External XML entities are not loaded with modern libxml2

• Component: XML
• Status: RESOLVED FIXED

[Alexey Proskuryakov]

With ToT libxml2, I'm seeing http/tests/security/xss-DENIED-xml-external-entity.xhtml fail because it doesn't even attempt to load the file, and thus doesn't generate a failure message.

<rdar://problem/13047266>

[Alexey Proskuryakov]

The change in behavior was <https://git.gnome.org/browse/libxml2/commit/?id=4629ee02>.

[Alexey Proskuryakov]

Created attachment 197394 [details]
proposed fix

There are many differences between createStringParser and createMemoryParser. I'm only fixing one, because I don't know if any of the other differences are intentional.

Notably, I'm not adding XML_PARSE_NODICT - I checked the history, and I couldn't find the reason why createMemoryParser uses it.

[Darin Adler]

Comment on attachment 197394 [details]
proposed fix

View in context: https://bugs.webkit.org/attachment.cgi?id=197394&action=review

> Source/WebCore/xml/parser/XMLDocumentParserLibxml2.cpp:506
> +    xmlCtxtUseOptions(parser, XML_PARSE_NOENT);

It might be nice to have a comment explaining why this is the right option to use.

> Source/WebCore/xml/parser/XMLDocumentParserLibxml2.cpp:531
>      // Copy the sax handler

Wow, lame comment.

> Source/WebCore/xml/parser/XMLDocumentParserLibxml2.cpp:534
>      xmlCtxtUseOptions(parser, XML_PARSE_NODICT | XML_PARSE_NOENT);

It might still be nice to have a comment explaining why these are the right options to use.

[Alexey Proskuryakov]

Committed <http://trac.webkit.org/r148144>. I changed comments a little, but I don't understand this code enough to explain everything about it.

[Zan Dobersek]

*** Bug 104680 has been marked as a duplicate of this bug. ***