[PATCH v2 08/13] media: ar0521: don't overflow when checking PLL values

Mauro Carvalho Chehab posted 13 patches 1 month, 1 week ago
[PATCH v2 08/13] media: ar0521: don't overflow when checking PLL values
Posted by Mauro Carvalho Chehab 1 month, 1 week ago
The PLL checks are comparing 64 bit integers with 32 bit
ones, as reported by Coverity. Depending on the values of
the variables, this may underflow.

Fix it ensuring that both sides of the expression are u64.

Fixes: 852b50aeed15 ("media: On Semi AR0521 sensor driver")
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/i2c/ar0521.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/i2c/ar0521.c b/drivers/media/i2c/ar0521.c
index fc27238dd4d3..24873149096c 100644
--- a/drivers/media/i2c/ar0521.c
+++ b/drivers/media/i2c/ar0521.c
@@ -255,10 +255,10 @@ static u32 calc_pll(struct ar0521_dev *sensor, u32 freq, u16 *pre_ptr, u16 *mult
 			continue; /* Minimum value */
 		if (new_mult > 254)
 			break; /* Maximum, larger pre won't work either */
-		if (sensor->extclk_freq * (u64)new_mult < AR0521_PLL_MIN *
+		if (sensor->extclk_freq * (u64)new_mult < (u64)AR0521_PLL_MIN *
 		    new_pre)
 			continue;
-		if (sensor->extclk_freq * (u64)new_mult > AR0521_PLL_MAX *
+		if (sensor->extclk_freq * (u64)new_mult > (u64)AR0521_PLL_MAX *
 		    new_pre)
 			break; /* Larger pre won't work either */
 		new_pll = div64_round_up(sensor->extclk_freq * (u64)new_mult,
-- 
2.47.0
Re: [PATCH v2 08/13] media: ar0521: don't overflow when checking PLL values
Posted by Krzysztof Hałasa 1 month, 1 week ago
Hi Mauro,

Mauro Carvalho Chehab <mchehab+huawei@kernel.org> writes:

> The PLL checks are comparing 64 bit integers with 32 bit
> ones, as reported by Coverity. Depending on the values of
> the variables, this may underflow.
>
> Fix it ensuring that both sides of the expression are u64.
>
> Fixes: 852b50aeed15 ("media: On Semi AR0521 sensor driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Acked-by: Krzysztof Hałasa <khalasa@piap.pl>

> --- a/drivers/media/i2c/ar0521.c
> +++ b/drivers/media/i2c/ar0521.c
> @@ -255,10 +255,10 @@ static u32 calc_pll(struct ar0521_dev *sensor, u32 freq, u16 *pre_ptr, u16 *mult
>                         continue; /* Minimum value */
>                 if (new_mult > 254)
>                         break; /* Maximum, larger pre won't work either */
> -               if (sensor->extclk_freq * (u64)new_mult < AR0521_PLL_MIN *
> +               if (sensor->extclk_freq * (u64)new_mult < (u64)AR0521_PLL_MIN *
>                     new_pre)
>                         continue;
> -               if (sensor->extclk_freq * (u64)new_mult > AR0521_PLL_MAX *
> +               if (sensor->extclk_freq * (u64)new_mult > (u64)AR0521_PLL_MAX *
>                     new_pre)
>                         break; /* Larger pre won't work either */
>                 new_pll = div64_round_up(sensor->extclk_freq * (u64)new_mult,
-- 
Krzysztof "Chris" Hałasa

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