No, please don't do that. Alloca is being used to find some stack space that 
isn't cache-aliased with static lookup tables, in order to defend against 
timing attacks. It's easy to just apply Zooko's fix. I'll also get this fixed 
in the next release.
  From: Rafael Vargas 
  Sent: Thursday, September 17, 2009 2:45 PM
  To: Kevin Nasman 
  Cc: Crypto++ Users 
  Subject: Re: rijndael.cpp alloca issue using make on mingw


  I guess you can change from "alloca" to "malloc", but you have to remember to 
free the memory before the return statement.
  -- 
  Vargas



  On Thu, Sep 17, 2009 at 18:21, Kevin Nasman <[email protected]> wrote:

    I read about that fix and tried it before, but sadly it does not fix my 
install. I do not have alloca in any library, stdlib included. So the fix for 
an apple compiler does not work for the winxp mingw compiler tool set.

    Again, I am wondering what is wrong with using malloc vs alloca. Why is 
this the only spot in the whole crypto library that alloca is being used? Can 
it be changed to malloc given the same function ins/outs and then there would 
be no need for sun/apple specific exceptions.

    Thanks for your time,
    K 



    On Tue, Sep 15, 2009 at 12:19 PM, Zooko Wilcox-O'Hearn <[email protected]> 
wrote:

      Here is a patch that fixes that issue for me:

      
http://allmydata.org/trac/pycryptopp/changeset?new=622%40cryptopp&old=620%40cryptopp

      This patch was initially committed to the pycryptopp repository in two 
steps:

      http://allmydata.org/trac/pycryptopp/changeset/621/cryptopp
      http://allmydata.org/trac/pycryptopp/changeset/622/cryptopp

      Regards,

      Zooko







  

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