propagate from branch 'net.randombit.botan.tls-state-machine' (head 6bcbae3d22e4d873a8e941d0325ad666482ac4da)

            to branch 'net.randombit.botan.tls-session-ticket' (head 9048722b5d18b39cf21f8542942dab94a9bd4e6b)

16 files changed, 456 insertions, 57 deletions

diff --git a/src/build-data/cc/gcc.txt b/src/build-data/cc/gcc.txt
index 3de85099c..6173f6271 100644
--- a/src/build-data/cc/gcc.txt
+++ b/src/build-data/cc/gcc.txt
@@ -13,7 +13,7 @@ add_lib_option -l
 lang_flags "-D_REENTRANT -Wno-long-long"
 warning_flags "-W -Wall"
 
-maintainer_warning_flags "-Werror -Weffc++ -Wall -Wextra -Wstrict-aliasing -Wstrict-overflow=5 -Wcast-align -Wmissing-declarations -Wpointer-arith -Wcast-qual -Wold-style-cast"
+maintainer_warning_flags "-Werror -Wall -Wextra -Wstrict-aliasing -Wstrict-overflow=5 -Wcast-align -Wmissing-declarations -Wpointer-arith -Wcast-qual -Wold-style-cast"
 
 lib_opt_flags "-O3"
 check_opt_flags "-O2"
diff --git a/src/tls/c_hello.cpp b/src/tls/c_hello.cpp
index 35389f37b..0798bfaf3 100644
--- a/src/tls/c_hello.cpp
+++ b/src/tls/c_hello.cpp
@@ -71,7 +71,8 @@ Client_Hello::Client_Hello(Record_Writer& writer,
    m_next_protocol(next_protocol),
    m_fragment_size(0),
    m_secure_renegotiation(true),
-   m_renegotiation_info(reneg_info)
+   m_renegotiation_info(reneg_info),
+   m_supports_session_ticket(true)
    {
    std::vector<std::string> hashes = policy.allowed_hashes();
    std::vector<std::string> sigs = policy.allowed_signature_methods();
@@ -86,7 +87,7 @@ Client_Hello::Client_Hello(Record_Writer& writer,
    }
 
 /*
-* Create a new Client Hello message
+* Create a new Client Hello message (session resumption case)
 */
 Client_Hello::Client_Hello(Record_Writer& writer,
                            Handshake_Hash& hash,
@@ -100,7 +101,9 @@ Client_Hello::Client_Hello(Record_Writer& writer,
    m_srp_identifier(session.srp_identifier()),
    m_next_protocol(next_protocol),
    m_fragment_size(session.fragment_size()),
-   m_secure_renegotiation(session.secure_renegotiation())
+   m_secure_renegotiation(session.secure_renegotiation()),
+   m_supports_session_ticket(true),
+   m_session_ticket(session.session_ticket())
    {
    m_suites.push_back(session.ciphersuite_code());
    m_comp_methods.push_back(session.compression_method());
@@ -110,10 +113,14 @@ Client_Hello::Client_Hello(Record_Writer& writer,
    hash.update(writer.send(*this));
    }
 
+/*
+* Read a counterparty client hello
+*/
 Client_Hello::Client_Hello(const MemoryRegion<byte>& buf, Handshake_Type type)
    {
    m_next_protocol = false;
    m_secure_renegotiation = false;
+   m_supports_session_ticket = false;
    m_fragment_size = 0;
 
    if(type == CLIENT_HELLO)
@@ -159,11 +166,14 @@ MemoryVector<byte> Client_Hello::serialize() const
 
       if(m_next_protocol)
          extensions.add(new Next_Protocol_Notification());
+
+      extensions.add(new Session_Ticket(m_session_ticket));
       }
    else
       {
       // renegotiation
       extensions.add(new Renegotation_Extension(m_renegotiation_info));
+      extensions.add(new Session_Ticket(m_session_ticket));
       }
 
    buf += extensions.serialize();
@@ -302,6 +312,24 @@ void Client_Hello::deserialize(const MemoryRegion<byte>& buf)
          }
       }
 
