Secure Web Server with Client Certificate Authentication and Access Control Feature

Secure access to a web server can be enhanced by requiring a client to present its digital certificate.

A certificate of a subject (client/servers) is a document that contains the information about the subject, the public key of the sender, valid period of the certificate, the issuer (Certificate Authority (CA) that signed the certificate), and the certificate signature. Note that the subject field and public key information are sent by the requester. The other fields are filled in by the CA. The certificates are posted on CA or sender sites.

In Public Key Infrastructure (PKI), there are organizations called Certificate Authorities (CA), which "sign" or certify the certificate requests sent in by others and return the signed certificate (digital certificates). CA’s are also responsible for revoking the certificates and maintaining a certificate revoke list (CRL).

The Public Key Infrastructure utilizes Public Key cryptography which was first proposed by Diffie and Hellman in 1976. Public Key cryptography uses a pair of keys; one public key to be distributed to other communicating parties, and one private key that must be protected and hidden. Data that is encrypted by one key can only be decrypted by the other key of the pair.

In order to authenticate oneself, one can encrypt a known text with one’s private key and send the cipher (encrypted text) to others. The receiver can then use the public key (downloaded from the CA or sender’s website) of the sender to decrypt the encrypted text.

To encrypt the text and only allow a receiver to see it, the sender encrypts the text with the receiver’s public key and sends the cipher text. Only the receiver with the corresponding private key can decipher the cipher text.

For more information about how digital certificates can be used to authenticate users/servers, see Apache document on SSL/TLS Strong Encryption at http://cs.uccs.edu/manual/ssl/ssl_intro.html.

Signing of a Certificate by a CA

In order to sign a certificate, the CA takes all the fields of the certificate, except the last field , and generates the message digest (hash). The CA then encrypts (signs) the message digest using the CA's private key. The resulting encrypted/signed message digest is called the signature. The signature fills the last field of the certificate.

A variety of methods are available for generating the hash, for example MD5, SHA1, SHA-256 etc. However, MD5 is vulnerable and Federal Agencies are urging the phasing out of SHA1. Therefore, we should refrain from using MD5 and use SHA-256 if possible, if not we should at least use SHA1.

How can one prove a certificate is indeed signed by a CA?

The issuer field indicates the CA identity.
The receiver can use the issuer information to locate the related CA certificate. Most browsers come with certificates of known CA’s.
Extract the public key of the CA from the CA certificate.
Decrypt the signed/encrypted message digest (signature) in the last field of the certificate by using the public key.
Generate the message digest independently similar to what the CA did for the sender’s certificate. Apply the message digest function specified in the 3rd field of the certificate.
Compare the independently generated message digest with the decrypted one. If they are the same, then the certificate is indeed signed by the CA.

The various fields of an X.509 certificate are shown at http://cs.uccs.edu/~cs591/crypto/basicCrypto.ppt#57

Example of a Server Certificate signed by a CA

Certificate:

Data:

Version: 3 (0x2)

Serial Number: 1 (0x1)

Signature Algorithm: sha1WithRSAEncryption

Issuer: C=US, ST=Colorado, O=UCCS, OU=Computer Science, CN=CAfc6/emailAddress=ca@fc6.csnet.uccs.edu

Validity

Not Before: Dec 22 18:52:38 2006 GMT

Not After : Dec 22 18:52:38 2007 GMT

Subject: C=US, ST=Colorado, L=Colorado Springs, O=UCCS, OU=Computer Science, CN=fc6.csnet.uccs.edu/emailAddress=webmaster@fc6.csnet.uccs.edu

Subject Public Key Info:

Public Key Algorithm: rsaEncryption

RSA Public Key: (1024 bit)

Modulus (1024 bit):

00:cc:91:db:ea:95:c6:d3:03:75:cd:74:b5:58:28:

b7:df:e5:33:4b:82:53:90:b0:98:5f:14:0b:d1:1a:

44:e4:41:0b:e8:59:f6:f9:d1:26:6a:d9:25:a5:ac:

8e:9d:f0:cd:65:f2:3a:13:b7:37:e2:82:3f:02:e4:

fd:f6:0b:eb:4d:27:97:2b:ab:74:07:8d:fa:0c:4b:

27:ea:c8:78:f6:1e:60:b9:fc:5f:30:0f:8f:02:4b:

d4:d1:b4:bc:a1:bb:d6:e9:dd:78:2e:76:28:21:b5:

5b:76:88:f7:cd:d3:40:26:07:33:2e:95:71:09:e1:

b4:5f:b2:95:99:fd:30:17:49

Exponent: 65537 (0x10001)

X509v3 extensions:

X509v3 Basic Constraints: 

CA:FALSE

Netscape Comment: 

OpenSSL Generated Certificate

X509v3 Subject Key Identifier: 

CA:D9:9B:01:D2:9C:15:39:96:62:53:29:D6:6E:D8:B8:62:9D:A0:BD

X509v3 Authority Key Identifier: 

keyid:DB:B6:B7:15:40:C4:7B:14:AE:F6:CB:A9:DF:44:C3:1E:39:AE:E0:DD


Signature Algorithm: sha1WithRSAEncryption

69:a4:15:98:77:7e:fb:38:88:c3:a0:2e:d8:2b:24:51:50:2c:

cd:dc:a7:56:e0:f5:f3:01:73:47:b2:67:69:4b:94:28:e9:86:

51:fd:e0:2f:a0:30:8a:0d:0c:10:3d:5c:d5:4a:53:df:ea:0c:

38:49:61:1b:92:61:fe:7f:96:bb:65:f4:f9:14:40:52:7d:aa:

8c:0d:07:e1:06:aa:fb:bf:72:6f:7c:d1:68:6e:78:d6:30:7c:

6b:f0:b9:ce:57:5b:f9:d2:cc:df:2c:42:f3:e0:42:cf:0b:5e:

57:ff:72:ac:4a:2b:b9:ac:df:b7:23:80:ea:e4:37:01:b3:13:

9f:73

Here is a bundle of X.509 certificates of public Certificate Authorities used in Fedora Core 4. It is located in /etc/pki/tls/cert.pem. It was generated from the Mozilla root CA list.

"The binary format of a certificate is defined using the ASN.1 notation [ X208] [PKCS]. This notation defines how to specify the contents, and encoding rules define how this information is translated into binary form. The binary encoding of the certificate is defined using Distinguished Encoding Rules (DER), which are based on the more general Basic Encoding Rules (BER). For those transmissions which cannot handle binary, the binary form may be translated into an ASCII form by using Base64 encoding [MIME]. This encoded version is called PEM encoded (the name comes from "Privacy Enhanced Mail"), when placed between begin and end delimiter lines" (cited in http://cs.uccs.edu/manual/ssl/ssl_intro.html) as follows:

The certificates and keys generated by Openssl are saved, by default, in pem file format. Utilities are available to convert then to different formats, such as pkcs12 format which can be imported to Netscape/Firefox browsers.

To learn how certificates and SSL are used to enhance secure web access, see the brief description in http://httpd.apache.org/docs-2.0/ssl/ssl_faq.html#aboutcerts

Mod_SSL

The current apache distribution supports secure web server using mod_ssl module. The mod_ssl v1 package was initially created in April 1998 by Ralf S. Engelschall via porting Ben Laurie's Apache-SSL 1.17 source patches for Apache 1.2.6 to Apache 1.3b6.

The configuration file ssl.conf is /etc/httpd/conf.d/ssl.conf (See Apache SSL/TLS Encryption for more details. http://httpd.apache.org/docs-2.0/ssl/) The SSLCipherSuite specifies the order of ciphers the client is permitted to negotiate: http://httpd.apache.org/docs-2.0/mod/mod_ssl.html#sslciphersuite

The FC6 apache distribution uses

SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2: +EXP

You can see the resulting cipher list by executing

"openssl ciphers -v 'ALL:!ADH:!EXPORT56:RC4+RSA: +HIGH:+MEDIUM:+LOW:+SSLv2:+EXP'

Testing https: $ openssl s_client -connect localhost:443 -state -debug GET / HTTP/1.0

There is command line test tool called curl, http://curl.haxx.se/download.html
Curl is a command line tool for transferring files with URL syntax, supporting FTP, FTPS, HTTP, HTTPS, GOPHER, TELNET, DICT, FILE and LDAP. Curl supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading, kerberos, HTTP form based upload, proxies, cookies, user+password authentication, file transfer resume, http proxy tunneling and a busload of other useful tricks. http://curl.haxx.se/docs/sslcerts.html. Add the CA cert for your server to the existing default CA cert bundle. The default path of the CA bundle installed with the curl package is: /usr/local/share/curl/curl-ca-bundle.crt, which can be changed by running configure with the --with-ca-bundle option pointing out the path of your choice. Using OpenSSL to create new CA (private key and certificate), to create new server private key and certificate request, and to have the new CA sign the server certificate.

The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, full featured, and Open Source toolkit implementing the Secure Socket Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general pupose cryptography library.

Exercise in Creating and Using Certificates

Here, we will explore how to configure apache web server to accept SSL connection and to allow access to certain directories by requiring the client to present their certificate. In the following, we will use the FC6 virtual machine to illustrate the process. We will use the Openssl software package to:

Create a self-signed Certificate Authority certificate/private key.
Create a web server certificate request and private key, and sign the certificate using the CA private key.
Generate a client certificate request and private key, and to sign the client certificate using CA private key.

On FC6 and FC4 there is a CA shell script for creating self-signed CA, server/client requests, and for signing the certificate request. The CA shell can be found in /etc/pki/tls. In FC3, the CA shell can be found in /usr/shar/ssl/misc.

CA -newca will set up the right information for the CA.
CA -newreq will generate a certificate request.
CA -sign will sign the generated request and output.

The CA script utilizes openssl commands. A brief description on the related commands which are used can be found at http://www.openssl.org/docs/HOWTO/certificates.txt
The openssl utility reads the openssl.cnf configuration file to find out the location of the default settings for the subject fields and default CA private key and certificate.

For both FC6 and FC4, openssl.cnf is saved in /etc/pki/tls/. For FC3, openssl.cnf is saved in /usr/share/ssl/.

Edit the distinguished name section of openssl.cnf by replacing the attributes in red:

[ CA_default ]


default_md = sha1

[ req_distinguished_name ]

countryName = Country Name (2 letter code)

countryName_default = US

countryName_min = 2

countryName_max = 2

stateOrProvinceName = State or Province Name (full name)

stateOrProvinceName_default = Colorado

localityName = Locality Name (eg, city)

localityName_default = Colorado Springs

0.organizationName = Organization Name (eg, company)

0.organizationName_default = UCCS

# we can do this but it is not needed normally :-)

#1.organizationName = Second Organization Name (eg, company)

#1.organizationName_default = World Wide Web Pty Ltd

organizationalUnitName = Organizational Unit Name (eg, section)

organizationalUnitName_default = Computer Science
# make sure you remove the # before organizationalUnitName_default in the above lineSave the changes to this file.

CREATE A NEW CA

Here are the detailed steps for creating a new CA.
Use the same password when asked for the pass phrase (password). This makes it easier to remember. It is suggested that you use the same password that you use to login to the FC6 virtual machine.

Enter CAfc6 for the common name and ca@fc6.csnet.uccs.edu for the Email address.

[root@localhost tls]# rm -rf ./../CA

This removes the old certificates/keys/crl in /etc/CA directory and allows us to create a new CA directory. (On FC3, the above directory is in /usr/share/ssl/demoCA.)

   [root@localhost tls]# misc/CA -newca

   CA certificate filename (or enter to create)

   Making CA certificate ...

