main: add "-o" option to enable "suid" and "dev"

Device files and suid binaries are often not needed when running
gocryptfs as root. As they are potentially dangerous, let the
user enable them explicitely via the new "-o" option instead of
always enabling them when running as root.

1 files changed, 9 insertions, 9 deletions

diff --git a/main.go b/main.go
index 68dfb0a..b5de959 100644
--- a/main.go
+++ b/main.go
@@ -45,7 +45,7 @@ type argContainer struct {
 	plaintextnames, quiet, nosyslog, wpanic,
 	longnames, allow_other, ro bool
 	masterkey, mountpoint, cipherdir, cpuprofile, config, extpass,
-	memprofile string
+	memprofile, o string
 	notifypid, scryptn int
 }
 
@@ -185,6 +185,7 @@ func main() {
 	flagSet.StringVar(&args.memprofile, "memprofile", "", "Write memory profile to specified file")
 	flagSet.StringVar(&args.config, "config", "", "Use specified config file instead of CIPHERDIR/gocryptfs.conf")
 	flagSet.StringVar(&args.extpass, "extpass", "", "Use external program for the password prompt")
+	flagSet.StringVar(&args.o, "o", "", "Pass additional mount options to the kernel, comma-separated list")
 	flagSet.IntVar(&args.notifypid, "notifypid", 0, "Send USR1 to the specified process after "+
 		"successful mount - used internally for daemonization")
 	flagSet.IntVar(&args.scryptn, "scryptn", configfile.ScryptDefaultLogN, "scrypt cost parameter logN. "+
@@ -402,13 +403,6 @@ func initFuseFrontend(key []byte, args argContainer, confFile *configfile.ConfFi
 		// Make the kernel check the file permissions for us
 		mOpts.Options = append(mOpts.Options, "default_permissions")
 	}
-	if os.Getuid() == 0 {
-		// FUSE filesystems are mounted with "nodev" by default. If we run as root,
-		// we can use device files by passing the opposite mount option, "dev".
-		mOpts.Options = append(mOpts.Options, "dev")
-		// Same thing for "nosuid". If we run as root, we can pass "suid".
-		mOpts.Options = append(mOpts.Options, "suid")
-	}
 	// Set values shown in "df -T" and friends
 	// First column, "Filesystem"
 	mOpts.Options = append(mOpts.Options, "fsname="+args.cipherdir)
@@ -419,7 +413,13 @@ func initFuseFrontend(key []byte, args argContainer, confFile *configfile.ConfFi
 	if args.ro {
 		mOpts.Options = append(mOpts.Options, "ro")
 	}
-
+	// Add additional mount options (if any) after the stock ones, so the user has
+	// a chance to override them.
+	if args.o != "" {
+		parts := strings.Split(args.o, ",")
+		tlog.Debug.Printf("Adding -o mount options: %v", parts)
+		mOpts.Options = append(mOpts.Options, parts...)
+	}
 	srv, err := fuse.NewServer(conn.RawFS(), args.mountpoint, &mOpts)
 	if err != nil {
 		tlog.Fatal.Printf("Mount failed: %v", err)