linux-cve-announce - CVE-2025-21933: arm: pgtable: fix NULL pointer dereference issue

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2025040134-CVE-2025-21933-2f5b@gregkh>
Date: Tue,  1 Apr 2025 16:39:57 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2025-21933: arm: pgtable: fix NULL pointer dereference issue

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

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

arm: pgtable: fix NULL pointer dereference issue

When update_mmu_cache_range() is called by update_mmu_cache(), the vmf
parameter is NULL, which will cause a NULL pointer dereference issue in
adjust_pte():

Unable to handle kernel NULL pointer dereference at virtual address 00000030 when read
Hardware name: Atmel AT91SAM9
PC is at update_mmu_cache_range+0x1e0/0x278
LR is at pte_offset_map_rw_nolock+0x18/0x2c
Call trace:
 update_mmu_cache_range from remove_migration_pte+0x29c/0x2ec
 remove_migration_pte from rmap_walk_file+0xcc/0x130
 rmap_walk_file from remove_migration_ptes+0x90/0xa4
 remove_migration_ptes from migrate_pages_batch+0x6d4/0x858
 migrate_pages_batch from migrate_pages+0x188/0x488
 migrate_pages from compact_zone+0x56c/0x954
 compact_zone from compact_node+0x90/0xf0
 compact_node from kcompactd+0x1d4/0x204
 kcompactd from kthread+0x120/0x12c
 kthread from ret_from_fork+0x14/0x38
Exception stack(0xc0d8bfb0 to 0xc0d8bff8)

To fix it, do not rely on whether 'ptl' is equal to decide whether to hold
the pte lock, but decide it by whether CONFIG_SPLIT_PTE_PTLOCKS is
enabled.  In addition, if two vmas map to the same PTE page, there is no
need to hold the pte lock again, otherwise a deadlock will occur.  Just
add the need_lock parameter to let adjust_pte() know this information.

The Linux kernel CVE team has assigned CVE-2025-21933 to this issue.


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

	Issue introduced in 6.13 with commit fc9c45b71f43cafcc0435dd4c7a2d3b99955a0fa and fixed in 6.13.7 with commit 91d011efe30aedde067ce6d218d521cf99b162e5
	Issue introduced in 6.13 with commit fc9c45b71f43cafcc0435dd4c7a2d3b99955a0fa and fixed in 6.14 with commit a564ccfe300fa6a065beda06ab7f3c140d6b4d63

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-2025-21933
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:
	arch/arm/mm/fault-armv.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/91d011efe30aedde067ce6d218d521cf99b162e5
	https://git.kernel.org/stable/c/a564ccfe300fa6a065beda06ab7f3c140d6b4d63