   Generating a 1024 bit RSA private key

   .............++++++

   .......................++++++

   writing new private key to '../../CA/private/./cakey.pem'

   Enter PEM pass phrase:	XXXXXXXXX

   Verifying - Enter PEM pass phrase:	XXXXXXXXX

   -----

  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) [US]:
   # hit enter for the default choice we specified in openssl.cnf
State or Province Name (full name) [Colorado]:

Locality Name (eg, city) [Colorado Springs]:

Organization Name (eg, company) [UCCS]:

Organizational Unit Name (eg, section) [Computer Science]:

Common Name (eg, your name or your server's hostname) []:CAfc6

Email Address []:ca@fc6.csnet.uccs.edu

CREATING SERVER CERTIFICATE

We use the "CA -newreq" command to create a server certificate request. Enter fc6.csnet.uccs.edu (the domain name used by the web server) for the common name and webmaster@fc6.csnet.uccs.edu for the email address.

If you enter a different common name such as serverfc6, the browser will prompt "You have attempted to establish a connection with fc6.csnet.uccs.edu". However, the security certificate presented belongs to "serverfc6". It is possible, though unlikely that someone may be trying to intercept your communication with this web site.

Here are the steps for creating a server certificate request:

[root@localhost tls]# misc/CA -newreq

   Generating a 1024 bit RSA private key

   .....++++++

   .........++++++

   writing new private key to 'newkey.pem'

   Enter PEM pass phrase: XXXXXXXXX

   Verifying - Enter PEM pass phrase: XXXXXXXXX

   -----

   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) [US]:

   State or Province Name (full name) [Colorado]:

   Locality Name (eg, city) [Colorado Springs]:

   Organization Name (eg, company) [UCCS]:

   Organizational Unit Name (eg, section) [Computer Science]:

   Common Name (eg, your name or your server's hostname) []:fc6.csnet.uccs.edu

   Email Address []:webmaster@fc6.csnet.uccs.edu

   Please enter the following 'extra' attributes

   to be sent with your certificate request

   A challenge password []:

   An optional company name []:

   Request is in newreq.pem, private key is in newkey.pem

Note: In previous versions of Fedora Core, the server certificate and server private key were located in the same newreq.pem file. In that case, it was necessary to remove the private key from the server certificate request, since we did not want to send the server private key to the CA.

Signing the Server Certificate

After the server certificate request is granted, it will be sent to the CA site for signing. The server certificate is located in newreq.pem and the server private key is located in newkey.pem.

In reality, we will attach newreq.pem in an email sent to the CA such as Verisign. Here we will use the same machine as the CA. The CA will perform certain "investigations" on the credentials of the server site based on the type/grade of the certificate issued. The signed certificate will then be returned, typically in PEM format, with instructions on how to install it on the web server.

In our case, we are skipping the certificate request/certificate exchange, since we serve both the role of the CA and the web server admin. The certificate request and signed certificate will all be in the same /etc/pki/tls directory.

We use the command "misc/CA -sign". You will first be asked to enter the pass phrase for decrypting the RSA private key of the CA and then be asked to confirm the signing and commit. The CA saves all the signed certificates in /etc/CA/newcerts. The CA certificate is saved as /etc/CA/cacert.pem. The CA private key is save in /etc/CA/private/cakey.pem.

Here are the detailed steps for signing process:

[root@localhost tls]# misc/CA -sign

   Using configuration from /etc/pki/tls/openssl.cnf

   Enter pass phrase for ../../CA/private/cakey.pem: XXXXXXXXX

   Check that the request matches the signature

   Signature ok

   Certificate Details:

   Serial Number: 1 (0x1)

   Validity

   Not Before: Dec 22 18:52:38 2006 GMT

   Not After : Dec 22 18:52:38 2007 GMT

   Subject:

   countryName               = US

   stateOrProvinceName       = Colorado

   localityName              = Colorado Springs

   organizationName          = UCCS

   organizationalUnitName    = Computer Science

   commonName                = fc6.csnet.uccs.edu

   emailAddress              = webmaster@fc6.csnet.uccs.edu

   X509v3 extensions:

   X509v3 Basic Constraints:

   CA:FALSE

   Netscape Comment:

   OpenSSL Generated Certificate

   X509v3 Subject Key Identifier:

   CA:D9:9B:01:D2:9C:15:39:96:62:53:29:D6:6E:D8:B8:62:9D:A0:BD

   X509v3 Authority Key Identifier:

   keyid:DB:B6:B7:15:40:C4:7B:14:AE:F6:CB:A9:DF:44:C3:1E:39:AE:E0:DD

   


   Certificate is to be certified until Dec 22 18:52:38 2007 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

   Certificate:

   Data:

   Version: 3 (0x2)

   Serial Number: 1 (0x1)

   Signature Algorithm: sha1WithRSAEncryption

   Issuer: C=US, ST=Colorado, O=UCCS, OU=Computer Science, CN=CAfc6/emailAddress=ca@fc6.csnet.uccs.edu

   Validity

   Not Before: Dec 22 18:52:38 2006 GMT

   Not After : Dec 22 18:52:38 2007 GMT

   Subject: C=US, ST=Colorado, L=Colorado Springs, O=UCCS, OU=Computer Science, CN=fc6.csnet.uccs.edu/emailAddress=webmaster@fc6.csnet.uccs.edu

   Subject Public Key Info:

   Public Key Algorithm: rsaEncryption

   RSA Public Key: (1024 bit)

   Modulus (1024 bit):

   00:cc:91:db:ea:95:c6:d3:03:75:cd:74:b5:58:28:

   b7:df:e5:33:4b:82:53:90:b0:98:5f:14:0b:d1:1a:

   44:e4:41:0b:e8:59:f6:f9:d1:26:6a:d9:25:a5:ac:

   8e:9d:f0:cd:65:f2:3a:13:b7:37:e2:82:3f:02:e4:

   fd:f6:0b:eb:4d:27:97:2b:ab:74:07:8d:fa:0c:4b:

   27:ea:c8:78:f6:1e:60:b9:fc:5f:30:0f:8f:02:4b:

   d4:d1:b4:bc:a1:bb:d6:e9:dd:78:2e:76:28:21:b5:

   5b:76:88:f7:cd:d3:40:26:07:33:2e:95:71:09:e1:

   b4:5f:b2:95:99:fd:30:17:49

   Exponent: 65537 (0x10001)

   X509v3 extensions:

   X509v3 Basic Constraints:

   CA:FALSE

   Netscape Comment:

   OpenSSL Generated Certificate

   X509v3 Subject Key Identifier:

   CA:D9:9B:01:D2:9C:15:39:96:62:53:29:D6:6E:D8:B8:62:9D:A0:BD

   X509v3 Authority Key Identifier:

   keyid:DB:B6:B7:15:40:C4:7B:14:AE:F6:CB:A9:DF:44:C3:1E:39:AE:E0:DD

   Signature Algorithm: sha1WithRSAEncryption

   69:a4:15:98:77:7e:fb:38:88:c3:a0:2e:d8:2b:24:51:50:2c:

   cd:dc:a7:56:e0:f5:f3:01:73:47:b2:67:69:4b:94:28:e9:86:

   51:fd:e0:2f:a0:30:8a:0d:0c:10:3d:5c:d5:4a:53:df:ea:0c:

   38:49:61:1b:92:61:fe:7f:96:bb:65:f4:f9:14:40:52:7d:aa:

   8c:0d:07:e1:06:aa:fb:bf:72:6f:7c:d1:68:6e:78:d6:30:7c:

   6b:f0:b9:ce:57:5b:f9:d2:cc:df:2c:42:f3:e0:42:cf:0b:5e:

   57:ff:72:ac:4a:2b:b9:ac:df:b7:23:80:ea:e4:37:01:b3:13:

   9f:73

   

