Bug 18352

Summary: crash loading malicious font
Product: WebKit Reporter: John Daggett <jdaggett>
Component: Layout and RenderingAssignee: mitz
Status: RESOLVED FIXED    
Severity: Major CC: ap, gavin.sharp, mitz
Priority: P2 Keywords: InRadar
Version: 525.x (Safari 3.1)   
Hardware: Mac   
OS: OS X 10.4   
Attachments:
Description Flags
testcase, uses malicious downloadable font
none
crash reporter output when crash does occur none

John Daggett
Reported 2008-04-07 22:42:56 PDT
Wrote a simple testcase that uses the malicious font described here: http://cg.scs.carleton.ca/~luc/opentypecrash.html Running with Safari 3.1 latest, the page *sometimes* crashes, other times it just displays Last Resort glyphs for the text assigned the style that uses the bad font. Doesn't seem to occur with WebKit latest builds, although I'm guessing that's more luck than anything else.
Attachments
testcase, uses malicious downloadable font (818 bytes, text/html)
2008-04-07 22:43 PDT, John Daggett 		no flags
Details
crash reporter output when crash does occur (24.70 KB, text/plain)
2008-04-07 22:45 PDT, John Daggett 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
John Daggett
Comment 1 2008-04-07 22:43:48 PDT
Created attachment 20393 [details] testcase, uses malicious downloadable font
John Daggett
Comment 2 2008-04-07 22:45:25 PDT
Created attachment 20394 [details] crash reporter output when crash does occur
John Daggett
Comment 3 2008-04-07 22:55:25 PDT
Doesn't crash with Safari 3.1 525.13 Windows
mitz
Comment 4 2008-04-09 00:20:08 PDT
Can’t reproduce on Leopard, but the crash report is from Tiger.
mitz
Comment 5 2008-04-09 22:49:57 PDT
Confirmed on Mac OS X 10.4.11. Seems like ATS refuses to actually activate the font, but WebCore may not be handling this well.
mitz
Comment 6 2008-04-09 22:50:31 PDT
<rdar://problem/5854517>
John Daggett
Comment 7 2008-04-10 00:09:02 PDT
Note that the font has bad glyph data, the bug is caused by the specific charstring used for the 'o' glyph. So my guess is that ATS will probably activate the font but will run into problems when attempting to measure and/or rasterize the actual glyphs. My guess is that ATSUI code is not properly handling some ATS-related error and accessing random memory, hence the error.
mitz
Comment 8 2008-05-21 14:51:52 PDT
Fixed in <http://trac.webkit.org/changeset/33977>.
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