>SSLv3</td> <td>DH</td> <td>RSA</td> <td>3DES(168)</td> <td>SHA1</td> <td></td> </tr>
708 <tr><td><code>EDH-DSS-DES-CBC3-SHA</code></td> <td>SSLv3</td> <td>DH</td> <td>DSS</td> <td>3DES(168)</td> <td>SHA1</td> <td></td> </tr>
709 <tr><td><code>EDH-RSA-DES-CBC-SHA</code></td> <td>SSLv3</td> <td>DH</td> <td>RSA</td> <td>DES(56)</td> <td>SHA1</td> <td></td> </tr>
710 <tr><td><code>EDH-DSS-DES-CBC-SHA</code></td> <td>SSLv3</td> <td>DH</td> <td>DSS</td> <td>DES(56)</td> <td>SHA1</td> <td></td> </tr>
711 <tr><td><code>EXP-EDH-RSA-DES-CBC-SHA</code></td> <td>SSLv3</td> <td>DH(512)</td> <td>RSA</td> <td>DES(40)</td> <td>SHA1</td> <td> export</td> </tr>
712 <tr><td><code>EXP-EDH-DSS-DES-CBC-SHA</code></td> <td>SSLv3</td> <td>DH(512)</td> <td>DSS</td> <td>DES(40)</td> <td>SHA1</td> <td> export</td> </tr>
713 <tr><td><code>EXP-ADH-DES-CBC-SHA</code></td> <td>SSLv3</td> <td>DH(512)</td> <td>None</td> <td>DES(40)</td> <td>SHA1</td> <td> export</td> </tr>
714 <tr><td><code>EXP-ADH-RC4-MD5</code></td> <td>SSLv3</td> <td>DH(512)</td> <td>None</td> <td>RC4(40)</td> <td>MD5</td> <td> export</td> </tr>
720 <name>SSLCertificateFile</name>
721 <description>Server PEM-encoded X.509 Certificate file</description>
722 <syntax>SSLCertificateFile <em>file-path</em></syntax>
723 <contextlist><context>server config</context>
724 <context>virtual host</context></contextlist>
728 This directive points to the PEM-encoded Certificate file for the server and
729 optionally also to the corresponding RSA or DSA Private Key file for it
730 (contained in the same file). If the contained Private Key is encrypted the
731 Pass Phrase dialog is forced at startup time. This directive can be used up to
732 two times (referencing different filenames) when both a RSA and a DSA based
733 server certificate is used in parallel.</p>
734 <example><title>Example</title>
735 SSLCertificateFile /usr/local/apache2/conf/ssl.crt/server.crt
741 <name>SSLCertificateKeyFile</name>
742 <description>Server PEM-encoded Private Key file</description>
743 <syntax>SSLCertificateKeyFile <em>file-path</em></syntax>
744 <contextlist><context>server config</context>
745 <context>virtual host</context></contextlist>
749 This directive points to the PEM-encoded Private Key file for the
750 server. If the Private Key is not combined with the Certificate in the
751 <directive>SSLCertificateFile</directive>, use this additional directive to
752 point to the file with the stand-alone Private Key. When
753 <directive>SSLCertificateFile</directive> is used and the file
754 contains both the Certificate and the Private Key this directive need
755 not be used. But we strongly discourage this practice. Instead we
756 recommend you to separate the Certificate and the Private Key. If the
757 contained Private Key is encrypted, the Pass Phrase dialog is forced
758 at startup time. This directive can be used up to two times
759 (referencing different filenames) when both a RSA and a DSA based
760 private key is used in parallel.</p>
761 <example><title>Example</title>
762 SSLCertificateKeyFile /usr/local/apache2/conf/ssl.key/server.key
768 <name>SSLCertificateChainFile</name>
769 <description>File of PEM-encoded Server CA Certificates</description>
770 <syntax>SSLCertificateChainFile <em>file-path</em></syntax>
771 <contextlist><context>server config</context>
772 <context>virtual host</context></contextlist>
776 This directive sets the optional <em>all-in-one</em> file where you can
777 assemble the certificates of Certification Authorities (CA) which form the
778 certificate chain of the server certificate. This starts with the issuing CA
779 certificate of of the server certificate and can range up to the root CA
780 certificate. Such a file is simply the concatenation of the various
781 PEM-encoded CA Certificate files, usually in certificate chain order.</p>
783 This should be used alternatively and/or additionally to <directive
784 module="mod_ssl">SSLCACertificatePath</directive> for explicitly
785 constructing the server certificate chain which is sent to the browser
786 in addition to the server certificate. It is especially useful to
787 avoid conflicts with CA certificates when using client
788 authentication. Because although placing a CA certificate of the
789 server certificate chain into <directive
790 module="mod_ssl">SSLCACertificatePath</directive> has the same effect
791 for the certificate chain construction, it has the side-effect that
792 client certificates issued by this same CA certificate are also
793 accepted on client authentication. That's usually not one expect.</p>
795 But be careful: Providing the certificate chain works only if you are using a
796 <em>single</em> (either RSA <em>or</em> DSA) based server certificate. If you are
797 using a coupled RSA+DSA certificate pair, this will work only if actually both
798 certificates use the <em>same</em> certificate chain. Else the browsers will be
799 confused in this situation.</p>
800 <example><title>Example</title>
801 SSLCertificateChainFile /usr/local/apache2/conf/ssl.crt/ca.crt
807 <name>SSLCACertificatePath</name>
808 <description>Directory of PEM-encoded CA Certificates for
809 Client Auth</description>
810 <syntax>SSLCACertificatePath <em>directory-path</em></syntax>
811 <contextlist><context>server config</context>
812 <context>virtual host</context></contextlist>
