New in Apache HTTP Server 2.4 – Authorization, FCGI Proxy, and Mod_SSL

New Authorization Containers

The authorization container directives <RequireAll>, <RequireAny> and <RequireNone> may be combined with each other and with the Require directive to express complex authorization logic.

The example below expresses the following authorization logic. In order to access the resource, the user must either be the superadmin user, or belong to both the admins group and the Administrators LDAP group and either belong to the sales group or have the LDAP dept attribute sales. Furthermore, in order to access the resource, the user must not belong to either the temps group or the LDAP group Temporary Employees.

<Directory /www/mydocs>

<RequireAll>

<RequireAny>


Require user superadmin
<RequireAll>

Require group admins
Require ldap-group cn=Administrators,o=Airius
<RequireAny>

Require group sales
Require ldap-attribute dept="sales"

</RequireAny>

</RequireAll>

</RequireAny>
<RequireNone>

Require group temps
Require ldap-group cn=Temporary Employees,o=Airius

</RequireNone>


</RequireAll>

</Directory>


This is gonna be BIG! You can read the whole story at http://httpd.apache.org/docs/trunk/new_features_2_4.html

Core Enhancements

KeepAliveTimeout in milliseconds

It is now possible to specify KeepAliveTimeout in milliseconds.

Simple MPM

Cleanroom MPM implementation with advanced thread pool management

Loadable MPMs

Multiple MPMs can now be built as loadable modules at compile time. The MPM of choice can be configured at run time.

Module Enhancements

mod_ssl

mod_ssl can now be configured to use an OCSP server to check the validation status of a client certificate. The default responder is configurable, along with the decision on whether to prefer the responder designated in the client certificate itself.

mod_ssl now also supports OCSP stapling, where the server pro-actively obtains an OCSP verification of its certificate and transmits that to the client during the handshake.

mod_ssl can now be configured to share SSL Session data between servers through memcached

mod_lua

Embeds the Lua language into httpd, for configuration and small business logic functions.

mod_proxy_fcgi

FastCGI Protocol backend for mod_proxy

Program Enhancements

fcgistarter – FastCGI deamon starter utility

Module Developer Changes

Check Configuration Hook Added

A new hook, check_config, has been added which runs between the pre_config and open_logs hooks. It also runs before the test_config hook when the -t option is passed to httpd. The check_config hook allows modules to review interdependent configuration directive values and adjust them while messages can still be logged to the console. The user can thus be alerted to misconfiguration problems before the core open_logs hook function redirects console output to the error log.

Expression Parser Added

We now have a general-purpose expression parser, whose API is exposed in ap_expr.h. This is adapted from the expression parser previously implemented in mod_include.

Authorization Logic Containers

Advanced authorization logic may now be specified using the Require directive and the related container directives, such as <RequireAll>, all provided by the mod_authz_core module.

Small-Object Caching Interface

The ap_socache.h header exposes a provider-based interface for caching small data objects, based on the previous implementation of the mod_ssl session cache. Providers using a shared-memory cyclic buffer, disk-based dbm files, and a memcache distributed cache are currently supported.

Full List of Security / Code Changes

                                                         -*- coding: utf-8 -*-
Changes with Apache 2.2.15

  *) SECURITY: CVE-2009-3555 (cve.mitre.org)
     mod_ssl: Comprehensive fix of the TLS renegotiation prefix injection
     attack when compiled against OpenSSL version 0.9.8m or later. Introduces
     the 'SSLInsecureRenegotiation' directive to reopen this vulnerability
     and offer unsafe legacy renegotiation with clients which do not yet
     support the new secure renegotiation protocol, RFC 5746.
     [Joe Orton, and with thanks to the OpenSSL Team]

  *) SECURITY: CVE-2009-3555 (cve.mitre.org)
     mod_ssl: A partial fix for the TLS renegotiation prefix injection attack
     by rejecting any client-initiated renegotiations. Forcibly disable
     keepalive for the connection if there is any buffered data readable. Any
     configuration which requires renegotiation for per-directory/location
     access control is still vulnerable, unless using OpenSSL >= 0.9.8l.
     [Joe Orton, Ruediger Pluem, Hartmut Keil ]

  *) SECURITY: CVE-2010-0408 (cve.mitre.org)
     mod_proxy_ajp: Respond with HTTP_BAD_REQUEST when the body is not sent
     when request headers indicate a request body is incoming; not a case of
     HTTP_INTERNAL_SERVER_ERROR.  [Niku Toivola ]

  *) SECURITY: CVE-2010-0425 (cve.mitre.org)
     mod_isapi: Do not unload an isapi .dll module until the request
     processing is completed, avoiding orphaned callback pointers.
     [Brett Gervasoni , Jeff Trawick]

