openwall / openwall/john

argon2-opencl fails on CPU and MIC

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#5,417 17 comments 0 reactions 0 assignees View on GitHub

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bug
Dominant language
C
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Description

A known shortcoming/bug of the argon2-opencl format is that it fails self-test on CPU(-like) devices, as tested with ancient Intel OpenCL and AMD APP SDK that we have on our online dev boxes and with recent Intel OpenCL that @alainesp has on his laptop. We don't know exactly why - a guess is this has something to do with our usage of local memory.

The format works on most GPUs, the only exception identified so far being Intel HD Graphics, where it also fails.

The failures on CPUs and Intel GPU are FAILED (cmp_one(1)). The failure on MIC includes segfaults.

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Research direction

The issue concerns the argon2-opencl format and reports self-test failures on CPU-like devices, Intel HD Graphics, and MIC, including MIC segfaults. Start by reproducing the self-test on the affected device types and investigate the suspected local-memory usage. Done means the format passes self-test on CPU, Intel GPU, and MIC without segfaults.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
cryptography
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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