[tbb-bugs] #20957 [Applications/Tor Browser]: Get DieHarder working with Tor Browser

Tor Bug Tracker & Wiki blackhole at torproject.org
Sun Jul 9 06:00:46 UTC 2017

#20957: Get DieHarder working with Tor Browser
 Reporter:  arthuredelstein           |          Owner:  tbb-team
     Type:  defect                    |         Status:  needs_revision
 Priority:  Medium                    |      Milestone:
Component:  Applications/Tor Browser  |        Version:
 Severity:  Normal                    |     Resolution:
 Keywords:  tbb-hardened              |  Actual Points:
Parent ID:  #20955                    |         Points:
 Reviewer:                            |        Sponsor:

Comment (by cypherpunks):

 Replying to [comment:7 tom]:
 > I'll (try to) compare DieHard to PartitionAlloc/Copperhead:
 > Some of the features I see in DieHard (I don't think this is
 >  - randomized freelist selection
 >  - randomized allocation placement (to some degree I assume)
 >  - random bytes written on free
 > I don't believe they have any partitioning support. In general, it seems
 DieHarder is somewhat comparable to Coppherhead's allocator. It may have
 or lack a few small features that the other has. The lack of partitioning
 is the main strike against it.

 Perhaps someone should consult strcat (the Copperhead developer) on this
 subject. I have a feeling that he will be able to point out downfalls in
 the DieHarder approach, as well as the future plans for the Copperhead
 allocator (which is an improved hybrid between bionic's malloc and
 OpenBSD's malloc). I believe strcat will be the best person to ask, as he
 is very familiar with memory allocators (e.g. he's planning on upstreaming
 a hardened slab allocator to Linux), and he's often very willing to talk.

 Memory allocator hardening is a tricky issue, subject to a lot of subtle

Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20957#comment:10>
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