On 14.10.2018 02:29, Tony Esposito wrote:
Hello André,
It's routed through a server...
A co-worker noticed a Tomcat valve that might do the trick...
https://github.com/lokechenlin/tomcat-auto-login-valve
Your thoughts?
They are as follows :
If that works, fine.
But as per Occam's razor principle, one should not introduce more complexity than
necessary. One additional dependency risks adding additional burdens in terms of
debugging, support, maintenance etc.
And there shouldn't really be a need for anything additional.
Assuming that indeed the intermediate routing server adds this Basic Auth header, with a
certain user-id/password pair, and that this user/password is always the same.
(That's a big if of course).
And assuming that indeed something as yet unidentified in the webapp, introduces a need
for Basic Auth, and that you cannot find it or remove it.
Then the solution would be, to make sure that this Basic Auth succeeds.
(One reason being, that the lockout Valve - which apparently is also present - would not
lockout this user, if it's authentication succeeded.)
To make the Basic Auth succeed, one would have to insure that the Tomcat Realm that is
being used by this webapp to *verify* the correctness of this userid/password pair, indeed
knows this userid/password pair, and responds positively when enquired from.
Of course, this requires finding out first, which Realm is being used, to back-up this
Basic Auth. And that also would require finding out which component wants this Basic Auth.
But you can try at least one thing, just to check :
In the standard "vanilla" Tomcat as downloaded from the Tomcat website, there
is :
- in the file conf/server.xml, a tag like : <Resource name="UserDatabase"
auth="Container"..
- this tag points to a file, normally : pathname="conf/tomcat-users.xml"
- that file "conf/tomcat-users.xml", there is a section, normally
commented-out, like :
<!--
<role rolename="tomcat"/>
<role rolename="role1"/>
<user username="tomcat" password="<must-be-changed>" roles="tomcat"/>
<user username="both" password="<must-be-changed>" roles="tomcat,role1"/>
<user username="role1" password="<must-be-changed>" roles="role1"/>
-->
What you could try is to copy the following tags to a non-commented-out section
like this :
<role rolename="tomcat"/>
<user username="(user-that-you know)" password="(password-that-you-know, in clear)"
roles="tomcat"/>
save the file, and restart tomcat.
Then see if it works.
Chances are, that whoever configured this app in the first place, took the path of least
resistance, and configured that webapp for Basic Auth, using the simplest configuration
available, which is the above using a simple file as the back-end for authentication.
By making the changes above, you may make your mystery user/password known to this simple
Realm, and so maybe now its authentication will succeed.
@others : if any of the Tomcat devs is reading this, I am curious about
something :
If a HTTP request, in an unsollicited way, contains a Basic Auth "Authorization:" header,
could this automatically trigger some Basic Auth code in Tomcat, even if the webapp being
targeted does not have any such security constraints ?
I would assume not, but just in case..
Tony
-----Original Message-----
From: André Warnier (tomcat) [mailto:a...@ice-sa.com]
Sent: Saturday, October 13, 2018 4:38 PM
To: users@tomcat.apache.org
Subject: Re: Tomcat 8 and authenticating Basic Auth users
On 13.10.2018 18:54, Tony Esposito wrote:
Hello André,
Thank you for taking the time to put together this excellent explanation.
I do not have control over the server that is passing me the Basic Auth header,
unfortunately.
Ok, so to make things clearer : when Tomcat receives a request for this "myapp"
application, where does this request come from ?
From a user browser, or from another server directly ?
You mentioned "In other words, there is no "trick" to add to stop Tomat trying
to authenticate the client. By default, it doesn't.
If it does, it is because it was asked to, by something added to the default
configuration."
Ok, maybe the server IS asking for Basic Auth. I inherited this
server (and this dilemma) show how/where do I check to see if Basic
Auth is 'on'? Because I don't see it and (less valid)
That's the puzzle indeed, if the "myapp" webapp's web.xml does not contain any
<security-> thing, and neither does the general conf/web.xml (which gets merged with
every webapp's web.xml, so it was a good idea to check there too).
I think that you will have to activate (and look at) the Access Log, to find
out which requests really come into your server.
Look here :
http://tomcat.apache.org/tomcat-8.5-doc/config/valve.html#Access_Log_Valve
The Access Log produces lines like this :
127.0.0.1 - - [10/Oct/2017:17:54:41 +0200] "GET /favicon.ico HTTP/1.1" 200
21630 The penultimate value is the status code returned by Tomcat to the client, for this
request. The last value is the (data) size of the response (excluding headers).
