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Date: Sat, 15 Aug 2015 21:44:54 +0800
From: Kai Zhao <loverszhao@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: --test-full=0 crashes the Bitcoin format

Hi Alexander,

On Sat, Aug 15, 2015 at 9:32 PM, Kai Zhao <loverszhao@...il.com> wrote:
> Hi Alexander,
>
> On Sat, Aug 15, 2015 at 9:16 PM, Solar Designer <solar@...nwall.com> wrote:
>> Kai,
>>
>> On Sat, Aug 15, 2015 at 04:39:04PM +0800, Kai Zhao wrote:
>>> There maybe at least 1 crash when you run 100 times. As to asan, I think
>>> it does not help. I have not see any asan error.
>>
>> OK.  The lack of ASan errors can help narrow down the search, too - when
>> you review the code, you won't need to spend time on potential issues
>> that would be expected to be detected by ASan.
>>
>> For example, the memory overwrite might be inside calls into libcrypto
>> functions.  Since you're only compiling JtR itself with ASan, those
>> would go undetected.  And yes, compiling OpenSSL with ASan as well
>> might be a way to figure this out.  Or just careful review of the code
>> will do, probably quicker.
>>
>>> It can be reproduced separately almost 1~2 crash with 200 times. I create
>>> an issue:
>>>
>>> https://github.com/magnumripper/JohnTheRipper/issues/1667
>>
>> In there, you wrote:
>>
>> "If your bitcoin.max is not 64, I think you can not reproduce this bug.
>> Maybe you can reproduce it on super."
>>
>> What's "bitcoin.max"?  I can't find it:
>>
>> [solar@...er src]$ fgrep -ri bitcoin.max .
>> [solar@...er src]$
>>
>> Do you possibly mean this format's max_keys_per_crypt?
>
> Yes. My mistake. Updated.
>
>> If so, of course
>> you can make it 64 on your laptop as well: set OMP_NUM_THREADS=32 before
>> running john.  Like this:
>>
>> OMP_NUM_THREADS=32 ./john pwfile --format=bitcoin --wordlist=pwd.lst --skip-self-test
>>
>
> Yes, after set OMP_NUM_THREADS=32, the max_keys_per_crypt is 64. But I
> have not reproduced on my laptop after running about 200 times.

However, when I "set export GOMP_CPU_AFFINITY=0-31" on my laptop which
I did on the super, the john reports error.

$ rm -f ../john.pot && ../john pwfile --format=bitcoin
--skip-self-test --wordlist=pwd.lst
Using default input encoding: UTF-8
Loaded 1 password hash (Bitcoin [SHA512 AES 256/256 AVX2 4x])
Will run 32 OpenMP threads
Press 'q' or Ctrl-C to abort, almost any other key for status
libgomp: Thread creation failed: Invalid argument


Thanks,

Kai

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