mod_gridsite - Grid extensions to Apache httpd

Author

       Andrew McNab <Andrew.McNab@manchester.ac.uk>

       mod_gridsite is part of GridSite: http://www.gridsite.org/

Description

mod_gridsite  is  an  Apache  2.0 module which enforces access control via Grid Access Control Lists, and
       X.509, GSI or VOMS credentials. mod_gridsite also gives Apache built-in support  for  the  HTTP  PUT  and
       DELETE methods, and formatting of HTML pages with standard headers and footers.

       Since  mod_gridsite  access  control within Apache itself, Grid authorization and the associated verified
       credentials are available to all technologies supported by Apache, including static  file  serving,  SSI,
       CGI, PHP, mod_perl and Java servlets via a connector to Tomcat.

       Operation  of  mod_gridsite  can  be  configured using runtime directives in Apache's standard httpd.conf
       configuration file. The module must first be loaded with a LoadModule directive:

       LoadModule gridsite_module /PATH/TO/MODULES/mod_gridsite.so

       The module's behaviour is then  controlled  by  GridSite...  directives  within  Apache  <Directory  ...>
       sections, allowing different directories to use GridSite features in different ways.

Directives

GridSiteIndexes on|off
Determines whether GridSite generates HTML directory listings. These have some advantages over
standard Apache directory listings (eg the displayed filenames are never truncated) and will
include standard headers and footers if GridSiteHtmlFormat is on. (Default: GridSiteIndexes off)

GridSiteIndexHeader file
If the named file is found in the directory being listed, the file is included verbatim at the top
of the listing and excluded from the file-by-file listing. The file can either be HTML or plain
text (in which case browsers will be treat it as one HTML paragraph.) (Default: none)

GridSiteHtmlFormat on|off
Determines where HTML pages receive additional formatting before being sent to the client. This
includes the "Last modified", "View page history", "Switch to HTTP(S)", "Print View" and "Built
with GridSite" footer elements. If header and footer files are found, they will be used too.
(Default: GridSiteHtmlFormat off)

GridSiteHeadFile file

GridSiteFootFile file
Set the filenames to be used for as standard headers and footers for HTML pages. If the file name
begins with "/" then this is used as the absolute path to that file to be used. Otherwise, for
each HTML page, the directory of that page is tried first, and then parent directories in
ascending order until a header / footer file is found. Header files are inserted in place of HTML
<body[ ...]> tags; footer files in place of </body>. (These standard files should each include the
appropriate body tag as a replacement.) (Defaults: GridSiteHeadFile gridsitehead.txt,
GridSiteFootFile gridsitefoot.txt)

GridSiteAuth on|off
Enables GridSite access control features, using GACL files. The files are named .gacl and are per-
directory. The current directory is tried and then parent directories in ascending order until a
.gacl file is found. (Default: GridSiteAuth off)

GridSiteAutoPasscode on|off
Whether to automatically issue passcodes in response to HTTPS requests made using a full X.509
certificate (not a GSI proxy.) (Default: GridSiteAutoPasscode on)

GridSiteRequirePasscode on|off
Whether to require passcode cookies when processing HTTPS requests made using a full X.509
certificate (not a GSI proxy.) (Default: GridSiteRequirePasscode off)

GridSiteZoneSlashes number
How many slashes to include in passcode paths. The path is the prefix of REQUEST_URI that includes
that number of slashes. Path matching is checked by mod_gridsite in addition to any selection of
cookies by path made by the browser. (Default: GridSiteZoneSlashes 1)

GridSiteAdminList uri
All members of the DN List with name "uri" receive the full set of permissions, irrespective of
per-directory .gacl files. People in this group have full control over the whole site. (Default:
none)

GridSiteGSIProxyLimit limit
When using GSI Proxy credentials, proxies with delegation depth greater than "limit" will be
ignored by mod_gridsite authorization decisions. A limit of zero implies only full X.509
certificates (and no proxies) will be accepted. A limit of 1 implies that only the initial proxy,
usually created on the user's own machine, is acceptable. Higher levels lead to proxies on remote
machines, eg used by running jobs, being accepted. (Default: GridSiteGSIProxyLimit 1)

GridSiteMethods [GET] [PUT] [DELETE] [MOVE]
Specifies which HTTP methods are supported by GridSite. GET (and HEAD) are always supported. PUT
and DELETE support is turned on by this directive, subject to a positive statement that write
permission is allowed for the directory in question, by a GACL file. (Default: GridSite GET)

