Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: ipc/shm: serialize orphan cleanup with shm_nattch updates shm_destroy_orphaned() walks the shm idr under shm_ids(ns).rwsem, but that does not serialize all fields tested by shm_may_destroy(). In particular, shm_nattch is updated while holding shm_perm.lock, and attach paths can do that without holding the rwsem. Do not decide that an orphaned segment is unused before taking the object lock. Move the shm_may_destroy() check under shm_perm.lock, matching the other destroy paths, and unlock the segment when it no longer qualifies for removal.

Affected versions

Linux: 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d through before b1e9aef48e4d8a0c1b54fb913077b0824ed7d650 (git); 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d through before 92cda2593cf2ed25b0e9d78e5e6d8303bba1a064 (git); 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d through before 1f0d01e35dbb228084d5187212e32c91a30dcbeb (git); 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d through before 6560be3f6a5bb84f006f184f0c966747bb58e1a3 (git); 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d through before b5107b4ce3ad45fcf369ee2058c8910620f4b5a8 (git); 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d through before db752ebfdaf2c7f27cd9690ef48b616af068319c (git); 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d through before 030bbc857bd51d4b25a90d931d3f8775ef22823a (git); 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d through before 2e5c6f4fd4001562781e99bbfc7f1f0127187542 (git); 3.1; V3.1.6 through before * (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.