+   if(Maximum_Fragment_Length* frag = extensions.get<Maximum_Fragment_Length>())
+      {
+      m_fragment_size = frag->fragment_size();
+      }
+
+   if(Session_Ticket* ticket = extensions.get<Session_Ticket>())
+      {
+      m_supports_session_ticket = true;
+      m_session_ticket = ticket->contents();
+      }
+
+   if(Renegotation_Extension* reneg = extensions.get<Renegotation_Extension>())
+      {
+      // checked by TLS_Client / TLS_Server as they know the handshake state
+      m_secure_renegotiation = true;
+      m_renegotiation_info = reneg->renegotiation_info();
+      }
+
    if(value_exists(m_suites, static_cast<u16bit>(TLS_EMPTY_RENEGOTIATION_INFO_SCSV)))
       {
       /*
diff --git a/src/tls/info.txt b/src/tls/info.txt
index 822914a3d..9cc936471 100644
--- a/src/tls/info.txt
+++ b/src/tls/info.txt
@@ -45,6 +45,7 @@ rec_read.cpp
 rec_wri.cpp
 s_hello.cpp
 s_kex.cpp
+session_ticket.cpp
 tls_channel.cpp
 tls_client.cpp
 tls_extensions.cpp
diff --git a/src/tls/s_hello.cpp b/src/tls/s_hello.cpp
index 9bcbdb5e9..4cbc69f30 100644
--- a/src/tls/s_hello.cpp
+++ b/src/tls/s_hello.cpp
@@ -37,7 +37,8 @@ Server_Hello::Server_Hello(Record_Writer& writer,
    m_secure_renegotiation(client_has_secure_renegotiation),
    m_renegotiation_info(reneg_info),
    m_next_protocol(client_has_npn),
-   m_next_protocols(next_protocols)
+   m_next_protocols(next_protocols),
+   m_supports_session_ticket(c_hello.supports_session_ticket())
    {
    suite = policy.choose_suite(
       c_hello.ciphersuites(),
@@ -66,6 +67,7 @@ Server_Hello::Server_Hello(Record_Writer& writer,
                            size_t max_fragment_size,
                            bool client_has_secure_renegotiation,
                            const MemoryRegion<byte>& reneg_info,
+                           bool client_supports_session_tickets,
                            bool client_has_npn,
                            const std::vector<std::string>& next_protocols,
                            RandomNumberGenerator& rng) :
@@ -78,7 +80,8 @@ Server_Hello::Server_Hello(Record_Writer& writer,
    m_secure_renegotiation(client_has_secure_renegotiation),
    m_renegotiation_info(reneg_info),
    m_next_protocol(client_has_npn),
-   m_next_protocols(next_protocols)
+   m_next_protocols(next_protocols),
+   m_supports_session_ticket(client_supports_session_tickets)
    {
    hash.update(writer.send(*this));
    }
@@ -89,6 +92,7 @@ Server_Hello::Server_Hello(Record_Writer& writer,
 Server_Hello::Server_Hello(const MemoryRegion<byte>& buf)
    {
    m_secure_renegotiation = false;
+   m_supports_session_ticket = false;
    m_next_protocol = false;
 
    if(buf.size() < 38)
@@ -132,6 +136,13 @@ Server_Hello::Server_Hello(const MemoryRegion<byte>& buf)
       m_next_protocols = npn->protocols();
       m_next_protocol = true;
       }
+
+   if(Session_Ticket* ticket = extensions.get<Session_Ticket>())
+      {
+      if(!ticket->contents().empty())
+         throw Decoding_Error("TLS server sent non-empty session ticket extension");
+      m_supports_session_ticket = true;
+      }
    }
 
 /*
@@ -163,6 +174,9 @@ MemoryVector<byte> Server_Hello::serialize() const
    if(m_next_protocol)
       extensions.add(new Next_Protocol_Notification(m_next_protocols));
 
+   if(m_supports_session_ticket)
+      extensions.add(new Session_Ticket());
+
    buf += extensions.serialize();
 
    return buf;
diff --git a/src/tls/session_ticket.cpp b/src/tls/session_ticket.cpp
new file mode 100644
index 000000000..47a8a5c32
--- /dev/null
+++ b/src/tls/session_ticket.cpp
@@ -0,0 +1,57 @@
+/*
+* Session Tickets
+* (C) 2012 Jack Lloyd
+*
+* Released under the terms of the Botan license
+*/
+
+#include <botan/internal/tls_messages.h>
+#include <botan/internal/tls_extensions.h>
+#include <botan/internal/tls_reader.h>
+#include <botan/tls_record.h>
+#include <botan/loadstor.h>
+
+namespace Botan {
+
+namespace TLS {
+
+New_Session_Ticket::New_Session_Ticket(Record_Writer& writer,
+                                       Handshake_Hash& hash,
+                                       const MemoryRegion<byte>& ticket,
+                                       u32bit lifetime) :
+   m_ticket_lifetime_hint(lifetime),
+   m_ticket(ticket)
+   {
+   hash.update(writer.send(*this));
+   }
+
+New_Session_Ticket::New_Session_Ticket(Record_Writer& writer,
+                                       Handshake_Hash& hash) :
+   m_ticket_lifetime_hint(0)
+   {
+   hash.update(writer.send(*this));
+   }
+
+New_Session_Ticket::New_Session_Ticket(const MemoryRegion<byte>& buf) :
+   m_ticket_lifetime_hint(0)
+   {
+   if(buf.size() >= 6)
+      {
+      TLS_Data_Reader reader(buf);
+
+      m_ticket_lifetime_hint = reader.get_u32bit();
+      m_ticket = reader.get_range<byte>(2, 0, 65535);
+      }
+   }
+
+MemoryVector<byte> New_Session_Ticket::serialize() const
+   {
+   MemoryVector<byte> buf(4);
+   store_be(m_ticket_lifetime_hint, &buf[0]);
+   append_tls_length_value(buf, m_ticket, 2);
+   return buf;
+   }
+
+}
+
+}
diff --git a/src/tls/sessions_sqlite/tls_sqlite_sess_mgr.cpp b/src/tls/sessions_sqlite/tls_sqlite_sess_mgr.cpp
index b02dc95f6..3fea68a74 100644
--- a/src/tls/sessions_sqlite/tls_sqlite_sess_mgr.cpp
+++ b/src/tls/sessions_sqlite/tls_sqlite_sess_mgr.cpp
@@ -209,7 +209,8 @@ void Session_Manager_SQLite::remove_entry(const MemoryRegion<byte>& session_id)
 
