2014-03-26 17:34 GMT+04:00 Robert Olofsson <[email protected]>:
> Hi!
>
> I just started an upgrade of our tomcat, 7.0.47, to 7.0.52 and got into a
> problem. Tomcat did not want to start our webapp. Looking in the log
> I see:
>
> Mar 26, 2014 2:10:42 PM org.apache.catalina.startup.ContextConfig
> parseWebXml
> SEVERE: Parse error in application web.xml file at
> jndi:/localhost/bios/WEB-INF/web.xml
> java.io.FileNotFoundException: Could not resolve XML resource [null] with
> public ID
>  [null], system ID [dpservices.xml] and base URI
> [jndi:/localhost/bios/WEB-INF/web.xml]
> to a known, local entity.
>
> Not very helpful!
>

It says "dpservices.xml" and "/bios/WEB-INF/web.xml".
That is enough for you to locate the problematic file.
It says what API is being called.

> Looking in our web.xml I find that it starts with:
> <?xml version="1.0"?>
> <!DOCTYPE web-app [ <!ENTITY service SYSTEM "dpservices.xml">]>
> ...
>
> Checking the directory and the dpservices.xml file is there.
>
> After a bit of git cloning, git grep:ing and similar I find that:
>
> "7.0.51:Change default value of |xmlBlockExternal| attribute of Context.
>  It is |true| now"
>
> There is no bug referenced so I am not sure why this change was made.
> Is there some security problem with external entities that I should know of?
> Is there a bug where I can read more? (I can not been able to find anything
> specific to this from google).

CVE-2013-4590

The option controls whether the XML parser is allowed to access
external files such as entities, schemas, DTDs etc.

People using such tricks as you are rare. A more often case is typos
in schema or DTD URLs. [1]  With this option being 'true' the parser
fails fast, without trying to contact the external sun/oracle sites.

[1] https://bugs.eclipse.org/bugs/show_bug.cgi?id=351040


> Setting xmlBlockExternal="false" in the context makes things start
> up as they should again and I can continue with testing the new
> version.
>
> It would be nicer if the parse error also said something like "...external
> entities are not allowed, check the xmlBlockExternal context property..."
>


Best regards,
Konstantin Kolinko

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