On Wed, 15 Jun 2022 11:05:20 +0200, Toke Høiland-Jørgensen wrote: > > Kalle Valo <kvalo@xxxxxxxxxx> writes: > > > Toke Høiland-Jørgensen <toke@xxxxxxx> writes: > > > >> Pavel Skripkin <paskripkin@xxxxxxxxx> writes: > >> > >>> 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@xxxxxxxxxxxxxxxxxxxxxxxxx > >>> Reported-and-tested-by: syzbot+c6dde1f690b60e0b9fbe@xxxxxxxxxxxxxxxxxxxxxxxxx > >>> Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx> > >> > >> Alright, since we've heard no more objections and the status quo is > >> definitely broken, let's get this merged and we can follow up with any > >> other fixes as necessary... > >> > >> Acked-by: Toke Høiland-Jørgensen <toke@xxxxxxx> > > > > I'm wondering should these go to -rc or -next? Has anyone actually > > tested these with real hardware? (syzbot testing does not count) With > > the past bad experience with syzbot fixes I'm leaning towards -next to > > have more time to fix any regressions. > > Hmm, good question. From Takashi's comment on v5, it seems like distros > are going to backport it anyway, so in that sense it probably doesn't > matter that much? Well, it does matter if it really breaks things, of course ;) > In any case I think it has a fairly low probability of breaking real > users' setup (how often is that error path on setup even hit?), but I'm > OK with it going to -next to be doubleplus-sure :) Queuing to for-next is fine for us. Backporting immediately or not will be a decision by each distro, then. OTOH, if anyone has tested it beforehand on a real hardware and confirmed, at least, that it works for normal cases (no error path), that should suffice for -rc inclusion, too, IMO. thanks, Takashi