 void Session_Manager_SQLite::save(const Session& session)
    {
-   sqlite3_statement stmt(m_db, "insert into " + m_table_name + " values(?1, ?2, ?3, ?4, ?5)");
+   sqlite3_statement stmt(m_db, "insert or replace into " + m_table_name +
+                                " values(?1, ?2, ?3, ?4, ?5)");
 
    stmt.bind(1, hex_encode(session.session_id()));
    stmt.bind(2, session.start_time());
diff --git a/src/tls/tls_client.cpp b/src/tls/tls_client.cpp
index 02e24a1c9..06a58385c 100644
--- a/src/tls/tls_client.cpp
+++ b/src/tls/tls_client.cpp
@@ -112,7 +112,7 @@ void Client::alert_notify(const Alert& alert)
 * Process a handshake message
 */
 void Client::process_handshake_msg(Handshake_Type type,
-                                       const MemoryRegion<byte>& contents)
+                                   const MemoryRegion<byte>& contents)
    {
    if(state == 0)
       throw Unexpected_Message("Unexpected handshake message from server");
@@ -135,12 +135,12 @@ void Client::process_handshake_msg(Handshake_Type type,
          return;
          }
 
-      state->set_expected_next(SERVER_HELLO);
       state->client_hello = new Client_Hello(writer, state->hash, policy, rng,
                                              secure_renegotiation.for_client_hello());
-
       secure_renegotiation.update(state->client_hello);
 
+      state->set_expected_next(SERVER_HELLO);
+
       return;
       }
 
@@ -173,6 +173,13 @@ void Client::process_handshake_msg(Handshake_Type type,
                              "Server sent next protocol but we didn't request it");
          }
 
+      if(state->server_hello->supports_session_ticket())
+         {
+         if(!state->client_hello->supports_session_ticket())
+            throw TLS_Exception(Alert::HANDSHAKE_FAILURE,
+                                "Server sent session ticket extension but we did not");
+         }
+
       state->set_version(state->server_hello->version());
 
       writer.set_version(state->version());
@@ -182,8 +189,11 @@ void Client::process_handshake_msg(Handshake_Type type,
 
       state->suite = Ciphersuite::by_id(state->server_hello->ciphersuite());
 
-      if(!state->server_hello->session_id().empty() &&
-         (state->server_hello->session_id() == state->client_hello->session_id()))
+      const bool server_returned_same_session_id =
+         !state->server_hello->session_id().empty() &&
+         (state->server_hello->session_id() == state->client_hello->session_id());
+
+      if(server_returned_same_session_id)
          {
          // successful resumption
 
@@ -199,7 +209,10 @@ void Client::process_handshake_msg(Handshake_Type type,
                                     state->resume_master_secret,
                                     true);
 
-         state->set_expected_next(HANDSHAKE_CCS);
+         if(state->server_hello->supports_session_ticket())
+            state->set_expected_next(NEW_SESSION_TICKET);
+         else
+            state->set_expected_next(HANDSHAKE_CCS);
          }
       else
          {
@@ -306,8 +319,6 @@ void Client::process_handshake_msg(Handshake_Type type,
       }
    else if(type == SERVER_HELLO_DONE)
       {
-      state->set_expected_next(HANDSHAKE_CCS);
-
       state->server_hello_done = new Server_Hello_Done(contents);
 
       if(state->received_handshake_msg(CERTIFICATE_REQUEST))
@@ -364,6 +375,17 @@ void Client::process_handshake_msg(Handshake_Type type,
          }
 
       state->client_finished = new Finished(writer, state, CLIENT);
+
+      if(state->server_hello->supports_session_ticket())
+         state->set_expected_next(NEW_SESSION_TICKET);
+      else
+         state->set_expected_next(HANDSHAKE_CCS);
+      }
+   else if(type == NEW_SESSION_TICKET)
+      {
+      state->new_session_ticket = new New_Session_Ticket(contents);
+
+      state->set_expected_next(HANDSHAKE_CCS);
       }
    else if(type == HANDSHAKE_CCS)
       {
@@ -394,8 +416,17 @@ void Client::process_handshake_msg(Handshake_Type type,
          state->client_finished = new Finished(writer, state, CLIENT);
          }
 