-----BEGIN CERTIFICATE-----

MIIDIjCCAougAwIBAgIBATANBgkqhkiG9w0BAQUFADCBgDELMAkGA1UEBhMCVVMx

ETAPBgNVBAgTCENvbG9yYWRvMQ0wCwYDVQQKEwRVQ0NTMRkwFwYDVQQLExBDb21w

dXRlciBTY2llbmNlMQ4wDAYDVQQDEwVDQWZjNjEkMCIGCSqGSIb3DQEJARYVY2FA

ZmM2LmNzbmV0LnVjY3MuZWR1MB4XDTA2MTIyMjE4NTIzOFoXDTA3MTIyMjE4NTIz

OFowga8xCzAJBgNVBAYTAlVTMREwDwYDVQQIEwhDb2xvcmFkbzEZMBcGA1UEBxMQ

Q29sb3JhZG8gU3ByaW5nczENMAsGA1UEChMEVUNDUzEZMBcGA1UECxMQQ29tcHV0

ZXIgU2NpZW5jZTEbMBkGA1UEAxMSZmM2LmNzbmV0LnVjY3MuZWR1MSswKQYJKoZI

hvcNAQkBFhx3ZWJtYXN0ZXJAZmM2LmNzbmV0LnVjY3MuZWR1MIGfMA0GCSqGSIb3

DQEBAQUAA4GNADCBiQKBgQDMkdvqlcbTA3XNdLVYKLff5TNLglOQsJhfFAvRGkTk

QQvoWfb50SZq2SWlrI6d8M1l8joTtzfigj8C5P32C+tNJ5crq3QHjfoMSyfqyHj2

HmC5/F8wD48CS9TRtLyhu9bp3XgudightVt2iPfN00AmBzMulXEJ4bRfspWZ/TAX

SQIDAQABo3sweTAJBgNVHRMEAjAAMCwGCWCGSAGG+EIBDQQfFh1PcGVuU1NMIEdl

bmVyYXRlZCBDZXJ0aWZpY2F0ZTAdBgNVHQ4EFgQUytmbAdKcFTmWYlMp1m7YuGKd

oL0wHwYDVR0jBBgwFoAU27a3FUDEexSu9sup30TDHjmu4N0wDQYJKoZIhvcNAQEF

BQADgYEAaaQVmHd++ziIw6Au2CskUVAszdynVuD18wFzR7JnaUuUKOmGUf3gL6Aw

ig0MED1c1UpT3+oMOElhG5Jh/n+Wu2X0+RRAUn2qjA0H4Qaq+79yb3zRaG541jB8

a/C5zldb+dLM3yxC8+BCzwteV/9yrEoruazftyOA6uQ3AbMTn3M=

-----END CERTIFICATE-----



Signed certificate is in newcert.pem

The CA will typically email back the server admin with the signed certificate as an attachment.
Here we just rename them.
mv newcert.pem fc6ServerCert.pem
mv newkey.pem fc6ServerPrivateKey.pem

Set up Apache to use the new server certificate and private key

The configuration file for plain httpd server is in /etc/httpd/conf/httpd.conf file; while that of the secure httpd server is in /etc/httpd/conf.d/ssl.conf.
Line 112 of ssl.conf specifies the location of signed server certificate. SSLCertificateFile /etc/pki/tls/certs/localhost.crt

Line 119 of ssl.conf specifies the location of server private key. SSLCertificateKeyFile /etc/pki/tls/private/localhost.key

The above indicates the FC6 by default accessing the certificate and private key in /etc/pki/tls

Note that instead of using .pem as file extension. Apache uses .crt for certificate and .key for key. But they are typically saved with PEM format.

You may not find ssl.crt or ssl.key in /etc/httpd/conf directory.
cd /etc/httpd/conf
cp ssl.crt/server.crt to ssl.crt/server.crt.orig
cp ssl.key/server.key to ssl.key/server.key.orig

If you do not find ssl.crt or ssl,key directories, create them: mkdir ssl.crt ssl.key
Copy the new server certificate and private key.
Assume that we are still in /etc/httpd/conf directory

cp /etc/pki/tls/fc6ServerCert.pem ssl.crt/server.crt
cp /etc/pki/tls/fc6ServerPrivateKey.pem ssl.key/server.key

Edit /etc/httpd/conf.d/ssl.conf replace line 112 and 119 with the following:

SSLCertificateFile /etc/httpd/conf/ssl.crt/server.crt
SSLCertificateKeyFile /etc/httpd/conf/ssl.key/server.key

Edit /etc/hosts to replace the line with 127.0.0.1 with the following:

127.0.0.1 fc6.csnet.uccs.edu fc6 localhost.localdomain localhost

This allows us to resolve the fc6.csnet.uccs.edu domain name locally without checking with the DNS system.

