| <?xml version="1.0"?> |
| <!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd"> |
| <?xml-stylesheet type="text/xsl" href="../style/manual.xsl"?> |
| <modulesynopsis> |
| |
| <name>mod_ssl</name> |
| <description>Strong cryptography using the Secure Sockets |
| Layer (SSL) and Transport Layer Security (TLS) protocols</description> |
| <status>Extension</status> |
| <sourcefile>mod_ssl.c</sourcefile> |
| <identifier>ssl_module</identifier> |
| |
| <summary> |
| <p>This module provides SSL v2/v3 and TLS v1 support for the Apache |
| HTTP Server. It was contributed by Ralf S. Engeschall based on his |
| mod_ssl project and originally derived from work by Ben Laurie.</p> |
| |
| <p>This module relies on <a href="http://www.openssl.org/">OpenSSL</a> |
| to provide the cryptography engine.</p> |
| |
| <p>Further details, discussion, and examples are provided in the |
| <a href="../ssl/">SSL documentation</a>.</p> |
| </summary> |
| |
| <section id="ToC25"><title>Environment Variables</title> |
| |
| <p>This module provides a lot of SSL information as additional environment |
| variables to the SSI and CGI namespace. The generated variables are listed in |
| the table below. For backward compatibility the information can |
| be made available under different names, too. Look in the <a |
| href="../ssl/ssl_compat.html">Compatibility</a> chapter for details on the |
| compatibility variables.</p> |
| |
| <div align="center"> |
| <a name="table4"></a> |
| <table width="600" cellspacing="0" cellpadding="1" border="0" summary=""> |
| <caption align="bottom" id="sf">SSI/CGI Environment Variables</caption> |
| <tr><td bgcolor="#cccccc"> |
| <table width="598" cellpadding="5" cellspacing="0" border="0" summary=""> |
| <tr><td valign="top" align="center" bgcolor="#ffffff"> |
| <table border="0" cellspacing="0" cellpadding="2" width="598" summary=""> |
| <tr id="H"> |
| <td><strong>Variable Name:</strong></td> |
| <td><strong>Value Type:</strong></td> |
| <td><strong>Description:</strong></td> |
| </tr> |
| <tr id="D"><td><code>HTTPS</code></td> <td>flag</td> <td>HTTPS is being used.</td></tr> |
| <tr id="H"><td><code>SSL_PROTOCOL</code></td> <td>string</td> <td>The SSL protocol version (SSLv2, SSLv3, TLSv1)</td></tr> |
| <tr id="H"><td><code>SSL_SESSION_ID</code></td> <td>string</td> <td>The hex-encoded SSL session id</td></tr> |
| <tr id="D"><td><code>SSL_CIPHER</code></td> <td>string</td> <td>The cipher specification name</td></tr> |
| <tr id="D"><td><code>SSL_CIPHER_EXPORT</code></td> <td>string</td> <td><code>true</code> if cipher is an export cipher</td></tr> |
| <tr id="H"><td><code>SSL_CIPHER_USEKEYSIZE</code></td> <td>number</td> <td>Number of cipher bits (actually used)</td></tr> |
| <tr id="D"><td><code>SSL_CIPHER_ALGKEYSIZE</code></td> <td>number</td> <td>Number of cipher bits (possible)</td></tr> |
| <tr id="H"><td><code>SSL_VERSION_INTERFACE</code></td> <td>string</td> <td>The mod_ssl program version</td></tr> |
| <tr id="D"><td><code>SSL_VERSION_LIBRARY</code></td> <td>string</td> <td>The OpenSSL program version</td></tr> |
| <tr id="H"><td><code>SSL_CLIENT_M_VERSION</code></td> <td>string</td> <td>The version of the client certificate</td></tr> |
| <tr id="D"><td><code>SSL_CLIENT_M_SERIAL</code></td> <td>string</td> <td>The serial of the client certificate</td></tr> |
| <tr id="H"><td><code>SSL_CLIENT_S_DN</code></td> <td>string</td> <td>Subject DN in client's certificate</td></tr> |
| <tr id="D"><td><code>SSL_CLIENT_S_DN_</code><em>x509</em></td> <td>string</td> <td>Component of client's Subject DN</td></tr> |
| <tr id="H"><td><code>SSL_CLIENT_I_DN</code></td> <td>string</td> <td>Issuer DN of client's certificate</td></tr> |
| <tr id="D"><td><code>SSL_CLIENT_I_DN_</code><em>x509</em></td> <td>string</td> <td>Component of client's Issuer DN</td></tr> |
| <tr id="H"><td><code>SSL_CLIENT_V_START</code></td> <td>string</td> <td>Validity of client's certificate (start time)</td></tr> |
| <tr id="D"><td><code>SSL_CLIENT_V_END</code></td> <td>string</td> <td>Validity of client's certificate (end time)</td></tr> |
| <tr id="H"><td><code>SSL_CLIENT_A_SIG</code></td> <td>string</td> <td>Algorithm used for the signature of client's certificate</td></tr> |
| <tr id="D"><td><code>SSL_CLIENT_A_KEY</code></td> <td>string</td> <td>Algorithm used for the public key of client's certificate</td></tr> |
| <tr id="H"><td><code>SSL_CLIENT_CERT</code></td> <td>string</td> <td>PEM-encoded client certificate</td></tr> |
| <tr id="D"><td><code>SSL_CLIENT_CERT_CHAIN</code><em>n</em></td> <td>string</td> <td>PEM-encoded certificates in client certificate chain</td></tr> |
| <tr id="H"><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> |
| <tr id="D"><td><code>SSL_SERVER_M_VERSION</code></td> <td>string</td> <td>The version of the server certificate</td></tr> |
| <tr id="H"><td><code>SSL_SERVER_M_SERIAL</code></td> <td>string</td> <td>The serial of the server certificate</td></tr> |
| <tr id="D"><td><code>SSL_SERVER_S_DN</code></td> <td>string</td> <td>Subject DN in server's certificate</td></tr> |
| <tr id="H"><td><code>SSL_SERVER_S_DN_</code><em>x509</em></td> <td>string</td> <td>Component of server's Subject DN</td></tr> |
| <tr id="D"><td><code>SSL_SERVER_I_DN</code></td> <td>string</td> <td>Issuer DN of server's certificate</td></tr> |
| <tr id="H"><td><code>SSL_SERVER_I_DN_</code><em>x509</em></td> <td>string</td> <td>Component of server's Issuer DN</td></tr> |
| <tr id="D"><td><code>SSL_SERVER_V_START</code></td> <td>string</td> <td>Validity of server's certificate (start time)</td></tr> |
| <tr id="H"><td><code>SSL_SERVER_V_END</code></td> <td>string</td> <td>Validity of server's certificate (end time)</td></tr> |
| <tr id="D"><td><code>SSL_SERVER_A_SIG</code></td> <td>string</td> <td>Algorithm used for the signature of server's certificate</td></tr> |
| <tr id="H"><td><code>SSL_SERVER_A_KEY</code></td> <td>string</td> <td>Algorithm used for the public key of server's certificate</td></tr> |
| <tr id="D"><td><code>SSL_SERVER_CERT</code></td> <td>string</td> <td>PEM-encoded server certificate</td></tr> |
| </table> |
| [ where <em>x509</em> is a component of a X.509 DN: |
| <code>C,ST,L,O,OU,CN,T,I,G,S,D,UID,Email</code> ] |
| </td> |
| </tr></table> |
| </td></tr></table> |
| </div> |
| </section> |
| |
| <section id="ToC26"><title>Custom Log Formats</title> |
| |
| <p>When <module>mod_ssl</module> is built into Apache or at least |
| loaded (under DSO situation) additional functions exist for the <a |
| href="../mod_log_config.html#formats">Custom Log Format</a> of |
| <module>mod_log_config</module>. First there is an |
| additional ``<code>%{</code><em>varname</em><code>}x</code>'' |
| eXtension format function which can be used to expand any variables |
| provided by any module, especially those provided by mod_ssl which can |
| you find in the above table.</p> |
| <p> |
| For backward compatibility there is additionally a special |
| ``<code>%{</code><em>name</em><code>}c</code>'' cryptography format function |
| provided. Information about this function is provided in the <a |
| href="../ssl/ssl_compat.html">Compatibility</a> chapter.</p> |
| <p> |
| Example:</p> |
| <example> |
| CustomLog logs/ssl_request_log \ |
| "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b" |
| </example> |