You will be looking for requests which trigger a status code 401.
If there are any, that is a clear sign that the corresponding application (with
the URL in the same line) has some auth. requirement.
I was told by the previous web admin that Basic Auth was turned off.
Disregard that. Basic Auth cannot be "turned off". It is an inherent part of
the code (of any webserver, because it is mandated by the HTTP RFC); it is always there.
But it "activates" only when it is told to activate.
Thank you again for your time
Tony
-----Original Message-----
From: André Warnier (tomcat) [mailto:a...@ice-sa.com]
Sent: Saturday, October 13, 2018 7:53 AM
To: users@tomcat.apache.org
Subject: Re: Tomcat 8 and authenticating Basic Auth users
On 13.10.2018 04:56, Tony Esposito wrote:
But you still want your application to see this Basic Auth header, because it needs to
check the "standard password" in it, right ?
(Otherwise, describe precisely what you want).
If there is a way to disable Basic Auth (i.e. not compel the user to
authenticate yet again) without triggering on the password or ignoring the
header altogether, then the password is not important.
I mentioned the password in the hopes that I could use it in some way to
trigger the disabling of Basic Auth.
P.S.
1) You say "Installed 'out of the box - as is'", but what box ?
The standard Tomcats 8.0 or 8.5 do not have an active Connector for port 8088.
So it does not look as if it is so 'out of the box - as is'.
Where does that Tomcat come from, really ?
It was installed by the previous admin -- I inherited it.
Of course, there are other web apps on other ports. For example, there are 2
Connectors defined in the server.xml file.
When I said 'as is' I was thinking in the context of Basic Auth. I have done
nothing to change Basic Auth.
2) your application has a WEB-INF/web.xml file in it.
What does it say about authentication ?
The <TOMCAT_INSTALLED_DIRECTORY>/webapps/WEB-INF/myapp/web.xml file for each
app has no security constraints.
The <TOMCAT_INSTALLED_DIRECTORY>/conf/web.xml file also has no security
constraints.
There is no web.xml file under
<TOMCAT_INSTALLED_DIRECTORY>/webapps/ROOT/WEB-INF.
Was there anything in particular you were referring to?
No. But that is strange.
Not that this would imply in any way that I encourage you to set up some form
of bastard authentication without really knowing what you're doing (obviously),
but here are some pointers :
A browser (or any respectful-of-the-HTTP-rfc client), will *send* an
"Authorization:
Basic" header (which contains a user-id and password in clear, just
Base64-encoded) to a server, *only* after the following has happened :
1) the client makes a first request to the server, for some URL
2) the server checks if the requested resource is "protected".
If not, it sends the resource to the client and that's then end of this
request.
3) If the resource is protected, the server checks if the client's request already contains some form of authorization.
If the "protection" indicates that this is protected by a "HTTP Basic authentication", then what
the server will be looking for, is a "Authorization:" header, with a type "Basic".
4) if the request already contains such a header, the server decodes it into a
user-id/password, and /then/ checks with whatever back-end is configured (can be a file,
or a database, or whatever - that's what Tomcat calls a "Realm"), to see if
these credentials are correct.
5) If the credentials are ok, the server returns the requested resource, and
that's the end of the request.
6) If the credentials are not ok, the server returns a response to the client, with a "status code" 401,
meaning "needs authentication". If the resource is protected by an authentication "Basic", then
the server response will include a "WWW-authenticate: Basic"
header.
7) when the client receives this response, if it is a browser, it will then popup a login
dialog, to request the user-id/password from the user. When the user has entered that
userid/pw, the client will re-send the same request to the server, but this time with a
"Authorization:" header containing the userid/passwrd entered by the user.
(If that client is not a browser, it is supposed to fetch a userid/pw from
somewhere, and do the same).
8) go back to (2)
That is how Basic Auth works, in the HTTP RFC and in Tomcat.
There is something special about Basic Auth, in the sense that once a
client has succesfully accessed a location on the server, it will keep
sending the same
Authorization: header for that same location, without prompting the user again,
until you close the program and start anew.
Now consider the above carefully, because it has some implications :
a) the server will not send a 401 rsponse to the client, if the
accessed resource is not protected by a Basic authentication
b) without a 401 received from the server, a normal client will not
send an "Authorization:" header
c) if the client nevertheless sends an Authorization header, for a
resource that is not protected on the server, the server will ignore
this header
So there is something wrong, either in your explanations so far, or in the configuration
of your server, or the client, because the server should not be "challenging"
the client (with a 401), unless the application which the client tries to access is
protected by a Basic authentication.