816 This directive sets the directory where you keep the Certificates of
817 Certification Authorities (CAs) whose clients you deal with. These are used to
818 verify the client certificate on Client Authentication.</p>
820 The files in this directory have to be PEM-encoded and are accessed through
821 hash filenames. So usually you can't just place the Certificate files
822 there: you also have to create symbolic links named
823 <em>hash-value</em><code>.N</code>. And you should always make sure this directory
824 contains the appropriate symbolic links. Use the <code>Makefile</code> which
825 comes with mod_ssl to accomplish this task.</p>
826 <example><title>Example</title>
827 SSLCACertificatePath /usr/local/apache2/conf/ssl.crt/
833 <name>SSLCACertificateFile</name>
834 <description>File of concatenated PEM-encoded CA Certificates
835 for Client Auth</description>
836 <syntax>SSLCACertificateFile <em>file-path</em></syntax>
837 <contextlist><context>server config</context>
838 <context>virtual host</context></contextlist>
842 This directive sets the <em>all-in-one</em> file where you can assemble the
843 Certificates of Certification Authorities (CA) whose <em>clients</em> you deal
844 with. These are used for Client Authentication. Such a file is simply the
845 concatenation of the various PEM-encoded Certificate files, in order of
846 preference. This can be used alternatively and/or additionally to
847 <directive module="mod_ssl">SSLCACertificatePath</directive>.</p>
848 <example><title>Example</title>
849 SSLCACertificateFile /usr/local/apache2/conf/ssl.crt/ca-bundle-client.crt
855 <name>SSLCADNRequestFile</name>
856 <description>File of concatenated PEM-encoded CA Certificates
857 for defining acceptable CA names</description>
858 <syntax>SSLCADNRequestFile <em>file-path</em></syntax>
859 <contextlist><context>server config</context>
860 <context>virtual host</context></contextlist>
863 <p>When a client certificate is requested by mod_ssl, a list of
864 <em>acceptable Certificate Authority names</em> is sent to the client
865 in the SSL handshake. These CA names can be used by the client to
866 select an appropriate client certificate out of those it has
869 <p>If neither of the directives <directive
870 module="mod_ssl">SSLCADNRequestPath</directive> or <directive
871 module="mod_ssl">SSLCADNRequestFile</directive> are given, then the
872 set of acceptable CA names sent to the client is the names of all the
873 CA certificates given by the <directive
874 module="mod_ssl">SSLCACertificateFile</directive> and <directive
875 module="mod_ssl">SSLCACertificatePath</directive> directives; in other
876 words, the names of the CAs which will actually be used to verify the
877 client certificate.</p>
879 <p>In some circumstances, it is useful to be able to send a set of
880 acceptable CA names which differs from the actual CAs used to verify
881 the client certificate - for example, if the client certificates are
882 signed by intermediate CAs. In such cases, <directive
883 module="mod_ssl">SSLCADNRequestPath</directive> and/or <directive
884 module="mod_ssl">SSLCADNRequestFile</directive> can be used; the
885 acceptable CA names are then taken from the complete set of
886 certificates in the directory and/or file specified by this pair of
889 <p><directive module="mod_ssl">SSLCADNRequestFile</directive> must
890 specify an <em>all-in-one</em> file containing a concatenation of
891 PEM-encoded CA certificates.</p>
893 <example><title>Example</title>
894 SSLCADNRequestFile /usr/local/apache2/conf/ca-names.crt
900 <name>SSLCADNRequestPath</name>
901 <description>Directory of PEM-encoded CA Certificates for
902 defining acceptable CA names</description>
903 <syntax>SSLCADNRequestPath <em>directory-path</em></syntax>
904 <contextlist><context>server config</context>
905 <context>virtual host</context></contextlist>
909 <p>This optional directive can be used to specify the set of
910 <em>acceptable CA names</em> which will be sent to the client when a
911 client certificate is requested. See the <directive
912 module="mod_ssl">SSLCADNRequestFile</directive> directive for more
915 <p>The files in this directory have to be PEM-encoded and are accessed
916 through hash filenames. So usually you can't just place the
917 Certificate files there: you also have to create symbolic links named
918 <em>hash-value</em><code>.N</code>. And you should always make sure
919 this directory contains the appropriate symbolic links. Use the
920 <code>Makefile</code> which comes with mod_ssl to accomplish this
922 <example><title>Example</title>
923 SSLCADNRequestPath /usr/local/apache2/conf/ca-names.crt/
929 <name>SSLCARevocationPath</name>
930 <description>Directory of PEM-encoded CA CRLs for
931 Client Auth</description>
932 <syntax>SSLCARevocationPath <em>directory-path</em></syntax>
933 <contextlist><context>server config</context>
934 <context>virtual host</context></contextlist>
938 This directive sets the directory where you keep the Certificate Revocation
939 Lists (CRL) of Certification Authorities (CAs) whose clients you deal with.
940 These are used to revoke the client certificate on Client Authentication.</p>
942 The files in this directory have to be PEM-encoded and are accessed through
943 hash filenames. So usually you have not only to place the CRL files there.
