This issue is a security regression. If you are not able to fix this quickly, please revert the change that introduced it.

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Hi kojii@, can you take a look at this / retriage as necessary in the CSS Ruby layout module?

Chris, could you help me to find someone familiar with -webkit-clip-path?

In CompositedLayerMapping::updateChildClippingMaskLayerGeometry() and a few other places, toLayoutBox(layoutObject()) fails because LayoutRubyAsInline is not LayoutBox.

The test still hits the same problem when I changed <ruby> to <span> by calling toLayoutBox() on LayoutInline.

I'm not sure if we're supposed to create layers for LayoutInline. Suppressing it may fix the problem but the spec says -webkit-clip-path applies to all elements. If the root cause is in layout code, I'm happy to look further, inline/ruby are my favorites, but having advises from clip-path experts would help.

Seems like this is very similar to https://bugs.chromium.org/p/chromium/issues/detail?id=675176.  Stacks very close, just slightly different at the top.

Feel free to combine if you agree.

ClusterFuzz has detected this issue as fixed in range 440808:440829.

Detailed report: https://cluster-fuzz.appspot.com/testcase?key=5188038243385344

Fuzzer: ifratric-browserfuzzer-v3
Job Type: linux_cfi_chrome
Platform Id: linux

Crash Type: Bad-cast
Crash Address: 0x7f3ece069fd8
Crash State:
  Bad-cast to blink::LayoutBox from blink::LayoutRubyAsInline
  blink::LayoutObject::isRubyRun
  blink::LayoutRubyAsInline::addChild
  
Recommended Security Severity: High

Regressed: https://cluster-fuzz.appspot.com/revisions?job=linux_cfi_chrome&range=437599:437697
Fixed: https://cluster-fuzz.appspot.com/revisions?job=linux_cfi_chrome&range=440808:440829

Minimized Testcase (0.28 Kb): https://cluster-fuzz.appspot.com/download/AMIfv95jgoq_PwOHCJmbylA68qWPI5ct1cO9prxtbtg6H3CcTevKKw7MfgwK_OEsPKwiZJK6OBAUoWB229QwQ4JDZ890ayymnBGU5lj_roPBtIVgLGVM8DPMWYZOshfr_0SD2oizFEJr31IUO-tgRuK_dhCtCU2_uA?testcase_id=5188038243385344

See https://dev.chromium.org/Home/chromium-security/bugs/reproducing-clusterfuzz-bugs for more information.

If you suspect that the result above is incorrect, try re-doing that job on the test case report page.

ClusterFuzz testcase 5188038243385344 is verified as fixed, so closing issue.

If this is incorrect, please add ClusterFuzz-Wrong label and re-open the issue.

This bug has been closed for more than 14 weeks. Removing security view restrictions.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot