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fix: avoid memory errors by handling frame indirections (#739)

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In all situations where the results are set directly
to the frame, and not using a value helper, the right level of
indirections must be applied, otherwise we may end-up writing
in the wrong frame (the local one, instead of a caller or global).

Fixes #735.
This commit is contained in:
Marc Vertes
2020-07-03 11:02:46 +02:00
committed by GitHub
parent 4058fd8c44
commit 2f2df7a0f8
3 changed files with 134 additions and 47 deletions
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134
interp/run.go
View File

@@ -510,19 +510,21 @@ func deref(n *node) {
value := genValue(n.child[0])
tnext := getExec(n.tnext)
i := n.findex
l := n.level
if n.fnext != nil {
fnext := getExec(n.fnext)
n.exec = func(f *frame) bltn {
f.data[i] = value(f).Elem()
if f.data[i].Bool() {
r := value(f).Elem()
if r.Bool() {
getFrame(f, l).data[i] = r
return tnext
}
return fnext
}
} else {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).Elem()
getFrame(f, l).data[i] = value(f).Elem()
return tnext
}
}
@@ -858,9 +860,10 @@ func call(n *node) {
}
default:
// Multiple return values frame index are indexed from the node frame index.
l := n.level
for i := range rtypes {
j := n.findex + i
rvalues[i] = func(f *frame) reflect.Value { return f.data[j] }
rvalues[i] = func(f *frame) reflect.Value { return getFrame(f, l).data[j] }
}
}
@@ -1012,6 +1015,21 @@ func pindex(i, variadic int) int {
return variadic
}
func getFrame(f *frame, l int) *frame {
switch l {
case 0:
return f
case 1:
return f.anc
case 2:
return f.anc.anc
}
for ; l > 0; l-- {
f = f.anc
}
return f
}
// Callbin calls a function from a bin import, accessible through reflect.
func callBin(n *node) {
tnext := getExec(n.tnext)
@@ -1112,6 +1130,7 @@ func callBin(n *node) {
case fnext != nil:
// Handle branching according to boolean result.
index := n.findex
level := n.level
n.exec = func(f *frame) bltn {
in := make([]reflect.Value, l)
for i, v := range values {
@@ -1119,7 +1138,7 @@ func callBin(n *node) {
}
res := callFn(value(f), in)
b := res[0].Bool()
f.data[index].SetBool(b)
getFrame(f, level).data[index].SetBool(b)
if b {
return tnext
}
@@ -1175,7 +1194,7 @@ func callBin(n *node) {
}
out := callFn(value(f), in)
for i := 0; i < len(out); i++ {
f.data[n.findex+i].Set(out[i])
getFrame(f, n.level).data[n.findex+i].Set(out[i])
}
return tnext
}
@@ -1186,6 +1205,7 @@ func callBin(n *node) {
func getIndexBinMethod(n *node) {
// dest := genValue(n)
i := n.findex
l := n.level
m := n.val.(int)
value := genValue(n.child[0])
next := getExec(n.tnext)
@@ -1193,20 +1213,21 @@ func getIndexBinMethod(n *node) {
n.exec = func(f *frame) bltn {
// Can not use .Set() because dest type contains the receiver and source not
// dest(f).Set(value(f).Method(m))
f.data[i] = value(f).Method(m)
getFrame(f, l).data[i] = value(f).Method(m)
return next
}
}
func getIndexBinPtrMethod(n *node) {
i := n.findex
l := n.level
m := n.val.(int)
value := genValue(n.child[0])
next := getExec(n.tnext)
n.exec = func(f *frame) bltn {
