SYNOPSIS This Apache module provides strong cryptography for the Apache 2 webserver via the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols by the help of the SSL/TLS implementation library OpenSSL which is based on SSLeay from Eric A. Young and Tim J. Hudson. The mod_ssl package was created in April 1998 by Ralf S. Engelschall and was originally derived from software developed by Ben Laurie for use in the Apache-SSL HTTP server project. The mod_ssl implementation for Apache 1.3 continues to be supported by the modssl project <http://www.modssl.org/>. SOURCES See the top-level LAYOUT file for file descriptions. The source files are written in clean ANSI C and pass the ``gcc -O -g -ggdb3 -Wall -Wshadow -Wpointer-arith -Wcast-align -Wmissing-prototypes -Wmissing-declarations -Wnested-externs -Winline'' compiler test (assuming `gcc' is GCC 2.95.2 or newer) without any complains. When you make changes or additions make sure the source still passes this compiler test. FUNCTIONS Inside the source code you will be confronted with the following types of functions which can be identified by their prefixes: ap_xxxx() ............... Apache API function ssl_xxxx() .............. mod_ssl function SSL_xxxx() .............. OpenSSL function (SSL library) OpenSSL_xxxx() .......... OpenSSL function (SSL library) X509_xxxx() ............. OpenSSL function (Crypto library) PEM_xxxx() .............. OpenSSL function (Crypto library) EVP_xxxx() .............. OpenSSL function (Crypto library) RSA_xxxx() .............. OpenSSL function (Crypto library) DATA STRUCTURES Inside the source code you will be confronted with the following data structures: server_rec .............. Apache (Virtual) Server conn_rec ................ Apache Connection request_rec ............. Apache Request SSLModConfig ............ mod_ssl (Global) Module Configuration SSLSrvConfig ............ mod_ssl (Virtual) Server Configuration SSLDirConfig ............ mod_ssl Directory Configuration SSLConnConfig ........... mod_ssl Connection Configuration SSLFilterRec ............ mod_ssl Filter Context SSL_CTX ................. OpenSSL Context SSL_METHOD .............. OpenSSL Protocol Method SSL_CIPHER .............. OpenSSL Cipher SSL_SESSION ............. OpenSSL Session SSL ..................... OpenSSL Connection BIO ..................... OpenSSL Connection Buffer For an overview how these are related and chained together have a look at the page in README.dsov.{fig,ps}. It contains overview diagrams for those data structures. It's designed for DIN A4 paper size, but you can easily generate a smaller version inside XFig by specifying a magnification on the Export panel. INCOMPATIBILITIES The following intentional incompatibilities exist between mod_ssl 2.x from Apache 1.3 and this mod_ssl version for Apache 2: o The complete EAPI-based SSL_VENDOR stuff was removed. o The complete EAPI-based SSL_COMPAT stuff was removed. o The <IfDefine> variable MOD_SSL is no longer provided automatically MAJOR CHANGES For a complete history of changes for Apache 2 mod_ssl, see the CHANGES file in the top-level directory. The following is a condensed summary of the major changes were made between mod_ssl 2.x from Apache 1.3 and this mod_ssl version for Apache 2: o The DBM based session cache is now based on APR's DBM API only. o The shared memory based session cache is now based on APR's APIs. o SSL I/O is now implemented in terms of filters rather than BUFF o Eliminated ap_global_ctx. Storing Persistent information in process_rec->pool->user_data. The ssl_pphrase_Handle_CB() and ssl_config_global_* () functions have an extra parameter now - "server_rec *" - which is used to retrieve the SSLModConfigRec. o Properly support restarts, allowing mod_ssl to be added to a server that is already running and to change server certs/keys on restart o Various performance enhancements o proxy support is no longer an "extension", much of the mod_ssl core was re-written (ssl_engine_{init,kernel,config}.c) to be generic so it could be re-used in proxy mode. - the optional function ssl_proxy_enable is provide for mod_proxy to enable proxy support - proxy support now requires 'SSLProxyEngine on' to be configured - proxy now supports SSLProxyCARevocation{Path,File} in addition to the original SSLProxy* directives o per-directory SSLCACertificate{File,Path} is now thread-safe but requires SSL_set_cert_store patch to OpenSSL o the ssl_engine_{ds,ext}.c source files are obsolete and no longer exist TODO See the top-level STATUS file for current efforts and goals.