Input: synaptics - avoid using uninitialized variable when probing
diff mbox series

Message ID 20181017001443.GA232819@dtor-ws
State New
Headers show
Series
  • Input: synaptics - avoid using uninitialized variable when probing
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Commit Message

Dmitry Torokhov Oct. 17, 2018, 12:14 a.m. UTC
synaptics_detect() does not check whether sending commands to the
device succeeds and instead relies on getting unique data from the
device. Let's make sure we seed entire buffer with zeroes to make sure
we not use garbage on stack that just happen to be 0x47.

Reported-by: syzbot+13cb3b01d0784e4ffc3f@syzkaller.appspotmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/mouse/synaptics.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

Comments

Benjamin Tissoires Oct. 17, 2018, 7:03 a.m. UTC | #1
On Wed, Oct 17, 2018 at 2:14 AM Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
>
> synaptics_detect() does not check whether sending commands to the
> device succeeds and instead relies on getting unique data from the
> device. Let's make sure we seed entire buffer with zeroes to make sure
> we not use garbage on stack that just happen to be 0x47.
>
> Reported-by: syzbot+13cb3b01d0784e4ffc3f@syzkaller.appspotmail.com
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Cheers,
Benjamin

>  drivers/input/mouse/synaptics.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> index 55d33500d55e..5e85f3cca867 100644
> --- a/drivers/input/mouse/synaptics.c
> +++ b/drivers/input/mouse/synaptics.c
> @@ -99,9 +99,7 @@ static int synaptics_mode_cmd(struct psmouse *psmouse, u8 mode)
>  int synaptics_detect(struct psmouse *psmouse, bool set_properties)
>  {
>         struct ps2dev *ps2dev = &psmouse->ps2dev;
> -       u8 param[4];
> -
> -       param[0] = 0;
> +       u8 param[4] = { 0 };
>
>         ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES);
>         ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES);
> --
> 2.19.1.331.ge82ca0e54c-goog
>
>
> --
> Dmitry
Peter Hutterer Oct. 19, 2018, 5:46 a.m. UTC | #2
On Tue, Oct 16, 2018 at 05:14:43PM -0700, Dmitry Torokhov wrote:
> synaptics_detect() does not check whether sending commands to the
> device succeeds and instead relies on getting unique data from the
> device. Let's make sure we seed entire buffer with zeroes to make sure
> we not use garbage on stack that just happen to be 0x47.
> 
> Reported-by: syzbot+13cb3b01d0784e4ffc3f@syzkaller.appspotmail.com
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

doh, was just about to send out the same patch.

Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

Cheers,
   Peter

> ---
>  drivers/input/mouse/synaptics.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> index 55d33500d55e..5e85f3cca867 100644
> --- a/drivers/input/mouse/synaptics.c
> +++ b/drivers/input/mouse/synaptics.c
> @@ -99,9 +99,7 @@ static int synaptics_mode_cmd(struct psmouse *psmouse, u8 mode)
>  int synaptics_detect(struct psmouse *psmouse, bool set_properties)
>  {
>  	struct ps2dev *ps2dev = &psmouse->ps2dev;
> -	u8 param[4];
> -
> -	param[0] = 0;
> +	u8 param[4] = { 0 };
>  
>  	ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES);
>  	ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES);
> -- 
> 2.19.1.331.ge82ca0e54c-goog
> 
> 
> -- 
> Dmitry

Patch
diff mbox series

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index 55d33500d55e..5e85f3cca867 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -99,9 +99,7 @@  static int synaptics_mode_cmd(struct psmouse *psmouse, u8 mode)
 int synaptics_detect(struct psmouse *psmouse, bool set_properties)
 {
 	struct ps2dev *ps2dev = &psmouse->ps2dev;
-	u8 param[4];
-
-	param[0] = 0;
+	u8 param[4] = { 0 };
 
 	ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES);
 	ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES);