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<modulesynopsis metafile="mod_dav.xml.meta">

<name>mod_dav</name>

<description>Distributed Authoring and Versioning

(<a href="http://www.webdav.org/">WebDAV</a>) functionality</description>

<status>Extension</status>

<sourcefile>mod_dav.c</sourcefile>

<identifier>dav_module</identifier>

<summary>

<p>This module provides class 1 and class 2 <a

href="http://www.webdav.org">WebDAV</a> ('Web-based Distributed

Authoring and Versioning') functionality for Apache. This

extension to the HTTP protocol allows creating, moving,

copying, and deleting resources and collections on a remote web

server.</p>

</summary>

<seealso><directive module="mod_dav_fs">DavLockDB</directive></seealso>

<seealso><directive module="core">LimitXMLRequestBody</directive></seealso>

<seealso><a href="http://www.webdav.org">WebDAV Resources</a></seealso>

<section id="example"><title>Enabling WebDAV</title>

<p>To enable <module>mod_dav</module>, add the following to a

container in your <code>httpd.conf</code> file:</p>

<example>Dav On</example>

<p>This enables the DAV file system provider, which is implemented

by the <module>mod_dav_fs</module> module. Therefore, that module

must be compiled into the server or loaded at runtime using the

<directive module="mod_so">LoadModule</directive> directive.</p>

<p>In addition, a location for the DAV lock database must be

specified in the global section of your <code>httpd.conf</code>

file using the <directive module="mod_dav_fs">DavLockDB</directive>

directive:</p>

<example>

DavLockDB /usr/local/apache2/var/DavLock

</example>

<p>The directory containing the lock database file must be

writable by the <directive module="mod_unixd">User</directive>

and <directive module="mod_unixd" >Group</directive> under which

Apache is running.</p>

<p>You may wish to add a <directive module="core" type="section"

>Limit</directive> clause inside the <directive module="core"

type="section">Location</directive> directive to limit access to

DAV-enabled locations. If you want to set the maximum amount of

bytes that a DAV client can send at one request, you have to use

the <directive module="core">LimitXMLRequestBody</directive>

directive. The "normal" <directive module="core"