| </section> |
| |
| <directivesynopsis> |
| <name>SSLPassPhraseDialog</name> |
| <description>Type of pass phrase dialog for encrypted private |
| keys</description> |
| <syntax>SSLPassPhraseDialog <em>type</em></syntax> |
| <default>SSLPassPhraseDialog builtin</default> |
| <contextlist><context>server config</context></contextlist> |
| |
| <usage> |
| <p> |
| When Apache starts up it has to read the various Certificate (see |
| <directive module="mod_ssl">SSLCertificateFile</directive>) and |
| Private Key (see <directive |
| module="mod_ssl">SSLCertificateKeyFile</directive>) files of the |
| SSL-enabled virtual servers. Because for security reasons the Private |
| Key files are usually encrypted, mod_ssl needs to query the |
| administrator for a Pass Phrase in order to decrypt those files. This |
| query can be done in two ways which can be configured by |
| <em>type</em>:</p> |
| <ul> |
| <li><code>builtin</code> |
| <p> |
| This is the default where an interactive terminal dialog occurs at startup |
| time just before Apache detaches from the terminal. Here the administrator |
| has to manually enter the Pass Phrase for each encrypted Private Key file. |
| Because a lot of SSL-enabled virtual hosts can be configured, the |
| following reuse-scheme is used to minimize the dialog: When a Private Key |
| file is encrypted, all known Pass Phrases (at the beginning there are |
| none, of course) are tried. If one of those known Pass Phrases succeeds no |
| dialog pops up for this particular Private Key file. If none succeeded, |
| another Pass Phrase is queried on the terminal and remembered for the next |
| round (where it perhaps can be reused).</p> |
| <p> |
| This scheme allows mod_ssl to be maximally flexible (because for N encrypted |
| Private Key files you <em>can</em> use N different Pass Phrases - but then |
| you have to enter all of them, of course) while minimizing the terminal |
| dialog (i.e. when you use a single Pass Phrase for all N Private Key files |
| this Pass Phrase is queried only once).</p></li> |
| |
| <li><code>exec:/path/to/program</code> |
| <p> |
| Here an external program is configured which is called at startup for each |
| encrypted Private Key file. It is called with two arguments (the first is |
| of the form ``<code>servername:portnumber</code>'', the second is either |
| ``<code>RSA</code>'' or ``<code>DSA</code>''), which indicate for which |
| server and algorithm it has to print the corresponding Pass Phrase to |
| <code>stdout</code>. The intent is that this external program first runs |
| security checks to make sure that the system is not compromised by an |
| attacker, and only when these checks were passed successfully it provides |
| the Pass Phrase.</p> |
| <p> |
| Both these security checks, and the way the Pass Phrase is determined, can |
| be as complex as you like. Mod_ssl just defines the interface: an |
| executable program which provides the Pass Phrase on <code>stdout</code>. |
| Nothing more or less! So, if you're really paranoid about security, here |
| is your interface. Anything else has to be left as an exercise to the |
| administrator, because local security requirements are so different.</p> |
| <p> |
| The reuse-algorithm above is used here, too. In other words: The external |
| program is called only once per unique Pass Phrase.</p></li> |
| </ul> |
| <p> |
| Example:</p> |
| <example> |
| SSLPassPhraseDialog exec:/usr/local/apache/sbin/pp-filter |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLMutex</name> |
| <description>Semaphore for internal mutual exclusion of |
| operations</description> |
| <syntax>SSLMutex <em>type</em></syntax> |
| <default>SSLMutex none</default> |
| <contextlist><context>server config</context></contextlist> |
| |
| <usage> |
| <p> |
| This configures the SSL engine's semaphore (aka. lock) which is used for mutual |
| exclusion of operations which have to be done in a synchronized way between the |
| pre-forked Apache server processes. This directive can only be used in the |
| global server context because it's only useful to have one global mutex.</p> |
| <p> |
| The following Mutex <em>types</em> are available:</p> |
| <ul> |
| <li><code>none</code> |
| <p> |
| This is the default where no Mutex is used at all. Use it at your own |
| risk. But because currently the Mutex is mainly used for synchronizing |
| write access to the SSL Session Cache you can live without it as long |
| as you accept a sometimes garbled Session Cache. So it's not recommended |
| to leave this the default. Instead configure a real Mutex.</p></li> |
| <li><code>file:/path/to/mutex</code> |
| <p> |
| This is the portable and (under Unix) always provided Mutex variant where |
| a physical (lock-)file is used as the Mutex. Always use a local disk |
| filesystem for <code>/path/to/mutex</code> and never a file residing on a |
| NFS- or AFS-filesystem. Note: Internally, the Process ID (PID) of the |
| Apache parent process is automatically appended to |
| <code>/path/to/mutex</code> to make it unique, so you don't have to worry |
| about conflicts yourself. Notice that this type of mutex is not available |
| under the Win32 environment. There you <em>have</em> to use the semaphore |
| mutex.</p></li> |
| <li><code>sem</code> |
| <p> |
| This is the most elegant but also most non-portable Mutex variant where a |
| SysV IPC Semaphore (under Unix) and a Windows Mutex (under Win32) is used |
| when possible. It is only available when the underlying platform |
| supports it.</p></li> |
| </ul> |
| <example><title>Example</title> |
| SSLMutex file:/usr/local/apache/logs/ssl_mutex |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLRandomSeed</name> |
| <description>Pseudo Random Number Generator (PRNG) seeding |
| source</description> |
| <syntax>SSLRandomSeed <em>context</em> <em>source</em> |
| [<em>bytes</em>]</syntax> |
| <contextlist><context>server config</context></contextlist> |
| |
| <usage> |
| <p> |
| This configures one or more sources for seeding the Pseudo Random Number |
| Generator (PRNG) in OpenSSL at startup time (<em>context</em> is |
| <code>startup</code>) and/or just before a new SSL connection is established |
| (<em>context</em> is <code>connect</code>). This directive can only be used |
| in the global server context because the PRNG is a global facility.</p> |
| <p> |
| The following <em>source</em> variants are available:</p> |
| <ul> |
| <li><code>builtin</code> |
| <p> This is the always available builtin seeding source. It's usage |
| consumes minimum CPU cycles under runtime and hence can be always used |
| without drawbacks. The source used for seeding the PRNG contains of the |
| current time, the current process id and (when applicable) a randomly |
| choosen 1KB extract of the inter-process scoreboard structure of Apache. |
| The drawback is that this is not really a strong source and at startup |
| time (where the scoreboard is still not available) this source just |
| produces a few bytes of entropy. So you should always, at least for the |
| startup, use an additional seeding source.</p></li> |
| <li><code>file:/path/to/source</code> |
| <p> |
| This variant uses an external file <code>/path/to/source</code> as the |
| source for seeding the PRNG. When <em>bytes</em> is specified, only the |