944 Additionally you have to create symbolic links named
945 <em>hash-value</em><code>.rN</code>. And you should always make sure this directory
946 contains the appropriate symbolic links. Use the <code>Makefile</code> which
947 comes with <module>mod_ssl</module> to accomplish this task.</p>
948 <example><title>Example</title>
949 SSLCARevocationPath /usr/local/apache2/conf/ssl.crl/
955 <name>SSLCARevocationFile</name>
956 <description>File of concatenated PEM-encoded CA CRLs for
957 Client Auth</description>
958 <syntax>SSLCARevocationFile <em>file-path</em></syntax>
959 <contextlist><context>server config</context>
960 <context>virtual host</context></contextlist>
964 This directive sets the <em>all-in-one</em> file where you can
965 assemble the Certificate Revocation Lists (CRL) of Certification
966 Authorities (CA) whose <em>clients</em> you deal with. These are used
967 for Client Authentication. Such a file is simply the concatenation of
968 the various PEM-encoded CRL files, in order of preference. This can be
969 used alternatively and/or additionally to <directive
970 module="mod_ssl">SSLCARevocationPath</directive>.</p>
971 <example><title>Example</title>
972 SSLCARevocationFile /usr/local/apache2/conf/ssl.crl/ca-bundle-client.crl
978 <name>SSLVerifyClient</name>
979 <description>Type of Client Certificate verification</description>
980 <syntax>SSLVerifyClient <em>level</em></syntax>
981 <default>SSLVerifyClient none</default>
982 <contextlist><context>server config</context>
983 <context>virtual host</context>
984 <context>directory</context>
985 <context>.htaccess</context></contextlist>
986 <override>AuthConfig</override>
990 This directive sets the Certificate verification level for the Client
991 Authentication. Notice that this directive can be used both in per-server and
992 per-directory context. In per-server context it applies to the client
993 authentication process used in the standard SSL handshake when a connection is
994 established. In per-directory context it forces a SSL renegotation with the
995 reconfigured client verification level after the HTTP request was read but
996 before the HTTP response is sent.</p>
998 The following levels are available for <em>level</em>:</p>
1000 <li><strong>none</strong>:
1001 no client Certificate is required at all</li>
1002 <li><strong>optional</strong>:
1003 the client <em>may</em> present a valid Certificate</li>
1004 <li><strong>require</strong>:
1005 the client <em>has to</em> present a valid Certificate</li>
1006 <li><strong>optional_no_ca</strong>:
1007 the client may present a valid Certificate<br />
1008 but it need not to be (successfully) verifiable.</li>
1010 <p>In practice only levels <strong>none</strong> and
1011 <strong>require</strong> are really interesting, because level
1012 <strong>optional</strong> doesn't work with all browsers and level
1013 <strong>optional_no_ca</strong> is actually against the idea of
1014 authentication (but can be used to establish SSL test pages, etc.)</p>
1015 <example><title>Example</title>
1016 SSLVerifyClient require
1019 </directivesynopsis>
1022 <name>SSLVerifyDepth</name>
1023 <description>Maximum depth of CA Certificates in Client
1024 Certificate verification</description>
1025 <syntax>SSLVerifyDepth <em>number</em></syntax>
1026 <default>SSLVerifyDepth 1</default>
1027 <contextlist><context>server config</context>
1028 <context>virtual host</context>
1029 <context>directory</context>
1030 <context>.htaccess</context></contextlist>
1031 <override>AuthConfig</override>
1035 This directive sets how deeply mod_ssl should verify before deciding that the
1036 clients don't have a valid certificate. Notice that this directive can be
1037 used both in per-server and per-directory context. In per-server context it
1038 applies to the client authentication process used in the standard SSL
1039 handshake when a connection is established. In per-directory context it forces
1040 a SSL renegotation with the reconfigured client verification depth after the
1041 HTTP request was read but before the HTTP response is sent.</p>
1043 The depth actually is the maximum number of intermediate certificate issuers,
1044 i.e. the number of CA certificates which are max allowed to be followed while
1045 verifying the client certificate. A depth of 0 means that self-signed client
1046 certificates are accepted only, the default depth of 1 means the client
1047 certificate can be self-signed or has to be signed by a CA which is directly
1048 known to the server (i.e. the CA's certificate is under
1049 <directive module="mod_ssl">SSLCACertificatePath</directive>), etc.</p>
1050 <example><title>Example</title>
1054 </directivesynopsis>
1057 <name>SSLOptions</name>
1058 <description>Configure various SSL engine run-time options</description>
1059 <syntax>SSLOptions [+|-]<em>option</em> ...</syntax>
1060 <contextlist><context>server config</context>
1061 <context>virtual host</context>
1062 <context>directory</context>
1063 <context>.htaccess</context></contextlist>
1064 <override>Options</override>
1068 This directive can be used to control various run-time options on a
1069 per-directory basis. Normally, if multiple <code>SSLOptions</code>
1070 could apply to a directory, then the most specific one is taken
1071 completely; the options are not merged. However if <em>all</em> the
1072 options on the <code>SSLOptions</code> directive are preceded by a
1073 plus (<code>+</code>) or minus (<code>-</code>) symbol, the options
1074 are merged. Any options preceded by a <code>+</code> are added to the
1075 options currently in force, and any options preceded by a
1076 <code>-</code> are removed from the options currently in force.</p>
1078 The available <em>option</em>s are:</p>
1080 <li><code>StdEnvVars</code>
1082 When this option is enabled, the standard set of SSL related CGI/SSI
1083 environment variables are created. This per default is disabled for
1084 performance reasons, because the information extraction step is a
1085 rather expensive operation. So one usually enables this option for
1086 CGI and SSI requests only.</p>
1088 <li><code>CompatEnvVars</code>
1090 When this option is enabled, additional CGI/SSI environment variables are
1091 created for backward compatibility to other Apache SSL solutions. Look in
1092 the <a href="../ssl/ssl_compat.html">Compatibility</a> chapter for details
1093 on the particular variables generated.</p>
1095 <li><code>ExportCertData</code>
1097 When this option is enabled, additional CGI/SSI environment variables are
1098 created: <code>SSL_SERVER_CERT</code>, <code>SSL_CLIENT_CERT</code> and
1099 <code>SSL_CLIENT_CERT_CHAIN_</code><em>n</em> (with <em>n</em> = 0,1,2,..).
1100 These contain the PEM-encoded X.509 Certificates of server and client for
1101 the current HTTPS connection and can be used by CGI scripts for deeper
1102 Certificate checking. Additionally all other certificates of the client
1103 certificate chain are provided, too. This bloats up the environment a
1104 little bit which is why you have to use this option to enable it on
1107 <li><code>FakeBasicAuth</code>
1109 When this option is enabled, the Subject Distinguished Name (DN) of the
1110 Client X509 Certificate is translated into a HTTP Basic Authorization
1111 username. This means that the standard Apache authentication methods can
1112 be used for access control. The user name is just the Subject of the
1113 Client's X509 Certificate (can be determined by running OpenSSL's
1114 <code>openssl x509</code> command: <code>openssl x509 -noout -subject -in
1115 </code><em>certificate</em><code>.crt</code>). Note that no password is
1116 obtained from the user. Every entry in the user file needs this password:
1117 ``<code>xxj31ZMTZzkVA</code>'', which is the DES-encrypted version of the
1118 word `<code>password</code>''. Those who live under MD5-based encryption
1119 (for instance under FreeBSD or BSD/OS, etc.) should use the following MD5
1120 hash of the same word: ``<code>$1$OXLyS...$Owx8s2/m9/gfkcRVXzgoE/</code>''.</p>
1122 <li><code>StrictRequire</code>
1124 This <em>forces</em> forbidden access when <code>SSLRequireSSL</code> or
1125 <code>SSLRequire</code> successfully decided that access should be
1126 forbidden. Usually the default is that in the case where a ``<code>Satisfy
1127 any</code>'' directive is used, and other access restrictions are passed,
1128 denial of access due to <code>SSLRequireSSL</code> or
1129 <code>SSLRequire</code> is overridden (because that's how the Apache
1130 <code>Satisfy</code> mechanism should work.) But for strict access restriction
1131 you can use <code>SSLRequireSSL</code> and/or <code>SSLRequire</code> in
1132 combination with an ``<code>SSLOptions +StrictRequire</code>''. Then an
1133 additional ``<code>Satisfy Any</code>'' has no chance once mod_ssl has
1134 decided to deny access.</p>
1136 <li><code>OptRenegotiate</code>
1138 This enables optimized SSL connection renegotiation handling when SSL
1139 directives are used in per-directory context. By default a strict
1140 scheme is enabled where <em>every</em> per-directory reconfiguration of
1141 SSL parameters causes a <em>full</em> SSL renegotiation handshake. When this
1142 option is used mod_ssl tries to avoid unnecessary handshakes by doing more
1143 granular (but still safe) parameter checks. Nevertheless these granular
1144 checks sometimes maybe not what the user expects, so enable this on a
1145 per-directory basis only, please.</p>
1148 <example><title>Example</title>
1149 SSLOptions +FakeBasicAuth -StrictRequire<br />
1150 <Files ~ "\.(cgi|shtml)$"><br />
1151 SSLOptions +StdEnvVars +CompatEnvVars -ExportCertData<br />
1155 </directivesynopsis>
1158 <name>SSLRequireSSL</name>
1159 <description>Deny access when SSL is not used for the
1160 HTTP request</description>
1161 <syntax>SSLRequireSSL</syntax>
1162 <contextlist><context>directory</context>
1163 <context>.htaccess</context></contextlist>
1164 <override>AuthConfig</override>
1167 <p><!-- XXX: I think the syntax is wrong -->
1168 This directive forbids access unless HTTP over SSL (i.e. HTTPS) is enabled for
1169 the current connection. This is very handy inside the SSL-enabled virtual
1170 host or directories for defending against configuration errors that expose
1171 stuff that should be protected. When this directive is present all requests
1172 are denied which are not using SSL.</p>
1173 <example><title>Example</title>
1177 </directivesynopsis>
1180 <name>SSLRequire</name>
1181 <description>Allow access only when an arbitrarily complex
1182 boolean expression is true</description>
1183 <syntax>SSLRequire <em>expression</em></syntax>
1184 <contextlist><context>directory</context>
1185 <context>.htaccess</context></contextlist>
1186 <override>AuthConfig</override>
1190 This directive specifies a general access requirement which has to be
1191 fulfilled in order to allow access. It is a very powerful directive because the
1192 requirement specification is an arbitrarily complex boolean expression
1193 containing any number of access checks.</p>
1194 <note type="warning">
1195 <p>The implementation of <code>SSLRequire</code> is not thread safe.
1196 Using <code>SSLRequire</code> inside <code>.htaccess</code> files
1197 on a threaded <a href="../mpm.html">MPM</a> may cause random crashes.
