diff mbox series

HID: steelseries: Fix signedness bug in steelseries_headset_arctis_1_fetch_battery()

Message ID 5c1cc882-b2b8-45cb-b8f7-4b35d1800e5d@moroto.mountain
State Accepted
Commit 6c667ef6e2c88523469a6a94493b441cac2970d9
Headers show
Series HID: steelseries: Fix signedness bug in steelseries_headset_arctis_1_fetch_battery() | expand

Commit Message

Dan Carpenter Sept. 7, 2023, 9:55 a.m. UTC
The hid_hw_raw_request() function returns negative error codes or the
number bytes transferred.  If it returns negative error codes, then the
problem is that when we check if "ret < sizeof(arctis_1_battery_request)",
negative values are type promoted to high unsigned values and treated as
success.  Add an explicit check for negatives to address this issue.

Fixes: a0c76896c3fb ("HID: steelseries: Add support for Arctis 1 XBox")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
 drivers/hid/hid-steelseries.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Bastien Nocera Sept. 13, 2023, 2:43 p.m. UTC | #1
Hey Dan,

On Thu, 2023-09-07 at 12:55 +0300, Dan Carpenter wrote:
> The hid_hw_raw_request() function returns negative error codes or the
> number bytes transferred.  If it returns negative error codes, then
> the
> problem is that when we check if "ret <
> sizeof(arctis_1_battery_request)",
> negative values are type promoted to high unsigned values and treated
> as
> success.  Add an explicit check for negatives to address this issue.

I would be grateful if you could either add the compiler's error
message or explain in greater details the integer type promotion (or
demotion from signed to unsigned in this case) in the commit message.

> Fixes: a0c76896c3fb ("HID: steelseries: Add support for Arctis 1
> XBox")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>



> ---
>  drivers/hid/hid-steelseries.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hid/hid-steelseries.c b/drivers/hid/hid-
> steelseries.c
> index 43d2cf7153d7..485d2287d58a 100644
> --- a/drivers/hid/hid-steelseries.c
> +++ b/drivers/hid/hid-steelseries.c
> @@ -390,7 +390,7 @@ static int
> steelseries_headset_arctis_1_fetch_battery(struct hid_device *hdev)
>         ret = hid_hw_raw_request(hdev, arctis_1_battery_request[0],
>                                  write_buf,
> sizeof(arctis_1_battery_request),
>                                  HID_OUTPUT_REPORT,
> HID_REQ_SET_REPORT);
> -       if (ret < sizeof(arctis_1_battery_request)) {
> +       if (ret < 0 || ret < sizeof(arctis_1_battery_request)) {

I prefer:
-       if (ret < sizeof(arctis_1_battery_request)) {
+       if (ret < (int) sizeof(arctis_1_battery_request)) {

although I'm not sure that's the kernel-style for this sort of checks.

>                 hid_err(hdev, "hid_hw_raw_request() failed with
> %d\n", ret);
>                 ret = -ENODATA;
>         }
Bastien Nocera Sept. 13, 2023, 7:06 p.m. UTC | #2
On Wed, 2023-09-13 at 20:38 +0300, Dan Carpenter wrote:
> On Wed, Sep 13, 2023 at 04:43:29PM +0200, Bastien Nocera wrote:
> > Hey Dan,
> > 
> > On Thu, 2023-09-07 at 12:55 +0300, Dan Carpenter wrote:
> > > The hid_hw_raw_request() function returns negative error codes or
> > > the
> > > number bytes transferred.  If it returns negative error codes,
> > > then
> > > the
> > > problem is that when we check if "ret <
> > > sizeof(arctis_1_battery_request)",
> > > negative values are type promoted to high unsigned values and
> > > treated
> > > as
> > > success.  Add an explicit check for negatives to address this
> > > issue.
> > 
> > I would be grateful if you could either add the compiler's error
> > message or explain in greater details the integer type promotion
> > (or
> > demotion from signed to unsigned in this case) in the commit
> > message.
> > 
> 
> This is a Smatch warning but you have to have built the cross
> function
> database and I only know one other person who does that for sure...
> 
> drivers/hid/hid-steelseries.c:393
> steelseries_headset_arctis_1_fetch_battery()
> warn: error code type promoted to positive: 'ret'
> 
> I can add that and resend.

That would be great, thanks!

> 
> > > Fixes: a0c76896c3fb ("HID: steelseries: Add support for Arctis 1
> > > XBox")
> > > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> > 
> > 
> > 
> > > ---
> > >  drivers/hid/hid-steelseries.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/hid/hid-steelseries.c b/drivers/hid/hid-
> > > steelseries.c
> > > index 43d2cf7153d7..485d2287d58a 100644
> > > --- a/drivers/hid/hid-steelseries.c
> > > +++ b/drivers/hid/hid-steelseries.c
> > > @@ -390,7 +390,7 @@ static int
> > > steelseries_headset_arctis_1_fetch_battery(struct hid_device
> > > *hdev)
> > >         ret = hid_hw_raw_request(hdev,
> > > arctis_1_battery_request[0],
> > >                                  write_buf,
> > > sizeof(arctis_1_battery_request),
> > >                                  HID_OUTPUT_REPORT,
> > > HID_REQ_SET_REPORT);
> > > -       if (ret < sizeof(arctis_1_battery_request)) {
> > > +       if (ret < 0 || ret < sizeof(arctis_1_battery_request)) {
> > 
> > I prefer:
> > -       if (ret < sizeof(arctis_1_battery_request)) {
> > +       if (ret < (int) sizeof(arctis_1_battery_request)) {
> > 
> > although I'm not sure that's the kernel-style for this sort of
> > checks.
> > 
> 
> I grepped to see which format is more popular and it's 14 vs 13 in
> favor
> of casting.  I prefer to avoid casts, but I can resend.
> 
> regards,
> dan carpenter
> 
>
diff mbox series

Patch

diff --git a/drivers/hid/hid-steelseries.c b/drivers/hid/hid-steelseries.c
index 43d2cf7153d7..485d2287d58a 100644
--- a/drivers/hid/hid-steelseries.c
+++ b/drivers/hid/hid-steelseries.c
@@ -390,7 +390,7 @@  static int steelseries_headset_arctis_1_fetch_battery(struct hid_device *hdev)
 	ret = hid_hw_raw_request(hdev, arctis_1_battery_request[0],
 				 write_buf, sizeof(arctis_1_battery_request),
 				 HID_OUTPUT_REPORT, HID_REQ_SET_REPORT);
-	if (ret < sizeof(arctis_1_battery_request)) {
+	if (ret < 0 || ret < sizeof(arctis_1_battery_request)) {
 		hid_err(hdev, "hid_hw_raw_request() failed with %d\n", ret);
 		ret = -ENODATA;
 	}