| first <em>bytes</em> number of bytes of the file form the entropy (and |
| <em>bytes</em> is given to <code>/path/to/source</code> as the first |
| argument). When <em>bytes</em> is not specified the whole file forms the |
| entropy (and <code>0</code> is given to <code>/path/to/source</code> as |
| the first argument). Use this especially at startup time, for instance |
| with an available <code>/dev/random</code> and/or |
| <code>/dev/urandom</code> devices (which usually exist on modern Unix |
| derivates like FreeBSD and Linux).</p> |
| <p> |
| <em>But be careful</em>: Usually <code>/dev/random</code> provides only as |
| much entropy data as it actually has, i.e. when you request 512 bytes of |
| entropy, but the device currently has only 100 bytes available two things |
| can happen: On some platforms you receive only the 100 bytes while on |
| other platforms the read blocks until enough bytes are available (which |
| can take a long time). Here using an existing <code>/dev/urandom</code> is |
| better, because it never blocks and actually gives the amount of requested |
| data. The drawback is just that the quality of the received data may not |
| be the best.</p> |
| <p> |
| On some platforms like FreeBSD one can even control how the entropy is |
| actually generated, i.e. by which system interrupts. More details one can |
| find under <em>rndcontrol(8)</em> on those platforms. Alternatively, when |
| your system lacks such a random device, you can use tool |
| like <a href="http://www.lothar.com/tech/crypto/">EGD</a> |
| (Entropy Gathering Daemon) and run it's client program with the |
| <code>exec:/path/to/program/</code> variant (see below) or use |
| <code>egd:/path/to/egd-socket</code> (see below).</p></li> |
| |
| <li><code>exec:/path/to/program</code> |
| <p> |
| This variant uses an external executable |
| <code>/path/to/program</code> as the source for seeding the |
| PRNG. When <em>bytes</em> is specified, only the first |
| <em>bytes</em> number of bytes of its <code>stdout</code> contents |
| form the entropy. When <em>bytes</em> is not specified, the |
| entirety of the data produced on <code>stdout</code> form the |
| entropy. Use this only at startup time when you need a very strong |
| seeding with the help of an external program (for instance as in |
| the example above with the <code>truerand</code> utility you can |
| find in the mod_ssl distribution which is based on the AT&T |
| <em>truerand</em> library). Using this in the connection context |
| slows down the server too dramatically, of course. So usually you |
| should avoid using external programs in that context.</p></li> |
| <li><code>egd:/path/to/egd-socket</code> (Unix only) |
| <p> |
| This variant uses the Unix domain socket of the |
| external Entropy Gathering Daemon (EGD) (see <a |
| href="http://www.lothar.com/tech/crypto/">http://www.lothar.com/tech |
| /crypto/</a>) to seed the PRNG. Use this if no random device exists |
| on your platform.</p></li> |
| </ul> |
| <example><title>Example</title> |
| SSLRandomSeed startup builtin<br /> |
| SSLRandomSeed startup file:/dev/random<br /> |
| SSLRandomSeed startup file:/dev/urandom 1024<br /> |
| SSLRandomSeed startup exec:/usr/local/bin/truerand 16<br /> |
| SSLRandomSeed connect builtin<br /> |
| SSLRandomSeed connect file:/dev/random<br /> |
| SSLRandomSeed connect file:/dev/urandom 1024<br /> |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLSessionCache</name> |
| <description>Type of the global/inter-process SSL Session |
| Cache</description> |
| <syntax>SSLSessionCache <em>type</em></syntax> |
| <default>SSLSessionCache none</default> |
| <contextlist><context>server config</context></contextlist> |
| |
| <usage> |
| <p> |
| This configures the storage type of the global/inter-process SSL Session |
| Cache. This cache is an optional facility which speeds up parallel request |
| processing. For requests to the same server process (via HTTP keep-alive), |
| OpenSSL already caches the SSL session information locally. But because modern |
| clients request inlined images and other data via parallel requests (usually |
| up to four parallel requests are common) those requests are served by |
| <em>different</em> pre-forked server processes. Here an inter-process cache |
| helps to avoid unneccessary session handshakes.</p> |
| <p> |
| The following two storage <em>type</em>s are currently supported:</p> |
| <ul> |
| <li><code>none</code> |
| <p> |
| This is the default and just disables the global/inter-process Session |
| Cache. There is no drawback in functionality, but a noticeable speed |
| penalty can be observed.</p></li> |
| <li><code>dbm:/path/to/datafile</code> |
| <p> |
| This makes use of a DBM hashfile on the local disk to synchronize the |
| local OpenSSL memory caches of the server processes. The slight increase |
| in I/O on the server results in a visible request speedup for your |
| clients, so this type of storage is generally recommended.</p></li> |
| <li><code>shm:/path/to/datafile</code>[<code>(</code><em>size</em><code>)</code>] |
| <p> |
| This makes use of a high-performance hash table (approx. <em>size</em> bytes |
| in size) inside a shared memory segment in RAM (established via |
| <code>/path/to/datafile</code>) to synchronize the local OpenSSL memory |
| caches of the server processes. This storage type is not available on all |
| platforms. See the mod_ssl <code>INSTALL</code> document for details on |
| how to build Apache+EAPI with shared memory support.</p></li> |
| </ul> |
| <example><title>Examples</title> |
| SSLSessionCache dbm:/usr/local/apache/logs/ssl_gcache_data<br /> |
| SSLSessionCache shm:/usr/local/apache/logs/ssl_gcache_data(512000) |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLSessionCacheTimeout</name> |
| <description>Number of seconds before an SSL session expires |
| in the Session Cache</description> |
| <syntax>SSLSessionCacheTimeout <em>seconds</em></syntax> |
| <default>SSLSessionCacheTimeout 300</default> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive sets the timeout in seconds for the information stored in the |
| global/inter-process SSL Session Cache and the OpenSSL internal memory cache. |
| It can be set as low as 15 for testing, but should be set to higher |
| values like 300 in real life.</p> |
| <example><title>Example</title> |
| SSLSessionCacheTimeout 600 |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLEngine</name> |
| <description>SSL Engine Operation Switch</description> |
| <syntax>SSLEngine on|off</syntax> |
| <default>SSLEngine off</default> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive toggles the usage of the SSL/TLS Protocol Engine. This |
| is usually used inside a <directive module="core" |
| type="section">VirtualHost</directive> section to enable SSL/TLS for a |
| particular virtual host. By default the SSL/TLS Protocol Engine is |
| disabled for both the main server and all configured virtual hosts.</p> |
| <example><title>Example</title> |
| <VirtualHost _default_:443><br /> |
| SSLEngine on<br /> |
| ...<br /> |
| </VirtualHost> |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLProtocol</name> |
| <description>Configure usable SSL protocol flavors</description> |
| <syntax>SSLProtocol [+|-]<em>protocol</em> ...</syntax> |
