| From 4b086524ae95e61b4d4fa91cf1f5d86897cf1abd Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 22 Aug 2019 11:55:07 -0300 |
| Subject: media: ov9650: add a sanity check |
| |
| From: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> |
| |
| [ Upstream commit 093347abc7a4e0490e3c962ecbde2dc272a8f708 ] |
| |
| As pointed by cppcheck: |
| |
| [drivers/media/i2c/ov9650.c:706]: (error) Shifting by a negative value is undefined behaviour |
| [drivers/media/i2c/ov9650.c:707]: (error) Shifting by a negative value is undefined behaviour |
| [drivers/media/i2c/ov9650.c:721]: (error) Shifting by a negative value is undefined behaviour |
| |
| Prevent mangling with gains with invalid values. |
| |
| As pointed by Sylvester, this should never happen in practice, |
| as min value of V4L2_CID_GAIN control is 16 (gain is always >= 16 |
| and m is always >= 0), but it is too hard for a static analyzer |
| to get this, as the logic with validates control min/max is |
| elsewhere inside V4L2 core. |
| |
| Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com> |
| Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/media/i2c/ov9650.c | 5 +++++ |
| 1 file changed, 5 insertions(+) |
| |
| diff --git a/drivers/media/i2c/ov9650.c b/drivers/media/i2c/ov9650.c |
| index 502c72238a4a5..db962e2108adf 100644 |
| --- a/drivers/media/i2c/ov9650.c |
| +++ b/drivers/media/i2c/ov9650.c |
| @@ -708,6 +708,11 @@ static int ov965x_set_gain(struct ov965x *ov965x, int auto_gain) |
| for (m = 6; m >= 0; m--) |
| if (gain >= (1 << m) * 16) |
| break; |
| + |
| + /* Sanity check: don't adjust the gain with a negative value */ |
| + if (m < 0) |
| + return -EINVAL; |
| + |
| rgain = (gain - ((1 << m) * 16)) / (1 << m); |
| rgain |= (((1 << m) - 1) << 4); |
| |
| -- |
| 2.20.1 |
| |