+      secure_renegotiation.update(state->client_finished, state->server_finished);
+
+      MemoryVector<byte> session_id = state->server_hello->session_id();
+
+      const MemoryRegion<byte>& session_ticket = state->session_ticket();
+
+      if(session_id.empty() && !session_ticket.empty())
+         session_id = make_hello_random(rng);
+
       Session session_info(
-         state->server_hello->session_id(),
+         session_id,
          state->keys.master_secret(),
          state->server_hello->version(),
          state->server_hello->ciphersuite(),
@@ -404,6 +435,7 @@ void Client::process_handshake_msg(Handshake_Type type,
          secure_renegotiation.supported(),
          state->server_hello->fragment_size(),
          peer_certs,
+         session_ticket,
          state->client_hello->sni_hostname(),
          ""
          );
@@ -413,8 +445,6 @@ void Client::process_handshake_msg(Handshake_Type type,
       else
          session_manager.remove_entry(session_info.session_id());
 
-      secure_renegotiation.update(state->client_finished, state->server_finished);
-
       delete state;
       state = 0;
       handshake_completed = true;
diff --git a/src/tls/tls_extensions.cpp b/src/tls/tls_extensions.cpp
index 5d345cc9b..1ca4e3eb4 100644
--- a/src/tls/tls_extensions.cpp
+++ b/src/tls/tls_extensions.cpp
@@ -42,6 +42,9 @@ Extension* make_extension(TLS_Data_Reader& reader,
       case TLSEXT_NEXT_PROTOCOL:
          return new Next_Protocol_Notification(reader, size);
 
+      case TLSEXT_SESSION_TICKET:
+         return new Session_Ticket(reader, size);
+
       default:
          return 0; // not known
       }
@@ -501,6 +504,12 @@ Signature_Algorithms::Signature_Algorithms(TLS_Data_Reader& reader,
       }
    }
 
+Session_Ticket::Session_Ticket(TLS_Data_Reader& reader,
+                               u16bit extension_size)
+   {
+   m_ticket = reader.get_elem<byte, MemoryVector<byte> >(extension_size);
+   }
+
 }
 
 }
diff --git a/src/tls/tls_extensions.h b/src/tls/tls_extensions.h
index 180216b8b..6a97d2560 100644
--- a/src/tls/tls_extensions.h
+++ b/src/tls/tls_extensions.h
@@ -1,6 +1,6 @@
 /*
 * TLS Extensions
-* (C) 2011 Jack Lloyd
+* (C) 2011-2012 Jack Lloyd
 *
 * Released under the terms of the Botan license
 */
@@ -210,6 +210,39 @@ class Next_Protocol_Notification : public Extension
       std::vector<std::string> m_protocols;
    };
 
+class Session_Ticket : public Extension
+   {
+   public:
+      static Handshake_Extension_Type static_type()
+         { return TLSEXT_SESSION_TICKET; }
+
+      Handshake_Extension_Type type() const { return static_type(); }
+
+      const MemoryVector<byte>& contents() const { return m_ticket; }
+
+      /**
+      * Create empty extension, used by both client and server
+      */
+      Session_Ticket() {}
+
+      /**
+      * Extension with ticket, used by client
+      */
+      Session_Ticket(const MemoryRegion<byte>& session_ticket) :
+         m_ticket(session_ticket) {}
+
+      /**
+      * Deserialize a session ticket
+      */
+      Session_Ticket(TLS_Data_Reader& reader, u16bit extension_size);
+
+      MemoryVector<byte> serialize() const { return m_ticket; }
+
+      bool empty() const { return false; }
+   private:
+      MemoryVector<byte> m_ticket;
+   };
+
 /**
 * Supported Elliptic Curves Extension (RFC 4492)
 */
diff --git a/src/tls/tls_handshake_state.cpp b/src/tls/tls_handshake_state.cpp
index 2db97db0a..6ddd8d346 100644
--- a/src/tls/tls_handshake_state.cpp
+++ b/src/tls/tls_handshake_state.cpp
@@ -54,12 +54,15 @@ u32bit bitmask_for_handshake_type(Handshake_Type type)
       case NEXT_PROTOCOL:
          return (1 << 9);
 
-      case HANDSHAKE_CCS:
+      case NEW_SESSION_TICKET:
          return (1 << 10);
 
-      case FINISHED:
+      case HANDSHAKE_CCS:
          return (1 << 11);
 
+      case FINISHED:
+         return (1 << 12);
+
       // allow explicitly disabling new handshakes
       case HANDSHAKE_NONE:
          return 0;
@@ -85,6 +88,7 @@ Handshake_State::Handshake_State(Handshake_Reader* reader)
    cert_req = 0;
    server_hello_done = 0;
    next_protocol = 0;
+   new_session_ticket = 0;
 
    client_certs = 0;
    client_kex = 0;
@@ -139,6 +143,14 @@ bool Handshake_State::received_handshake_msg(Handshake_Type handshake_msg) const
    return (hand_received_mask & mask);
    }
 
