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On 2019-08-23T12:53:50+00:00 A-abfalterer wrote:

The new CSRF protection of the Balancer Manager breaks editing
functionality for browsers that lowercase hostnames in the Referer:
header; e.g. Chrome

The error is based on the usage of strcmp() in the safe_referer()
function

https://github.com/apache/httpd/blob/2.4.x/modules/proxy/mod_proxy_balancer.c#L1107

Reply at:
https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1842701/comments/0

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On 2019-08-23T13:07:33+00:00 Covener-0 wrote:

(In reply to Armin Abfalterer from comment #0)
> The new CSRF protection of the Balancer Manager breaks editing functionality
> for browsers that lowercase hostnames in the Referer: header; e.g. Chrome
> 
> The error is based on the usage of strcmp() in the safe_referer() function
> 
> https://github.com/apache/httpd/blob/2.4.x/modules/proxy/mod_proxy_balancer.
> c#L1107

thanks for the report and sorry for the inconvenience.  Trunk r1865749
and proposing for backport to 2.4.x.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1842701/comments/1

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On 2019-09-06T14:14:05+00:00 Horst Platz wrote:

hi all,

mybe i found a kind of same problem. in my configuration i used
the balancer manager behind a proxy

 -------------
|Bastian Host |
|Apache Proxy | -----------> LB Apache Balancer Manger
 -------------

and i struggle in the problem with an update from Ubuntu 18.04
which i described in the following bug report

https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1842701

on localhost with lynx i figure out error log entrys with every
submit and no update from the load data etc.

:~# tail -f /var/log/apache2/management_error.log
[Wed Sep 04 12:28:58.249737 2019] [proxy_balancer:error] [pid 14669:tid 
140254497400576] [client 127.0.0.1:42844] AH10187: ignoring params in 
balancer-manager cross-site access
[Wed Sep 04 12:29:09.585221 2019] [proxy_balancer:error] [pid 14669:tid 
140254623291136] [client 127.0.0.1:42848] AH10187: ignoring params in 
balancer-manager cross-site access


i can reproduce this within debian 10

:~# apt-get install apache2

:~# dpkg -l | grep apache2
ii  apache2          2.4.38-3+deb10u1
ii  apache2-bin      2.4.38-3+deb10u1
ii  apache2-data     2.4.38-3+deb10u1
ii  apache2-utils    2.4.38-3+deb10u1

i download the prior version from the module and compile that version

http://svn.apache.org/repos/asf/httpd/httpd/tags/2.4.40/modules/proxy/mod_proxy_balancer.c

:~# apxs2 -c -i mod_proxy_balancer.c

:~# systemctl restart apache2

:~# lynx 127.0.0.1:81/balancer-manager
:~# elinks 127.0.0.1:81/balancer-manager
Browser: http://192.168.56.211:81/balancer-manager

i can use the balancer manager as expected without any error log entry

i compiled also that version from 
https://svn.apache.org/viewvc?view=revision&revision=1865749
but with no luck.

regards horst

Reply at:
https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1842701/comments/6

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On 2019-09-06T14:40:30+00:00 Covener-0 wrote:

can you try something like this since you had a sandbox env:

Index: modules/proxy/mod_proxy_balancer.c
===================================================================
--- modules/proxy/mod_proxy_balancer.c  (revision 1866509)
+++ modules/proxy/mod_proxy_balancer.c  (working copy)
@@ -1185,7 +1185,7 @@
     /* Ignore parameters if this looks like XSRF */
     ref = apr_table_get(r->headers_in, "Referer");
     if (apr_table_elts(params)
-        && (!ref || !safe_referer(r, ref))) {
+        && (ref &&  !safe_referer(r, ref))) {
         ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(10187)
                       "ignoring params in balancer-manager cross-site access");
         apr_table_clear(params);

No referer should pass through IIUC.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1842701/comments/8

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On 2019-09-06T15:04:18+00:00 Jorton-9 wrote:

Well, Eric you suggested it, so maybe I got it wrong ;)

In all valid requests to the balancer-manager the previous URI should be
the balancer-manager page, and hence Referer should be set.  So ignoring
params if Referer is not present was definitely deliberate.

So OP are you're saying this fails with lynx and works with elinks?

Reply at:
https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1842701/comments/9

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On 2019-09-06T15:09:35+00:00 Jorton-9 wrote:

BTW I can't comment on that Ubuntu page without creating an account, so
please point them to this comment

The referenced change to mod_proxy/mod_proxy_balancer has NOTHING to do
with CVE-2019-10092.

CVE-2019-10092 is fixed by
https://svn.apache.org/viewvc?view=revision&revision=1864191

Reply at:
https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1842701/comments/10

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On 2019-09-07T11:04:56+00:00 Horst Platz wrote:

if i came from ousite with firefox and on the console with elinks the
first connect

:~# http://192.168.56.225:81/balancer-manager

:~# tail -f /var/log/apache2/management_error.log
[Sat Sep 07 12:37:39.907268 2019] [proxy_balancer:error] [pid 6582:tid 
140508132738816] [client 192.168.56.1:52006] AH10187: ignoring params in 
balancer-manager cross-site access

:~# elinks 127.0.0.1:81/balancer-manager

:~# tail -f /var/log/apache2/management_error.log
[Sat Sep 07 12:40:42.786775 2019] [proxy_balancer:error] [pid 6582:tid 
140507992790784] [client 127.0.0.1:48454] AH10187: ignoring params in 
balancer-manager cross-site access

creates on error log entry but it workes with lynx first connect and
every submit creates the log entry

:~# lynx 127.0.0.1:81/balancer-manager

:~# tail -f /var/log/apache2/management_error.log
[Sat Sep 07 12:41:43.620865 2019] [proxy_balancer:error] [pid 6582:tid 
140507900471040] [client 127.0.0.1:48460] AH10187: ignoring params in 
balancer-manager cross-site access

[Sat Sep 07 12:42:20.582399 2019] [proxy_balancer:error] [pid 6582:tid 
140508132738816] [client 127.0.0.1:48466] AH10187: ignoring params in 
balancer-manager cross-site access
[Sat Sep 07 12:42:33.611602 2019] [proxy_balancer:error] [pid 6582:tid 
140508043147008] [client 127.0.0.1:48468] AH10187: ignoring params in 
balancer-manager cross-site access
[Sat Sep 07 12:42:37.749409 2019] [proxy_balancer:error] [pid 6582:tid 
140508026361600] [client 127.0.0.1:48470] AH10187: ignoring params in 
balancer-manager cross-site access

so yes lynx ist not working

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

with your patch on

http://svn.apache.org/repos/asf/httpd/httpd/tags/2.4.41/modules/proxy/mod_proxy_balancer.c

i got no errog log entrys and lynx is also working for my sandbox env.

thx horst

i create the hint on the ubuntu page

Reply at:
https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1842701/comments/11

------------------------------------------------------------------------
On 2019-09-09T08:08:47+00:00 Jorton-9 wrote:

Sorry I'm struggling to parse your comemnts, Horst.

>From a quick search it looks some versions of Lynx don't produce Referer
headers.  They won't work with mod_proxy_balancer since 2.4.41, because
we made tightened up the XSRF protection.  This is unfortunate but we
don't have a better way to protect against XSRF.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1842701/comments/14


** Changed in: apache2
       Status: Unknown => Confirmed

** Changed in: apache2
   Importance: Unknown => Medium

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  Apache2 Balancer Manager mod_proxy_balancer not working after Update

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