Add slice range checks to UnmarshalBinary() (#232)

* Add slice range checks to `UnmarshalBinary()`.
* Avoid use of `%w` verb with `Errorf()` for compatibility with older Go versions.
This commit is contained in:
James Harris 2021-06-23 08:24:56 +10:00 committed by GitHub
parent 501661573f
commit cc4584f0a5
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2 changed files with 29 additions and 1 deletions

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@ -1152,12 +1152,22 @@ func (d Decimal) MarshalJSON() ([]byte, error) {
// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface. As a string representation // UnmarshalBinary implements the encoding.BinaryUnmarshaler interface. As a string representation
// is already used when encoding to text, this method stores that string as []byte // is already used when encoding to text, this method stores that string as []byte
func (d *Decimal) UnmarshalBinary(data []byte) error { func (d *Decimal) UnmarshalBinary(data []byte) error {
// Verify we have at least 5 bytes, 4 for the exponent and at least 1 more
// for the GOB encoded value.
if len(data) < 5 {
return fmt.Errorf("error decoding binary %v: expected at least 5 bytes, got %d", data, len(data))
}
// Extract the exponent // Extract the exponent
d.exp = int32(binary.BigEndian.Uint32(data[:4])) d.exp = int32(binary.BigEndian.Uint32(data[:4]))
// Extract the value // Extract the value
d.value = new(big.Int) d.value = new(big.Int)
return d.value.GobDecode(data[4:]) if err := d.value.GobDecode(data[4:]); err != nil {
return fmt.Errorf("error decoding binary %v: %s", data, err)
}
return nil
} }
// MarshalBinary implements the encoding.BinaryMarshaler interface. // MarshalBinary implements the encoding.BinaryMarshaler interface.

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@ -2798,6 +2798,24 @@ func TestBinary(t *testing.T) {
} }
} }
func TestBinary_DataTooShort(t *testing.T) {
var d Decimal
err := d.UnmarshalBinary(nil) // nil slice has length 0
if err == nil {
t.Fatalf("expected error, got %v", d)
}
}
func TestBinary_InvalidValue(t *testing.T) {
var d Decimal
err := d.UnmarshalBinary([]byte{0, 0, 0, 0, 'x'}) // valid exponent, invalid value
if err == nil {
t.Fatalf("expected error, got %v", d)
}
}
func slicesEqual(a, b []byte) bool { func slicesEqual(a, b []byte) bool {
for i, val := range a { for i, val := range a {
if b[i] != val { if b[i] != val {