+const MemoryRegion<byte>& Handshake_State::session_ticket() const
+   {
+   if(new_session_ticket && !new_session_ticket->ticket().empty())
+      return new_session_ticket->ticket();
+
+   return client_hello->session_ticket();
+   }
+
 KDF* Handshake_State::protocol_specific_prf()
    {
    if(version() == Protocol_Version::SSL_V3)
@@ -287,6 +299,7 @@ Handshake_State::~Handshake_State()
    delete cert_req;
    delete server_hello_done;
    delete next_protocol;
+   delete new_session_ticket;
 
    delete client_certs;
    delete client_kex;
diff --git a/src/tls/tls_handshake_state.h b/src/tls/tls_handshake_state.h
index 206e19096..2a78d1d1e 100644
--- a/src/tls/tls_handshake_state.h
+++ b/src/tls/tls_handshake_state.h
@@ -50,6 +50,8 @@ class Handshake_State
       void confirm_transition_to(Handshake_Type handshake_msg);
       void set_expected_next(Handshake_Type handshake_msg);
 
+      const MemoryRegion<byte>& session_ticket() const;
+
       std::pair<std::string, Signature_Format>
          understand_sig_format(const Public_Key* key,
                                std::string hash_algo,
@@ -80,6 +82,7 @@ class Handshake_State
       class Certificate_Verify* client_verify;
 
       class Next_Protocol* next_protocol;
+      class New_Session_Ticket* new_session_ticket;
 
       class Finished* client_finished;
       class Finished* server_finished;
diff --git a/src/tls/tls_messages.h b/src/tls/tls_messages.h
index 513fdad70..78cb6f714 100644
--- a/src/tls/tls_messages.h
+++ b/src/tls/tls_messages.h
@@ -108,6 +108,11 @@ class Client_Hello : public Handshake_Message
 
       size_t fragment_size() const { return m_fragment_size; }
 
+      bool supports_session_ticket() const { return m_supports_session_ticket; }
+
+      const MemoryRegion<byte>& session_ticket() const
+         { return m_session_ticket; }
+
       Client_Hello(Record_Writer& writer,
                    Handshake_Hash& hash,
                    const Policy& policy,
@@ -145,6 +150,9 @@ class Client_Hello : public Handshake_Message
 
       std::vector<std::pair<std::string, std::string> > m_supported_algos;
       std::vector<std::string> m_supported_curves;
+
+      bool m_supports_session_ticket;
+      MemoryVector<byte> m_session_ticket;
    };
 
 /**
@@ -170,6 +178,8 @@ class Server_Hello : public Handshake_Message
 
       bool next_protocol_notification() const { return m_next_protocol; }
 
+      bool supports_session_ticket() const { return m_supports_session_ticket; }
+
       const std::vector<std::string>& next_protocols() const
          { return m_next_protocols; }
 
@@ -201,6 +211,7 @@ class Server_Hello : public Handshake_Message
                    size_t max_fragment_size,
                    bool client_has_secure_renegotiation,
                    const MemoryRegion<byte>& reneg_info,
+                   bool client_supports_session_tickets,
                    bool client_has_npn,
                    const std::vector<std::string>& next_protocols,
                    RandomNumberGenerator& rng);
@@ -220,6 +231,7 @@ class Server_Hello : public Handshake_Message
 
       bool m_next_protocol;
       std::vector<std::string> m_next_protocols;
+      bool m_supports_session_ticket;
    };
 
 /**
@@ -454,6 +466,30 @@ class Next_Protocol : public Handshake_Message
       std::string m_protocol;
    };
 
+class New_Session_Ticket : public Handshake_Message
+   {
+   public:
+      Handshake_Type type() const { return NEW_SESSION_TICKET; }
+
+      u32bit ticket_lifetime_hint() const { return m_ticket_lifetime_hint; }
+      const MemoryVector<byte>& ticket() const { return m_ticket; }
+
+      New_Session_Ticket(Record_Writer& writer,
+                         Handshake_Hash& hash,
+                         const MemoryRegion<byte>& ticket,
+                         u32bit lifetime = 0);
+
+      New_Session_Ticket(Record_Writer& writer,
+                         Handshake_Hash& hash);
+
+      New_Session_Ticket(const MemoryRegion<byte>& buf);
+   private:
+      MemoryVector<byte> serialize() const;
+
+      u32bit m_ticket_lifetime_hint;
+      MemoryVector<byte> m_ticket;
+   };
+
 }
 
 }
diff --git a/src/tls/tls_reader.h b/src/tls/tls_reader.h
index 162f691aa..f6b0d4088 100644
--- a/src/tls/tls_reader.h
+++ b/src/tls/tls_reader.h
@@ -50,6 +50,15 @@ class TLS_Data_Reader
          offset += bytes;
          }
 
+      u16bit get_u32bit()
+         {
+         assert_at_least(4);
+         u16bit result = make_u32bit(buf[offset  ], buf[offset+1],
+                                     buf[offset+2], buf[offset+3]);
+         offset += 4;
+         return result;
+         }
+
       u16bit get_u16bit()
          {
          assert_at_least(2);
diff --git a/src/tls/tls_server.cpp b/src/tls/tls_server.cpp
index eacbc02e0..7632dfcdd 100644
--- a/src/tls/tls_server.cpp
+++ b/src/tls/tls_server.cpp
@@ -22,14 +22,31 @@ bool check_for_resume(Session& session_info,
                       Session_Manager& session_manager,
                       Client_Hello* client_hello)
    {
-   MemoryVector<byte> client_session_id = client_hello->session_id();
+   const MemoryVector<byte>& client_session_id = client_hello->session_id();
+   const MemoryVector<byte>& session_ticket = client_hello->session_ticket();
 
