Bug 37973

Summary: REGRESSION(58040): TextIterator may use freed memory
Product: WebKit Reporter: Shinichiro Hamaji <hamaji>
Component: HTML EditingAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: yuzo
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
Attachments:
Description Flags
Patch v1 darin: review+

Shinichiro Hamaji
Reported 2010-04-21 23:25:57 PDT
http://trac.webkit.org/changeset/58040 modified TextIterator::emitText and it uses RenderText::textWithoutTranscoding which may return String with refcnt==1 . TextIterator::emitText doesn't increment the refcnt of the returned String so the String created by textWithoutTranscoding() will be freed when emitString() finishes. This means we will touch the freed buffer. The test I added in r58040 happened to work for most platforms except chromium-win-debug (maybe because the iterator uses the freed buffer soon after the buffer is freed). My apologies for this bug.
Attachments
Patch v1 (3.65 KB, patch)
2010-04-21 23:28 PDT, Shinichiro Hamaji 		darin: review+
DetailsFormatted DiffDiff
View All Add attachment proposed patch, testcase, etc.
Shinichiro Hamaji
Comment 1 2010-04-21 23:28:32 PDT
Created attachment 54028 [details] Patch v1
Shinichiro Hamaji
Comment 2 2010-04-21 23:29:33 PDT
*** Bug 37907 has been marked as a duplicate of this bug. ***
Darin Adler
Comment 3 2010-04-22 12:56:05 PDT
Comment on attachment 54028 [details] Patch v1 WebCore/editing/TextIterator.h:130 + // Prevent m_textCharacters from being freed. + String m_text; I think this comment is not as clear as it could be, but I don't have any specific suggestions for improving it.
Shinichiro Hamaji
Comment 4 2010-04-22 21:51:57 PDT
Committed r58149: <http://trac.webkit.org/changeset/58149>
Note You need to log in before you can comment on or make changes to this bug.