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Date: Sun, 24 Jun 2012 23:19:32 -0500
From: "jfoug" <jfoug@....net>
To: <john-dev@...ts.openwall.com>
Subject: RE: Jumbo candidate vs Test Suite
Could this be buffer overwrites, smashing passwords? The TS was written
specifically to cause this form of corruption on formats which require
additional sanity checking, prior to copying passwords.
If you look at the pw.dic file (and others???) there will be some bugus,
unused lines that are long. These are on purpose, and they have flushed out
overwrite issues in many of the jumbo formats.
This often shows up, if you have a format, where there is an array of
candidates worked on at the same time, and these are interspersed (such as
SSE), and part of the input buffer is not written to, because it is not
supposed to ever be modified. Then, if an overlong password is copied into
this buffer, and is longer than it should be, and overflows, then that array
element (and possibly OTHERS), will never find a password again, for the
rest of the run.
When magnum and I were working through a lot of the formats, and designing
the TS, we built it this way, and shook out a LOT of bugs. What you are
listing for numbers IS in the range we were used to seeing (40 to 60% found,
out of the 1500).
The work around for this, was determining just WHAT the max number of bytes
that can be in a password for your format, and making damn sure that you
truncate any password input line longer than this, to that many bytes, so as
to NEVER overflow your pristine buffers.
I do not know if this is the issue, but from experience, it sounds like it
'could' be. IF this IS the case, then the TS is 100% valid, in flushing
the bug out, it IS a bug. You will have users that use 'dirty' wordlists,
which contain some pretty long lines. If you do not properly limit and
protect your format, these dirty input files WILL cause passwords to be
missed.
Jim.
>From: Lukas Odzioba [mailto:lukas.odzioba@...il.com]
>
>2012/6/25 Solar Designer <solar@...nwall.com>:
>> Do you have an idea of what the remaining problem is?
>
>If I had to guess: UTF, Unicode, salt/pass length.
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