GridSiteDNlists directory1[:directory2[:directory3]...]
Sets up the DN List path used by GACL for evaluating <dn-list> credentials. If this directive is
not used, then GACL will use the GRST_DN_LISTS variable from Apache's own environment. If that is
not set either, then /etc/grid-security/dn-lists is searched. (Default: none)

GridSiteDNlistsURI uri
If GridSiteDNlistsURI is used, then the URI given appears to be populated with all the DN lists on
the current DN lists path which match the current server. That is, for server https://example.org/
with DN lists URI /dn-lists/, all DN lists with URLs starting https://example.org/dn-lists/ will
appear to be present in /dn-lists/, irrespective of where in the path they are stored. (Default:
none) <p>

GridSiteAdminURI uri
GridSiteAdminURI gives the absolute URI on the server of the GridSite Admin CGI program, which is
used for file management, HTML and GACL editing. This should be used in conjunction with the
standard Apache directive ScriptAlias to map that URI to the real-gridsite-admin.cgi executable.
For example:

ScriptAlias /real-gridsite-admin.cgi /PATH/TO/real-gridsite-admin.cgi

This URI is always reached by an internal redirection from the value set by GridSiteAdminFile, and
is never visible to users. (Default: none)

GridSiteAdminFile cgifilename
If GridSiteAdminURI is set, then the cgifilename of GridSiteAdminFile appears to be present in all
directories when explicitly requested (it does not appear in directory listings.) Requests for
these ghost CGI URIs are internally redirected to the value set by GridSiteAdminURI. (Default:
GridSiteAdminFile gridsite-admin.cgi)

GridSiteEnvs on|off
This makes mod_gridsite export several variables into the environment of CGI programs and other
dynamic content systems. The variable names are listed below. For gridsite-admin.cgi mechanism to
work, this switch must be left in its default state of on. (Default: GridSiteEnvs on)

GridSiteEditable [ext1 [ext2 [ext3] ...]]]
A space-separated list of file extensions which can safely be edited by the GridSite Text/HTML
editor. The extensions are given without the initial dot. This directive must apply to the
gridsite-admin.cgi executable, rather than just to the files it manages. This is most easily
achieved by placing GridSiteEditable in the main section of the virtual host, outside any
Directory or Location containers. (Default: GridSiteEditable txt shtml html htm css js php jsp)

GridSiteHelpURI uri
If set, gives the URI to use for "Website Help" links in HTML page footers. (Default: none)

GridSiteLoginURI uri
If set, gives the URI prefix to use for login/logout links in page footers. The text
"Login/Logout" will be a link to the prefix followed by the value of REQUEST_URI for the page in
question. (Default: none)

GridSiteLink on|off
Turns off the link in the HTML page footers which gives credit to GridSite. (Default:
GridSiteLink on)

GridSiteUnzip path
If "path" is set by this directive, then real-gridsite-admin.cgi will offer to list the contents
of .zip archives on the server. Users with write access are able to unpack the contents into the
same directory as the .zip file. The value of &quot;path&quot; must point to the location of the
unzip binary. (Default: none)

GridSiteGridHTTP on|off
Enable GridHTTP for this server, virtual server or directory: HTTPS requests made with the header
Upgrade:GridHTTP/1.0 will be redirected to an HTTP version of the file. (Default: off)

GridSiteGridHTTPport port
Sets the port to use for the unencrypted HTTP component of GridHTTP HTTPS->HTTP transfers. The
same setting will be used for all virtual hosts which support GridHTTP. (Default: 777)

GridSiteSessionsDir path
Location of authentication cookies and SSL session credentials directory, relative to ServerRoot.
Used by GridHTTP to record the credentials obtained via HTTPS, and available to the corresponding
HTTP request or subsequent HTTPS requests following a session restart. (Default:
/var/www/sessions)

GridSiteACLFormat GACL|XACML
Format to use when writing .gacl files. (Both formats are automatically recognised when reading.)
(Default: GACL)

GridSiteACLPath path
Specify the absolute or relative (to ServerRoot) path of the ACL file governing this section of
the server's URL space. This can be applied to virtual URL spaces provided by other modules, such
as DAV or SVN, using the Apache <Location> container. If the path contains %0, it is replaced by
this virtual server's hostname. If it contains %1, %2, ... it is replaced with the 1st, 2nd, ...
component of the request's URI, separated by slashes and counting from immediately after the
initial slash.

