$ telnet localhost 80 GET / HTTP/1.0
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Cookbook: SSL, TLS and certificates
This section answers some general questions and details the procedure to generate SSL keys.
General questions
Can the same server provide HTTP and HTTPS?
Yes. HTTP and HTTPS use different server ports. The former binds to port 80 and the latter to port 443, so there is no conflict between them. To provide HTTPS you will need matching certificates.
Keep in mind that to have one of your virtual servers with HTTPS enabled you will need to configure HTTPS settings for all of them.
Which port does HTTPS use?
HTTPS can run on any port, but the standards specify port 443. That's where any HTTPS compliant browser will look by default. You can change that by specifying another port in the URL. For example, https://example.com:8080/ would look for an HTTPS server on port 8080.
How to manually test HTTP/HTTPS?
HTTP can easily be tested like this:
For HTTPS it is not so easy because of the SSL protocol between TCP and HTTP. However you can do a similar check with the help of OpenSSL's s_client command.
$ openssl s_client -connect localhost:443 -state -debug GET / HTTP/1.0
You will receive detailed information about the SSL handshake before the actual HTTP response.
A more general command line client is probably a better choice. cURL deals with both HTTP and HTTPS, and performs a bunch of other interesting stuff.
$ curl http://localhost/ $ curl https://localhost/
Private keys and Certificates overview
First some terminology:
-
RSA private key file: a digital file that can be used to decrypt messages sent to you. It has a public component that must be distributed (via your Certificate file) to allow people to encrypt those messages.
-
CSR, or Certificate Signing Request: a digital file containing your public key and your name. It is sent to a Certifying Authority (CA) that will convert sign it to conert it into a real Certificate.
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Certificate: contains your RSA public key and name, the name of the CA, and is digitally signed by the CA. A browser that knows the CA can verify the signature and obtain your RSA public key, which can be used to send messages which only you can decrypt.
Does the startup between a non-SSL and an SSL-aware web server differ?
Yes. Although in essence it is exactly the same, if you have a passphrase on your SSL private key file, a startup dialog will asks you to enter it. This can be problematic if the web server needs to be started automatically. In this case, the passphrase can be removed from your private key at the cost of erasing a security layer, wich brings additional security risks.
Does Cherokee offer any help for Certificate Generation?
Yes. A script is provided to assit you with Certificate Generation.
Just locate the contrib subdirectory and type:
make-cert.sh
And follow the instructions. It will generate the required files, but you will have to install them manually.
It has been tested and has worked fine every time, but if you don't find the script or it doesn't work for you can always follow the rest of the procedure described in this recipe to manually generate the certificates.
Locate CA.pl or CA.sh
-
On Debian or Ubuntu those are usually located under /usr/lib/ssl/misc/
-
On MacOS X, you will find them in /System/Library/OpenSSL/misc/
In any other case `find / -iname CA.pl -print` will help you to locate it.
Create a new CA
$ /usr/lib/ssl/misc/CA.pl -newca
CA certificate filename (or enter to create) <press enter>
Making CA certificate ...
Generating a 1024 bit RSA private key
.............++++++
.......................................++++++
writing new private key to './demoCA/private/cakey.pem'
Enter PEM pass phrase: <type the secret phrase again>
Verifying - Enter PEM pass phrase: <type the secret phrase again>
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:ES
State or Province Name (full name) [Some-State]:.
Locality Name (eg, city) []:.
Organization Name (eg, company) [Internet Widgits Pty Ltd]:Cherokee Team
Organizational Unit Name (eg, section) []:<Enter>
Common Name (eg, YOUR name) []:Cherokee Certificate Master
Email Address []:[email protected]
Generate a certificate request
$ /usr/lib/ssl/misc/CA.pl -newreq
Generating a 1024 bit RSA private key
.....................................++++++
...++++++
writing new private key to 'newreq.pem'
Enter PEM pass phrase: <anothe phrase>
Verifying - Enter PEM pass phrase: <repeat it>
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:ES
State or Province Name (full name) [Some-State]:.
Locality Name (eg, city) []:.
Organization Name (eg, company) [Internet Widgits Pty Ltd]:Cherokee web server
Organizational Unit Name (eg, section) []:.
