feat: Add read-only flag to FTP server

cmd/stfs/cmd/serve_ftp.go

@@ -37,6 +37,7 @@ const (
 	signatureRecipientFlag = "signature-recipient"
 
 	cacheWriteFlag = "cache-write-type"
+	readOnlyFlag   = "read-only"
 )
 
 var (
@@ -197,6 +198,7 @@ var serveFTPCmd = &cobra.Command{
 				)
 			},
 			true, // FTP needs read permission for `STOR` command even if O_WRONLY is set
+			viper.GetBool(readOnlyFlag),
 
 			func(hdr *config.Header) {
 				jsonLogger.Trace("Header transform", hdr)
@@ -313,6 +315,7 @@ func init() {
 	serveFTPCmd.PersistentFlags().StringP(cacheWriteFlag, "q", config.WriteCacheTypeFile, fmt.Sprintf("Write cache to use (default %v, available are %v)", config.WriteCacheTypeFile, config.KnownWriteCacheTypes))
 	serveFTPCmd.PersistentFlags().DurationP(cacheDurationFlag, "u", time.Hour, "Duration until cache is invalidated")
 	serveFTPCmd.PersistentFlags().StringP(cacheDirFlag, "w", cacheDir, "Directory to use if dir cache is enabled")
+	serveFTPCmd.PersistentFlags().BoolP(readOnlyFlag, "j", false, "Block all write operations")
 
 	viper.AutomaticEnv()
 

cmd/stfs/cmd/serve_http.go

@@ -131,6 +131,7 @@ var serveHTTPCmd = &cobra.Command{
 			"",    // We never write
 			nil,   // We never write
 			false, // We never write
+			true,  // We never write
 
 			func(hdr *config.Header) {
 				jsonLogger.Trace("Header transform", hdr)

examples/fs/main.go

@@ -144,6 +144,7 @@ func main() {
 			)
 		},
 		false,
+		false,
 
 		func(hdr *config.Header) {
 			l.Trace("Header transform", hdr)

pkg/fs/filesystem.go

@@ -30,6 +30,7 @@ type STFS struct {
 
 	compressionLevel           string
 	getFileBuffer              func() (cache.WriteCache, func() error, error)
+	readOnly                   bool
 	ignoreReadWritePermissions bool
 
 	ioLock sync.Mutex
@@ -47,6 +48,7 @@ func NewSTFS(
 	compressionLevel string,
 	getFileBuffer func() (cache.WriteCache, func() error, error),
 	ignorePermissionFlags bool,
+	readOnly bool,
 
 	onHeader func(hdr *config.Header),
 	log logging.StructuredLogger,
@@ -60,6 +62,7 @@ func NewSTFS(
 		compressionLevel:           compressionLevel,
 		getFileBuffer:              getFileBuffer,
 		ignoreReadWritePermissions: ignorePermissionFlags,
+		readOnly:                   readOnly,
 
 		onHeader: onHeader,
 		log:      log,
@@ -82,6 +85,10 @@ func (f *STFS) Create(name string) (afero.File, error) {
 		"name": name,
 	})
 
+	if f.readOnly {
+		return nil, os.ErrPermission
+	}
+
 	return f.OpenFile(name, os.O_CREATE|os.O_RDWR, 0666)
 }
 
@@ -91,6 +98,10 @@ func (f *STFS) mknodeWithoutLocking(dir bool, name string, perm os.FileMode, ove
 		"perm": perm,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	usr, err := user.Current()
 	if err != nil {
 		return err
@@ -171,6 +182,10 @@ func (f *STFS) MkdirRoot(name string, perm os.FileMode) error {
 		"perm": perm,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()
 
@@ -192,6 +207,10 @@ func (f *STFS) Mkdir(name string, perm os.FileMode) error {
 		"perm": perm,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()
 
@@ -204,6 +223,10 @@ func (f *STFS) MkdirAll(path string, perm os.FileMode) error {
 		"perm": perm,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()
 
