So you have a web-server and you want to serve content by SSL? If you have found you way to here, you have probably discovered that browsers such as Firefox do not make it easy to use self-signed certificates; large scary error messages do not inspire confidence in most users. But there is an easy answer – StartSSL.
Update: Much of the information in this post is now outdated, and StartSSL are no longer issuing certificates. Please see our post on using Letsencrypt instead.
For the purposes of this blog, I’ll be using a free class 1 certificate to secure apache running on Ubuntu Maverick.
Getting the key and certificate from StartSSL
Startcom, in the guise of StartSSL provide free SSL certificates to domains by means of electronic confirmations. Class 1 certificates are only valid for a year (you just produce a new certificate every year) and provide protection against eavesdropping. They do not provide any verification of the identity of the site owner; that is a service you rightly pay for as it is somewhat more involved and involves manual confirmation of certain details. They will only produce certificates for domains you own; this is checked automatically during the process.
StartSSL CA certificates come pre-installed in the majority of browsers including Firefox, IE, Chrome, Safari, Opera, Konqueror: you get the picture; your visitors are going to have eavesdropping protection pretty much whatever system they run.
Start by signing up here (currently not possible with Chrome). A certificate will be created during the signup identifying you by email address which will be installed in your browser. Once that is complete, use the Validation Wizard in the Toolbox to validate a domain (choose Domain Name Vaidation from the drop-down box); this is done by sending a verification code to a chosen email address associated with that domain.
Once the domain is verified, use the Certificates Wizard to produce a Web Server SSL/TLS Certificate. Enter a strong password and choose the keysize you wish. Once you continue, you will be presented with the private key; copy/paste this to a text editor such as gedit and save the file locally as my.server.key.
Continue again and choose the verified domain from the list. Continue and enter the host name (e.g. www.my.server). On the next page, you will be presented with another text box; copy/paste this into a new file and save locally as my.server.pem. In some instances further verification is necessary; you can download certificates from the Toolbox|Retrieve Certificates once you get the confirmation email.
Installing the key and certificate on the server
Once you have both the certificate and the key from StartSSL, you need to remove the password (you did write it down/remember it right?) from the key. Actually you don’t need to remove it, and it is technically more secure not to, but in which case you must supply the key password to Apache every time it starts. A right royal pain in the arse. To remove the password from the key, you can use the following command:
openssl rsa -in my.server.key -out my.server.key
Now the key and certificate must be copied to the openSSL directories. Note that on distros other than Ubuntu the openSSL directories may be different.
sudo cp my.server.key /etc/ssl/private/my.server.key sudo cp my.server.pem /etc/ssl/certs/my.server.pem
Lastly, ensure that the certificate and key have appropriate ownership and permissions.
sudo chown root.www-data /etc/ssl/private/my.server.key sudo chown root.www-data /etc/ssl/certs/my.server.pem sudo chmod 440 /etc/ssl/private/my.server.key sudo chmod 440 /etc/ssl/certs/my.server.pe
Configuring Apache
Firstly, ensure that your apache installation has the ssl module enabled:
sudo a2enmod ssl
Setting up the virtual host if fairly simple. Firstly copy the default ssl config to create a new virtual host.
cd /etc/apache2/sites-available sudo cp default-ssl my.server
Edit the my.server file as follows (changes highlighted in bold). Remember you need to run your editor as root.
<IfModule mod_ssl.c>
<VirtualHost _default_:443>
ServerAdmin webmaster@localhost
ServerName www.my.server
DocumentRoot /var/www/default
<Directory />
Options FollowSymLinks
AllowOverride None
</Directory>
<Directory /var/www/default>
Options Indexes FollowSymLinks MultiViews
AllowOverride None
Order allow,deny
allow from all
</Directory>
ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
<Directory "/usr/lib/cgi-bin">
AllowOverride None
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Order allow,deny
Allow from all
</Directory>
ErrorLog ${APACHE_LOG_DIR}/error-default.log
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
LogLevel warn
CustomLog ${APACHE_LOG_DIR}/access-default.log combined
Alias /doc/ "/usr/share/doc/"