>LimitRequestBody</directive> directive has no effect on DAV

requests.</p>

<example><title>Full Example</title>

DavLockDB /usr/local/apache2/var/DavLock<br />

<br />

&lt;Directory /usr/local/apache2/htdocs/foo&gt;<br />

<indent>

Require all granted<br />

Dav On<br />

<br />

AuthType Basic<br />

AuthName DAV<br />

AuthUserFile user.passwd<br />

<br />

&lt;LimitExcept GET POST OPTIONS&gt;<br />

<indent>

Require user admin<br />

</indent>

&lt;/LimitExcept&gt;<br />

</indent>

&lt;/Directory&gt;<br />

</example>

<p><module>mod_dav</module> is a descendent of Greg Stein's <a

href="http://www.webdav.org/mod_dav/">mod_dav for Apache 1.3</a>. More

information about the module is available from that site.</p>

</section>

<section id="security"><title>Security Issues</title>

<p>Since DAV access methods allow remote clients to manipulate

files on the server, you must take particular care to assure that

your server is secure before enabling <module>mod_dav</module>.</p>

<p>Any location on the server where DAV is enabled should be

protected by authentication. The use of HTTP Basic Authentication

is not recommended. You should use at least HTTP Digest

Authentication, which is provided by the

<module>mod_auth_digest</module> module. Nearly all WebDAV clients

support this authentication method. An alternative is Basic

Authentication over an <a href="/ssl/">SSL</a> enabled

connection.</p>

<p>In order for <module>mod_dav</module> to manage files, it must

be able to write to the directories and files under its control

using the <directive module="mod_unixd">User</directive> and

<directive module="mod_unixd">Group</directive> under which

Apache is running. New files created will also be owned by this

<directive module="mod_unixd">User</directive> and <directive

module="mod_unixd">Group</directive>. For this reason, it is

important to control access to this account. The DAV repository

is considered private to Apache; modifying files outside of Apache

(for example using FTP or filesystem-level tools) should not be

allowed.</p>

<p><module>mod_dav</module> may be subject to various kinds of

denial-of-service attacks. The <directive

module="core">LimitXMLRequestBody</directive> directive can be

used to limit the amount of memory consumed in parsing large DAV

requests. The <directive

module="mod_dav">DavDepthInfinity</directive> directive can be

used to prevent <code>PROPFIND</code> requests on a very large

repository from consuming large amounts of memory. Another

possible denial-of-service attack involves a client simply filling

up all available disk space with many large files. There is no

direct way to prevent this in Apache, so you should avoid giving

DAV access to untrusted users.</p>

</section>

<section id="complex"><title>Complex Configurations</title>

<p>One common request is to use <module>mod_dav</module> to

manipulate dynamic files (PHP scripts, CGI scripts, etc). This is

difficult because a <code>GET</code> request will always run the

script, rather than downloading its contents. One way to avoid

this is to map two different URLs to the content, one of which

will run the script, and one of which will allow it to be

downloaded and manipulated with DAV.</p>

<example>

Alias /phparea /home/gstein/php_files<br />

Alias /php-source /home/gstein/php_files<br />

&lt;Location /php-source&gt;

<indent>

DAV On<br />

ForceType text/plain<br />

</indent>

&lt;/Location&gt;

</example>

<p>With this setup, <code>http://example.com/phparea</code> can be

used to access the output of the PHP scripts, and

<code>http://example.com/php-source</code> can be used with a DAV

client to manipulate them.</p>

</section>

<directivesynopsis>

<name>Dav</name>

<description>Enable WebDAV HTTP methods</description>

<syntax>Dav On|Off|<var>provider-name</var></syntax>

<default>Dav Off</default>

<contextlist><context>directory</context></contextlist>

<usage>

<p>Use the <directive>Dav</directive> directive to enable the

WebDAV HTTP methods for the given container:</p>

<example>

&lt;Location /foo&gt;<br />

<indent>

Dav On<br />

</indent>

&lt;/Location&gt;

</example>

<p>The value <code>On</code> is actually an alias for the default

provider <code>filesystem</code> which is served by the <module

>mod_dav_fs</module> module. Note, that once you have DAV enabled

for some location, it <em>cannot</em> be disabled for sublocations.

For a complete configuration example have a look at the <a

href="#example">section above</a>.</p>

<note type="warning">

Do not enable WebDAV until you have secured your server. Otherwise

everyone will be able to distribute files on your system.

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>DavMinTimeout</name>

<description>Minimum amount of time the server holds a lock on

a DAV resource</description>

<syntax>DavMinTimeout <var>seconds</var></syntax>

<default>DavMinTimeout 0</default>

<contextlist><context>server config</context><context>virtual host</context>

<context>directory</context></contextlist>

<usage>

<p>When a client requests a DAV resource lock, it can also

specify a time when the lock will be automatically removed by

the server. This value is only a request, and the server can

ignore it or inform the client of an arbitrary value.</p>

<p>Use the <directive>DavMinTimeout</directive> directive to specify, in

seconds, the minimum lock timeout to return to a client.

Microsoft Web Folders defaults to a timeout of 120 seconds; the

<directive>DavMinTimeout</directive> can override this to a higher value

(like 600 seconds) to reduce the chance of the client losing

the lock due to network latency.</p>

<example><title>Example</title>

&lt;Location /MSWord&gt;<br />

<indent>

DavMinTimeout 600<br />

</indent>

&lt;/Location&gt;

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>DavDepthInfinity</name>

<description>Allow PROPFIND, Depth: Infinity requests</description>

<syntax>DavDepthInfinity on|off</syntax>

<default>DavDepthInfinity off</default>

<contextlist><context>server config</context><context>virtual host</context>

<context>directory</context></contextlist>

<usage>

<p>Use the <directive>DavDepthInfinity</directive> directive to

allow the processing of <code>PROPFIND</code> requests containing the

header 'Depth: Infinity'. Because this type of request could constitute

a denial-of-service attack, by default it is not allowed.</p>

</usage>

</directivesynopsis>

</modulesynopsis>