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// Copyright (c) 2019, Google Inc.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
package runner
import (
"bytes"
"encoding/binary"
"fmt"
"io"
"net"
)
type encryptionLevel byte
const (
encryptionInitial encryptionLevel = 0
encryptionEarlyData encryptionLevel = 1
encryptionHandshake encryptionLevel = 2
encryptionApplication encryptionLevel = 3
)
func (e encryptionLevel) String() string {
switch e {
case encryptionInitial:
return "initial"
case encryptionEarlyData:
return "early data"
case encryptionHandshake:
return "handshake"
case encryptionApplication:
return "application"
}
return fmt.Sprintf("unknown level (%d)", e)
}
// mockQUICTransport provides a record layer for sending/receiving messages
// when testing TLS over QUIC. It is only intended for testing, as it runs over
// an in-order reliable transport, looks nothing like the QUIC wire image, and
// provides no confidentiality guarantees. (In fact, it leaks keys in the
// clear.)
//
// Messages from TLS that are sent over a mockQUICTransport are a series of
// records in the following format:
//
// enum {
// initial(0), early_data(1), handshake(2), application(3), (255)
// } EncryptionLevel;
//
// struct {
// ContentType record_type;
// EncryptionLevel level;
// CipherSuite cipher_suite;
// opaque encrypted_record<0..2^32-1>;
// } MockQUICRecord;
//
// The "encrypted" record is the concatenation of the encryption key and
// plaintext. It and the cipher suite exist only to check both sides agree on
// encryption parameters. The key is included in the length prefix so records
// may be skipped without knowing the key length.
type mockQUICTransport struct {
net.Conn
readLevel, writeLevel encryptionLevel
readSecret, writeSecret []byte
readCipherSuite, writeCipherSuite uint16
skipEarlyData bool
}
func newMockQUICTransport(conn net.Conn) *mockQUICTransport {
return &mockQUICTransport{Conn: conn}
}
func (m *mockQUICTransport) read() (recordType, []byte, error) {
for {
header := make([]byte, 8)
if _, err := io.ReadFull(m.Conn, header); err != nil {
return 0, nil, err
}
typ := recordType(header[0])
level := encryptionLevel(header[1])
cipherSuite := binary.BigEndian.Uint16(header[2:4])
length := binary.BigEndian.Uint32(header[4:])
value := make([]byte, length)
if _, err := io.ReadFull(m.Conn, value); err != nil {
return 0, nil, fmt.Errorf("error reading record")
}
if level != m.readLevel {
if m.skipEarlyData && level == encryptionEarlyData {
continue
}
return 0, nil, fmt.Errorf("received record at %s encryption level, but expected %s", level, m.readLevel)
}
if cipherSuite != m.readCipherSuite {
return 0, nil, fmt.Errorf("received cipher suite %d does not match expected %d", cipherSuite, m.readCipherSuite)
}
if len(m.readSecret) > len(value) {
return 0, nil, fmt.Errorf("input length too short")
}
secret := value[:len(m.readSecret)]
out := value[len(m.readSecret):]
if !bytes.Equal(secret, m.readSecret) {
return 0, nil, fmt.Errorf("secrets don't match: got %x but expected %x", secret, m.readSecret)
}
// Although not true for QUIC in general, our transport is ordered, so
// we expect to stop skipping early data after a valid record.
m.skipEarlyData = false
return typ, out, nil
}
}
func (m *mockQUICTransport) readRecord(want recordType) (recordType, []byte, error) {
return m.read()
}
func (m *mockQUICTransport) writeRecord(typ recordType, data []byte) (int, error) {
if typ != recordTypeApplicationData && typ != recordTypeHandshake {
return 0, fmt.Errorf("unsupported record type %d\n", typ)
}
length := len(m.writeSecret) + len(data)
payload := make([]byte, 1+1+2+4+length)
payload[0] = byte(typ)
payload[1] = byte(m.writeLevel)
binary.BigEndian.PutUint16(payload[2:4], m.writeCipherSuite)
binary.BigEndian.PutUint32(payload[4:8], uint32(length))
copy(payload[8:], m.writeSecret)
copy(payload[8+len(m.writeSecret):], data)
if _, err := m.Conn.Write(payload); err != nil {
return 0, err
}
return len(data), nil
}
func (m *mockQUICTransport) Write(b []byte) (int, error) {
panic("unexpected call to Write")
}
func (m *mockQUICTransport) Read(b []byte) (int, error) {
panic("unexpected call to Read")
}