Re: [PATCH v6 1/2] ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

Kalle Valo
2022-06-20T10:02:57Z

Pavel Skripkin <paskripkin@gmail.com> wrote:

> Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb() [0]. The
> problem was in incorrect htc_handle->drv_priv initialization.
>
> Probable call trace which can trigger use-after-free:
>
> ath9k_htc_probe_device()
> /* htc_handle->drv_priv = priv; */
> ath9k_htc_wait_for_target() <--- Failed
> ieee80211_free_hw() <--- priv pointer is freed
>
> <IRQ>
> ...
> ath9k_hif_usb_rx_cb()
> ath9k_hif_usb_rx_stream()
> RX_STAT_INC() <--- htc_handle->drv_priv access
>
> In order to not add fancy protection for drv_priv we can move
> htc_handle->drv_priv initialization at the end of the
> ath9k_htc_probe_device() and add helper macro to make
> all *_STAT_* macros NULL safe, since syzbot has reported related NULL
> deref in that macros [1]
>
> Link: https://syzkaller.appspot.com/bug?id=6ead44e37afb6866ac0c7dd121b4ce07cb665f60 [0]
> Link: https://syzkaller.appspot.com/bug?id=b8101ffcec107c0567a0cd8acbbacec91e9ee8de [1]
> Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
> Reported-and-tested-by: syzbot+03110230a11411024147@syzkaller.appspotmail.com
> Reported-and-tested-by: syzbot+c6dde1f690b60e0b9fbe@syzkaller.appspotmail.com
> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

2 patches applied to ath-next branch of ath.git, thanks.

0ac4827f78c7 ath9k: fix use-after-free in ath9k_hif_usb_rx_cb
d7fc76039b74 ath9k: htc: clean up statistics macros

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