GridSiteExecMethod nosetuid|suexec|X509DN|directory
Execution strategy for CGI scripts and executables. For options other than nosetuid, suexec (or
gsexec renamed suexec) must installed. For X509DN and directory, gsexec must be installed, as
suexec. See gsexec(8) for an explanation of the different execution strategies. (Default:
nosetuid)

GridSiteUserGroup user group
Unix user and group when using suexec (or gsexec as suexec.) This is equivalent to the suexec
SuexecUserGroup directive, but can be specified on a per-directory basis. (Default: none)

GridSiteDiskMode GroupNone|GroupRead|GroupWrite WorldNone|WorldRead
The file creation permissions mode, taking two arguments to specify the group and other
permissions. The mode always includes read and write permission for the CGI user itself.
(Default: GroupNone WorldNone)

GridSiteCastUniPort port
The UDP unicast port to listen on for HTCP queries, and from which to send replies to HTCP unicast
and multicast queries. Ideally, this should be a privileged port below 1024. This directive may
not appear within a virtual server. (Default: 777)

GridSiteCastGroup group[:port]
A UDP multicast group on which to listen for HTCP queries, plus an optional port. If no port is
given, then 777 is used. Multiple GridSiteCastGroup directives can be given to cause the UDP
responder to listen to more than one multicast group. This directive may not appear within a
virtual server.

GridSiteCastAlias URL-prefix path-prefix
Maps SiteCast generic URLs to the local filesystem. When processing HTCP queries, matching
SiteCast URLs will have URL-prefix stripped off and the remaining portion of the URL added to
path-prefix to construct a local path and filename. If a file is found with that name, a SiteCast
HTCP response will be returned to the querying host. Otherwise the queries are ignored. This
directive may appear within virtual servers, and the virtual server's servername and first port
will determine the host and port name used to construct the transfer URL.

Environment

The following variables are present in the environment of CGI programs and other dynamic content systems
if the GridSiteEnvson directive is in effect.

GRST_PERM
Numerical value of the permission bit-map obtained by comparing the user with the GACL in force.
(These should be tested using the GRSTgaclPermHasXXXX functions from GACL.)

GRST_PASSCODE_COOKIE
Value of GRIDHTTP_PASSCODE cookie that should be returned when using a double-submit cookie
procedure to guard against Cross Site Request Forgery (CSRF) attacks. This is only set if a valid
passcode file was found in the server's sessions directory.

GRST_ADMIN_LIST
URI of the DN List, listing people with full admin and write access to the whole site.

GRST_GSIPROXY_LIMIT
Maximum valid delegation level for GSI Proxies.

GRST_DIR_PATH
Absolute path in the local filesystem to the directory holding the file being requested.

GRST_DESTINATION_TRANSLATED
Present if a WebDAV Destination: header was given in the request with a local URL. Contains the
translation of the URL given into an absolute path in the local filesystem.

GRST_HELP_URI
URI of website help pages set by GridSiteHelpURI directive.

GRST_ADMIN_FILE
Filename of per-directory ghost gridsite-admin.cgi program. (This is used by real-gridsite-
admin.cgi to construct links in its pages.)

GRST_EDITABLE
Space-separated list of extensions which can safely be edited with a Text/HTML editor.

GRST_HEAD_FILE and GRST_FOOT_FILE
Filenames of standard header and footer files.

GRST_DN_LISTS
DN lists search path.

GRST_DN_LISTS_URI
Directory of virtual URIs used to publish this site's DN Lists.

GRST_UNZIP
Full path to the unzip(1) binary, used to list and unpack .zip files.

GRST_NO_LINK
If set, do not include credit links to GridSite in page footers.

GRST_ACL_FORMAT
Format to use when writing .gacl files: either GACL or XACML.

GRST_EXEC_METHOD
Specified by GridSiteExecMethod either suexec, X509DN or directory.

GRST_EXEC_DIRECTORY
The directory containing the CGI script or executable (used by gsexec to determine which pool
account to use in directory mapping mode.)

GRST_DISK_MODE
The Apache disk permission modes bit pattern, in hexadecimal, starting with 0x. (Similar to the
Unix bit pattern, except with hexadecimal rather than octal values: eg 0x600 [Apache] vs 0600
[Unix] are both read/write for user only.)

Name

mod_gridsite - Grid extensions to Apache httpd

Synopsis

LoadModulegridsite_modulemod_gridsite.so