[tbb-bugs] #22788 [Applications/Tor Browser]: Tor Browser rendering hangs when downloading large PDFs

Tor Bug Tracker & Wiki blackhole at torproject.org
Sat Jul 1 22:59:21 UTC 2017

#22788: Tor Browser rendering hangs when downloading large PDFs
 Reporter:  teor                      |          Owner:  tbb-team
     Type:  defect                    |         Status:  new
 Priority:  Medium                    |      Milestone:
Component:  Applications/Tor Browser  |        Version:
 Severity:  Normal                    |     Resolution:
 Keywords:                            |  Actual Points:
Parent ID:                            |         Points:
 Reviewer:                            |        Sponsor:

Comment (by teor):

 Replying to [comment:1 cypherpunks]:
 > Isn't this expected since JIT is disabled in those higher security
 settings? Or should there be a whitelist for anything `pdf.js` (at least
 for the Medium security setting)?

 No, this seems to happen to *other* tabs only while the PDF is
 downloading, and not once it's loaded. I don't see why other tabs should
 be affected in 7.0.1 / multiprocess at all. But it seems worse than the
 6.0 series, not better.

 > I agree with you teor, loading PDFs in those security settings can be
 annoyingly slow, especially PDFs containing scans of books. Hopefully with
 [https://trac.torproject.org/projects/tor/ticket/7501#comment:19 FF59esr
 and their switch to Chromium's PDFium we wont get such problems (although
 it's written in C++ = memory unsafe)].

 Could be a while before that happens. And it seems Google has fixed some
 issues in that code and dependent libraries, but they never find them all.

Ticket URL: <https://trac.torproject.org/projects/tor/ticket/22788#comment:2>
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