Merge commit '86cc97e55fe346502462284d2e636a2b3708163e' as 'Sources/OpenVPN3'

Sources/OpenVPN3/openvpn/crypto/bs64_data_limit.hpp

@@ -0,0 +1,45 @@
+//    OpenVPN -- An application to securely tunnel IP networks
+//               over a single port, with support for SSL/TLS-based
+//               session authentication and key exchange,
+//               packet encryption, packet authentication, and
+//               packet compression.
+//
+//    Copyright (C) 2012-2017 OpenVPN Inc.
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Affero General Public License Version 3
+//    as published by the Free Software Foundation.
+//
+//    This program 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 Affero General Public License for more details.
+//
+//    You should have received a copy of the GNU Affero General Public License
+//    along with this program in the COPYING file.
+//    If not, see <http://www.gnu.org/licenses/>.
+
+// Special data limits on Blowfish, Triple DES, and other 64-bit
+// block-size ciphers vulnerable to "Sweet32" birthday attack
+// (CVE-2016-6329).  Limit such cipher keys to no more than 64 MB
+// of data encrypted/decrypted.  Note that we trigger early at
+// 48 MB to compensate for possible delays in renegotiation and
+// rollover to the new key.
+
+#ifndef OPENVPN_CRYPTO_DATALIMIT_H
+#define OPENVPN_CRYPTO_DATALIMIT_H
+
+#include <openvpn/crypto/cryptoalgs.hpp>
+
+#ifndef OPENVPN_BS64_DATA_LIMIT
+#define OPENVPN_BS64_DATA_LIMIT 48000000
+#endif
+
+namespace openvpn {
+  inline bool is_bs64_cipher(const CryptoAlgs::Type cipher)
+  {
+    return CryptoAlgs::get(cipher).block_size() == 8;
+  }
+}
+
+#endif