Close #89: ta.key for OpenVPN tls-auth

The ta-key will be generated on-demand and assigned to the
issuing CA. All issued certificates of this CA will use the
same ta-key.

It can be exported as single file and will also be part of the
exported openvpn configuration file.

Extend export tests to validate the output of ta-keys
and adapt the OpenVPN conf file export test to also check the ta-key.

lib/database_model.cpp

@@ -72,8 +72,8 @@ const QString &database_model::detect_provider()
 
 QSqlError database_model::initSqlDB()
 {
-#define MAX_SCHEMAS 7
-#define SCHEMA_VERSION "7"
+#define MAX_SCHEMAS 8
+#define SCHEMA_VERSION "8"
 
 	QStringList schemas[MAX_SCHEMAS];
 

lib/database_schema.cpp

@@ -305,6 +305,16 @@
 << "UPDATE settings SET value='7' WHERE key_='schema'"
 	;
 
+	schemas[7]
+// OpenVPN TA (tls-auth) keys associated to the CA to be
+// the same for all issued certificates
+<< "CREATE TABLE takeys ("
+	"item INTEGER UNIQUE, "        // reference to items(id) of the CA
+	"value " B64_BLOB ", "         // The base64 encoded 2048 bit key
+	"FOREIGN KEY (item) REFERENCES items (id))"
+<< "UPDATE settings SET value='8' WHERE key_='schema'"
+	;
+
 /* When adding new tables or views, also add them to the list
  * in XSqlQuery::rewriteQuery(QString) in lib/sql.cpp
  */

lib/db_x509.cpp

@@ -566,11 +566,11 @@ int db_x509::exportFlags(const QModelIndex &idx) const
 	return disable_flags;
 }
 
-void db_x509::writeTaggedPEM(BioByteArray &b, const QString &tag, XFile &file)
+void db_x509::writeTaggedPEM(const BioByteArray &b, const QString &tag, XFile &file)
 {
 	if (b.size() > 0) {
 		file.write(QString("<%1>\n").arg(tag).toLatin1());
-		file.write(b);
+		file.write(b.byteArray());
 		file.write(QString("</%1>\n").arg(tag).toLatin1());
 	}
 }
@@ -609,6 +609,7 @@ void db_x509::exportItems(const QModelIndexList &list,
 			writeTaggedPEM(extra, "extra-certs", file);
 			writeTaggedPEM(cert, "cert", file);
 			writeTaggedPEM(key, "key", file);
+			writeTaggedPEM(crt->getTaKey().toLatin1(), "tls-auth", file);
 		} else if (xport->match_all(F_CHAIN)) {
 			for (; crt && crt != oldcrt; oldcrt = crt, crt = crt->getSigner())
 				crt->writeCert(file, true);
@@ -655,6 +656,8 @@ void db_x509::exportItems(const QModelIndexList &list,
 		writeVcalendar(file, vcal);
 	} else if (xport->match_all(F_CONFIG)) {
 		crt->opensslConf(file);
+	} else if (xport->match_all(F_TAKEY)) {
+		file.write(crt->getTaKey().toLatin1());
 	}
 }
 

lib/db_x509.h

@@ -23,7 +23,7 @@ class db_x509: public db_x509super
 {
 	Q_OBJECT
 
-		static void writeTaggedPEM(BioByteArray &b,
+		static void writeTaggedPEM(const BioByteArray &b,
 						const QString &tag, XFile &file);
 	protected:
 		dbheaderList getHeaders();

lib/pki_export.cpp

@@ -77,6 +77,7 @@ new pki_export(16, x509, "txt", tr("Certificate Index file"), F_INDEX | F_CA,
 new pki_export(17, x509, "ics", tr("vCalendar"),     F_CAL,                                  tr("vCalendar expiry reminder for the selected items")),
 new pki_export(18, x509, "ics", tr("CA vCalendar"),  F_CAL | F_CA,                           tr("vCalendar expiry reminder containing all issued, valid certificates, the CA itself and the latest CRL")),
 new pki_export(38, x509, "conf", tr("OpenSSL config"), F_SINGLE | F_CONFIG,                  tr("OpenSSL configuration file to create a certificate or request with the openssl commandline tool")),
+new pki_export(39, x509, "key", tr("OpenVPN tls-auth key"), F_SINGLE | F_TAKEY,              tr("The OpenVPN tls-auth key is a secret key shared between endpoints")),
 
