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| <modulesynopsis metafile="mod_auth_digest.xml.meta"> |
| |
| <name>mod_auth_digest</name> |
| <description>User authentication using MD5 |
| Digest Authentication</description> |
| <status>Extension</status> |
| <sourcefile>mod_auth_digest.c</sourcefile> |
| <identifier>auth_digest_module</identifier> |
| |
| <summary> |
| <p>This module implements HTTP Digest Authentication |
| (<a href="http://www.faqs.org/rfcs/rfc2617.html">RFC2617</a>), and |
| provides an alternative to <module>mod_auth_basic</module> where the |
| password is not transmitted as cleartext. However, this does |
| <strong>not</strong> lead to a significant security advantage over |
| basic authentication. On the other hand, the password storage on the |
| server is much less secure with digest authentication than with |
| basic authentication. Therefore, using basic auth and encrypting the |
| whole connection using <module>mod_ssl</module> is a much better |
| alternative.</p> |
| </summary> |
| |
| <seealso><directive module="mod_authn_core">AuthName</directive></seealso> |
| <seealso><directive module="mod_authn_core">AuthType</directive></seealso> |
| <seealso><directive module="mod_authz_core">Require</directive></seealso> |
| <seealso><a href="../howto/auth.html">Authentication howto</a></seealso> |
| |
| <section id="using"><title>Using Digest Authentication</title> |
| |
| <p>To use MD5 Digest authentication, configure the location to be |
| protected as shown in the below example:</p> |
| |
| <example><title>Example:</title> |
| <highlight language="config"> |
| <Location "/private/"> |
| AuthType Digest |
| AuthName "private area" |
| AuthDigestDomain "/private/" "http://mirror.my.dom/private2/" |
| |
| AuthDigestProvider file |
| AuthUserFile "/web/auth/.digest_pw" |
| Require valid-user |
| </Location> |
| </highlight> |
| </example> |
| |
| <p><directive module="mod_auth_digest">AuthDigestDomain</directive> |
| should list the locations that will be protected by this |
| configuration.</p> |
| |
| <p>The pasword file referenced in the <directive |
| module="mod_auth_digest">AuthUserFile</directive> directive may be |
| created and managed using the <program>htdigest</program> tool.</p> |
| |
| |
| <note><title>Note</title> |
| <p>Digest authentication was intended to be more secure than basic |
| authentication, but no longer fulfills that design goal. A |
| man-in-the-middle attacker can trivially force the browser to downgrade |
| to basic authentication. And even a passive eavesdropper can brute-force |
| the password using today's graphics hardware, because the hashing |
| algorithm used by digest authentication is too fast. Another problem is |
| that the storage of the passwords on the server is insecure. The contents |
| of a stolen htdigest file can be used directly for digest authentication. |
| Therefore using <module>mod_ssl</module> to encrypt the whole connection is |
| strongly recommended.</p> |
| <p><module>mod_auth_digest</module> only works properly on platforms |
| where APR supports shared memory.</p> |
| </note> |
| </section> |
| |
| |
| <directivesynopsis> |
| <name>AuthDigestProvider</name> |
| <description>Sets the authentication provider(s) for this location</description> |
| <syntax>AuthDigestProvider <var>provider-name</var> |
| [<var>provider-name</var>] ...</syntax> |
| <default>AuthDigestProvider file</default> |
| <contextlist><context>directory</context><context>.htaccess</context> |
| </contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p>The <directive>AuthDigestProvider</directive> directive sets |
| which provider is used to authenticate the users for this location. |
| The default <code>file</code> provider is implemented |
| by the <module>mod_authn_file</module> module. Make sure |
| that the chosen provider module is present in the server.</p> |
| |
| <p>See <module>mod_authn_dbm</module>, <module>mod_authn_file</module>, |
| <module>mod_authn_dbd</module> and <module>mod_authn_socache</module> |
| for providers.</p> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>AuthDigestQop</name> |
| <description>Determines the quality-of-protection to use in digest |
| authentication</description> |
| <syntax>AuthDigestQop none|auth|auth-int [auth|auth-int]</syntax> |
| <default>AuthDigestQop auth</default> |
| <contextlist><context>directory</context><context>.htaccess</context> |
| </contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p>The <directive>AuthDigestQop</directive> directive determines |
| the <dfn>quality-of-protection</dfn> to use. <code>auth</code> will |
| only do authentication (username/password); <code>auth-int</code> is |
| authentication plus integrity checking (an MD5 hash of the entity |
| is also computed and checked); <code>none</code> will cause the module |
| to use the old RFC-2069 digest algorithm (which does not include |
| integrity checking). Both <code>auth</code> and <code>auth-int</code> may |
| be specified, in which the case the browser will choose which of |
| these to use. <code>none</code> should only be used if the browser for |
| some reason does not like the challenge it receives otherwise.</p> |
| |
| <note> |
| <code>auth-int</code> is not implemented yet. |
| </note> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>AuthDigestNonceLifetime</name> |
