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1 // Copyright (c) 2012 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 #include "net/quic/crypto/null_decrypter.h" | |
6 #include "net/quic/quic_utils.h" | |
7 #include "net/quic/quic_data_reader.h" | |
8 | |
9 using base::StringPiece; | |
10 using std::string; | |
11 | |
12 namespace net { | |
13 | |
14 NullDecrypter::NullDecrypter() {} | |
15 | |
16 bool NullDecrypter::SetKey(StringPiece key) { return key.empty(); } | |
17 | |
18 bool NullDecrypter::SetNoncePrefix(StringPiece nonce_prefix) { | |
19 return nonce_prefix.empty(); | |
20 } | |
21 | |
22 bool NullDecrypter::DecryptPacket(QuicPacketSequenceNumber /*seq_number*/, | |
23 const StringPiece& associated_data, | |
24 const StringPiece& ciphertext, | |
25 char* output, | |
26 size_t* output_length, | |
27 size_t max_output_length) { | |
28 QuicDataReader reader(ciphertext.data(), ciphertext.length()); | |
29 uint128 hash; | |
30 | |
31 if (!ReadHash(&reader, &hash)) { | |
32 return false; | |
33 } | |
34 | |
35 StringPiece plaintext = reader.ReadRemainingPayload(); | |
36 if (plaintext.length() > max_output_length) { | |
37 LOG(DFATAL) << "Output buffer must be larger than the plaintext."; | |
38 return false; | |
39 } | |
40 if (hash != ComputeHash(associated_data, plaintext)) { | |
41 return false; | |
42 } | |
43 // Copy the plaintext to output. | |
44 memcpy(output, plaintext.data(), plaintext.length()); | |
45 *output_length = plaintext.length(); | |
46 return true; | |
47 } | |
48 | |
49 StringPiece NullDecrypter::GetKey() const { return StringPiece(); } | |
50 | |
51 StringPiece NullDecrypter::GetNoncePrefix() const { return StringPiece(); } | |
52 | |
53 bool NullDecrypter::ReadHash(QuicDataReader* reader, uint128* hash) { | |
54 uint64 lo; | |
55 uint32 hi; | |
56 if (!reader->ReadUInt64(&lo) || | |
57 !reader->ReadUInt32(&hi)) { | |
58 return false; | |
59 } | |
60 *hash = hi; | |
61 *hash <<= 64; | |
62 *hash += lo; | |
63 return true; | |
64 } | |
65 | |
66 uint128 NullDecrypter::ComputeHash(const StringPiece& data1, | |
67 const StringPiece& data2) const { | |
68 uint128 correct_hash = QuicUtils::FNV1a_128_Hash_Two( | |
69 data1.data(), data1.length(), data2.data(), data2.length()); | |
70 uint128 mask(GG_UINT64_C(0x0), GG_UINT64_C(0xffffffff)); | |
71 mask <<= 96; | |
72 correct_hash &= ~mask; | |
73 return correct_hash; | |
74 } | |
75 | |
76 } // namespace net | |
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