 new pki_export(19, asym_key, "pem", tr("PEM public"),    F_PEM | F_CLIPBOARD,                            tr("Text format of the public key in one PEM file")),
 new pki_export(20, asym_key, "pem", tr("PEM private"),   F_PEM | F_PRIVATE | F_USUAL | F_CLIPBOARD,      tr("Unencrypted private key in text format")),

lib/pki_export.h

@@ -49,6 +49,7 @@ enum {
 	F_DER       = BIT(19),/* DER format */
 	F_OVPN      = BIT(20),/* OpenVPN format */
 	F_CONFIG    = BIT(21),/* OpenSSL config format */
+	F_TAKEY     = BIT(22),/* OpenVPN TLS-Auth key */
 };
 
 class pki_export : public QObject {

lib/pki_x509.cpp

@@ -17,6 +17,8 @@
 #include "exception.h"
 #include "pass_info.h"
 
+#include <openssl/rand.h>
+
 pki_x509::pki_x509(X509 *c)
 	:pki_x509super(), cert(c)
 {
@@ -143,6 +145,7 @@ QSqlError pki_x509::deleteSqlData()
 		<< "UPDATE crls SET issuer=NULL WHERE issuer=?"
 		<< "UPDATE certs SET issuer=NULL WHERE issuer=?"
 		<< "DELETE FROM revocations WHERE caId=?"
+		<< "DELETE FROM takeys WHERE item=?"
 		;
 	foreach(QString task, tasks) {
 		SQL_PREPARE(q, task);
@@ -273,6 +276,42 @@ pki_x509 *pki_x509::getBySerial(const a1int &a) const
 	return NULL;
 }
 
+QString pki_x509::getTaKey()
+{
+	XSqlQuery q;
+	QByteArray b;
+	pki_x509 *issuer = getSigner();
+	if (!isCA() && issuer && issuer != this)
+		return issuer->getTaKey();
+
+	Transaction;
+	if (!TransBegin())
+		return QString();
+
+	SQL_PREPARE(q, "SELECT value FROM takeys WHERE item = ?");
+	q.bindValue(0, sqlItemId);
+	q.exec();
+	if (q.next()) {
+		b = QByteArray::fromBase64(q.value(0).toByteArray());
+		qDebug() << "Loaded TA key" << this << b.size() << QString::fromLatin1(b.toHex()).left(6);
+	} else {
+		b.resize(2048/8);
+		RAND_bytes((unsigned char*)b.data(), 2048/8);
+		SQL_PREPARE(q, "INSERT INTO takeys (item, value) VALUES ( ?, ? )");
+		q.bindValue(0, sqlItemId);
+		q.bindValue(1, b.toBase64());
+		q.exec();
+		qDebug() << "Generated TA key" << this << b.size() << QString::fromLatin1(b.toHex()).left(6);
+	}
+	TransCommit();
+	QString takey("-----BEGIN OpenVPN Static key V1-----\n");
+	QString hex(QString::fromLatin1(b.toHex()));
+	for (int i=0; i<16; i++)
+		takey += hex.mid(32*i, 32) + "\n";
+	takey += "-----END OpenVPN Static key V1-----\n";
+	return takey;
+}
+
 a1int pki_x509::hashInfo(const EVP_MD *md) const
 {
 	unsigned char digest[EVP_MAX_MD_SIZE];

lib/pki_x509.h

@@ -163,6 +163,7 @@ class pki_x509 : public pki_x509super
 		void restoreSql(const QSqlRecord &rec);
 		QStringList icsVEVENT() const;
 		QStringList icsVEVENT_ca() const;
+		QString getTaKey();
 };
 
 Q_DECLARE_METATYPE(pki_x509 *);

lib/sql.cpp

@@ -125,7 +125,7 @@ QString XSqlQuery::rewriteQuery(QString _q)
 		"items" , "crls" , "private_keys" , "public_keys" ,
 		"tokens" , "token_mechanism" , "templates" , "certs" ,
 		"authority" , "revocations" , "requests" , "x509super" ,
-		"settings" ,
+		"settings" , "takeys",
 
