Re: [PATCH] platform/x86: asus-wmi: Fix NULL pointer dereference

[Andy Shevchenko]

On Wed, May 23, 2018 at 12:30 AM, JoÃo Paulo Rechi Vita
<jprvita@xxxxxxxxx> wrote:
> Do not perform the rfkill cleanup routine when
> (asus->driver->wlan_ctrl_by_user && ashs_present()) is true, since
> nothing is registered with the rfkill subsystem in that case. Doing so
> leads to the following kernel NULL pointer dereference:
>
>   BUG: unable to handle kernel NULL pointer dereference at           (null)
>   IP: [<ffffffff816c7348>] __mutex_lock_slowpath+0x98/0x120
>   PGD 1a3aa8067
>   PUD 1a3b3d067
>   PMD 0
>
>   Oops: 0002 [#1] PREEMPT SMP
>   Modules linked in: bnep ccm binfmt_misc uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core hid_a4tech videodev x86_pkg_temp_thermal intel_powerclamp coretemp ath3k btusb btrtl btintel bluetooth kvm_intel snd_hda_codec_hdmi kvm snd_hda_codec_realtek snd_hda_codec_generic irqbypass crc32c_intel arc4 i915 snd_hda_intel snd_hda_codec ath9k ath9k_common ath9k_hw ath i2c_algo_bit snd_hwdep mac80211 ghash_clmulni_intel snd_hda_core snd_pcm snd_timer cfg80211 ehci_pci xhci_pci drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm xhci_hcd ehci_hcd asus_nb_wmi(-) asus_wmi sparse_keymap r8169 rfkill mxm_wmi serio_raw snd mii mei_me lpc_ich i2c_i801 video soundcore mei i2c_smbus wmi i2c_core mfd_core
>   CPU: 3 PID: 3275 Comm: modprobe Not tainted 4.9.34-gentoo #34
>   Hardware name: ASUSTeK COMPUTER INC. K56CM/K56CM, BIOS K56CM.206 08/21/2012
>   task: ffff8801a639ba00 task.stack: ffffc900014cc000
>   RIP: 0010:[<ffffffff816c7348>]  [<ffffffff816c7348>] __mutex_lock_slowpath+0x98/0x120
>   RSP: 0018:ffffc900014cfce0  EFLAGS: 00010282
>   RAX: 0000000000000000 RBX: ffff8801a54315b0 RCX: 00000000c0000100
>   RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8801a54315b4
>   RBP: ffffc900014cfd30 R08: 0000000000000000 R09: 0000000000000002
>   R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801a54315b4
>   R13: ffff8801a639ba00 R14: 00000000ffffffff R15: ffff8801a54315b8
>   FS:  00007faa254fb700(0000) GS:ffff8801aef80000(0000) knlGS:0000000000000000
>   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>   CR2: 0000000000000000 CR3: 00000001a3b1b000 CR4: 00000000001406e0
>   Stack:
>    ffff8801a54315b8 0000000000000000 ffffffff814733ae ffffc900014cfd28
>    ffffffff8146a28c ffff8801a54315b0 0000000000000000 ffff8801a54315b0
>    ffff8801a66f3820 0000000000000000 ffffc900014cfd48 ffffffff816c73e7
>   Call Trace:
>    [<ffffffff814733ae>] ? acpi_ut_release_mutex+0x5d/0x61
>    [<ffffffff8146a28c>] ? acpi_ns_get_node+0x49/0x52
>    [<ffffffff816c73e7>] mutex_lock+0x17/0x30
>    [<ffffffffa00a3bb4>] asus_rfkill_hotplug+0x24/0x1a0 [asus_wmi]
>    [<ffffffffa00a4421>] asus_wmi_rfkill_exit+0x61/0x150 [asus_wmi]
>    [<ffffffffa00a49f1>] asus_wmi_remove+0x61/0xb0 [asus_wmi]
>    [<ffffffff814a5128>] platform_drv_remove+0x28/0x40
>    [<ffffffff814a2901>] __device_release_driver+0xa1/0x160
>    [<ffffffff814a29e3>] device_release_driver+0x23/0x30
>    [<ffffffff814a1ffd>] bus_remove_device+0xfd/0x170
>    [<ffffffff8149e5a9>] device_del+0x139/0x270
>    [<ffffffff814a5028>] platform_device_del+0x28/0x90
>    [<ffffffff814a50a2>] platform_device_unregister+0x12/0x30
>    [<ffffffffa00a4209>] asus_wmi_unregister_driver+0x19/0x30 [asus_wmi]
>    [<ffffffffa00da0ea>] asus_nb_wmi_exit+0x10/0xf26 [asus_nb_wmi]
>    [<ffffffff8110c692>] SyS_delete_module+0x192/0x270
>    [<ffffffff810022b2>] ? exit_to_usermode_loop+0x92/0xa0
>    [<ffffffff816ca560>] entry_SYSCALL_64_fastpath+0x13/0x94
>   Code: e8 5e 30 00 00 8b 03 83 f8 01 0f 84 93 00 00 00 48 8b 43 10 4c 8d 7b 08 48 89 63 10 41 be ff ff ff ff 4c 89 3c 24 48 89 44 24 08 <48> 89 20 4c 89 6c 24 10 eb 1d 4c 89 e7 49 c7 45 08 02 00 00 00
>   RIP  [<ffffffff816c7348>] __mutex_lock_slowpath+0x98/0x120
>    RSP <ffffc900014cfce0>
>   CR2: 0000000000000000
>   ---[ end trace 8d484233fa7cb512 ]---
>   note: modprobe[3275] exited with preempt_count 2
>
> https://bugzilla.kernel.org/show_bug.cgi?id=196467
>