1201 The <em>expression</em> must match the following syntax (given as a BNF
1202 grammar notation):</p>
1205 expr ::= "<strong>true</strong>" | "<strong>false</strong>"
1206 | "<strong>!</strong>" expr
1207 | expr "<strong>&&</strong>" expr
1208 | expr "<strong>||</strong>" expr
1209 | "<strong>(</strong>" expr "<strong>)</strong>"
1212 comp ::= word "<strong>==</strong>" word | word "<strong>eq</strong>" word
1213 | word "<strong>!=</strong>" word | word "<strong>ne</strong>" word
1214 | word "<strong><</strong>" word | word "<strong>lt</strong>" word
1215 | word "<strong><=</strong>" word | word "<strong>le</strong>" word
1216 | word "<strong>></strong>" word | word "<strong>gt</strong>" word
1217 | word "<strong>>=</strong>" word | word "<strong>ge</strong>" word
1218 | word "<strong>in</strong>" "<strong>{</strong>" wordlist "<strong>}</strong>"
1219 | word "<strong>in</strong>" "<strong>PeerExtList(</strong>" word "<strong>)</strong>"
1220 | word "<strong>=~</strong>" regex
1221 | word "<strong>!~</strong>" regex
1224 | wordlist "<strong>,</strong>" word
1233 variable ::= "<strong>%{</strong>" varname "<strong>}</strong>"
1234 function ::= funcname "<strong>(</strong>" funcargs "<strong>)</strong>"
1237 <p>while for <code>varname</code> any variable from <a
1238 href="#table3">Table 3</a> can be used. Finally for
1239 <code>funcname</code> the following functions are available:</p>
1241 <li><code>file(</code><em>filename</em><code>)</code>
1243 This function takes one string argument and expands to the contents of the
1244 file. This is especially useful for matching this contents against a
1245 regular expression, etc.</p>
1248 <p>Notice that <em>expression</em> is first parsed into an internal machine
1249 representation and then evaluated in a second step. Actually, in Global and
1250 Per-Server Class context <em>expression</em> is parsed at startup time and
1251 at runtime only the machine representation is executed. For Per-Directory
1252 context this is different: here <em>expression</em> has to be parsed and
1253 immediately executed for every request.</p>
1254 <example><title>Example</title>
1255 SSLRequire ( %{SSL_CIPHER} !~ m/^(EXP|NULL)-/ \<br />
1256 and %{SSL_CLIENT_S_DN_O} eq "Snake Oil, Ltd." \<br />
1257 and %{SSL_CLIENT_S_DN_OU} in {"Staff", "CA", "Dev"} \<br />
1258 and %{TIME_WDAY} >= 1 and %{TIME_WDAY} <= 5 \<br />
1259 and %{TIME_HOUR} >= 8 and %{TIME_HOUR} <= 20 ) \<br />
1260 or %{REMOTE_ADDR} =~ m/^192\.76\.162\.[0-9]+$/
1262 <p>The <code>PeerExtList(<em>object id</em>)</code> function expects to find
1263 zero or more instances of the X.509 Certificate Extension (as identified by
1264 the given <em>object id</em>) in the client certificate, and compares the
1265 left-hand side string against the value of any matching attribute value. Every
1266 extension with the specified object id is checked, until a match is found.
1269 <p><em>Standard CGI/1.0 and Apache variables:</em></p>
1271 HTTP_USER_AGENT PATH_INFO AUTH_TYPE
1272 HTTP_REFERER QUERY_STRING SERVER_SOFTWARE
1273 HTTP_COOKIE REMOTE_HOST API_VERSION
1274 HTTP_FORWARDED REMOTE_IDENT TIME_YEAR
1275 HTTP_HOST IS_SUBREQ TIME_MON
1276 HTTP_PROXY_CONNECTION DOCUMENT_ROOT TIME_DAY
1277 HTTP_ACCEPT SERVER_ADMIN TIME_HOUR
1278 HTTP:headername SERVER_NAME TIME_MIN
1279 THE_REQUEST SERVER_PORT TIME_SEC
1280 REQUEST_METHOD SERVER_PROTOCOL TIME_WDAY
1281 REQUEST_SCHEME REMOTE_ADDR TIME
1282 REQUEST_URI REMOTE_USER ENV:<strong>variablename</strong>
1285 <p><em>SSL-related variables:</em></p>
1287 HTTPS SSL_CLIENT_M_VERSION SSL_SERVER_M_VERSION
1288 SSL_CLIENT_M_SERIAL SSL_SERVER_M_SERIAL
1289 SSL_PROTOCOL SSL_CLIENT_V_START SSL_SERVER_V_START
1290 SSL_SESSION_ID SSL_CLIENT_V_END SSL_SERVER_V_END
1291 SSL_CIPHER SSL_CLIENT_S_DN SSL_SERVER_S_DN
1292 SSL_CIPHER_EXPORT SSL_CLIENT_S_DN_C SSL_SERVER_S_DN_C
1293 SSL_CIPHER_ALGKEYSIZE SSL_CLIENT_S_DN_ST SSL_SERVER_S_DN_ST
1294 SSL_CIPHER_USEKEYSIZE SSL_CLIENT_S_DN_L SSL_SERVER_S_DN_L
1295 SSL_VERSION_LIBRARY SSL_CLIENT_S_DN_O SSL_SERVER_S_DN_O
1296 SSL_VERSION_INTERFACE SSL_CLIENT_S_DN_OU SSL_SERVER_S_DN_OU
1297 SSL_CLIENT_S_DN_CN SSL_SERVER_S_DN_CN
1298 SSL_CLIENT_S_DN_T SSL_SERVER_S_DN_T
1299 SSL_CLIENT_S_DN_I SSL_SERVER_S_DN_I
1300 SSL_CLIENT_S_DN_G SSL_SERVER_S_DN_G
1301 SSL_CLIENT_S_DN_S SSL_SERVER_S_DN_S
1302 SSL_CLIENT_S_DN_D SSL_SERVER_S_DN_D
1303 SSL_CLIENT_S_DN_UID SSL_SERVER_S_DN_UID
1304 SSL_CLIENT_S_DN_Email SSL_SERVER_S_DN_Email
1305 SSL_CLIENT_I_DN SSL_SERVER_I_DN
1306 SSL_CLIENT_I_DN_C SSL_SERVER_I_DN_C
1307 SSL_CLIENT_I_DN_ST SSL_SERVER_I_DN_ST
1308 SSL_CLIENT_I_DN_L SSL_SERVER_I_DN_L
1309 SSL_CLIENT_I_DN_O SSL_SERVER_I_DN_O
1310 SSL_CLIENT_I_DN_OU SSL_SERVER_I_DN_OU
1311 SSL_CLIENT_I_DN_CN SSL_SERVER_I_DN_CN
1312 SSL_CLIENT_I_DN_T SSL_SERVER_I_DN_T
1313 SSL_CLIENT_I_DN_I SSL_SERVER_I_DN_I
1314 SSL_CLIENT_I_DN_G SSL_SERVER_I_DN_G
1315 SSL_CLIENT_I_DN_S SSL_SERVER_I_DN_S
1316 SSL_CLIENT_I_DN_D SSL_SERVER_I_DN_D
1317 SSL_CLIENT_I_DN_UID SSL_SERVER_I_DN_UID
1318 SSL_CLIENT_I_DN_Email SSL_SERVER_I_DN_Email
1319 SSL_CLIENT_A_SIG SSL_SERVER_A_SIG
1320 SSL_CLIENT_A_KEY SSL_SERVER_A_KEY
1321 SSL_CLIENT_CERT SSL_SERVER_CERT
1322 SSL_CLIENT_CERT_CHAIN_<strong>n</strong>
1326 </directivesynopsis>