<Directory "/usr/share/doc/">
Options Indexes MultiViews FollowSymLinks
AllowOverride None
Order deny,allow
Deny from all
Allow from 127.0.0.0/255.0.0.0 ::1/128
</Directory>
# SSL Engine Switch:
# Enable/Disable SSL for this virtual host.
SSLEngine on
# A self-signed (snakeoil) certificate can be created by installing
# the ssl-cert package. See
# /usr/share/doc/apache2.2-common/README.Debian.gz for more info.
# If both key and certificate are stored in the same file, only the
# SSLCertificateFile directive is needed.
SSLCertificateFile /etc/ssl/certs/my.server.pem
SSLCertificateKeyFile /etc/ssl/private/my.server.key
# Server Certificate Chain:
# Point SSLCertificateChainFile at a file containing the
# concatenation of PEM encoded CA certificates which form the
# certificate chain for the server certificate. Alternatively
# the referenced file can be the same as SSLCertificateFile
# when the CA certificates are directly appended to the server
# certificate for convinience.
#SSLCertificateChainFile /etc/apache2/ssl.crt/server-ca.crt
# Certificate Authority (CA):
# Set the CA certificate verification path where to find CA
# certificates for client authentication or alternatively one
# huge file containing all of them (file must be PEM encoded)
# Note: Inside SSLCACertificatePath you need hash symlinks
# to point to the certificate files. Use the provided
# Makefile to update the hash symlinks after changes.
#SSLCACertificatePath /etc/ssl/certs/
#SSLCACertificateFile /etc/apache2/ssl.crt/ca-bundle.crt
# Certificate Revocation Lists (CRL):
# Set the CA revocation path where to find CA CRLs for client
# authentication or alternatively one huge file containing all
# of them (file must be PEM encoded)
# Note: Inside SSLCARevocationPath you need hash symlinks
# to point to the certificate files. Use the provided
# Makefile to update the hash symlinks after changes.
#SSLCARevocationPath /etc/apache2/ssl.crl/
#SSLCARevocationFile /etc/apache2/ssl.crl/ca-bundle.crl
# Client Authentication (Type):
# Client certificate verification type and depth. Types are
# none, optional, require and optional_no_ca. Depth is a
# number which specifies how deeply to verify the certificate
# issuer chain before deciding the certificate is not valid.
#SSLVerifyClient require
#SSLVerifyDepth 10
# Access Control:
# With SSLRequire you can do per-directory access control based
# on arbitrary complex boolean expressions containing server
# variable checks and other lookup directives. The syntax is a
# mixture between C and Perl. See the mod_ssl documentation
# for more details.
#<Location />
#SSLRequire ( %{SSL_CIPHER} !~ m/^(EXP|NULL)/ \
# and %{SSL_CLIENT_S_DN_O} eq "Snake Oil, Ltd." \
# and %{SSL_CLIENT_S_DN_OU} in {"Staff", "CA", "Dev"} \
# and %{TIME_WDAY} >= 1 and %{TIME_WDAY} <= 5 \
# and %{TIME_HOUR} >= 8 and %{TIME_HOUR} <= 20 ) \
# or %{REMOTE_ADDR} =~ m/^192\.76\.162\.[0-9]+$/
#</Location>
# SSL Engine Options:
# Set various options for the SSL engine.
# o FakeBasicAuth:
# Translate the client X.509 into a Basic Authorisation. This means that
# the standard Auth/DBMAuth methods can be used for access control. The
# user name is the `one line' version of the client's X.509 certificate.
# Note that no password is obtained from the user. Every entry in the user
# file needs this password: `xxj31ZMTZzkVA'.
# o ExportCertData:
# This exports two additional environment variables: SSL_CLIENT_CERT and
# SSL_SERVER_CERT. These contain the PEM-encoded certificates of the
# server (always existing) and the client (only existing when client
# authentication is used). This can be used to import the certificates
# into CGI scripts.
# o StdEnvVars:
# This exports the standard SSL/TLS related `SSL_*' environment variables.
# Per default this exportation is switched off for performance reasons,
# because the extraction step is an expensive operation and is usually
# useless for serving static content. So one usually enables the
# exportation for CGI and SSI requests only.
# o StrictRequire:
# This denies access when "SSLRequireSSL" or "SSLRequire" applied even
# under a "Satisfy any" situation, i.e. when it applies access is denied
# and no other module can change it.
# o OptRenegotiate:
# This enables optimized SSL connection renegotiation handling when SSL
# directives are used in per-directory context.
#SSLOptions +FakeBasicAuth +ExportCertData +StrictRequire
<FilesMatch "\.(cgi|shtml|phtml|php)$">
SSLOptions +StdEnvVars
</FilesMatch>
<Directory /usr/lib/cgi-bin>
SSLOptions +StdEnvVars
</Directory>
# SSL Protocol Adjustments:
# The safe and default but still SSL/TLS standard compliant shutdown
# approach is that mod_ssl sends the close notify alert but doesn't wait for
# the close notify alert from client. When you need a different shutdown
# approach you can use one of the following variables:
# o ssl-unclean-shutdown:
# This forces an unclean shutdown when the connection is closed, i.e. no
# SSL close notify alert is send or allowed to received. This violates
# the SSL/TLS standard but is needed for some brain-dead browsers. Use
# this when you receive I/O errors because of the standard approach where
# mod_ssl sends the close notify alert.
# o ssl-accurate-shutdown:
# This forces an accurate shutdown when the connection is closed, i.e. a
# SSL close notify alert is send and mod_ssl waits for the close notify
# alert of the client. This is 100% SSL/TLS standard compliant, but in
# practice often causes hanging connections with brain-dead browsers. Use
# this only for browsers where you know that their SSL implementation
# works correctly.
# Notice: Most problems of broken clients are also related to the HTTP
# keep-alive facility, so you usually additionally want to disable
# keep-alive for those clients, too. Use variable "nokeepalive" for this.
# Similarly, one has to force some clients to use HTTP/1.0 to workaround
# their broken HTTP/1.1 implementation. Use variables "downgrade-1.0" and
# "force-response-1.0" for this.
BrowserMatch "MSIE [2-6]" \
nokeepalive ssl-unclean-shutdown \
downgrade-1.0 force-response-1.0
# MSIE 7 and newer should be able to use keepalive
BrowserMatch "MSIE [17-9]" ssl-unclean-shutdown
</VirtualHost>
</IfModule>
Of course, if your virtual host requires any other changes then make them now. Then it is just a case of enabling the virtual host and restarting apache.
sudo a2ensite my.server sudo /etc/init.d/apache2 restart
All being well, your server should now be available over SSL. If the server fails to start, check the error logs for details.