本文介绍如何为 Apache2 创建自签名SSL证书，虽然自签名证书不能受第三方浏览器信任（无法验证服务器身份），但能够起到安全传输信息的作用。可以考虑使用 Let’s Encrypt 颁发大多数Web浏览器都信任的免费SSL/TLS证书，请参考链接：How To Secure Apache with Let’s Encrypt on Ubuntu 14.04
一、Ubuntu环境
以Ubuntu 14.04为例，如果没有安装 Apache ，则可通过如下命令快速安装：
[who@ubuntu ~]# sudo apt-get update [who@ubuntu ~]# sudo apt-get install apache2
1. 启用SSL模块
SSL支持是 Ubuntu 14.04 Apache 软件包的标准配置，只需要启用即可：
[who@ubuntu ~]# sudo a2enmod ssl [who@ubuntu ~]# sudo apachectl restart
2. 创建自签名证书
创建一个目录用于放置密钥和证书文件：
[who@ubuntu ~]# sudo mkdir /etc/apache2/ssl
创建私钥和证书：
[who@ubuntu ~]# sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/apache2/ssl/server.key -out /etc/apache2/ssl/server.crt
其中，openssl是OpenSSL提供的基本命令行工具；req指定了X.509证书签名请求（CSR）管理的子命令；-x509选项指定了创建自签名证书而不是生成证书请求；-nodes选项告诉OpenSSL不使用密码来保护密钥文件，受密码保护的密钥文件会使得Apache服务重新启动时必须输入密码；-days选项指定了证书有效期为多少天；-newkey rsa:2048选项指定了同时创建私钥，私钥为2048位的RSA密钥；-keyout选项指定了私钥输出文件路径；-out指定了证书输出文件路径。
执行上述命令会被要求回答几个问题：
Country Name (2 letter code) [AU]:US State or Province Name (full name) [Some-State]:New York Locality Name (eg, city) []:New York City Organization Name (eg, company) [Internet Widgits Pty Ltd]:Your Company Organizational Unit Name (eg, section) []:Department of Kittens Common Name (e.g. server FQDN or YOUR name) []:your_domain Email Address []:your_email
其中，最重要的是Common Name，应输入要与证书关联的域名，如果没有域名，则输入服务器的公共IP地址。
3. 配置Apache使用SSL证书
文件/etc/apache2/sites-available/default-ssl.conf的默认内容如下：
<IfModule mod_ssl.c>
<VirtualHost _default_:443>
ServerAdmin webmaster@localhost
DocumentRoot /var/www/html
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
SSLEngine on
SSLCertificateFile /etc/ssl/certs/ssl-cert-snakeoil.pem
SSLCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key
<FilesMatch "\.(cgi|shtml|phtml|php)$">
SSLOptions +StdEnvVars
</FilesMatch>
<Directory /usr/lib/cgi-bin>
SSLOptions +StdEnvVars
</Directory>
BrowserMatch "MSIE [2-6]" \
nokeepalive ssl-unclean-shutdown \
downgrade-1.0 force-response-1.0
BrowserMatch "MSIE [17-9]" ssl-unclean-shutdown
</VirtualHost>
</IfModule>
将其修改为：
<IfModule mod_ssl.c>
<VirtualHost _default_:443>
ServerAdmin [email protected]
ServerName your_domain
ServerAlias www.your_domain
DocumentRoot /var/www/html
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
SSLEngine on
SSLCertificateFile /etc/apache2/ssl/server.crt
SSLCertificateKeyFile /etc/apache2/ssl/server.key
<FilesMatch "\.(cgi|shtml|phtml|php)$">
SSLOptions +StdEnvVars
</FilesMatch>
<Directory /usr/lib/cgi-bin>
SSLOptions +StdEnvVars
</Directory>
BrowserMatch "MSIE [2-6]" \
nokeepalive ssl-unclean-shutdown \
downgrade-1.0 force-response-1.0
BrowserMatch "MSIE [17-9]" ssl-unclean-shutdown
</VirtualHost>
</IfModule>
