Messages in this thread | | | Date | Thu, 12 May 2022 15:55:59 +0300 | Subject | Re: [PATCH v3 1/2] ath9k: fix use-after-free in ath9k_hif_usb_rx_cb | From | Pavel Skripkin <> |
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Hi Toke,
On 5/12/22 15:49, Toke Høiland-Jørgensen wrote: > Pavel Skripkin <paskripkin@gmail.com> writes: > >> Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb(). 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 save. >> >> 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> > > Could you link the original syzbot report in the commit message as well,
Sure! See links below
use-after-free bug: https://syzkaller.appspot.com/bug?id=6ead44e37afb6866ac0c7dd121b4ce07cb665f60
NULL deref bug: https://syzkaller.appspot.com/bug?id=b8101ffcec107c0567a0cd8acbbacec91e9ee8de
I can add them in commit message if you want :)
> please? Also that 'tested-by' implies that syzbot run-tested this? How > does it do that; does it have ath9k_htc hardware? >
No, it uses CONFIG_USB_RAW_GADGET and CONFIG_USB_DUMMY_HCD for gadgets for emulating usb devices.
Basically these things "connect" fake USB device with random usb ids from hardcoded table and try to do various things with usb driver
>> ---
[snip]
>> -#define TX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c++) >> -#define TX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a) >> -#define RX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++) >> -#define RX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a) >> +#define __STAT_SAVE(expr) (hif_dev->htc_handle->drv_priv ? (expr) : 0) >> +#define TX_STAT_INC(c) __STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c++) >> +#define TX_STAT_ADD(c, a) __STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a) >> +#define RX_STAT_INC(c) __STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++) >> +#define RX_STAT_ADD(c, a) __STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a) >> #define CAB_STAT_INC priv->debug.tx_stats.cab_queued++ > > s/SAVE/SAFE/ here and in the next patch (and the commit message). >
Oh, sorry about that! Will update in next version
With regards, Pavel Skripkin [unhandled content-type:application/pgp-signature] | |