Hello, maybe you can try to set an environment variable which skips interpreting the content-length: https://tomcat.apache.org/connectors-doc/reference/apache.html#Advanced%20Environment%20Variables --> JK_IGNORE_CL
To get more information, you can also set the logfile and log-level to debug: JkLogLevel (same reference page as above). Greetings, Thomas -----Ursprüngliche Nachricht----- Von: Stefan Mayr <ste...@mayr-stefan.de> Gesendet: Samstag, 12. Februar 2022 14:24 An: Tomcat Users List <users@tomcat.apache.org> Betreff: mod_jk interference with ErrorDocument/Alias on HEAD request Hello Tomcat users, this week we were debugging a strange connection issue which I tracked down to an interference between Apache httpd and mod_jk. For the full picture, the infrastructure setup contains 1. a Loadbalancer providing HTTPS, HTTP/1.1 and HTTP/2 for Clients. 2. an Apache httpd 2.4 webserver (HTTP only) with mod_jk 3. a Tomcat mit AJP-Connector We have an application doing many different HEAD requests against an application running in the Tomcat server. The requests contain an Authorization header for Basic authentication. Expected response is a HTTP 200 OK or HTTP 401 if this particular user is not allowed to access that ressource. Because this is a HEAD request there must not be a response body according to RFC 2616. If there is a response body in the response to the HEAD request our loadbalancer does strange things: aborts the connection if the clients uses HTTP/2, SSL errors if using HTTP/1.1. But this is an issue on its own which we might have to solve with the vendor. Now comes the point where I need your help. We have a httpd configuration with mod_jk which generates these invalid response bodies on HEAD requests. I have a gut feeling this could be a bug with mod_jk. For demonstration purpose i created a minimal demo app which only is a WEB-INF/web.xml <?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="https://jakarta.ee/xml/ns/jakartaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_5_0.xsd" version="5.0"> <security-constraint> <web-resource-collection> <web-resource-name>Login</web-resource-name> <url-pattern>/*</url-pattern> </web-resource-collection> <auth-constraint> <role-name>manager</role-name> </auth-constraint> </security-constraint> <security-role> <role-name>manager</role-name> </security-role> <login-config> <auth-method>BASIC</auth-method> </login-config> </web-app> Then I place a JkMount in my Apache httpd configuration (+ minimal worker.properties): JkMount /demo/* ajp13_worker Testing this with curl works like expected: root@1ae8973f1b6b:~# curl -I -v localhost/demo/ * Trying 127.0.0.1:80... * TCP_NODELAY set * Connected to localhost (127.0.0.1) port 80 (#0) > HEAD /demo/ HTTP/1.1 > Host: localhost > User-Agent: curl/7.68.0 > Accept: */* > * Mark bundle as not supporting multiuse < HTTP/1.1 401 401 HTTP/1.1 401 401 < Date: Sat, 12 Feb 2022 12:57:33 GMT Date: Sat, 12 Feb 2022 12:57:33 GMT < Server: Apache/2.4.41 (Ubuntu) Server: Apache/2.4.41 (Ubuntu) < Cache-Control: private Cache-Control: private < WWW-Authenticate: Basic realm="Authentication required" WWW-Authenticate: Basic realm="Authentication required" < Content-Language: en Content-Language: en < Content-Type: text/html;charset=utf-8 Content-Type: text/html;charset=utf-8 < * Connection #0 to host localhost left intact But our default setup always includes custom error pages: Alias /error/ "/usr/share/apache2/error/" ErrorDocument 401 /error/HTTP_UNAUTHORIZED.html.var If both of those lines are added this results in a response body for the HEAD request. root@1ae8973f1b6b:~# curl -I -v localhost/demo/ * Trying 127.0.0.1:80... * TCP_NODELAY set * Connected to localhost (127.0.0.1) port 80 (#0) > HEAD /demo/ HTTP/1.1 > Host: localhost > User-Agent: curl/7.68.0 > Accept: */* > * Mark bundle as not supporting multiuse < HTTP/1.1 401 401 HTTP/1.1 401 401 < Date: Sat, 12 Feb 2022 12:56:27 GMT Date: Sat, 12 Feb 2022 12:56:27 GMT < Server: Apache/2.4.41 (Ubuntu) Server: Apache/2.4.41 (Ubuntu) < Cache-Control: private Cache-Control: private < WWW-Authenticate: Basic realm="Authentication required" WWW-Authenticate: Basic realm="Authentication required" < Content-Language: en Content-Language: en < Content-Type: text/html;charset=utf-8 Content-Type: text/html;charset=utf-8 < * Excess found: excess = 589 url = /demo/ (zero-length body) * Connection #0 to host localhost left intact Checking with tcpdump on port 8009 we see the expected response without a body from the Tomcat AJP connector. The tcpdump von port 80 reveals httpd is adding the configured ErrorDocument as response body. If we comment out either the Alias or ErrorDocument directive the response is correct again. Doing similar tests with CGI/PHP applications always show the correct response without a response body. This only affects requests which use mod_jk. So far I could reproduce this on SLES12 SP5 and SLES15 SP3 running Apache httpd 2.4.51 and a self compile mod_jk 1.2.46 (same with the included mod_jk 1.2.43) at work. At home the same happens on a stock openSUSE Leap 15.3 with Apache httpd 2.4.51 and mod_jk 1.2.43 as well as on Ubuntu 20.04 with httpd 2.4.41 and mod_jk 1.2.46. I didn't try to compile the latest mod_jk version yet because I didn't spot a relevant point in the changelog. Can anyone confirm this behaviour or point me to a configuration directive i missed? Thank you, Stefan Mayr --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org