tls_policy.cpp

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/*
* Policies for TLS
* (C) 2004-2010 Jack Lloyd
*
* Released under the terms of the Botan license
*/
 
#include <botan/tls_policy.h>
#include <botan/tls_exceptn.h>
 
namespace Botan {
 
/*
* Return allowed ciphersuites
*/
std::vector<u16bit> TLS_Policy::ciphersuites() const
   {
   return suite_list(allow_static_rsa(), allow_edh_rsa(), allow_edh_dsa());
   }
 
/*
* Return allowed ciphersuites
*/
std::vector<u16bit> TLS_Policy::suite_list(bool use_rsa,
                                           bool use_edh_rsa,
                                           bool use_edh_dsa) const
   {
   std::vector<u16bit> suites;
 
   if(use_edh_dsa)
      {
      suites.push_back(TLS_DHE_DSS_WITH_AES_256_CBC_SHA);
      suites.push_back(TLS_DHE_DSS_WITH_AES_128_CBC_SHA);
      suites.push_back(TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA);
      suites.push_back(TLS_DHE_DSS_WITH_SEED_CBC_SHA);
      }
 
   if(use_edh_rsa)
      {
      suites.push_back(TLS_DHE_RSA_WITH_AES_256_CBC_SHA);
      suites.push_back(TLS_DHE_RSA_WITH_AES_128_CBC_SHA);
      suites.push_back(TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA);
      suites.push_back(TLS_DHE_RSA_WITH_SEED_CBC_SHA);
      }
 
   if(use_rsa)
      {
      suites.push_back(TLS_RSA_WITH_AES_256_CBC_SHA);
      suites.push_back(TLS_RSA_WITH_AES_128_CBC_SHA);
      suites.push_back(TLS_RSA_WITH_3DES_EDE_CBC_SHA);
      suites.push_back(TLS_RSA_WITH_SEED_CBC_SHA);
      //suites.push_back(TLS_RSA_WITH_RC4_128_SHA);
      //suites.push_back(TLS_RSA_WITH_RC4_128_MD5);
      }
 
   if(suites.size() == 0)
      throw TLS_Exception(INTERNAL_ERROR,
                          "TLS_Policy error: All ciphersuites disabled");
 
   suites.push_back(TLS_NO_RENEGOTIATION_SCSV);
 
   return suites;
   }
 
/*
* Return allowed compression algorithms
*/
std::vector<byte> TLS_Policy::compression() const
   {
   std::vector<byte> algs;
   algs.push_back(NO_COMPRESSION);
   return algs;
   }
 
/*
* Choose which ciphersuite to use
*/
u16bit TLS_Policy::choose_suite(const std::vector<u16bit>& c_suites,
                                bool have_rsa,
                                bool have_dsa) const
   {
   bool use_static_rsa = allow_static_rsa() && have_rsa;
   bool use_edh_rsa = allow_edh_rsa() && have_rsa;
   bool use_edh_dsa = allow_edh_dsa() && have_dsa;
 
   std::vector<u16bit> s_suites = suite_list(use_static_rsa, use_edh_rsa,
                                             use_edh_dsa);
 
   for(size_t i = 0; i != s_suites.size(); ++i)
      for(size_t j = 0; j != c_suites.size(); ++j)
         if(s_suites[i] == c_suites[j])
            return s_suites[i];
 
   return 0;
   }
 
/*
* Choose which compression algorithm to use
*/
byte TLS_Policy::choose_compression(const std::vector<byte>& c_comp) const
   {
   std::vector<byte> s_comp = compression();
 
   for(size_t i = 0; i != s_comp.size(); ++i)
      for(size_t j = 0; j != c_comp.size(); ++j)
         if(s_comp[i] == c_comp[j])
            return s_comp[i];
 
   return NO_COMPRESSION;
   }
 
/*
* Return the group to use for empheral DH
*/
DL_Group TLS_Policy::dh_group() const
   {
   return DL_Group("modp/ietf/1024");
   }
 
}