fix(secrets): Avoid count underflow by only counting initialized secrets (#14991)

config/config.go

@@ -478,7 +478,12 @@ func (c *Config) LoadAll(configFiles ...string) error {
 	}
 
 	// Check if there is enough lockable memory for the secret
-	c.NumberSecrets = uint64(secretCount.Load())
+	count := secretCount.Load()
+	if count < 0 {
+		log.Printf("E! Invalid secret count %d, please report this incident including your configuration!", count)
+		count = 0
+	}
+	c.NumberSecrets = uint64(count)
 
 	// Let's link all secrets to their secret-stores
 	return c.LinkSecrets()

config/config_test.go

@@ -1293,6 +1293,7 @@ type MockupInputPlugin struct {
 	MaxBodySize  config.Size     `toml:"max_body_size"`
 	Paths        []string        `toml:"paths"`
 	Port         int             `toml:"port"`
+	Password     config.Secret   `toml:"password"`
 	Command      string
 	Files        []string
 	PidFile      string

config/secret.go

@@ -155,11 +155,11 @@ func (s *Secret) Destroy() {
 	if s.container != nil {
 		s.container.Destroy()
 		s.container = nil
-	}
 
-	// Keep track of the number of secrets...
+		// Keep track of the number of used secrets...
 		secretCount.Add(-1)
 	}
+}
 
 // Empty return if the secret is completely empty
 func (s *Secret) Empty() bool {

config/secret_test.go

@@ -351,6 +351,31 @@ func TestSecretEnvironmentVariable(t *testing.T) {
 	require.EqualValues(t, "an env secret", secret.TemporaryString())
 }
 
+func TestSecretCount(t *testing.T) {
+	secretCount.Store(0)
+	cfg := []byte(`
+[[inputs.mockup]]
+
+[[inputs.mockup]]
+  secret = "a secret"
+
+[[inputs.mockup]]
+  secret = "another secret"
+`)
+
+	c := NewConfig()
+	require.NoError(t, c.LoadConfigData(cfg))
+	require.Len(t, c.Inputs, 3)
+	require.Equal(t, int64(2), secretCount.Load())
+
+	// Remove all secrets and check
+	for _, ri := range c.Inputs {
+		input := ri.Input.(*MockupSecretPlugin)
+		input.Secret.Destroy()
+	}
+	require.Equal(t, int64(0), secretCount.Load())
+}
+
 func TestSecretStoreStatic(t *testing.T) {
 	cfg := []byte(
 		`