-   if(client_session_id.empty()) // not resuming
-      return false;
+   if(session_ticket.empty())
+      {
+      if(client_session_id.empty()) // not resuming
+         return false;
 
-   // not found
-   if(!session_manager.load_from_session_id(client_session_id, session_info))
-      return false;
+      // not found
+      if(!session_manager.load_from_session_id(client_session_id, session_info))
+         return false;
+      }
+   else
+      {
+      // If a session ticket was sent, ignore client session ID
+      try
+         {
+#warning fixed key
+         session_info = Session::decrypt(session_ticket, SymmetricKey("ABCDEF"));
+         }
+      catch(std::exception& e)
+         {
+         return false;
+         }
+      }
 
    // wrong version
    if(client_hello->version() != session_info.version())
@@ -45,14 +62,14 @@ bool check_for_resume(Session& session_info,
                     session_info.compression_method()))
       return false;
 
-   // client sent a different SRP identity (!!!)
+   // client sent a different SRP identity
    if(client_hello->srp_identifier() != "")
       {
       if(client_hello->srp_identifier() != session_info.srp_identifier())
          return false;
       }
 
-   // client sent a different SNI hostname (!!!)
+   // client sent a different SNI hostname
    if(client_hello->sni_hostname() != "")
       {
       if(client_hello->sni_hostname() != session_info.sni_hostname())
@@ -204,13 +221,14 @@ void Server::process_handshake_msg(Handshake_Type type,
          state->server_hello = new Server_Hello(
             writer,
             state->hash,
-            session_info.session_id(),
+            state->client_hello->session_id(),
             Protocol_Version(session_info.version()),
             session_info.ciphersuite_code(),
             session_info.compression_method(),
             session_info.fragment_size(),
             secure_renegotiation.supported(),
             secure_renegotiation.for_server_hello(),
+            state->client_hello->supports_session_ticket(),
             state->client_hello->next_protocol_notification(),
             m_possible_protocols,
             rng);
@@ -225,6 +243,22 @@ void Server::process_handshake_msg(Handshake_Type type,
 
          state->keys = Session_Keys(state, session_info.master_secret(), true);
 
+         if(!handshake_fn(session_info))
+            {
+            if(state->server_hello->supports_session_ticket())
+               state->new_session_ticket = new New_Session_Ticket(writer, state->hash);
+            else
+               session_manager.remove_entry(session_info.session_id());
+            }
+
+         // Should only send a new ticket if we need too (eg old session)
+         if(state->server_hello->supports_session_ticket() && !state->new_session_ticket)
+            {
+            state->new_session_ticket =
+               new New_Session_Ticket(writer, state->hash,
+                                      session_info.encrypt(SymmetricKey("ABCDEF"), rng));
+            }
+
          writer.send(CHANGE_CIPHER_SPEC, 1);
 
          writer.activate(SERVER, state->suite, state->keys,
@@ -232,8 +266,6 @@ void Server::process_handshake_msg(Handshake_Type type,
 
          state->server_finished = new Finished(writer, state, SERVER);
 
-         if(!handshake_fn(session_info))
-            session_manager.remove_entry(session_info.session_id());
 
          state->set_expected_next(HANDSHAKE_CCS);
          }
@@ -423,20 +455,10 @@ void Server::process_handshake_msg(Handshake_Type type,
 
       if(!state->server_finished)
          {
-         state->hash.update(type, contents);
-
-         writer.send(CHANGE_CIPHER_SPEC, 1);
-
-         writer.activate(SERVER, state->suite, state->keys,
-                         state->server_hello->compression_method());
-
-         state->server_finished = new Finished(writer, state, SERVER);
-
-         if(state->client_certs && state->client_verify)
-            peer_certs = state->client_certs->cert_chain();
-
          // already sent finished if resuming, so this is a new session
 
+         state->hash.update(type, contents);
+
          Session session_info(
             state->server_hello->session_id(),
             state->keys.master_secret(),
@@ -447,12 +469,35 @@ void Server::process_handshake_msg(Handshake_Type type,
             secure_renegotiation.supported(),
             state->server_hello->fragment_size(),
             peer_certs,
+            MemoryVector<byte>(),
             m_hostname,
             ""
             );
 
          if(handshake_fn(session_info))
-            session_manager.save(session_info);
+            {
+            if(state->server_hello->supports_session_ticket())
+               {
+               state->new_session_ticket =
+                  new New_Session_Ticket(writer, state->hash,
+                                         session_info.encrypt(SymmetricKey("ABCDEF"), rng));
+               }
+            else
+               session_manager.save(session_info);
+            }
+
+         if(state->server_hello->supports_session_ticket() && !state->new_session_ticket)
+            state->new_session_ticket = new New_Session_Ticket(writer, state->hash);
+
+         writer.send(CHANGE_CIPHER_SPEC, 1);
+
+         writer.activate(SERVER, state->suite, state->keys,
+                         state->server_hello->compression_method());
+
+         state->server_finished = new Finished(writer, state, SERVER);
+
+         if(state->client_certs && state->client_verify)
+            peer_certs = state->client_certs->cert_chain();
          }
 
