- Fixed cleanup of Pod volume mounts when a file was used as a subpath. ([#123052](https://github.com/kubernetes/kubernetes/pull/123052), [@jsafrane](https://github.com/jsafrane)) [SIG Node]

### CVE-2021-25741: Symlink Exchange Can Allow Host Filesystem Access

A security issue was discovered in Kubernetes where a user may be able to
create a container with subpath volume mounts to access files &
directories outside of the volume, including on the host filesystem.

**Affected Versions**:
  - kubelet v1.22.0 - v1.22.1
  - kubelet v1.21.0 - v1.21.4
  - kubelet v1.20.0 - v1.20.10

### Bug or Regression

- Fixed cleanup of Pod volume mounts when a file was used as a subpath. ([#123052](https://github.com/kubernetes/kubernetes/pull/123052), [@jsafrane](https://github.com/jsafrane)) [SIG Node]

        @Test
        @DisplayName("Binary constructor happy path and round-trip via toByteArray")
        void testBinaryConstructorAndToByteArray() {
            // Arrange: revision=1, count=2, identAuth zeros except last byte, subauth 10, 20
            byte[] ident = new byte[] { 0, 0, 0, 0, 0, 5 };
            rpc.sid_t st = buildSidT((byte) 1, ident, 10, 20);

            byte[] bytes = SID.toByteArray(st);

- Fixed cleanup of Pod volume mounts when a file was used as a subpath. ([#123052](https://github.com/kubernetes/kubernetes/pull/123052), [@jsafrane](https://github.com/jsafrane)) [SIG Node]

- Make sure auto-mounted subpath mount source is already mounted ([#112498](https://github.com/kubernetes/kubernetes/pull/112498), [@andyzhangx](https://github.com/andyzhangx)) [SIG Storage]

## Dependencies

### Added
_Nothing has changed._

ah????ok!.&a&dusay?kadih?mayotom?r&ah&im?usuy??umakan??sot!ihsin??wa&g&atik?odoyin??k&as?o????i&esieg?hco!k??jamu?k&a!sus??usto??ma&gak?k??rahan??o&mukus?n&i?ust!ihsagih???torum?yot!o???u&koknan?zimihsasot????ugamay!.&a&m&ayukot?ihso??toyot??e&bu?subat??i&gah?kesonomihs?nukawi?rakih??nanuhs?otagan?u&ba?foh?otim?stamaduk?uy?????s&anamay!.&a&dihsoyijuf?mayabat?r&ahoneu?ustakihsin??w&a&k&ayah?ijuf??suran??ohs???egusok?i&ak?h&cimakan?s&anamay?od???k&asarin?u&feuf?sto????o&k&akanamay?ihcugawakijuf??n...