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On 5/15/20 08:42, ohaya wrote:
> Yes, I am using Oracle Access Manager (OAM) so we have what they
> call an "OAM webgate" that is integrated with the Apache. That
> webgate automatically populates an HTTP header named "remote_user"
> with the user that OAM authenticated.
> So the problem I having is trying to figure out how to "integrate"
> that with Tomcat.


> So we have:
> Browser <==> Apache+webgate <==> Tomcat (webapp)


First thing's first: Do you get your pages from Tomcat, but you aren't
authenticated, or do you get some other kind of error? Sounds like you
see your application, just no authentication.

If this is your first time doing this, I assume you mean you're trying
to figure out how to get it done, not trying to move a working
configuration from another environment./version to Tomcat 9, right?

There is nothing in the configuration you have posted so far that
leads me to believe you'll be sending any REMOTE_USER HTTP header to
Tomcat. Apache httpd doesn't (usually) auto-forward anything to
Tomcat. Your OAS module is more likely setting an environment variable
(remote_user) than an HTTP header. But it might be setting a header.
That would be good information to know.

To send arbitrary headers (etc.) to Tomcat via mod_proxy_ajp, you need
to configuration to do that. Let's take a look at the Tomcat
documentation to see how tomcatAuthentication="false" works.

Awesome, the documentation says nothing about how to tie-into it.
Well, the code says that tomcatAuthentication="false" means that AJP
can accept the REMOTE_USER /request attribute/ which is a special
servlet-thing which isn't the same as a header. So you have to arrange
for mod_proxy_ajp to send your "remote_user" (header or environment
variable) to Tomcat as a request attribute.

Here's how to do that. According to the mod_proxy_ajp docs:

Environment Variables

Environment variables whose names have the prefix AJP_ are forwarded
to the origin server as AJP request attributes (with the AJP_ prefix
removed from the name of the key).

Cool, so we just need to set an environment variable AJP_REMOTE_USER
and it will be sent as an attribute. So I think we have all the
pieces, now. So try this:

  # Copy OAS's REMOTE_USER env variable -> AJP_REMOTE_USER for Tomcat

Just before your ProxyPass and friends.

I'm not entirely sure that will work. SetEnv doesn't say what "value"
can be; I'm hoping it will see that token and understand it's an
environment variable.

If that works, you're all set. Another option would be to tell OAS
that the environment variable you want is actually AJP_REMOTE_USER,
but if you want to use the environment variable "remote_user" for
other things, maybe making a copy like this is a better idea.

If that doesn't work, it may be that OAS is really setting an HTTP
header, which would be weird but, hey, Oracle is weird.

If you have to deal with HTTP headers, you'll want to do this:

  # Disallow any random client from masquerading as any user
  RequestHeader unset REMOTE_USER early
  # Copy OAS's REMOTE_USER header -> AJP_REMOTE_USER for Tomcat

Note the lack of a trailing "e" on the value of the environment variable

Hope that helps,
- -chris

PS It looks like there's some room to improve Tomcat's documentation
of the "tomcatAuthentication" configuration attribute.