| <default>SSLProtocol all</default> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| <override>Options</override> |
| |
| <usage><!-- XXX Why does this have an override and not .htaccess context? --> |
| <p> |
| This directive can be used to control the SSL protocol flavors mod_ssl should |
| use when establishing its server environment. Clients then can only connect |
| with one of the provided protocols.</p> |
| <p> |
| The available (case-insensitive) <em>protocol</em>s are:</p> |
| <ul> |
| <li><code>SSLv2</code> |
| <p> |
| This is the Secure Sockets Layer (SSL) protocol, version 2.0. It is the |
| original SSL protocol as designed by Netscape Corporation.</p></li> |
| |
| <li><code>SSLv3</code> |
| <p> |
| This is the Secure Sockets Layer (SSL) protocol, version 3.0. It is the |
| successor to SSLv2 and the currently (as of February 1999) de-facto |
| standardized SSL protocol from Netscape Corporation. It's supported by |
| almost all popular browsers.</p></li> |
| |
| <li><code>TLSv1</code> |
| <p> |
| This is the Transport Layer Security (TLS) protocol, version 1.0. It is the |
| successor to SSLv3 and currently (as of February 1999) still under |
| construction by the Internet Engineering Task Force (IETF). It's still |
| not supported by any popular browsers.</p></li> |
| |
| <li><code>All</code> |
| <p> |
| This is a shortcut for ``<code>+SSLv2 +SSLv3 +TLSv1</code>'' and a |
| convinient way for enabling all protocols except one when used in |
| combination with the minus sign on a protocol as the example above |
| shows.</p></li> |
| </ul> |
| <example><title>Example</title> |
| # enable SSLv3 and TLSv1, but not SSLv2<br /> |
| SSLProtocol all -SSLv2 |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLCipherSuite</name> |
| <description>Cipher Suite available for negotiation in SSL |
| handshake</description> |
| <syntax>SSLCipherSuite <em>cipher-spec</em></syntax> |
| <default>SSLCipherSuite ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP</default> |
| <contextlist><context>server config</context> |
| <context>virtual host</context> |
| <context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p> |
| This complex directive uses a colon-separated <em>cipher-spec</em> string |
| consisting of OpenSSL cipher specifications to configure the Cipher Suite the |
| client is permitted to negotiate in the SSL handshake phase. Notice that this |
| directive can be used both in per-server and per-directory context. In |
| per-server context it applies to the standard SSL handshake when a connection |
| is established. In per-directory context it forces a SSL renegotation with the |
| reconfigured Cipher Suite after the HTTP request was read but before the HTTP |
| response is sent.</p> |
| <p> |
| An SSL cipher specification in <em>cipher-spec</em> is composed of 4 major |
| attributes plus a few extra minor ones:</p> |
| <ul> |
| <li><em>Key Exchange Algorithm</em>:<br /> |
| RSA or Diffie-Hellman variants. |
| </li> |
| <li><em>Authentication Algorithm</em>:<br /> |
| RSA, Diffie-Hellman, DSS or none. |
| </li> |
| <li><em>Cipher/Encryption Algorithm</em>:<br /> |
| DES, Triple-DES, RC4, RC2, IDEA or none. |
| </li> |
| <li><em>MAC Digest Algorithm</em>:<br /> |
| MD5, SHA or SHA1. |
| </li> |
| </ul> |
| <p>An SSL cipher can also be an export cipher and is either a SSLv2 or SSLv3/TLSv1 |
| cipher (here TLSv1 is equivalent to SSLv3). To specify which ciphers to use, |
| one can either specify all the Ciphers, one at a time, or use aliases to |
| specify the preference and order for the ciphers (see <a href="#table1">Table |
| 1</a>).</p> |
| |
| <div align="center"> |
| <a name="table1"></a> |
| <table width="600" cellspacing="0" cellpadding="1" border="0" summary=""> |
| <caption align="bottom" id="sf">Table 1: OpenSSL Cipher Specification Tags</caption> |
| <tr><td bgcolor="#cccccc"> |
| <table width="598" cellpadding="5" cellspacing="0" border="0" summary=""> |
| <tr><td valign="top" align="center" bgcolor="#ffffff"> |
| <table border="0" cellspacing="0" cellpadding="2" width="598" summary=""> |
| <tr id="D"><td><strong>Tag</strong></td> <td><strong>Description</strong></td></tr> |
| <tr id="H"><td colspan="2"><em>Key Exchange Algorithm:</em></td></tr> |
| <tr id="D"><td><code>kRSA</code></td> <td>RSA key exchange</td></tr> |
| <tr id="H"><td><code>kDHr</code></td> <td>Diffie-Hellman key exchange with RSA key</td></tr> |
| <tr id="D"><td><code>kDHd</code></td> <td>Diffie-Hellman key exchange with DSA key</td></tr> |
| <tr id="H"><td><code>kEDH</code></td> <td>Ephemeral (temp.key) Diffie-Hellman key exchange (no cert)</td> </tr> |
| <tr id="H"><td colspan="2"><em>Authentication Algorithm:</em></td></tr> |
| <tr id="D"><td><code>aNULL</code></td> <td>No authentication</td></tr> |
| <tr id="H"><td><code>aRSA</code></td> <td>RSA authentication</td></tr> |
| <tr id="D"><td><code>aDSS</code></td> <td>DSS authentication</td> </tr> |
| <tr id="H"><td><code>aDH</code></td> <td>Diffie-Hellman authentication</td></tr> |
| <tr id="D"><td colspan="2"><em>Cipher Encoding Algorithm:</em></td></tr> |
| <tr id="H"><td><code>eNULL</code></td> <td>No encoding</td> </tr> |
| <tr id="D"><td><code>DES</code></td> <td>DES encoding</td> </tr> |
| <tr id="H"><td><code>3DES</code></td> <td>Triple-DES encoding</td> </tr> |
| <tr id="D"><td><code>RC4</code></td> <td>RC4 encoding</td> </tr> |
| <tr id="H"><td><code>RC2</code></td> <td>RC2 encoding</td> </tr> |
| <tr id="D"><td><code>IDEA</code></td> <td>IDEA encoding</td> </tr> |
| <tr id="H"><td colspan="2"><em>MAC Digest Algorithm</em>:</td></tr> |
| <tr id="D"><td><code>MD5</code></td> <td>MD5 hash function</td></tr> |
| <tr id="H"><td><code>SHA1</code></td> <td>SHA1 hash function</td></tr> |
| <tr id="D"><td><code>SHA</code></td> <td>SHA hash function</td> </tr> |
| <tr id="H"><td colspan="2"><em>Aliases:</em></td></tr> |
| <tr id="D"><td><code>SSLv2</code></td> <td>all SSL version 2.0 ciphers</td></tr> |
| <tr id="H"><td><code>SSLv3</code></td> <td>all SSL version 3.0 ciphers</td> </tr> |
| <tr id="D"><td><code>TLSv1</code></td> <td>all TLS version 1.0 ciphers</td> </tr> |
| <tr id="H"><td><code>EXP</code></td> <td>all export ciphers</td> </tr> |
| <tr id="D"><td><code>EXPORT40</code></td> <td>all 40-bit export ciphers only</td> </tr> |
| <tr id="H"><td><code>EXPORT56</code></td> <td>all 56-bit export ciphers only</td> </tr> |
| <tr id="D"><td><code>LOW</code></td> <td>all low strength ciphers (no export, single DES)</td></tr> |
| <tr id="H"><td><code>MEDIUM</code></td> <td>all ciphers with 128 bit encryption</td> </tr> |
| <tr id="D"><td><code>HIGH</code></td> <td>all ciphers using Triple-DES</td> </tr> |
| <tr id="H"><td><code>RSA</code></td> <td>all ciphers using RSA key exchange</td> </tr> |
| <tr id="D"><td><code>DH</code></td> <td>all ciphers using Diffie-Hellman key exchange</td> </tr> |
| <tr id="H"><td><code>EDH</code></td> <td>all ciphers using Ephemeral Diffie-Hellman key exchange</td> </tr> |
| <tr id="D"><td><code>ADH</code></td> <td>all ciphers using Anonymous Diffie-Hellman key exchange</td> </tr> |
| <tr id="H"><td><code>DSS</code></td> <td>all ciphers using DSS authentication</td> </tr> |
| <tr id="D"><td><code>NULL</code></td> <td>all ciphers using no encryption</td> </tr> |
| </table> |
| </td> |
