Server side PSK kex

4 files changed, 37 insertions, 13 deletions

diff --git a/src/tls/c_kex.cpp b/src/tls/c_kex.cpp
index 9f492c5a5..f5afcc100 100644
--- a/src/tls/c_kex.cpp
+++ b/src/tls/c_kex.cpp
@@ -185,21 +185,38 @@ Client_Key_Exchange::Client_Key_Exchange(Record_Writer& writer,
 * Read a Client Key Exchange message
 */
 Client_Key_Exchange::Client_Key_Exchange(const MemoryRegion<byte>& contents,
-                                         const Ciphersuite& suite,
-                                         Protocol_Version using_version)
+                                         const Handshake_State* state,
+                                         Credentials_Manager& creds)
    {
-   if(suite.kex_algo() == "RSA" && using_version == Protocol_Version::SSL_V3)
+   const std::string kex_algo = state->suite.kex_algo();
+
+   if(kex_algo == "RSA" && state->version == Protocol_Version::SSL_V3)
       key_material = contents;
    else
       {
       TLS_Data_Reader reader(contents);
 
-      if(suite.kex_algo() == "RSA" || suite.kex_algo() == "DH")
+      if(kex_algo == "RSA" || kex_algo == "DH")
          key_material = reader.get_range<byte>(2, 0, 65535);
-      else if(suite.kex_algo() == "ECDH")
+      else if(kex_algo == "ECDH")
          key_material = reader.get_range<byte>(1, 1, 255);
+      else if(kex_algo == "PSK")
+         {
+         const std::string psk_identity = reader.get_string(2, 0, 65535);
+
+         SymmetricKey psk = creds.psk("tls-server",
+                                      state->client_hello->sni_hostname(),
+                                      psk_identity);
+
+         MemoryVector<byte> zeros(psk.length());
+
+         append_tls_length_value(key_material, zeros, 2);
+         append_tls_length_value(key_material, psk.bits_of(), 2);
+
+         pre_master = key_material;
+         }
       else
-         throw Internal_Error("Unknown client key exch type " + suite.kex_algo());
+         throw Internal_Error("Client_Key_Exchange received unknown kex type " + kex_algo);
       }
    }
 
@@ -212,7 +229,11 @@ Client_Key_Exchange::pre_master_secret(RandomNumberGenerator& rng,
    {
    const std::string kex_algo = state->suite.kex_algo();
 
-   if(kex_algo == "RSA")
+   if(kex_algo == "PSK")
+      {
+      return key_material;
+      }
+   else if(kex_algo == "RSA")
       {
       BOTAN_ASSERT(state->server_certs && !state->server_certs->cert_chain().empty(),
                    "No server certificate to use for RSA");
diff --git a/src/tls/tls_messages.h b/src/tls/tls_messages.h
index 41ab6ece4..b29aac600 100644
--- a/src/tls/tls_messages.h
+++ b/src/tls/tls_messages.h
@@ -223,8 +223,9 @@ class Client_Key_Exchange : public Handshake_Message
                           RandomNumberGenerator& rng);
 
       Client_Key_Exchange(const MemoryRegion<byte>& buf,
-                          const Ciphersuite& suite,
-                          Protocol_Version using_version);
+                          const Handshake_State* state,
+                          Credentials_Manager& creds);
+
    private:
       MemoryVector<byte> serialize() const { return key_material; }
 
diff --git a/src/tls/tls_policy.cpp b/src/tls/tls_policy.cpp
index a547e8fd5..6718b2e1e 100644
--- a/src/tls/tls_policy.cpp
+++ b/src/tls/tls_policy.cpp
@@ -245,8 +245,11 @@ u16bit Policy::choose_suite(const std::vector<u16bit>& client_suites,
             continue;
          }
 
-      if(!value_exists(available_cert_types, suite.sig_algo()))
+      if(suite.sig_algo() != "" &&
+         !value_exists(available_cert_types, suite.sig_algo()))
+         {
          continue;
+         }
 
       if(value_exists(client_suites, suite_id))
          return suite_id;
diff --git a/src/tls/tls_server.cpp b/src/tls/tls_server.cpp
index 9002c3e05..9c4410938 100644
--- a/src/tls/tls_server.cpp
+++ b/src/tls/tls_server.cpp
@@ -308,7 +308,7 @@ void Server::process_handshake_msg(Handshake_Type type,
             {
             state->server_rsa_kex_key = private_key;
             }
-         else
+         else if(kex_algo != "PSK") // FIXME: means we never send identity hint
             {
             state->server_kex =
                new Server_Key_Exchange(writer, state, policy, rng, private_key);
@@ -358,8 +358,7 @@ void Server::process_handshake_msg(Handshake_Type type,
       else
          state->set_expected_next(HANDSHAKE_CCS);
 
-      state->client_kex = new Client_Key_Exchange(contents, state->suite,
-                                                  state->version);
+      state->client_kex = new Client_Key_Exchange(contents, state, creds);
 
       SecureVector<byte> pre_master =
          state->client_kex->pre_master_secret(rng, state);