Program: CWE-416
Project: CVE-2017-9798
Buggy source:
                                                         -*- coding: utf-8 -*-
Changes with Apache 2.5.0

  *) mod_md: v0.9.1:
     - various fixes in MDRenewWindow handling when specifying percent. Serialization changed. If 
       someone already used percent configurations, it is advised to change these to a new value,
       reload and change back to the wanted ones.
     - various fixes in handling of MDPrivateKeys when specifying 2048 bits (the default) explicitly.
     - mod_md version removed from top level md_store.json file. The store has its own format version
       to facilitate upgrades.
    [Stefan Eissing]

  *) mod_http2: DoS flow control protection is less agressive as long as active tasks stay
     below worker capacity. Intended to fix problems with media streaming. [Stefan Eissing]
     
  *) mod_md: v0.9.0:
     Certificate provisioning from Let's Encrypt (and other ACME CAs) for mod_ssl virtual hosts.
     [Stefan Eissing]
  
  *) mod_proxy: loadfactor parameter can now be a decimal number (eg: 1.25).
     [Jim Jagielski]

  *) mod_watchdog/mod_proxy_hcheck: Time intervals can now be spefified
     down to the millisecond. Supports 'mi' (minute), 'ms' (millisecond),
     's' (second) and 'hr' (hour!) time suffixes. [Jim Jagielski]

  *) mod_ssl: add SSLPolicy (define/use) and SSLProxyPolicy directives plus documentation. Add
     core definitions for policies 'modern', 'intermediate' and 'old', as defined by Mozilla
     in <https://wiki.mozilla.org/Security/Server_Side_TLS>. [Stefan Eissing]
     
  *) mod_proxy: Fix ProxyAddHeaders merging.  [Joe Orton]

  *) mod_md: new module for managing domains across VirtualHosts with ACME protocol 
     implementation for automated certificate signup and renewal. Default CA is
     the test area of Let's Encrypt right now, so certificates root will not be valid.
     Will be switched to the real service endpoint rather soon. If you need it now,
     configure 'MDCertificateAuthority https://acme-v01.api.letsencrypt.org/directory'.
     [Stefan Eissing] 
     
  *) mod_ssl, ab: Fix compatibility with LibreSSL.  PR 61184.
     [Bernard Spil <brnrd freebsd.org>, Yann Ylavic]

  *) event: Avoid possible blocking in the listener thread when shutting down
     connections. PR 60956.  [Yann Ylavic]

  *) mod_proxy_fcgi: Add the support for mod_proxy's flushpackets and flushwait
     parameters. [Luca Toscano, Ruediger Pluem, Yann Ylavic]

  *) mod_proxy_wstunnel: Fix detection of unresponded request which could have
     led to spurious HTTP 502 error messages sent on upgrade connections.
     PR 61283.  [Yann Ylavic]

  *) mod_http2: Simplify ready queue, less memory and better performance. Update
     mod_http2 version to 1.10.7. [Stefan Eissing]
  
  *) htpasswd / htdigest: Do not apply the strict permissions of the temporary
     passwd file to a possibly existing passwd file. PR 61240. [Ruediger Pluem]

  *) mod_rewrite: Add 'RewriteOptions LongURLOptimization' to free memory
     from each set of unmatched rewrite conditions.
     [Eric Covener]

  *) Allow the argument to <IfFile>, <IfDefine>, <IfSection>, <IfDirective>, 
     and <IfModule> to be quoted.  This is primarily for the benefit of
     <IfFile>. [Eric Covener]

  *) Introduce request taint checking framework to prevent privilege
     hijacking through .htaccess. [Nick Kew]

  *) core: Disallow multiple Listen on the same IP:port when listener buckets
     are configured (ListenCoresBucketsRatio > 0), consistently with the single
     bucket case (default), thus avoiding the leak of the corresponding socket
     descriptors on graceful restart.  [Yann Ylavic]

  *) Add <IfDirective> and <IfSection> directives.  [Joe Orton]

  *) mod_syslog: Support use of optional "tag" in syslog entries.
     PR 60525. [Ben Rubson <ben.rubson gmail.com>, Jim Jagielski]

  *) When using mod_status with the Event MPM, report the number of requests
     associated with an active connection in the "ACC" field. Previously
     zero was always reported with this MPM.  PR60647. [Eric Covener]

  *) mod_remoteip: Add support for PROXY protocol (code donated by Cloudzilla).
     Add ability for PROXY protocol processing to be optional to donated code.
     See also: http://www.haproxy.org/download/1.5/doc/proxy-protocol.txt
     [Cloudzilla/roadrunner2@GitHub, Jim Jagielski, Daniel Ruggeri]

  *) mod_remoteip: When overriding the useragent address from X-Forwarded-For,
     zero out what had been initialized as the connection-level port.  PR59931.
     [Hank Ibell <hwibell gmail.com>]

  *) mod_proxy_wstunnel: Reliably run before mod_proxy_http.
     [Eric Covener]

  *) mod_proxy_protocol: Add server-side, front-end support for PROXY PROTOCOL
     (http://blog.haproxy.com/haproxy/proxy-protocol/).  [roadrunner2]
     
  *) http: Allow unknown response status' lines returned in the form of
     "HTTP/x.x xxx Status xxx".  [Yann Ylavic]

  *) core: Add <IfFile> configuration section to allow any file on disk to be
     used as a conditional.  [Edward Lu, Eric Covener]

  *) event: Avoid listener periodic wake ups by using the pollset wake-ability
     when available.  PR 57399.  [Yann Ylavic, Luca Toscano]

  *) mod_crypto: Add the all purpose crypto filters with support for HLS.
     [Graham Leggett]

  *) core: Drop an invalid Last-Modified header value coming
     from a FCGI/CGI script instead of replacing it with Unix epoch.
     Warn the users about Last-Modified header value replacements
     and violations of the RFC.
     [Yann Ylavic, Luca Toscano, William Rowe, Jacob Champion]

  *) mod_dav: Allow other modules to become providers and add ACLs
     to the DAV response.
     [Jari Urpalainen <jari.urpalainen nokia.com>, Graham Leggett]