And the client should not be sending a Basic Authorization header, unless it
has been challenged previously by the server (with a 401).
Which comes back to something Christopher mentioned already a good while back,
but which you seem to keep ignoring : if you do not want the client to try to
authenticate, then do not protect your application.
In other words, there is no "trick" to add to stop Tomat trying to authenticate
the client. By default, it doesn't. If it does, it is because it was asked to, by
something added to the default configuration.
Now if you want the client to send a Basic Authorization, but you want Tomcat
to ignore it, then tough luck, because the two go together. You cannot eat your
cake and have it.
The only way you could achieve that, is by writing your own "Realm", which
always responds OK, no matter what the client-id/pw are.
But there you are in uncharted and unsupported territory, so beware.
Tony
-----Original Message-----
From: André Warnier (tomcat) [mailto:a...@ice-sa.com]
Sent: Friday, October 12, 2018 6:54 PM
To: users@tomcat.apache.org
Subject: Re: Tomcat 8 and authenticating Basic Auth users
On 13.10.2018 00:04, Tony Esposito wrote:
Addendum:
The user "myuser" attempts to authenticate once, fails, and on the second
attempt the WARNING is thrown (i.e. user locked) which is to be expected.
I want the user "myuser" not to authenticate at all by having the Tomcat
instance 'ignore/bypass' the Basic Auth (that is received in the header).
But you still want your application to see this Basic Auth header, because it needs to
check the "standard password" in it, right ?
(Otherwise, describe precisely what you want).
P.S.
1) You say "Installed 'out of the box - as is'", but what box ?
The standard Tomcats 8.0 or 8.5 do not have an active Connector for port 8088.
So it does not look as if it is so 'out of the box - as is'.
Where does that Tomcat come from, really ?
2) your application has a WEB-INF/web.xml file in it.
What does it say about authentication ?
Tony
-----Original Message-----
From: Tony Esposito
Sent: Friday, October 12, 2018 4:42 PM
To: Tomcat Users List <users@tomcat.apache.org>
Cc: Tony Esposito <tony.espos...@region10.org>
Subject: RE: Tomcat 8 and authenticating Basic Auth users
Hi Christopher,
The 'web server in question' is the Tomcat web server that I am trying
to get to ignore Basic Auth.
Installed 'out of the box - as is', this Tomcat web server instance
throws the error
WARNING [http-nio-8088-exec-25]
org.apache.catalina.realm.LockOutRealm.authenticate An attempt was made to authenticate
the locked user "myuser"
whenever a user (who has SSO'd successfully) tries to reach the web app
that runs on that Tomcat web server.
Tony
-----Original Message-----
From: Christopher Schultz [mailto:ch...@christopherschultz.net]
Sent: Friday, October 12, 2018 3:33 PM
To: users@tomcat.apache.org
Subject: Re: Tomcat 8 and authenticating Basic Auth users
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Tony,
On 10/12/18 16:24, Tony Esposito wrote:
Some very good feedback here. Thank you.
The web server in question doesn't need to authenticate any users
at all. But, as a part of the SSO handoff, the web server in
question is being passed Basic Auth in the header.
Any further authentication (e.g. the examination of the header) is
handled by the application. So, with regard to the web server in
question, how to ignore the Basic Auth?
What is "the web server in question"? Most web servers will ignore
authentication headers unless they have been specifically configured to do something with
it. You shouldn't have to do anything specific to get the web server to ignore those
headers.
- -chris
-----Original Message----- From: Christopher Schultz
[mailto:ch...@christopherschultz.net] Sent: Friday, October 12,
2018 3:07 PM To: users@tomcat.apache.org Subject: Re: Tomcat 8 and
authenticating Basic Auth users
Tony,
On 10/12/18 15:41, Tony Esposito wrote:
Concerning tomcat-user.xml versus database: The number of users
has increased by an order of 2 magnitudes AND we don't know ahead
of time who those users will be. The user count is an estimate of
the number of companies (known) multiplied by the number of users
at each company (unknown - we know it is greater than 1).
Uhh... you need to authenticate users but you don't know who they are?
This sounds like either you don't need authentication or you are
doing something very dangerous.
Perhaps you are trying to solve Y but you are asking about X. What
is Y? What is the use-case, here? What are you protecting? Why do
you need authentication? How are you expected to do it without
being able to identify users?
