[tor-bugs] #20063 [Core Tor/Tor]: Permit sched_yield in sandbox

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#20063: Permit sched_yield in sandbox
----------------------------+------------------------------------
 Reporter:  nickm           |          Owner:  nickm
     Type:  defect          |         Status:  needs_review
 Priority:  Medium          |      Milestone:  Tor: 0.2.9.x-final
Component:  Core Tor/Tor    |        Version:
 Severity:  Normal          |     Resolution:
 Keywords:  review-group-8  |  Actual Points:  0
Parent ID:                  |         Points:  0
 Reviewer:                  |        Sponsor:
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Comment (by asn):

 Hmm, is there a way to reproduce this problem, so that we can test the
 fix?

 I tried running an unpatched tor (git-6abce601f22) with `--enable-
 expensive-hardening` and `Sandbox 1` and encountered no problems with this
 torrc:
 {{{
 Sandbox 1
 SocksPort auto
 }}}
 Tor bootstrapped to 100% no problem.

 All in all, the patch seems like it's doing what is advertised, but I
 actually don't know anything about the workings of seccomp and our
 sandbox. A review by a more experienced person in this area would be
 appreciated.

 One question: Should we only whitelist those syscalls '''if and only if'''
 ASAN is enabled? Because IIUC, now they are whitelisted for all builds.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20063#comment:4>
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