Try to run "service httpd restart"
We will find that the service will fail to restart. By examining the /etc/httpd/logs/ssl_error_log, we will find that apache complains that it does not read in the pass phrase:
[Sun Feb 18 15:28:05 2007][error] Init: Unable to read pass phrase [Hint: key introduced or changed before restart?]
The reason is that the fc6ServerPrivateKey.pem is actually protected by the password phrase, it contains the following content:

The first two lines indicate the private key is encrypted with 3DEC encryption method and 6BC52F8B3C9C2F3E is the encrypted password. If we use newkey.pem directly, the apache server will ask for pass phrase during the configuration time and fails if we use apachectl script. To avoid the problem of entering the pass phrase, we can remove the pass phrase protection on the server private key with the following openssl command.

If we use fc6SserverPrivateKey.pem as server.key directly, the apache web server will ask for pass phrase during the configuration time and fails if we use apachectl script.

To avoid the problem of entering the pass phrase, we can remove the pass phrase protection on the server private key with the following openssl command.

[root@fc4 conf]# cd /etc/httpd/conf/ssl.key

[root@fc4 ssl.key]# cp server.key server.key.new

[root@fc4 ssl.key]# openssl rsa -in server.key.new -out server.key

Enter pass phrase for server.key.new:
  writing RSA key

This removes the first two lines from the file as shown below:

Now it is important to protect the server.key by "chmod 700 server.key"
Restart the web server with

"service httpd restart"

Start the Firefox web browser on FC6. When we type in https://fc6.csnet.uccs.edu/, we should see the prompt for allowing us to examine the server certificate. Click "Examine Certificate" to see the server certificate.

Hit Ctrl-Alt to exit cs591fc6 and click the title bar of cs591fc6 to make cs591fc6 as an active window.
Use Control-Alt-PrtSc to capture the active window (cs591fc6) with the server certificate.
Here is the capture image of the server certificate on fc6.csnet.uccs.edu.
fc4 server cert

Save your captured image in your CS Unix web site and email me the url.
Here is the captured image of the server certificate on fc6.csnet.uccs.edu.

Here is how IE Browser displays the Athena.uccs.edu server certificate

Note that on a real server such as Athena.uccs.edu, when configuring with a secure web server, you need to open the firewall to allow secure web access, otherwise, you will still get the "page not found" error.

To open the customized firewall access, you can use the "lokkit" command to bring up the firewall configuration menu. The select "customize" menuitem and "secure www (https)".

Set up Apache to authenticate users based on the provided client certificate.

Add the following directives to /etc/httpd/conf/httpd.conf

SSLVerifyClient none


<Directory /var/www/html/secure>

SSLVerifyClient require

SSLVerifyDepth 5

SSLCACertificateFile conf/ssl.crt/ca.crt

SSLCACertificatePath conf/ssl.crt

SSLOptions +FakeBasicAuth

SSLRequireSSL

AuthName "UCCS CS Department"

AuthType Basic

AuthUserFile /etc/httpd/conf/httpd.passwd

require valid-user

</Directory>

Add the following line to the /etc/httpd/conf/httpd.passwd

/C=US/ST=Colorado/L=Colorado Springs/O=UCCS/OU=Computer Science/CN=chow/emailAddress=chow@cs.uccs.edu: xxj31ZMTZzkVA

You should replace chow with your own CN and chow@cs.uccs.edu with your own email address.
The encrypted password xxj31ZMTZzkVA should not be changed. All entries in httpd.passwd should contain the same fake password. No space after it. If you do not see httpd.passwd, create one.

The above client certificate verification using FakeBasicAuth option is implemented in line 1836 of ssl_hook_UserCheck() of ssl_engine_kernel.c (http://cs.uccs.edu/~cs591/httpd-2.0.54/modules/ssl/ssl_engine_kernel.c)

Note that the string "xxj31ZMTZzkVA" is used as the password in the user file and it is just the crypted variant of the word "password".