  *) mod_dav: Add dav_begin_multistatus, dav_send_one_response,
     dav_finish_multistatus, dav_send_multistatus, dav_handle_err,
     dav_failed_proppatch, dav_success_proppatch to mod_dav.h.
     [Jari Urpalainen <jari.urpalainen nokia.com>, Graham Leggett]

  *) mod_proxy, mod_ssl: Handle SSLProxy* directives in <Proxy> sections,
     allowing per backend TLS configuration.  [Yann Ylavic]

  *) core: explicitly exclude 'h2' from protocols announced via an Upgrade: 
     header as commanded by http-wg. [Stefan Eissing]

  *) mod_proxy_ajp: Add "secret" parameter to proxy workers to implement legacy
     AJP13 authentication.  PR 53098.  [Dmitry A. Bakshaev <dab1818 gmail com>]

  *) mpm: Generalise the ap_mpm_register_socket functions to accept pipes
     or sockets. [Graham Leggett]

  *) core: Extend support for setting aside data from the network input filter
     to any connection or request input filter. [Graham Leggett]

  *) core: Split ap_create_request() from ap_read_request(). [Graham Leggett]

  *) mod_auth_digest: Fix compatibility with expression-based Authname. PR59039.
     [Eric Covener]

  *) mpm: Add a complete_connection hook that confirms whether an MPM is allowed
     to leave the WRITE_COMPLETION phase. Move filter code out of the MPMs.
     [Graham Leggett]

  *) core: Added support for HTTP code 451. PR58985.
     [Yehuda Katz <yehuda ymkatz.net>, Jim Jagielski]

  *) mod_filter: Fix AddOutputFilterByType with non-content-level filters.
     PR58856 [Micha Lenk <micha lenk.info>]

  *) mod_cache: Consider Cache-Control: s-maxage in expiration
     calculations.  [Eric Covener]

  *) mod_cache: Allow caching of responses with an Expires header
     in the past that also has Cache-Control: max-age or s-maxage.
     PR55156. [Eric Covener]

  *) Added many log numbers to log statements that had none.

  *) mod_session: Introduce SessionExpiryUpdateInterval which allows to
     configure the session/cookie expiry's update interval. PR 57300.
     [Paul Spangler <paul.spangler ni.com>]

  *) core: Extend support for asynchronous write completion from the
     network filter to any connection or request filter. [Graham Leggett]

  *) mod_auth_digest: remove AuthDigestEnableQueryStringHack which is no
     more documented since dec 2012 (r1415960). [Christophe Jaillet]

  *) mod_charset_lite: On EBCDIC platforms, make sure mod_charset_lite runs
     after other resource-level filters. [Eric Covener]

  *) http: Don't remove the Content-Length of zero from a HEAD response if
     it comes from an origin server, module or script.  [Yann Ylavic]

  *) http: Add support for RFC2324/RFC7168. [Graham Leggett]

  *) mod_rewrite: Add support for starting External Rewriting Programs
     as non-root user on UNIX systems by specifying username and group name
     as third argument of RewriteMap directive. [Jan Kaluza]

  *) mod_authn_core: Add expression support to AuthName and AuthType.
     [Graham Leggett]

  *) suexec: Filter out the HTTP_PROXY environment variable because it is
     treated as alias for http_proxy by some programs. [Stefan Fritsch]

  *) mod_proxy_http: Don't establish or reuse a backend connection before pre-
     fetching the request body, so to minimize the delay between it is supposed
     to be alive and the first bytes sent: this is a best effort to prevent the
     backend from closing because of idle or keepalive timeout in the meantime.
     Also, handle a new "proxy-flushall" environment variable which allows to
     flush any forwarded body data immediately. PR 56541+37920. [Yann Ylavic]

  *) core: Define and UnDefine are no longer permitted in
     directory context. Previously they would always be evaulated
     as the configuration was read without regard for the directory
     context. [Eric Covener]

  *) config: For directives that do not expect any arguments, enforce
     that none are specified in the configuration file. 
     [Joachim Zobel <jzobel heute-morgen.de>, Eric Covener]

  *) mod_rewrite: Improve 'bad flag delimeters' startup error by showing
     how the input was tokenized.  PR 56528. [Edward Lu <Chaosed0 gmail.com>]

  *) mod_proxy: Don't put non balancer-member workers in error state by
     default for connection or 500/503 errors, and honor status=+I for
     any error.  PR 48388.  [Yann Ylavic]

  *) mod_socache_memcache: Pass expiration time through to memcached. PR 55445.
     [Faidon Liambotis <paravoid debian.org>, Joe Orton]

  *) ap_expr: Add filemod function for checking file modification dates
     [Daniel Gruno]

  *) mod_authnz_ldap: Resolve crashes with LDAP authz and non-LDAP authn since 
     r1608202. [Eric Covener]

  *) apreq: Content-Length header should be always interpreted as a decimal.
     Leading 0 could be erroneously considered as an octal value. PR 56598.
     [Chris Card <ctcard hotmail com>]

  *) mod_proxy: Now allow for 191 character worker names, with non-fatal
     errors if name is truncated. PR53218. [Jim Jagielski]

  *) mod_ssl: Add optional function "ssl_get_tls_cb" to allow support
     for channel bindings.  [Simo Sorce <simo redhat.com>]

  *) mod_proxy_wstunnel: Concurrent websockets messages could be 
     lost or delayed with ProxyWebsocketAsync enabled.  
     [Edward Lu <Chaosed0 gmail.com>]

  *) core, mod_info: Add compiled and loaded PCRE versions to version
     number display.  [Rainer Jung]

  *) mod_authnz_ldap: Return LDAP connections to the pool before the handler
     is run, instead of waiting until the end of the request. [Eric Covener]

  *) mod_proxy_html: support automatic detection of doctype and processing
     of FPIs.  PR56285 [Micha Lenk <micha lenk info>, Nick Kew]

  *) mod_proxy_html: skip documents shorter than 4 bytes
     PR 56286 [Micha Lenk <micha lenk info>]

  *) mod_proxy_fdpass: Fix computation of the size of 'struct sockaddr_un'
     when passed to 'connect()'.
     [Graham Dumpleton <grahamd apache org>]

