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Do not use mmap by default. #579

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Do not use mmap by default. #579

wants to merge 1 commit into from

Commits on Aug 22, 2017

  1. Do not use mmap by default. 

    Reading memory-mapped files is inherently insecure because no safe
mechanism exists to prevent out-of-bounds reads if the file gets
truncated. The POSIX standard says “An implementation may deliver
SIGBUS signals when a reference would cause an error in the mapped
object, such as out-of-space condition.” so it seems safer to disable
mmap by default.

The bug is simply triggered using this command:

    # dd of=zob count=0 seek=16G; (sleep 0.1; truncate -s1 zob)&; rg -a lol zob
    [2]    15028 bus error  rg -a lol zob
    @samhocevar
    samhocevar committed Aug 22, 2017
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