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 1ee6a5527c384..d11de02ecb63e 100644 --- a/drivers/media/i2c/ov9650.c +++ b/drivers/media/i2c/ov9650.c @@ -707,6 +707,11 @@ 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);