| <description>How long the server nonce is valid</description> |
| <syntax>AuthDigestNonceLifetime <var>seconds</var></syntax> |
| <default>AuthDigestNonceLifetime 300</default> |
| <contextlist><context>directory</context><context>.htaccess</context> |
| </contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p>The <directive>AuthDigestNonceLifetime</directive> directive |
| controls how long the server nonce is valid. When the client |
| contacts the server using an expired nonce the server will send |
| back a 401 with <code>stale=true</code>. If <var>seconds</var> is |
| greater than 0 then it specifies the amount of time for which the |
| nonce is valid; this should probably never be set to less than 10 |
| seconds. If <var>seconds</var> is less than 0 then the nonce never |
| expires. <!-- Not implemented yet: If <var>seconds</var> is 0 then |
| the nonce may be used exactly once by the client. Note that while |
| one-time-nonces provide higher security against replay attacks, |
| they also have significant performance implications, as the |
| browser cannot pipeline or multiple connections for the |
| requests. Because browsers cannot easily detect that |
| one-time-nonces are being used, this may lead to browsers trying |
| to pipeline requests and receiving 401 responses for all but the |
| first request, requiring the browser to resend the requests. Note |
| also that the protection against replay attacks only makes sense |
| for dynamically generated content and things like POST requests; |
| for static content the attacker may already have the complete |
| response, so one-time-nonces do not make sense here. --> |
| </p> |
| </usage> |
| </directivesynopsis> |
| |
| |
| <directivesynopsis> |
| <name>AuthDigestAlgorithm</name> |
| <description>Selects the algorithm used to calculate the challenge and |
| response hashes in digest authentication</description> |
| <syntax>AuthDigestAlgorithm MD5|MD5-sess</syntax> |
| <default>AuthDigestAlgorithm MD5</default> |
| <contextlist><context>directory</context><context>.htaccess</context> |
| </contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p>The <directive>AuthDigestAlgorithm</directive> directive |
| selects the algorithm used to calculate the challenge and response |
| hashes.</p> |
| |
| <note> |
| <code>MD5-sess</code> is not correctly implemented yet. |
| </note> |
| <!-- |
| <p>To use <code>MD5-sess</code> you must first code up the |
| <code>get_userpw_hash()</code> function in |
| <code>mod_auth_digest.c</code>.</p> |
| --> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>AuthDigestDomain</name> |
| <description>URIs that are in the same protection space for digest |
| authentication</description> |
| <syntax>AuthDigestDomain <var>URI</var> [<var>URI</var>] ...</syntax> |
| <contextlist><context>directory</context><context>.htaccess</context> |
| </contextlist> |
| <override>AuthConfig</override> |
| |
| <usage> |
| <p>The <directive>AuthDigestDomain</directive> directive allows |
| you to specify one or more URIs which are in the same protection |
| space (<em>i.e.</em> use the same realm and username/password info). |
| The specified URIs are prefixes; the client will assume |
| that all URIs "below" these are also protected by the same |
| username/password. The URIs may be either absolute URIs (<em>i.e.</em> |
| including a scheme, host, port, etc.) or relative URIs.</p> |
| |
| <p>This directive <em>should</em> always be specified and |
| contain at least the (set of) root URI(s) for this space. |
| Omitting to do so will cause the client to send the |
| Authorization header for <em>every request</em> sent to this |
| server.</p> |
| |
| <p>The URIs specified can also point to different servers, in |
| which case clients (which understand this) will then share |
| username/password info across multiple servers without |
| prompting the user each time. </p> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>AuthDigestShmemSize</name> |
| <description>The amount of shared memory to allocate for keeping track |
| of clients</description> |
| <syntax>AuthDigestShmemSize <var>size</var></syntax> |
| <default>AuthDigestShmemSize 1000</default> |
| <contextlist><context>server config</context></contextlist> |
| |
| <usage> |
| <p>The <directive>AuthDigestShmemSize</directive> directive defines |
| the amount of shared memory, that will be allocated at the server |
| startup for keeping track of clients. Note that the shared memory |
| segment cannot be set less than the space that is necessary for |
| tracking at least <em>one</em> client. This value is dependent on your |
| system. If you want to find out the exact value, you may simply |
| set <directive>AuthDigestShmemSize</directive> to the value of |
| <code>0</code> and read the error message after trying to start the |
| server.</p> |
| |
| <p>The <var>size</var> is normally expressed in Bytes, but you |
| may follow the number with a <code>K</code> or an <code>M</code> to |
| express your value as KBytes or MBytes. For example, the following |
| directives are all equivalent:</p> |
| |
| <highlight language="config"> |
| AuthDigestShmemSize 1048576 |
| AuthDigestShmemSize 1024K |
| AuthDigestShmemSize 1M |
| </highlight> |
| </usage> |
| </directivesynopsis> |
| |
| </modulesynopsis> |