[Cialug] Apache - SSL Proxy - Name Based VirtualHost Problem

chris chris at ia.gov
Fri Oct 19 16:26:38 CDT 2007


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You can accomplish what ProxyPreserveHost does in 1.3.x by cheating with
a host file entry.  Example below:


On the reverse proxy.

host file entry:
127.0.0.1  mysite.com

httpd.conf:

Servername  mysite.com
ProxyPass  / 	http://mysite.com


That'll do the same thing.


You really should move to 2.2.x.  Please, I'm begging.  There have been
no enhancements to 1.3.x for years.  It's the equivalent of installing
RedHat 7.2 or Slackware 5 for a production server today.  You wouldn't
do that would you? :)

If you mean the do I do privilege separation this way?  Yes, I do.  It
works very well.  I also terminate SSL at the proxy and pass http in as
you are doing in many cases.


Worthy of note, with the advent of wildcard certificates you may now run
 multiple SSL sites on the same IP with Apache given that they all share
the same domain.  eg. *.somedomain.tld.


chris



Claus wrote:
> Great suggestion Chris.  It sounds like you identified the problem.  The
> ProxyPass directive takes the new specified server domain name and uses
> it in the host header.  Unfortunately I'm using Apache 1.3.29 and the
> ProxyPreserveHost directive isn't part of Apache until 2.0.31. It's the
> default with the OpenBSD default install and so far I have tried to stay
> with that. :(
> 
> Rethinking the whole issue I probably just use the RewriteRule of port
> 80 and let the clients connect directly to port 8030 of the final Apache
> server.
> 
> Advantages:
>  - each domain can have their individual certificate
> 
> Disadvantages:
>  - need to update firewall rules
>  - client can't easily use https:// address.
> 
> I really thought the proxy would be a neat solution.  Does anybody use
> proxy in such a way?  Should I continue considering it and if so are
> there other (asides Apache 2.0) that I should consider?
> 
>   Claus
> 
> On 10/19/2007 3:27 PM, chris wrote:
> On quick glance I'd say you're loosing your host header.  Try adding in
> a "ProxyPreserveHost On" in the Main Proxy and in the Second Proxy as
> well.
> 
> The default vhost is always the first defined vhost, so in named based
> hosting if nothing matches, you get the the first one apache found when
> parsing the config.
> 
> BTW, what you are doing we call real privilege separation.  Rici Lake
> recently wrote a nice howto on it here:
> http://wiki.apache.org/httpd/DifferentUserIDsUsingReverseProxy
> 
> You might find some useful stuff in it.
> 
> cheers!
> 
> chris at ia.gov
> 
> 
> Claus wrote:
>>>> I'm virtualizing the Apache servers, so each server is chrooted to their
>>>> directory and PHP scripts from one server can't access the other
>>>> servers.  So, on the server I'm running one main Apache instance that
>>>> listens to the publicly accessible port 80.  The other Apache instances
>>>> listen to local host only on their respective port (eg. 8010, 8020).  To
>>>> do this, and it does work, I use the following directives for the main
>>>> (proxy) Apache instance:
>>>>
>>>> <Directory proxy:http://localhost:8010/>
>>>>   Order deny,allow
>>>>   Allow from all
>>>> </Directory>
>>>> <VirtualHost *:80>
>>>>   ServerName host1.example.com
>>>>   ProxyPass / http://localhost:8010/
>>>>   ProxyPassReverse / http://localhost:8010/
>>>> </VirtualHost>
>>>>
>>>> <Directory proxy:http://localhost:8020/>
>>>>   Order deny,allow
>>>>   Allow from all
>>>> </Directory>
>>>> <VirtualHost *:80>
>>>>   ServerName host2.example.com
>>>>   ProxyPass / http://localhost:8020/
>>>>   ProxyPassReverse / http://localhost:8020/
>>>> </VirtualHost>
>>>>
>>>>
>>>> The next step was to add an SSL host, which successfully worked by
>>>> adding these directives:
>>>>
>>>> <Directory proxy:http://localhost:8030/>
>>>>   SSLRequireSSL
>>>>   Order deny,allow
>>>>   Allow from all
>>>> </Directory>
>>>> <VirtualHost *:80>
>>>>   ServerName sslhost3.example.com
>>>>   RewriteEngine on
>>>>   RewriteRule ^/(.*) https://sslhost3.example.com/$1 [L,R]
>>>> </VirtualHost>
>>>> <VirtualHost *:443>
>>>>   SSLEngine on
>>>>   ServerName sslhost3.example.com
