encoding/binary: make Read return an error when data is not a pointer

Make binary.Read return an error when passed `data` argument is not
a pointer to a fixed-size value or a slice of fixed-size values.

Fixes #32927

Change-Id: I04f48be55fe9b0cc66c983d152407d0e42cbcd95
Reviewed-on: https://go-review.googlesource.com/c/go/+/184957
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

2 files changed, 35 insertions, 1 deletions

diff --git a/src/encoding/binary/binary.go b/src/encoding/binary/binary.go
index 43fa821b83..33066fc77a 100644
--- a/src/encoding/binary/binary.go
+++ b/src/encoding/binary/binary.go
@@ -219,8 +219,12 @@ func Read(r io.Reader, order ByteOrder, data interface{}) error {
 			for i := range data {
 				data[i] = order.Uint64(bs[8*i:])
 			}
+		default:
+			n = 0 // fast path doesn't apply
+		}
+		if n != 0 {
+			return nil
 		}
-		return nil
 	}
 
 	// Fallback to reflect-based decoding.
diff --git a/src/encoding/binary/binary_test.go b/src/encoding/binary/binary_test.go
index d7ae23a60e..778de6908c 100644
--- a/src/encoding/binary/binary_test.go
+++ b/src/encoding/binary/binary_test.go
@@ -6,6 +6,7 @@ package binary
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"math"
@@ -451,6 +452,35 @@ func TestEarlyBoundsChecks(t *testing.T) {
 	}
 }
 
+func TestReadInvalidDestination(t *testing.T) {
+	testReadInvalidDestination(t, BigEndian)
+	testReadInvalidDestination(t, LittleEndian)
+}
+
+func testReadInvalidDestination(t *testing.T, order ByteOrder) {
+	destinations := []interface{}{
+		int8(0),
+		int16(0),
+		int32(0),
+		int64(0),
+
+		uint8(0),
+		uint16(0),
+		uint32(0),
+		uint64(0),
+
+		bool(false),
+	}
+
+	for _, dst := range destinations {
+		err := Read(bytes.NewReader([]byte{1, 2, 3, 4, 5, 6, 7, 8}), order, dst)
+		want := fmt.Sprintf("binary.Read: invalid type %T", dst)
+		if err == nil || err.Error() != want {
+			t.Fatalf("for type %T: got %q; want %q", dst, err, want)
+		}
+	}
+}
+
 type byteSliceReader struct {
 	remain []byte
 }