同时，文件/etc/apache2/ports.conf中应包含以下内容：
<IfModule ssl_module>
Listen 443
</IfModule>
<IfModule mod_gnutls.c>
Listen 443
</IfModule>
然后激活并重启Apache即可：
[who@ubuntu ~]# sudo a2ensite default-ssl.conf [who@ubuntu ~]# sudo apachectl restart
也可通过以下命令重启：
[who@ubuntu ~]# sudo /etc/init.d/apache2 force-reload [who@ubuntu ~]# sudo /etc/init.d/apache2 restart
二、Centos环境
如果没有安装 Apache ，则可通过如下命令快速安装：
[who@centos ~]# sudo yum -y install httpd
1. 安装SSL模块
参考：https://www.cnblogs.com/ryanlamp/p/6377637.html
Centos Apache 一般不支持SSL，需要安装：
[who@centos ~]# sudo yum -y install mod_ssl
2. 创建自签名证书
同上，将其中ssl证书存放路径改为/etc/httpd/ssl目录。
3. 配置Apache使用SSL证书
文件/etc/httpd/conf.d/ssl.conf的默认内容如下：
LoadModule ssl_module modules/mod_ssl.so
Listen 443
SSLPassPhraseDialog builtin
SSLSessionCache shmcb:/var/cache/mod_ssl/scache(512000)
SSLSessionCacheTimeout 300
SSLMutex default
SSLRandomSeed startup file:/dev/urandom 256
SSLRandomSeed connect builtin
SSLCryptoDevice builtin
<VirtualHost _default_:443>
#DocumentRoot "/var/www/html"
#ServerName www.example.com:443
ErrorLog logs/ssl_error_log
TransferLog logs/ssl_access_log
LogLevel warn
SSLEngine on
SSLProtocol all -SSLv2
SSLCipherSuite DEFAULT:!EXP:!SSLv2:!DES:!IDEA:!SEED:+3DES
SSLCertificateFile /etc/pki/tls/certs/localhost.crt
SSLCertificateKeyFile /etc/pki/tls/private/localhost.key
<Files ~ "\.(cgi|shtml|phtml|php3?)$">
SSLOptions +StdEnvVars
</Files>
<Directory "/var/www/cgi-bin">
SSLOptions +StdEnvVars
</Directory>
SetEnvIf User-Agent ".*MSIE.*" \
nokeepalive ssl-unclean-shutdown \
downgrade-1.0 force-response-1.0
CustomLog logs/ssl_request_log \
"%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"
</VirtualHost>
将其修改为：
LoadModule ssl_module modules/mod_ssl.so
Listen 443
SSLPassPhraseDialog builtin
SSLSessionCache shmcb:/var/cache/mod_ssl/scache(512000)
SSLSessionCacheTimeout 300
SSLMutex default
SSLRandomSeed startup file:/dev/urandom 256
SSLRandomSeed connect builtin
SSLCryptoDevice builtin
<VirtualHost _default_:443>
DocumentRoot "/var/www/html"
ServerName your_domain
ErrorLog logs/ssl_error_log
TransferLog logs/ssl_access_log
LogLevel warn
SSLEngine on
SSLProtocol all -SSLv2
SSLCipherSuite DEFAULT:!EXP:!SSLv2:!DES:!IDEA:!SEED:+3DES
SSLCertificateFile /etc/httpd/ssl/server.crt
SSLCertificateKeyFile /etc/httpd/ssl/server.key
<Files ~ "\.(cgi|shtml|phtml|php3?)$">
SSLOptions +StdEnvVars
</Files>
<Directory "/var/www/cgi-bin">
SSLOptions +StdEnvVars
</Directory>
SetEnvIf User-Agent ".*MSIE.*" \
nokeepalive ssl-unclean-shutdown \
downgrade-1.0 force-response-1.0
CustomLog logs/ssl_request_log \
"%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"
</VirtualHost>
确保/etc/httpd/conf/httpd.conf文件中包含Include conf.d/*.conf语句，然后重启httpd服务即可。