On Thu, Apr 28, 2022 at 04:31:10PM +0300, Ovidiu Panait wrote: > From: Lin Ma <linma@xxxxxxxxxx> > > commit 0b9111922b1f399aba6ed1e1b8f2079c3da1aed8 upstream. > > There is a possible race condition (use-after-free) like below > > (USE) | (FREE) > dev_queue_xmit | > __dev_queue_xmit | > __dev_xmit_skb | > sch_direct_xmit | ... > xmit_one | > netdev_start_xmit | tty_ldisc_kill > __netdev_start_xmit | 6pack_close > sp_xmit | kfree > sp_encaps | > | > > According to the patch "defer ax25 kfree after unregister_netdev", this > patch reorder the kfree after the unregister_netdev to avoid the possible > UAF as the unregister_netdev() is well synchronized and won't return if > there is a running routine. > > Signed-off-by: Lin Ma <linma@xxxxxxxxxx> > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> > Signed-off-by: Xu Jia <xujia39@xxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Ovidiu Panait <ovidiu.panait@xxxxxxxxxxxxx> > --- > These commits are part of CVE-2022-1195 patchset. > Reference: https://bugzilla.redhat.com/show_bug.cgi?id=2056381 > [1] https://github.com/torvalds/linux/commit/3e0588c291d6ce225f2b891753ca41d45ba42469 > [2] https://github.com/torvalds/linux/commit/b2f37aead1b82a770c48b5d583f35ec22aabb61e > [3] https://github.com/torvalds/linux/commit/0b9111922b1f399aba6ed1e1b8f2079c3da1aed8 > [4] https://github.com/torvalds/linux/commit/81b1d548d00bcd028303c4f3150fa753b9b8aa71 > > Commits [1] and [2] are already present in 5.4-stable, this patchset includes > backports for [3] and [4] (clean cherry-picks from 5.10 stable). > > drivers/net/hamradio/6pack.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c > index 02d6f3ad9aca..82507a688efe 100644 > --- a/drivers/net/hamradio/6pack.c > +++ b/drivers/net/hamradio/6pack.c > @@ -679,9 +679,11 @@ static void sixpack_close(struct tty_struct *tty) > del_timer_sync(&sp->tx_t); > del_timer_sync(&sp->resync_t); > > - /* Free all 6pack frame buffers. */ > + /* Free all 6pack frame buffers after unreg. */ > kfree(sp->rbuff); > kfree(sp->xbuff); > + > + free_netdev(sp->dev); > } > > /* Perform I/O control on an active 6pack channel. */ > -- > 2.36.0 > All backports now queued up, thanks! greg k-h
