[keycloak-user] problem with nginx reverse proxy and ip access control

[Jernej Porenta]

Hey Derek,

I had the exact same issue and tried multiple options:
- inverted undertow ip-access-control rule
- turning the nobs by proxy-address-forwarding mangling (changing headers etc.)
- checking out the client IP by request logging (which were right in the keycloak logs)
- multiple ways of specifying the rules within undertow (based on RH documentation)

None of them worked.

In the end, i implemented that at nginx level. It isn’t the most beautiful solution (k8s nginx ingress), but it is working as expected.

The only one, which I hadn’t tried at that time, is that maybe X-Forwarded-For header included multiple IPs (X-Forwarded-For: 1.2.3.4 5.6.7.8). You can test that by stripping them and add only original one with nginx.

br, Jernej

> On 19 Sep 2018, at 12:18, Derek Gibson <derek.gibson at cimenviro.com> wrote:
> 
> Hi there,
> 
> I'm having a hard time trying to get ip restriction working behind an nginx reverse proxy on Keycloak 4.3
> 
> 
> I have configured an ip filter as per https://www.keycloak.org/docs/4.3/server_admin/#ip-restriction <https://www.keycloak.org/docs/4.3/server_admin/#ip-restriction>
> 
> <subsystem xmlns="urn:jboss:domain:undertow:4.0">
>    <buffer-cache name="default"/>
>    <server name="default-server">
>        <ajp-listener name="ajp" socket-binding="ajp"/>
>        <http-listener name="default" socket-binding="http" redirect-socket="https" proxy-address-forwarding="true" enable-http2="true"/>
>        <https-listener name="https" socket-binding="https" security-realm="ApplicationRealm" proxy-address-forwarding="true" enable-http2="true"/>
>        <host name="default-host" alias="localhost">
>            <location name="/" handler="welcome-content"/>
>            <http-invoker security-realm="ApplicationRealm"/>
>            <filter-ref name="ipAccess"/>
>        </host>
>    </server>
>    <filters>
>        <expression-filter name="ipAccess" expression="path-prefix('/auth/admin') -> ip-access-control(acl={'10.10.10.10 allow'})"/>
>    </filters>
>    <servlet-container name="default">
>        <jsp-config/>
>        <websockets/>
>    </servlet-container>
>    <handlers>
>        <file name="welcome-content" path="${jboss.home.dir}/welcome-content"/>
>    </handlers>
> </subsystem>
> 
> and my nginx server block
> 
> server {
>    listen        443 ssl;
>    server_name    keycloak.example.com <http://keycloak.example.com/>;
>    location / {
>        proxy_set_header Host               $host;
>        proxy_set_header X-Real-IP          $remote_addr;
>        proxy_set_header X-Forwarded-For    $proxy_add_x_forwarded_for;
>        proxy_set_header X-Forwarded-Proto  $scheme;
>        proxy_pass https://keycloak-prx.example.com <https://keycloak-prx.example.com/>;
>    }
> }
> 
> This works as intended when I request it directly, however when I try to access via nginx reverse proxy I get a 403 regardless of the ip I set in the ip-access-control filter, whether I have the host ip, or the proxy or gateway.
> 
> Undertow debug shows that the correct ip's (as far as I understand that it should be) are being passed by nginx
> 
> 10:03:29,564 DEBUG [io.undertow.request] (default I/O-2) Matched prefix path /auth for path /auth/
> 10:03:29,565 DEBUG [io.undertow.request.security] (default task-3) Authentication result was ATTEMPTED for HttpServerExchange{ GET /auth/ request {X-Real-IP=[10.10.10.20], accept=[text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8], X-Amzn-Trace-Id=[Root=1-5b9b8771-70fa72df4ef4bf816434fcc5], accept-language=[en-US,en;q=0.9], accept-encoding=[gzip, deflate, br], user-agent=[Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36], Connection=[close], X-Forwarded-Proto=[https], X-Forwarded-Port=[443], X-Forwarded-For=[10.10.10.10, 10.10.10.20], cookie=[_ga=GA1.2.1510178336.1525250562; ajs_user_id=%22ca89cde3-6cac-4197-a5ad-aa966295c66d%22; ajs_anonymous_id=%2228cb540a-cb21-4200-a531-64b11ef909d8%22; ajs_group_id=%22customer%3A1%22], upgrade-insecure-requests=[1], Host=[keycloak.example.com <http://keycloak.example.com/>]} response {}}
> 
> but I do not get any debug logs for matches for /auth/admin, I only get an entry
> 
> 09:42:47,387 DEBUG [io.undertow.request] (default I/O-2) Matched prefix path /auth/admin for path /auth/admin/
> 
> and no subsequent security logs for that request 
> 
> Have I misconfigured something or could this be a bug?
> Is there any steps that I can take to debug this further?
> 
> my debug settings are 
> <subsystem xmlns="urn:jboss:domain:logging:3.0">
>    <console-handler name="CONSOLE">
>        <level name="DEBUG"/>
>        <formatter>
>            <named-formatter name="COLOR-PATTERN"/>
>        </formatter>
>    </console-handler>
>    ...
>    <logger category="io.undertow">
>        <level name="DEBUG"/>
>    </logger>
>    ...
> </subsystem>
> all else is INFO
> 
> Would really appreciate any help at all on this
> thanks
> Derek
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