Since we specify in the above "SSLCACertificateFile conf/ssl.crt/ca.crt" to use the public key in this CA certificate to verify the client certificate, we need to copy the CA certificate from /usr/share/sshl. Use the following command:

cp /etc/CA/cacert.pem /etc/httpd/conf/ssl.crt/ca.crt

Make sure to include all subject field of the client certificate. The example in SSL-how-to does not include /ST, /O, and /emailAddress fields and does not seem to work with apache2.0.52 on fc3.

Create a secure directory under /var/www/html.
With index.html contains:
<h1> This is a secure area only accessible via client certificate and subject field match the httpd.passwd list.</h1>

Set up Client browser to use the new client certificate.

cd /etc/pki/tls
Use misc/CA -newreq and misc/CA -sign to create clientCert.pem and clientPrivateKeyCR.pem. Similar to the creation of server certificate. Use your login name as Common Name. and your uccs email address as emailAddress.

misc/CA -newreq

misc/CA -sign

cp newcert.pem clientCert.pem

cp newkey.pem clientKey.pem

Since Netscape or Firefox only accept pkcs12 format. We use pkcs12 utility command of openssl to export the client certificate with the format. openssl pkcs12 -export -in clientCert.pem -inkey clientKey.pem -out Client.p12

[root@localhost tls]# openssl pkcs12 -export -in clientCert.pem -inkey clientKey.pem -out <yourLogin>Client.p12

Enter pass phrase for clientKey.pem:XXXXXXX

Enter Export Password: YYYYYYYY

Verifying - Enter Export Password: YYYYYYYY

You will be asked to enter the pass phrase and export password. The export password will be asked for when we install on client browser.

Note that here we are exporting both the private key and the client certificate, all in the same file protected by the export password. Make sure you carry/transmit them in a secure manner.

Besides creating a client certificate with your login name.

Repeat the above process and create a client certificate with cs591 as CN and cs591@cs.uccs.edu as email address field. It will allow us to check whether the server rejects the access when presented with an client certificate not in the httpd.passwd list.

Restart the web server with "service httpd restart"

Copy <yourLogin>Client.p12 and cs591Client.p12 to root directory. In real word, the user will transfer password protected the client certificate to the local machine for installation.

Import your client certificate to your browser.

On firebox browser, select Edit | Preference
Bring up Preference dialog window. Select Advanced and then Security Tag.
Click view Certificates
Click import and chose Client.p12 file. It is in /etc/pki/tls directory.
You will be asked to enter the software security device password (i.e., the export password) and the new password used to encrypt certificate backup on the browser. Use the same password we have being using.

You will be asked to enter a password for encrypting the certificate backup.

You will get "Successfully restored your security certificate(s) and private key(s). Click OK.

Click OK on Certificate Management.

Repeat the above to set up the cs591 client certificate.Make sure select the "ask every time" as client certficate selection option. Otherwise a client certificate will be selected automatically for you.

Let us now access the https://fc6.csnet.uccs.edu/secure/ and take a snapshot of the browser. Note that the browser will prompt the user to select client certificate as it is shown with "User Identification Request" window on the right side of the screendump.

Instead of the cs591 client, you should choose your client certificate. Click the drop down list to select the right one.
Take a snapshort of the client certifciate presented by the browser.You should see the secure web page displayed.

If we set up fc6se with the 2nd network interface and assign 10.0.0.56, we will be able to access the fc6.csnet.uccs.edu server from xpvm1 virutal machine. The following is the step for setting up IE with personal ceritificate. This is optional for your hw3.

On IE, we can import the personal certificate by selecting Tools | Internet Options and select Content tab and certificates button.
Select personal tab and import button.
Certificate import wizard will appear. Click browse and select the person certificate file such as chowClient.p12. You may need to change the file type from X509 to personal information exchange (*.pfx, *.p12) to see you p12 file.
Click next. Enter the password for protecting the private key. click next, click finish. The certificate is install.
You can see it installed similar to this