Re: [PATCH] ar5523: Fix null-ptr-deref with unexpected WDCMSG_TARGET_START reply

[Kalle Valo]

Zekun Shen <bruceshenzk@xxxxxxxxx> wrote:

> Unexpected WDCMSG_TARGET_START replay can lead to null-ptr-deref
> when ar->tx_cmd->odata is NULL. The patch adds a null check to
> prevent such case.
> 
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
>  ar5523_cmd+0x46a/0x581 [ar5523]
>  ar5523_probe.cold+0x1b7/0x18da [ar5523]
>  ? ar5523_cmd_rx_cb+0x7a0/0x7a0 [ar5523]
>  ? __pm_runtime_set_status+0x54a/0x8f0
>  ? _raw_spin_trylock_bh+0x120/0x120
>  ? pm_runtime_barrier+0x220/0x220
>  ? __pm_runtime_resume+0xb1/0xf0
>  usb_probe_interface+0x25b/0x710
>  really_probe+0x209/0x5d0
>  driver_probe_device+0xc6/0x1b0
>  device_driver_attach+0xe2/0x120
> 
> I found the bug using a custome USBFuzz port. It's a research work
> to fuzz USB stack/drivers. I modified it to fuzz ath9k driver only,
> providing hand-crafted usb descriptors to QEMU.
> 
> After fixing the code (fourth byte in usb packet) to WDCMSG_TARGET_START,
> I got the null-ptr-deref bug. I believe the bug is triggerable whenever
> cmd->odata is NULL. After patching, I tested with the same input and no
> longer see the KASAN report.
> 
> This was NOT tested on a real device.
> 
> Signed-off-by: Zekun Shen <bruceshenzk@xxxxxxxxx>
> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>

Patch applied to ath-next branch of ath.git, thanks.

ae80b6033834 ar5523: Fix null-ptr-deref with unexpected WDCMSG_TARGET_START reply

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/YXsmPQ3awHFLuAj2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches