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Date: Mon, 25 May 2015 22:19:17 -0700
From: <writeonce@...ipix.org>
To: john-dev@...ts.openwall.com, "Rich Felker" <dalias@...c.org>
Subject: RE: update: JtR for Windows using musl libc

On 05/25/2015 11:20 PM, Solar Designer wrote:> On Mon, May 25, 2015 at
11:01:47PM -0400, Rich Felker wrote:
>> The argument registers for integer arguments are completely different
>> (rcx,rdx,r8,r9 vs rdi,rsi,rdx,rcx,r8,r9) so I would expect the
>> behavior to be nonsense.
> 
> Oh, this must be it.  rdi for the argument was my first thought, but I
> wrongly recalled that all of these functions use it.  I just took a
> look, and the asm version of DES_bs_crypt_25 does not actually use its
> argument (even though it's called with one, since the C implementation
> sometimes uses it).  So this is why descrypt and tripcode passed test.
> 
>> Note that there's a GCC attribute, __sysv_abi__, that could be used to
>> call the standard ABI asm code from a caller that's using the MS ABI.
>> That would be a way to reuse the asm unmodified rather than having to
>> wrap it or write a special version for Windows. The attribute just
>> needs to be put on the declarations of the asm functions in the
>> translation units they're called from.
> 
> midipix may try that.
> 
> Alexander
> 
> 

I have now looked at x86-64.h and DES_bs.h and have added a few sysv_abi
hints which did not change the outcome. My understanding is that someone
familiar with JtR would have an easier time debugging this.

As for performance: at some point I commented out the code in times(2)
which converts NT measures (units of 100ns) to clock_t (1/100 sec)...
the test was run natively on i3-2100 pc, and with the fixed __sys_times
the numbers now finally seem correct. As an aside, an additional factor
that might slow things down a bit (but nothing like *100000) is that the
entire stack (libc, runtime library, john) is built with -g3 -O0.

midipix


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