 		"view_public_keys" , "view_certs" , "view_requests" ,
 		"view_crls" , "view_templates" , "view_private",

test/export.cpp

@@ -24,14 +24,14 @@
 void check_pems(const QString &name, int n, QStringList matches = QStringList())
 {
 	int begin = 0, end = 0;
-	qWarning() << "Expecting" << n << "PEMs in" << name;
+	qDebug() << "Expecting" << n << "PEMs in" << name;
 
 #if 0
 	// This is an endless loop: open_read() succeeds,
 	// but isOpen returns false. Stop investigating, use POSIX open()
 	XFile F(name);
 	while (!F.isOpen()) {
-		qWarning() << "OPEN" << name;
+		qDebug() << "OPEN" << name;
 		F.close();
 		Q_ASSERT(F.open_read());
 	}
@@ -45,7 +45,7 @@ void check_pems(const QString &name, int n, QStringList matches = QStringList())
 	QByteArray all(buf, ret);
 	close(fd);
 #endif
-	qWarning() << "ALL" << name << all.size();
+	qDebug() << "ALL" << name << all.size();
 
 	foreach(QByteArray b, all.split('\n')) {
 		if (b.indexOf("-----BEGIN ") == 0)
@@ -63,7 +63,7 @@ void check_pems(const QString &name, int n, QStringList matches = QStringList())
 	QCOMPARE(begin, n);
 	QCOMPARE(end, n);
 	foreach(QString m, matches) {
-		qWarning() << QString("Pattern %1 not found in %2").arg(m).arg(name);
+		qDebug() << QString("Pattern %1 not found in %2").arg(m).arg(name);
 	}
 	QCOMPARE(matches.size(), 0);
 }
@@ -76,7 +76,7 @@ void verify_key(const QString &name, QList<unsigned> hashes, bool priv)
 	QCOMPARE(pems->get().size(), hashes.size());
 	foreach (pki_base *pki, pems->get()) {
 		unsigned hash = pki->hash();
-		qWarning() << pki->getIntName() << hash;
+		qDebug() << pki->getIntName() << hash;
 		QVERIFY2(hashes.contains(hash),
 			qPrintable(QString("%1 not expected in %2")
 				.arg(pki->getIntName())
@@ -220,10 +220,11 @@ void test_main::exportFormat()
 	export_by_id(4, file, list, certs);
 	verify_key(file, QList<unsigned> {
 			ROOT_HASH, INTER_HASH, END_HASH, ENDKEY_HASH }, true);
-	check_pems(file, 4, QStringList { " RSA PRIVATE KEY-",
+	check_pems(file, 5, QStringList { " RSA PRIVATE KEY-",
 		" CERTIFICATE-", " CERTIFICATE-"," CERTIFICATE-",
 		"<ca>", "</ca>", "<extra-certs>", "</extra-certs>",
-		"<cert>", "</cert>", "<key>", "</key>" });
+		"<cert>", "</cert>", "<key>", "</key>",
+		"<tls-auth>", "</tls-auth>" });
 	// Export Endentity as PKCS#7
 	file = AUTOFILE(CERTP7)
 	export_by_id(8, file, list, certs);
@@ -235,9 +236,15 @@ void test_main::exportFormat()
 	verify_file(file, QList<unsigned> { ROOT_HASH, INTER_HASH, END_HASH });
 	check_pems(file, 0);
 	// Export Endentity as DER certificate
+	file = AUTOFILE(CERTDER)
 	export_by_id(13, file, list, certs);
 	verify_file(file, QList<unsigned> {  END_HASH });
 	check_pems(file, 0);
+	// Export Endentity as OpenVPN config file
+	file = AUTOFILE(OPENVPNTA)
+	export_by_id(39, file, list, certs);
+	check_pems(file, 1, QStringList {
+		"BEGIN OpenVPN Static key V1", "END OpenVPN Static key V1" });
 
 	// Export Endentity key
 	list.clear();

test/main.cpp

@@ -68,6 +68,7 @@ void test_main::openDB()
 		new pw_expect("testdbpass", pw_ok),
 	});
 	mainwin->close_database();
+	QFile::remove("testdb.xdb");
 	Database.open("testdb.xdb");
 	Settings["pkcs12_keep_legacy"] = true;
 	mainwin->setup_open_database();