linux-cve-announce - CVE-2022-49828: hugetlbfs: don't delete error page from pagecache

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Message-ID: <2025050136-CVE-2022-49828-7143@gregkh>
Date: Thu,  1 May 2025 16:10:18 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-49828: hugetlbfs: don't delete error page from pagecache

From: Greg Kroah-Hartman <gregkh@...nel.org>

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

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

hugetlbfs: don't delete error page from pagecache

This change is very similar to the change that was made for shmem [1], and
it solves the same problem but for HugeTLBFS instead.

Currently, when poison is found in a HugeTLB page, the page is removed
from the page cache.  That means that attempting to map or read that
hugepage in the future will result in a new hugepage being allocated
instead of notifying the user that the page was poisoned.  As [1] states,
this is effectively memory corruption.

The fix is to leave the page in the page cache.  If the user attempts to
use a poisoned HugeTLB page with a syscall, the syscall will fail with
EIO, the same error code that shmem uses.  For attempts to map the page,
the thread will get a BUS_MCEERR_AR SIGBUS.

[1]: commit a76054266661 ("mm: shmem: don't truncate page if memory failure happens")

The Linux kernel CVE team has assigned CVE-2022-49828 to this issue.

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

	Fixed in 5.15.80 with commit 30571f28bb35c826219971c63bcf60d2517112ed
	Fixed in 6.0.10 with commit ec667443b2dbc6cdbbac4073e51a17733158ec6a
	Fixed in 6.1 with commit 8625147cafaa9ba74713d682f5185eb62cb2aedb

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-2022-49828
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/hugetlbfs/inode.c
	mm/hugetlb.c
	mm/memory-failure.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/30571f28bb35c826219971c63bcf60d2517112ed
	https://git.kernel.org/stable/c/ec667443b2dbc6cdbbac4073e51a17733158ec6a
	https://git.kernel.org/stable/c/8625147cafaa9ba74713d682f5185eb62cb2aedb