  *) core: Add ap_mpm_resume_suspended() API to allow a suspended connection
     to resume. PR56333 
     [Artem <artemciy gmail.com>, Edward Lu <Chaosed0 gmail.com>]

  *) core: Add ap_mpm_register_socket_callback_timeout() API. [Eric Covener]

  *) mod_proxy_wstunnel: Honor ProxyWebsocketIdleTimeout in asynchronous
     processing mode. [Eric Covener]

  *) mod_authnz_ldap: Fail explicitly when the filter is too long. Remove
     unnecessary apr_pstrdup() and strlen(). [Graham Leggett]

  *) Add the ldap-search option to mod_authnz_ldap, allowing authorization
     to be based on arbitrary expressions that do not include the username.
     [Graham Leggett]

  *) Add the ldap function to the expression API, allowing LDAP filters and
     distinguished names based on expressions to be escaped correctly to
     guard against LDAP injection. [Graham Leggett]

  *) Add module mod_ssl_ct, which provides an implementation of Certificate
     Transparency (RFC 6962) for httpd.  [Jeff Trawick]

  *) mod_proxy_wstunnel: Avoid sending error responses down an upgraded
     websockets connection as it is being close down. [Eric Covener]

  *) mod_proxy_wstunnel: Allow the administrator to cap the amount
     of time a synchronous websockets connection stays idle with 
     ProxyWebsocketIdleTimeout. [Eric Covener]

  *) mod_proxy_wstunnel: Change to opt-in for asynchronous support, adding 
     directives ProxyWebsocketAsync and ProxyWebsocketAsyncDelay. 
     [Eric Covener]

  *) mod_proxy_wstunnel: Stop leaking websockets backend connections under
     event MPM (trunk-only). [Eric Covener]

  *) mod_proxy_http: Add detach_backend hook (potentially usable
     in other proxy scheme handlers).  [Jeff Trawick]

  *) mod_deflate: Add DeflateAlterETag to control how the ETag
     is modified. The 'NoChange' parameter mimics 2.2.x behavior.
     PR 45023, PR 39727. [Eric Covener]

  *) mod_rewrite: Add 'BNF' (backreferences-no-plus) flag to RewriteRule to 
     allow spaces in backreferences to be encoded as %20 instead of '+'.
     [Eric Covener]

  *) mod_rewrite: Support an optional list of characters to escape in the 
     argument for the 'B' (escape backreferences) flag. [Eric Covener]

  *) mod_dir: Default to 2.2-like behavior and skip execution when method is
     neither GET nor POST, such as for DAV requests. PR 54914. [Chris Darroch]

  *) mod_rewrite: Rename the handler that does per-directory internal 
     redirects to "rewrite-redirect-handler" from "redirect-handler" so
     it is less ambiguous and less likely to be reused. [Eric Covener]

  *) mod_rewrite: Protect against looping with the [N] flag by enforcing a 
     default limit of 10000 iterations, and allowing each rule to change its
     limit. [Eric Covener]

  *) mod_ssl: Fix config merging of SSLOCSPEnable and SSLOCSPOverrideResponder.
     [Jeff Trawick]

  *) Add HttpContentLengthHeadZero and HttpExpectStrict directives.
     [Yehuda Sadeh <yehuda inktank com>, Justin Erenkrantz]

  *) mod_ssl: Add -t -DDUMP_CA_CERTS option which dumps the filenames of all
     configured SSL CA certificates to stdout the same way as DUMP_CERTS does.
     [Jan Kaluza]

  *) mod_ssl: Don't flush when an EOS is received. Prepares mod_ssl
     to support write completion. [Graham Leggett]

  *) core: Add parse_errorlog_arg callback to ap_errorlog_provider
     to allow providers to check the ErrorLog argument. [Jan Kaluza]

  *) mod_cgid: Use the servers Timeout for each read from a CGI script,
     allow override with new CGIDRequestTimeout directive. PR43494
     [Eric Covener, Toshikuni Fukaya <toshikuni-fukaya cybozu co jp>]

  *) core: ensure any abnormal exit is reported to stderr if it's a tty.
     PR 55670 [Nick Kew]

  *) mod_lua: Let the Inter-VM get/set functions work with a global 
     shared memory pool instead of a per-process pool. [Daniel Gruno]

  *) ldap: Support ldaps when using the Microsoft LDAP SDK.
     PR 54626. [Jean-Frederic Clere]

  *) mod_authnz_ldap: Change default value of AuthLDAPMaxSubGroupDepth to 0
     to avoid performance problems when subgroups aren't in use. [Eric Covener]

  *) mod_syslog: New module implementing syslog ap_error_log provider.
     Previously, this code was part of core, now it's in separate module.
     [Jan Kaluza]

  *) core: Add ap_errorlog_provider to make ErrorLog logging modular. Move
     syslog support from core to new mod_syslog. [Jan Kaluza]

  *) mod_status, mod_echo: Fix the display of client addresses.
     They were truncated to 31 characters which is not enough for IPv6 addresses.
     PR 54848 [Bernhard Schmidt <berni birkenwald de>]

  *) mod_unique_id: Use output of the PRNG rather than IP address and
     pid, avoiding sleep() call and possible DNS issues at startup,
     plus improving randomness for IPv6-only hosts.
     [Jan Kaluza <jkaluza redhat.com>]

  *) mod_file_cache: mod_file_cache should be able to serve files that
     haven't had a Content-Type set via e.g. mod_mime. [Eric Covener]

  *) core: merge AllowEncodedSlashes from the base configuration into
     virtual hosts. [Eric Covener]

  *) AIX: Install DSO's with "cp" instead of "install" in instdso.sh
     [Eric Covener]

  *) mod_ldap: Don't keep retrying if a new LDAP connection times out.
     [Eric Covener]

  *) mod_deflate: permit compilation of mod_deflate against a zlib that has
     been configured with -D Z_PREFIX, which redefines the token "deflate".
     [Eric Covener]

  *) mod_auth_digest: Use the secret when generating nonces in all cases and
     not only when AuthName is used in .htaccess files (this change may cause
     problems if used with round robin load balancers). Don't regenerate the
     secret on graceful restarts. PR 54637  [Stefan Fritsch]

  *) core: Remove apr_brigade_flatten(), buffering and duplicated code
     from the HTTP_IN filter, parse chunks in a single pass with zero copy.
     Reduce memory usage by 48 bytes per request. [Graham Leggett]

  *) core: Stop the HTTP_IN filter from attempting to write error buckets
     to the output filters, which is bogus in the proxy case. Create a
     clean mapping from APR codes to HTTP status codes, and use it where
     needed. [Graham Leggett]

  *) mod_proxy: Ensure network errors detected by the proxy are returned as
     504 Gateway Timout as opposed to 502 Bad Gateway, in order to be
     compliant with RFC2616 14.9.4 Cache Revalidation and Reload Controls.

