gpio: gpio-xilinx: Fix integer overflow

[PATCH] gpio: gpio-xilinx: Fix integer overflow

Posted by Srinivas Neeli 3 years, 9 months ago

Current implementation is not able to configure more than 32 pins
due to incorrect data type. So type casting with unsigned long
to avoid it.

Fixes: 02b3f84d9080 ("xilinx: Switch to use bitmap APIs")
Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
---
 drivers/gpio/gpio-xilinx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
index b6d3a57e27ed..7f8e2fed2988 100644
--- a/drivers/gpio/gpio-xilinx.c
+++ b/drivers/gpio/gpio-xilinx.c
@@ -99,7 +99,7 @@ static inline void xgpio_set_value32(unsigned long *map, int bit, u32 v)
 	const unsigned long offset = (bit % BITS_PER_LONG) & BIT(5);
 
 	map[index] &= ~(0xFFFFFFFFul << offset);
-	map[index] |= v << offset;
+	map[index] |= (unsigned long)v << offset;
 }
 
 static inline int xgpio_regoffset(struct xgpio_instance *chip, int ch)
-- 
2.17.1

Re: [PATCH] gpio: gpio-xilinx: Fix integer overflow

Posted by Bartosz Golaszewski 3 years, 8 months ago

On Thu, Jul 21, 2022 at 9:39 AM Srinivas Neeli
<srinivas.neeli@xilinx.com> wrote:
>
> Current implementation is not able to configure more than 32 pins
> due to incorrect data type. So type casting with unsigned long
> to avoid it.
>
> Fixes: 02b3f84d9080 ("xilinx: Switch to use bitmap APIs")
> Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
> ---
>  drivers/gpio/gpio-xilinx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> index b6d3a57e27ed..7f8e2fed2988 100644
> --- a/drivers/gpio/gpio-xilinx.c
> +++ b/drivers/gpio/gpio-xilinx.c
> @@ -99,7 +99,7 @@ static inline void xgpio_set_value32(unsigned long *map, int bit, u32 v)
>         const unsigned long offset = (bit % BITS_PER_LONG) & BIT(5);
>
>         map[index] &= ~(0xFFFFFFFFul << offset);
> -       map[index] |= v << offset;
> +       map[index] |= (unsigned long)v << offset;
>  }
>
>  static inline int xgpio_regoffset(struct xgpio_instance *chip, int ch)
> --
> 2.17.1
>

Applied, thanks!

Bart

Re: [PATCH] gpio: gpio-xilinx: Fix integer overflow

Posted by Andy Shevchenko 3 years, 8 months ago

On Fri, Jul 22, 2022 at 9:19 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> On Thu, Jul 21, 2022 at 9:39 AM Srinivas Neeli
> <srinivas.neeli@xilinx.com> wrote:
> >
> > Current implementation is not able to configure more than 32 pins
> > due to incorrect data type. So type casting with unsigned long
> > to avoid it.

> > Fixes: 02b3f84d9080 ("xilinx: Switch to use bitmap APIs")

It doesn't fix anything,  I already reject one such "fix" during
development of this patch. Thanks!

...

> > @@ -99,7 +99,7 @@ static inline void xgpio_set_value32(unsigned long *map, int bit, u32 v)
> >         const unsigned long offset = (bit % BITS_PER_LONG) & BIT(5);
> >
> >         map[index] &= ~(0xFFFFFFFFul << offset);
> > -       map[index] |= v << offset;
> > +       map[index] |= (unsigned long)v << offset;
> >  }

> Applied, thanks!

False positive.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] gpio: gpio-xilinx: Fix integer overflow

Posted by Andy Shevchenko 3 years, 8 months ago

On Mon, Jul 25, 2022 at 10:04 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Fri, Jul 22, 2022 at 9:19 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> > On Thu, Jul 21, 2022 at 9:39 AM Srinivas Neeli
> > <srinivas.neeli@xilinx.com> wrote:
> > >
> > > Current implementation is not able to configure more than 32 pins
> > > due to incorrect data type. So type casting with unsigned long
> > > to avoid it.
>
> > > Fixes: 02b3f84d9080 ("xilinx: Switch to use bitmap APIs")
>
> It doesn't fix anything,  I already reject one such "fix" during
> development of this patch. Thanks!

Sorry, not my day, it was something else that time... See below.

> ...
>
> > > @@ -99,7 +99,7 @@ c
>
> > Applied, thanks!
>
> False positive.

Reading again... You mean that

  unsigned long x = y << 32;

wouldn't work?



-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] gpio: gpio-xilinx: Fix integer overflow

Posted by Andy Shevchenko 3 years, 8 months ago

On Mon, Jul 25, 2022 at 10:21 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Mon, Jul 25, 2022 at 10:04 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Fri, Jul 22, 2022 at 9:19 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> > > On Thu, Jul 21, 2022 at 9:39 AM Srinivas Neeli
> > > <srinivas.neeli@xilinx.com> wrote:

...

> Reading again... You mean that
>
>   unsigned long x = y << 32;
>
> wouldn't work?

Yeah, I even checked this in asm, and indeed it doesn't work. Don't
know what was that about me...


Thanks for the fix,
Reviewed-by: Andy Shevchenko <andy.shevchenlko@gmail.com>


-- 
With Best Regards,
Andy Shevchenko