swaroop: encrypt decryption private key with motherboard UUID.

6 files changed, 77 insertions, 23 deletions

diff --git a/src/lib/config.cc b/src/lib/config.cc
index e61eea3a6..172890dcf 100644
--- a/src/lib/config.cc
+++ b/src/lib/config.cc
@@ -32,6 +32,7 @@
 #include "film.h"
 #include "dkdm_wrapper.h"
 #include "compose.hpp"
+#include "crypto.h"
 #include <dcp/raw_convert.h>
 #include <dcp/name_format.h>
 #include <dcp/certificate_chain.h>
@@ -61,6 +62,7 @@ using boost::shared_ptr;
 using boost::optional;
 using boost::dynamic_pointer_cast;
 using boost::algorithm::trim;
+using boost::shared_array;
 using dcp::raw_convert;
 
 Config* Config::_instance = 0;
@@ -435,7 +437,19 @@ try
 		BOOST_FOREACH (cxml::NodePtr i, decryption->node_children ("Certificate")) {
 			c->add (dcp::Certificate (i->content ()));
 		}
-		c->set_key (decryption->string_child ("PrivateKey"));
+		optional<string> key = decryption->optional_string_child ("PrivateKey");
+#ifdef DCPOMATIC_VARIANT_SWAROOP
+		if (key) {
+			c->set_key (*key);
+		} else {
+			dcp::Data encrypted_key (path("private"));
+			dcp::Data iv (path("iv"));
+			c->set_key (dcpomatic::decrypt (encrypted_key, key_from_uuid(), iv));
+		}
+#else
+		DCPOMATIC_ASSERT (key);
+		c->set_key (*key);
+#endif
 		_decryption_chain = c;
 	} else {
 		_decryption_chain = create_certificate_chain ();
@@ -599,6 +613,19 @@ Config::write () const
 	write_cinemas ();
 }
 
+#ifdef DCPOMATIC_VARIANT_SWAROOP
+/* Make up a key from the machine UUID */
+dcp::Data
+Config::key_from_uuid () const
+{
+	dcp::Data key (dcpomatic::crypto_key_length());
+	memset (key.data().get(), 0, key.size());
+	string const magic = command_and_read ("dcpomatic2_uuid");
+	strncpy ((char *) key.data().get(), magic.c_str(), dcpomatic::crypto_key_length());
+	return key;
+}
+#endif
+
 void
 Config::write_config () const
 {
@@ -771,18 +798,7 @@ 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");
@@ -790,7 +806,14 @@ Config::write_config () const
 	BOOST_FOREACH (dcp::Certificate const & i, _decryption_chain->unordered()) {
 		decryption->add_child("Certificate")->add_child_text (i.certificate (true));
 	}
+#ifdef DCPOMATIC_VARIANT_SWAROOP
+	dcp::Data iv = dcpomatic::random_iv ();
+	dcp::Data encrypted_key = dcpomatic::encrypt (_decryption_chain->key().get(), key_from_uuid(), iv);
+	encrypted_key.write (path("private"));
+	iv.write (path("iv"));
+#else
 	decryption->add_child("PrivateKey")->add_child_text (_decryption_chain->key().get ());
+#endif
 
 	/* [XML] History Filename of DCP to present in the <guilabel>File</guilabel> menu of the GUI; there can be more than one
 	   of these tags.
diff --git a/src/lib/config.h b/src/lib/config.h
index 0e5f9dfd1..e28928226 100644
--- a/src/lib/config.h
+++ b/src/lib/config.h
@@ -1083,6 +1083,9 @@ private:
 	boost::filesystem::path directory_or (boost::optional<boost::filesystem::path> dir, boost::filesystem::path a) const;
 	void add_to_history_internal (std::vector<boost::filesystem::path>& h, boost::filesystem::path p);
 	void backup ();
+#ifdef DCPOMATIC_VARIANT_SWAROOP
+	dcp::Data key_from_uuid () const;
+#endif
 
