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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 //
      5 // Some helpers for quic crypto
      6 
      7 #ifndef NET_QUIC_CRYPTO_CRYPTO_UTILS_H_
      8 #define NET_QUIC_CRYPTO_CRYPTO_UTILS_H_
      9 
     10 #include <string>
     11 
     12 #include "base/strings/string_piece.h"
     13 #include "net/base/net_export.h"
     14 #include "net/quic/crypto/crypto_handshake.h"
     15 #include "net/quic/crypto/crypto_protocol.h"
     16 #include "net/quic/quic_protocol.h"
     17 #include "net/quic/quic_time.h"
     18 
     19 namespace net {
     20 
     21 class QuicTime;
     22 class QuicRandom;
     23 struct QuicCryptoNegotiatedParameters;
     24 
     25 class NET_EXPORT_PRIVATE CryptoUtils {
     26  public:
     27   enum Perspective {
     28     SERVER,
     29     CLIENT,
     30   };
     31 
     32   // Generates the connection nonce. The nonce is formed as:
     33   //   <4 bytes> current time
     34   //   <8 bytes> |orbit| (or random if |orbit| is empty)
     35   //   <20 bytes> random
     36   static void GenerateNonce(QuicWallTime now,
     37                             QuicRandom* random_generator,
     38                             base::StringPiece orbit,
     39                             std::string* nonce);
     40 
     41   // Returns true if the sni is valid, false otherwise.
     42   //  (1) disallow IP addresses;
     43   //  (2) check that the hostname contains valid characters only; and
     44   //  (3) contains at least one dot.
     45   static bool IsValidSNI(base::StringPiece sni);
     46 
     47   // Convert hostname to lowercase and remove the trailing '.'.
     48   // Returns |hostname|. NormalizeHostname() doesn't support IP address
     49   // literals. IsValidSNI() should be called before calling NormalizeHostname().
     50   static std::string NormalizeHostname(const char* hostname);
     51 
     52   // DeriveKeys populates |crypters->encrypter|, |crypters->decrypter|, and
     53   // |subkey_secret| (optional -- may be null) given the contents of
     54   // |premaster_secret|, |client_nonce|, |server_nonce| and |hkdf_input|. |aead|
     55   // determines which cipher will be used. |perspective| controls whether the
     56   // server's keys are assigned to |encrypter| or |decrypter|. |server_nonce| is
     57   // optional and, if non-empty, is mixed into the key derivation.
     58   // |subkey_secret| will have the same length as |premaster_secret|.
     59   static bool DeriveKeys(base::StringPiece premaster_secret,
     60                          QuicTag aead,
     61                          base::StringPiece client_nonce,
     62                          base::StringPiece server_nonce,
     63                          const std::string& hkdf_input,
     64                          Perspective perspective,
     65                          CrypterPair* crypters,
     66                          std::string* subkey_secret);
     67 
     68   // Performs key extraction to derive a new secret of |result_len| bytes
     69   // dependent on |subkey_secret|, |label|, and |context|. Returns false if the
     70   // parameters are invalid (e.g. |label| contains null bytes); returns true on
     71   // success.
     72   static bool ExportKeyingMaterial(base::StringPiece subkey_secret,
     73                                    base::StringPiece label,
     74                                    base::StringPiece context,
     75                                    size_t result_len,
     76                                    std::string* result);
     77 
     78  private:
     79   DISALLOW_COPY_AND_ASSIGN(CryptoUtils);
     80 };
     81 
     82 }  // namespace net
     83 
     84 #endif  // NET_QUIC_CRYPTO_CRYPTO_UTILS_H_
     85