Bug #9172


siphash faulty on arm little endian with word align - missing code

Added by prahal (Alban Browaeys) over 10 years ago. Updated almost 9 years ago.

Target version:
ruby -v:
ruby 1.9.3p448 (2013-06-27 revision 41675) [arm-linux-eabihf]


siphash.c check for "little endian+unaligned word access" and
"bigendian". But my arch : armv7-a cortex a9 is little endian word
aligned. This discard the loop that reduce the input below 8 bytes and a
case when the leftover is four bytes.

I found this issue via bundler as it uses the hash of an array (the
collision is "sub-setter".hash and "discoverer".hash has they both share
all other fields (platform and version both at 0.0.2).
I reported it back then as public


  • testcase: "collision.rb"

on arm (odroid u2)

#$ ruby ~/collision.rb

require 'rubygems'

p ["discoverer","0.0.2"), "ruby"].hash
p ["sub-setter","0.0.2"), "ruby"].hash

NB: For now I rebuild with those check for UNALIGNED_WORD_ACCESS removed and
at least I get way less conflict . This is no proper fix though.

Updated by zzak (zzak _) over 10 years ago

  • Status changed from Open to Assigned
  • Assignee set to nobu (Nobuyoshi Nakada)

nobu what do you think?

what is "collision.rb"?

Updated by mame (Yusuke Endoh) over 10 years ago

I confirmed the issue on my BeagleBone Black.

$ ./miniruby -ve 'p ["discoverer".hash, "sub-setter".hash]'
ruby 2.1.0dev (2013-11-28 trunk 43540) [armv7l-linux-eabihf]
[-51053038, -51053038]

I think this is a bug of the siphash-c upstream:

The bug was introduced by nobu, interestingly.

Yusuke Endoh

Actions #3

Updated by nobu (Nobuyoshi Nakada) over 10 years ago

  • Status changed from Assigned to Closed
  • % Done changed from 0 to 100

This issue was solved with changeset r43928.
Alban, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

siphash.c: fix missing condition

Actions #4

Updated by vo.x (Vit Ondruch) almost 9 years ago

  • Backport changed from 1.9.3: UNKNOWN, 2.0.0: UNKNOWN to 2.0.0: REQUIRED, 2.1: DONTNEED, 2.2: DONTNEED

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