[LU-12266] Fix up non-directory creation in SGID directories

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.13.0, Lustre 2.12.2, Lustre 2.10.8
• Affects Version/s: Lustre 2.10.7, Lustre 2.12.1
• Severity: 3
• Assignee: Sebastien Buisson
• Reporter: Sebastien Buisson

Description

If a non-directory item is created in a SGID directory, it is possible that the SGID flag is not properly cleared, leaving the item with incorrect group ownership and flags.

This is mitigated by mounting Lustre with the -o nosuid mount option on the client.

The upstream kernel has a similar issue that was fixed in commit https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0fa3ecd87848c9c93c2c828ef4c3a8ca36ce46c7