  *) mod_dav: mod_dav overrides dav_fs response on PUT failure. PR 35981
     [Basant Kumar Kukreja <basant.kukreja sun.com>, Alejandro Alvarez
     <alejandro.alvarez.ayllon cern.ch>]

  *) mod_ldap: LDAP connections used for authentication were not respecting
     LDAPConnectionPoolTimeout.  PR 54587

  *) core: ap_rgetline_core now pulls from r->proto_input_filters.

  *) mod_proxy_html: process parsed comments immediately. 
     Fixes bug where parsed comments may be lost. [Nick Kew]

  *) mod_proxy_html: introduce doctype for HTML 5 [Nick Kew]

  *) mod_proxy_html: fix typo-bug processing "strict" vs "transitional"
     HTML/XHTML [Nick Kew]

  *) core: Add option to add valgrind support. Use it to reduce false positive
     warnings in mod_ssl. [Stefan Fritsch]

  *) mod_authn_file, mod_authn_dbd, mod_authn_dbm, mod_authn_socache:
     Cache the result of the most recent password hash verification for every
     keep-alive connection. This saves some expensive calculations.
     [Stefan Fritsch]

  *) http: Remove support for Request-Range header sent by Navigator 2-3 and
     MSIE 3. [Stefan Fritsch]

  *) core, http: Extend HttpProtocol with an option to enforce stricter HTTP
     conformance or to only log the found problems. [Stefan Fritsch]

  *) core: Correctly parse an IPv6 literal host specification in an absolute
     URL in the request line. [Stefan Fritsch]

  *) EventOpt MPM

  *) core: Add LogLevelOverride directive that allows to override the
     loglevel for clients from certain IPs. This also works for things
     like the SSL handshake where <If> LogLevel ... </If> is evaluated
     too late. [Stefan Fritsch]

  *) core: Add new directive Warning to issue warnings from a configuration
     file. Both Warning and Error now generate a timestamped log message.
     [Fabien Coelho] 

  *) ap_expr: Add SERVER_PROTOCOL_VERSION, ..._MAJOR, and ..._MINOR
     variables. [Stefan Fritsch]

  *) core: New directive RegisterHttpMethod for registering non-standard
     HTTP methods. [Stefan Fritsch]

  *) core: New directive HttpProtocol which allows to disable HTTP/0.9
     support. [Stefan Fritsch]

  *) mod_allowhandlers: New module to forbid specific handlers for specific
     directories. [Stefan Fritsch]

  *) mod_systemd: New module, for integration with systemd on Linux.
     [Jan Kaluza <jkaluza redhat.com>]

  *) WinNT MPM: Store pid and generation for each thread in scoreboard
     to allow tracking of threads from exiting children via mod_status
     or other such mechanisms.  [Jeff Trawick]

  *) The following now respect DefaultRuntimeDir/DEFAULT_REL_RUNTIMEDIR:
     - APIs: ap_log_pid(), ap_remove_pid, ap_read_pid()
     - mod_cache: thundering herd lock directory
     - mod_lbmethod_heartbeat, mod_heartmonitor: heartbeat storage file
     - mod_ldap: shared memory cache
     - mod_socache_shmcb, mod_socache_dbm: shared memory or dbm for cache
     [Jeff Trawick]

  *) suexec: Add --enable-suexec-capabilites support on Linux, to use
     setuid/setgid capability bits rather than a setuid root binary.
     [Joe Orton]

  *) suexec: Add support for logging to syslog as an alternative to logging
     to a file; configure --without-suexec-logfile --with-suexec-syslog.  
     [Joe Orton]

  *) mod_ssl: Add support for TLS Next Protocol Negotiation.  PR 52210.
     [Matthew Steele <mdsteele google.com>]

  *) cross-compile: allow to provide CC_FOR_BUILD so that gen_test_char will
     be compiled by the build compiler instead of the host compiler.
     Also set CC_FOR_BUILD to 'cc' when cross-compilation is detected.
     PR 51257. [Guenter Knauf]

  *) core: In maintainer mode, replace apr_palloc with a version that
     initializes the allocated memory with non-zero values, except if
     AP_DEBUG_NO_ALLOC_POISON is defined. [Stefan Fritsch]

  *) mod_policy: Add a new testing module to help server administrators
     enforce a configurable level of protocol compliance on their
     servers and application servers behind theirs. [Graham Leggett]

  *) mod_firehose: Add a new debugging module able to record traffic
     passing through the server in such a way that connections and/or
     requests be reconstructed and replayed. [Graham Leggett]

  *) mod_noloris

  *) APREQ

  *) Simple MPM

  *) mod_serf

  [Apache 2.5.0-dev includes those bug fixes and changes with the
   Apache 2.4.xx tree as documented below, except as noted.]