// Can not use .Set() because dest type contains the receiver and source not
f.data[i] = value(f).Addr().Method(m)
getFrame(f, l).data[i] = value(f).Addr().Method(m)
return next
}
}
@@ -1216,21 +1237,23 @@ func getIndexArray(n *node) {
tnext := getExec(n.tnext)
value0 := genValueArray(n.child[0]) // array
i := n.findex
l := n.level
if n.child[1].rval.IsValid() { // constant array index
ai := int(vInt(n.child[1].rval))
if n.fnext != nil {
fnext := getExec(n.fnext)
n.exec = func(f *frame) bltn {
f.data[i] = value0(f).Index(ai)
if f.data[i].Bool() {
r := value0(f).Index(ai)
getFrame(f, l).data[i] = r
if r.Bool() {
return tnext
}
return fnext
}
} else {
n.exec = func(f *frame) bltn {
f.data[i] = value0(f).Index(ai)
getFrame(f, l).data[i] = value0(f).Index(ai)
return tnext
}
}
@@ -1241,8 +1264,9 @@ func getIndexArray(n *node) {
fnext := getExec(n.fnext)
n.exec = func(f *frame) bltn {
_, vi := value1(f)
f.data[i] = value0(f).Index(int(vi))
if f.data[i].Bool() {
r := value0(f).Index(int(vi))
getFrame(f, l).data[i] = r
if r.Bool() {
return tnext
}
return fnext
@@ -1250,7 +1274,7 @@ func getIndexArray(n *node) {
} else {
n.exec = func(f *frame) bltn {
_, vi := value1(f)
f.data[i] = value0(f).Index(int(vi))
getFrame(f, l).data[i] = value0(f).Index(int(vi))
return tnext
}
}
@@ -1453,6 +1477,7 @@ func getFunc(n *node) {
func getMethod(n *node) {
i := n.findex
l := n.level
next := getExec(n.tnext)
n.exec = func(f *frame) bltn {
@@ -1461,7 +1486,7 @@ func getMethod(n *node) {
nod.val = &nod
nod.recv = n.recv
nod.frame = fr
f.data[i] = reflect.ValueOf(&nod)
getFrame(f, l).data[i] = reflect.ValueOf(&nod)
return next
}
}
@@ -1471,6 +1496,7 @@ func getMethodByName(n *node) {
value0 := genValue(n.child[0])
name := n.child[1].ident
i := n.findex
l := n.level
n.exec = func(f *frame) bltn {
val := value0(f).Interface().(valueInterface)
@@ -1480,7 +1506,7 @@ func getMethodByName(n *node) {
nod.val = &nod
nod.recv = &receiver{nil, val.value, li}
nod.frame = fr
f.data[i] = reflect.ValueOf(&nod)
getFrame(f, l).data[i] = reflect.ValueOf(&nod)
return next
}
}
@@ -1490,6 +1516,7 @@ func getIndexSeq(n *node) {
index := n.val.([]int)
tnext := getExec(n.tnext)
i := n.findex
l := n.level
// Note:
// Here we have to store the result using
@@ -1508,8 +1535,9 @@ func getIndexSeq(n *node) {
if v.Type().Kind() == reflect.Interface && n.child[0].typ.recursive {
v = writableDeref(v)
}
f.data[i] = v.FieldByIndex(index)
if f.data[i].Bool() {
r := v.FieldByIndex(index)
getFrame(f, l).data[i] = r
if r.Bool() {
return tnext
}
return fnext
@@ -1520,7 +1548,7 @@ func getIndexSeq(n *node) {
if v.Type().Kind() == reflect.Interface && n.child[0].typ.recursive {
v = writableDeref(v)
}
f.data[i] = v.FieldByIndex(index)
getFrame(f, l).data[i] = v.FieldByIndex(index)
return tnext
}
}
@@ -1545,19 +1573,21 @@ func getPtrIndexSeq(n *node) {
value = genValue(n.child[0])
}
i := n.findex
l := n.level
if n.fnext != nil {
fnext := getExec(n.fnext)
n.exec = func(f *frame) bltn {
f.data[i] = value(f).Elem().FieldByIndex(index)
if f.data[i].Bool() {
r := value(f).Elem().FieldByIndex(index)
getFrame(f, l).data[i] = r
if r.Bool() {
return tnext
