[CSS Shapes] Negative raster shape height leads to crash

• Component: CSS
• Status: RESOLVED FIXED

[Zoltan Horvath]

The original test was provided by the u-szeged fuzzer. I reduced the test case and handled the negative margin-IntRect case in the shapes code.

[Zoltan Horvath]

Created attachment 236839 [details]
backtrace

[Zoltan Horvath]

Created attachment 236842 [details]
Patch

[Bem Jones-Bey]

Comment on attachment 236842 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=236842&action=review

Given the complexity of the test case, I'm not convinced this is the proper fix.

> Source/WebCore/ChangeLog:9
> +        The original test was provided by the u-szeged fuzzer. I reduced the test
> +        case and handled the negative margin-IntRect case in the shapes code.

Can you give a better description of what this is fixing?

> LayoutTests/fast/shapes/shape-outside-floats/shape-outside-raster-shape-negative-height.html:3
> +* {

This test seems way too complex, especially since you're matching everything here. Are you sure you couldn't get something simpler? If you can't reduce it to simply a single float with shape-outside and a negative height margin box, I wonder if there is something more complex here than just having the height be negative. Is there a condition before it even gets to the shapes code that is failing?

> LayoutTests/fast/shapes/shape-outside-floats/shape-outside-raster-shape-negative-height.html:17
> +<button>a</button>

Does this have to be a button for this to fail, or would a <span> work? (Or do you even need it at all?)

> LayoutTests/fast/shapes/shape-outside-floats/shape-outside-raster-shape-negative-height.html:20
> +<p style="position: absolute; top: 100px;">

I wouldn't muck around with absolute positioning. Just have this paragraph in here, and dumpAsText() the entire test. You're not gaining anything from it being a ref test except complexity.

[Bem Jones-Bey]

Created attachment 244174 [details]
Cleaned up test case

[Bem Jones-Bey]

Created attachment 244179 [details]
Patch

[Zoltan Horvath]

Comment on attachment 244179 [details]
Patch

Thanks! Looks good!

[WebKit Commit Bot]

Comment on attachment 244179 [details]
Patch

Clearing flags on attachment: 244179

Committed r178054: <http://trac.webkit.org/changeset/178054>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.