| </tr></table> |
| </td></tr></table> |
| </div> |
| <p> |
| Now where this becomes interesting is that these can be put together |
| to specify the order and ciphers you wish to use. To speed this up |
| there are also aliases (<code>SSLv2, SSLv3, TLSv1, EXP, LOW, MEDIUM, |
| HIGH</code>) for certain groups of ciphers. These tags can be joined |
| together with prefixes to form the <em>cipher-spec</em>. Available |
| prefixes are:</p> |
| <ul> |
| <li>none: add cipher to list</li> |
| <li><code>+</code>: add ciphers to list and pull them to current location in list</li> |
| <li><code>-</code>: remove cipher from list (can be added later again)</li> |
| <li><code>!</code>: kill cipher from list completely (can <strong>not</strong> be added later again)</li> |
| </ul> |
| <p>A simpler way to look at all of this is to use the ``<code>openssl ciphers |
| -v</code>'' command which provides a nice way to successively create the |
| correct <em>cipher-spec</em> string. The default <em>cipher-spec</em> string |
| is ``<code>ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP</code>'' which |
| means the following: first, remove from consideration any ciphers that do not |
| authenticate, i.e. for SSL only the Anonymous Diffie-Hellman ciphers. Next, |
| use ciphers using RC4 and RSA. Next include the high, medium and then the low |
| security ciphers. Finally <em>pull</em> all SSLv2 and export ciphers to the |
| end of the list.</p> |
| <example> |
| <pre> |
| $ openssl ciphers -v 'ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP' |
| NULL-SHA SSLv3 Kx=RSA Au=RSA Enc=None Mac=SHA1 |
| NULL-MD5 SSLv3 Kx=RSA Au=RSA Enc=None Mac=MD5 |
| EDH-RSA-DES-CBC3-SHA SSLv3 Kx=DH Au=RSA Enc=3DES(168) Mac=SHA1 |
| ... ... ... ... ... |
| EXP-RC4-MD5 SSLv3 Kx=RSA(512) Au=RSA Enc=RC4(40) Mac=MD5 export |
| EXP-RC2-CBC-MD5 SSLv2 Kx=RSA(512) Au=RSA Enc=RC2(40) Mac=MD5 export |
| EXP-RC4-MD5 SSLv2 Kx=RSA(512) Au=RSA Enc=RC4(40) Mac=MD5 export |
| </pre> |
| </example> |
| <p>The complete list of particular RSA & DH ciphers for SSL is given in <a |
| href="#table2">Table 2</a>.</p> |
| <example><title>Example</title> |
| SSLCipherSuite RSA:!EXP:!NULL:+HIGH:+MEDIUM:-LOW |
| </example> |
| <div align="center"> |
| <a name="table2"></a> |
| <table width="600" cellspacing="0" cellpadding="1" border="0" summary=""> |
| <caption align="bottom" id="sf">Table 2: Particular SSL Ciphers</caption> |
| <tr><td bgcolor="#cccccc"> |
| <table width="598" cellpadding="5" cellspacing="0" border="0" summary=""> |
| <tr><td valign="top" align="center" bgcolor="#ffffff"> |
| <table border="0" cellspacing="0" cellpadding="2" width="598" summary=""> |
| <tr id="D"><td><strong>Cipher-Tag</strong></td> <td><strong>Protocol</strong></td> <td><strong>Key Ex.</strong></td> <td><strong>Auth.</strong></td> <td><strong>Enc.</strong></td> <td><strong>MAC</strong></td> <td><strong>Type</strong></td> </tr> |
| <tr id="H"><td colspan="7"><em>RSA Ciphers:</em></td></tr> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><td><code>NULL-SHA</code></td> <td>SSLv3</td> <td>RSA</td> <td>RSA</td> <td>None</td> <td>SHA1</td> <td> </td> </tr> |
| <tr id="H"><td><code>NULL-MD5</code></td> <td>SSLv3</td> <td>RSA</td> <td>RSA</td> <td>None</td> <td>MD5</td> <td> </td> </tr> |
| <tr id="D"><td colspan="7"><em>Diffie-Hellman Ciphers:</em></td></tr> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| <tr id="D"><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> |
| <tr id="H"><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> |
| </table> |
| </td> |
| </tr></table> |
| </td></tr></table> |
| </div> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLCertificateFile</name> |
| <description>Server PEM-encoded X.509 Certificate file</description> |
| <syntax>SSLCertificateFile <em>file-path</em></syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive points to the PEM-encoded Certificate file for the server and |
| optionally also to the corresponding RSA or DSA Private Key file for it |
| (contained in the same file). If the contained Private Key is encrypted the |
| Pass Phrase dialog is forced at startup time. This directive can be used up to |
| two times (referencing different filenames) when both a RSA and a DSA based |
| server certificate is used in parallel.</p> |
| <example><title>Example</title> |
| SSLCertificateFile /usr/local/apache/conf/ssl.crt/server.crt |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLCertificateKeyFile</name> |
| <description>Server PEM-encoded Private Key file</description> |
| <syntax>SSLCertificateKeyFile <em>file-path</em></syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive points to the PEM-encoded Private Key file for the |
| server. If the Private Key is not combined with the Certificate in the |
| <directive>SSLCertificateFile</directive>, use this additional directive to |
| point to the file with the stand-alone Private Key. When |
| <directive>SSLCertificateFile</directive> is used and the file |
| contains both the Certificate and the Private Key this directive need |
| not be used. But we strongly discourage this practice. Instead we |
| recommend you to separate the Certificate and the Private Key. If the |
| contained Private Key is encrypted, the Pass Phrase dialog is forced |
| at startup time. This directive can be used up to two times |
| (referencing different filenames) when both a RSA and a DSA based |
| private key is used in parallel.</p> |
| <example><title>Example</title> |
| SSLCertificateKeyFile /usr/local/apache/conf/ssl.key/server.key |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLCertificateChainFile</name> |
| <description>File of PEM-encoded Server CA Certificates</description> |
| <syntax>SSLCertificateChainFile <em>file-path</em></syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive sets the optional <em>all-in-one</em> file where you can |
| assemble the certificates of Certification Authorities (CA) which form the |
| certificate chain of the server certificate. This starts with the issuing CA |
| certificate of of the server certificate and can range up to the root CA |
| certificate. Such a file is simply the concatenation of the various |
| PEM-encoded CA Certificate files, usually in certificate chain order.</p> |
| <p> |
| This should be used alternatively and/or additionally to <directive |
| module="mod_ssl">SSLCACertificatePath</directive> for explicitly |
| constructing the server certificate chain which is sent to the browser |
| in addition to the server certificate. It is especially useful to |
| avoid conflicts with CA certificates when using client |
| authentication. Because although placing a CA certificate of the |
| server certificate chain into <directive |
| module="mod_ssl">SSLCACertificatePath</directive> has the same effect |
| for the certificate chain construction, it has the side-effect that |
| client certificates issued by this same CA certificate are also |
| accepted on client authentication. That's usually not one expect.</p> |
| <p> |
| But be careful: Providing the certificate chain works only if you are using a |
| <em>single</em> (either RSA <em>or</em> DSA) based server certificate. If you are |
| using a coupled RSA+DSA certificate pair, this will work only if actually both |
