[tor-bugs] #20976 [Applications/Tor Browser Sandbox]: Official `sandboxed-tor-browser` binaries break with PaX MPROTECT.

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#20976: Official `sandboxed-tor-browser` binaries break with PaX MPROTECT.
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 Reporter:  yawning                           |          Owner:  yawning
     Type:  defect                            |         Status:  new
 Priority:  Medium                            |      Milestone:
Component:  Applications/Tor Browser Sandbox  |        Version:
 Severity:  Normal                            |     Resolution:
 Keywords:                                    |  Actual Points:
Parent ID:                                    |         Points:
 Reviewer:                                    |        Sponsor:
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Comment (by cypherpunks):

 Do you have any more information about the crash? What library shows a
 denied RWX mmap in the kernel log? What do the logs from `strace -fe
 trace=memory,process` say?

 I really doubt it has anything to do with a deterministic build setup. The
 only things `PAX_MPROTECT` does are:

 * Prevents creation of RWX mappings
 * Prevents creation of RX anonymous mappings
 * Prevents making a non-executable mapping executable
 * Prevents making an RX mapping writable with the exception of performing
 relocations on a non-PIC library

 Deterministic shouldn't change the behavior of Firefox itself in a way
 that would violate any of these. My guess is you're linking in a library
 which for some reason tries to create an RWX mapping. But given that the
 current ESR breaks due to creating RWX mappings for JIT, I haven't even
 played with it myself.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20976#comment:2>
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