Linux Kernel Netfs Partial Invalidation of Streaming-Write Folio Vulnerability

A vulnerability exists in the Linux kernel's netfs component, specifically in the handling of partial invalidations of streaming-write folios. When a partial invalidation overlaps with dirty write data cached in a streaming write page, the netfs_invalidate_folio() function incorrectly adjusts the dirty region by moving it forward, rather than properly aligning it with the end of the invalidation. This issue affects several versions of the Linux kernel.

Impact

The vulnerability can lead to incorrect management of dirty write caches in streaming write pages, potentially causing data consistency issues.

Reproduction

To reproduce this vulnerability, create a scenario where a streaming-write folio has a dirty region that is not fully up-to-date. Then, initiate a partial invalidation that overlaps with the front of the dirty region. The netfs_invalidate_folio() function will incorrectly adjust the dirty offset, highlighting the vulnerability.

Remediation

Users can apply the latest patches available in the Linux kernel stable tree to address this vulnerability.