@@ -244,30 +267,36 @@ func (f *STFS) OpenFile(name string, flag int, perm os.FileMode) (afero.File, er
 	defer f.ioLock.Unlock()
 
 	flags := &ifs.FileFlags{}
-	if flag&os.O_RDONLY != 0 {
+	if f.readOnly {
-		flags.Read = true
+		if flag&os.O_RDONLY != 0 || flag&os.O_RDWR != 0 || f.ignoreReadWritePermissions {
-	}
+			flags.Read = true
+		}
+	} else {
+		if flag&os.O_RDONLY != 0 {
+			flags.Read = true
+		}
 
-	if flag&os.O_WRONLY != 0 {
+		if flag&os.O_WRONLY != 0 {
-		flags.Write = true
+			flags.Write = true
-	}
+		}
 
-	if flag&os.O_RDWR != 0 {
+		if flag&os.O_RDWR != 0 {
-		flags.Read = true
+			flags.Read = true
-		flags.Write = true
+			flags.Write = true
-	}
+		}
 
-	if f.ignoreReadWritePermissions {
+		if f.ignoreReadWritePermissions {
-		flags.Read = true
+			flags.Read = true
-		flags.Write = true
+			flags.Write = true
-	}
+		}
 
-	if flag&os.O_APPEND != 0 {
+		if flag&os.O_APPEND != 0 {
-		flags.Append = true
+			flags.Append = true
-	}
+		}
 
-	if flag&os.O_TRUNC != 0 {
+		if flag&os.O_TRUNC != 0 {
-		flags.Truncate = true
+			flags.Truncate = true
+		}
 	}
 
 	hdr, err := inventory.Stat(
@@ -280,7 +309,7 @@ func (f *STFS) OpenFile(name string, flag int, perm os.FileMode) (afero.File, er
 	)
 	if err != nil {
 		if err == sql.ErrNoRows {
-			if flag&os.O_CREATE != 0 && flag&os.O_EXCL == 0 {
+			if !f.readOnly && flag&os.O_CREATE != 0 && flag&os.O_EXCL == 0 {
 				if err := f.mknodeWithoutLocking(false, name, perm, false, ""); err != nil {
 					return nil, err
 				}
@@ -299,7 +328,6 @@ func (f *STFS) OpenFile(name string, flag int, perm os.FileMode) (afero.File, er
 			} else {
 				return nil, os.ErrNotExist
 			}
-
 		} else {
 			return nil, err
 		}
@@ -332,6 +360,10 @@ func (f *STFS) Remove(name string) error {
 		"name": name,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()
 
@@ -343,6 +375,10 @@ func (f *STFS) RemoveAll(path string) error {
 		"path": path,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()
 
@@ -355,6 +391,10 @@ func (f *STFS) Rename(oldname, newname string) error {
 		"newname": newname,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()
 
@@ -389,6 +429,10 @@ func (f *STFS) Stat(name string) (os.FileInfo, error) {
 }
 
 func (f *STFS) updateMetadata(hdr *tar.Header) error {
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	done := false
 	if _, err := f.writeOps.Update(
 		func() (config.FileConfig, error) {
@@ -420,6 +464,10 @@ func (f *STFS) Chmod(name string, mode os.FileMode) error {
 		"name": mode,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()
 
@@ -451,6 +499,10 @@ func (f *STFS) Chown(name string, uid, gid int) error {
 		"gid":  gid,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()
 
@@ -483,6 +535,10 @@ func (f *STFS) Chtimes(name string, atime time.Time, mtime time.Time) error {
 		"mtime": mtime,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()
 
@@ -549,6 +605,10 @@ func (f *STFS) SymlinkIfPossible(oldname, newname string) error {
 		"newname": newname,
 	})
 
+	if f.readOnly {
+		return os.ErrPermission
+	}
+
 	f.ioLock.Lock()
 	defer f.ioLock.Unlock()