1329 <name>SSLProxyMachineCertificatePath</name>
1330 <description>Directory of PEM-encoded client certificates and keys to be used by the proxy</description>
1331 <syntax>SSLProxyMachineCertificatePath <em>directory</em></syntax>
1332 <contextlist><context>server config</context></contextlist>
1333 <override>Not applicable</override>
1337 This directive sets the directory where you keep the certificates and
1338 keys used for authentication of the proxy server to remote servers.
1340 <p>The files in this directory must be PEM-encoded and are accessed through
1341 hash filenames. Additionally, you must create symbolic links named
1342 <code><em>hash-value</em>.N</code>. And you should always make sure this
1343 directory contains the appropriate symbolic links. Use the Makefile which
1344 comes with mod_ssl to accomplish this task.
1346 <note type="warning">
1347 <p>Currently there is no support for encrypted private keys</p>
1349 <example><title>Example</title>
1350 SSLProxyMachineCertificatePath /usr/local/apache2/conf/proxy.crt/
1353 </directivesynopsis>
1357 <name>SSLProxyMachineCertificateFile</name>
1358 <description>File of concatenated PEM-encoded client certificates and keys to be used by the proxy</description>
1359 <syntax>SSLProxyMachineCertificateFile <em>filename</em></syntax>
1360 <contextlist><context>server config</context></contextlist>
1361 <override>Not applicable</override>
1365 This directive sets the all-in-one file where you keep the certificates and
1366 keys used for authentication of the proxy server to remote servers.
1369 This referenced file is simply the concatenation of the various PEM-encoded
1370 certificate files, in order of preference. Use this directive alternatively
1371 or additionally to <code>SSLProxyMachineCertificatePath</code>.
1373 <note type="warning">
1374 <p>Currently there is no support for encrypted private keys</p>
1376 <example><title>Example</title>
1377 SSLProxyMachineCertificateFile /usr/local/apache2/conf/ssl.crt/proxy.pem
1380 </directivesynopsis>
1383 <name>SSLProxyVerify</name>
1384 <description>Type of remote server Certificate verification</description>
1385 <syntax>SSLProxyVerify <em>level</em></syntax>
1386 <default>SSLProxyVerify none</default>
1387 <contextlist><context>server config</context>
1388 <context>virtual host</context>
1389 <context>directory</context>
1390 <context>.htaccess</context></contextlist>
1391 <override>AuthConfig</override>
1395 <p>When a proxy is configured to forward requests to a remote SSL
1396 server, this directive can be used to configure certificate
1397 verification of the remote server. Notice that this directive can be
1398 used both in per-server and per-directory context. In per-server
1399 context it applies to the remote server authentication process used in
1400 the standard SSL handshake when a connection is established by the
1401 proxy. In per-directory context it forces a SSL renegotation with the
1402 reconfigured remote server verification level after the HTTP request
1403 was read but before the HTTP response is sent.</p>
1405 <note type="warning">
1406 <p>Note that even when certificate verification is enabled,
1407 <module>mod_ssl</module> does <strong>not</strong> check whether the
1408 <code>commonName</code> (hostname) attribute of the server certificate
1409 matches the hostname used to connect to the server. In other words,
1410 the proxy does not guarantee that the SSL connection to the backend
1411 server is "secure" beyond the fact that the certificate is signed by
1412 one of the CAs configured using the
1413 <directive>SSLProxyCACertificatePath</directive> and/or
1414 <directive>SSLProxyCACertificateFile</directive> directives.</p>
1418 The following levels are available for <em>level</em>:</p>
1420 <li><strong>none</strong>:
1421 no remote server Certificate is required at all</li>
1422 <li><strong>optional</strong>:
1423 the remote server <em>may</em> present a valid Certificate</li>
1424 <li><strong>require</strong>:
1425 the remote server <em>has to</em> present a valid Certificate</li>
1426 <li><strong>optional_no_ca</strong>:
1427 the remote server may present a valid Certificate<br />
1428 but it need not to be (successfully) verifiable.</li>
1430 <p>In practice only levels <strong>none</strong> and
1431 <strong>require</strong> are really interesting, because level
1432 <strong>optional</strong> doesn't work with all servers and level
1433 <strong>optional_no_ca</strong> is actually against the idea of
1434 authentication (but can be used to establish SSL test pages, etc.)</p>
1435 <example><title>Example</title>
1436 SSLProxyVerify require
1439 </directivesynopsis>
1442 <name>SSLProxyVerifyDepth</name>
1443 <description>Maximum depth of CA Certificates in Remote Server
1444 Certificate verification</description>
1445 <syntax>SSLProxyVerifyDepth <em>number</em></syntax>
1446 <default>SSLProxyVerifyDepth 1</default>
1447 <contextlist><context>server config</context>
1448 <context>virtual host</context>
1449 <context>directory</context>
1450 <context>.htaccess</context></contextlist>
1451 <override>AuthConfig</override>
1455 This directive sets how deeply mod_ssl should verify before deciding that the
