linux-cve-announce - CVE-2023-53256: firmware: arm_ffa: Fix FFA device names for logical partitions

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Message-ID: <2025091503-CVE-2023-53256-d5af@gregkh>
Date: Mon, 15 Sep 2025 16:46:31 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53256: firmware: arm_ffa: Fix FFA device names for logical partitions

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

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

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

firmware: arm_ffa: Fix FFA device names for logical partitions

Each physical partition can provide multiple services each with UUID.
Each such service can be presented as logical partition with a unique
combination of VM ID and UUID. The number of distinct UUID in a system
will be less than or equal to the number of logical partitions.

However, currently it fails to register more than one logical partition
or service within a physical partition as the device name contains only
VM ID while both VM ID and UUID are maintained in the partition information.
The kernel complains with the below message:

  | sysfs: cannot create duplicate filename '/devices/arm-ffa-8001'
  | CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.3.0-rc7 #8
  | Hardware name: FVP Base RevC (DT)
  | Call trace:
  |  dump_backtrace+0xf8/0x118
  |  show_stack+0x18/0x24
  |  dump_stack_lvl+0x50/0x68
  |  dump_stack+0x18/0x24
  |  sysfs_create_dir_ns+0xe0/0x13c
  |  kobject_add_internal+0x220/0x3d4
  |  kobject_add+0x94/0x100
  |  device_add+0x144/0x5d8
  |  device_register+0x20/0x30
  |  ffa_device_register+0x88/0xd8
  |  ffa_setup_partitions+0x108/0x1b8
  |  ffa_init+0x2ec/0x3a4
  |  do_one_initcall+0xcc/0x240
  |  do_initcall_level+0x8c/0xac
  |  do_initcalls+0x54/0x94
  |  do_basic_setup+0x1c/0x28
  |  kernel_init_freeable+0x100/0x16c
  |  kernel_init+0x20/0x1a0
  |  ret_from_fork+0x10/0x20
  | kobject_add_internal failed for arm-ffa-8001 with -EEXIST, don't try to
  | register things with the same name in the same directory.
  | arm_ffa arm-ffa: unable to register device arm-ffa-8001 err=-17
  | ARM FF-A: ffa_setup_partitions: failed to register partition ID 0x8001

By virtue of being random enough to avoid collisions when generated in a
distributed system, there is no way to compress UUID keys to the number
of bits required to identify each. We can eliminate '-' in the name but
it is not worth eliminating 4 bytes and add unnecessary logic for doing
that. Also v1.0 doesn't provide the UUID of the partitions which makes
it hard to use the same for the device name.

So to keep it simple, let us alloc an ID using ida_alloc() and append the
same to "arm-ffa" to make up a unique device name. Also stash the id value
in ffa_dev to help freeing the ID later when the device is destroyed.

The Linux kernel CVE team has assigned CVE-2023-53256 to this issue.


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

	Issue introduced in 5.14 with commit e781858488b918e30a6ff28e9eab6058b787e3b3 and fixed in 5.15.114 with commit c2f65991097a62efbdb2bed3c06fc86b08c9593b
	Issue introduced in 5.14 with commit e781858488b918e30a6ff28e9eab6058b787e3b3 and fixed in 6.1.31 with commit dfc5aaa57f52a5800c339369d235fa30fb734feb
	Issue introduced in 5.14 with commit e781858488b918e30a6ff28e9eab6058b787e3b3 and fixed in 6.3.5 with commit 93d0cbe88118fcef234d3ebcbdadcb9ebe9d34f1
	Issue introduced in 5.14 with commit e781858488b918e30a6ff28e9eab6058b787e3b3 and fixed in 6.4 with commit 19b8766459c41c6f318f8a548cc1c66dffd18363

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-2023-53256
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:
	drivers/firmware/arm_ffa/bus.c
	include/linux/arm_ffa.h


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/c2f65991097a62efbdb2bed3c06fc86b08c9593b
	https://git.kernel.org/stable/c/dfc5aaa57f52a5800c339369d235fa30fb734feb
	https://git.kernel.org/stable/c/93d0cbe88118fcef234d3ebcbdadcb9ebe9d34f1
	https://git.kernel.org/stable/c/19b8766459c41c6f318f8a548cc1c66dffd18363