Merge pull request #1603 from lifupan/fix_fsgroup

Fix fsgroup

src/agent/src/mount.rs

@@ -17,6 +17,7 @@ use tokio::sync::Mutex;
 
 use libc::{c_void, mount};
 use nix::mount::{self, MsFlags};
+use nix::unistd::Gid;
 
 use regex::Regex;
 use std::fs::File;
@@ -45,6 +46,9 @@ pub const TYPE_ROOTFS: &str = "rootfs";
 
 pub const MOUNT_GUEST_TAG: &str = "kataShared";
 
+// Allocating an FSGroup that owns the pod's volumes
+const FS_GID: &str = "fsgid";
+
 #[rustfmt::skip]
 lazy_static! {
     pub static ref FLAGS: HashMap<&'static str, (bool, MsFlags)> = {
@@ -266,11 +270,24 @@ async fn local_storage_handler(
     let opts_vec: Vec<String> = storage.options.to_vec();
 
     let opts = parse_options(opts_vec);
-    let mode = opts.get("mode");
-    if let Some(mode) = mode {
+
+    let mut need_set_fsgid = false;
+    if let Some(fsgid) = opts.get(FS_GID) {
+        let gid = fsgid.parse::<u32>()?;
+
+        nix::unistd::chown(storage.mount_point.as_str(), None, Some(Gid::from_raw(gid)))?;
+        need_set_fsgid = true;
+    }
+
+    if let Some(mode) = opts.get("mode") {
         let mut permission = fs::metadata(&storage.mount_point)?.permissions();
 
-        let o_mode = u32::from_str_radix(mode, 8)?;
+        let mut o_mode = u32::from_str_radix(mode, 8)?;
+
+        if need_set_fsgid {
+            // set SetGid mode mask.
+            o_mode |= 0o2000;
+        }
         permission.set_mode(o_mode);
 
         fs::set_permissions(&storage.mount_point, permission)?;

src/runtime/virtcontainers/kata_agent.go

@@ -51,6 +51,9 @@ const (
 	// containers.
 	KataLocalDevType = "local"
 
+	// Allocating an FSGroup that owns the pod's volumes
+	fsGid = "fsgid"
+
 	// path to vfio devices
 	vfioPath = "/dev/vfio/"
 
@@ -1320,7 +1323,11 @@ func (k *kataAgent) createContainer(ctx context.Context, sandbox *Sandbox, c *Co
 	epheStorages := k.handleEphemeralStorage(ociSpec.Mounts)
 	ctrStorages = append(ctrStorages, epheStorages...)
 
-	localStorages := k.handleLocalStorage(ociSpec.Mounts, sandbox.id, c.rootfsSuffix)
+	localStorages, err := k.handleLocalStorage(ociSpec.Mounts, sandbox.id, c.rootfsSuffix)
+	if err != nil {
+		return nil, err
+	}
+
 	ctrStorages = append(ctrStorages, localStorages...)
 
 	// We replace all OCI mount sources that match our container mount
@@ -1419,10 +1426,27 @@ func (k *kataAgent) handleEphemeralStorage(mounts []specs.Mount) []*grpc.Storage
 
 // handleLocalStorage handles local storage within the VM
 // by creating a directory in the VM from the source of the mount point.
-func (k *kataAgent) handleLocalStorage(mounts []specs.Mount, sandboxID string, rootfsSuffix string) []*grpc.Storage {
+func (k *kataAgent) handleLocalStorage(mounts []specs.Mount, sandboxID string, rootfsSuffix string) ([]*grpc.Storage, error) {
 	var localStorages []*grpc.Storage
 	for idx, mnt := range mounts {
 		if mnt.Type == KataLocalDevType {
+			origin_src := mounts[idx].Source
+			stat := syscall.Stat_t{}
+			err := syscall.Stat(origin_src, &stat)
+			if err != nil {
+				k.Logger().WithError(err).Errorf("failed to stat %s", origin_src)
+				return nil, err
+			}
+
+			dir_options := localDirOptions
+
+			// if volume's gid isn't root group(default group), this means there's
+			// an specific fsGroup is set on this local volume, then it should pass
+			// to guest.
+			if stat.Gid != 0 {
+				dir_options = append(dir_options, fmt.Sprintf("%s=%d", fsGid, stat.Gid))
+			}
+
 			// Set the mount source path to a the desired directory point in the VM.
 			// In this case it is located in the sandbox directory.
 			// We rely on the fact that the first container in the VM has the same ID as the sandbox ID.
@@ -1437,12 +1461,12 @@ func (k *kataAgent) handleLocalStorage(mounts []specs.Mount, sandboxID string, r
 				Source:     KataLocalDevType,
 				Fstype:     KataLocalDevType,
 				MountPoint: mounts[idx].Source,
-				Options:    localDirOptions,
+				Options:    dir_options,
 			}
 			localStorages = append(localStorages, localStorage)
 		}
 	}
-	return localStorages
+	return localStorages, nil
 }
 
 // handleDeviceBlockVolume handles volume that is block device file

src/runtime/virtcontainers/kata_agent_test.go

@@ -205,7 +205,8 @@ func TestHandleEphemeralStorage(t *testing.T) {
 func TestHandleLocalStorage(t *testing.T) {
 	k := kataAgent{}
 	var ociMounts []specs.Mount
-	mountSource := "mountPoint"
+	mountSource := "/tmp/mountPoint"
+	os.Mkdir(mountSource, 0755)
 
 	mount := specs.Mount{
 		Type:   KataLocalDevType,
@@ -216,7 +217,7 @@ func TestHandleLocalStorage(t *testing.T) {
 	rootfsSuffix := "rootfs"
 
 	ociMounts = append(ociMounts, mount)
-	localStorages := k.handleLocalStorage(ociMounts, sandboxID, rootfsSuffix)
+	localStorages, _ := k.handleLocalStorage(ociMounts, sandboxID, rootfsSuffix)
 
 	assert.NotNil(t, localStorages)
 	assert.Equal(t, len(localStorages), 1)