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authorFelix Lange <fjl@twurst.com>2014-12-09 17:44:48 +0800
committerFelix Lange <fjl@twurst.com>2014-12-09 17:58:46 +0800
commitc084a7daa58117f1864eac5130ccf3290372fd4c (patch)
tree4785d96615e278e96b18f94a7b032c34ae5db64c /rlp/decode.go
parent93e858f88ef9a9a572c2dabd4aef8bbbd678dd97 (diff)
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rlp: fix panic in decodeList on go 1.4+
The documentation for reflect.Value.Index states that it will panic for out-of-bounds indices. Since go 1.4, it actually panics.
Diffstat (limited to 'rlp/decode.go')
-rw-r--r--rlp/decode.go109
1 files changed, 61 insertions, 48 deletions
diff --git a/rlp/decode.go b/rlp/decode.go
index 31485ee70..66830b89c 100644
--- a/rlp/decode.go
+++ b/rlp/decode.go
@@ -154,8 +154,6 @@ func decodeBigInt(s *Stream, val reflect.Value) error {
return nil
}
-const maxInt = int(^uint(0) >> 1)
-
func makeListDecoder(typ reflect.Type) (decoder, error) {
etype := typ.Elem()
if etype.Kind() == reflect.Uint8 && !reflect.PtrTo(etype).Implements(decoderInterface) {
@@ -169,55 +167,41 @@ func makeListDecoder(typ reflect.Type) (decoder, error) {
if err != nil {
return nil, err
}
- var maxLen = maxInt
+
if typ.Kind() == reflect.Array {
- maxLen = typ.Len()
- }
- dec := func(s *Stream, val reflect.Value) error {
- return decodeList(s, val, etypeinfo.decoder, maxLen)
+ return func(s *Stream, val reflect.Value) error {
+ return decodeListArray(s, val, etypeinfo.decoder)
+ }, nil
}
- return dec, nil
+ return func(s *Stream, val reflect.Value) error {
+ return decodeListSlice(s, val, etypeinfo.decoder)
+ }, nil
}
-// decodeList decodes RLP list elements into slices and arrays.
-//
-// The approach here is stolen from package json, although we differ
-// in the semantics for arrays. package json discards remaining
-// elements that would not fit into the array. We generate an error in
-// this case because we'd be losing information.
-func decodeList(s *Stream, val reflect.Value, elemdec decoder, maxelem int) error {
+func decodeListSlice(s *Stream, val reflect.Value, elemdec decoder) error {
size, err := s.List()
if err != nil {
return err
}
if size == 0 {
- if val.Kind() == reflect.Slice {
- val.Set(reflect.MakeSlice(val.Type(), 0, 0))
- } else {
- zero(val, 0)
- }
+ val.Set(reflect.MakeSlice(val.Type(), 0, 0))
return s.ListEnd()
}
i := 0
- for {
- if i > maxelem {
- return decodeError{"input list has too many elements", val.Type()}
- }
- if val.Kind() == reflect.Slice {
- // grow slice if necessary
- if i >= val.Cap() {
- newcap := val.Cap() + val.Cap()/2
- if newcap < 4 {
- newcap = 4
- }
- newv := reflect.MakeSlice(val.Type(), val.Len(), newcap)
- reflect.Copy(newv, val)
- val.Set(newv)
- }
- if i >= val.Len() {
- val.SetLen(i + 1)
+ for ; ; i++ {
+ // grow slice if necessary
+ if i >= val.Cap() {
+ newcap := val.Cap() + val.Cap()/2
+ if newcap < 4 {
+ newcap = 4
}
+ newv := reflect.MakeSlice(val.Type(), val.Len(), newcap)
+ reflect.Copy(newv, val)
+ val.Set(newv)
+ }
+ if i >= val.Len() {
+ val.SetLen(i + 1)
}
// decode into element
if err := elemdec(s, val.Index(i)); err == EOL {
@@ -225,26 +209,54 @@ func decodeList(s *Stream, val reflect.Value, elemdec decoder, maxelem int) erro
} else if err != nil {
return err
}
- i++
}
if i < val.Len() {
- if val.Kind() == reflect.Array {
- // zero the rest of the array.
- zero(val, i)
- } else {
- val.SetLen(i)
- }
+ val.SetLen(i)
}
return s.ListEnd()
}
+func decodeListArray(s *Stream, val reflect.Value, elemdec decoder) error {
+ size, err := s.List()
+ if err != nil {
+ return err
+ }
+ if size == 0 {
+ zero(val, 0)
+ return s.ListEnd()
+ }
+
+ // The approach here is stolen from package json, although we differ
+ // in the semantics for arrays. package json discards remaining
+ // elements that would not fit into the array. We generate an error in
+ // this case because we'd be losing information.
+ vlen := val.Len()
+ i := 0
+ for ; i < vlen; i++ {
+ if err := elemdec(s, val.Index(i)); err == EOL {
+ break
+ } else if err != nil {
+ return err
+ }
+ if i == vlen {
+ }
+ }
+ if i < vlen {
+ zero(val, i)
+ }
+ if err = s.ListEnd(); err == errNotAtEOL {
+ return decodeError{"input list has too many elements", val.Type()}
+ }
+ return err
+}
+
func decodeByteSlice(s *Stream, val reflect.Value) error {
kind, _, err := s.Kind()
if err != nil {
return err
}
if kind == List {
- return decodeList(s, val, decodeUint, maxInt)
+ return decodeListSlice(s, val, decodeUint)
}
b, err := s.Bytes()
if err == nil {
@@ -276,14 +288,15 @@ func decodeByteArray(s *Stream, val reflect.Value) error {
}
zero(val, int(size))
case List:
- return decodeList(s, val, decodeUint, val.Len())
+ return decodeListArray(s, val, decodeUint)
}
return nil
}
func zero(val reflect.Value, start int) {
z := reflect.Zero(val.Type().Elem())
- for i := start; i < val.Len(); i++ {
+ end := val.Len()
+ for i := start; i < end; i++ {
val.Index(i).Set(z)
}
}
@@ -358,7 +371,7 @@ func decodeInterface(s *Stream, val reflect.Value) error {
}
if kind == List {
slice := reflect.New(ifsliceType).Elem()
- if err := decodeList(s, slice, decodeInterface, maxInt); err != nil {
+ if err := decodeListSlice(s, slice, decodeInterface); err != nil {
return err
}
val.Set(slice)