This seems like a good case for using CLIENT-CERT authentication
where you trust each company's root cert and each employee at that
company gets their cert issued by their company. There are problems
with CLIENT-CERT authentication (like revocation is a PITA) but at
least it fits the use-case better.
Another option would be to tie-into each company's LDAP server.
Then, they can use their own username+password just like they use
for other services.
Or, if you don't or can't implement the above, use something like
SAML/OAuth to transfer a user from one trusted system (like a
client company's system) into your own. You can request specific
user information be set to you as a part of that SSO handoff and
you can "register" them "locally" so you'll recognize them the next
time they authenticate.
Concerning Basic Auth:
Users are already signed on via SSO thru another application.
And they cannot login directly to this application. A header is
passed to my web app which has the static password (so I can't do
much about that). (Yes, bad...bad...). Unfortunately, the header
also has Basic Auth passed to my application.
You can always ignore that header.
I need Tomcat to pass this request on through, ignoring the Basic
Auth in the header.
No problem: just remove all authentication and authorization
configuration from web.xml and Tomcat will happily pass those
headers to your application without doing anything to them. Tomcat
will also happily pass that information to your application even if
those headers are being used for authentication and authorization.
-chris
-----Original Message----- From: Christopher Schultz
[mailto:ch...@christopherschultz.net] Sent: Friday, October 12,
2018 2:25 PM To: users@tomcat.apache.org Subject: Re: Tomcat 8 and
authenticating Basic Auth users
Tony,
On 10/12/18 14:45, Tony Esposito wrote:
Thank you André for this feedback.
If I may, I wish to approach this from another angle. (The user
community is larger than at first anticipated).
Since you are switching away from tomcat-users.xml to a real data
store, why does a larger user community change things further?
If the header received has a certain password (which is static
for all users requesting access), then bypass Basic Auth and let
the user connect.
(The application does more security checking and authentication
on the header.)
So the question becomes:
How to disable Basic Auth when the header contains a password
which is static for all users requesting access?
This make zero sense.
HTTP Basic authentication will require the user to enter their
credentials. Once they enter their credentials, you'll inspect the
password for some magic value and then you want to retroactively
DISABLE HTTP Basic auth? I believe that requires timey-wimeyness.
Why not simply always require username+password, and then
opportunistically perform additional checks (as mentioned, but not
described) above? Once the user has authenticated successfully,
the browser will continue to send the
username+password with each successive request and the user won't
be asked again for their credentials.
The definition of "authenticated successfully" from the browser's
view is when the server stops sending the "WWW-Authenticate"
response header.
BTW static password == bad bad bad bad bad bad bad bad bad
If you have a static password, why bother asking for it in the
first place? It's like requiring a username + password for a
terminal and then stamping the username and password on the
monitor. You may as well remove the challenge.
-chris
-----Original Message----- From: André Warnier (tomcat)
[mailto:a...@ice-sa.com] Sent: Friday, October 12, 2018 11:29 AM
To: users@tomcat.apache.org Subject: Re: Tomcat 8 and
authenticating Basic Auth users
Hi.
On 12.10.2018 16:38, Tony Esposito wrote:
Hello, Using Tomcat 8.0.22 on Linux CentOS 6.10:
Trying to setup Tomcat to authenticate users that use Basic Auth.
I could (possibly) enter these users into the tomcat-users.xml
file but we are dealing with 1000 potential users.
What happens instead is (of course) the users fail to
authenticate and then subsequent attempts by the same user locks
the user's account.
11-Oct-2018 16:21:37.970 WARNING [http-nio-8088-exec-25]
org.apache.catalina.realm.LockOutRealm.authenticate An attempt
was made to authenticate the locked user "myuser"
This is 'normal' since after a failed attempt to log in, Tomcat
suspects a 'brute force attack' and locks the account.
I don't want to lose that security but (as mentioned above) I
can't just enter all users into the tomcat-users.xml file
So the basic question: How to do authentication of 1000
users that use Basic Auth?
Thanks.
Tony
There are two separate parts to this (and it is not specific to
Tomcat) :
- the "basic auth" part, is the way it talks to the browser, to
get a userid/pw (in this case, through a browser popup dialog)
- the "realm", is the way that the server *verifies* the
user-id/pw, with some back-end "authority". In your case, you
have specified that this realm is a file. But it can be something
else, like a database.
The two are independent, and you can mix and match according to
your needs. The on-line Tomcat documentation helps, see :
http://tomcat.apache.org/tomcat-8.5-doc/realm-howto.html
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