Re: Heap use after free in parser.c

Jay Civelli via xml <[email protected]>
Newsgroups gmane.comp.gnome.lib.xml.general
Message-ID <CAJ6=x6=z-ekrAGJrXPJB2Av-bipxbcTP238mo-8j7o=spZdsuA@mail.gmail.com>
On Mon, Jan 22, 2018 at 7:53 AM, Nick Wellnhofer <[email protected]>
wrote:

> On 08/01/2018 22:43, Jay Civelli wrote:
>
>> On Mon, Jan 8, 2018 at 11:27 AM, Nick Wellnhofer <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>>     On 02/01/2018 20:08, Jay Civelli via xml wrote:
>>
>>         We ran into a heap use after free in Chromium
>> http://crbug.com/793715
>>         <http://crbug.com/793715> that I think I tracked down.
>>
>>     I don't have access to this page.
>>
>> You should have access now.
>>
>
> I still don't have access to the original Clusterfuzz report. I only found
> your reduced test case "bad_xml" but I couldn't reproduce the issue with
> xmllint. Given the stack trace and Chromium sources, it seems that you're
> using xmlReaderForMemory in recovery mode:
>
>
> https://chromium.googlesource.com/chromium/src/+/master/thir
> d_party/libxml/chromium/libxml_utils.cc
>
> Note that it's discouraged to use XML_PARSE_RECOVER in production code.
> This flag hides errors in invalid XML and exercises some less-tested code
> paths in libxml2.
>
Thanks, I'll look into removing it.

>
> For future reports, it would be helpful to provide test cases that show
> the problem with xmllint. The following flags should make xmllint behave
> similar to the Chromium code in question:
>
>     xmllint --stream --memory --recover file.xml

Got it, will do in the future.

>
>
> Good idea, done in new attached patch. Note that I changed the error from
>> the existing from XML_ERR_INVALID_ENCODING to XML_ERR_INVALID_CHAR which
>> seemed to make more sense.
>>
>
> I committed a minimal fix that only adds a call to xmlHaltParser.
>
Great, thanks. I tested locally, it does address the issue.

>
>
> https://git.gnome.org/browse/libxml2/commit/?id=ab362ab0ad3a
> f54406ae8237a525405c6e2a705b
>
> Nick
>

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