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Message-ID: <CABtNtWF6Bz4TKryN9hPnFW+G-AjOazWRZt=P+on0aO6Uf7ocaw@mail.gmail.com>
Date: Sat, 15 Aug 2015 21:32:52 +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 9:16 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.
>
> Kai, you're currently running two instances of john on super:
>
> kai 28475 1159 0.0 2413324 7392 ? Sl 05:50 7207:40 ./john --test-full=0 --format=bitcoin
> kai 31899 825 0.0 2413324 7360 ? Sl 06:29 4806:53 ./john --test-full=0 --format=bitcoin
>
> bringing load average to 37.00. What are these trying to achieve?
> Suppose one of them or both would crash, would this help in any way?
>
Sorry, the two process maybe are zombie process. I did not notice that
and I just killed them.
Thanks,
Kai
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