wipcheck-signatures

2 files changed, 37 insertions, 0 deletions

diff --git a/src/verify.cc b/src/verify.cc
index a0c329d0..410d32e8 100644
--- a/src/verify.cc
+++ b/src/verify.cc
@@ -76,6 +76,7 @@
 #include <xercesc/parsers/XercesDOMParser.hpp>
 #include <xercesc/sax/HandlerBase.hpp>
 #include <xercesc/util/PlatformUtils.hpp>
+#include <xmlsec/xmldsig.h>
 #include <boost/algorithm/string.hpp>
 #include <iostream>
 #include <map>
@@ -1256,6 +1257,33 @@ pkl_has_encrypted_assets (shared_ptr<DCP> dcp, shared_ptr<PKL> pkl)
 }
 
 
+static void
+verify_signature (boost::filesystem::path xml_file, vector<VerificationNote>& notes)
+{
+	cxml::Document doc;
+	doc.read_file (xml_file);
+
+	auto signature = doc.optional_node_child("Signature");
+	if (!signature) {
+		return;
+	}
+
+	auto context = xmlSecDSigCtxCreate (0);
+	if (context == nullptr) {
+		throw MiscError ("could not create signature context");
+	}
+
+	context->signKey = xmlSecCryptoAppKeyLoadMemory(
+		reinterpret_cast<const unsigned char *>(_key->c_str()), _key->size(), xmlSecKeyDataFormatPem, 0, 0, 0
+		);
+
+	auto r = xmlSecDSigCtxVerify (context, signature->node()->cobj());
+	if (r < 0) {
+		notes.push_back (dcp::VerificationNote(VerificationNote::Type::ERROR, VerificationNote::Code::INVALID_SIGNATURE, xml_file));
+	}
+}
+
+
 vector<VerificationNote>
 dcp::verify (
 	vector<boost::filesystem::path> directories,
@@ -1306,6 +1334,7 @@ dcp::verify (
 		for (auto cpl: dcp->cpls()) {
 			stage ("Checking CPL", cpl->file());
 			validate_xml (cpl->file().get(), *xsd_dtd_directory, notes);
+			verify_signature (cpl->file().get(), notes);
 
 			if (cpl->any_encrypted() && !cpl->all_encrypted()) {
 				notes.push_back ({VerificationNote::Type::BV21_ERROR, VerificationNote::Code::PARTIALLY_ENCRYPTED});
@@ -1553,6 +1582,7 @@ dcp::verify (
 		for (auto pkl: dcp->pkls()) {
 			stage ("Checking PKL", pkl->file());
 			validate_xml (pkl->file().get(), *xsd_dtd_directory, notes);
+			verify_signature (pkl->file().get(), notes);
 			if (pkl_has_encrypted_assets(dcp, pkl)) {
 				cxml::Document doc ("PackingList");
 				doc.read_file (pkl->file().get());
@@ -1763,6 +1793,8 @@ dcp::note_to_string (VerificationNote note)
 		return "Some closed <Text> or <Image> nodes have different vertical alignments within a <Subtitle>.";
 	case VerificationNote::Code::INCORRECT_CLOSED_CAPTION_ORDERING:
 		return "Some closed captions are not listed in the order of their vertical position.";
+	case VerificationNote::Code::INVALID_SIGNATURE:
+		return "An XML file has an invalid signature.";
 	}
 
 	return "";
@@ -1815,3 +1847,4 @@ dcp::operator<< (std::ostream& s, dcp::VerificationNote const& note)
 	return s;
 }
 
+
diff --git a/src/verify.h b/src/verify.h
index 424b29e7..1fd9f5f4 100644
--- a/src/verify.h
+++ b/src/verify.h
@@ -392,6 +392,10 @@ public:
 		MISMATCHED_CLOSED_CAPTION_VALIGN,
 		/** Some closed captions are not listed in the XML in the order of their vertical position */
 		INCORRECT_CLOSED_CAPTION_ORDERING,
+		/** An XML file has an invalid signature
+		 *  file contains the XML filename
+		 */
+		INVALID_SIGNATURE,
 	};
 
 	VerificationNote (Type type, Code code)