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Issue 908041 link

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Issue metadata

Status: Duplicate
Owner:
Closed: Dec 3
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Linux
Pri: 2
Type: Bug



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Null-dereference READ in blink::SliderThumbElement::SetPositionFromValue

Project Member Reported by ClusterFuzz, Nov 23

Issue description

Detailed report: https://clusterfuzz.com/testcase?key=5118019019472896

Fuzzer: ochang_domfuzzer
Job Type: linux_asan_content_shell_drt
Platform Id: linux

Crash Type: Null-dereference READ
Crash Address: 0x000000000010
Crash State:
  blink::SliderThumbElement::SetPositionFromValue
  blink::RangeInputType::UpdateView
  blink::RangeInputType::SanitizeValueInResponseToMinOrMaxAttributeChange
  
Sanitizer: address (ASAN)

Regressed: https://clusterfuzz.com/revisions?job=linux_asan_content_shell_drt&range=554016:554019

Reproducer Testcase: https://clusterfuzz.com/download?testcase_id=5118019019472896

Issue filed automatically.

See https://github.com/google/clusterfuzz-tools for more information.
 
Project Member

Comment 1 by ClusterFuzz, Nov 23

Components: Blink>Forms
Labels: Test-Predator-Auto-Components
Automatically applying components based on crash stacktrace and information from OWNERS files.

If this is incorrect, please apply the Test-Predator-Wrong-Components label.
Project Member

Comment 2 by ClusterFuzz, Nov 23

Labels: Test-Predator-Auto-Owner
Owner: futhark@chromium.org
Status: Assigned (was: Untriaged)
Automatically assigning owner based on suspected regression changelist https://chromium.googlesource.com/chromium/src/+/9aa33c1d8d269d44490d2114736eb57eded120ab ([Squad] Propagate thumb appearance during style recalc.).

If this is incorrect, please let us know why and apply the Test-Predator-Wrong-CLs label. If you aren't the correct owner for this issue, please unassign yourself as soon as possible so it can be re-triaged.
Cc: futhark@chromium.org
Labels: -Pri-1 Pri-2
Owner: tkent@chromium.org
This crashes because the C++ has an assumption about which elements exist in the UA shadow for the input type=range. Normally, the browser has full control over the UA shadow, but this fuzzer case is triggered when running with --expose-internals-for-testing and nuking the UA shadow internals from javascript.

Ideally, we should not expose the UA shadow through internals.shadowRoot and rewrite all tests using it as unit tests.

This is probably not the only UA element we use without null checking.

tkent@ I don't know if this is a WontFix, but I think adding null checks everywhere for UA shadow code is not the right solution.



Mergedinto: 580734
Status: Duplicate (was: Assigned)

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