Mask password discovered via module autodiscover hint (elastic#15616)

* Mask password is string representation of config

* Rename method

* Adding unit test

* Use const for module config password setting name

* Using common.DebugString

* Simplifying

* Removing now-invalid unit test

* Removing now-unnecessary const

* Refactoring: moving debug-related var and func to common file

* Refactoring: rename from black list to mask list

* Implement fmt.Formatter for common.MapStr

* Reintroduce debug statement

* Make MarshalLogObject always filter MapStr object for logging purposes

* Refactoring: renaming to be bit more generic

* Forgot to add license header to new file

* Fixing verb syntax

libbeat/common/config.go

@@ -66,18 +66,6 @@ const (
 	selectorConfigWithPassword = "config-with-passwords"
 )
 
-var debugBlacklist = MakeStringSet(
-	"password",
-	"passphrase",
-	"key_passphrase",
-	"pass",
-	"proxy_url",
-	"url",
-	"urls",
-	"host",
-	"hosts",
-)
-
 // make hasSelector and configDebugf available for unit testing
 var hasSelector = logp.HasSelector
 var configDebugf = logp.Debug
@@ -369,7 +357,7 @@ func DebugString(c *Config, filterPrivate bool) string {
 			return fmt.Sprintf("<config error> %v", err)
 		}
 		if filterPrivate {
-			filterDebugObject(content)
+			applyLoggingMask(content)
 		}
 		j, _ := json.MarshalIndent(content, "", "  ")
 		bufs = append(bufs, string(j))
@@ -380,7 +368,7 @@ func DebugString(c *Config, filterPrivate bool) string {
 			return fmt.Sprintf("<config error> %v", err)
 		}
 		if filterPrivate {
-			filterDebugObject(content)
+			applyLoggingMask(content)
 		}
 		j, _ := json.MarshalIndent(content, "", "  ")
 		bufs = append(bufs, string(j))
@@ -392,30 +380,6 @@ func DebugString(c *Config, filterPrivate bool) string {
 	return strings.Join(bufs, "\n")
 }
 
-func filterDebugObject(c interface{}) {
-	switch cfg := c.(type) {
-	case map[string]interface{}:
-		for k, v := range cfg {
-			if debugBlacklist.Has(k) {
-				if arr, ok := v.([]interface{}); ok {
-					for i := range arr {
-						arr[i] = "xxxxx"
-					}
-				} else {
-					cfg[k] = "xxxxx"
-				}
-			} else {
-				filterDebugObject(v)
-			}
-		}
-
-	case []interface{}:
-		for _, elem := range cfg {
-			filterDebugObject(elem)
-		}
-	}
-}
-
 // OwnerHasExclusiveWritePerms asserts that the current user or root is the
 // owner of the config file and that the config file is (at most) writable by
 // the owner or root (e.g. group and other cannot have write access).

libbeat/common/logging.go

@@ -0,0 +1,54 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package common
+
+var maskList = MakeStringSet(
+	"password",
+	"passphrase",
+	"key_passphrase",
+	"pass",
+	"proxy_url",
+	"url",
+	"urls",
+	"host",
+	"hosts",
+)
+
+func applyLoggingMask(c interface{}) {
+	switch cfg := c.(type) {
+	case map[string]interface{}:
+		for k, v := range cfg {
+			if maskList.Has(k) {
+				if arr, ok := v.([]interface{}); ok {
+					for i := range arr {
+						arr[i] = "xxxxx"
+					}
+				} else {
+					cfg[k] = "xxxxx"
+				}
+			} else {
+				applyLoggingMask(v)
+			}
+		}
+
+	case []interface{}:
+		for _, elem := range cfg {
+			applyLoggingMask(elem)
+		}
+	}
+}

libbeat/common/mapstr.go

@@ -20,6 +20,7 @@ package common
 import (
 	"encoding/json"
 	"fmt"
+	"io"
 	"sort"
 	"strings"
 
@@ -218,13 +219,16 @@ func (m MapStr) MarshalLogObject(enc zapcore.ObjectEncoder) error {
 		return nil
 	}
 
-	keys := make([]string, 0, len(m))
-	for k := range m {
+	debugM := m.Clone()
+	applyLoggingMask(map[string]interface{}(debugM))
+
+	keys := make([]string, 0, len(debugM))
+	for k := range debugM {
 		keys = append(keys, k)
 	}
 	sort.Strings(keys)
 	for _, k := range keys {
-		v := m[k]
+		v := debugM[k]
 		if inner, ok := tryToMapStr(v); ok {
 			enc.AddObject(k, inner)
 			continue
@@ -234,6 +238,19 @@ func (m MapStr) MarshalLogObject(enc zapcore.ObjectEncoder) error {
 	return nil
 }
 
+// Format implements fmt.Formatter
+func (m MapStr) Format(f fmt.State, c rune) {
+	if f.Flag('+') || f.Flag('#') {
+		io.WriteString(f, m.String())
+		return
+	}
+
+	debugM := m.Clone()
+	applyLoggingMask(map[string]interface{}(debugM))
+
+	io.WriteString(f, debugM.String())
+}
+
 // Flatten flattens the given MapStr and returns a flat MapStr.
 //
 // Example:

libbeat/common/mapstr_test.go

@@ -1002,3 +1002,26 @@ func BenchmarkWalkMap(b *testing.B) {
 		}
 	})
 }
+
+func TestFormat(t *testing.T) {
+	input := MapStr{
+		"foo":      "bar",
+		"password": "SUPER_SECURE",
+	}
+
+	tests := map[string]string{
+		"%v":  `{"foo":"bar","password":"xxxxx"}`,
+		"%+v": `{"foo":"bar","password":"SUPER_SECURE"}`,
+		"%#v": `{"foo":"bar","password":"SUPER_SECURE"}`,
+		"%s":  `{"foo":"bar","password":"xxxxx"}`,
+		"%+s": `{"foo":"bar","password":"SUPER_SECURE"}`,
+		"%#s": `{"foo":"bar","password":"SUPER_SECURE"}`,
+	}
+
+	for verb, expected := range tests {
+		t.Run(verb, func(t *testing.T) {
+			actual := fmt.Sprintf(verb, input)
+			assert.Equal(t, expected, actual)
+		})
+	}
+}

metricbeat/autodiscover/builder/hints/metrics.go

@@ -141,14 +141,14 @@ func (m *metricHints) CreateConfig(event bus.Event) []*common.Config {
 		moduleConfig["password"] = password
 	}
 
-	logp.Debug("hints.builder", "generated config: %v", moduleConfig.String())
+	logp.Debug("hints.builder", "generated config: %v", moduleConfig)
 
 	// Create config object
 	cfg, err := common.NewConfigFrom(moduleConfig)
 	if err != nil {
 		logp.Debug("hints.builder", "config merge failed with error: %v", err)
 	}
-	logp.Debug("hints.builder", "generated config: +%v", *cfg)
+	logp.Debug("hints.builder", "generated config: %+v", common.DebugString(cfg, true))
 	config = append(config, cfg)
 
 	// Apply information in event to the template to generate the final config