Changes with Apache 2.4.x and later:

  *) http://svn.apache.org/viewvc/httpd/httpd/branches/2.4.x/CHANGES?view=markup

Changes with Apache 2.2.x and later:

  *) http://svn.apache.org/viewvc/httpd/httpd/branches/2.2.x/CHANGES?view=markup

Changes with Apache 2.0.x and later:

  *) http://svn.apache.org/viewvc/httpd/httpd/branches/2.0.x/CHANGES?view=markup



Fixed version (ground truth):
                                                         -*- coding: utf-8 -*-
Changes with Apache 2.5.0

  *) core: Disallow Methods' registration at runtime (.htaccess), they may be
     used only if registered at init time (httpd.conf).  [Yann Ylavic]

  *) mod_md: v0.9.1:
     - various fixes in MDRenewWindow handling when specifying percent. Serialization changed. If 
       someone already used percent configurations, it is advised to change these to a new value,
       reload and change back to the wanted ones.
     - various fixes in handling of MDPrivateKeys when specifying 2048 bits (the default) explicitly.
     - mod_md version removed from top level md_store.json file. The store has its own format version
       to facilitate upgrades.
    [Stefan Eissing]

  *) mod_http2: DoS flow control protection is less agressive as long as active tasks stay
     below worker capacity. Intended to fix problems with media streaming. [Stefan Eissing]
     
  *) mod_md: v0.9.0:
     Certificate provisioning from Let's Encrypt (and other ACME CAs) for mod_ssl virtual hosts.
     [Stefan Eissing]
  
  *) mod_proxy: loadfactor parameter can now be a decimal number (eg: 1.25).
     [Jim Jagielski]

  *) mod_watchdog/mod_proxy_hcheck: Time intervals can now be spefified
     down to the millisecond. Supports 'mi' (minute), 'ms' (millisecond),
     's' (second) and 'hr' (hour!) time suffixes. [Jim Jagielski]

  *) mod_ssl: add SSLPolicy (define/use) and SSLProxyPolicy directives plus documentation. Add
     core definitions for policies 'modern', 'intermediate' and 'old', as defined by Mozilla
     in <https://wiki.mozilla.org/Security/Server_Side_TLS>. [Stefan Eissing]
     
  *) mod_proxy: Fix ProxyAddHeaders merging.  [Joe Orton]

  *) mod_md: new module for managing domains across VirtualHosts with ACME protocol 
     implementation for automated certificate signup and renewal. Default CA is
     the test area of Let's Encrypt right now, so certificates root will not be valid.
     Will be switched to the real service endpoint rather soon. If you need it now,
     configure 'MDCertificateAuthority https://acme-v01.api.letsencrypt.org/directory'.
     [Stefan Eissing] 
     
  *) mod_ssl, ab: Fix compatibility with LibreSSL.  PR 61184.
     [Bernard Spil <brnrd freebsd.org>, Yann Ylavic]

  *) event: Avoid possible blocking in the listener thread when shutting down
     connections. PR 60956.  [Yann Ylavic]

  *) mod_proxy_fcgi: Add the support for mod_proxy's flushpackets and flushwait
     parameters. [Luca Toscano, Ruediger Pluem, Yann Ylavic]

  *) mod_proxy_wstunnel: Fix detection of unresponded request which could have
     led to spurious HTTP 502 error messages sent on upgrade connections.
     PR 61283.  [Yann Ylavic]

  *) mod_http2: Simplify ready queue, less memory and better performance. Update
     mod_http2 version to 1.10.7. [Stefan Eissing]
  
  *) htpasswd / htdigest: Do not apply the strict permissions of the temporary
     passwd file to a possibly existing passwd file. PR 61240. [Ruediger Pluem]

  *) mod_rewrite: Add 'RewriteOptions LongURLOptimization' to free memory
     from each set of unmatched rewrite conditions.
     [Eric Covener]

  *) Allow the argument to <IfFile>, <IfDefine>, <IfSection>, <IfDirective>, 
     and <IfModule> to be quoted.  This is primarily for the benefit of
     <IfFile>. [Eric Covener]

  *) Introduce request taint checking framework to prevent privilege
     hijacking through .htaccess. [Nick Kew]

  *) core: Disallow multiple Listen on the same IP:port when listener buckets
     are configured (ListenCoresBucketsRatio > 0), consistently with the single
     bucket case (default), thus avoiding the leak of the corresponding socket
     descriptors on graceful restart.  [Yann Ylavic]

  *) Add <IfDirective> and <IfSection> directives.  [Joe Orton]

  *) mod_syslog: Support use of optional "tag" in syslog entries.
     PR 60525. [Ben Rubson <ben.rubson gmail.com>, Jim Jagielski]

  *) When using mod_status with the Event MPM, report the number of requests
     associated with an active connection in the "ACC" field. Previously
     zero was always reported with this MPM.  PR60647. [Eric Covener]

  *) mod_remoteip: Add support for PROXY protocol (code donated by Cloudzilla).
     Add ability for PROXY protocol processing to be optional to donated code.
     See also: http://www.haproxy.org/download/1.5/doc/proxy-protocol.txt
     [Cloudzilla/roadrunner2@GitHub, Jim Jagielski, Daniel Ruggeri]

  *) mod_remoteip: When overriding the useragent address from X-Forwarded-For,
     zero out what had been initialized as the connection-level port.  PR59931.
     [Hank Ibell <hwibell gmail.com>]

  *) mod_proxy_wstunnel: Reliably run before mod_proxy_http.
     [Eric Covener]

  *) mod_proxy_protocol: Add server-side, front-end support for PROXY PROTOCOL
     (http://blog.haproxy.com/haproxy/proxy-protocol/).  [roadrunner2]
     
  *) http: Allow unknown response status' lines returned in the form of
     "HTTP/x.x xxx Status xxx".  [Yann Ylavic]

  *) core: Add <IfFile> configuration section to allow any file on disk to be
     used as a conditional.  [Edward Lu, Eric Covener]

  *) event: Avoid listener periodic wake ups by using the pollset wake-ability
     when available.  PR 57399.  [Yann Ylavic, Luca Toscano]

  *) mod_crypto: Add the all purpose crypto filters with support for HLS.
     [Graham Leggett]

  *) core: Drop an invalid Last-Modified header value coming
     from a FCGI/CGI script instead of replacing it with Unix epoch.
     Warn the users about Last-Modified header value replacements
     and violations of the RFC.
     [Yann Ylavic, Luca Toscano, William Rowe, Jacob Champion]

  *) mod_dav: Allow other modules to become providers and add ACLs
     to the DAV response.
     [Jari Urpalainen <jari.urpalainen nokia.com>, Graham Leggett]

