Add option to ignore mismatched HMACs when reading MXFs.

9 files changed, 32 insertions, 17 deletions

diff --git a/src/asset_reader.h b/src/asset_reader.h
index 2da67bd8..8478b51f 100644
--- a/src/asset_reader.h
+++ b/src/asset_reader.h
@@ -72,13 +72,17 @@ public:
 	std::shared_ptr<const F> get_frame (int n) const
 	{
 		/* Can't use make_shared here as the constructor is private */
-		return std::shared_ptr<const F> (new F(_reader, n, _crypto_context));
+		return std::shared_ptr<const F> (new F(_reader, n, _crypto_context, _check_hmac));
 	}
 
 	R* reader () const {
 		return _reader;
 	}
 
+	void set_check_hmac (bool check) {
+		_check_hmac = check;
+	}
+
 protected:
 	R* _reader = nullptr;
 	std::shared_ptr<DecryptionContext> _crypto_context;
@@ -100,6 +104,8 @@ private:
 			boost::throw_exception (FileError("could not open MXF file for reading", asset->file().get(), r));
 		}
 	}
+
+	bool _check_hmac = true;
 };
 
 
diff --git a/src/frame.h b/src/frame.h
index 74bd616f..01dfe8b4 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -54,12 +54,12 @@ template <class R, class B>
 class Frame
 {
 public:
-	Frame (R* reader, int n, std::shared_ptr<const DecryptionContext> c)
+	Frame (R* reader, int n, std::shared_ptr<const DecryptionContext> c, bool check_hmac)
 	{
 		/* XXX: unfortunate guesswork on this buffer size */
 		_buffer = std::make_shared<B>(Kumu::Megabyte);
 
-		if (ASDCP_FAILURE(reader->ReadFrame(n, *_buffer, c->context(), c->hmac()))) {
+		if (ASDCP_FAILURE(reader->ReadFrame(n, *_buffer, c->context(), check_hmac ? c->hmac() : nullptr))) {
 			boost::throw_exception (ReadError ("could not read frame"));
 		}
 	}
diff --git a/src/mono_picture_frame.cc b/src/mono_picture_frame.cc
index fb451e08..df75126c 100644
--- a/src/mono_picture_frame.cc
+++ b/src/mono_picture_frame.cc
@@ -80,13 +80,14 @@ MonoPictureFrame::MonoPictureFrame (boost::filesystem::path path)
  *  @param reader Reader for the asset's MXF file.
  *  @param n Frame within the asset, not taking EntryPoint into account.
  *  @param c Context for decryption, or 0.
+ *  @param check_hmac true to check the HMAC and give an error if it is not as expected.
  */
-MonoPictureFrame::MonoPictureFrame (ASDCP::JP2K::MXFReader* reader, int n, shared_ptr<DecryptionContext> c)
+MonoPictureFrame::MonoPictureFrame (ASDCP::JP2K::MXFReader* reader, int n, shared_ptr<DecryptionContext> c, bool check_hmac)
 {
 	/* XXX: unfortunate guesswork on this buffer size */
 	_buffer = make_shared<ASDCP::JP2K::FrameBuffer>(4 * Kumu::Megabyte);
 
-	auto const r = reader->ReadFrame (n, *_buffer, c->context(), c->hmac());
+	auto const r = reader->ReadFrame (n, *_buffer, c->context(), check_hmac ? c->hmac() : nullptr);
 
 	if (ASDCP_FAILURE(r)) {
 		boost::throw_exception (ReadError(String::compose ("could not read video frame %1 (%2)", n, static_cast<int>(r))));
diff --git a/src/mono_picture_frame.h b/src/mono_picture_frame.h
index 95b0d111..3ca16bf2 100644
--- a/src/mono_picture_frame.h
+++ b/src/mono_picture_frame.h
@@ -101,7 +101,7 @@ private:
 	*/
 	friend class AssetReader<ASDCP::JP2K::MXFReader, MonoPictureFrame>;
 
-	MonoPictureFrame (ASDCP::JP2K::MXFReader* reader, int n, std::shared_ptr<DecryptionContext>);
+	MonoPictureFrame (ASDCP::JP2K::MXFReader* reader, int n, std::shared_ptr<DecryptionContext>, bool check_hmac);
 
 	std::shared_ptr<ASDCP::JP2K::FrameBuffer> _buffer;
 };
diff --git a/src/sound_frame.cc b/src/sound_frame.cc
index 9c8087c2..25845d88 100644
--- a/src/sound_frame.cc
+++ b/src/sound_frame.cc
@@ -46,8 +46,8 @@ using std::cout;
 using namespace dcp;
 
