3 This Apache module provides strong cryptography for the Apache 2.0 webserver
4 via the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS
5 v1) protocols by the help of the SSL/TLS implementation library OpenSSL which
6 is based on SSLeay from Eric A. Young and Tim J. Hudson.
8 The mod_ssl package was created in April 1998 by Ralf S. Engelschall
9 and was originally derived from software developed by Ben Laurie for
10 use in the Apache-SSL HTTP server project. The mod_ssl implementation
11 for Apache 1.3 continues to be supported by the modssl project
12 <http://www.modssl.org/>.
16 See the top-level LAYOUT file in httpd-2.0 for file descriptions.
18 The source files are written in clean ANSI C and pass the ``gcc -O -g
19 -ggdb3 -Wall -Wshadow -Wpointer-arith -Wcast-align -Wmissing-prototypes
20 -Wmissing-declarations -Wnested-externs -Winline'' compiler test
21 (assuming `gcc' is GCC 2.95.2 or newer) without any complains. When
22 you make changes or additions make sure the source still passes this
27 Inside the source code you will be confronted with the following types of
28 functions which can be identified by their prefixes:
30 ap_xxxx() ............... Apache API function
31 ssl_xxxx() .............. mod_ssl function
32 SSL_xxxx() .............. OpenSSL function (SSL library)
33 OpenSSL_xxxx() .......... OpenSSL function (SSL library)
34 X509_xxxx() ............. OpenSSL function (Crypto library)
35 PEM_xxxx() .............. OpenSSL function (Crypto library)
36 EVP_xxxx() .............. OpenSSL function (Crypto library)
37 RSA_xxxx() .............. OpenSSL function (Crypto library)
41 Inside the source code you will be confronted with the following
44 server_rec .............. Apache (Virtual) Server
45 conn_rec ................ Apache Connection
46 request_rec ............. Apache Request
47 SSLModConfig ............ mod_ssl (Global) Module Configuration
48 SSLSrvConfig ............ mod_ssl (Virtual) Server Configuration
49 SSLDirConfig ............ mod_ssl Directory Configuration
50 SSLConnConfig ........... mod_ssl Connection Configuration
51 SSLFilterRec ............ mod_ssl Filter Context
52 SSL_CTX ................. OpenSSL Context
53 SSL_METHOD .............. OpenSSL Protocol Method
54 SSL_CIPHER .............. OpenSSL Cipher
55 SSL_SESSION ............. OpenSSL Session
56 SSL ..................... OpenSSL Connection
57 BIO ..................... OpenSSL Connection Buffer
59 For an overview how these are related and chained together have a look at the
60 page in README.dsov.{fig,ps}. It contains overview diagrams for those data
61 structures. It's designed for DIN A4 paper size, but you can easily generate
62 a smaller version inside XFig by specifing a magnification on the Export
67 Experimental code is always encapsulated as following:
69 | #ifdef SSL_EXPERIMENTAL_xxxx
73 This way it is only compiled in when this define is enabled with
74 the APACI --enable-rule=SSL_EXPERIMENTAL option and as long as the
75 C pre-processor variable SSL_EXPERIMENTAL_xxxx_IGNORE is _NOT_
76 defined (via CFLAGS). Or in other words: SSL_EXPERIMENTAL enables all
77 SSL_EXPERIMENTAL_xxxx variables, except if SSL_EXPERIMENTAL_xxxx_IGNORE
78 is already defined. Currently the following features are experimental:
80 o SSL_EXPERIMENTAL_ENGINE
81 The ability to support the new forthcoming OpenSSL ENGINE stuff.
82 Until this development branch of OpenSSL is merged into the main
83 stream, you have to use openssl-engine-0.9.x.tar.gz for this.
84 mod_ssl automatically recognizes this OpenSSL variant and then can
85 activate external crypto devices through SSLCryptoDevice directive.
89 The following intentional incompatibilities exist between mod_ssl 2.x
90 from Apache 1.3 and this mod_ssl version for Apache 2.0:
92 o The complete EAPI-based SSL_VENDOR stuff was removed.
93 o The complete EAPI-based SSL_COMPAT stuff was removed.
94 o The <IfDefine> variable MOD_SSL is no longer provided automatically
98 For a complete history of changes for Apache 2.0 mod_ssl, see the
99 CHANGES file in the top-level httpd-2.0 directory. The following
100 is a condensed summary of the major changes were made between
101 mod_ssl 2.x from Apache 1.3 and this mod_ssl version for Apache 2.0:
103 o The DBM based session cache is now based on APR's DBM API only.
104 o The shared memory based session cache is now based on APR's APIs.
105 o SSL I/O is now implemented in terms of filters rather than BUFF
106 o Eliminated ap_global_ctx. Storing Persistant information in
107 process_rec->pool->user_data. The ssl_pphrase_Handle_CB() and
108 ssl_config_global_* () functions have an extra parameter now -
109 "server_rec *" - which is used to retrieve the SSLModConfigRec.
110 o Properly support restarts, allowing mod_ssl to be added to a server
111 that is already running and to change server certs/keys on restart
112 o Various performance enhancements
113 o proxy support is no longer an "extension", much of the mod_ssl core
114 was re-written (ssl_engine_{init,kernel,config}.c) to be generic so
115 it could be re-used in proxy mode.
116 - the optional function ssl_proxy_enable is provide for mod_proxy
117 to enable proxy support
118 - proxy support now requires 'SSLProxyEngine on' to be configured
119 - proxy now supports SSLProxyCARevocation{Path,File} in addition to
120 the original SSLProxy* directives
121 o per-directory SSLCACertificate{File,Path} is now thread-safe but
122 requires SSL_set_cert_store patch to OpenSSL
123 o RSA sslc is supported via ssl_toolkit_compat.h
124 o the ssl_engine_{ds,ext}.c source files are obsolete and no longer
129 See the top-level STATUS file in httpd-2.0 for current efforts and goals.