// TestVarStringOverflowErrors performs tests to ensure deserializing variable
// length strings intentionally crafted to use large values for the string
// length are handled properly. This could otherwise potentially be used as an
// attack vector.
func TestVarStringOverflowErrors(t *testing.T) {
pver := btcwire.ProtocolVersion
tests := []struct {
buf []byte // Wire encoding
pver uint32 // Protocol version for wire encoding
err error // Expected error
}{
{[]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
pver, &btcwire.MessageError{}},
{[]byte{0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01},
pver, &btcwire.MessageError{}},
}
t.Logf("Running %d tests", len(tests))
for i, test := range tests {
// Decode from wire format.
rbuf := bytes.NewBuffer(test.buf)
_, err := btcwire.TstReadVarString(rbuf, test.pver)
if reflect.TypeOf(err) != reflect.TypeOf(test.err) {
t.Errorf("readVarString #%d wrong error got: %v, "+
"want: %v", i, err, reflect.TypeOf(test.err))
continue
}
}
}
// TestVarStringWire tests wire encode and decode for variable length strings.
func TestVarStringWire(t *testing.T) {
pver := btcwire.ProtocolVersion
// str256 is a string that takes a 2-byte varint to encode.
str256 := strings.Repeat("test", 64)
tests := []struct {
in string // String to encode
out string // String to decoded value
buf []byte // Wire encoding
pver uint32 // Protocol version for wire encoding
}{
// Latest protocol version.
// Empty string
{"", "", []byte{0x00}, pver},
// Single byte varint + string
{"Test", "Test", append([]byte{0x04}, []byte("Test")...), pver},
// 2-byte varint + string
{str256, str256, append([]byte{0xfd, 0x00, 0x01}, []byte(str256)...), pver},
}
t.Logf("Running %d tests", len(tests))
for i, test := range tests {
// Encode to wire format.
var buf bytes.Buffer
err := btcwire.TstWriteVarString(&buf, test.pver, test.in)
if err != nil {
t.Errorf("writeVarString #%d error %v", i, err)
continue
}
if !bytes.Equal(buf.Bytes(), test.buf) {
t.Errorf("writeVarString #%d\n got: %s want: %s", i,
spew.Sdump(buf.Bytes()), spew.Sdump(test.buf))
continue
}
// Decode from wire format.
rbuf := bytes.NewBuffer(test.buf)
val, err := btcwire.TstReadVarString(rbuf, test.pver)
if err != nil {
t.Errorf("readVarString #%d error %v", i, err)
continue
}
if val != test.out {
t.Errorf("readVarString #%d\n got: %d want: %d", i,
val, test.out)
continue
}
}
}
// TestVarStringWireErrors performs negative tests against wire encode and
// decode of variable length strings to confirm error paths work correctly.
func TestVarStringWireErrors(t *testing.T) {
pver := btcwire.ProtocolVersion
// str256 is a string that takes a 2-byte varint to encode.
str256 := strings.Repeat("test", 64)
tests := []struct {
in string // Value to encode
buf []byte // Wire encoding
pver uint32 // Protocol version for wire encoding
max int // Max size of fixed buffer to induce errors
writeErr error // Expected write error
readErr error // Expected read error
}{
// Latest protocol version with intentional read/write errors.
// Force errors on empty string.
{"", []byte{0x00}, pver, 0, io.ErrShortWrite, io.EOF},
// Force error on single byte varint + string.
{"Test", []byte{0x04}, pver, 2, io.ErrShortWrite, io.ErrUnexpectedEOF},
// Force errors on 2-byte varint + string.
{str256, []byte{0xfd}, pver, 2, io.ErrShortWrite, io.ErrUnexpectedEOF},
}
t.Logf("Running %d tests", len(tests))
for i, test := range tests {
// Encode to wire format.
w := newFixedWriter(test.max)
err := btcwire.TstWriteVarString(w, test.pver, test.in)
if err != test.writeErr {
t.Errorf("writeVarString #%d wrong error got: %v, want: %v",
i, err, test.writeErr)
continue
}
// Decode from wire format.
r := newFixedReader(test.max, test.buf)
_, err = btcwire.TstReadVarString(r, test.pver)
if err != test.readErr {
t.Errorf("readVarString #%d wrong error got: %v, want: %v",
i, err, test.readErr)
continue
}
}
}
// BenchmarkReadVarStr10 performs a benchmark on how long it takes to read a
// ten byte variable length string.
func BenchmarkReadVarStr10(b *testing.B) {
buf := []byte{0x0a, 't', 'e', 's', 't', '0', '1', '2', '3', '4', '5'}
for i := 0; i < b.N; i++ {
btcwire.TstReadVarString(bytes.NewBuffer(buf), 0)
}
}
// BenchmarkReadVarStr4 performs a benchmark on how long it takes to read a
// four byte variable length string.
func BenchmarkReadVarStr4(b *testing.B) {
buf := []byte{0x04, 't', 'e', 's', 't'}
for i := 0; i < b.N; i++ {
btcwire.TstReadVarString(bytes.NewBuffer(buf), 0)
}
}