  *) SECURITY: CVE-2010-0434 (cve.mitre.org)
     Ensure each subrequest has a shallow copy of headers_in so that the
     parent request headers are not corrupted.  Elimiates a problematic
     optimization in the case of no request body.  PR 48359
     [Jake Scott, William Rowe, Ruediger Pluem]

  *) mod_reqtimeout: New module to set timeouts and minimum data rates for
     receiving requests from the client. [Stefan Fritsch]

  *) mod_proxy_ajp: Really regard the operation a success, when the client
     aborted the connection. In addition adjust the log message if the client
     aborted the connection. [Ruediger Pluem]

  *) mod_negotiation: Preserve query string over multiviews negotiation.
     This buglet was fixed for type maps in 2.2.6, but the same issue
     affected multiviews and was overlooked.
     PR 33112 [Joergen Thomsen ]

  *) mod_cache: Introduce the thundering herd lock, a mechanism to keep
     the flood of requests at bay that strike a backend webserver as
     a cached entity goes stale. [Graham Leggett]

  *) mod_proxy_http: Make sure that when an ErrorDocument is served
     from a reverse proxied URL, that the subrequest respects the status
     of the original request. This brings the behaviour of proxy_handler
     in line with default_handler. PR 47106. [Graham Leggett]

  *) mod_log_config: Add the R option to log the handler used within the
     request. [Christian Folini ]

  *) mod_include: Allow fine control over the removal of Last-Modified and
     ETag headers within the INCLUDES filter, making it possible to cache
     responses if desired. Fix the default value of the SSIAccessEnable
     directive. [Graham Leggett]

  *) mod_ssl: Fix a potential I/O hang if a long list of trusted CAs
     is configured for client cert auth. PR 46952.  [Joe Orton]

  *) core: Fix potential memory leaks by making sure to not destroy
     bucket brigades that have been created by earlier filters.
     [Stefan Fritsch]

  *) mod_authnz_ldap: Add AuthLDAPBindAuthoritative to allow Authentication to
     try other providers in the case of an LDAP bind failure.
     PR 46608 [Justin Erenkrantz, Joe Schaefer, Tony Stevenson]

  *) mod_proxy, mod_proxy_http: Support remote https proxies
     by using HTTP CONNECT.
     PR 19188.  [Philippe Dutrueux , Rainer Jung]

  *) worker: Don't report server has reached MaxClients until it has.
     Add message when server gets within MinSpareThreads of MaxClients.
     PR 46996.  [Dan Poirier]

  *) mod_ssl: When extracting certificate subject/issuer names to the
     SSL_*_DN_* variables, handle RDNs with duplicate tags by
     exporting multiple varialables with an "_n" integer suffix.
     PR 45875.  [Joe Orton, Peter Sylvester ]

  *) mod_authnz_ldap: Failures to map a username to a DN, or to check a user
     password now result in an informational level log entry instead of
     warning level.  [Eric Covener]

  *) core: Preserve Port information over internal redirects
     PR 35999 [Jonas Ringh ]

  *) mod_filter: fix FilterProvider matching where "dispatch" string
     doesn't exist.
     PR 48054 []

  *) Build: fix --with-module to work as documented
     PR 43881 [Gez Saunders ]

  *) mod_mime: Make RemoveType override the info from TypesConfig.
     PR 38330. [Stefan Fritsch]

  *) mod_proxy: unable to connect to a backend is SERVICE_UNAVAILABLE,
     rather than BAD_GATEWAY or (especially) NOT_FOUND.
     PR 46971 [evanc nortel.com]

  *) mod_charset_lite: Honor 'CharsetOptions NoImplicitAdd'.
     [Eric Covener]

  *) mod_ldap: If LDAPSharedCacheSize is too small, try harder to purge
     some cache entries and log a warning. Also increase the default
     LDAPSharedCacheSize to 500000. This is a more realistic size suitable
     for the default values of 1024 for LdapCacheEntries/LdapOpCacheEntries.
     PR 46749. [Stefan Fritsch]

  *) mod_disk_cache, mod_mem_cache: don't cache incomplete responses,
     per RFC 2616, 13.8.  PR15866.  [Dan Poirier]

  *) mod_rewrite: Make sure that a hostname:port isn't fully qualified if
     the request is a CONNECT request. PR 47928
     [Bill Zajac ]

  *) mod_cache: correctly consider s-maxage in cacheability
     decisions.  [Dan Poirier]

  *) core: Return APR_EOF if request body is shorter than the length announced
     by the client. PR 33098 [ Stefan Fritsch ]

  *) mod_rewrite: Add scgi scheme detection.  [André Malo]

  *) mod_mime: Detect invalid use of MultiviewsMatch inside Location and
     LocationMatch sections.  PR 47754.  [Dan Poirier]

  *) ab, mod_ssl: Restore compatibility with OpenSSL < 0.9.7g.
     [Guenter Knauf]