1. 29 Jan, 2020 1 commit
    • Richard Palethorpe's avatar
      can, slip: Protect tty->disc_data in write_wakeup and close with RCU · bd144845
      Richard Palethorpe authored
      [ Upstream commit 0ace17d5 ]
      
      write_wakeup can happen in parallel with close/hangup where tty->disc_data
      is set to NULL and the netdevice is freed thus also freeing
      disc_data. write_wakeup accesses disc_data so we must prevent close from
      freeing the netdev while write_wakeup has a non-NULL view of
      tty->disc_data.
      
      We also need to make sure that accesses to disc_data are atomic. Which can
      all be done with RCU.
      
      This problem was found by Syzkaller on SLCAN, but the same issue is
      reproducible with the SLIP line discipline using an LTP test based on the
      Syzkaller reproducer.
      
      A fix which didn't use RCU was posted by Hillf Danton.
      
      Fixes: 661f7fda ("slip: Fix deadlock in write_wakeup")
      Fixes: a8e83b17 ("slcan: Port write_wakeup deadlock fix from slip")
      Reported-by: syzbot+017e491ae13c0068598a@syzkaller.appspotmail.com
      Signed-off-by: default avatarRichard Palethorpe <rpalethorpe@suse.com>
      Cc: Wolfgang Grandegger <wg@grandegger.com>
      Cc: Marc Kleine-Budde <mkl@pengutronix.de>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Tyler Hall <tylerwhall@gmail.com>
      Cc: linux-can@vger.kernel.org
      Cc: netdev@vger.kernel.org
      Cc: linux-kernel@vger.kernel.org
      Cc: syzkaller@googlegroups.com
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      bd144845
  2. 27 Jan, 2020 39 commits