linux-cve-announce - CVE-2024-56599: wifi: ath10k: avoid NULL pointer error during sdio remove

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Message-ID: <2024122702-CVE-2024-56599-54af@gregkh>
Date: Fri, 27 Dec 2024 15:51:06 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2024-56599: wifi: ath10k: avoid NULL pointer error during sdio remove

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

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

wifi: ath10k: avoid NULL pointer error during sdio remove

When running 'rmmod ath10k', ath10k_sdio_remove() will free sdio
workqueue by destroy_workqueue(). But if CONFIG_INIT_ON_FREE_DEFAULT_ON
is set to yes, kernel panic will happen:
Call trace:
 destroy_workqueue+0x1c/0x258
 ath10k_sdio_remove+0x84/0x94
 sdio_bus_remove+0x50/0x16c
 device_release_driver_internal+0x188/0x25c
 device_driver_detach+0x20/0x2c

This is because during 'rmmod ath10k', ath10k_sdio_remove() will call
ath10k_core_destroy() before destroy_workqueue(). wiphy_dev_release()
will finally be called in ath10k_core_destroy(). This function will free
struct cfg80211_registered_device *rdev and all its members, including
wiphy, dev and the pointer of sdio workqueue. Then the pointer of sdio
workqueue will be set to NULL due to CONFIG_INIT_ON_FREE_DEFAULT_ON.

After device release, destroy_workqueue() will use NULL pointer then the
kernel panic happen.

Call trace:
ath10k_sdio_remove
  ->ath10k_core_unregister
    ……
    ->ath10k_core_stop
      ->ath10k_hif_stop
        ->ath10k_sdio_irq_disable
    ->ath10k_hif_power_down
      ->del_timer_sync(&ar_sdio->sleep_timer)
  ->ath10k_core_destroy
    ->ath10k_mac_destroy
      ->ieee80211_free_hw
        ->wiphy_free
    ……
          ->wiphy_dev_release
  ->destroy_workqueue

Need to call destroy_workqueue() before ath10k_core_destroy(), free
the work queue buffer first and then free pointer of work queue by
ath10k_core_destroy(). This order matches the error path order in
ath10k_sdio_probe().

No work will be queued on sdio workqueue between it is destroyed and
ath10k_core_destroy() is called. Based on the call_stack above, the
reason is:
Only ath10k_sdio_sleep_timer_handler(), ath10k_sdio_hif_tx_sg() and
ath10k_sdio_irq_disable() will queue work on sdio workqueue.
Sleep timer will be deleted before ath10k_core_destroy() in
ath10k_hif_power_down().
ath10k_sdio_irq_disable() only be called in ath10k_hif_stop().
ath10k_core_unregister() will call ath10k_hif_power_down() to stop hif
bus, so ath10k_sdio_hif_tx_sg() won't be called anymore.

Tested-on: QCA6174 hw3.2 SDIO WLAN.RMH.4.4.1-00189

The Linux kernel CVE team has assigned CVE-2024-56599 to this issue.

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

	Fixed in 6.12.5 with commit 543c0924d446b21f35701ca084d7feca09511220
	Fixed in 6.13-rc1 with commit 95c38953cb1ecf40399a676a1f85dfe2b5780a9a

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-2024-56599
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/net/wireless/ath/ath10k/sdio.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/543c0924d446b21f35701ca084d7feca09511220
	https://git.kernel.org/stable/c/95c38953cb1ecf40399a676a1f85dfe2b5780a9a