4.20-stable review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan@kernel.org
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 stable@vger.kernel.org # 4.13 Cc: Okash Khawaja okash.khawaja@gmail.com Cc: Samuel Thibault samuel.thibault@ens-lyon.org Signed-off-by: Johan Hovold johan@kernel.org Reviewed-by: Samuel Thibault samuel.thibault@ens-lyon.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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 @@ -265,7 +265,8 @@ 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); }
@@ -277,7 +278,8 @@ 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); }