1 files changed, 117 insertions, 0 deletions
diff --git a/src/lib/kdf/prf_tls/prf_tls.cpp b/src/lib/kdf/prf_tls/prf_tls.cpp
new file mode 100644
index 000000000..006b418c9
--- /dev/null
+++ b/src/lib/kdf/prf_tls/prf_tls.cpp
@@ -0,0 +1,117 @@
+/*
+* TLS v1.0 and v1.2 PRFs
+* (C) 2004-2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/prf_tls.h>
+#include <botan/internal/xor_buf.h>
+#include <botan/hmac.h>
+#include <botan/md5.h>
+#include <botan/sha160.h>
+
+namespace Botan {
+
+namespace {
+
+/*
+* TLS PRF P_hash function
+*/
+void P_hash(secure_vector<byte>& output,
+            MessageAuthenticationCode* mac,
+            const byte secret[], size_t secret_len,
+            const byte seed[], size_t seed_len)
+   {
+   try
+      {
+      mac->set_key(secret, secret_len);
+      }
+   catch(Invalid_Key_Length)
+      {
+      throw Internal_Error("The premaster secret of " +
+                           std::to_string(secret_len) +
+                           " bytes is too long for the PRF");
+      }
+
+   secure_vector<byte> A(seed, seed + seed_len);
+
+   size_t offset = 0;
+
+   while(offset != output.size())
+      {
+      const size_t this_block_len =
+         std::min<size_t>(mac->output_length(), output.size() - offset);
+
+      A = mac->process(A);
+
+      mac->update(A);
+      mac->update(seed, seed_len);
+      secure_vector<byte> block = mac->final();
+
+      xor_buf(&output[offset], &block[0], this_block_len);
+      offset += this_block_len;
+      }
+   }
+
+}
+
+/*
+* TLS PRF Constructor and Destructor
+*/
+TLS_PRF::TLS_PRF()
+   {
+   hmac_md5 = new HMAC(new MD5);
+   hmac_sha1 = new HMAC(new SHA_160);
+   }
+
+TLS_PRF::~TLS_PRF()
+   {
+   delete hmac_md5;
+   delete hmac_sha1;
+   }
+
+/*
+* TLS PRF
+*/
+secure_vector<byte> TLS_PRF::derive(size_t key_len,
+                                   const byte secret[], size_t secret_len,
+                                   const byte seed[], size_t seed_len) const
+   {
+   secure_vector<byte> output(key_len);
+
+   size_t S1_len = (secret_len + 1) / 2,
+          S2_len = (secret_len + 1) / 2;
+   const byte* S1 = secret;
+   const byte* S2 = secret + (secret_len - S2_len);
+
+   P_hash(output, hmac_md5,  S1, S1_len, seed, seed_len);
+   P_hash(output, hmac_sha1, S2, S2_len, seed, seed_len);
+
+   return output;
+   }
+
+/*
+* TLS v1.2 PRF Constructor and Destructor
+*/
+TLS_12_PRF::TLS_12_PRF(MessageAuthenticationCode* mac) : hmac(mac)
+   {
+   }
+
+TLS_12_PRF::~TLS_12_PRF()
+   {
+   delete hmac;
+   }
+
+secure_vector<byte> TLS_12_PRF::derive(size_t key_len,
+                                      const byte secret[], size_t secret_len,
+                                      const byte seed[], size_t seed_len) const
+   {
+   secure_vector<byte> output(key_len);
+
+   P_hash(output, hmac, secret, secret_len, seed, seed_len);
+
+   return output;
+   }
+
+}