Make Mount.Type optional for bind mounts

According to the OCI spec Mount.Type is an optional field and it
defaults to "bind" when any of "bind" or "rbind" is included in
Mount.Options.

Also fix the shim to remove bind/rbind from options when mount is
converted from bind to tmpfs inside the Sentry.

Fixes #2330
Fixes #3274

PiperOrigin-RevId: 371996891

2 files changed, 22 insertions, 1 deletions

diff --git a/runsc/container/container_test.go b/runsc/container/container_test.go
index 5a0c468a4..0e79877b7 100644
--- a/runsc/container/container_test.go
+++ b/runsc/container/container_test.go
@@ -2449,6 +2449,27 @@ func TestCreateWithCorruptedStateFile(t *testing.T) {
 	}
 }
 
+func TestBindMountByOption(t *testing.T) {
+	for name, conf := range configs(t, all...) {
+		t.Run(name, func(t *testing.T) {
+			dir, err := ioutil.TempDir(testutil.TmpDir(), "bind-mount")
+			spec := testutil.NewSpecWithArgs("/bin/touch", path.Join(dir, "file"))
+			if err != nil {
+				t.Fatalf("ioutil.TempDir(): %v", err)
+			}
+			spec.Mounts = append(spec.Mounts, specs.Mount{
+				Destination: dir,
+				Source:      dir,
+				Type:        "none",
+				Options:     []string{"rw", "bind"},
+			})
+			if err := run(spec, conf); err != nil {
+				t.Fatalf("error running sandbox: %v", err)
+			}
+		})
+	}
+}
+
 func execute(cont *Container, name string, arg ...string) (unix.WaitStatus, error) {
 	args := &control.ExecArgs{
 		Filename: name,
diff --git a/runsc/container/multi_container_test.go b/runsc/container/multi_container_test.go
index 0f0a223ce..37ad7d2e1 100644
--- a/runsc/container/multi_container_test.go
+++ b/runsc/container/multi_container_test.go
@@ -1510,7 +1510,7 @@ func TestMultiContainerSharedMountUnsupportedOptions(t *testing.T) {
 				Destination: "/mydir/test",
 				Source:      "/some/dir",
 				Type:        "tmpfs",
-				Options:     []string{"rw", "rbind", "relatime"},
+				Options:     []string{"rw", "relatime"},
 			}
 			podSpec[0].Mounts = append(podSpec[0].Mounts, mnt0)