4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Johan Hovold <[email protected]> commit a1960e0f1639cb1f7a3d94521760fc73091f6640 upstream. The send_xchar() and tiocmset() tty operations are optional. Add the missing sanity checks to prevent user-space triggerable NULL-pointer dereferences. Fixes: 6b9ad1c742bf ("staging: speakup: add send_xchar, tiocmset and input functionality for tty") Cc: stable <[email protected]> # 4.13 Cc: Okash Khawaja <[email protected]> Cc: Samuel Thibault <[email protected]> Signed-off-by: Johan Hovold <[email protected]> Reviewed-by: Samuel Thibault <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/staging/speakup/spk_ttyio.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/staging/speakup/spk_ttyio.c +++ b/drivers/staging/speakup/spk_ttyio.c @@ -246,7 +246,8 @@ static void spk_ttyio_send_xchar(char ch return; } - speakup_tty->ops->send_xchar(speakup_tty, ch); + if (speakup_tty->ops->send_xchar) + speakup_tty->ops->send_xchar(speakup_tty, ch); mutex_unlock(&speakup_tty_mutex); } @@ -258,7 +259,8 @@ static void spk_ttyio_tiocmset(unsigned return; } - speakup_tty->ops->tiocmset(speakup_tty, set, clear); + if (speakup_tty->ops->tiocmset) + speakup_tty->ops->tiocmset(speakup_tty, set, clear); mutex_unlock(&speakup_tty_mutex); }
