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/* -*- 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
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