> On Friday, May 15, 2020, 08:36:18 AM EDT, André Warnier
> (tomcat/perl) <a...@ice-sa.com> wrote:
> Let me give my 5 cent.
> In the tomcat AJP Connector Tomcat, you use the
> tomcatAuthentication attribute :
> <Connector port="8009" protocol="AJP/1.3" redirectPort="8443"
> tomcatAuthentication="false"/>
> This setting has the effect that tomcat will "believe" the
> authenticated user-id that Apache is passing to it in the AJP
> protocol messages that Apache sends to tomcat, and not try to
> re-authenticate again at the tomcat level. (Note : this is not
> done by a "REMOTE_USER" HTTP header added by Apache; it happens via
> some internal variable specific to the AJP protocol).
> Of course, for this, the request needs to be first authenticated
> in Apache (so that it has a user-id to pass to tomcat).
> So do you have anything at the Apache httpd side, which
> authenticates the user before the request gets passed to tomcat
> (via AJP) ?
> On 15.05.2020 14:08, ohaya wrote:
>> Hi Olaf,
>> Thanks. I do appreciate that! I will do more digging.
>> Jim
>> On Friday, May 15, 2020, 07:41:50 AM EDT, Olaf Kock
>> <tom...@olafkock.de> wrote:
>> On 15.05.20 13:23, ohaya wrote:
>>> Hi,
>>> I just tried adding the secret to the Apache side:
>>> ProxyPass ajp://192.168.218.XXX:8009 secret="123"
>>> ProxyPassReverse ajp://192.168.218.XXX:8009 secret="123"
>>> and I get an error when I try to start Apache:
>>> AH00526: Syntax error on line 554 of
>>> /apps/oracle/apache/conf/httpd.conf: ProxyPass unknown Worker
>>> parameter
>>> I am currently using Apache 2.4.39. Is there another way to
>>> specify the "secret"?
>> With 9.0.20 you do not yet need to pass a secret - that came
>> along later (somewhere around 30-33 AFAIR). However, you'll need
>> to make sure that your AJP port is only available for the reverse
>> proxy and nobody else - there was a recent security disclosure,
>> which led to the change of many default settings for the AJP
>> connector in the current releases.
>> It boils down to the last sentence of my previous answer: I've
>> never used REMOTE_USER headers for authentication, and there's
>> no indicator in your setup that you're allowing Tomcat to trust
>> such a header. I might be completely off here, but as nobody else
>> answered yet, I thought I'd give it a try.
>> Olaf
>>> Thanks, Jim
>>> On Friday, May 15, 2020, 07:04:44 AM EDT, ohaya
>>> <oh...@yahoo.com.invalid> wrote:
>>> Hi,
>>> The Tomcat version I am using is 9.0.20. I will take a look at
>>> the changelog.
>>> This is the first time I have tried this, and I couldn't find
>>> much info, so I appreciate the feedback. I will look for info
>>> about "secret".
>>> I wasn't sure about the format on the Apache side for the
>>> ProxyPass/ProxyPassReverse - does what I posted look all
>>> right?
>>> Also, when I was searching around for info, I saw some
>>> comments that seem to be saying that the "tomcatAuthentication"
>>> parameter on the Tomcat connection was no longer supported or
>>> something like that?
>>> Also re. "secret" on the Tomcat side: If that is set to, for
>>> example, "mysecret", how do I pass that on the Apache side?
>>> Thanks again, Jim
>>> On Friday, May 15, 2020, 03:33:19 AM EDT, Olaf Kock
>>> <tom...@olafkock.de> wrote:
>>> On 15.05.20 09:06, oh...@yahoo.com.INVALID wrote:
>>>> Hi,
>>>> I am using an Apache proxy in front of Tomcat 9, and I am
>>>> using AJP connection to connect from the Apache to Tomcat,
>>>> and I have the Apache sending a username to the Tomcat in a
>>>> REMOTE_USER header.
>>>> In the Tomcat server.xml I have:
>>>> <Connector port="8009" protocol="AJP/1.3"
>>>> redirectPort="8443" tomcatAuthentication="false"/>
>>>> In the Apache httpd.conf, to test, this I have:
>>>> <LocationMatch /myapp*> ProxyPass ajp://192.168.218.XX:8009
>>>> ProxyPassReverse ajp://192.168.XX.224:8009 </LocationMatch>
>>>> But when I access the app via the Apache, it is not
>>>> automatically logging me into the app.
>>>> Is there anything else that I have to do to get this to work
>>>> besides what I did above?  Is there something that I have to
>>>> modify in the app itself to get this to work?
>>> Hi Jim,
>>> which exact version of Tomcat 9 are you using? Note that there
>>> were significant changes for the default and required
>>> configuration for the AJP connector, in order to use it. Best
>>> to find all of them: Search for AJP in the change log
>>> tomcat.apache.org/tomcat-9.0-doc/changelog.html
>>> Notable among them: Everything to do with "secret", and the
>>> default bind address, "localhost", for the AJP connector. i.e.
>>> I'd expect this configuration to be insufficient for any of
>>> the latest releases.
>>> I haven't ever used this REMOTE_USER authentication, but
>>> nothing in the configuration that you've posted gives any clue
>>> about what you do and what you send. I would expect Tomcat to
>>> *not* blindly accept any REMOTE_USER header by default, unless
>>> it's whitelisted and explicitly asked for - it otherwise would
>>> be a great way to exploit servers that don't have a remote
>>> proxy (or one where the remote proxy is configured to remove
>>> this header). Nothing in the configuration you post gives me a
>>> hint about what you do to make tomcat accept and trust this
>>> header.
>>> Olaf
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