| certificates use the <em>same</em> certificate chain. Else the browsers will be |
| confused in this situation.</p> |
| <example><title>Example</title> |
| SSLCertificateChainFile /usr/local/apache/conf/ssl.crt/ca.crt |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLCACertificatePath</name> |
| <description>Directory of PEM-encoded CA Certificates for |
| Client Auth</description> |
| <syntax>SSLCACertificatePath <em>directory-path</em></syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive sets the directory where you keep the Certificates of |
| Certification Authorities (CAs) whose clients you deal with. These are used to |
| verify the client certificate on Client Authentication.</p> |
| <p> |
| The files in this directory have to be PEM-encoded and are accessed through |
| hash filenames. So usually you can't just place the Certificate files |
| there: you also have to create symbolic links named |
| <em>hash-value</em><code>.N</code>. And you should always make sure this directory |
| contains the appropriate symbolic links. Use the <code>Makefile</code> which |
| comes with mod_ssl to accomplish this task.</p> |
| <example><title>Example</title> |
| SSLCACertificatePath /usr/local/apache/conf/ssl.crt/ |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLCACertificateFile</name> |
| <description>File of concatenated PEM-encoded CA Certificates |
| for Client Auth</description> |
| <syntax>SSLCACertificateFile <em>file-path</em></syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive sets the <em>all-in-one</em> file where you can assemble the |
| Certificates of Certification Authorities (CA) whose <em>clients</em> you deal |
| with. These are used for Client Authentication. Such a file is simply the |
| concatenation of the various PEM-encoded Certificate files, in order of |
| preference. This can be used alternatively and/or additionally to |
| <directive module="mod_ssl">SSLCACertificatePath</directive>.</p> |
| <example><title>Example</title> |
| SSLCACertificateFile /usr/local/apache/conf/ssl.crt/ca-bundle-client.crt |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLCARevocationPath</name> |
| <description>Directory of PEM-encoded CA CRLs for |
| Client Auth</description> |
| <syntax>SSLCARevocationPath <em>directory-path</em></syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive sets the directory where you keep the Certificate Revocation |
| Lists (CRL) of Certification Authorities (CAs) whose clients you deal with. |
| These are used to revoke the client certificate on Client Authentication.</p> |
| <p> |
| The files in this directory have to be PEM-encoded and are accessed through |
| hash filenames. So usually you have not only to place the CRL files there. |
| Additionally you have to create symbolic links named |
| <em>hash-value</em><code>.rN</code>. And you should always make sure this directory |
| contains the appropriate symbolic links. Use the <code>Makefile</code> which |
| comes with <module>mod_ssl</module> to accomplish this task.</p> |
| <example><title>Example</title> |
| SSLCARevocationPath /usr/local/apache/conf/ssl.crl/ |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLCARevocationFile</name> |
| <description>File of concatenated PEM-encoded CA CRLs for |
| Client Auth</description> |
| <syntax>SSLCARevocationFile <em>file-path</em></syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive sets the <em>all-in-one</em> file where you can |
| assemble the Certificate Revocation Lists (CRL) of Certification |
| Authorities (CA) whose <em>clients</em> you deal with. These are used |
| for Client Authentication. Such a file is simply the concatenation of |
| the various PEM-encoded CRL files, in order of preference. This can be |
| used alternatively and/or additionally to <directive |
| module="mod_ssl">SSLCARevocationPath</directive>.</p> |
| <example><title>Example</title> |
| SSLCARevocationFile /usr/local/apache/conf/ssl.crl/ca-bundle-client.crl |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLVerifyClient</name> |
| <description>Type of Client Certificate verification</description> |
| <syntax>SSLVerifyClient <em>level</em></syntax> |
| <default>SSLVerifyClient none</default> |
| <contextlist><context>server config</context> |
| <context>virtual host</context> |
| <context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p> |
| This directive sets the Certificate verification level for the Client |
| Authentication. Notice that this directive can be used both in per-server and |
| per-directory context. In per-server context it applies to the client |
| authentication process used in the standard SSL handshake when a connection is |
| established. In per-directory context it forces a SSL renegotation with the |
| reconfigured client verification level after the HTTP request was read but |
| before the HTTP response is sent.</p> |
| <p> |
| The following levels are available for <em>level</em>:</p> |
| <ul> |
| <li><strong>none</strong>: |
| no client Certificate is required at all</li> |
| <li><strong>optional</strong>: |
| the client <em>may</em> present a valid Certificate</li> |
| <li><strong>require</strong>: |
| the client <em>has to</em> present a valid Certificate</li> |
| <li><strong>optional_no_ca</strong>: |
| the client may present a valid Certificate<br /> |
| but it need not to be (successfully) verifiable.</li> |
| </ul> |
| <p>In practice only levels <strong>none</strong> and |
| <strong>require</strong> are really interesting, because level |
| <strong>optional</strong> doesn't work with all browsers and level |
| <strong>optional_no_ca</strong> is actually against the idea of |
| authentication (but can be used to establish SSL test pages, etc.)</p> |
| <example><title>Example</title> |
| SSLVerifyClient require |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLVerifyDepth</name> |
| <description>Maximum depth of CA Certificates in Client |
| Certificate verification</description> |
| <syntax>SSLVerifyDepth <em>number</em></syntax> |
| <default>SSLVerifyDepth 1</default> |
| <contextlist><context>server config</context> |
| <context>virtual host</context> |
| <context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p> |
| This directive sets how deeply mod_ssl should verify before deciding that the |
| clients don't have a valid certificate. Notice that this directive can be |
| used both in per-server and per-directory context. In per-server context it |
| applies to the client authentication process used in the standard SSL |
| handshake when a connection is established. In per-directory context it forces |
| a SSL renegotation with the reconfigured client verification depth after the |
| HTTP request was read but before the HTTP response is sent.</p> |
| <p> |
| The depth actually is the maximum number of intermediate certificate issuers, |
| i.e. the number of CA certificates which are max allowed to be followed while |
| verifying the client certificate. A depth of 0 means that self-signed client |
| certificates are accepted only, the default depth of 1 means the client |
| certificate can be self-signed or has to be signed by a CA which is directly |
| known to the server (i.e. the CA's certificate is under |
| <directive module="mod_ssl">SSLCACertificatePath</directive>), etc.</p> |
