Merge pull request 2017 from kylewlacy/fuse_default_permissions_option

mount: Add default-permissions flag to set FUSE option

changelog/unreleased/pull-2017

@@ -0,0 +1,11 @@
+Enhancement: mount: Enforce FUSE Unix permissions with allow-other
+
+The fuse mount (`restic mount`) now lets the kernel check the permissions of
+the files within snapshots (this is done through the `DefaultPermissions` FUSE
+option) when the option `--allow-other` is specified.
+
+To restore the old behavior, we've added the `--no-default-permissions` option.
+This allows all users that have access to the mount point to access all
+files within the snapshots.
+
+https://github.com/restic/restic/pull/2017

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`")
@@ -118,6 +120,11 @@ func mount(opts MountOptions, gopts GlobalOptions, mountpoint string) error {
 
 	if opts.AllowOther {
 		mountOptions = append(mountOptions, systemFuse.AllowOther())
+
+		// let the kernel check permissions unless it is explicitly disabled
+		if !opts.NoDefaultPermissions {
+			mountOptions = append(mountOptions, systemFuse.DefaultPermissions())
+		}
 	}
 
 	c, err := systemFuse.Mount(mountpoint, mountOptions...)