Re: [PATCH v5 1/2] ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

Toke Høiland-Jørgensen
2022-06-10T18:30:43Z

Takashi Iwai <tiwai@suse.de> writes:

> On Sat, 21 May 2022 23:28:01 +0200,
> Pavel Skripkin 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>
>
> Hi Toke, any update on this?

It's marked as "Changes Requested" in patchwork, due to the kernel test
robot comments on patch 2[0]. So it's waiting for Pavel to resubmit
fixing that. There's also a separate comment on patch 1, which I just
noticed didn't have the mailing list in Cc; will reply to that and try
to get it back on the list.

> I'm asking it because this is a fix for a security issue
> (CVE-2022-1679 [*]), and distros have been waiting for the fix getting
> merged to the upstream for weeks.
>
> [*] https://nvd.nist.gov/vuln/detail/CVE-2022-1679

In general, if a patch is marked as "changes requested", the right thing
to do is to bug the submitter to resubmit. Which I guess you just did,
so hopefully we'll get an update soon :)

-Toke

[0] https://patchwork.kernel.org/project/linux-wireless/patch/7bb006bb88e280c596d0e86ece7d251a21b8ed1f.1653168225.git.paskripkin@gmail.com/