 
-SoundFrame::SoundFrame (ASDCP::PCM::MXFReader* reader, int n, std::shared_ptr<const DecryptionContext> c)
-	: Frame<ASDCP::PCM::MXFReader, ASDCP::PCM::FrameBuffer> (reader, n, c)
+SoundFrame::SoundFrame (ASDCP::PCM::MXFReader* reader, int n, std::shared_ptr<const DecryptionContext> c, bool check_hmac)
+	: Frame<ASDCP::PCM::MXFReader, ASDCP::PCM::FrameBuffer> (reader, n, c, check_hmac)
 {
 	ASDCP::PCM::AudioDescriptor desc;
 	reader->FillAudioDescriptor (desc);
diff --git a/src/sound_frame.h b/src/sound_frame.h
index 85082299..0f5021e2 100644
--- a/src/sound_frame.h
+++ b/src/sound_frame.h
@@ -51,7 +51,7 @@ namespace dcp {
 class SoundFrame : public Frame<ASDCP::PCM::MXFReader, ASDCP::PCM::FrameBuffer>
 {
 public:
-	SoundFrame (ASDCP::PCM::MXFReader* reader, int n, std::shared_ptr<const DecryptionContext> c);
+	SoundFrame (ASDCP::PCM::MXFReader* reader, int n, std::shared_ptr<const DecryptionContext> c, bool check_hmac);
 	int channels () const;
 	int samples () const;
 	int32_t get (int channel, int sample) const;
diff --git a/src/stereo_picture_frame.cc b/src/stereo_picture_frame.cc
index 4cb9f2a1..8d3a2757 100644
--- a/src/stereo_picture_frame.cc
+++ b/src/stereo_picture_frame.cc
@@ -94,13 +94,14 @@ StereoPictureFrame::Part::size () const
 /** Make a picture frame from a 3D (stereoscopic) asset.
  *  @param reader Reader for the MXF file.
  *  @param n Frame within the asset, not taking EntryPoint into account.
+ *  @param check_hmac true to check the HMAC and give an error if it is not as expected.
  */
-StereoPictureFrame::StereoPictureFrame (ASDCP::JP2K::MXFSReader* reader, int n, shared_ptr<DecryptionContext> c)
+StereoPictureFrame::StereoPictureFrame (ASDCP::JP2K::MXFSReader* reader, int n, shared_ptr<DecryptionContext> c, bool check_hmac)
 {
 	/* XXX: unfortunate guesswork on this buffer size */
 	_buffer = make_shared<ASDCP::JP2K::SFrameBuffer>(4 * Kumu::Megabyte);
 
-	if (ASDCP_FAILURE (reader->ReadFrame (n, *_buffer, c->context(), c->hmac()))) {
+	if (ASDCP_FAILURE (reader->ReadFrame (n, *_buffer, c->context(), check_hmac ? c->hmac() : nullptr))) {
 		boost::throw_exception (ReadError (String::compose ("could not read video frame %1 of %2", n)));
 	}
 }
diff --git a/src/stereo_picture_frame.h b/src/stereo_picture_frame.h
index 096c821a..09d684c4 100644
--- a/src/stereo_picture_frame.h
+++ b/src/stereo_picture_frame.h
@@ -105,7 +105,7 @@ private:
 	*/
 	friend class AssetReader<ASDCP::JP2K::MXFSReader, StereoPictureFrame>;
 
-	StereoPictureFrame (ASDCP::JP2K::MXFSReader* reader, int n, std::shared_ptr<DecryptionContext>);
+	StereoPictureFrame (ASDCP::JP2K::MXFSReader* reader, int n, std::shared_ptr<DecryptionContext>, bool check_hmac);
 
 	std::shared_ptr<ASDCP::JP2K::SFrameBuffer> _buffer;
 };
diff --git a/tools/dcpdecryptmxf.cc b/tools/dcpdecryptmxf.cc
index cf8df735..4c615f99 100644
--- a/tools/dcpdecryptmxf.cc
+++ b/tools/dcpdecryptmxf.cc
@@ -68,13 +68,15 @@ help (string n)
 	     << "  -o, --output       output filename\n"
 	     << "  -k, --kdm          KDM file\n"
 	     << "  -p, --private-key  private key file\n"
-	     << "  -t, --type         MXF type: picture or atmos\n";
+	     << "  -t, --type         MXF type: picture or atmos\n"
+	     << "  -i, --ignore-hmac  don't raise an error if HMACs don't agree\n";
 }
 
 template <class T, class U>
-void copy (T const& in, shared_ptr<U> writer)
+void copy (T const& in, shared_ptr<U> writer, bool ignore_hmac)
 {
 	auto reader = in.start_read();
+	reader->set_check_hmac (!ignore_hmac);
 	for (int64_t i = 0; i < in.intrinsic_duration(); ++i) {
 		auto frame = reader->get_frame (i);
 		writer->write (frame->data(), frame->size());
@@ -92,6 +94,7 @@ main (int argc, char* argv[])
 	optional<boost::filesystem::path> output_file;
 	optional<boost::filesystem::path> kdm_file;
 	optional<boost::filesystem::path> private_key_file;
+	bool ignore_hmac = false;
 
 	enum class Type {
 		PICTURE,
@@ -110,10 +113,11 @@ main (int argc, char* argv[])
 			{ "kdm", required_argument, 0, 'k'},
 			{ "private-key", required_argument, 0, 'p'},
 			{ "type", required_argument, 0, 't' },
+			{ "ignore-hmac", no_argument, 0, 'i' },
 			{ 0, 0, 0, 0 }
 		};
 
-		int c = getopt_long (argc, argv, "Avho:k:p:t:", long_options, &option_index);
+		int c = getopt_long (argc, argv, "Avho:k:p:t:i", long_options, &option_index);
 
 		if (c == -1) {
 			break;
@@ -148,6 +152,9 @@ main (int argc, char* argv[])
 				exit (EXIT_FAILURE);
 			}
 			break;
+		case 'i':
+			ignore_hmac = true;
+			break;
 		}
 	}
 
@@ -214,7 +221,7 @@ main (int argc, char* argv[])
 				in.atmos_version()
 				);
 			auto writer = out.start_write (output_file.get());
-			copy (in, writer);
+			copy (in, writer, ignore_hmac);
 			break;
 		}
 		case Type::PICTURE:
@@ -223,7 +230,7 @@ main (int argc, char* argv[])
 			add_key (in, decrypted_kdm);
 			dcp::MonoPictureAsset out (in.edit_rate(), dcp::Standard::SMPTE);
 			auto writer = out.start_write (output_file.get(), false);
-			copy (in, writer);
+			copy (in, writer, ignore_hmac);
 			break;
 		}
 		}