CVE-2026-53043

In the Linux kernel, the following vulnerability has been resolved:

ocfs2/dlm: validate qrnumregions in dlmmatch_regions()

Patch series "ocfs2/dlm: fix two bugs in dlmmatchregions()".

In dlmmatchregions(), the qrnumregions field from a DLMQUERY_REGION

network message is used to drive loops over the qr_regions buffer without

sufficient validation.  This series fixes two issues:

• Patch 1 adds a bounds check to reject messages where qr_numregions

  exceeds O2NMMAXREGIONS. The o2net layer only validates message

  byte length; it does not constrain field values, so a crafted message

  can set qr_numregions up to 255 and trigger out-of-bounds reads past

  the 1024-byte qr_regions buffer.

• Patch 2 fixes an off-by-one in the local-vs-remote comparison loop,

  which uses '<=' instead of '<', reading one entry past the valid range

  even when qr_numregions is within bounds.

​

This patch (of 2):

The qrnumregions field from a DLMQUERY_REGION network message is used

directly as loop bounds in dlmmatchregions() without checking against

O2NMMAXREGIONS.  Since qrregions is sized for at most O2NMMAX_REGIONS

(32) entries, a crafted message with qr_numregions > 32 causes

out-of-bounds reads past the qr_regions buffer.

Add a bounds check for qr_numregions before entering the loops.