summaryrefslogtreecommitdiffstats
path: root/security/nss/gtests/ssl_gtest/ssl_fragment_unittest.cc
blob: 64b824786d009c08127f250732e63cf1ce284ac9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "secerr.h"
#include "ssl.h"
#include "sslerr.h"
#include "sslproto.h"

#include "gtest_utils.h"
#include "scoped_ptrs.h"
#include "tls_connect.h"
#include "tls_filter.h"
#include "tls_parser.h"

namespace nss_test {

// This class cuts every unencrypted handshake record into two parts.
class RecordFragmenter : public PacketFilter {
 public:
  RecordFragmenter() : sequence_number_(0), splitting_(true) {}

 private:
  class HandshakeSplitter {
   public:
    HandshakeSplitter(const DataBuffer& input, DataBuffer* output,
                      uint64_t* sequence_number)
        : input_(input),
          output_(output),
          cursor_(0),
          sequence_number_(sequence_number) {}

   private:
    void WriteRecord(TlsRecordHeader& record_header,
                     DataBuffer& record_fragment) {
      TlsRecordHeader fragment_header(record_header.version(),
                                      record_header.content_type(),
                                      *sequence_number_);
      ++*sequence_number_;
      if (::g_ssl_gtest_verbose) {
        std::cerr << "Fragment: " << fragment_header << ' ' << record_fragment
                  << std::endl;
      }
      cursor_ = fragment_header.Write(output_, cursor_, record_fragment);
    }

    bool SplitRecord(TlsRecordHeader& record_header, DataBuffer& record) {
      TlsParser parser(record);
      while (parser.remaining()) {
        TlsHandshakeFilter::HandshakeHeader handshake_header;
        DataBuffer handshake_body;
        bool complete = false;
        if (!handshake_header.Parse(&parser, record_header, DataBuffer(),
                                    &handshake_body, &complete)) {
          ADD_FAILURE() << "couldn't parse handshake header";
          return false;
        }
        if (!complete) {
          ADD_FAILURE() << "don't want to deal with fragmented messages";
          return false;
        }

        DataBuffer record_fragment;
        // We can't fragment handshake records that are too small.
        if (handshake_body.len() < 2) {
          handshake_header.Write(&record_fragment, 0U, handshake_body);
          WriteRecord(record_header, record_fragment);
          continue;
        }

        size_t cut = handshake_body.len() / 2;
        handshake_header.WriteFragment(&record_fragment, 0U, handshake_body, 0U,
                                       cut);
        WriteRecord(record_header, record_fragment);

        handshake_header.WriteFragment(&record_fragment, 0U, handshake_body,
                                       cut, handshake_body.len() - cut);
        WriteRecord(record_header, record_fragment);
      }
      return true;
    }

   public:
    bool Split() {
      TlsParser parser(input_);
      while (parser.remaining()) {
        TlsRecordHeader header;
        DataBuffer record;
        if (!header.Parse(0, &parser, &record)) {
          ADD_FAILURE() << "bad record header";
          return false;
        }

        if (::g_ssl_gtest_verbose) {
          std::cerr << "Record: " << header << ' ' << record << std::endl;
        }

        // Don't touch packets from a non-zero epoch.  Leave these unmodified.
        if ((header.sequence_number() >> 48) != 0ULL) {
          cursor_ = header.Write(output_, cursor_, record);
          continue;
        }

        // Just rewrite the sequence number (CCS only).
        if (header.content_type() != kTlsHandshakeType) {
          EXPECT_EQ(kTlsChangeCipherSpecType, header.content_type());
          WriteRecord(header, record);
          continue;
        }

        if (!SplitRecord(header, record)) {
          return false;
        }
      }
      return true;
    }

   private:
    const DataBuffer& input_;
    DataBuffer* output_;
    size_t cursor_;
    uint64_t* sequence_number_;
  };

 protected:
  virtual PacketFilter::Action Filter(const DataBuffer& input,
                                      DataBuffer* output) override {
    if (!splitting_) {
      return KEEP;
    }

    output->Allocate(input.len());
    HandshakeSplitter splitter(input, output, &sequence_number_);
    if (!splitter.Split()) {
      // If splitting fails, we obviously reached encrypted packets.
      // Stop splitting from that point onward.
      splitting_ = false;
      return KEEP;
    }

    return CHANGE;
  }

 private:
  uint64_t sequence_number_;
  bool splitting_;
};

TEST_P(TlsConnectDatagram, FragmentClientPackets) {
  client_->SetPacketFilter(std::make_shared<RecordFragmenter>());
  Connect();
  SendReceive();
}

TEST_P(TlsConnectDatagram, FragmentServerPackets) {
  server_->SetPacketFilter(std::make_shared<RecordFragmenter>());
  Connect();
  SendReceive();
}

}  // namespace nss_test