[Botan-devel] Issues with 1.2.4 and the workarounds

[Jeff B <je...@ho...>]

Hello, if you missed my posts yesterday, here's the scoop:  I'm an 
experienced programmer but I'm new to encryption and the Botan library, and 
I'm currently evaluating Botan to use in a project I'm working on.  I've got 
the 1.2.4 sources and I'm trying to build using Visual Studio .NET 2003 on 
Windows and CodeWarrior Pro 8.3 on MacOS X, but I'm having troubles building 
on Windows and running on Mac...


Issue #1: Windows compile problem solved/workaround. The following in 
get_ciph.cpp, line 87
      Invalid_Combination(const std::string& mode, const std::string& pad) :
         Exception("Invalid mode/padding pair: " + mode + "/" + pad) {}
Doesn't compile.  If you comment out mode and pad and change it to
      Invalid_Combination(const std::string& mode, const std::string& pad) :
         Exception("Invalid mode/padding pair: " /*+ mode + "/" + pad*/) {}
It's able to compile and run (I've built a console app using the 
rsa_kgen.cpp file.



Issue #2: In my test project (build on rsa_kgen.cpp), 
Botan::Init::Initialize() was throwing because total_bits (generated from 
Global_RNG::seed()) was zero.  When I reported the problem yesterday, I had 
indicated that it was a Mac problem... Turns out it's a Windows problem as 
well.

I used "perl configure.pl msvc-windows-i486" to configure Botan on Windows.  
When I ran the Windows version, Botan::Init::Initialize() was throwing, just 
like it was on the mac.

Botan::Global_RNG::seed(), without any of the BOTAN_EXT_ENTROPY_SRC_EGD, 
BOTAN_EXT_ENTROPY_SRC_CAPI, etc...  defined, is the whittled down to the 
following:


u32bit seed(bool slow_poll, u32bit bits_to_get)
   {
   u32bit bits = 0;

   bits += poll_es<File_EntropySource>(slow_poll);

   if(bits >= bits_to_get) return bits;

   if(bits >= bits_to_get) return bits;

   return bits;
   }
}


Well, poll_es<File_EntropySource>(slow_poll) tries to read "/dev/urandom" 
and "/dev/random" for random source bits, but neither of these files exist 
on either of my machines (Mac or Windows), so 
File_EntropySource::slow_poll() isn't placing anything into the buffer, 
which causes poll_es() to return zero bits, which in turn causes 
initialize() to throw.

When I added #define BOTAN_EXT_ENTROPY_SRC_WIN32 to the Windows project, the 
same code got executed (and urandom and random weren't found), but the 
addition of
   bits += poll_es<Win32_EntropySource>(slow_poll);
called the Windows-specific code (Win32_EntropySource::do_fast_poll() and 
Win32_EntropySource::do_slow_poll()) and added bits to the seed and 
everything worked (YEA!)


OK, now, a question:  Is this a known issue?  From what I can tell, you need 
to either have a "urandom" or "random" file present, or a platform-specific 
#define (like BOTAN_EXT_ENTROPY_SRC_WIN32 ) in order for it to work.  If 
this is in the docs, I apologies... I missed it.



Jeff

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