[PATCH] iio: accel: mma9551_core: Prevent uninitialized variable in mma9551_read_status_word()

From: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
To: unlisted-recipients:; (no To-header on input)
Cc: harshit.m.mogalapalli@oracle.com, error27@gmail.com,
	Jonathan Cameron <jic23@kernel.org>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Irina Tirdea <irina.tirdea@intel.com>,
	Vlad Dogaru <ddvlad@gmail.com>,
	linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] iio: accel: mma9551_core: Prevent uninitialized variable in mma9551_read_status_word()
Date: Thu, 26 Jan 2023 07:21:46 -0800	[thread overview]
Message-ID: <20230126152147.3585874-1-harshit.m.mogalapalli@oracle.com> (raw)

Smatch Warns: drivers/iio/accel/mma9551_core.c:357
	mma9551_read_status_word() error: uninitialized symbol 'v'.

When (offset >= 1 << 12) is true mma9551_transfer() will return -EINVAL
without 'v' being initialized, so check for the error and return.

Fixes: d5b97f5c7dfc ("iio: accel: mma9551: split driver to expose mma955x api")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
---
This is detected using static analysis with smatch, and could probably
be detected by syzkaller fuzzing in future.
---
 drivers/iio/accel/mma9551_core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/accel/mma9551_core.c b/drivers/iio/accel/mma9551_core.c
index 75eee7f7303a..b898f865fb87 100644
--- a/drivers/iio/accel/mma9551_core.c
+++ b/drivers/iio/accel/mma9551_core.c
@@ -357,9 +357,12 @@ int mma9551_read_status_word(struct i2c_client *client, u8 app_id,
 
 	ret = mma9551_transfer(client, app_id, MMA9551_CMD_READ_STATUS,
 			       reg, NULL, 0, (u8 *)&v, 2);
+	if (ret < 0)
+		return ret;
+
 	*val = be16_to_cpu(v);
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_NS(mma9551_read_status_word, IIO_MMA9551);
 
-- 
2.38.1