1456 remote server does not have a valid certificate. Notice that this directive can be
1457 used both in per-server and per-directory context. In per-server context it
1458 applies to the client authentication process used in the standard SSL
1459 handshake when a connection is established. In per-directory context it forces
1460 a SSL renegotation with the reconfigured remote server verification depth after the
1461 HTTP request was read but before the HTTP response is sent.</p>
1463 The depth actually is the maximum number of intermediate certificate issuers,
1464 i.e. the number of CA certificates which are max allowed to be followed while
1465 verifying the remote server certificate. A depth of 0 means that self-signed
1466 remote server certificates are accepted only, the default depth of 1 means
1467 the remote server certificate can be self-signed or has to be signed by a CA
1468 which is directly known to the server (i.e. the CA's certificate is under
1469 <directive module="mod_ssl">SSLProxyCACertificatePath</directive>), etc.</p>
1470 <example><title>Example</title>
1471 SSLProxyVerifyDepth 10
1474 </directivesynopsis>
1477 <name>SSLProxyEngine</name>
1478 <description>SSL Proxy Engine Operation Switch</description>
1479 <syntax>SSLProxyEngine on|off</syntax>
1480 <default>SSLProxyEngine off</default>
1481 <contextlist><context>server config</context>
1482 <context>virtual host</context></contextlist>
1486 This directive toggles the usage of the SSL/TLS Protocol Engine for proxy. This
1487 is usually used inside a <directive module="core"
1488 type="section">VirtualHost</directive> section to enable SSL/TLS for proxy
1489 usage in a particular virtual host. By default the SSL/TLS Protocol Engine is
1490 disabled for proxy image both for the main server and all configured virtual hosts.</p>
1491 <example><title>Example</title>
1492 <VirtualHost _default_:443><br />
1493 SSLProxyEngine on<br />
1495 </VirtualHost>
1498 </directivesynopsis>
1501 <name>SSLProxyProtocol</name>
1502 <description>Configure usable SSL protocol flavors for proxy usage</description>
1503 <syntax>SSLProxyProtocol [+|-]<em>protocol</em> ...</syntax>
1504 <default>SSLProxyProtocol all</default>
1505 <contextlist><context>server config</context>
1506 <context>virtual host</context></contextlist>
1507 <override>Options</override>
1510 <!-- XXX Why does this have an override and not .htaccess context? -->
1512 This directive can be used to control the SSL protocol flavors mod_ssl should
1513 use when establishing its server environment for proxy . It will only connect
1514 to servers using one of the provided protocols.</p>
1515 <p>Please refer to <directive module="mod_ssl">SSLProtocol</directive>
1516 for additional information.
1519 </directivesynopsis>
1522 <name>SSLProxyCipherSuite</name>
1523 <description>Cipher Suite available for negotiation in SSL
1524 proxy handshake</description>
1525 <syntax>SSLProxyCipherSuite <em>cipher-spec</em></syntax>
1526 <default>SSLProxyCipherSuite ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP</default>
1527 <contextlist><context>server config</context>
1528 <context>virtual host</context>
1529 <context>directory</context>
1530 <context>.htaccess</context></contextlist>
1531 <override>AuthConfig</override>
1533 <p>Equivalent to <code>SSLCipherSuite</code>, but for the proxy connection.
1534 Please refer to <directive module="mod_ssl">SSLCipherSuite</directive>
1535 for additional information.</p>
1538 </directivesynopsis>
1540 <name>SSLProxyCACertificatePath</name>
1541 <description>Directory of PEM-encoded CA Certificates for
1542 Remote Server Auth</description>
1543 <syntax>SSLProxyCACertificatePath <em>directory-path</em></syntax>
1544 <contextlist><context>server config</context>
1545 <context>virtual host</context></contextlist>
1549 This directive sets the directory where you keep the Certificates of
1550 Certification Authorities (CAs) whose remote servers you deal with. These are used to
1551 verify the remote server certificate on Remote Server Authentication.</p>
1553 The files in this directory have to be PEM-encoded and are accessed through
1554 hash filenames. So usually you can't just place the Certificate files
1555 there: you also have to create symbolic links named
1556 <em>hash-value</em><code>.N</code>. And you should always make sure this directory
1557 contains the appropriate symbolic links. Use the <code>Makefile</code> which
1558 comes with mod_ssl to accomplish this task.</p>
1559 <example><title>Example</title>
1560 SSLProxyCACertificatePath /usr/local/apache2/conf/ssl.crt/
1563 </directivesynopsis>
1566 <name>SSLProxyCACertificateFile</name>
1567 <description>File of concatenated PEM-encoded CA Certificates
1568 for Remote Server Auth</description>
1569 <syntax>SSLProxyCACertificateFile <em>file-path</em></syntax>
1570 <contextlist><context>server config</context>
1571 <context>virtual host</context></contextlist>
1575 This directive sets the <em>all-in-one</em> file where you can assemble the
1576 Certificates of Certification Authorities (CA) whose <em>remote servers</em> you deal
1577 with. These are used for Remote Server Authentication. Such a file is simply the