| <example><title>Example</title> |
| SSLVerifyDepth 10 |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLLog</name> |
| <description>Where to write the dedicated SSL engine logfile</description> |
| <syntax>SSLLog <em>file-path</em></syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive sets the name of the dedicated SSL protocol engine logfile. |
| Error type messages are additionally duplicated to the general Apache error |
| log file (directive <code>ErrorLog</code>). Put this somewhere where it cannot |
| be used for symlink attacks on a real server (i.e. somewhere where only root |
| can write). If the <em>file-path</em> does not begin with a slash |
| ('<code>/</code>') then it is assumed to be relative to the <em>Server |
| Root</em>. If <em>file-path</em> begins with a bar ('<code>|</code>') then the |
| following string is assumed to be a path to an executable program to which a |
| reliable pipe can be established. The directive should occur only once per |
| virtual server config.</p> |
| <example><title>Example</title> |
| SSLLog /usr/local/apache/logs/ssl_engine_log |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLLogLevel</name> |
| <description>Logging level for the dedicated SSL engine |
| logfile</description> |
| <syntax>SSLLogLevel <em>level</em></syntax> |
| <default>SSLLogLevel none</default> |
| <contextlist><context>server config</context> |
| <context>virtual host</context></contextlist> |
| |
| <usage> |
| <p> |
| This directive sets the verbosity degree of the dedicated SSL protocol engine |
| logfile. The <em>level</em> is one of the following (in ascending order where |
| higher levels include lower levels):</p> |
| <ul> |
| <li><code>none</code><br /> |
| no dedicated SSL logging is done, but messages of level |
| ``<code>error</code>'' are still written to the general Apache error |
| logfile. |
| </li> |
| <li><code>error</code><br /> |
| log messages of error type only, i.e. messages which show fatal situations |
| (processing is stopped). Those messages are also duplicated to the |
| general Apache error logfile. |
| </li> |
| <li><code>warn</code><br /> |
| log also warning messages, i.e. messages which show non-fatal problems |
| (processing is continued). |
| </li> |
| <li><code>info</code><br /> |
| log also informational messages, i.e. messages which show major |
| processing steps. |
| </li> |
| <li><code>trace</code><br /> |
| log also trace messages, i.e. messages which show minor processing steps. |
| </li> |
| <li><code>debug</code><br /> |
| log also debugging messages, i.e. messages which show development and |
| low-level I/O information. |
| </li> |
| </ul> |
| <example><title>Example</title> |
| SSLLogLevel warn |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLOptions</name> |
| <description>Configure various SSL engine run-time options</description> |
| <syntax>SSLOptions [+|-]<em>option</em> ...</syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context> |
| <context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>Options</override> |
| |
| <usage> |
| <p> |
| This directive can be used to control various run-time options on a |
| per-directory basis. Normally, if multiple <code>SSLOptions</code> |
| could apply to a directory, then the most specific one is taken |
| completely; the options are not merged. However if <em>all</em> the |
| options on the <code>SSLOptions</code> directive are preceded by a |
| plus (<code>+</code>) or minus (<code>-</code>) symbol, the options |
| are merged. Any options preceded by a <code>+</code> are added to the |
| options currently in force, and any options preceded by a |
| <code>-</code> are removed from the options currently in force.</p> |
| <p> |
| The available <em>option</em>s are:</p> |
| <ul> |
| <li><code>StdEnvVars</code> |
| <p> |
| When this option is enabled, the standard set of SSL related CGI/SSI |
| environment variables are created. This per default is disabled for |
| performance reasons, because the information extraction step is a |
| rather expensive operation. So one usually enables this option for |
| CGI and SSI requests only.</p> |
| </li> |
| <li><code>CompatEnvVars</code> |
| <p> |
| When this option is enabled, additional CGI/SSI environment variables are |
| created for backward compatibility to other Apache SSL solutions. Look in |
| the <a href="../ssl/ssl_compat.html">Compatibility</a> chapter for details |
| on the particular variables generated.</p> |
| </li> |
| <li><code>ExportCertData</code> |
| <p> |
| When this option is enabled, additional CGI/SSI environment variables are |
| created: <code>SSL_SERVER_CERT</code>, <code>SSL_CLIENT_CERT</code> and |
| <code>SSL_CLIENT_CERT_CHAIN</code><em>n</em> (with <em>n</em> = 0,1,2,..). |
| These contain the PEM-encoded X.509 Certificates of server and client for |
| the current HTTPS connection and can be used by CGI scripts for deeper |
| Certificate checking. Additionally all other certificates of the client |
| certificate chain are provided, too. This bloats up the environment a |
| little bit which is why you have to use this option to enable it on |
| demand.</p> |
| </li> |
| <li><code>FakeBasicAuth</code> |
| <p> |
| When this option is enabled, the Subject Distinguished Name (DN) of the |
| Client X509 Certificate is translated into a HTTP Basic Authorization |
| username. This means that the standard Apache authentication methods can |
| be used for access control. The user name is just the Subject of the |
| Client's X509 Certificate (can be determined by running OpenSSL's |
| <code>openssl x509</code> command: <code>openssl x509 -noout -subject -in |
| </code><em>certificate</em><code>.crt</code>). Note that no password is |
| obtained from the user. Every entry in the user file needs this password: |
| ``<code>xxj31ZMTZzkVA</code>'', which is the DES-encrypted version of the |
| word `<code>password</code>''. Those who live under MD5-based encryption |
| (for instance under FreeBSD or BSD/OS, etc.) should use the following MD5 |
| hash of the same word: ``<code>$1$OXLyS...$Owx8s2/m9/gfkcRVXzgoE/</code>''.</p> |
| </li> |
| <li><code>StrictRequire</code> |
| <p> |
| This <em>forces</em> forbidden access when <code>SSLRequireSSL</code> or |
| <code>SSLRequire</code> successfully decided that access should be |
| forbidden. Usually the default is that in the case where a ``<code>Satisfy |
| any</code>'' directive is used, and other access restrictions are passed, |
| denial of access due to <code>SSLRequireSSL</code> or |
| <code>SSLRequire</code> is overridden (because that's how the Apache |
| <code>Satisfy</code> mechanism should work.) But for strict access restriction |
| you can use <code>SSLRequireSSL</code> and/or <code>SSLRequire</code> in |
| combination with an ``<code>SSLOptions +StrictRequire</code>''. Then an |
| additional ``<code>Satisfy Any</code>'' has no chance once mod_ssl has |
| decided to deny access.</p> |
| </li> |
| <li><code>OptRenegotiate</code> |
| <p> |
| This enables optimized SSL connection renegotiation handling when SSL |
| directives are used in per-directory context. By default a strict |
| scheme is enabled where <em>every</em> per-directory reconfiguration of |
| SSL parameters causes a <em>full</em> SSL renegotiation handshake. When this |
