1 files changed, 101 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/tls/tls_session_key.cpp b/comm/third_party/botan/src/lib/tls/tls_session_key.cpp
new file mode 100644
index 0000000000..2066810413
--- /dev/null
+++ b/comm/third_party/botan/src/lib/tls/tls_session_key.cpp
@@ -0,0 +1,101 @@
+/*
+* TLS Session Key
+* (C) 2004-2006,2011,2016,2019 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/internal/tls_session_key.h>
+#include <botan/internal/tls_handshake_state.h>
+#include <botan/tls_messages.h>
+#include <botan/kdf.h>
+
+namespace Botan {
+
+namespace TLS {
+
+/**
+* Session_Keys Constructor
+*/
+Session_Keys::Session_Keys(const Handshake_State* state,
+                           const secure_vector<uint8_t>& pre_master_secret,
+                           bool resuming)
+   {
+   const size_t cipher_keylen = state->ciphersuite().cipher_keylen();
+   const size_t mac_keylen = state->ciphersuite().mac_keylen();
+   const size_t cipher_nonce_bytes = state->ciphersuite().nonce_bytes_from_handshake();
+
+   const bool extended_master_secret = state->server_hello()->supports_extended_master_secret();
+
+   const size_t prf_gen = 2 * (mac_keylen + cipher_keylen + cipher_nonce_bytes);
+
+   const uint8_t MASTER_SECRET_MAGIC[] = {
+      0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x73, 0x65, 0x63, 0x72, 0x65, 0x74 };
+
+   const uint8_t EXT_MASTER_SECRET_MAGIC[] = {
+      0x65, 0x78, 0x74, 0x65, 0x6E, 0x64, 0x65, 0x64, 0x20,
+      0x6D, 0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x73, 0x65, 0x63, 0x72, 0x65, 0x74 };
+
+   const uint8_t KEY_GEN_MAGIC[] = {
+      0x6B, 0x65, 0x79, 0x20, 0x65, 0x78, 0x70, 0x61, 0x6E, 0x73, 0x69, 0x6F, 0x6E };
+
+   std::unique_ptr<KDF> prf(state->protocol_specific_prf());
+
+   if(resuming)
+      {
+      // This is actually the master secret saved as part of the session
+      m_master_sec = pre_master_secret;
+      }
+   else
+      {
+      std::vector<uint8_t> salt;
+      std::vector<uint8_t> label;
+      if(extended_master_secret)
+         {
+         label.assign(EXT_MASTER_SECRET_MAGIC, EXT_MASTER_SECRET_MAGIC + sizeof(EXT_MASTER_SECRET_MAGIC));
+         salt += state->hash().final(state->version(),
+                                     state->ciphersuite().prf_algo());
+         }
+      else
+         {
+         label.assign(MASTER_SECRET_MAGIC, MASTER_SECRET_MAGIC + sizeof(MASTER_SECRET_MAGIC));
+         salt += state->client_hello()->random();
+         salt += state->server_hello()->random();
+         }
+
+      m_master_sec = prf->derive_key(48, pre_master_secret, salt, label);
+      }
+
+   std::vector<uint8_t> salt;
+   std::vector<uint8_t> label;
+   label.assign(KEY_GEN_MAGIC, KEY_GEN_MAGIC + sizeof(KEY_GEN_MAGIC));
+   salt += state->server_hello()->random();
+   salt += state->client_hello()->random();
+
+   const secure_vector<uint8_t> prf_output = prf->derive_key(
+      prf_gen,
+      m_master_sec.data(), m_master_sec.size(),
+      salt.data(), salt.size(),
+      label.data(), label.size());
+
+   const uint8_t* key_data = prf_output.data();
+
+   m_c_aead.resize(mac_keylen + cipher_keylen);
+   m_s_aead.resize(mac_keylen + cipher_keylen);
+
+   copy_mem(&m_c_aead[0], key_data, mac_keylen);
+   copy_mem(&m_s_aead[0], key_data + mac_keylen, mac_keylen);
+
+   copy_mem(&m_c_aead[mac_keylen], key_data + 2*mac_keylen, cipher_keylen);
+   copy_mem(&m_s_aead[mac_keylen], key_data + 2*mac_keylen + cipher_keylen, cipher_keylen);
+
+   m_c_nonce.resize(cipher_nonce_bytes);
+   m_s_nonce.resize(cipher_nonce_bytes);
+
+   copy_mem(&m_c_nonce[0], key_data + 2*(mac_keylen + cipher_keylen), cipher_nonce_bytes);
+   copy_mem(&m_s_nonce[0], key_data + 2*(mac_keylen + cipher_keylen) + cipher_nonce_bytes, cipher_nonce_bytes);
+   }
+
+}
+
+}