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

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

 A few comments:

 Are you sure this is using DieHarder as the regular allocator? It's my
 understanding that FF will use mozjemalloc (or jemalloc4) as the
 allocator, and would use the system allocator to allocate space for the
 jemalloc allocator. Which means DieHarder would be allocating memory for
 jemalloc which would be doing all the individual allocations. I think.

 I'll (try to) compare DieHard to PartitionAlloc/Copperhead:
 https://trac.torproject.org/projects/tor/ticket/10281#comment:49

 Some of the features I see in DieHard (I don't think this is exhaustive):
  - 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.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20957#comment:7>
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