From 4d5a518a0ba7b0f1d42c73f3c28fe0828e7ea974 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Fri, 17 Apr 2015 02:01:38 +0200
Subject: [PATCH] rlp: stop accepting lists for byte slices and byte arrays

---
 rlp/decode.go      | 14 +++-----------
 rlp/decode_test.go | 41 +++++++----------------------------------
 2 files changed, 10 insertions(+), 45 deletions(-)

diff --git a/rlp/decode.go b/rlp/decode.go
index 394f83fb23..97eacf64bc 100644
--- a/rlp/decode.go
+++ b/rlp/decode.go
@@ -58,9 +58,8 @@ type Decoder interface {
 //     }
 //
 // To decode into a slice, the input must be a list and the resulting
-// slice will contain the input elements in order.
-// As a special case, if the slice has a byte-size element type, the input
-// can also be an RLP string.
+// slice will contain the input elements in order. For byte slices,
+// the input must be an RLP string.
 //
 // To decode into a Go string, the input must be an RLP string. The
 // input bytes are taken as-is and will not necessarily be valid UTF-8.
@@ -309,13 +308,6 @@ func decodeListArray(s *Stream, val reflect.Value, elemdec decoder) error {
 }
 
 func decodeByteSlice(s *Stream, val reflect.Value) error {
-	kind, _, err := s.Kind()
-	if err != nil {
-		return err
-	}
-	if kind == List {
-		return decodeListSlice(s, val, decodeUint)
-	}
 	b, err := s.Bytes()
 	if err != nil {
 		return wrapStreamError(err, val.Type())
@@ -351,7 +343,7 @@ func decodeByteArray(s *Stream, val reflect.Value) error {
 			return wrapStreamError(ErrCanonSize, val.Type())
 		}
 	case List:
-		return decodeListArray(s, val, decodeUint)
+		return wrapStreamError(ErrExpectedString, val.Type())
 	}
 	return nil
 }
diff --git a/rlp/decode_test.go b/rlp/decode_test.go
index fd52bd1be1..0b69ff1f4c 100644
--- a/rlp/decode_test.go
+++ b/rlp/decode_test.go
@@ -323,56 +323,29 @@ var decodeTests = []decodeTest{
 	// byte slices
 	{input: "01", ptr: new([]byte), value: []byte{1}},
 	{input: "80", ptr: new([]byte), value: []byte{}},
-
 	{input: "8D6162636465666768696A6B6C6D", ptr: new([]byte), value: []byte("abcdefghijklm")},
-	{input: "C0", ptr: new([]byte), value: []byte{}},
-	{input: "C3010203", ptr: new([]byte), value: []byte{1, 2, 3}},
-
-	{
-		input: "8105",
-		ptr:   new([]byte),
-		error: "rlp: non-canonical size information for []uint8",
-	},
-	{
-		input: "C3820102",
-		ptr:   new([]byte),
-		error: "rlp: input string too long for uint8, decoding into ([]uint8)[0]",
-	},
+	{input: "C0", ptr: new([]byte), error: "rlp: expected input string or byte for []uint8"},
+	{input: "8105", ptr: new([]byte), error: "rlp: non-canonical size information for []uint8"},
 
 	// byte arrays
 	{input: "01", ptr: new([5]byte), value: [5]byte{1}},
 	{input: "80", ptr: new([5]byte), value: [5]byte{}},
 	{input: "850102030405", ptr: new([5]byte), value: [5]byte{1, 2, 3, 4, 5}},
-	{input: "C0", ptr: new([5]byte), value: [5]byte{}},
-	{input: "C3010203", ptr: new([5]byte), value: [5]byte{1, 2, 3, 0, 0}},
 
-	{
-		input: "C3820102",
-		ptr:   new([5]byte),
-		error: "rlp: input string too long for uint8, decoding into ([5]uint8)[0]",
-	},
-	{
-		input: "86010203040506",
-		ptr:   new([5]byte),
-		error: "rlp: input string too long for [5]uint8",
-	},
-	{
-		input: "8105",
-		ptr:   new([5]byte),
-		error: "rlp: non-canonical size information for [5]uint8",
-	},
+	// byte array errors
+	{input: "C0", ptr: new([5]byte), error: "rlp: expected input string or byte for [5]uint8"},
+	{input: "C3010203", ptr: new([5]byte), error: "rlp: expected input string or byte for [5]uint8"},
+	{input: "86010203040506", ptr: new([5]byte), error: "rlp: input string too long for [5]uint8"},
+	{input: "8105", ptr: new([5]byte), error: "rlp: non-canonical size information for [5]uint8"},
 
 	// byte array reuse (should be zeroed)
 	{input: "850102030405", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 4, 5}},
 	{input: "01", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: String
 	{input: "850102030405", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 4, 5}},
 	{input: "01", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: Byte
-	{input: "C3010203", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 0, 0}},
-	{input: "C101", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: List
 
 	// zero sized byte arrays
 	{input: "80", ptr: new([0]byte), value: [0]byte{}},
-	{input: "C0", ptr: new([0]byte), value: [0]byte{}},
 	{input: "01", ptr: new([0]byte), error: "rlp: input string too long for [0]uint8"},
 	{input: "8101", ptr: new([0]byte), error: "rlp: input string too long for [0]uint8"},