  *) mod_dav: Add dav_begin_multistatus, dav_send_one_response,
     dav_finish_multistatus, dav_send_multistatus, dav_handle_err,
     dav_failed_proppatch, dav_success_proppatch to mod_dav.h.
     [Jari Urpalainen <jari.urpalainen nokia.com>, Graham Leggett]

  *) mod_proxy, mod_ssl: Handle SSLProxy* directives in <Proxy> sections,
     allowing per backend TLS configuration.  [Yann Ylavic]

  *) core: explicitly exclude 'h2' from protocols announced via an Upgrade: 
     header as commanded by http-wg. [Stefan Eissing]

  *) mod_proxy_ajp: Add "secret" parameter to proxy workers to implement legacy
     AJP13 authentication.  PR 53098.  [Dmitry A. Bakshaev <dab1818 gmail com>]

  *) mpm: Generalise the ap_mpm_register_socket functions to accept pipes
     or sockets. [Graham Leggett]

  *) core: Extend support for setting aside data from the network input filter
     to any connection or request input filter. [Graham Leggett]

  *) core: Split ap_create_request() from ap_read_request(). [Graham Leggett]

  *) mod_auth_digest: Fix compatibility with expression-based Authname. PR59039.
     [Eric Covener]

  *) mpm: Add a complete_connection hook that confirms whether an MPM is allowed
     to leave the WRITE_COMPLETION phase. Move filter code out of the MPMs.
     [Graham Leggett]

  *) core: Added support for HTTP code 451. PR58985.
     [Yehuda Katz <yehuda ymkatz.net>, Jim Jagielski]

  *) mod_filter: Fix AddOutputFilterByType with non-content-level filters.
     PR58856 [Micha Lenk <micha lenk.info>]

  *) mod_cache: Consider Cache-Control: s-maxage in expiration
     calculations.  [Eric Covener]

  *) mod_cache: Allow caching of responses with an Expires header
     in the past that also has Cache-Control: max-age or s-maxage.
     PR55156. [Eric Covener]

  *) Added many log numbers to log statements that had none.

  *) mod_session: Introduce SessionExpiryUpdateInterval which allows to
     configure the session/cookie expiry's update interval. PR 57300.
     [Paul Spangler <paul.spangler ni.com>]

  *) core: Extend support for asynchronous write completion from the
     network filter to any connection or request filter. [Graham Leggett]

  *) mod_auth_digest: remove AuthDigestEnableQueryStringHack which is no
     more documented since dec 2012 (r1415960). [Christophe Jaillet]

  *) mod_charset_lite: On EBCDIC platforms, make sure mod_charset_lite runs
     after other resource-level filters. [Eric Covener]

  *) http: Don't remove the Content-Length of zero from a HEAD response if
     it comes from an origin server, module or script.  [Yann Ylavic]

  *) http: Add support for RFC2324/RFC7168. [Graham Leggett]

  *) mod_rewrite: Add support for starting External Rewriting Programs
     as non-root user on UNIX systems by specifying username and group name
     as third argument of RewriteMap directive. [Jan Kaluza]

  *) mod_authn_core: Add expression support to AuthName and AuthType.
     [Graham Leggett]

  *) suexec: Filter out the HTTP_PROXY environment variable because it is
     treated as alias for http_proxy by some programs. [Stefan Fritsch]

  *) mod_proxy_http: Don't establish or reuse a backend connection before pre-
     fetching the request body, so to minimize the delay between it is supposed
     to be alive and the first bytes sent: this is a best effort to prevent the
     backend from closing because of idle or keepalive timeout in the meantime.
     Also, handle a new "proxy-flushall" environment variable which allows to
     flush any forwarded body data immediately. PR 56541+37920. [Yann Ylavic]

  *) core: Define and UnDefine are no longer permitted in
     directory context. Previously they would always be evaulated
     as the configuration was read without regard for the directory
     context. [Eric Covener]

  *) config: For directives that do not expect any arguments, enforce
     that none are specified in the configuration file. 
     [Joachim Zobel <jzobel heute-morgen.de>, Eric Covener]

  *) mod_rewrite: Improve 'bad flag delimeters' startup error by showing
     how the input was tokenized.  PR 56528. [Edward Lu <Chaosed0 gmail.com>]

  *) mod_proxy: Don't put non balancer-member workers in error state by
     default for connection or 500/503 errors, and honor status=+I for
     any error.  PR 48388.  [Yann Ylavic]

  *) mod_socache_memcache: Pass expiration time through to memcached. PR 55445.
     [Faidon Liambotis <paravoid debian.org>, Joe Orton]

  *) ap_expr: Add filemod function for checking file modification dates
     [Daniel Gruno]

  *) mod_authnz_ldap: Resolve crashes with LDAP authz and non-LDAP authn since 
     r1608202. [Eric Covener]

  *) apreq: Content-Length header should be always interpreted as a decimal.
     Leading 0 could be erroneously considered as an octal value. PR 56598.
     [Chris Card <ctcard hotmail com>]

  *) mod_proxy: Now allow for 191 character worker names, with non-fatal
     errors if name is truncated. PR53218. [Jim Jagielski]

  *) mod_ssl: Add optional function "ssl_get_tls_cb" to allow support
     for channel bindings.  [Simo Sorce <simo redhat.com>]

  *) mod_proxy_wstunnel: Concurrent websockets messages could be 
     lost or delayed with ProxyWebsocketAsync enabled.  
     [Edward Lu <Chaosed0 gmail.com>]

  *) core, mod_info: Add compiled and loaded PCRE versions to version
     number display.  [Rainer Jung]

  *) mod_authnz_ldap: Return LDAP connections to the pool before the handler
     is run, instead of waiting until the end of the request. [Eric Covener]

  *) mod_proxy_html: support automatic detection of doctype and processing
     of FPIs.  PR56285 [Micha Lenk <micha lenk info>, Nick Kew]

  *) mod_proxy_html: skip documents shorter than 4 bytes
     PR 56286 [Micha Lenk <micha lenk info>]

