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x-pack/filebeat/input/internal/private: add global path redaction
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The original package was not designed to deal with values that could not
have sibling fields to mark privacy. This adds the capacity to redact
such types.
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@efd6
efd6 committed Sep 30, 2024
1 parent a628d62 commit ac8d34e
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Showing 2 changed files with 95 additions and 17 deletions.
55 changes: 39 additions & 16 deletions x-pack/filebeat/input/internal/private/private.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,12 +25,17 @@ var privateKey = reflect.ValueOf("private")
// used, falling back to the field name if not present. The tag parameter is
// ignored for map values.
//
// The global parameter indicates a set of dot-separated paths to redact. Paths
// originate at the root of val. If global is used, the resultin redaction is on
// the union of the fields redacted with tags and the fields redacted with the
// global paths.
//
// If a field has a `private:...` tag, its tag value will also be used to
// determine the list of private fields. If the private tag is empty,
// `private:""`, the fields with the tag will be marked as private. Otherwise
// the comma-separated list of names with be used. The list may refer to its
// own field.
func Redact[T any](val T, tag string) (redacted T, err error) {
func Redact[T any](val T, tag string, global []string) (redacted T, err error) {
defer func() {
switch r := recover().(type) {
case nil:
Expand All @@ -49,13 +54,13 @@ func Redact[T any](val T, tag string) (redacted T, err error) {
rv := reflect.ValueOf(val)
switch rv.Kind() {
case reflect.Map, reflect.Pointer, reflect.Struct:
return redact(rv, tag, 0, make(map[any]int)).Interface().(T), nil
return redact(rv, tag, slices.Clone(global), 0, make(map[any]int)).Interface().(T), nil
default:
return val, nil
}
}

func redact(v reflect.Value, tag string, depth int, seen map[any]int) reflect.Value {
func redact(v reflect.Value, tag string, global []string, depth int, seen map[any]int) reflect.Value {
switch v.Kind() {
case reflect.Pointer:
if v.IsNil() {
Expand All @@ -69,19 +74,19 @@ func redact(v reflect.Value, tag string, depth int, seen map[any]int) reflect.Va
seen[ident] = depth
defer delete(seen, ident)
}
return redact(v.Elem(), tag, depth+1, seen).Addr()
return redact(v.Elem(), tag, global, depth+1, seen).Addr()
case reflect.Interface:
if v.IsNil() {
return v
}
return redact(v.Elem(), tag, depth+1, seen)
return redact(v.Elem(), tag, global, depth+1, seen)
case reflect.Array:
if v.Len() == 0 {
return v
}
r := reflect.New(v.Type()).Elem()
for i := 0; i < v.Len(); i++ {
r.Index(i).Set(redact(v.Index(i), tag, depth+1, seen))
r.Index(i).Set(redact(v.Index(i), tag, global, depth+1, seen))
}
return r
case reflect.Slice:
Expand All @@ -104,7 +109,7 @@ func redact(v reflect.Value, tag string, depth int, seen map[any]int) reflect.Va
}
r := reflect.MakeSlice(v.Type(), v.Len(), v.Cap())
for i := 0; i < v.Len(); i++ {
r.Index(i).Set(redact(v.Index(i), tag, depth+1, seen))
r.Index(i).Set(redact(v.Index(i), tag, global, depth+1, seen))
}
return r
case reflect.Map:
Expand All @@ -119,19 +124,18 @@ func redact(v reflect.Value, tag string, depth int, seen map[any]int) reflect.Va
seen[ident] = depth
defer delete(seen, ident)
}
var private []string
private, global := nextPath(global)
if privateKey.CanConvert(v.Type().Key()) {
p := v.MapIndex(privateKey.Convert(v.Type().Key()))
if p.IsValid() && p.CanInterface() {
switch p := p.Interface().(type) {
case string:
private = []string{p}
private = append(private, p)
case []string:
private = p
private = append(private, p...)
case []any:
private = make([]string, len(p))
for i, s := range p {
private[i] = fmt.Sprint(s)
for _, s := range p {
private = append(private, fmt.Sprint(s))
}
}
}
Expand All @@ -142,11 +146,11 @@ func redact(v reflect.Value, tag string, depth int, seen map[any]int) reflect.Va
if slices.Contains(private, it.Key().String()) {
continue
}
r.SetMapIndex(it.Key(), redact(it.Value(), tag, depth+1, seen))
r.SetMapIndex(it.Key(), redact(it.Value(), tag, global, depth+1, seen))
}
return r
case reflect.Struct:
var private []string
private, global := nextPath(global)
rt := v.Type()
names := make([]string, rt.NumField())
for i := range names {
Expand Down Expand Up @@ -217,14 +221,33 @@ func redact(v reflect.Value, tag string, depth int, seen map[any]int) reflect.Va
continue
}
if r.Field(i).CanSet() {
r.Field(i).Set(redact(f, tag, depth+1, seen))
r.Field(i).Set(redact(f, tag, global, depth+1, seen))
}
}
return r
}
return v
}

func nextPath(global []string) (private, next []string) {
if len(global) == 0 {
return nil, nil
}
private = make([]string, 0, len(global))
for i, s := range global {
key, rest, more := strings.Cut(s, ".")
if more {
global[i] = rest
} else {
private = append(private, key)
}
}
slices.DeleteFunc(global, func(s string) bool {
return s == ""
})
return private, global
}

type cycle struct {
typ reflect.Type
}
Expand Down
57 changes: 56 additions & 1 deletion x-pack/filebeat/input/internal/private/private_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ package private
import (
"bytes"
"encoding/json"
"net/url"
"reflect"
"testing"

Expand All @@ -17,6 +18,7 @@ type redactTest struct {
name string
in any
tag string
global []string
want any
wantErr error
}
Expand Down Expand Up @@ -48,6 +50,59 @@ var redactTests = []redactTest{
"not_secret": "2",
}},
},
{
name: "map_string_inner_global",
in: map[string]any{
"inner": map[string]any{
"secret": "1",
"not_secret": "2",
}},
global: []string{"inner.secret"},
want: map[string]any{
"inner": map[string]any{
"not_secret": "2",
}},
},
{
name: "map_string_inner_next_inner_global",
in: map[string]any{
"inner": map[string]any{
"next_inner": map[string]any{
"secret": "1",
"not_secret": "2",
},
}},
global: []string{"inner.next_inner.secret"},
want: map[string]any{
"inner": map[string]any{
"next_inner": map[string]any{
"not_secret": "2",
},
}},
},
{
name: "map_string_inner_next_inner_params_global",
in: map[string]any{
"inner": map[string]any{
"next_inner": map[string]any{
"headers": url.Values{
"secret": []string{"1"},
"not_secret": []string{"2"},
},
"not_secret": "2",
},
}},
global: []string{"inner.next_inner.headers.secret"},
want: map[string]any{
"inner": map[string]any{
"next_inner": map[string]any{
"headers": url.Values{
"not_secret": []string{"2"},
},
"not_secret": "2",
},
}},
},
{
name: "map_slice",
in: map[string]any{
Expand Down Expand Up @@ -270,7 +325,7 @@ func TestRedact(t *testing.T) {
t.Fatalf("failed to get before state: %v", err)
}
}
got, err := Redact(test.in, test.tag)
got, err := Redact(test.in, test.tag, test.global)
if err != test.wantErr {

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t.Fatalf("unexpected error from Redact: %v", err)
}
Expand Down

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