Fix G302 gosec issues (#10378)

Signed-off-by: Dimitar Dimitrov <dimitar.dimitrov@grafana.com>

.golangci.yml

@@ -69,6 +69,7 @@ linters-settings:
       - G109
       - G112
       - G114
+      - G302
 
 run:
   timeout: 10m

pkg/mimirtool/commands/config.go

@@ -107,7 +107,7 @@ func (c *ConfigCommand) output(yamlContents []byte, flags []string, notices conf
 		if path == "" {
 			return defaultWriter, func() {}, nil
 		}
-		outWriter, err := os.OpenFile(path, os.O_TRUNC|os.O_CREATE|os.O_WRONLY, 0666)
+		outWriter, err := os.OpenFile(path, os.O_TRUNC|os.O_CREATE|os.O_WRONLY, 0600)
 		if err != nil {
 			return nil, nil, errors.Wrap(err, "could not open "+path)
 		}

pkg/util/activitytracker/activity_tracker.go

@@ -172,7 +172,7 @@ func trimEntryToSize(entry string, size int) string {
 }
 
 func getMappedFile(filename string, filesize int) (*os.File, mmap.MMap, error) {
-	file, err := os.OpenFile(filename, os.O_CREATE|os.O_RDWR|os.O_TRUNC, 0666)
+	file, err := os.OpenFile(filename, os.O_CREATE|os.O_RDWR|os.O_TRUNC, 0600)
 	if err != nil {
 		return nil, nil, errors.Wrap(err, "failed to create activity file")
 	}

pkg/util/shutdownmarker/shutdown_marker.go

@@ -29,7 +29,7 @@ func Remove(p string) error {
 		return err
 	}
 
-	dir, err := os.OpenFile(path.Dir(p), os.O_RDONLY, 0777)
+	dir, err := os.OpenFile(path.Dir(p), os.O_RDONLY, 0600) // mode doesn't matter since we're not passing os.O_CREATE
 	if err != nil {
 		return err
 	}