       secure_renegotiation.update(state->client_finished,
diff --git a/src/tls/tls_session.cpp b/src/tls/tls_session.cpp
index 7a32c33d8..a41112bf4 100644
--- a/src/tls/tls_session.cpp
+++ b/src/tls/tls_session.cpp
@@ -1,6 +1,6 @@
 /*
 * TLS Session State
-* (C) 2011 Jack Lloyd
+* (C) 2011-2012 Jack Lloyd
 *
 * Released under the terms of the Botan license
 */
@@ -11,6 +11,9 @@
 #include <botan/asn1_str.h>
 #include <botan/pem.h>
 #include <botan/time.h>
+#include <botan/lookup.h>
+#include <botan/loadstor.h>
+#include <memory>
 
 namespace Botan {
 
@@ -25,10 +28,12 @@ Session::Session(const MemoryRegion<byte>& session_identifier,
                  bool secure_renegotiation_supported,
                  size_t fragment_size,
                  const std::vector<X509_Certificate>& certs,
+                 const MemoryRegion<byte>& ticket,
                  const std::string& sni_hostname,
                  const std::string& srp_identifier) :
    m_start_time(system_time()),
    m_identifier(session_identifier),
+   m_session_ticket(ticket),
    m_master_secret(master_secret),
    m_version(version),
    m_ciphersuite(ciphersuite),
@@ -42,6 +47,13 @@ Session::Session(const MemoryRegion<byte>& session_identifier,
    {
    }
 
+Session::Session(const std::string& pem)
+   {
+   SecureVector<byte> der = PEM_Code::decode_check_label(pem, "SSL SESSION");
+
+   *this = Session(&der[0], der.size());
+   }
+
 Session::Session(const byte ber[], size_t ber_len)
    {
    byte side_code = 0;
@@ -56,10 +68,11 @@ Session::Session(const byte ber[], size_t ber_len)
       .start_cons(SEQUENCE)
         .decode_and_check(static_cast<size_t>(TLS_SESSION_PARAM_STRUCT_VERSION),
                           "Unknown version in session structure")
-        .decode(m_identifier, OCTET_STRING)
         .decode_integer_type(m_start_time)
         .decode_integer_type(major_version)
         .decode_integer_type(minor_version)
+        .decode(m_identifier, OCTET_STRING)
+        .decode(m_session_ticket, OCTET_STRING)
         .decode_integer_type(m_ciphersuite)
         .decode_integer_type(m_compression_method)
         .decode_integer_type(side_code)
@@ -86,13 +99,6 @@ Session::Session(const byte ber[], size_t ber_len)
       }
    }
 
-Session::Session(const std::string& pem)
-   {
-   SecureVector<byte> der = PEM_Code::decode_check_label(pem, "SSL SESSION");
-
-   *this = Session(&der[0], der.size());
-   }
-
 SecureVector<byte> Session::DER_encode() const
    {
    MemoryVector<byte> peer_cert_bits;
@@ -102,10 +108,11 @@ SecureVector<byte> Session::DER_encode() const
    return DER_Encoder()
       .start_cons(SEQUENCE)
          .encode(static_cast<size_t>(TLS_SESSION_PARAM_STRUCT_VERSION))
-         .encode(m_identifier, OCTET_STRING)
          .encode(static_cast<size_t>(m_start_time))
          .encode(static_cast<size_t>(m_version.major_version()))
          .encode(static_cast<size_t>(m_version.minor_version()))
+         .encode(m_identifier, OCTET_STRING)
+         .encode(m_session_ticket, OCTET_STRING)
          .encode(static_cast<size_t>(m_ciphersuite))
          .encode(static_cast<size_t>(m_compression_method))
          .encode(static_cast<size_t>(m_connection_side))
@@ -124,6 +131,97 @@ std::string Session::PEM_encode() const
    return PEM_Code::encode(this->DER_encode(), "SSL SESSION");
    }
 
