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Date: Tue, 22 Apr 2014 11:07:28 -0500
From: "jfoug" <jfoug@....net>
To: <john-dev@...ts.openwall.com>
Subject: RE: New functionality added to bleeding (and a few changes we as devs need to make)

With MEMDBG_ON set, this is a 'normal' exit:

 

Testing: SSH (one 2048-bit RSA and one 1024-bit DSA key) [RSA/DSA 32/32]...
PASS

Testing: wpapsk, WPA/WPA2 PSK [PBKDF2-SHA1 32/32]... PASS

Testing: ZIP, WinZip [PBKDF2-SHA1 32/32]... PASS

All 360 formats passed self-tests!

At Program Exit

MemDbg_Validate level 0 checking Passed

 

 

Here, I commented out the free of salt and binary in fmt_self_test function.
This is what memdbg code now shows:

 

$ ../run/john -test=0 -form=zip

Testing: ZIP, WinZip [PBKDF2-SHA1 32/32]... PASS

Mem leak: 129 bytes, alloc_num 53, file formats.c, line 498

Mem leak: 1 bytes, alloc_num 52, file formats.c, line 498

 

------------------------------

MEMDBG: allocation information:

   current normal alloc mem (leaks)  130  max normal mem allocated: 69640

   current 'tiny' alloc mem (leaks)    0  max  tiny  mem allocated: 1419812

 

Index : alloc# :   Size : File(Line)  [first 20 bytes, or size of bytes]

0     : 53     :    129 : formats.c(498)  ......wp..\....^....

1     : 52     :      1 : formats.c(498)  .

At Program Exit

MemDbg_Validate level 0 checking Passed

 

 

This shows the leaked data, it's size, and where in code it was allocated,
and a little bit of the data.  NOTE, with these free's commented out, if I
would have run a simple -test=0 without doing a specific format, then the
amount of leaks would have been much more, but probably they all would have
originated from the line 498, formats.c.

 

This is not the 'only' think memdbg finds.  It also finds over/underrun of
data AT runtime (when the free happens).  This may not help if the program
cores prior to the call to free, but this HAS also caught some nasty little
nits which were in some of the early WIP formats, that were having problems.

 

Jim.


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