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Commit a1960e0f authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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staging: speakup: fix tty-operation NULL derefs 



The send_xchar() and tiocmset() tty operations are optional. Add the
missing sanity checks to prevent user-space triggerable NULL-pointer
dereferences.

Fixes: 6b9ad1c7 ("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: default avatarJohan Hovold <johan@kernel.org>
Reviewed-by: default avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4d95987a

drivers/staging/speakup/spk_ttyio.c

+4 −2
Original line number Diff line number Diff line
@@ -265,6 +265,7 @@ static void spk_ttyio_send_xchar(char ch) 
		return;

	}



	if (speakup_tty->ops->send_xchar)

		speakup_tty->ops->send_xchar(speakup_tty, ch);

	mutex_unlock(&speakup_tty_mutex);

}
@@ -277,6 +278,7 @@ static void spk_ttyio_tiocmset(unsigned int set, unsigned int clear) 
		return;

	}



	if (speakup_tty->ops->tiocmset)

		speakup_tty->ops->tiocmset(speakup_tty, set, clear);

	mutex_unlock(&speakup_tty_mutex);

}