Pushed to my review and testing queue with asap promotion to fixes, thanks!

> Reported-by: red.f0xyz@xxxxxxxxx
> Signed-off-by: JoÃo Paulo Rechi Vita <jprvita@xxxxxxxxxxxx>
> ---
>  drivers/platform/x86/asus-wmi.c | 23 +++++++++++++----------
>  1 file changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index ef87e78ca772..3d523ca64694 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -163,6 +163,16 @@ MODULE_LICENSE("GPL");
>
>  static const char * const ashs_ids[] = { "ATK4001", "ATK4002", NULL };
>
> +static bool ashs_present(void)
> +{
> +       int i = 0;
> +       while (ashs_ids[i]) {
> +               if (acpi_dev_found(ashs_ids[i++]))
> +                       return true;
> +       }
> +       return false;
> +}
> +
>  struct bios_args {
>         u32 arg0;
>         u32 arg1;
> @@ -1025,6 +1035,9 @@ static int asus_new_rfkill(struct asus_wmi *asus,
>
>  static void asus_wmi_rfkill_exit(struct asus_wmi *asus)
>  {
> +       if (asus->driver->wlan_ctrl_by_user && ashs_present())
> +               return;
> +
>         asus_unregister_rfkill_notifier(asus, "\\_SB.PCI0.P0P5");
>         asus_unregister_rfkill_notifier(asus, "\\_SB.PCI0.P0P6");
>         asus_unregister_rfkill_notifier(asus, "\\_SB.PCI0.P0P7");
> @@ -2120,16 +2133,6 @@ static int asus_wmi_fan_init(struct asus_wmi *asus)
>         return 0;
>  }
>
> -static bool ashs_present(void)
> -{
> -       int i = 0;
> -       while (ashs_ids[i]) {
> -               if (acpi_dev_found(ashs_ids[i++]))
> -                       return true;
> -       }
> -       return false;
> -}
> -
>  /*
>   * WMI Driver
>   */
> --
> 2.17.0
>



-- 
With Best Regards,
Andy Shevchenko