mount: Add "no-default-permissions" option

This option restores the previous behavior of `mount` by disabling the "DefaultPermissions" FUSE option. This allows any user that can access the mountpoint to read any file from the snapshot. Normal FUSE rules apply, so `allow-root` or `allow-other` can be used to allow users besides the mounting user to access these files.

cmd/restic/cmd_mount.go

@@ -53,13 +53,14 @@ For details please see the documentation for time.Format() at:
 
 // MountOptions collects all options for the mount command.
 type MountOptions struct {
-	OwnerRoot        bool
-	AllowRoot        bool
-	AllowOther       bool
-	Host             string
-	Tags             restic.TagLists
-	Paths            []string
-	SnapshotTemplate string
+	OwnerRoot            bool
+	AllowRoot            bool
+	AllowOther           bool
+	NoDefaultPermissions bool
+	Host                 string
+	Tags                 restic.TagLists
+	Paths                []string
+	SnapshotTemplate     string
 }
 
 var mountOptions MountOptions
@@ -71,6 +72,7 @@ func init() {
 	mountFlags.BoolVar(&mountOptions.OwnerRoot, "owner-root", false, "use 'root' as the owner of files and dirs")
 	mountFlags.BoolVar(&mountOptions.AllowRoot, "allow-root", false, "allow root user to access the data in the mounted directory")
 	mountFlags.BoolVar(&mountOptions.AllowOther, "allow-other", false, "allow other users to access the data in the mounted directory")
+	mountFlags.BoolVar(&mountOptions.NoDefaultPermissions, "no-default-permissions", false, "for 'allow-other', ignore Unix permissions and allow users to read all snapshot files")
 
 	mountFlags.StringVarP(&mountOptions.Host, "host", "H", "", `only consider snapshots for this host`)
 	mountFlags.Var(&mountOptions.Tags, "tag", "only consider snapshots which include this `taglist`")
@@ -120,7 +122,9 @@ func mount(opts MountOptions, gopts GlobalOptions, mountpoint string) error {
 		mountOptions = append(mountOptions, systemFuse.AllowOther())
 	}
 
-	mountOptions = append(mountOptions, systemFuse.DefaultPermissions())
+	if !opts.NoDefaultPermissions {
+		mountOptions = append(mountOptions, systemFuse.DefaultPermissions())
+	}
 
 	c, err := systemFuse.Mount(mountpoint, mountOptions...)
 	if err != nil {