+namespace {
+
+const u64bit ENCRYPTED_SESSION_MAGIC = 0xACE4480800000000;
+
+}
+
+MemoryVector<byte>
+Session::encrypt(const SymmetricKey& master_key,
+                 RandomNumberGenerator& rng)
+   {
+   std::auto_ptr<KDF> kdf(get_kdf("KDF2(SHA-256)"));
+
+   SymmetricKey aes_key = kdf->derive_key(32, master_key.bits_of(),
+                                          "tls.session.cipher-key");
+
+   SymmetricKey hmac_key = kdf->derive_key(32, master_key.bits_of(),
+                                           "tls.session.mac-key");
+
+   InitializationVector aes_iv(rng, 16);
+
+   std::auto_ptr<MessageAuthenticationCode> mac(get_mac("HMAC(SHA-256)"));
+   mac->set_key(hmac_key);
+
+   Pipe pipe(get_cipher("AES-256/CBC", aes_key, aes_iv, ENCRYPTION));
+   pipe.process_msg(this->DER_encode());
+   MemoryVector<byte> ctext = pipe.read_all(0);
+
+   MemoryVector<byte> out(8);
+   store_be(ENCRYPTED_SESSION_MAGIC, &out[0]);
+   out += aes_iv.bits_of();
+   out += ctext;
+
+   mac->update(out);
+
+   out += mac->final();
+   return out;
+   }
+
+Session Session::decrypt(const MemoryRegion<byte>& buf,
+                         const SymmetricKey& master_key)
+   {
+   try
+      {
+      /*
+      8 bytes header
+      16 bytes IV
+      32 bytes MAC
+      16 bytes per AES block * 4 blocks (absolute min amount due to
+        48 bytes master secret)
+      */
+      if(buf.size() < (8 + 16 + 32 + 4*16))
+         throw Decoding_Error("Encrypted TLS session too short to be valid");
+
+      std::auto_ptr<KDF> kdf(get_kdf("KDF2(SHA-256)"));
+
+      SymmetricKey hmac_key = kdf->derive_key(32, master_key.bits_of(),
+                                              "tls.session.mac-key");
+
+      std::auto_ptr<MessageAuthenticationCode> mac(get_mac("HMAC(SHA-256)"));
+      mac->set_key(hmac_key);
+
+      mac->update(&buf[0], buf.size() - 32);
+      MemoryVector<byte> computed_mac = mac->final();
+
+      if(!same_mem(&buf[buf.size() - 32], &computed_mac[0], computed_mac.size()))
+         throw Decoding_Error("MAC verification failed for encrypted session");
+
+      const u64bit header = load_be<u64bit>(buf, 0);
+
+      if(header != ENCRYPTED_SESSION_MAGIC)
+         throw Decoding_Error("Unknown header value in encrypted session");
+
+      SymmetricKey aes_key = kdf->derive_key(32, master_key.bits_of(),
+                                             "tls.session.cipher-key");
+
+      InitializationVector aes_iv(&buf[8], 16);
+
+      Pipe pipe(get_cipher("AES-256/CBC", aes_key, aes_iv, DECRYPTION));
+      pipe.process_msg(&buf[8+16], buf.size() - (32 + 8 + 16));
+      SecureVector<byte> ber = pipe.read_all();
+
+      return Session(&ber[0], ber.size());
+      }
+   catch(std::exception& e)
+      {
+      throw Decoding_Error("Failed to decrypt encrypted session -" +
+                           std::string(e.what()));
+      }
+   }
+
 }
 
 }
+
diff --git a/src/tls/tls_session.h b/src/tls/tls_session.h
index 96b6d6daf..ab11154c9 100644
--- a/src/tls/tls_session.h
+++ b/src/tls/tls_session.h
@@ -1,6 +1,6 @@
 /*
 * TLS Session
-* (C) 2011 Jack Lloyd
+* (C) 2011-2012 Jack Lloyd
 *
 * Released under the terms of the Botan license
 */
@@ -13,6 +13,7 @@
 #include <botan/tls_ciphersuite.h>
 #include <botan/tls_magic.h>
 #include <botan/secmem.h>
+#include <botan/symkey.h>
 
 namespace Botan {
 
@@ -50,6 +51,7 @@ class BOTAN_DLL Session
               bool secure_renegotiation_supported,
               size_t fragment_size,
               const std::vector<X509_Certificate>& peer_certs,
+              const MemoryRegion<byte>& session_ticket,
               const std::string& sni_hostname = "",
               const std::string& srp_identifier = "");
 
@@ -71,6 +73,20 @@ class BOTAN_DLL Session
       SecureVector<byte> DER_encode() const;
 
       /**
+      * Encrypt a session (useful for serialization or session tickets)
+      */
+      MemoryVector<byte> encrypt(const SymmetricKey& key,
+                                 RandomNumberGenerator& rng);
+
+      /**
+      * Decrypt a session created by encrypt
+      * @param ctext the ciphertext returned by encrypt
+      * @param key the same key used by the encrypting side
+      */
+      static Session decrypt(const MemoryRegion<byte>& ctext,
+                             const SymmetricKey& key);
+
+      /**
       * Encode this session data for storage
       * @warning if the master secret is compromised so is the
       * session traffic
@@ -146,12 +162,18 @@ class BOTAN_DLL Session
       */
       u64bit start_time() const { return m_start_time; }
 
+      /**
+      * Return the session ticket the server gave us
+      */
+      const MemoryVector<byte>& session_ticket() const { return m_session_ticket; }
+
    private:
-      enum { TLS_SESSION_PARAM_STRUCT_VERSION = 1 };
+      enum { TLS_SESSION_PARAM_STRUCT_VERSION = 0x2994e300 };
 
       u64bit m_start_time;
 
       MemoryVector<byte> m_identifier;
+      MemoryVector<byte> m_session_ticket; // only used by client side
       SecureVector<byte> m_master_secret;
 
       Protocol_Version m_version;