From: Johan Hovold johan@kernel.org
stable inclusion from stable-v4.19.189 commit 5c17cfe155d21954b4c7e2a78fa771cebcd86725 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I93LMH CVE: CVE-2021-46904
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
---------------------------
commit 2ad5692db72874f02b9ad551d26345437ea4f7f3 upstream.
Commit 8a12f8836145 ("net: hso: fix null-ptr-deref during tty device unregistration") fixed the racy minor allocation reported by syzbot, but introduced an unconditional NULL-pointer dereference on every disconnect instead.
Specifically, the serial device table must no longer be accessed after the minor has been released by hso_serial_tty_unregister().
Fixes: 8a12f8836145 ("net: hso: fix null-ptr-deref during tty device unregistration") Cc: stable@vger.kernel.org Cc: Anirudh Rayabharam mail@anirudhrb.com Reported-by: Leonardo Antoniazzi leoanto@aruba.it Signed-off-by: Johan Hovold johan@kernel.org Reviewed-by: Anirudh Rayabharam mail@anirudhrb.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Liu Jian liujian56@huawei.com --- drivers/net/usb/hso.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c index 9a89089a6e08..160e3721fb48 100644 --- a/drivers/net/usb/hso.c +++ b/drivers/net/usb/hso.c @@ -3126,7 +3126,7 @@ static void hso_free_interface(struct usb_interface *interface) cancel_work_sync(&serial_table[i]->async_put_intf); cancel_work_sync(&serial_table[i]->async_get_intf); hso_serial_tty_unregister(serial); - kref_put(&serial_table[i]->ref, hso_serial_ref_free); + kref_put(&serial->parent->ref, hso_serial_ref_free); } }