Issue AEM-6.1 Sling POST Servlet- Upload an image to AEM DAM

kautuksahni wrote...

Hi 

As mentioned by Opkar Gill, if the error is CSRF, then configure the referrer filter.

Issues with Cross-Site Request Forgery

This is a security issue from the CRX Security Checklist, that is also appropriate to CQ.

To address known security issues with Cross-Site Request Forgery (CSRF) in CRX WebDAV and Apache Sling you need to configure the Referrer filter.

The referrer filter service is an OSGi service that allows you to configure:

• which http methods should be filtered
• whether an empty referrer header is allowed
• and a white list of servers to be allowed in addition to the server host.

By default, all variations of localhost and the current host names the server is bound to are in the white list.

To configure the referrer filter service:

• Open the Apache Felix console (Configurations) at:
   http://<server>:<port_number>/system/console/configMgr

• Login as admin.

• In the Configurations menu, select:

      Apache Sling Referrer Filter
 

• In the Allow Hosts field, enter all hosts that are allowed as a referrer. Each entry needs to be of the form
   <protocol>://<server>:<port> 
For example:

  • http://allowed.server:80 allows all requests from this server with the given port.
  • If you also want to allow https requests, you have to enter a second line.
  • If you allow all ports from that server you can use 0 as the port number.
 

• Check the Allow Empty field, if you want to allow empty/missing referrer headers.

• Edit the methods this filter should use for checks with the Filter Methods field.
 

• Click Save to save your changes.

Link: https://docs.adobe.com/docs/en/aem/6-1/administer/security/security-checklist.html#Protect against Cross-Site Request Forgery

 

I hope this would help you.

Thanks and Regards

Kautuk Sahni

 

 

 

Hello Kautak,

This suggestion was implemented but did not help. An Adobe consultant recommended we make this a component and that is how this issue got resolved.

I may already be late in responding.

We were facing the same issue with that nagging CSRF error. We included a dependency(granite.csrf.standalone) to our component's client lib.to solve the issue

It's documented here 

For anyone facing similar issues, please find the workaround, if you do not want to write a servlet but would like to use the OOTB post servlet

Just  dump in the html into a component, an html component is what i have used. Do remember to upload multiple assets at a path, just like the aem dam, you could have the form action similar to "/content/dam.createasset.html"

Hey, Did you try writing your own POST Servlet instead of using the SlingPostServlet ?

kautuksahni wrote...

Hi 

As mentioned by Opkar Gill, if the error is CSRF, then configure the referrer filter.

Issues with Cross-Site Request Forgery

This is a security issue from the CRX Security Checklist, that is also appropriate to CQ.

To address known security issues with Cross-Site Request Forgery (CSRF) in CRX WebDAV and Apache Sling you need to configure the Referrer filter.

The referrer filter service is an OSGi service that allows you to configure:

• which http methods should be filtered
• whether an empty referrer header is allowed
• and a white list of servers to be allowed in addition to the server host.

By default, all variations of localhost and the current host names the server is bound to are in the white list.

To configure the referrer filter service:

• Open the Apache Felix console (Configurations) at:
   http://<server>:<port_number>/system/console/configMgr

• Login as admin.

• In the Configurations menu, select:

      Apache Sling Referrer Filter
 

• In the Allow Hosts field, enter all hosts that are allowed as a referrer. Each entry needs to be of the form
   <protocol>://<server>:<port> 
For example:

  • http://allowed.server:80 allows all requests from this server with the given port.
  • If you also want to allow https requests, you have to enter a second line.
  • If you allow all ports from that server you can use 0 as the port number.
 

• Check the Allow Empty field, if you want to allow empty/missing referrer headers.

• Edit the methods this filter should use for checks with the Filter Methods field.
 

• Click Save to save your changes.

Link: https://docs.adobe.com/docs/en/aem/6-1/administer/security/security-checklist.html#Protect against Cross-Site Request Forgery

 

I hope this would help you.

Thanks and Regards

Kautuk Sahni

 

 

 

I gave it a shot, but looks like it did not help, can you please try it from your end as well? I still see the "com.adobe.granite.csrf.impl.CSRFFilter isValidRequest: empty CSRF token - rejecting" which is not an error , but an INFO log level.

On the page , on submit, i see the error attached

Here is the link to the blog

http://blogs.adobe.com/experiencedelivers/experience-management/how_to_upload_animageviaslingpostservlet/

smacdonald2008 wrote...

See this blog that talks about uploading DAM assets using a custom sling servlet and Asset manager API

http://scottsdigitalcommunity.blogspot.ca/2013/07/uploading-files-to-adobe-experience.html

The benefit of a custom servlet is you have more control what happens when the image is posted to the server. 

 

Hey Scott,

I totally agree. but this was the approach chosen over the servlet for the time-being, for a simple form post with conditions using apache sling POST. But since this was working in 5.6.1, unsure what configuration might be missing to make this actually work.

Hi,

can you post the error? Is it a CSRF exception?

"com.adobe.granite.csrf.impl.CSRFFilter isValidRequest: empty CSRF token - rejecting"

Regards,

Opkar