Re: patch: initialize randpool with zeroes

>
> Thanks, I've incorporated your patch.
>
> --------------------------------------------------
> From: "zooko" <zookog@...>
> Sent: Thursday, June 04, 2009 1:23 PM
> To: "Crypto++ Users" <cryptopp-users@...>
> Subject: Re: patch: initialize randpool with zeroes
>
>>
>> Jeffrey Walton suggested an improvement to this patch.  Here's the new
>> version, which I'm now using in pycryptopp and which seems to work
>> fine.  I would recommend a patch like this for Crypto++ trunk.  If Wei
>> Dai doesn't want to spend the CPU cycles and to eliminate the
>> (questionable) bits of entropy to be found in uninitialized memory,
>> then perhaps we could guard it with some sort of #define like
>> "PURIFY_CLEAN"/"VALGRIND_CLEAN" or "INITIALIZE_RANDPOOL".
>>
>> Regards,
>>
>> Zooko
>>
>> HACK rgnt1-210-206-dhcp:~/playground/pycryptopp/cryptopp/release-5.6.0-
>> plus-zookopatches$ darcs diff -u -p'initialize the randpool'
>> Thu Jun  4 07:41:58 MDT 2009  zooko@...
>>  * initialize the randpool with zeroes instead of using whatever bits
>> were there
>>  This makes valgrind stop complaining about using uninitialized
>> memory.  There are other ways to make valgrind stop complaining, such
>> as by explicitly telling it "See these here bytes?  Pretend from now
>> on that they are initialized.", but I don't like using uninitialized
>> memory for my randpool anyway.  If my randpool is broken, I would like
>> for it to start giving the exact same output time after time (or a
>> short cycle, or a selection from a small set, or whatever), so that
>> the users and developers can more quickly detect the problem, rather
>> than rely for my security on the values in the uninitialized memory,
>> which might not be all that unpredictable.
>> diff -rN -u old-release-5.6.0-plus-zookopatches/c5/randpool.cpp new-
>> release-5.6.0-plus-zookopatches/c5/randpool.cpp
>> --- old-release-5.6.0-plus-zookopatches/c5/randpool.cpp 2009-06-04
>> 14:18:46.000000000 -0600
>> +++ new-release-5.6.0-plus-zookopatches/c5/randpool.cpp 2009-06-04
>> 14:18:46.000000000 -0600
>> @@ -19,6 +19,8 @@
>> RandomPool::RandomPool()
>>        : m_pCipher(new AES::Encryption), m_keySet(false)
>> {
>> +       memset(m_key, 0, m_key.size());
>> +       memset(m_seed, 0, m_seed.SizeInBytes());
>> }
>>
>> void RandomPool::IncorporateEntropy(const byte *input, size_t length)
>>
>>
>
> >
>