  *) mod_proxy_fdpass: Fix computation of the size of 'struct sockaddr_un'
     when passed to 'connect()'.
     [Graham Dumpleton <grahamd apache org>]

  *) core: Add ap_mpm_resume_suspended() API to allow a suspended connection
     to resume. PR56333 
     [Artem <artemciy gmail.com>, Edward Lu <Chaosed0 gmail.com>]

  *) core: Add ap_mpm_register_socket_callback_timeout() API. [Eric Covener]

  *) mod_proxy_wstunnel: Honor ProxyWebsocketIdleTimeout in asynchronous
     processing mode. [Eric Covener]

  *) mod_authnz_ldap: Fail explicitly when the filter is too long. Remove
     unnecessary apr_pstrdup() and strlen(). [Graham Leggett]

  *) Add the ldap-search option to mod_authnz_ldap, allowing authorization
     to be based on arbitrary expressions that do not include the username.
     [Graham Leggett]

  *) Add the ldap function to the expression API, allowing LDAP filters and
     distinguished names based on expressions to be escaped correctly to
     guard against LDAP injection. [Graham Leggett]

  *) Add module mod_ssl_ct, which provides an implementation of Certificate
     Transparency (RFC 6962) for httpd.  [Jeff Trawick]

  *) mod_proxy_wstunnel: Avoid sending error responses down an upgraded
     websockets connection as it is being close down. [Eric Covener]

  *) mod_proxy_wstunnel: Allow the administrator to cap the amount
     of time a synchronous websockets connection stays idle with 
     ProxyWebsocketIdleTimeout. [Eric Covener]

  *) mod_proxy_wstunnel: Change to opt-in for asynchronous support, adding 
     directives ProxyWebsocketAsync and ProxyWebsocketAsyncDelay. 
     [Eric Covener]

  *) mod_proxy_wstunnel: Stop leaking websockets backend connections under
     event MPM (trunk-only). [Eric Covener]

  *) mod_proxy_http: Add detach_backend hook (potentially usable
     in other proxy scheme handlers).  [Jeff Trawick]

  *) mod_deflate: Add DeflateAlterETag to control how the ETag
     is modified. The 'NoChange' parameter mimics 2.2.x behavior.
     PR 45023, PR 39727. [Eric Covener]

  *) mod_rewrite: Add 'BNF' (backreferences-no-plus) flag to RewriteRule to 
     allow spaces in backreferences to be encoded as %20 instead of '+'.
     [Eric Covener]

  *) mod_rewrite: Support an optional list of characters to escape in the 
     argument for the 'B' (escape backreferences) flag. [Eric Covener]

  *) mod_dir: Default to 2.2-like behavior and skip execution when method is
     neither GET nor POST, such as for DAV requests. PR 54914. [Chris Darroch]

  *) mod_rewrite: Rename the handler that does per-directory internal 
     redirects to "rewrite-redirect-handler" from "redirect-handler" so
     it is less ambiguous and less likely to be reused. [Eric Covener]

  *) mod_rewrite: Protect against looping with the [N] flag by enforcing a 
     default limit of 10000 iterations, and allowing each rule to change its
     limit. [Eric Covener]

  *) mod_ssl: Fix config merging of SSLOCSPEnable and SSLOCSPOverrideResponder.
     [Jeff Trawick]

  *) Add HttpContentLengthHeadZero and HttpExpectStrict directives.
     [Yehuda Sadeh <yehuda inktank com>, Justin Erenkrantz]

  *) mod_ssl: Add -t -DDUMP_CA_CERTS option which dumps the filenames of all
     configured SSL CA certificates to stdout the same way as DUMP_CERTS does.
     [Jan Kaluza]

  *) mod_ssl: Don't flush when an EOS is received. Prepares mod_ssl
     to support write completion. [Graham Leggett]

  *) core: Add parse_errorlog_arg callback to ap_errorlog_provider
     to allow providers to check the ErrorLog argument. [Jan Kaluza]

  *) mod_cgid: Use the servers Timeout for each read from a CGI script,
     allow override with new CGIDRequestTimeout directive. PR43494
     [Eric Covener, Toshikuni Fukaya <toshikuni-fukaya cybozu co jp>]

  *) core: ensure any abnormal exit is reported to stderr if it's a tty.
     PR 55670 [Nick Kew]

  *) mod_lua: Let the Inter-VM get/set functions work with a global 
     shared memory pool instead of a per-process pool. [Daniel Gruno]

  *) ldap: Support ldaps when using the Microsoft LDAP SDK.
     PR 54626. [Jean-Frederic Clere]

  *) mod_authnz_ldap: Change default value of AuthLDAPMaxSubGroupDepth to 0
     to avoid performance problems when subgroups aren't in use. [Eric Covener]

  *) mod_syslog: New module implementing syslog ap_error_log provider.
     Previously, this code was part of core, now it's in separate module.
     [Jan Kaluza]

  *) core: Add ap_errorlog_provider to make ErrorLog logging modular. Move
     syslog support from core to new mod_syslog. [Jan Kaluza]

  *) mod_status, mod_echo: Fix the display of client addresses.
     They were truncated to 31 characters which is not enough for IPv6 addresses.
     PR 54848 [Bernhard Schmidt <berni birkenwald de>]

  *) mod_unique_id: Use output of the PRNG rather than IP address and
     pid, avoiding sleep() call and possible DNS issues at startup,
     plus improving randomness for IPv6-only hosts.
     [Jan Kaluza <jkaluza redhat.com>]

  *) mod_file_cache: mod_file_cache should be able to serve files that
     haven't had a Content-Type set via e.g. mod_mime. [Eric Covener]

  *) core: merge AllowEncodedSlashes from the base configuration into
     virtual hosts. [Eric Covener]

  *) AIX: Install DSO's with "cp" instead of "install" in instdso.sh
     [Eric Covener]

  *) mod_ldap: Don't keep retrying if a new LDAP connection times out.
     [Eric Covener]

  *) mod_deflate: permit compilation of mod_deflate against a zlib that has
     been configured with -D Z_PREFIX, which redefines the token "deflate".
     [Eric Covener]

  *) mod_auth_digest: Use the secret when generating nonces in all cases and
     not only when AuthName is used in .htaccess files (this change may cause
     problems if used with round robin load balancers). Don't regenerate the
     secret on graceful restarts. PR 54637  [Stefan Fritsch]

  *) core: Remove apr_brigade_flatten(), buffering and duplicated code
     from the HTTP_IN filter, parse chunks in a single pass with zero copy.
     Reduce memory usage by 48 bytes per request. [Graham Leggett]

  *) core: Stop the HTTP_IN filter from attempting to write error buckets
     to the output filters, which is bogus in the proxy case. Create a
     clean mapping from APR codes to HTTP status codes, and use it where
     needed. [Graham Leggett]

  *) mod_proxy: Ensure network errors detected by the proxy are returned as
     504 Gateway Timout as opposed to 502 Bad Gateway, in order to be
     compliant with RFC2616 14.9.4 Cache Revalidation and Reload Controls.