| option is used mod_ssl tries to avoid unnecessary handshakes by doing more |
| granular (but still safe) parameter checks. Nevertheless these granular |
| checks sometimes maybe not what the user expects, so enable this on a |
| per-directory basis only, please.</p> |
| </li> |
| </ul> |
| <example><title>Example</title> |
| SSLOptions +FakeBasicAuth -StrictRequire<br /> |
| <Files ~ "\.(cgi|shtml)$"><br /> |
| SSLOptions +StdEnvVars +CompatEnvVars -ExportCertData<br /> |
| <Files> |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLRequireSSL</name> |
| <description>Deny access when SSL is not used for the |
| HTTP request</description> |
| <syntax>SSLRequireSSL</syntax> |
| <contextlist><context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p><!-- XXX: I think the syntax is wrong --> |
| This directive forbids access unless HTTP over SSL (i.e. HTTPS) is enabled for |
| the current connection. This is very handy inside the SSL-enabled virtual |
| host or directories for defending against configuration errors that expose |
| stuff that should be protected. When this directive is present all requests |
| are denied which are not using SSL.</p> |
| <example><title>Example</title> |
| SSLRequireSSL |
| </example> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SSLRequire</name> |
| <description>Allow access only when an arbitrarily complex |
| boolean expression is true</description> |
| <syntax>SSLRequire <em>expression</em></syntax> |
| <contextlist><context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p> |
| This directive specifies a general access requirement which has to be |
| fulfilled in order to allow access. It's a very powerful directive because the |
| requirement specification is an arbitrarily complex boolean expression |
| containing any number of access checks.</p> |
| <p> |
| The <em>expression</em> must match the following syntax (given as a BNF |
| grammar notation):</p> |
| <blockquote> |
| <pre> |
| expr ::= "<strong>true</strong>" | "<strong>false</strong>" |
| | "<strong>!</strong>" expr |
| | expr "<strong>&&</strong>" expr |
| | expr "<strong>||</strong>" expr |
| | "<strong>(</strong>" expr "<strong>)</strong>" |
| | comp |
| |
| comp ::= word "<strong>==</strong>" word | word "<strong>eq</strong>" word |
| | word "<strong>!=</strong>" word | word "<strong>ne</strong>" word |
| | word "<strong><</strong>" word | word "<strong>lt</strong>" word |
| | word "<strong><=</strong>" word | word "<strong>le</strong>" word |
| | word "<strong>></strong>" word | word "<strong>gt</strong>" word |
| | word "<strong>>=</strong>" word | word "<strong>ge</strong>" word |
| | word "<strong>in</strong>" "<strong>{</strong>" wordlist "<strong>}</strong>" |
| | word "<strong>=~</strong>" regex |
| | word "<strong>!~</strong>" regex |
| |
| wordlist ::= word |
| | wordlist "<strong>,</strong>" word |
| |
| word ::= digit |
| | cstring |
| | variable |
| | function |
| |
| digit ::= [0-9]+ |
| cstring ::= "..." |
| variable ::= "<strong>%{</strong>" varname "<strong>}</strong>" |
| function ::= funcname "<strong>(</strong>" funcargs "<strong>)</strong>" |
| </pre> |
| </blockquote> |
| <p>while for <code>varname</code> any variable from <a |
| href="#table3">Table 3</a> can be used. Finally for |
| <code>funcname</code> the following functions are available:</p> |
| <ul> |
| <li><code>file(</code><em>filename</em><code>)</code> |
| <p> |
| This function takes one string argument and expands to the contents of the |
| file. This is especially useful for matching this contents against a |
| regular expression, etc.</p> |
| </li> |
| </ul> |
| <p>Notice that <em>expression</em> is first parsed into an internal machine |
| representation and then evaluated in a second step. Actually, in Global and |
| Per-Server Class context <em>expression</em> is parsed at startup time and |
| at runtime only the machine representation is executed. For Per-Directory |
| context this is different: here <em>expression</em> has to be parsed and |
| immediately executed for every request.</p> |
| <example><title>Example</title> |
| SSLRequire ( %{SSL_CIPHER} !~ m/^(EXP|NULL)-/ \<br /> |
| and %{SSL_CLIENT_S_DN_O} eq "Snake Oil, Ltd." \<br /> |
| and %{SSL_CLIENT_S_DN_OU} in {"Staff", "CA", "Dev"} \<br /> |
| and %{TIME_WDAY} >= 1 and %{TIME_WDAY} <= 5 \<br /> |
| and %{TIME_HOUR} >= 8 and %{TIME_HOUR} <= 20 ) \<br /> |
| or %{REMOTE_ADDR} =~ m/^192\.76\.162\.[0-9]+$/ |
| </example> |
| <div align="center"> |
| <a name="table3"></a> |
| <table width="600" cellspacing="0" cellpadding="1" border="0" summary=""> |
| <caption align="bottom" id="sf">Table 3: Available Variables for SSLRequire</caption> |
| <tr><td bgcolor="#cccccc"> |
| <table width="598" cellpadding="5" cellspacing="0" border="0" summary=""> |
| <tr><td valign="top" align="center" bgcolor="#ffffff"> |
| <table summary=""><tr><td> |
| <em>Standard CGI/1.0 and Apache variables:</em> |
| <pre> |
| HTTP_USER_AGENT PATH_INFO AUTH_TYPE |
| HTTP_REFERER QUERY_STRING SERVER_SOFTWARE |
| HTTP_COOKIE REMOTE_HOST API_VERSION |
| HTTP_FORWARDED REMOTE_IDENT TIME_YEAR |
| HTTP_HOST IS_SUBREQ TIME_MON |
| HTTP_PROXY_CONNECTION DOCUMENT_ROOT TIME_DAY |
| HTTP_ACCEPT SERVER_ADMIN TIME_HOUR |
| HTTP:headername SERVER_NAME TIME_MIN |
| THE_REQUEST SERVER_PORT TIME_SEC |
| REQUEST_METHOD SERVER_PROTOCOL TIME_WDAY |
| REQUEST_SCHEME REMOTE_ADDR TIME |
| REQUEST_URI REMOTE_USER ENV:<strong>variablename</strong> |
| REQUEST_FILENAME |
| </pre> |
| <em>SSL-related variables:</em> |
| <pre> |
| HTTPS SSL_CLIENT_M_VERSION SSL_SERVER_M_VERSION |
| SSL_CLIENT_M_SERIAL SSL_SERVER_M_SERIAL |
| SSL_PROTOCOL SSL_CLIENT_V_START SSL_SERVER_V_START |
| SSL_SESSION_ID SSL_CLIENT_V_END SSL_SERVER_V_END |
| SSL_CIPHER SSL_CLIENT_S_DN SSL_SERVER_S_DN |
| SSL_CIPHER_EXPORT SSL_CLIENT_S_DN_C SSL_SERVER_S_DN_C |
| SSL_CIPHER_ALGKEYSIZE SSL_CLIENT_S_DN_ST SSL_SERVER_S_DN_ST |
| SSL_CIPHER_USEKEYSIZE SSL_CLIENT_S_DN_L SSL_SERVER_S_DN_L |
| SSL_VERSION_LIBRARY SSL_CLIENT_S_DN_O SSL_SERVER_S_DN_O |
| SSL_VERSION_INTERFACE SSL_CLIENT_S_DN_OU SSL_SERVER_S_DN_OU |
| SSL_CLIENT_S_DN_CN SSL_SERVER_S_DN_CN |
| SSL_CLIENT_S_DN_T SSL_SERVER_S_DN_T |
| SSL_CLIENT_S_DN_I SSL_SERVER_S_DN_I |
| SSL_CLIENT_S_DN_G SSL_SERVER_S_DN_G |
| SSL_CLIENT_S_DN_S SSL_SERVER_S_DN_S |
| SSL_CLIENT_S_DN_D SSL_SERVER_S_DN_D |
| SSL_CLIENT_S_DN_UID SSL_SERVER_S_DN_UID |
| SSL_CLIENT_S_DN_Email SSL_SERVER_S_DN_Email |
| SSL_CLIENT_I_DN SSL_SERVER_I_DN |
| SSL_CLIENT_I_DN_C SSL_SERVER_I_DN_C |
| SSL_CLIENT_I_DN_ST SSL_SERVER_I_DN_ST |
| SSL_CLIENT_I_DN_L SSL_SERVER_I_DN_L |
| SSL_CLIENT_I_DN_O SSL_SERVER_I_DN_O |
| SSL_CLIENT_I_DN_OU SSL_SERVER_I_DN_OU |
| SSL_CLIENT_I_DN_CN SSL_SERVER_I_DN_CN |
| SSL_CLIENT_I_DN_T SSL_SERVER_I_DN_T |
| SSL_CLIENT_I_DN_I SSL_SERVER_I_DN_I |
| SSL_CLIENT_I_DN_G SSL_SERVER_I_DN_G |
| SSL_CLIENT_I_DN_S SSL_SERVER_I_DN_S |
| SSL_CLIENT_I_DN_D SSL_SERVER_I_DN_D |
| SSL_CLIENT_I_DN_UID SSL_SERVER_I_DN_UID |
| SSL_CLIENT_I_DN_Email SSL_SERVER_I_DN_Email |
| SSL_CLIENT_A_SIG SSL_SERVER_A_SIG |
| SSL_CLIENT_A_KEY SSL_SERVER_A_KEY |
| SSL_CLIENT_CERT SSL_SERVER_CERT |
| SSL_CLIENT_CERT_CHAIN<strong>n</strong> |
| SSL_CLIENT_VERIFY |
| </pre> |
| </td></tr></table> |
| </td> |
| </tr></table> |
| </td></tr></table> |
| </div> |
| </usage> |
| </directivesynopsis> |
| |
| </modulesynopsis> |