Bug 105393 – ::first-letter { overflow: -webkit-paged-y } causes crash

• Status: RESOLVED
• Resolution: FIXED
• Component: CSS

[Takashi Sakamoto]

Reported by fuzzer: https://cluster-fuzz.appspot.com/testcase?key=102884484

The following is a stack trace in the above report:

/mnt/scratch0/clusterfuzz/slave-bot/builds/symbolized/debug/asan-linux-debug-154320/DumpRenderTree

ASAN:SIGSEGV
=================================================================
==32198== ERROR: AddressSanitizer crashed on unknown address 0x000000000060 (pc 0x7f435c2a3d32 sp 0x7fff95826a80 bp 0x7fff95826bd0 T0)
AddressSanitizer can not provide additional info.
    #0 0x7f435c2a3d31 in WebCore::QualifiedName::matches(WebCore::QualifiedName const&) const third_party/WebKit/Source/WebCore/dom/QualifiedName.h:85
    #1 0x7f435c2a3b7e in WebCore::Element::hasTagName(WebCore::QualifiedName const&) const third_party/WebKit/Source/WebCore/dom/Element.h:222
    #2 0x7f436690eb52 in WebCore::StyleResolver::adjustRenderStyle(WebCore::RenderStyle*, WebCore::RenderStyle*, WebCore::Element*) third_party/WebKit/Source/WebCore/css/StyleResolver.cpp:2240
    #3 0x7f43669259bb in WebCore::StyleResolver::pseudoStyleForElement(WebCore::PseudoId, WebCore::Element*, WebCore::RenderStyle*) third_party/WebKit/Source/WebCore/css/StyleResolver.cpp:1956
    #4 0x7f4368e8379e in WebCore::RenderObject::getUncachedPseudoStyle(WebCore::PseudoId, WebCore::RenderStyle*, WebCore::RenderStyle*) const third_party/WebKit/Source/WebCore/rendering/RenderObject.cpp:2688
    #5 0x7f4368e993b8 in WebCore::RenderObject::getCachedPseudoStyle(WebCore::PseudoId, WebCore::RenderStyle*) const third_party/WebKit/Source/WebCore/rendering/RenderObject.cpp:2659
    #6 0x7f4368e98993 in WebCore::RenderObject::firstLineStyleSlowCase() const third_party/WebKit/Source/WebCore/rendering/RenderObject.cpp:2637
    #7 0x7f43684e16c9 in WebCore::RenderObject::firstLineStyle() const third_party/WebKit/Source/WebCore/rendering/RenderObject.h:728
    #8 0x7f43684df4bc in WebCore::RenderObject::style(bool) const third_party/WebKit/Source/WebCore/rendering/RenderObject.h:729
    #9 0x7f4368859392 in WebCore::RenderBlock::LineBreaker::nextLineBreak(WebCore::BidiResolver<WebCore::InlineIterator, WebCore::BidiRun>&, WebCore::LineInfo&, WebCore::RenderBlock::RenderTextInfo&, WebCore::RenderBlock::FloatingObject*, unsigned int) third_party/WebKit/Source/WebCore/rendering/RenderBlockLineLayout.cpp:2407
    #10 0x7f436884c357 in WebCore::RenderBlock::layoutRunsAndFloatsInRange(WebCore::LineLayoutState&, WebCore::BidiResolver<WebCore::InlineIterator, WebCore::BidiRun>&, WebCore::InlineIterator const&, WebCore::BidiStatus const&, unsigned int) third_party/WebKit/Source/WebCore/rendering/RenderBlockLineLayout.cpp:1328
    #11 0x7f4368845ec9 in WebCore::RenderBlock::layoutRunsAndFloats(WebCore::LineLayoutState&, bool) third_party/WebKit/Source/WebCore/rendering/RenderBlockLineLayout.cpp:1271
    #12 0x7f436886a0eb in WebCore::RenderBlock::layoutInlineChildren(bool, WebCore::FractionalLayoutUnit&, WebCore::FractionalLayoutUnit&) third_party/WebKit/Source/WebCore/rendering/RenderBlockLineLayout.cpp:1600
    #13 0x7f4368648c8b in WebCore::RenderBlock::layoutBlock(bool, WebCore::FractionalLayoutUnit) third_party/WebKit/Source/WebCore/rendering/RenderBlock.cpp:1531

The reason why this crash occurs is that we forget to check whether "e != null" or not before e->hasTagName(...) in StyleResolver::adjustRenderStyle.

[Takashi Sakamoto]

Created attachment 180104 [details]
Patch

[WebKit Review Bot]

Comment on attachment 180104 [details]
Patch

Clearing flags on attachment: 180104

Committed r138451: <http://trac.webkit.org/changeset/138451>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.