Re: [xml] [PATCH] Memory leak in xmlXPathEvalExpression()

[Daniel Veillard <veillard redhat com>]

On Sun, Oct 11, 2009 at 04:30:12PM +0100, Martin (gzlist) wrote:
> A patch and some tests for this issue are attached.
>
> On 10/10/2009, Ralf Junker <ralfjunker gmx de> wrote:
> > The following psydo-code (is actually Pascal code; I do not have a C memory
> > checker available) produces a 5-12 byte memory leak (unable to tell the
> > exact number of bytes):
>
> Okay, I got a few of these a while back but missed this one.
>
> >   XPathObj := xmlXPathEvalExpression('//a[ href=http://hello.com]',
> > XPathCtx);
>
> This is the only line in your example that matters, it's comes from
> trying to parse certain kinds of invalid xpath expressions. In case
> it's not clear, the URL needs string quoting in order for the
> expression to work as intended.
>
> The basic problem is that xmlXPathCompStep and other functions used
> for parsing location paths don't return a success indicator, and not
> every call checks to see if there was an error afterwards, so the
> parser tries to plow on for a bit before realising there was a
> problem.

  Yeah, it was a long time ago :)

Thanks for the patch applied, I just had to fix the expected error mesages
set in the python test

> Really the xpath parsing could do with some fuzz testing to see if
> there are any more of these lurking around.

  Well yes that would be a good idea,

Daniel

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