diff options
| -rw-r--r-- | src/encoding/gob/decode.go | 19 | ||||
| -rw-r--r-- | src/encoding/gob/gobencdec_test.go | 24 |
2 files changed, 36 insertions, 7 deletions
diff --git a/src/encoding/gob/decode.go b/src/encoding/gob/decode.go index d2f6c749b1..0e0ec75ccc 100644 --- a/src/encoding/gob/decode.go +++ b/src/encoding/gob/decode.go @@ -871,8 +871,13 @@ func (dec *Decoder) decOpFor(wireId typeId, rt reflect.Type, name string, inProg return &op } +var maxIgnoreNestingDepth = 10000 + // decIgnoreOpFor returns the decoding op for a field that has no destination. -func (dec *Decoder) decIgnoreOpFor(wireId typeId, inProgress map[typeId]*decOp) *decOp { +func (dec *Decoder) decIgnoreOpFor(wireId typeId, inProgress map[typeId]*decOp, depth int) *decOp { + if depth > maxIgnoreNestingDepth { + error_(errors.New("invalid nesting depth")) + } // If this type is already in progress, it's a recursive type (e.g. map[string]*T). // Return the pointer to the op we're already building. if opPtr := inProgress[wireId]; opPtr != nil { @@ -896,7 +901,7 @@ func (dec *Decoder) decIgnoreOpFor(wireId typeId, inProgress map[typeId]*decOp) errorf("bad data: undefined type %s", wireId.string()) case wire.ArrayT != nil: elemId := wire.ArrayT.Elem - elemOp := dec.decIgnoreOpFor(elemId, inProgress) + elemOp := dec.decIgnoreOpFor(elemId, inProgress, depth+1) op = func(i *decInstr, state *decoderState, value reflect.Value) { state.dec.ignoreArray(state, *elemOp, wire.ArrayT.Len) } @@ -904,15 +909,15 @@ func (dec *Decoder) decIgnoreOpFor(wireId typeId, inProgress map[typeId]*decOp) case wire.MapT != nil: keyId := dec.wireType[wireId].MapT.Key elemId := dec.wireType[wireId].MapT.Elem - keyOp := dec.decIgnoreOpFor(keyId, inProgress) - elemOp := dec.decIgnoreOpFor(elemId, inProgress) + keyOp := dec.decIgnoreOpFor(keyId, inProgress, depth+1) + elemOp := dec.decIgnoreOpFor(elemId, inProgress, depth+1) op = func(i *decInstr, state *decoderState, value reflect.Value) { state.dec.ignoreMap(state, *keyOp, *elemOp) } case wire.SliceT != nil: elemId := wire.SliceT.Elem - elemOp := dec.decIgnoreOpFor(elemId, inProgress) + elemOp := dec.decIgnoreOpFor(elemId, inProgress, depth+1) op = func(i *decInstr, state *decoderState, value reflect.Value) { state.dec.ignoreSlice(state, *elemOp) } @@ -1073,7 +1078,7 @@ func (dec *Decoder) compileSingle(remoteId typeId, ut *userTypeInfo) (engine *de func (dec *Decoder) compileIgnoreSingle(remoteId typeId) *decEngine { engine := new(decEngine) engine.instr = make([]decInstr, 1) // one item - op := dec.decIgnoreOpFor(remoteId, make(map[typeId]*decOp)) + op := dec.decIgnoreOpFor(remoteId, make(map[typeId]*decOp), 0) ovfl := overflow(dec.typeString(remoteId)) engine.instr[0] = decInstr{*op, 0, nil, ovfl} engine.numInstr = 1 @@ -1118,7 +1123,7 @@ func (dec *Decoder) compileDec(remoteId typeId, ut *userTypeInfo) (engine *decEn localField, present := srt.FieldByName(wireField.Name) // TODO(r): anonymous names if !present || !isExported(wireField.Name) { - op := dec.decIgnoreOpFor(wireField.Id, make(map[typeId]*decOp)) + op := dec.decIgnoreOpFor(wireField.Id, make(map[typeId]*decOp), 0) engine.instr[fieldnum] = decInstr{*op, fieldnum, nil, ovfl} continue } diff --git a/src/encoding/gob/gobencdec_test.go b/src/encoding/gob/gobencdec_test.go index 6d2c8db42d..1b52ecc6c8 100644 --- a/src/encoding/gob/gobencdec_test.go +++ b/src/encoding/gob/gobencdec_test.go @@ -12,6 +12,7 @@ import ( "fmt" "io" "net" + "reflect" "strings" "testing" "time" @@ -796,3 +797,26 @@ func TestNetIP(t *testing.T) { t.Errorf("decoded to %v, want 1.2.3.4", ip.String()) } } + +func TestIngoreDepthLimit(t *testing.T) { + // We don't test the actual depth limit because it requires building an + // extremely large message, which takes quite a while. + oldNestingDepth := maxIgnoreNestingDepth + maxIgnoreNestingDepth = 100 + defer func() { maxIgnoreNestingDepth = oldNestingDepth }() + b := new(bytes.Buffer) + enc := NewEncoder(b) + typ := reflect.TypeOf(int(0)) + nested := reflect.ArrayOf(1, typ) + for i := 0; i < 100; i++ { + nested = reflect.ArrayOf(1, nested) + } + badStruct := reflect.New(reflect.StructOf([]reflect.StructField{{Name: "F", Type: nested}})) + enc.Encode(badStruct.Interface()) + dec := NewDecoder(b) + var output struct{ Hello int } + expectedErr := "invalid nesting depth" + if err := dec.Decode(&output); err == nil || err.Error() != expectedErr { + t.Errorf("Decode didn't fail with depth limit of 100: want %q, got %q", expectedErr, err) + } +} |