john-users - Re: Parallalizing John the Ripper

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Date: Wed, 31 May 2006 11:44:24 +0200
From: "Otheus (aka Timothy J. Shelling)" <otheus@...il.com>
To: john-users@...ts.openwall.com
Subject: Re: Parallalizing John the Ripper

On 5/31/06, Solar Designer <solar@...nwall.com> wrote:
>
> On Tue, May 30, 2006 at 03:33:37AM +0200, Otheus (aka Timothy J. Shelling)
> wrote:
> > My problem with john.pot getting corrupted was fixed by adding
> -DOS_FLOCK to
> > the CFLAGS for linux.
>
> That's weird, for two reasons:


Make it three reasons.

I added -DOS_FLOCK to the linux-ppc64 make target, not the x86-64!!

1. The default arch.h for sane platforms defines OS_FLOCK already.


indeed.

2. logger.c uses direct write(2) syscalls on pieces of data no larger
> than POT_BUFFER_SIZE and consisting of a whole number of entries (no
> partial lines).  The default POT_BUFFER_SIZE is 4 KB - the same as or
> smaller than the page size on most architectures.  So even when OS_FLOCK
> is not set, concurrent writes to john.pot by multiple instances of John
> will most likely not result in john.pot getting corrupted.


agreed.  Nevertheless, it WAS getting corrupted.   I will see if I can track
it down in the next few weeks.





-- 
Otheus
otheus@...il.com
+43.650.790.2571