linux-kernel - Re: [PATCH RESEND v2] ASoC: SOF: Intel: hda: Fix UAF when reloading module

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

Message-ID: <7637e816-8c63-4e95-98fc-aea6a4843391@linux.intel.com>
Date: Wed, 7 May 2025 10:33:15 +0300
From: Péter Ujfalusi <peter.ujfalusi@...ux.intel.com>
To: Tavian Barnes <tavianator@...ianator.com>, linux-sound@...r.kernel.org
Cc: Liam Girdwood <lgirdwood@...il.com>,
 Bard Liao <yung-chuan.liao@...ux.intel.com>,
 Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
 Daniel Baluta <daniel.baluta@....com>,
 Kai Vehmanen <kai.vehmanen@...ux.intel.com>,
 Pierre-Louis Bossart <pierre-louis.bossart@...ux.dev>,
 Mark Brown <broonie@...nel.org>, Jaroslav Kysela <perex@...ex.cz>,
 Takashi Iwai <tiwai@...e.com>, Brent Lu <brent.lu@...el.com>,
 Peter Zijlstra <peterz@...radead.org>, sound-open-firmware@...a-project.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH RESEND v2] ASoC: SOF: Intel: hda: Fix UAF when reloading
 module



On 06/05/2025 18:12, Tavian Barnes wrote:
> hda_generic_machine_select() appends -idisp to the tplg filename by
> allocating a new string with devm_kasprintf(), then stores the string
> right back into the global variable snd_soc_acpi_intel_hda_machines.
> When the module is unloaded, this memory is freed, resulting in a global
> variable pointing to freed memory.  Reloading the modules then triggers
> a use-after-free:
> 
> BUG: KFENCE: use-after-free read in string+0x48/0xe0
> 
> Use-after-free read at 0x00000000967e0109 (in kfence-#99):
>  string+0x48/0xe0
>  vsnprintf+0x329/0x6e0
>  devm_kvasprintf+0x54/0xb0
>  devm_kasprintf+0x58/0x80
>  hda_machine_select.cold+0x198/0x17a2 [snd_sof_intel_hda_generic]
>  sof_probe_work+0x7f/0x600 [snd_sof]
>  process_one_work+0x17b/0x330
>  worker_thread+0x2ce/0x3f0
>  kthread+0xcf/0x100
>  ret_from_fork+0x31/0x50
>  ret_from_fork_asm+0x1a/0x30
> 
> kfence-#99: 0x00000000198a940f-0x00000000ace47d9d, size=64, cache=kmalloc-64
> 
> allocated by task 333 on cpu 8 at 17.798069s (130.453553s ago):
>  devm_kmalloc+0x52/0x120
>  devm_kvasprintf+0x66/0xb0
>  devm_kasprintf+0x58/0x80
>  hda_machine_select.cold+0x198/0x17a2 [snd_sof_intel_hda_generic]
>  sof_probe_work+0x7f/0x600 [snd_sof]
>  process_one_work+0x17b/0x330
>  worker_thread+0x2ce/0x3f0
>  kthread+0xcf/0x100
>  ret_from_fork+0x31/0x50
>  ret_from_fork_asm+0x1a/0x30
> 
> freed by task 1543 on cpu 4 at 141.586686s (6.665010s ago):
>  release_nodes+0x43/0xb0
>  devres_release_all+0x90/0xf0
>  device_unbind_cleanup+0xe/0x70
>  device_release_driver_internal+0x1c1/0x200
>  driver_detach+0x48/0x90
>  bus_remove_driver+0x6d/0xf0
>  pci_unregister_driver+0x42/0xb0
>  __do_sys_delete_module+0x1d1/0x310
>  do_syscall_64+0x82/0x190
>  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> 
> Fix it by saving the filename in pdata->tplg_filename instead, just like
> every other code path that appends to the tplg filename.
> 
> Fixes: 5458411d7594 ("ASoC: SOF: Intel: hda: refactoring topology name fixup for HDA mach")
> Signed-off-by: Tavian Barnes <tavianator@...ianator.com>
> ---
> v2: Fix typo
> 
>  sound/soc/sof/intel/hda.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/sof/intel/hda.c b/sound/soc/sof/intel/hda.c
> index b34e5fdf10f1..1767977e7cff 100644
> --- a/sound/soc/sof/intel/hda.c
> +++ b/sound/soc/sof/intel/hda.c
> @@ -1069,7 +1069,7 @@ static void hda_generic_machine_select(struct snd_sof_dev *sdev,
>  				if (!tplg_filename)
>  					return;
>  
> -				hda_mach->sof_tplg_filename = tplg_filename;
> +				pdata->tplg_filename = tplg_filename;
>  			}
>  
>  			if (codec_num == 2 ||

I think the correct way would be to make a local copy of the
snd_soc_acpi_intel_hda_machines array as we might be modifying it:


/*
 * make a local copy of the match array since we might
 * be modifying it
 */
hda_mach = devm_kmemdup_array(sdev->dev,
		snd_soc_acpi_intel_hda_machines,
		2 /* we have one entry + sentinel in the array */,
		sizeof(snd_soc_acpi_intel_hda_machines[0]),
		GFP_KERNEL);
if (!hda_mach) {
	dev_err(bus->dev,
		"%s: Failed to duplicate the HDA match table\n",
		__func__);
	return;
}

or if the "2" is not satisfactory (we _know_ that the array size is 2
for this and will not change):
include/sound/soc-acpi-intel-match.h
+extern size_t snd_soc_acpi_num_intel_hda_machines;

sound/soc/intel/common/soc-acpi-intel-hda-match.c
+size_t snd_soc_acpi_num_intel_hda_machines =
ARRAY_SIZE(snd_soc_acpi_intel_hda_machines);
+EXPORT_SYMBOL_GPL(snd_soc_acpi_num_intel_hda_machines);

and:
/*
 * make a local copy of the match array since we might
 * be modifying it
 */
hda_mach = devm_kmemdup_array(sdev->dev,
		snd_soc_acpi_intel_hda_machines,
		snd_soc_acpi_num_intel_hda_machines,
		sizeof(snd_soc_acpi_intel_hda_machines[0]),
		GFP_KERNEL);
if (!hda_mach) {
	dev_err(bus->dev,
		"%s: Failed to duplicate the HDA match table\n",
		__func__);
	return;
}



-- 
Péter