 	template <class T>
 	void maybe_set (T& member, T new_value, Property prop = OTHER) {
diff --git a/src/lib/cross.cc b/src/lib/cross.cc
index e3fb22f39..171bf2c81 100644
--- a/src/lib/cross.cc
+++ b/src/lib/cross.cc
@@ -474,3 +474,30 @@ home_directory ()
 		return boost::filesystem::path(getenv("HOMEDRIVE")) / boost::filesystem::path(getenv("HOMEPATH"));
 #endif
 }
+
+string
+command_and_read (string cmd)
+{
+#ifdef DCPOMATIC_LINUX
+	FILE* pipe = popen (cmd.c_str(), "r");
+	if (!pipe) {
+		throw runtime_error ("popen failed");
+	}
+
+	string result;
+	char buffer[128];
+	try {
+		while (fgets(buffer, sizeof(buffer), pipe)) {
+			result += buffer;
+		}
+	} catch (...) {
+		pclose (pipe);
+		throw;
+	}
+
+	pclose (pipe);
+	return result;
+#endif
+
+	return "";
+}
diff --git a/src/lib/cross.h b/src/lib/cross.h
index ee5e7919a..06e198e99 100644
--- a/src/lib/cross.h
+++ b/src/lib/cross.h
@@ -56,6 +56,7 @@ extern void start_player (boost::filesystem::path dcpomatic);
 extern uint64_t thread_id ();
 extern int avio_open_boost (AVIOContext** s, boost::filesystem::path file, int flags);
 extern boost::filesystem::path home_directory ();
+extern std::string command_and_read (std::string cmd);
 
 /** @class Waker
  *  @brief A class which tries to keep the computer awake on various operating systems.
diff --git a/src/lib/crypto.cc b/src/lib/crypto.cc
index 69e041cb2..b02a3d34c 100644
--- a/src/lib/crypto.cc
+++ b/src/lib/crypto.cc
@@ -35,24 +35,24 @@ using namespace dcpomatic;
 /** The cipher that this code uses */
 #define CIPHER EVP_aes_256_cbc()
 
-shared_array<unsigned char>
+dcp::Data
 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));
+	dcp::Data iv (EVP_CIPHER_iv_length(cipher));
+	RAND_bytes (iv.data().get(), iv.size());
 	return iv;
 }
 	
 dcp::Data
-dcpomatic::encrypt (string plaintext, shared_array<unsigned char const> key, shared_array<unsigned char const> iv)
+dcpomatic::encrypt (string plaintext, dcp::Data key, dcp::Data 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());
+	int r = EVP_EncryptInit_ex (ctx, CIPHER, 0, key.data().get(), iv.data().get());
 	if (r != 1) {
 		throw CryptoError ("could not initialise cipher context for encryption");
 	}
@@ -60,7 +60,7 @@ dcpomatic::encrypt (string plaintext, shared_array<unsigned char const> key, sha
 	dcp::Data ciphertext (plaintext.size() * 2);
 
 	int len;
-	r = EVP_EncryptUpdate (ctx, ciphertext.data().get(), &len, (unsigned char const *) plaintext.c_str(), plaintext.size());
+	r = EVP_EncryptUpdate (ctx, ciphertext.data().get(), &len, (uint8_t const *) plaintext.c_str(), plaintext.size());
 	if (r != 1) {
 		throw CryptoError ("could not encrypt data");
 	}
@@ -80,14 +80,14 @@ dcpomatic::encrypt (string plaintext, shared_array<unsigned char const> key, sha
 }
 
 string
-dcpomatic::decrypt (dcp::Data ciphertext, shared_array<unsigned char const> key, shared_array<unsigned char const> iv)
+dcpomatic::decrypt (dcp::Data ciphertext, dcp::Data key, dcp::Data 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());
+	int r = EVP_DecryptInit_ex (ctx, CIPHER, 0, key.data().get(), iv.data().get());
 	if (r != 1) {
 		throw CryptoError ("could not initialise cipher context for decryption");
 	}
diff --git a/src/lib/crypto.h b/src/lib/crypto.h
index ea46162a4..e450d4db1 100644
--- a/src/lib/crypto.h
+++ b/src/lib/crypto.h
@@ -22,9 +22,9 @@
 
 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);
+dcp::Data random_iv ();
+dcp::Data encrypt (std::string plaintext, dcp::Data key, dcp::Data iv);
+std::string decrypt (dcp::Data ciphertext, dcp::Data key, dcp::Data iv);
 int crypto_key_length ();	
 
 }