[PATCH 4/7] media: ov9650: add a sanity check

From: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
To: Linux Media Mailing List <linux-media@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Mauro Carvalho Chehab <mchehab@infradead.org>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Akinobu Mita <akinobu.mita@gmail.com>,
	Sylwester Nawrocki <s.nawrocki@samsung.com>
Subject: [PATCH 4/7] media: ov9650: add a sanity check
Date: Thu, 22 Aug 2019 16:39:31 -0300	[thread overview]
Message-ID: <2868a99c83f1cfef93058f7e49aefa4b104b644f.1566502743.git.mchehab+samsung@kernel.org> (raw)
In-Reply-To: <4a411ba155eb062b6575aba0824123c840806c0b.1566502743.git.mchehab+samsung@kernel.org>

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

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@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 8b56011446a9..cb49fda902fd 100644
--- a/drivers/media/i2c/ov9650.c
+++ b/drivers/media/i2c/ov9650.c
@@ -703,6 +703,11 @@ 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 val */
+		if (m < 0)
+			return -EINVAL;
+
 		rgain = (gain - ((1 << m) * 16)) / (1 << m);
 		rgain |= (((1 << m) - 1) << 4);
 
-- 
2.21.0

