Incomplete encryption of private keys.

5 files changed, 174 insertions, 0 deletions

diff --git a/src/lib/config.cc b/src/lib/config.cc
index ddb4bf25a..e61eea3a6 100644
--- a/src/lib/config.cc
+++ b/src/lib/config.cc
@@ -771,7 +771,18 @@ Config::write_config () const
 	BOOST_FOREACH (dcp::Certificate const & i, _signer_chain->unordered()) {
 		signer->add_child("Certificate")->add_child_text (i.certificate (true));
 	}
+#ifdef DCPOMATIC_SWAROOP
+	FILE* f = fopen_boost (path("private"), "wb");
+	if (!f) {
+		throw FileError ("Could not open file for writing", path("private"));
+	}
+	shared_array<uint8_t> iv = dcpomatic::random_iv ();
+	dcp::Data encrypted_key = dcpomatic::encrypt (_signer_chain->key().get(), key, iv);
+	fwrite (encrypted_key.data().get(), encrypted_key.data().size(), 1, f);
+	fclose (f);
+#else	
 	signer->add_child("PrivateKey")->add_child_text (_signer_chain->key().get ());
+#endif	
 
 	/* [XML] Decryption Certificate chain and private key to use when decrypting KDMs */
 	xmlpp::Element* decryption = root->add_child ("Decryption");
diff --git a/src/lib/crypto.cc b/src/lib/crypto.cc
new file mode 100644
index 000000000..69e041cb2
--- /dev/null
+++ b/src/lib/crypto.cc
@@ -0,0 +1,123 @@
+/*
+    Copyright (C) 2018 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DCP-o-matic is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+/* Based on code from https://wiki.openssl.org/index.php/EVP_Symmetric_Encryption_and_Decryption */
+
+#include "crypto.h"
+#include "exceptions.h"
+#include <openssl/conf.h>
+#include <openssl/evp.h>
+#include <openssl/err.h>
+#include <openssl/rand.h>
+#include <boost/scoped_array.hpp>
+
+using std::string;
+using boost::shared_array;
+using namespace dcpomatic;
+
+/** The cipher that this code uses */
+#define CIPHER EVP_aes_256_cbc()
+
+shared_array<unsigned char>
+dcpomatic::random_iv ()
+{
+	EVP_CIPHER const * cipher = CIPHER;
+	shared_array<unsigned char> iv (new unsigned char[EVP_CIPHER_iv_length(cipher)]);
+	RAND_bytes (iv.get(), EVP_CIPHER_iv_length(cipher));
+	return iv;
+}
+	
+dcp::Data
+dcpomatic::encrypt (string plaintext, shared_array<unsigned char const> key, shared_array<unsigned char const> iv)
+{
+	EVP_CIPHER_CTX* ctx = EVP_CIPHER_CTX_new ();
+	if (!ctx) {
+		throw CryptoError ("could not create cipher context");
+	}
+
+	int r = EVP_EncryptInit_ex (ctx, CIPHER, 0, key.get(), iv.get());
+	if (r != 1) {
+		throw CryptoError ("could not initialise cipher context for encryption");
+	}
+
+	dcp::Data ciphertext (plaintext.size() * 2);
+
+	int len;
+	r = EVP_EncryptUpdate (ctx, ciphertext.data().get(), &len, (unsigned char const *) plaintext.c_str(), plaintext.size());
+	if (r != 1) {
+		throw CryptoError ("could not encrypt data");
+	}
+
+	int ciphertext_len = len;
+
+	r = EVP_EncryptFinal_ex (ctx, ciphertext.data().get() + len, &len);
+	if (r != 1) {
+		throw CryptoError ("could not finish encryption");
+	}
+
+	ciphertext.set_size (ciphertext_len + len);
+
+	EVP_CIPHER_CTX_free (ctx);
+
+	return ciphertext;
+}
+
+string
+dcpomatic::decrypt (dcp::Data ciphertext, shared_array<unsigned char const> key, shared_array<unsigned char const> iv)
+{
+	EVP_CIPHER_CTX* ctx = EVP_CIPHER_CTX_new ();
+	if (!ctx) {
+		throw CryptoError ("could not create cipher context");
+	}
+
+	int r = EVP_DecryptInit_ex (ctx, CIPHER, 0, key.get(), iv.get());
+	if (r != 1) {
+		throw CryptoError ("could not initialise cipher context for decryption");
+	}
+
+	dcp::Data plaintext (ciphertext.size() * 2);
+
+	int len;
+	r = EVP_DecryptUpdate (ctx, plaintext.data().get(), &len, ciphertext.data().get(), ciphertext.size());
+	if (r != 1) {
+		throw CryptoError ("could not decrypt data");
+	}
+
+	int plaintext_len = len;
+	
+	r = EVP_DecryptFinal_ex (ctx, plaintext.data().get() + len, &len);
+	if (r != 1) {
+		throw CryptoError ("could not finish decryption");
+	}
+
+	plaintext_len += len;
+	plaintext.set_size (plaintext_len + 1);
+	plaintext.data().get()[plaintext_len] = '\0';
+
+	EVP_CIPHER_CTX_free (ctx);
+
+	return string ((char *) plaintext.data().get());
+}
+
+int
+dcpomatic::crypto_key_length ()
+{
+	return EVP_CIPHER_key_length (CIPHER);
+}
diff --git a/src/lib/crypto.h b/src/lib/crypto.h
new file mode 100644
index 000000000..ea46162a4
--- /dev/null
+++ b/src/lib/crypto.h
@@ -0,0 +1,31 @@
+/*
+    Copyright (C) 2018 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DCP-o-matic is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include <dcp/data.h>
+
+namespace dcpomatic {
+	
+boost::shared_array<unsigned char> random_iv ();
+dcp::Data encrypt (std::string plaintext, boost::shared_array<unsigned char const> key, boost::shared_array<unsigned char const> iv);
+std::string decrypt (dcp::Data ciphertext, boost::shared_array<unsigned char const> key, boost::shared_array<unsigned char const> iv);
+int crypto_key_length ();	
+
+}
+
diff --git a/src/lib/exceptions.h b/src/lib/exceptions.h
index eceafa105..fe87ababc 100644
--- a/src/lib/exceptions.h
+++ b/src/lib/exceptions.h
@@ -44,6 +44,14 @@ public:
 	{}
 };
 
+class CryptoError : public std::runtime_error
+{
+public:
+	explicit CryptoError (std::string s)
+		: std::runtime_error (s)
+	{}
+};
+
 /** @class EncodeError
  *  @brief A low-level problem with an encoder.
  */
diff --git a/src/lib/wscript b/src/lib/wscript
index 62881e95d..b78f093cf 100644
--- a/src/lib/wscript
+++ b/src/lib/wscript
@@ -52,6 +52,7 @@ sources = """
           content.cc
           content_factory.cc
           cross.cc
+          crypto.cc
           curl_uploader.cc
           dcp.cc
           dcp_content.cc