Common Name (eg, YOUR name) []:www.cherokee-project.com
Email Address []:[email protected]
Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []: <Enter>
An optional company name []: <Enter>
Request (and private key) is in newreq.pem
Sign the certificate request
$ /usr/lib/ssl/misc/CA.pl -sign:
Using configuration from /usr/lib/ssl/openssl.cnf
Enter pass phrase for ./demoCA/private/cakey.pem:
Check that the request matches the signature
Signature ok
Certificate Details:
Serial Number: 1 (0x1)
Validity:
Not Before: Aug 17 13:12:44 2003 GMT
Not After : Aug 16 13:12:44 2004 GMT
Subject:
countryName = ES
organizationName = Cherokee web server
commonName = www.cherokee-project.com
emailAddress = [email protected]
X509v3 extensions:
X509v3 Basic Constraints:
CA:FALSE
Netscape Comment:
OpenSSL Generated Certificate
X509v3 Subject Key Identifier:
14:6A:45:66:A2:EB:73:74:5A:C5:68:80:50:D5:48:94:DD:ED:25:F7
X509v3 Authority Key Identifier:
keyid:9E:E0:E2:6E:1B:02:17:F2:72:C9:0D:E3:DA:C9:E1:8F:CE:BC:6E:A2
DirName:/C=ES/ST=Madrid/L=Madrid/O=Cherokee Team/CN=Cherokee Certificate Master/[email protected]
serial:00
Certificate is to be certified until Aug 16 13:12:44 2004 GMT (365 days)
Sign the certificate? [y/n]:y
1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated
Signed certificate is in newcert.pem
Self signed certificates
It is another way to generate certificate files. Ramon Pons sent this little script to create self signed certificates::
#!/bin/sh
CERTNAME=cherokee.pem
openssl req -days 1000 -new -x509 -nodes -out $CERTNAME -keyout $CERTNAME
chmod 600 $CERTNAME
openssl verify $CERTNAME
if [ $? != 0 ]; then
\mv $CERTNAME $CERTNAME.not_valid
fi
You can see that, in essence, it issues the folowing command:
$ openssl req -new -x509 -nodes -out server.crt -keyout server.key
Which would produce a couple of files: the SSL Certificate File (server.crt) and the SSL Certificate key file (server.key).
This server.key does not have any passphrase. To add a passphrase to the key, you should run the following command, and enter & verify the passphrase as requested.
$ openssl rsa -des3 -in server.key -out server.key.new $ mv server.key.new server.key
You should probably backup the key file and the entered passphrase in a secure location.
Pass-phrase issues
As noted above, if you have a pass-phrase on your SSL private key file, the web-server start up will remain on hold until you enter it. Here is the information needed to changeit or even removing it, but bare in minda the security implications.
How to change the pass-phrase on a private key file?
Simply read it with the old pass-phrase and write it again, specifying a new pass-phrase. This can be done withe these commands:
$ openssl rsa -des3 -in server.key -out server.key.new $ mv server.key.new server.key
How to get rid of the pass-phrase?
The RSA private key inside the server.key file is stored in encrypted format for security reasons. The pass-phrase is needed to decrypt this file, so it can be read and parsed. Thus, removing it removes a layer of security from the web server. It is advised to keep a backup copy of the original file before proceeding.
$ cp server.key server.key.org $ openssl rsa -in server.key.org -out server.key $ chmod 400 server.key
Since the server.key now contains an unencrypted copy of the key, if anyone gets it they will be able to impersonate you on the net.
Verifying that a private key matches its Certificate
To view the Certificate and the key run the commands:
$ openssl x509 -noout -text -in server.crt $ openssl rsa -noout -text -in server.key
The modulus and the public exponent portions in the key and the Certificate must match. It is difficult to visually check that the long modulus numbers are the same, so this approach can be used instead to obtain the numbers to compare (though it is mathematically less rigorous).
$ openssl x509 -noout -modulus -in server.crt | openssl md5 $ openssl rsa -noout -modulus -in server.key | openssl md5
To check to which key or certificate a particular CSR belongs you can perform the same calculation on the CSR as follows:
$ openssl req -noout -modulus -in server.csr | openssl md5