>>>>   ProxyPass / http://localhost:8030/
>>>>   ProxyPassReverse / http://localhost:8030/
>>>>   SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:
>>>>     +MEDIUM:+LOW:+SSLv2:+EXP:+eNULL
>>>>   SSLCertificateFile /etc/ssl/example.com.crt
>>>>   SSLCertificateKeyFile /etc/ssl/private/example.com.key
>>>>   SetEnvIf User-Agent ".*MSIE.*" nokeepalive
>>>>      ssl-unclean-shutdown downgrade-1.0 force-response-1.0
>>>> </VirtualHost>
>>>>
>>>>
>>>> Now I want to add another SSL host.  I know that each SSL host needs to
>>>> have their unique IP and port pair.  This is due to the fact that SSL
>>>> encryption needs to happen before the hostname is disclosed to the
>>>> server.  That's why name based virtual hosting doesn't work.
>>>> However, with proxy I thought I could do the following:
>>>>
>>>> 1. Main Proxy Server
>>>>   Accepts connection on port 80 and 443.  Forwards proxies port 80 as
>>>> usual but forwards port 443 to second proxy server in clear text.
>>>>
>>>> 2. Second Proxy Server
>>>>   Now that the incoming traffic is not encrypted the name based
>>>> VirtualHost directive should work.
>>>>
>>>> So I invisioned the directives to be:
>>>>
>>>> <VirtualHost *:80>
>>>>   ServerName sslhost3.example.com
>>>>   RewriteEngine on
>>>>   RewriteRule ^/(.*) https://sslhost3.example.com/$1 [L,R]
>>>> </VirtualHost>
>>>> <VirtualHost *:80>
>>>>   ServerName sslhost4.example.com
>>>>   RewriteEngine on
>>>>   RewriteRule ^/(.*) https://sslhost4.example.com/$1 [L,R]
>>>> </VirtualHost>
>>>>
>>>> # Main Proxy Server
>>>> <Directory proxy:http://localhost:44344/>
>>>>   SSLRequireSSL
>>>>   Order deny,allow
>>>>   Allow from all
>>>> </Directory>
>>>> <VirtualHost *:443>
>>>>   SSLEngine on
>>>>   ServerName sslhost3.example.com
>>>>   ServerAlias sslhost4.example.com
>>>>   ProxyPass / http://localhost:44344/
>>>>   ProxyPassReverse / http://localhost:44344/
>>>>   SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:
>>>>     +MEDIUM:+LOW:+SSLv2:+EXP:+eNULL
>>>>   SSLCertificateFile /etc/ssl/example.com.crt
>>>>   SSLCertificateKeyFile /etc/ssl/private/example.com.key
>>>>   SetEnvIf User-Agent ".*MSIE.*" nokeepalive
>>>>      ssl-unclean-shutdown downgrade-1.0 force-response-1.0
>>>> </VirtualHost>
>>>>
>>>> # Second Proxy Server
>>>> <Directory proxy:http://localhost:8030/>
>>>>   Order deny,allow
>>>>   Allow from all
>>>> </Directory>
>>>> <VirtualHost *:44344>
>>>>   SSLEngine on
>>>>   ServerName sslhost3.example.com
>>>>   ProxyPass / http://localhost:8030/
>>>>   ProxyPassReverse / http://localhost:8030/
>>>>   SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:
>>>>     +MEDIUM:+LOW:+SSLv2:+EXP:+eNULL
>>>>   SSLCertificateFile /etc/ssl/example.com.crt
>>>>   SSLCertificateKeyFile /etc/ssl/private/example.com.key
>>>>   SetEnvIf User-Agent ".*MSIE.*" nokeepalive
>>>>      ssl-unclean-shutdown downgrade-1.0 force-response-1.0
>>>> </VirtualHost>
>>>>
>>>> <Directory proxy:http://localhost:8040/>
>>>>   Order deny,allow
>>>>   Allow from all
>>>> </Directory>
>>>> <VirtualHost *:44344>
>>>>   SSLEngine on
>>>>   ServerName sslhost4.example.com
>>>>   ProxyPass / http://localhost:8040/
>>>>   ProxyPassReverse / http://localhost:8040/
>>>>   SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:
>>>>     +MEDIUM:+LOW:+SSLv2:+EXP:+eNULL
>>>>   SSLCertificateFile /etc/ssl/example.com.crt
>>>>   SSLCertificateKeyFile /etc/ssl/private/example.com.key
>>>>   SetEnvIf User-Agent ".*MSIE.*" nokeepalive
>>>>      ssl-unclean-shutdown downgrade-1.0 force-response-1.0
>>>> </VirtualHost>
>>>>
>>>> So far I haven't gotten this to work.  Whatever I do it seems to pick
>>>> the first VirtualHost listed, seemingly ignoring the ServerName.  At the
>>>> point of processing the port 44344 request no encryption should hinder
>>>> the name based VirtualHost resolution, right?  Is there anything I'm
>>>> overlooking?
>>>>
>>>>   Claus
>>>>
>>>> PS:  I'm aware about mismatch between the SSL certificate and the domain
>>>> names.  At this point I'm not concerned about it.
>>>> _______________________________________________
>>>> Cialug mailing list
>>>> Cialug at cialug.org
>>>> http://cialug.org/mailman/listinfo/cialug
> 
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