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Date: Wed, 30 Jan 2013 03:12:34 +0100
From: magnum <john.magnum@...hmail.com>
To: john-dev@...ts.openwall.com
Subject: Re: Re: dmg2john

Here might be a fixed version (with a little debug output). However, it still does not crack. But I think the remaining problem is in the formats - I just found out that smaller files does not crack either, neither with this version or the original (this version outputs the same for small files). Not even a 100 MB file works. So we still have issues and I'm still not sure this dmg2john is right for large files (but it seems to be). I actually can't find any version of dmg in the git history that works at all for even a small file.

This version also avoids the almost cute insanity of reading all of the file into memory. That would be a dubious idea for a 300 GB file.

magnum


[ CONTENT OF TYPE application/x-gzip SKIPPED ]





On 30 Jan, 2013, at 1:42 , Jeremiah Grossman <jeremiah@...tehatsec.com> wrote:

> I agree, I think we're experiencing a separate issue.
> 
> With respect to the all-zero issue, this behavior was seen after the segfaulting issue was fixed, with >11GB DMGs, using the most recent git clone several hours ago and adding supplied patches before building.
> 
> In @jmgosney words when helping me debug, "i think changing the print format from %d to %lu will fix the all-zero hash issue."
> 
> I can't speak to the accuracy of this statement though. We did't make any progress.
> 
> 
> From: magnum <john.magnum@...hmail.com>
> 
>> 
>> I have reproduced Jeremiah's problems and I am running 64-bit. Even when using size_t or ULL, I get the two last blobs all-zero. I believe we are looking at a different issue now - the initial one is fixed.
>> 
>> Jeremiah, what was that you wrote about @jmgosney? Did he see this? Was that with a version of this code or some other?
>> 
>> magnum
> 
> On 30 Jan, 2013, at 1:12 , Milen Rangelov <gat3way@...il.com> wrote:
> 
>> Sorry my mistake, long would be 64-bit on x86_64. That's rather strange, only explanation would be it was run on a x86 host.
>> 
>> 
>> On Wed, Jan 30, 2013 at 2:03 AM, magnum <john.magnum@...hmail.com> wrote:
>> On x86_64, long int is 64-bit in Linux as well as OSX. The same goes for GPU by the way. But I should have made it long long anyway. It was just meant as a quick fix/test and I knew Jermeiah was using 64-bit. 
>> 
>> magnum
>> 
>> 
>> On 30 Jan, 2013, at 0:45 , Milen Rangelov <gat3way@...il.com> wrote:
>> 
>>> uint64_t I meant. I don't know if C99 stdint.h stuff is acceptable for jtr though, but it really helps in situations like that. But definitely long is 32-bit int on both x86 and x86_64. Also the compiler likes to do some implicit casts, I would never trust it to do that even if unsigned long long was used. Better thing is assign that to a variable that is definitely 64-bit int, then use it. 
>>> 
>>> On Wed, Jan 30, 2013 at 1:32 AM, Milen Rangelov <gat3way@...il.com> wrote:
>>> I think you should declare an uint64, do the calculations, then pass it to print_hex. Also long is not long long, result would likely not be what you expected.
>>> 
>>> 
>>> On Wed, Jan 30, 2013 at 12:42 AM, magnum <john.magnum@...hmail.com> wrote:
>>> On 29 Jan, 2013, at 23:15 , magnum <john.magnum@...hmail.com> wrote:
>>>> On 29 Jan, 2013, at 22:37 , magnum <john.magnum@...hmail.com> wrote:
>>>> On 29 Jan, 2013, at 2:04 , Solar Designer <solar@...nwall.com> wrote:
>>>>>> On Tue, Jan 29, 2013 at 01:28:57AM +0400, Solar Designer wrote:
>>>>>> I chose to post a different patch in response to Jeremiah's message on
>>>>>> john-users.  That's because there's also a printf format string that
>>>>>> uses "%d", and cno and data_size are also of type int in dmg_fmt_plug.c.
>>>>>> 
>>>>>> The patch that I posted should be good for up to 8 TB.
>>>>> 
>>>> 
>>>> I sent a patch to Jeremiah for trying out. It just adds this (to be used with Solar's patch as well):
>>>> 
>>>> @@ -161,7 +161,7 @@ static void hash_plugin_parse_hash(char *filename)
>>>>              printf("*%d*", header2.encrypted_keyblob_size);
>>>>              print_hex(header2.encrypted_keyblob, header2.encrypted_keyblob_size);
>>>>              printf("*%d*%d*", cno, data_size);
>>>> -             print_hex(chunk + cno * 4096, data_size);
>>>> +             print_hex(chunk + (long)cno * 4096, data_size);
>>>>              printf("*1*");
>>>>              print_hex(chunk, 4096);
>>>>              printf("\n");
>>>> 
>>>> This works for me, except the output is mostly zeros and John can't crack it. Maybe that is the other bug mentioned that I see now?
>>> 
>>> Unfortunately he got the same mostly zero output with the real file. I give up here.
>>> 
>>> magnum
>>> 
>>> 
>> 
>> 
> 
> 
> 


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