Bug 1556757
| Summary: | Subpath volume mount does not receive setgid by fsGroup | |||
|---|---|---|---|---|
| Product: | OpenShift Container Platform | Reporter: | Jianwei Hou <jhou> | |
| Component: | Storage | Assignee: | Jan Safranek <jsafrane> | |
| Status: | CLOSED ERRATA | QA Contact: | Jianwei Hou <jhou> | |
| Severity: | medium | Docs Contact: | ||
| Priority: | medium | |||
| Version: | 3.9.0 | CC: | aos-bugs, aos-storage-staff, bchilds, hekumar | |
| Target Milestone: | --- | |||
| Target Release: | 3.9.z | |||
| Hardware: | Unspecified | |||
| OS: | Unspecified | |||
| Whiteboard: | ||||
| Fixed In Version: | Doc Type: | If docs needed, set a value | ||
| Doc Text: | Story Points: | --- | ||
| Clone Of: | ||||
| : | 1582610 (view as bug list) | Environment: | ||
| Last Closed: | 2018-05-17 06:42:42 UTC | Type: | Bug | |
| Regression: | --- | Mount Type: | --- | |
| Documentation: | --- | CRM: | ||
| Verified Versions: | Category: | --- | ||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | ||
| Cloudforms Team: | --- | Target Upstream Version: | ||
| Embargoed: | ||||
| Bug Depends On: | ||||
| Bug Blocks: | 1582610 | |||
This might be because recursive chmod of volume happens before subpath mount is created. The last security fixes seem to be cause of this. The reason is Fchmod in doSafeMakeDir(): https://github.com/openshift/origin/blob/77f8b2956b44a2ccb81f2805ae7f57247c03d8d2/vendor/k8s.io/kubernetes/pkg/util/mount/mount_linux.go#L998 if err = syscall.Fchmod(parentFD, uint32(perm)&uint32(os.ModePerm)); err != nil { return fmt.Errorf("chmod %q failed: %s", currentPath, err) } There are two issues: - "perm&os.ModePerm" filters out sticky and SUID/SGID bits, which is wrong - os.FileMode is not what fchmod() syscall expects - SUID/SGID/sticky flags are on different bits in os.FileMode and fchmod() argument. Opened issue upstream: https://github.com/kubernetes/kubernetes/issues/61283 Verfied on v3.9.20, this is fixed. Verified on 3.9.24 Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2018:1566 |
Description of problem: The mount path of subpath does not get the setgid bit by fsGroup. Version-Release number of selected component (if applicable): openshift v3.9.9 kubernetes v1.9.1+a0ce1bc657 etcd 3.2.16 How reproducible: Very Steps to Reproduce: 1. Create a Pod with emptyDir volume kind: Pod apiVersion: v1 metadata: { name: "subpath" } spec: volumes: - { name: "direct", emptyDir: {}} - { name: "subpath", emptyDir: {}} securityContext: fsGroup: 100 # games(35) is member in group users(100) runAsUser: 35 containers: - image: aosqe/hello-openshift name: show volumeMounts: - name: "direct" mountPath: "/mnt/direct" - name: "subpath" mountPath: "/mnt/subpath" subPath: "a" 2. oc rsh kind: Pod apiVersion: v1 metadata: { name: "subpath" } spec: volumes: - { name: "direct", emptyDir: {}} - { name: "subpath", emptyDir: {}} securityContext: fsGroup: 100 # games(35) is member in group users(100) runAsUser: 35 containers: - image: aosqe/hello-openshift name: show volumeMounts: - name: "direct" mountPath: "/mnt/direct" - name: "subpath" mountPath: "/mnt/subpath" subPath: "a" 2. oc exec subpath -- ls /mnt -l Actual results: # oc exec subpath -- ls /mnt -l total 0 drwxrwsrwx 2 root users 6 Mar 15 08:09 direct drwxrwxrwx 2 root users 6 Mar 15 08:09 subpath Noticed the setgid bit is x instead of s. Expected results: The subpath mount path should have setgid bit.