}
return fnext
}
} else {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).Elem().FieldByIndex(index)
getFrame(f, l).data[i] = value(f).Elem().FieldByIndex(index)
return tnext
}
}
@@ -1567,22 +1597,25 @@ func getIndexSeqField(n *node) {
value := genValue(n.child[0])
index := n.val.([]int)
i := n.findex
l := n.level
tnext := getExec(n.tnext)
if n.fnext != nil {
fnext := getExec(n.fnext)
if n.child[0].typ.TypeOf().Kind() == reflect.Ptr {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).Elem().FieldByIndex(index)
if f.data[i].Bool() {
r := value(f).Elem().FieldByIndex(index)
getFrame(f, l).data[i] = r
if r.Bool() {
return tnext
}
return fnext
}
} else {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).FieldByIndex(index)
if f.data[i].Bool() {
r := value(f).FieldByIndex(index)
getFrame(f, l).data[i] = r
if r.Bool() {
return tnext
}
return fnext
@@ -1591,12 +1624,12 @@ func getIndexSeqField(n *node) {
} else {
if n.child[0].typ.TypeOf().Kind() == reflect.Ptr {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).Elem().FieldByIndex(index)
getFrame(f, l).data[i] = value(f).Elem().FieldByIndex(index)
return tnext
}
} else {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).FieldByIndex(index)
getFrame(f, l).data[i] = value(f).FieldByIndex(index)
return tnext
}
}
@@ -1609,16 +1642,17 @@ func getIndexSeqPtrMethod(n *node) {
fi := index[1:]
mi := index[0]
i := n.findex
l := n.level
next := getExec(n.tnext)
if n.child[0].typ.TypeOf().Kind() == reflect.Ptr {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).Elem().FieldByIndex(fi).Addr().Method(mi)
getFrame(f, l).data[i] = value(f).Elem().FieldByIndex(fi).Addr().Method(mi)
return next
}
} else {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).FieldByIndex(fi).Addr().Method(mi)
getFrame(f, l).data[i] = value(f).FieldByIndex(fi).Addr().Method(mi)
return next
}
}
@@ -1630,16 +1664,17 @@ func getIndexSeqMethod(n *node) {
fi := index[1:]
mi := index[0]
i := n.findex
l := n.level
next := getExec(n.tnext)
if n.child[0].typ.TypeOf().Kind() == reflect.Ptr {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).Elem().FieldByIndex(fi).Method(mi)
getFrame(f, l).data[i] = value(f).Elem().FieldByIndex(fi).Method(mi)
return next
}
} else {
n.exec = func(f *frame) bltn {
f.data[i] = value(f).FieldByIndex(fi).Method(mi)
getFrame(f, l).data[i] = value(f).FieldByIndex(fi).Method(mi)
return next
}
}
@@ -2017,6 +2052,7 @@ func doCompositeLit(n *node, hasType bool) {
}
i := n.findex
l := n.level
n.exec = func(f *frame) bltn {
a := reflect.New(n.typ.TypeOf()).Elem()
for i, v := range values {
@@ -2028,7 +2064,7 @@ func doCompositeLit(n *node, hasType bool) {
case destInterface:
d.Set(reflect.ValueOf(valueInterface{n, a}))
default:
f.data[i] = a
getFrame(f, l).data[i] = a
}
return next
}
@@ -2609,6 +2645,7 @@ func recv(n *node) {
value := genValue(n.child[0])
tnext := getExec(n.tnext)
i := n.findex
l := n.level
if n.interp.cancelChan {
// Cancellable channel read
@@ -2616,10 +2653,10 @@ func recv(n *node) {
fnext := getExec(n.fnext)
n.exec = func(f *frame) bltn {
// Fast: channel read doesn't block
var ok bool
ch := value(f)