  *) mod_dav: mod_dav overrides dav_fs response on PUT failure. PR 35981
     [Basant Kumar Kukreja <basant.kukreja sun.com>, Alejandro Alvarez
     <alejandro.alvarez.ayllon cern.ch>]

  *) mod_ldap: LDAP connections used for authentication were not respecting
     LDAPConnectionPoolTimeout.  PR 54587

  *) core: ap_rgetline_core now pulls from r->proto_input_filters.

  *) mod_proxy_html: process parsed comments immediately. 
     Fixes bug where parsed comments may be lost. [Nick Kew]

  *) mod_proxy_html: introduce doctype for HTML 5 [Nick Kew]

  *) mod_proxy_html: fix typo-bug processing "strict" vs "transitional"
     HTML/XHTML [Nick Kew]

  *) core: Add option to add valgrind support. Use it to reduce false positive
     warnings in mod_ssl. [Stefan Fritsch]

  *) mod_authn_file, mod_authn_dbd, mod_authn_dbm, mod_authn_socache:
     Cache the result of the most recent password hash verification for every
     keep-alive connection. This saves some expensive calculations.
     [Stefan Fritsch]

  *) http: Remove support for Request-Range header sent by Navigator 2-3 and
     MSIE 3. [Stefan Fritsch]

  *) core, http: Extend HttpProtocol with an option to enforce stricter HTTP
     conformance or to only log the found problems. [Stefan Fritsch]

  *) core: Correctly parse an IPv6 literal host specification in an absolute
     URL in the request line. [Stefan Fritsch]

  *) EventOpt MPM

  *) core: Add LogLevelOverride directive that allows to override the
     loglevel for clients from certain IPs. This also works for things
     like the SSL handshake where <If> LogLevel ... </If> is evaluated
     too late. [Stefan Fritsch]

  *) core: Add new directive Warning to issue warnings from a configuration
     file. Both Warning and Error now generate a timestamped log message.
     [Fabien Coelho] 

  *) ap_expr: Add SERVER_PROTOCOL_VERSION, ..._MAJOR, and ..._MINOR
     variables. [Stefan Fritsch]

  *) core: New directive RegisterHttpMethod for registering non-standard
     HTTP methods. [Stefan Fritsch]

  *) core: New directive HttpProtocol which allows to disable HTTP/0.9
     support. [Stefan Fritsch]

  *) mod_allowhandlers: New module to forbid specific handlers for specific
     directories. [Stefan Fritsch]

  *) mod_systemd: New module, for integration with systemd on Linux.
     [Jan Kaluza <jkaluza redhat.com>]

  *) WinNT MPM: Store pid and generation for each thread in scoreboard
     to allow tracking of threads from exiting children via mod_status
     or other such mechanisms.  [Jeff Trawick]

  *) The following now respect DefaultRuntimeDir/DEFAULT_REL_RUNTIMEDIR:
     - APIs: ap_log_pid(), ap_remove_pid, ap_read_pid()
     - mod_cache: thundering herd lock directory
     - mod_lbmethod_heartbeat, mod_heartmonitor: heartbeat storage file
     - mod_ldap: shared memory cache
     - mod_socache_shmcb, mod_socache_dbm: shared memory or dbm for cache
     [Jeff Trawick]

  *) suexec: Add --enable-suexec-capabilites support on Linux, to use
     setuid/setgid capability bits rather than a setuid root binary.
     [Joe Orton]

  *) suexec: Add support for logging to syslog as an alternative to logging
     to a file; configure --without-suexec-logfile --with-suexec-syslog.  
     [Joe Orton]

  *) mod_ssl: Add support for TLS Next Protocol Negotiation.  PR 52210.
     [Matthew Steele <mdsteele google.com>]

  *) cross-compile: allow to provide CC_FOR_BUILD so that gen_test_char will
     be compiled by the build compiler instead of the host compiler.
     Also set CC_FOR_BUILD to 'cc' when cross-compilation is detected.
     PR 51257. [Guenter Knauf]

  *) core: In maintainer mode, replace apr_palloc with a version that
     initializes the allocated memory with non-zero values, except if
     AP_DEBUG_NO_ALLOC_POISON is defined. [Stefan Fritsch]

  *) mod_policy: Add a new testing module to help server administrators
     enforce a configurable level of protocol compliance on their
     servers and application servers behind theirs. [Graham Leggett]

  *) mod_firehose: Add a new debugging module able to record traffic
     passing through the server in such a way that connections and/or
     requests be reconstructed and replayed. [Graham Leggett]

  *) mod_noloris

  *) APREQ

  *) Simple MPM

  *) mod_serf

  [Apache 2.5.0-dev includes those bug fixes and changes with the
   Apache 2.4.xx tree as documented below, except as noted.]

Changes with Apache 2.4.x and later:

  *) http://svn.apache.org/viewvc/httpd/httpd/branches/2.4.x/CHANGES?view=markup

Changes with Apache 2.2.x and later:

  *) http://svn.apache.org/viewvc/httpd/httpd/branches/2.2.x/CHANGES?view=markup

Changes with Apache 2.0.x and later:

  *) http://svn.apache.org/viewvc/httpd/httpd/branches/2.0.x/CHANGES?view=markup