CVE-2026-64256: xfs: don't wrap around quota ids in dqiterate

From: Greg Kroah-Hartman <[email protected]>

Description
===========

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

xfs: don't wrap around quota ids in dqiterate

LOLLM noticed that q_id is an unsigned 32-bit variable.  If it happens
to be set to XFS_DQ_ID_MAX due to a filesystem that actually has a dquot
for ID_MAX, then this addition will truncate to zero and the iteration
starts over.  Fix this by casting to u64.

The Linux kernel CVE team has assigned CVE-2026-64256 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.8 with commit 21d7500929c8a0b10e22a6755850c6f9a9280284 and fixed in 6.12.96 with commit 249e311c2ba392ceaf9ebfc145a46922946f069a
	Issue introduced in 6.8 with commit 21d7500929c8a0b10e22a6755850c6f9a9280284 and fixed in 6.18.39 with commit d1c4c40599c376aeb0c93068a2ae344e79ee4b90
	Issue introduced in 6.8 with commit 21d7500929c8a0b10e22a6755850c6f9a9280284 and fixed in 7.1.4 with commit 2b14fe1e0924c6b901f4256456342569c5397abe
	Issue introduced in 6.8 with commit 21d7500929c8a0b10e22a6755850c6f9a9280284 and fixed in 7.2-rc4 with commit d766e4e5e85d829629c3ba503802fe1303d7b591

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-64256
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	fs/xfs/scrub/dqiterate.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/249e311c2ba392ceaf9ebfc145a46922946f069a
	https://git.kernel.org/stable/c/d1c4c40599c376aeb0c93068a2ae344e79ee4b90
	https://git.kernel.org/stable/c/2b14fe1e0924c6b901f4256456342569c5397abe
	https://git.kernel.org/stable/c/d766e4e5e85d829629c3ba503802fe1303d7b591