1578 concatenation of the various PEM-encoded Certificate files, in order of
1579 preference. This can be used alternatively and/or additionally to
1580 <directive module="mod_ssl">SSLProxyCACertificatePath</directive>.</p>
1581 <example><title>Example</title>
1582 SSLProxyCACertificateFile /usr/local/apache2/conf/ssl.crt/ca-bundle-remote-server.crt
1585 </directivesynopsis>
1588 <name>SSLProxyCARevocationPath</name>
1589 <description>Directory of PEM-encoded CA CRLs for
1590 Remote Server Auth</description>
1591 <syntax>SSLProxyCARevocationPath <em>directory-path</em></syntax>
1592 <contextlist><context>server config</context>
1593 <context>virtual host</context></contextlist>
1597 This directive sets the directory where you keep the Certificate Revocation
1598 Lists (CRL) of Certification Authorities (CAs) whose remote servers you deal with.
1599 These are used to revoke the remote server certificate on Remote Server Authentication.</p>
1601 The files in this directory have to be PEM-encoded and are accessed through
1602 hash filenames. So usually you have not only to place the CRL files there.
1603 Additionally you have to create symbolic links named
1604 <em>hash-value</em><code>.rN</code>. And you should always make sure this directory
1605 contains the appropriate symbolic links. Use the <code>Makefile</code> which
1606 comes with <module>mod_ssl</module> to accomplish this task.</p>
1607 <example><title>Example</title>
1608 SSLProxyCARevocationPath /usr/local/apache2/conf/ssl.crl/
1611 </directivesynopsis>
1614 <name>SSLProxyCARevocationFile</name>
1615 <description>File of concatenated PEM-encoded CA CRLs for
1616 Remote Server Auth</description>
1617 <syntax>SSLProxyCARevocationFile <em>file-path</em></syntax>
1618 <contextlist><context>server config</context>
1619 <context>virtual host</context></contextlist>
1623 This directive sets the <em>all-in-one</em> file where you can
1624 assemble the Certificate Revocation Lists (CRL) of Certification
1625 Authorities (CA) whose <em>remote servers</em> you deal with. These are used
1626 for Remote Server Authentication. Such a file is simply the concatenation of
1627 the various PEM-encoded CRL files, in order of preference. This can be
1628 used alternatively and/or additionally to <directive
1629 module="mod_ssl">SSLProxyCARevocationPath</directive>.</p>
1630 <example><title>Example</title>
1631 SSLProxyCARevocationFile /usr/local/apache2/conf/ssl.crl/ca-bundle-remote-server.crl
1634 </directivesynopsis>
1637 <name>SSLUserName</name>
1638 <description>Variable name to determine user name</description>
1639 <syntax>SSLUserName <em>varname</em></syntax>
1640 <contextlist><context>server config</context>
1641 <context>directory</context>
1642 <context>.htaccess</context></contextlist>
1643 <override>AuthConfig</override>
1644 <compatibility>Available in Apache 2.0.51 and later</compatibility>
1648 This directive sets the "user" field in the Apache request object.
1649 This is used by lower modules to identify the user with a character
1650 string. In particular, this may cause the environment variable
1651 <code>REMOTE_USER</code> to be set. The <em>varname</em> can be
1652 any of the <a href="#envvars">SSL environment variables</a>.</p>
1654 <p>Note that this directive has no effect if the
1655 <code>FakeBasic</code> option is used (see <a
1656 href="#ssloptions">SSLOptions</a>).</p>
1658 <example><title>Example</title>
1659 SSLUserName SSL_CLIENT_S_DN_CN
1662 </directivesynopsis>
1665 <name>SSLHonorCipherOrder</name>
1666 <description>Option to prefer the server's cipher preference order</description>
1667 <syntax>SSLHonorCiperOrder <em>flag</em></syntax>
1668 <contextlist><context>server config</context>
1669 <context>virtual host</context></contextlist>
1670 <compatibility>Available in Apache 2.1 and later, if using OpenSSL 0.9.7 or later</compatibility>
1673 <p>When choosing a cipher during an SSLv3 or TLSv1 handshake, normally
1674 the client's preference is used. If this directive is enabled, the
1675 server's preference will be used instead.</p>
1676 <example><title>Example</title>
1677 SSLHonorCipherOrder on
1680 </directivesynopsis>
1683 <name>SSLCryptoDevice</name>
1684 <description>Enable use of a cryptographic hardware accelerator</description>
1685 <syntax>SSLCryptoDevice <em>engine</em></syntax>
1686 <default>SSLCryptoDevice builtin</default>
1687 <contextlist><context>server config</context></contextlist>
1688 <compatibility>Available if mod_ssl is built using <code>-DSSL_ENGINE_EXPERIMENTAL</code></compatibility>
1692 This directive enables use of a cryptographic hardware accelerator
1693 board to offload some of the SSL processing overhead. This directive
1694 can only be used if the SSL toolkit is built with "engine" support;
1695 OpenSSL 0.9.7 and later releases have "engine" support by default, the
1696 separate "-engine" releases of OpenSSL 0.9.6 must be used.</p>
1698 <p>To discover which engine names are supported, run the command
1699 "<code>openssl engine</code>".</p>
1701 <example><title>Example</title>
1702 # For a Broadcom accelerator:<br />
1703 SSLCryptoDevice ubsec
1706 </directivesynopsis>