if f.data[i], ok = ch.TryRecv(); ok {
if f.data[i].Bool() {
if r, ok := ch.TryRecv(); ok {
getFrame(f, l).data[i] = r
if r.Bool() {
return tnext
}
return fnext
@@ -2637,14 +2674,14 @@ func recv(n *node) {
} else {
n.exec = func(f *frame) bltn {
// Fast: channel read doesn't block
var ok bool
ch := value(f)
if f.data[i], ok = ch.TryRecv(); ok {
if r, ok := ch.TryRecv(); ok {
getFrame(f, l).data[i] = r
return tnext
}
// Slow: channel is blocked, allow cancel
var chosen int
chosen, f.data[i], _ = reflect.Select([]reflect.SelectCase{f.done, {Dir: reflect.SelectRecv, Chan: ch}})
chosen, getFrame(f, l).data[i], _ = reflect.Select([]reflect.SelectCase{f.done, {Dir: reflect.SelectRecv, Chan: ch}})
if chosen == 0 {
return nil
}
@@ -2656,7 +2693,8 @@ func recv(n *node) {
if n.fnext != nil {
fnext := getExec(n.fnext)
n.exec = func(f *frame) bltn {
if f.data[i], _ = value(f).Recv(); f.data[i].Bool() {
if r, _ := value(f).Recv(); r.Bool() {
getFrame(f, l).data[i] = r
return tnext
}
return fnext
@@ -2664,7 +2702,7 @@ func recv(n *node) {
} else {
i := n.findex
n.exec = func(f *frame) bltn {
f.data[i], _ = value(f).Recv()
getFrame(f, l).data[i], _ = value(f).Recv()
return tnext
}
}
@@ -2945,6 +2983,7 @@ func _select(n *node) {
// slice expression: array[low:high:max].
func slice(n *node) {
i := n.findex
l := n.level
next := getExec(n.tnext)
value0 := genValueArray(n.child[0]) // array
value1 := genValue(n.child[1]) // low (if 2 or 3 args) or high (if 1 arg)
@@ -2953,7 +2992,7 @@ func slice(n *node) {
case 2:
n.exec = func(f *frame) bltn {
a := value0(f)
f.data[i] = a.Slice(int(value1(f).Int()), a.Len())
getFrame(f, l).data[i] = a.Slice(int(value1(f).Int()), a.Len())
return next
}
case 3:
@@ -2961,7 +3000,7 @@ func slice(n *node) {
n.exec = func(f *frame) bltn {
a := value0(f)
f.data[i] = a.Slice(int(value1(f).Int()), int(value2(f).Int()))
getFrame(f, l).data[i] = a.Slice(int(value1(f).Int()), int(value2(f).Int()))
return next
}
case 4:
@@ -2970,7 +3009,7 @@ func slice(n *node) {
n.exec = func(f *frame) bltn {
a := value0(f)
f.data[i] = a.Slice3(int(value1(f).Int()), int(value2(f).Int()), int(value3(f).Int()))
getFrame(f, l).data[i] = a.Slice3(int(value1(f).Int()), int(value2(f).Int()), int(value3(f).Int()))
return next
}
}
@@ -2979,6 +3018,7 @@ func slice(n *node) {
// slice expression, no low value: array[:high:max].
func slice0(n *node) {
i := n.findex
l := n.level
next := getExec(n.tnext)
value0 := genValueArray(n.child[0])
@@ -2986,14 +3026,14 @@ func slice0(n *node) {
case 1:
n.exec = func(f *frame) bltn {
a := value0(f)
f.data[i] = a.Slice(0, a.Len())
getFrame(f, l).data[i] = a.Slice(0, a.Len())
return next
}
case 2:
value1 := genValue(n.child[1])
n.exec = func(f *frame) bltn {
a := value0(f)
f.data[i] = a.Slice(0, int(value1(f).Int()))
getFrame(f, l).data[i] = a.Slice(0, int(value1(f).Int()))
return next
}
case 3:
@@ -3001,7 +3041,7 @@ func slice0(n *node) {
value2 := genValue(n.child[2])
n.exec = func(f *frame) bltn {
a := value0(f)
f.data[i] = a.Slice3(0, int(value1(f).Int()), int(value2(f).Int()))
getFrame(f, l).data[i] = a.Slice3(0, int(value1(f).Int()), int(value2(f).Int()))
return next
}
}